JP5756416B2 - Liquefied carbon dioxide supply apparatus, polyurethane foam manufacturing apparatus including the liquefied carbon dioxide supply apparatus, and liquefied carbon dioxide supply method - Google Patents

Description

  The present invention relates to a liquefied carbon dioxide supply device, more specifically, a liquefied carbon dioxide supply device that has a first pump device and supplies liquefied carbon dioxide pressurized by the first pump device, and the liquefied carbon dioxide supply device. The present invention relates to a polyurethane foam manufacturing apparatus and a liquefied carbon dioxide supply method for supplying liquefied carbon dioxide using the liquefied carbon dioxide supply apparatus.

  Polyurethane foam is widely used for heat insulating boards, heat insulating materials by spraying, filling agents and the like. The polyurethane foam usually uses a urethane foam raw material containing a polyisocyanate component, a polyol component, and a foaming agent, and each component is metered and mixed and stirred. Then, the urethane foam raw material mixed and stirred is discharged by a discharge device such as a spray gun, and the urethane foam raw material thus discharged is reacted and solidified while being foamed to produce urethane foam.

  Conventionally, chlorofluorocarbon or the like has been used as a foaming agent for this urethane foam material. However, in recent years, chlorofluorocarbons and the like have been regulated due to problems such as ozone layer destruction, and it has been studied to employ carbon dioxide as a foaming agent for urethane foam materials. When carbon dioxide is used as a foaming agent, it is necessary to use liquefied carbon dioxide and supply a predetermined amount of liquefied carbon dioxide. However, since the critical point of carbon dioxide is about 31 ° C. and about 7 MPa, there is a problem that it tends to become a gas at room temperature and it is difficult to supply a predetermined amount of liquefied carbon dioxide. In particular, when liquefied carbon dioxide is pumped with a metering pump or the like, the pressure of the liquefied carbon dioxide is reduced by suction of the pump, so that the liquefied carbon dioxide is easily vaporized and it is difficult to supply a predetermined amount of liquefied carbon dioxide. is there.

  In order to solve the above problems, development of a liquefied carbon dioxide supply device is underway, and the following patent document describes a technique for supplying a predetermined amount of liquefied carbon dioxide without vaporizing. Specifically, in the liquefied carbon dioxide supply device described in Patent Document 1 below, a pressurized gas container is provided, and the liquefied carbon dioxide is pressurized with an inert gas in the pressurized gas container. A predetermined amount of liquefied carbon dioxide is supplied by measuring the liquefied carbon dioxide pressurized in the pressurized gas container with a metering pump or the like and pumping it. Moreover, in the liquefied carbon dioxide supply device described in Patent Documents 2 and 3 below, a cooling device is provided, and the liquefied carbon dioxide is maintained at a low temperature by the cooling device to suppress vaporization of the liquefied carbon dioxide.

JP 2006-192720 A JP 2003-82050 A JP 2006-29895 A

  According to the liquefied carbon dioxide supply device described in the above-mentioned patent document, it is possible to supply a predetermined amount of liquefied carbon dioxide without vaporizing. However, in the liquefied carbon dioxide supply device described in Patent Document 1, it is necessary to provide a pressurized gas container, which may increase the size of the liquefied carbon dioxide supply device and increase the price. In addition to pressurized gas containers, various devices for pressurizing liquefied carbon dioxide in pressurized gas containers, such as containers containing inert gas, regulators for each container, and open / close valves corresponding to each container Etc., and there is a risk of further increasing the size and cost of the liquefied carbon dioxide supply device. Furthermore, filling the liquefied carbon dioxide into the pressurized gas container, pressurizing the liquefied carbon dioxide filled in the pressurized gas container with an inert gas, etc. is inconvenient because it takes a relatively long time.

  Moreover, in the liquefied carbon dioxide supply device described in Patent Documents 2 and 3, vaporization of the liquefied carbon dioxide is prevented by maintaining the liquefied carbon dioxide at a low temperature by the cooling device. In order to suppress the vaporization of liquefied carbon dioxide, a relatively large cooling device is required. For this reason, even in the liquefied carbon dioxide supply device described in Patent Documents 2 and 3, the size of the liquefied carbon dioxide supply device may increase in size and the price may increase. In addition, as described above, the pressure of the liquefied carbon dioxide is reduced by the suction of the metering pump or the like and the liquefied carbon dioxide is easily vaporized. Therefore, the pressure chamber into which the liquefied carbon dioxide is sucked needs to be cooled.

  In view of the above, it is conceivable to employ a pump having a high compression rate as a metering pump and to pressurize liquefied carbon dioxide by the pump to prevent vaporization of liquefied carbon dioxide. However, simply pressurizing the liquefied carbon dioxide with a pump may cause various problems depending on the pressure in the piping to which the liquefied carbon dioxide is supplied. Specifically, the liquefied carbon dioxide supplied by the liquefied carbon dioxide supply device is usually often mixed with some liquid, and the liquefied carbon dioxide is supplied to a mixing pipe through which the liquid flows. When the supply to the pipe for mixing the liquid decreases for some reason, the liquid pressure in the pipe for mixing may be greatly reduced. In such a case, when high-pressure liquefied carbon dioxide is supplied, The ratio of liquefied carbon dioxide in the mixing pipe is increased, and in an extreme case, only the liquefied carbon dioxide is filled in the pipe, which is not preferable.

  As described above, in order to supply liquefied carbon dioxide appropriately with the liquefied carbon dioxide supply device, there is much room for improvement, and by making various improvements, liquefied carbon dioxide is suitably supplied. It will be possible to do this. The present invention has been made in view of such a situation, and a liquefied carbon dioxide supply device capable of suitably supplying liquefied carbon dioxide, a polyurethane foam production apparatus including the liquefied carbon dioxide supply device, and a liquefaction thereof. It is an object of the present invention to provide a liquefied carbon dioxide supply method using a carbon dioxide supply device.

  In order to solve the above-described problems, a liquefied carbon dioxide supply device of the present invention is a first pump device that pressurizes liquefied carbon dioxide, and for supplying liquefied carbon dioxide pressurized by the first pump device to the outside. A supply passage, an on-off valve for opening and closing the supply passage, and a control device for controlling the operation of the first pump device and the on-off valve, and the liquid fed by the piston pump type second pump device flows in A liquefied carbon dioxide supply device connected to the mixing passage through the on-off valve, wherein the liquefied carbon dioxide supply device is configured such that a liquid pressure in the supply passage and a liquid pressure in the mixing passage are A differential pressure detecting means for detecting a differential pressure, wherein the control device stores the differential pressure detected by the differential pressure detecting means for each detection; and a moving direction of the piston of the second pump device Cut A moving direction switching detection unit that detects the obtained timing for each switching, and when the timing is detected by the moving direction switching detection unit, the timing and the timing detected immediately before the timing, Based on the differential pressure acquired by the differential pressure acquisition unit and the differential pressure acquired by the differential pressure acquisition unit, the hydraulic pressure in the mixing passage is supplied by the differential pressure storage unit. An on-off valve control unit for controlling the operation of the on-off valve so that the valve is opened when the differential pressure is acquired by the differential pressure acquisition unit when it is determined that the pressure is higher than the hydraulic pressure in the passage. Configured to have.

  In order to solve the above problems, the polyurethane foam production apparatus of the present invention includes a liquefied carbon dioxide supply device, a mixing passage to which the liquefied carbon dioxide supply device is connected, and a liquid mainly composed of polyol. A piston container for feeding a liquid supplied from one of the first container and the second container into the mixing passage. A liquefied carbon dioxide as a blowing agent supplied from the liquefied carbon dioxide supply device and the liquid fed by the second pump device are mixed in the mixing passage, Further, the liquid supplied from the other of the first container and the second container is mixed to produce a polyurethane foam.

  Moreover, in order to solve the said subject, the liquefied carbon dioxide supply method of this invention supplies the 1st pump apparatus which pressurizes liquefied carbon dioxide, and the liquefied carbon dioxide pressurized by the 1st pump apparatus outside. The liquefied carbon dioxide supply device having a supply passage for opening and an on-off valve for opening and closing the supply passage is used to open and close the mixing passage into which the liquid fed by the piston pump type second pump device flows. A liquefied carbon dioxide supply method for supplying liquefied carbon dioxide through a valve, wherein the liquefied carbon dioxide supply method detects a differential pressure between a fluid pressure in the supply passage and a fluid pressure in the mixing passage. The differential pressure detecting step, the differential pressure storing step for storing the differential pressure detected in the differential pressure detecting step for each detection, and the timing at which the moving direction of the piston of the second pump device is switched are switched. When the timing is detected in the movement direction switching detection step to be detected at the time and the movement direction switching detection step, the differential pressure between the timing and the timing detected one time before the timing is detected. Based on the differential pressure acquisition step for acquiring the differential pressure stored in the storage step and the differential pressure acquired in the differential pressure acquisition step, the hydraulic pressure in the mixing passage is equal to or higher than the hydraulic pressure in the supply passage. And a valve opening step of opening the on-off valve when a differential pressure is acquired by the differential pressure acquisition unit.

  A liquid is fed into the mixing passage to which the liquefied carbon dioxide supply device of the present invention is connected by a piston pump type second pump device, and the liquid and liquefied carbon dioxide are mixed. As will be described later in detail, this piston pump type second pump device can always feed liquid into the mixing passage. However, when the moving direction of the piston is reversed, the liquid is stopped being sent to the mixing passage for a moment, and the hydraulic pressure in the mixing passage is slightly reduced. In this way, if liquefied carbon dioxide is supplied into the mixing passage from the liquefied carbon dioxide supply device at the timing when the liquid pressure in the mixing passage is slightly lowered, the liquefied carbon dioxide is easily supplied. On the other hand, when the hydraulic pressure in the mixing passage decreases due to a factor different from the reversal of the moving direction of the piston, specifically, for example, in the mixing passage due to lack of liquid fed into the mixing passage. When the hydraulic pressure decreases, the hydraulic pressure in the mixing passage tends to decrease greatly. When liquefied carbon dioxide is supplied into the mixing passage where the hydraulic pressure has dropped significantly, the ratio of liquefied carbon dioxide in the mixing passage increases, and in an extreme case, only the liquefied carbon dioxide is filled in the mixing passage. It is not preferable.

  In view of the above, in the liquefied carbon dioxide supply device of the present invention, the liquid pressure in the mixing passage immediately before the moving direction of the piston is reversed is the liquid pressure of liquefied carbon dioxide, that is, in the supply passage. It is determined whether or not the pressure is higher than the liquid pressure. When the liquid pressure in the mixing passage is higher than or equal to the liquid pressure in the supply passage, liquefied carbon dioxide is supplied. This is because, when the hydraulic pressure in the mixing passage is less than the hydraulic pressure in the supply passage immediately before reversing the piston moving direction, the mixing passage in the mixing passage is caused by a factor different from the reversing of the piston moving direction. This is because the hydraulic pressure is considered to have decreased. Thereby, in the liquefied carbon dioxide supply device of the present invention, it is assumed that the liquefied carbon dioxide is supplied at the timing when the liquid pressure in the mixing passage is slightly lowered, and the liquid pressure in the mixing passage is greatly reduced. In this case, the supply of liquefied carbon dioxide can be prohibited. That is, according to the liquefied carbon dioxide supply apparatus of the invention, the polyurethane foam manufacturing apparatus provided with the liquefied carbon dioxide supply apparatus, and the liquefied carbon dioxide supply method using the liquefied carbon dioxide supply apparatus, liquefied carbon dioxide is suitably supplied. It becomes possible to do.

It is the schematic which shows the polyurethane foam manufacturing apparatus of an Example. It is sectional drawing which shows the metering pump corresponding to the polyol component with which the polyurethane foam manufacturing apparatus of FIG. 1 is provided. It is a block diagram which shows the control apparatus of the liquefied carbon dioxide supply apparatus with which the polyurethane foam manufacturing apparatus of FIG. 1 is equipped. It is a graph with respect to the passage of time of the hydraulic pressure in piping, the detection of the piston position of the metering pump, the opening / closing state of the introduction valve, and the operating state of the metering pump. It is a flowchart which shows a differential pressure detection program. It is a flowchart which shows a liquefied carbon dioxide supply program.

  The “liquefied carbon dioxide supply device” described in the present invention is connected to the mixing passage into which the liquid fed by the piston pump type “second pump device” flows, and mixes the liquefied carbon dioxide with the liquid. It is considered as a device that can. The “second pump device” may be a piston pump type pump device, that is, a pump device having a structure for sending out liquid by reciprocating movement of the piston in the cylinder, and adopts a piston pump type pump device having various structures. Is possible.

  As the “second pump device”, for example, there are two pressure chambers, a liquid is sucked into the first pressure chamber from the outside of the pump device, and a liquid is sent from the second pressure chamber to the mixing passage. A pump device can be employed. More specifically, the diameter of the first piston provided in the first pressure chamber is larger than the diameter of the second piston provided in the second pressure chamber, and the first piston, the second piston, However, in conjunction with each other, they reciprocate in the respective pressure chambers. As a result, when the second piston enters the second pressure chamber, the liquid corresponding to the amount of movement of the second piston is sent out from the second pressure chamber to the mixing passage, Liquid corresponding to the amount of movement of the first piston is sucked into the pressure chamber from the outside of the pump device. On the other hand, when the first piston enters the first pressure chamber, liquid corresponding to the amount of movement of the first piston is sent out from the first pressure chamber to the second pressure chamber, An amount of liquid obtained by subtracting the amount of liquid corresponding to the amount of movement of the first piston from the amount of liquid sent out from the pressure chamber to the second pressure chamber is sent out from the second pressure chamber to the mixing passage. . That is, in the pump device having the above structure, it is possible to always feed the liquid into the mixing passage by one piston pump.

  Moreover, it is possible to employ | adopt the pump apparatus comprised by a pair of piston pumps as a "2nd pump apparatus." Specifically, a pair of piston pumps having one pressure chamber is prepared, and the pair of piston pumps are arranged in parallel. When the piston enters one pressure chamber of the pair of piston pumps, the piston retreats from the other pressure chamber, and when the piston enters the other pressure chamber, the piston moves from one pressure chamber to the piston. The piston of each piston pump is reciprocated so as to retreat. That is, when one pressure chamber of a pair of piston pumps is pressurized, the other pressure chamber is depressurized, and when the other pressure chamber is pressurized, one pressure chamber is depressurized. As described above, by reciprocating the piston, it is possible to always feed the liquid into the mixing passage.

  In the piston pump type pump device having the above structure, the liquid can be constantly fed into the mixing passage by the reciprocating movement of the piston. However, when the moving direction of the piston is reversed, that is, when the piston is located at the dead point, the liquid supply to the mixing passage stops for a moment, and the liquid pressure in the mixing passage slightly decreases. . Thus, if liquefied carbon dioxide is supplied into the mixing passage from the liquefied carbon dioxide supply device at the timing when the liquid pressure in the mixing passage is lowered, it becomes easier to supply liquefied carbon dioxide, and liquefied carbon dioxide Can be stably supplied. On the other hand, the hydraulic pressure in the mixing passage is reduced due to a factor different from the reversal of the moving direction of the piston. When liquefied carbon dioxide is supplied into the mixing passage at the time of the decrease, the ratio of liquefied carbon dioxide in the mixing passage increases, and in an extreme case, only the liquefied carbon dioxide is filled in the mixing passage. Absent.

  Therefore, in the “liquefied carbon dioxide supply device” of the present invention, the liquid pressure of the liquid just before the moving direction of the piston is reversed, that is, the liquid pressure in the mixing passage is the liquid pressure of liquefied carbon dioxide, that is, It is determined whether or not the liquid pressure in the supply passage is equal to or higher than the liquid pressure. When the liquid pressure in the mixing passage is equal to or higher than the liquid pressure in the supply passage, liquefied carbon dioxide is supplied. This is because, when the hydraulic pressure in the mixing passage is less than the hydraulic pressure in the supply passage immediately before reversing the piston moving direction, the mixing passage in the mixing passage is caused by a factor different from the reversing of the piston moving direction. This is because the hydraulic pressure is considered to have decreased. Therefore, according to the “liquefied carbon dioxide supply device” of the present invention, it becomes possible to supply liquefied carbon dioxide into the mixing passage at a suitable timing.

  The specific method of supplying liquefied carbon dioxide in the “liquefied carbon dioxide supply device” of the present invention first detects and detects the differential pressure between the liquid pressure in the mixing passage and the liquid pressure in the supply passage. The differential pressure is memorized every time. The detection of the differential pressure may be performed at a constant cycle, specifically, a cycle of several milliseconds to several hundred milliseconds, or may be repeatedly performed at irregular intervals. Then, the timing at which the moving direction of the piston of the second pump device is switched is detected, and the differential pressure stored immediately before the timing is detected is acquired. Subsequently, based on the acquired differential pressure, it is determined whether the hydraulic pressure in the mixing passage is equal to or higher than the hydraulic pressure in the supply passage, and the hydraulic pressure in the mixing passage is determined by the liquid pressure in the supply passage. When the pressure is higher than the pressure, the on-off valve provided in the supply passage is opened. As a result, liquefied carbon dioxide is supplied in accordance with the switching of the moving direction of the piston, and the liquefied carbon dioxide is reduced when the hydraulic pressure in the mixing passage is reduced due to a factor different from the switching of the moving direction of the piston. Can be prohibited.

  Moreover, you may start pressurization of the liquefied carbon dioxide by a 1st pump apparatus with valve opening of an on-off valve. Thereby, liquefied carbon dioxide can be suitably fed into the mixing passage. The “first pump device” only needs to have a structure capable of pressurizing liquefied carbon dioxide, and various structures such as a non-volumetric pump and a volumetric pump can be employed. However, in order to measure the liquefied carbon dioxide to be supplied, it is preferable to employ a positive displacement pump as the “first pump device”, and in particular, what pressurizes the liquid by reciprocating movement of the piston in the cylinder, so-called It is preferable to employ a piston pump type pump device. When a piston pump type pump device is adopted as the “first pump device”, a piston pump having two pressure chambers, or one pressure chamber, as in the case of the “second pump device”. It is preferable that the first pump device is configured by a pair of piston pumps having the pump pump so that liquefied carbon dioxide can be supplied at all times.

  When a piston pump type pump device is adopted as the “first pump device”, when the delivery of one liquefied carbon dioxide by the first pump device is completed, that is, the piston of the first pump device is When stopping at the dead point, the open / close valve of the supply passage may be closed. Thereby, supply of liquefied carbon dioxide can be stopped at a suitable timing.

  Also, liquefied carbon dioxide is easy to vaporize because of its low boiling point. And when liquefied carbon dioxide vaporizes, there exists a possibility that a predetermined amount of carbon dioxide cannot be supplied. Therefore, the liquefied carbon dioxide is preferably maintained at a high pressure and a low temperature in the liquefied carbon dioxide supply apparatus. Specifically, it is preferable to employ a piston pump having a high compression rate as the first piston device in order to maintain the liquefied carbon dioxide at a high pressure. Specifically, for example, it is preferable to employ a piston pump in which the inner diameter of the cylinder and the outer diameter of the piston are almost the same, and the liquefied carbon dioxide in the pressure chamber can be efficiently pressurized.

  Furthermore, it is preferable to provide a cooling device for cooling the pressure chamber in the first piston device in order to prevent the liquefied carbon dioxide from being vaporized when the liquefied carbon dioxide is depressurized in the pressure chamber of the first piston. . Also, since the liquefied carbon dioxide before being pressurized by the first piston device in the liquefied carbon dioxide supply device is highly likely to vaporize, a manifold having a cooling device may be provided upstream of the first piston device. preferable. This manifold includes a plurality of pipes branched into the inside, and when the liquefied carbon dioxide passes through the inside of the plurality of pipes, the liquefied carbon dioxide can be cooled therein. . Thereby, vaporization of the liquefied carbon dioxide in the liquefied carbon dioxide supply device 12 can be suppressed. Incidentally, as long as the cooling device of the first piston device and the manifold can cool liquefied carbon dioxide, various devices can be adopted. It is preferable to employ a cooling device using a Peltier element.

  Various liquids can be used as the liquid mixed with the liquefied carbon dioxide supplied by the “liquefied carbon dioxide supply device” of the present invention, that is, the liquid fed into the mixing passage by the second pump device. However, when the liquefied carbon dioxide supply apparatus is used in a polyurethane foam production apparatus, a polyol or polyisocyanate that is a raw material of the polyurethane foam is adopted as the liquid fed into the mixing passage by the second pump apparatus.

  When liquefied carbon dioxide is supplied to the polyol and polyisocyanate, the liquefied carbon dioxide is supplied as a polyurethane foam raw material and functions as a foaming agent. The supply amount of liquefied carbon dioxide supplied as the urethane foam raw material is preferably 0.1 to 4.0% by mass when the total amount of the polyurethane foam raw material is 100% by mass. Furthermore, it is preferably 0.2 to 2.3% by mass, and particularly preferably 0.6 to 0.8% by mass.

  When liquefied carbon dioxide is supplied as a polyurethane foam raw material, the liquefied carbon dioxide may be blended in at least one of a polyol and a polyisocyanate, and may be blended in two components. Moreover, as a polyurethane foam raw material to which liquefied carbon dioxide is supplied, in addition to polyol and polyisocyanate, a foaming agent other than liquefied carbon dioxide, a catalyst, a crosslinking agent, a foam stabilizer, and the like may be blended. The catalyst, the crosslinking agent, the foam stabilizer and the like may be blended in the polyol before the liquefied carbon dioxide is blended or the polyisocyanate before the liquefied carbon dioxide is blended. In other words, the “liquid based on polyisocyanate” or the “liquid based on polyol” described in the present invention means that polyisocyanate or polyol contains a foaming agent, a catalyst, a crosslinking agent, a foam stabilizer, and the like. The contained liquid may be sufficient.

  In addition, the “polyol” of the present invention is not particularly limited as long as it is normally employed as a urethane foam raw material, and examples thereof include polyester polyols and polyether polyols. Some polyester polyols are obtained by a condensation reaction between a polyhydric alcohol and a polycarboxylic acid. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butanediol, butylene glycol, glycerin, trimethylolpropane, and the like, and these can be used alone or in combination of two or more. Examples of the polyvalent carboxylic acid include glutaric acid, adipic acid, maleic acid, terephthalic acid, and isophthalic acid, and these can be used alone or in combination of two or more. Furthermore, the polyester polyol obtained by ring-opening condensation of caprolactone, methylvalerolactone, etc. is mentioned. Examples of polyether polyols include addition polymerization of oxides such as ethylene oxide, propylene oxide, trimethylene oxide, and butylene oxide to polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, glycerin, trimethylolpropane, and sorbitol. Can be mentioned. It is possible to use one or a combination of two or more of these various polyols as the urethane foam raw material.

  The “polyisocyanate” of the present invention is not particularly limited as long as it is normally employed as a urethane foam raw material, and examples thereof include aromatic isocyanate, aliphatic isocyanate, and alicyclic isocyanate. Examples of the aromatic isocyanate include toluene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), polymeric MDI (crude MDI), xylylene diisocyanate, 1,5-naphthalene diisocyanate, and the like. Examples of the aliphatic isocyanate include hexamethylene diisocyanate, isopropylene diisocyanate, and methylene diisocyanate. Examples of the alicyclic isocyanate include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, and hydrogenated MDI. A combination of one or more of these various polyisocyanates can be used as the urethane foam raw material.

  The following examples illustrate the present invention more specifically. However, the present invention is not limited to this embodiment, and can be implemented in various modes with various modifications and improvements based on the knowledge of those skilled in the art.

<Configuration of polyurethane foam production equipment>
In FIG. 1, the polyurethane foam manufacturing apparatus 10 of the Example of this invention is shown. The polyurethane foam manufacturing apparatus 10 includes a liquefied carbon dioxide supply device 12, and the liquefied carbon dioxide supply device 12 is configured to supply liquefied carbon dioxide intermittently (discontinuously) with a piston pump type metering pump. ing. On the other hand, a liquid mainly composed of polyol (hereinafter sometimes referred to as “polyol component”) is continuously sent out by a piston pump type metering pump. The pump piston corresponding to the liquefied carbon dioxide is reciprocated in accordance with the pump piston corresponding to the polyol component.

  As a result, the liquefied carbon dioxide pump operates intermittently in conjunction with the polyol component pump for the flow path that continuously feeds a certain amount of raw material by the metering pump that pumps the polyol component. (Discontinuous). Therefore, the mixing ratio of the liquefied carbon dioxide to the polyol component is almost constant as a whole, but is mixed inhomogeneously when fed. The heterogeneous liquid mixture is almost homogeneously mixed while being pumped through a static mixer set in the pumping flow path or a pumped flow path (for example, a heater hose having a long extension).

  Then, after the liquid in which the polyol component and liquefied carbon dioxide are mixed is further mixed with a liquid containing polyisocyanate as a main component (hereinafter sometimes referred to as “polyisocyanate component”), the mixed liquid Is discharged from the spray gun 14 to form a polyurethane foam. In the following, the configuration of the polyurethane foam manufacturing apparatus 10 will be specifically described, and the liquefied carbon dioxide is supplied by linking the piston of the pump corresponding to liquefied carbon dioxide and the piston of the pump corresponding to the polyol component. The control of the liquefied carbon dioxide supply device 12 will be described.

  The liquefied carbon dioxide supply device 12 includes a liquefied carbon dioxide cylinder 20 for storing liquefied carbon dioxide, a piston pump type carbon dioxide pump device 22 for pressurizing the liquefied carbon dioxide, a liquefied carbon dioxide cylinder 20 and a carbon dioxide pump device. And a manifold 24 disposed between them.

  The liquefied carbon dioxide cylinder 20 contains liquefied carbon dioxide in a pressurized state (5 to 6 MPa in this embodiment), and a regulator 26 is provided at the supply port 20a of the liquefied carbon dioxide cylinder 20. ing. The regulator 26 is connected to the manifold 24 via a pipe 28, and a filter 30 is provided on the pipe 28.

  The manifold 24 includes a plurality of branched pipes 32 connected to the pipes 28 and a cooling device 36 attached to the back surface of the housing 34. The cooling device 36 includes a Peltier element (not shown) having a cooling surface and a heat dissipation surface, and the cooling surface is in close contact with the back surface of the housing 34. Thereby, the manifold 24 is configured to cool the liquefied carbon dioxide when the liquefied carbon dioxide flows through the plurality of pipes 32. Incidentally, the volume in the plurality of pipes 32 is about 65 of the volume of liquefied carbon dioxide delivered in one pressurizing step by the piston pump type carbon dioxide pump device 22 (maximum of about 1.753 ml in this embodiment). The volume is doubled, and the volume is equal to or greater than the discharge amount per minute. By setting the total volume in the pipe 32 of the manifold 24 to such a volume, the liquefied carbon dioxide passing through the manifold 24 can be sufficiently cooled by the cooling device 36 attached to the manifold 24, so the carbon dioxide pump device The temperature of the liquefied carbon dioxide supplied to 22 can be made below a desired temperature (20 ° C.). The manifold 24 is provided with a pressure relief valve 38.

  Ends on the outlet side of the plurality of pipes 32 of the manifold 24 are connected to the carbon dioxide pump device 22 via the pipes 40. The piping 40 is branched at the end portion on the carbon dioxide pump device 22 side, and a supply valve 44 is provided at an unbranched portion on the manifold 24 side. The carbon dioxide pump device 22 includes a pair of piston pump type metering pumps 46a and 46b, and the pair of metering pumps 46a and 46b are connected to branched pipes 40a and 40b.

  Each of the metering pumps 46 a and 46 b includes a cylinder 50, a piston 52 that reciprocates within the cylinder 50, and a cooling device 54 that is attached to the outer wall surface of the cylinder 50. The inner diameter of the cylinder 50 and the outer diameter of the piston 52 are substantially the same, and the pressure chamber 56 is defined by the cylinder 50 and the piston 52. Pipes 40 a and 40 b are connected to the pressure chamber 56, and liquefied carbon dioxide is sucked into the pressure chamber 56 from the pipes 40 a and 40 b. Similarly to the cooling device 36, the cooling device 54 includes a Peltier element (not shown) having a cooling surface and a heat dissipation surface, and the cooling surface is formed on the outer wall surface of the cylinder 50 that partitions the pressure chamber 56. It is in close contact. As a result, the liquefied carbon dioxide sucked into the pressure chamber 56 can be cooled. Each of the pipes 40 a and 40 b is provided with a check valve 58 that prohibits the backflow of liquefied carbon dioxide from the pressure chamber 56 to the manifold 24.

  Further, the pressure chambers 56 of the respective metering pumps 46 a and 46 b are connected to an introduction valve 62 through a pipe 60. The pipe 60 is branched at the end of each metering pump 46a, 46b, and the branched pipes 60a, 60b are connected to the pressure chambers 56 of the metering pumps 46a, 46b. Each of the pipes 60a and 60b is provided with a check valve 64 that prohibits the backflow of liquefied carbon dioxide into the pressure chamber 56, and a pressure relief is provided at an unbranched portion of the pipe 60 on the introduction valve 62 side. A valve 66, a blow valve 68, and a first hydraulic pressure sensor 70 are provided.

  A pipe 72 is connected to the downstream side of the introduction valve 62, and liquefied carbon dioxide supplied from the pipe 72 is supplied to the outside of the liquefied carbon dioxide supply device 12, that is, into the pipe 74 through which the polyol component flows. It is like that. The pipe 72 is provided with a check valve 76 that prohibits the backflow of liquefied carbon dioxide to the introduction valve 62 side.

  The piping 74 to which liquefied carbon dioxide is supplied by the liquefied carbon dioxide supply device 12 is charged with a polyol at a predetermined pressure (in this embodiment, about 8 Mpa) by a metering pump 80 from a first container 78 containing a polyol component. Ingredients are being sent. Specifically, as shown in FIG. 2, the metering pump 80 has a structure of a piston pump type having two pressure chambers. As the piston rod 86 moves, the first pressure chamber has a first container. The polyol component is sucked from 78, and the polyol component is sent to the pipe 74 from the second pressure chamber.

  Specifically, the metering pump 80 includes a generally cylindrical cylinder 88 and a piston rod 86 that reciprocates within the cylinder 88. The inside of the cylinder 88 communicates with the first chamber 92 located on one end side, the second chamber 94 having a larger diameter than the first chamber 92, and the first chamber 92 on the other end side. A third chamber 96 having substantially the same diameter as 92, a second chamber 94 and a third chamber 96 communicating with each other, and a fourth chamber 98 having a smaller diameter than the third chamber 96 are configured. On the other hand, the piston rod 86 includes a first piston portion 100 located on one end side, a second piston portion 102 located on the other end side, and a connecting portion that connects the first piston portion 100 and the second piston portion 102. 104.

  The first piston portion 100 has an outer diameter substantially the same as the inner diameter of the first chamber 92 and is inserted into the first chamber 92, and the second piston portion 102 has an outer diameter of the fourth chamber. It is substantially the same as the inner diameter of 98 and is inserted into the fourth chamber 98. The connecting portion 104 has an outer diameter substantially the same as the inner diameter of the second chamber 94 and is inserted into the second chamber 94. Thereby, the piston rod 86 can be reciprocated in the cylinder 88. Note that the second piston portion 102 inserted into the fourth chamber 98 extends to the third chamber 96.

  The first chamber 92 is connected to the first container 78 via a pipe 110, and the check valve 112 that prohibits the backflow of liquefied carbon dioxide to the first container 78 is provided in the pipe 110. . The first chamber 92 is further connected to the third chamber 96 via a pipe 114, and the check valve 116 for prohibiting the backflow of liquefied carbon dioxide into the first chamber 92 is provided in the pipe 114. ing. A pipe 74 to which liquefied carbon dioxide is supplied by the liquefied carbon dioxide supply device 12 is connected to the third chamber 96, and the backflow of the liquefied carbon dioxide to the third chamber 96 is prohibited in the pipe 74. A check valve 118 is provided.

  With such a structure, the metering pump 80 can always feed the polyol component from the first container 78 to the pipe 74 by the reciprocating movement of the piston rod 86. Specifically, the fluid flows through a portion of the second chamber 94 on the first chamber 92 side partitioned by the connecting portion 104 via a flow path (not shown), so that the connecting portion 104 is on the fourth chamber 98 side. In other words, the piston rod 86 moves rightward in the drawing. When the piston rod 86 moves rightward in the drawing, the second piston portion 102 enters the third chamber 96, and the polyol component corresponding to the amount of entry of the second piston portion 102 is from the third chamber 96. It is sent out to the pipe 74. At that time, the first piston part 100 is withdrawn from the first chamber 92, and the polyol component corresponding to the withdrawal amount of the first piston part 100 is sucked from the pipe 110.

  On the other hand, the fluid is flowed through the flow path (not shown) to the portion of the second chamber 94 divided by the connecting portion 104 on the fourth chamber 98 side, so that the connecting portion 104 moves to the first chamber 92 side. That is, the piston rod 86 moves in the left direction in the figure. When the piston rod 86 moves to the left in the figure, the first piston portion 100 enters the first chamber 92, and the polyol component corresponding to the amount of the first piston portion 100 entering from the first chamber 92. It is sent out to the third chamber 96. At this time, the second piston portion 102 is withdrawn from the third chamber 96, but the amount of withdrawal of the second piston portion 102 is smaller than the amount of the polyol component sent from the first chamber 92 to the third chamber 96. An amount of the polyol component obtained by subtracting the retraction amount of the second piston portion 102 from the amount of the polyol component sent out from the first chamber 92 to the third chamber 96 is sent out from the third chamber 96 to the pipe 74.

  As described above, the metering pump 80 can always feed the polyol component from the first container 78 to the pipe 74 by the reciprocating movement of the piston rod 86. Note that the cross-sectional area of the first piston portion 100 is approximately twice the cross-sectional area of the second piston portion 102, and the amount of polyol component delivered when the piston rod 86 moves in one direction and the other The amount of the polyol component delivered during movement in the direction is substantially the same. Further, the pipe 74 is provided with a second hydraulic pressure sensor 119, and the hydraulic pressure of the pipe 74, that is, the hydraulic pressure of the polyol component sent out by the metering pump 80 can be acquired.

  The polyol component delivered from the metering pump 80 and the liquefied carbon dioxide supplied by the liquefied carbon dioxide supply device 12 are mixed by a static mixer 120 provided in a pipe 74 as shown in FIG. Then, the mixed liquid is supplied to the spray gun 14 via the primary heater 122 and the heater hose 124. Incidentally, the heater hose 124 is relatively long, specifically, has a length of about 30 m, and the polyol component and the liquefied carbon dioxide mixed by the static mixer 120 are within the long heater hose 124. Mix properly.

  In addition, the polyurethane foam manufacturing apparatus 10 includes a second container 130 that contains a polyisocyanate component, and a metering pump 134 that is connected to the second container 130 via a pipe 132. The metering pump 134 has substantially the same structure as the metering pump 80 corresponding to the polyol component. Like the metering pump 80, the metering pump 134 is piped from the second container 130 by the reciprocating movement of the piston rod (not shown) of the metering pump 134. The polyisocyanate component can be constantly fed into 136. The polyisocyanate component sent out by the metering pump 134 is supplied to the spray gun 14 via the primary heater 138 and the heater hose 140. In the spray gun 14, the polyisocyanate component and the polyol component mixed with liquefied carbon dioxide are mixed, and the spray gun 14 is operated to mix the polyisocyanate component, polyol component, and liquefied carbon dioxide. The discharged liquid is discharged to form a polyurethane foam.

  The liquefied carbon dioxide supply device 12 includes a control device 150 as shown in FIG. The control device 150 includes a controller 152 mainly composed of a computer having a CPU, a ROM, a RAM, etc., a plurality of drive circuits 154 corresponding to the pair of metering pumps 46 a and 46 b and the introduction valve 62 of the carbon dioxide pump device 22. It has. The controller 152 is connected to drive sources (not shown) of the metering pumps 46a and 46b and the introduction valve 62 via the respective drive circuits 154, and can control the operation of the metering pumps 46a and 46b and the introduction valve 62. It is possible.

  The controller 152 is connected to a first hydraulic pressure sensor 70, a second hydraulic pressure sensor 119, a first piston position detection sensor 156, and a second piston position detection sensor 158. The first piston position detection sensor 156 is provided in the metering pumps 46 a and 46 b of the carbon dioxide pump device 22. That is, the piston 52 of the metering pumps 46 a and 46 b is located at the end of the cylinder 50, that is, This is a device for detecting that the piston 52 is located at the dead point. Specifically, this is a device that detects that the piston 52 is positioned at the piston position when the volume of the pressure chamber 56 is the smallest and the piston position when the volume of the pressure chamber 56 is the largest. . On the other hand, the second piston position detection sensor 158 is provided in the metering pump 80 corresponding to the polyol component, and the piston rod 86 of the metering pump 80 is located at the end most in the cylinder 88, that is, the first It is a device that detects that the first piston portion 100 and the second piston portion 102 are located at the dead center. Specifically, when the volume of the first chamber 92 becomes the smallest, that is, when the volume of the third chamber 96 becomes the largest, and when the volume of the first chamber 92 becomes the largest, that is, This is a device for detecting that the piston rod 86 is located at the piston position when the volume of the third chamber 96 is minimized.

<Control of liquefied carbon dioxide supply device>
In the polyurethane foam manufacturing apparatus 10, the polyol component can be constantly fed into the pipe 74 by the reciprocating movement of the piston rod 86 of the metering pump 80. However, when the moving direction of the piston rod 86 is reversed, that is, when the second piston position detection sensor 158 detects that the piston portions 100 and 102 are located at the dead point, the metering pump is instantaneously displayed. liquid pressure of the polyol component is fed from 80 to the pipe 74, i.e., the fluid pressure P ₂ in the pipe 74 detected by the second hydraulic pressure sensor 119 is lowered slightly. This graph over time of the hydraulic P ₂ in the pipe 74 (see FIG. 4 (a)) and a graph over time of the detection result by the second piston position detecting sensor 158 (see FIG. 4 (c)) It is clear by comparing with. Incidentally, the detection result by the second piston position detection sensor 158 is “ON” when the piston portions 100 and 102 are located at the dead point.

Thus, at the timing when the fluid pressure P ₂ in the pipe 74 is reduced, be supplied liquefied carbon dioxide from a liquefied carbon dioxide supply apparatus 12 into the pipe 74, it becomes easy to supply the liquefied carbon dioxide, liquefied dioxide It becomes possible to supply carbon stably. However, if the fluid pressure P ₂ in the pipe 74 by reversing the different factors in the movement direction of the piston rod 86 is lowered, specifically, for example, in the pipe 74 by a shortage of the polyol component in the first container 78 in some cases hydraulic pressure P ₂ decreases. In such a case, as shown in time t ₄ later in FIG. 4 (a), the there is a risk that the fluid pressure P ₂ is greatly reduced in the pipe 74. Thus, when the fluid pressure P ₂ in the pipe 74 is greatly reduced, the liquefied carbon dioxide in the pipe 74 is supplied, the ratio of the liquefied carbon dioxide in the pipe 74 is increased, speaking extremely, The piping 74 is filled only with liquefied carbon dioxide, which is not preferable.

Therefore, in the liquefied carbon dioxide supply device 12, the hydraulic pressure P ₂ in the pipe 74 immediately before the moving direction of the piston rod 86 is reversed is detected by the hydraulic pressure of the liquefied carbon dioxide, that is, the first hydraulic pressure sensor 70. determining whether a hydraulic P ₁ or more in the pipe 60 to be hydraulic P ₂ in the pipe 74, only if it is the hydraulic P ₁ or more in the pipe 60, supplying the liquefied carbon dioxide doing. This FIG 4 (a), (c) and, the pipe 60 in the graph over time of the hydraulic _{P 1} of As is clear from (see FIG. 4 (b)), the moving direction of the reversal of the piston rod 86 relationship between the fluid pressure _{P 1} and the fluid pressure _{P 2} of the previous time, the time _t 1 ~ when the hydraulic pressure _{P 2} in the pipe 74 by the movement direction of the reversing of the piston rod 86 is lowered (see FIG. 4 (a) At t ₃ ), the hydraulic pressure P ₁ and the hydraulic pressure P ₂ are the same, that is, the hydraulic pressure P ₂ is equal to or higher than the hydraulic pressure P _1, and the piping 74 is caused by a shortage of the polyol component in the first container 78. in the case where the hydraulic pressure _{P 2} of the inner is reduced (time _{t 4} after the FIG. 4 (a)), the hydraulic pressure _{P 2} is for less than the fluid pressure _{P 1.}

Incidentally, before the liquefied carbon dioxide is supplied from the pipe 60 to the pipe 74, the liquefied carbon dioxide of the hydraulic, i.e., the fluid pressure P ₁ in the pipe 60 is pressurized to about 8 Mpa. Specifically, in the state where the introduction valve 62 is closed, the pressure chamber 56 is pressurized by one piston 52 of the pair of metering pumps 46a and 46b, and the pressure chamber 56 is filled by the other piston 52. Reduce pressure. When each piston 52 moves to the dead point, the inside of the pressure chamber 56 is pressurized by the other piston 52 while the inside of the pressure chamber 56 is decompressed by the one piston 52. Thus, the hydraulic pressure P ₁ in the pipe 60 is pressurized to 8 Mpa by repeatedly moving the piston 52 in a reciprocating manner.

Then, in the state where the hydraulic pressure P ₁ in the pipe 60 is pressurized to 8 MPa, as described above, it is determined whether or not the hydraulic pressure P ₂ in the pipe 74 is equal to or higher than the hydraulic pressure P ₁ in the pipe 60. When it is determined that it is determined that the hydraulic pressure P ₂ in the pipe 74 is equal to or higher than the hydraulic pressure P ₁ in the pipe 60, it is preferable to supply liquefied carbon dioxide, that is, to open the introduction valve 62. It becomes possible to supply liquefied carbon dioxide to the pipe 74. By determining whether or not to supply the liquefied carbon dioxide in this way, the liquefied carbon dioxide is reduced at the timing (time t _{1 to} t _{3 in} FIG. 4A) when the hydraulic pressure P ₂ in the pipe 74 slightly decreases. is supplied to the pipe 74, in the case where the fluid pressure P ₂ in the pipe 74 is greatly reduced (FIGS. 4 (a) time t ₄ later), it becomes possible to prohibit the supply to the pipe 74 of the liquid carbon dioxide . The supply state of liquefied carbon dioxide is apparent from the graph with respect to the passage of time of the opening / closing state of the introduction valve 62 shown in FIG.

  Further, when the liquefied carbon dioxide is supplied, pressurization of the liquefied carbon dioxide by the carbon dioxide pump device 22 is started as the introduction valve 62 is opened. Specifically, simultaneously with the opening of the introduction valve 62, one piston 52 of the pair of metering pumps 46a and 46b is moved so as to pressurize the inside of the pressure chamber 56, and the other piston 52 is moved to the pressure chamber 56. The inside is moved so as to reduce the pressure. Thereby, it becomes possible to supply liquefied carbon dioxide to the piping 74 more suitably. The operating conditions of the pair of metering pumps 46a and 46b are shown in FIGS. 4 (e) and 4 (f).

  Simultaneously with the opening of the introduction valve 62, the movement of the piston 52 of each metering pump 46a, 46b is started. The stroke time of the piston 52 of each metering pump 46a, 46b is the piston rod 86 of the metering pump 80. Therefore, before the one pressurizing process by the metering pump 80 is completed, the one pressurizing process by the metering pumps 46a and 46b is completed. This is a graph with respect to the time passage of the detection result by the second piston position detection sensor 158 (see FIG. 4C) and a graph with respect to the passage of time of the detection result by the first piston position detection sensor 156 (FIG. 4G). It is clear by comparing with reference.

  Incidentally, when the piston 52 of the metering pumps 46a and 46b is located at the dead point, the detection result by the first piston position detection sensor 156 is “ON”. That is, while the detection result is “OFF”, the pistons 52 of the metering pumps 46a and 46b are moving.

Thus, before one pressurization process by the metering pump 80 is completed, one pressurization process by the metering pumps 46a and 46b is completed, and one pressurization by the metering pumps 46a and 46b is completed. Simultaneously with the end of the process, the supply of liquefied carbon dioxide is stopped, that is, the introduction valve 62 is closed. Thereby, supply of the liquefied carbon dioxide by one pressurization process of metering pumps 46a and 46b is completed. As long as the hydraulic pressure P ₂ in the pipe 74 immediately before the piston rod 86 is reversed does not become less than the hydraulic pressure P ₁ in the pipe 60, the liquefied carbon dioxide produced by the pressurizing process of the metering pumps 46 a and 46 b is one. Supply is repeated.

<Differential pressure detection program and liquefied carbon dioxide supply program>
The control of the liquefied carbon dioxide supply device 12 as described above is performed by the controller 152 of the control device 150 executing the differential pressure detection program shown in the flowchart of FIG. 5 and the liquefied carbon dioxide supply program shown in FIG. Is called. The differential pressure detection program is repeatedly executed at a short time interval (for example, several hundred msec), and the liquefied carbon dioxide supply program is repeatedly executed at a time interval (for example, several msec) shorter than the execution interval of the differential pressure detection program. Executed.

First, in the differential pressure detection program, as shown in FIG. 5, in step 1 (hereinafter simply referred to as “S1”. The same applies to other steps), the first hydraulic pressure sensor 70 causes the liquid in the pipe 60 to flow. pressure _{P 1} is detected. Next, in S2, the fluid pressure _{P 2} in the pipe 74 is detected by the second hydraulic pressure sensor 119. Subsequently, in S3, the differential pressure [Delta] P, that is, the value obtained by subtracting the hydraulic pressure _{P 1} of the pipe 60 from the hydraulic _{P 2} in the pipe 74 is calculated. In S4, the calculated differential pressure ΔP is stored, and one execution of this program is completed. Incidentally, the process of S3 corresponds to a differential pressure detection process, and the process of S4 corresponds to a differential pressure storage process.

  In the liquefied carbon dioxide supply program, as shown in FIG. 6, it is determined in S11 whether or not the operation switch of the liquefied carbon dioxide supply device 12 is ON, and it is determined that the operation switch is ON. If so, it is determined in S12 whether or not the introduction valve 62 has been opened. Incidentally, the initial introduction valve 62 of the operation of the liquefied carbon dioxide supply device 12 is closed. If it is determined that the introduction valve 62 is not opened, the position of the piston rod 86 of the metering pump 80 is detected in S13. Specifically, the position of the piston rod 86 is detected by the second piston position detection sensor 158.

Next, in S14, based on the detection result by the second piston position detection sensor 158, it is determined whether or not the operation direction of the piston rod 86 has been switched. If it is determined that the operation direction of the piston rod 86 has been switched, the differential pressure stored most recently among the differential pressures ΔP stored in the differential pressure detection program, that is, the latest differential pressure ΔP in S15. _N is acquired. In other words, differential pressure switching operation direction is stored immediately before is determined timing is acquired as the latest differential pressure [Delta] P _N.

Subsequently, in S16, whether the latest differential pressure [Delta] P _N is 0 or more is determined. That is, it is determined whether or not the hydraulic pressure P ₂ in the pipe 74 is equal to or higher than the hydraulic pressure P ₁ in the pipe 60. When the fluid pressure P ₂ in the pipe 74 is determined to be the fluid pressure P ₁ or more in the pipe 60, at S17, the introduction valve 62 is opened, in S18, as mentioned above, dioxide Pressurization by the carbon pump device 22 is started.

  If it is determined in S12 that the introduction valve 62 is opened, the position of the piston 52 of the metering pumps 46a and 46b is detected in S19. Specifically, the position of the piston 52 is detected by the first piston position detection sensor 156. Next, in S20, based on the detection result by the first piston position detection sensor 156, it is determined whether the piston 52 of the metering pumps 46a, 46b is located at the dead point, that is, whether it is stopped. If it is determined that the piston 52 is stopped, the introduction valve 62 is closed in S21.

  Incidentally, the process of S14 is the detection process at the time of switching the moving direction, the process of S15 is the differential pressure acquisition process, the process of S17 is the valve opening process, the process of S18 is the first pump operation process, and the process of S20 is the piston stop. In the detection process, the process of S21 corresponds to the valve closing process.

<Functional configuration of controller>
The controller 152 of the control device 150 in which the differential pressure detection program and the liquefied carbon dioxide supply program are executed can be considered to have a functional configuration as shown in FIG. 3 according to the execution process. As can be seen from the figure, the controller 152 functions as a functional unit that executes the process of S4, that is, a functional unit that stores the differential pressure ΔP, and a functional unit that executes the process of S14, that is, the weighing unit. As a functional unit for detecting the timing at which the moving direction of the piston rod 86 of the pump 80 is switched, the pump switching time detecting unit 172 is a function unit for executing the processing of S15, that is, the latest immediately before the moving direction of the piston rod 86 is switched. as a functional unit for acquiring the differential pressure [Delta] P _N, the pressure difference obtaining unit 174, a functional portion to execute the processing in S17, S21, i.e., as a functional unit that controls the operation of the inlet valve 62, the introduction valve control unit 176, As a functional unit that executes the process of S20, that is, as a functional unit that detects the stop of the piston 52 of the metering pumps 46a and 46b, a piston stop detecting unit 178 is provided. A functional portion to execute the processing of 18, i.e., as a functional unit that controls the operation of the carbon dioxide pump device 22, the carbon dioxide pump control unit 180, respectively, have.

  Incidentally, in the above embodiment, the polyurethane foam manufacturing apparatus 10 is an example of the polyurethane foam manufacturing apparatus, and the liquefied carbon dioxide supply device 12, the pipe 74, the first container 78, and the second container 130 that constitute the polyurethane foam manufacturing apparatus 10. The metering pump 80 is an example of a liquefied carbon dioxide supply device, a mixing passage, a first container, a second container, and a second pump device. The carbon dioxide pump device 22, the manifold 24, the pipe 60, the introduction valve 62, and the control device 150 that constitute the liquefied carbon dioxide supply device 12 are examples of a first pump device, a manifold, a supply passage, an on-off valve, and a control device. . Further, the differential pressure storage unit 170, the pump switching time detection unit 172, the differential pressure acquisition unit 174, the introduction valve control unit 176, the piston stop detection unit 178, and the carbon dioxide pump control unit 180 of the control device 150 include a differential pressure storage unit, It is an example of the detection part at the time of moving direction switching, a differential pressure | voltage acquisition part, an on-off valve control part, a piston stop detection part, and a 1st pump control part. The plurality of piping 32 and the cooling device 36 of the manifold 24 are examples of a plurality of piping and piping cooling devices. The metering pumps 46a and 46b, the cooling device 54, and the pressure chamber 56 of the carbon dioxide pump device 22 are It is an example of 1 piston pump, a pressure chamber cooling device, and a 1st pressure chamber. Furthermore, what is constituted by the first hydraulic pressure sensor 70 and the second hydraulic pressure sensor 119 is an example of the differential pressure detecting means.

  Hereinafter, various aspects of the present invention will be listed.

(1) a first pump device that pressurizes liquefied carbon dioxide, a supply passage for supplying liquefied carbon dioxide pressurized by the first pump device to the outside, an on-off valve that opens and closes the supply passage, A control device that controls the operation of the first pump device and the on-off valve, and is connected to the mixing passage through which the liquid fed by the piston pump type second pump device flows in via the on-off valve. A liquefied carbon dioxide supply device,
The liquefied carbon dioxide supply device is
A differential pressure detecting means for detecting a differential pressure between the hydraulic pressure in the supply passage and the hydraulic pressure in the mixing passage;
The control device is
A differential pressure storage unit that stores the differential pressure detected by the differential pressure detection means for each detection;
A moving direction switching detection unit that detects, for each switching, a timing at which the moving direction of the piston of the second pump device is switched;
When the timing is detected by the moving direction switching detection unit, the differential pressure stored by the differential pressure storage unit is acquired between the timing and the timing detected immediately before that timing. A differential pressure acquisition unit,
Based on the differential pressure acquired by the differential pressure acquisition unit, when it is determined that the hydraulic pressure in the mixing passage is equal to or higher than the hydraulic pressure in the supply passage, the differential pressure is acquired by the differential pressure acquisition unit. A liquefied carbon dioxide supply apparatus comprising: an on-off valve control unit that controls the operation of the on-off valve so that the valve is opened when acquired.

(2) The control device
The liquefied carbon dioxide supply according to (1), further including a first pump control unit that controls the operation of the first pump device so that pressurization of the liquefied carbon dioxide is started when the on-off valve is opened. apparatus.

  (3) The liquefied carbon dioxide supply device according to item (2), wherein the first pump device is a piston pump type.

(4) The controller is
A piston stop detection unit for detecting a stop of the piston of the first pump device;
The on-off valve controller is
After the start of pressurization of liquefied carbon dioxide accompanying the opening of the on-off valve, the operation of the on-off valve is controlled so as to be closed when the piston stop detection is detected by the piston stop detection unit ( The liquefied carbon dioxide supply device according to item 3).

(5) The first pump device is
The liquefied carbon dioxide supply device according to any one of items (1) to (4), further including a pressure chamber cooling device that cools a pressure chamber for pressurizing the liquefied carbon dioxide.

(6) The liquefied carbon dioxide supply device is
Any of (1) to (5), comprising a plurality of branched pipes and a pipe cooling device that cools the plurality of pipes, and comprising a manifold provided upstream of the first pump device The liquefied carbon dioxide supply device according to any one of the above.

(7) The first pump device includes a pair of first piston pumps,
Each of the pair of first piston pumps has a first pressure chamber for pressurizing liquefied carbon dioxide,
The first pump controller is
The operation of the pair of first piston pumps is performed such that when one of the first pressure chambers of the pair of first piston pumps is pressurized, the other first pressure chamber is depressurized. The liquefied carbon dioxide supply device according to any one of items (2) to (6) to be controlled.

(8) The liquefied carbon dioxide supply device according to any one of (1) to (7),
The mixing passage to which the liquefied carbon dioxide supply device is connected;
A first container containing a liquid mainly composed of polyol;
A second container containing a liquid mainly composed of polyisocyanate;
A piston pump type second pump device for feeding a liquid supplied from one of the first container and the second container into the mixing passage;
The liquefied carbon dioxide as a blowing agent supplied from the liquefied carbon dioxide supply device and the liquid fed by the second pump device are mixed in the mixing passage, and further, the first container and the second A polyurethane foam production apparatus for producing a polyurethane foam by mixing a liquid supplied from the other side of the container.

(9) A first pump device that pressurizes liquefied carbon dioxide, a supply passage for supplying liquefied carbon dioxide pressurized by the first pump device to the outside, and an on-off valve that opens and closes the supply passage. This is a liquefied carbon dioxide supply method for supplying liquefied carbon dioxide to the mixing passage into which the liquid fed by the piston pump type second pump device flows using the liquefied carbon dioxide supply device. And
The liquefied carbon dioxide supply method is
A differential pressure detecting step of detecting a differential pressure between the hydraulic pressure in the supply passage and the hydraulic pressure in the mixing passage;
A differential pressure storage step of storing the differential pressure detected in the differential pressure detection step for each detection;
A moving direction switching detection step for detecting, every switching, a timing at which the moving direction of the piston of the second pump device is switched;
When the timing is detected in the moving direction switching detection step, the differential pressure stored in the differential pressure storage step is acquired between the timing and the timing detected immediately before the timing. Differential pressure acquisition process
When it is determined that the hydraulic pressure in the mixing passage is equal to or higher than the hydraulic pressure in the supply passage based on the differential pressure acquired in the differential pressure acquisition step, the differential pressure is acquired by the differential pressure acquisition section. A liquefied carbon dioxide supply method comprising: a valve opening step of opening the on-off valve when acquired.

(10) The liquefied carbon dioxide supply method is
The liquefied carbon dioxide supply method according to item (9), including a first pump operation step of operating the first pump device so that pressurization of liquefied carbon dioxide is started as the on-off valve is opened.

(11) The first pump device includes a pair of first piston pumps,
Each of the pair of first piston pumps has a first pressure chamber for pressurizing liquefied carbon dioxide,
The first pump operation step includes:
The operation of the pair of first piston pumps is performed such that when one of the first pressure chambers of the pair of first piston pumps is pressurized, the other first pressure chamber is depressurized. The liquefied carbon dioxide supply method according to item (10), which is a controlling step.

(12) The first pump device is a piston pump type,
The liquefied carbon dioxide supply method is
A piston stop detection step of detecting a stop of the piston of the first pump device;
A valve closing step for closing the on-off valve when the piston stop is detected in the piston stop detection step after the start of pressurization of the liquefied carbon dioxide accompanying the opening of the on-off valve. ) Or liquefied carbon dioxide supply method according to item (11).

(13) The first pump device is
The liquefied carbon dioxide supply method according to any one of (9) to (12), further including a pressure chamber cooling device that cools a pressure chamber for pressurizing the liquefied carbon dioxide.

(14) The liquefied carbon dioxide supply device comprises:
Any of (9) to (13), comprising a plurality of branched pipes and a pipe cooling device for cooling the plurality of pipes, and comprising a manifold provided upstream of the first pump device. The liquefied carbon dioxide supply method according to any one of the above.

10: Polyurethane foam manufacturing device 12: Liquefied carbon dioxide supply device 22: Carbon dioxide pump device (first pump device) 24: Manifold 32: Pipe 36: Cooling device (pipe cooling device) 46: Metering pump (first piston pump) 54: Cooling device (pressure chamber cooling device) 56: Pressure chamber (first pressure chamber) 60: Pipe (supply passage) 62: Introduction valve (open / close valve) 70: First hydraulic pressure sensor (differential pressure detection means) 74: Piping (mixing passage) 78: First container 119: Second hydraulic pressure sensor (differential pressure detection means) 130: Second container 150: Control device 170: Differential pressure storage unit 172: Pump switching detection unit (moving direction switching) 174: Differential valve acquisition unit 176: Introduction valve control unit (open / close valve control unit) 178: Piston stop detection unit 180: Carbon dioxide pump control unit (first pump control unit)

Claims (10)

A first pump device that pressurizes liquefied carbon dioxide, a supply passage for supplying liquefied carbon dioxide pressurized by the first pump device to the outside, an on-off valve that opens and closes the supply passage, and the first pump And a control device for controlling the operation of the on-off valve, and liquefied carbon dioxide connected to the mixing passage through which the liquid fed by the piston pump type second pump device flows flows through the on-off valve A feeding device,
The liquefied carbon dioxide supply device is
A differential pressure detecting means for detecting a differential pressure between the hydraulic pressure in the supply passage and the hydraulic pressure in the mixing passage;
The control device is
A differential pressure storage unit that stores the differential pressure detected by the differential pressure detection means for each detection;
A moving direction switching detection unit that detects, for each switching, a timing at which the moving direction of the piston of the second pump device is switched;
When the timing is detected by the moving direction switching detection unit, the differential pressure stored by the differential pressure storage unit is acquired between the timing and the timing detected immediately before that timing. A differential pressure acquisition unit,
Based on the differential pressure acquired by the differential pressure acquisition unit, when it is determined that the hydraulic pressure in the mixing passage is equal to or higher than the hydraulic pressure in the supply passage, the differential pressure is acquired by the differential pressure acquisition unit. A liquefied carbon dioxide supply apparatus comprising: an on-off valve control unit that controls the operation of the on-off valve so that the valve is opened when acquired. The control device is
2. The liquefied carbon dioxide supply device according to claim 1, further comprising a first pump control unit that controls the operation of the first pump device so that pressurization of the liquefied carbon dioxide is started as the on-off valve is opened. .   The liquefied carbon dioxide supply device according to claim 2, wherein the first pump device is a piston pump type. The control device is
A piston stop detection unit for detecting a stop of the piston of the first pump device;
The on-off valve controller is
The operation of the on-off valve is controlled so as to be closed when the piston stop detection is detected by the piston stop detection unit after the start of pressurization of liquefied carbon dioxide accompanying the opening of the on-off valve. Item 4. The liquefied carbon dioxide supply device according to Item 3. The first pump device is
The liquefied carbon dioxide supply device according to any one of claims 1 to 4, further comprising a pressure chamber cooling device that cools a pressure chamber for pressurizing the liquefied carbon dioxide. The liquefied carbon dioxide supply device is
6. The apparatus according to claim 1, further comprising a manifold provided on the upstream side of the first pump device, the pipe having a plurality of branched pipes and a pipe cooling device for cooling the plurality of pipes. The liquefied carbon dioxide supply device according to 1. A liquefied carbon dioxide supply device according to any one of claims 1 to 6,
The mixing passage to which the liquefied carbon dioxide supply device is connected;
A first container containing a liquid mainly composed of polyol;
A second container containing a liquid mainly composed of polyisocyanate;
A piston pump type second pump device for feeding a liquid supplied from one of the first container and the second container into the mixing passage;
The liquefied carbon dioxide as a blowing agent supplied from the liquefied carbon dioxide supply device and the liquid fed by the second pump device are mixed in the mixing passage, and further, the first container and the second A polyurethane foam production apparatus for producing a polyurethane foam by mixing a liquid supplied from the other side of the container. A liquefied carbon dioxide comprising a first pump device that pressurizes liquefied carbon dioxide, a supply passage for supplying liquefied carbon dioxide pressurized by the first pump device to the outside, and an on-off valve that opens and closes the supply passage. A liquefied carbon dioxide supply method for supplying liquefied carbon dioxide to the mixing passage through which the liquid fed by the piston pump type second pump device flows using the carbon supply device, via the on-off valve,
The liquefied carbon dioxide supply method is
A differential pressure detecting step of detecting a differential pressure between the hydraulic pressure in the supply passage and the hydraulic pressure in the mixing passage;
A differential pressure storage step of storing the differential pressure detected in the differential pressure detection step for each detection;
A moving direction switching detection step for detecting, every switching, a timing at which the moving direction of the piston of the second pump device is switched;
When the timing is detected in the moving direction switching detection step, the differential pressure stored in the differential pressure storage step is acquired between the timing and the timing detected immediately before the timing. Differential pressure acquisition process
When it is determined that the hydraulic pressure in the mixing passage is equal to or higher than the hydraulic pressure in the supply passage based on the differential pressure acquired in the differential pressure acquisition step, the differential pressure is acquired by the differential pressure acquisition section. A liquefied carbon dioxide supply method comprising: a valve opening step of opening the on-off valve when acquired. The liquefied carbon dioxide supply method is
The liquefied carbon dioxide supply method according to claim 8, further comprising a first pump operation step of operating the first pump device so that pressurization of liquefied carbon dioxide is started as the on-off valve is opened. The first pump device is a piston pump type,
The liquefied carbon dioxide supply method is
A piston stop detection step of detecting a stop of the piston of the first pump device;
A valve closing step of closing the on-off valve when the piston stop is detected in the piston stop detection step after the start of pressurization of liquefied carbon dioxide accompanying the opening of the on-off valve. 9. The liquefied carbon dioxide supply method according to 9.

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