JP7627953B2 - Low-temperature compressed air supply system and low-temperature compressed air supply method - Google Patents

Description

The present invention relates to a low-temperature compressed air supply system and a low-temperature compressed air supply method that dehumidifies and cools compressed air supplied from an air compressor to discharge dry low-temperature air.

The applicant has previously proposed a cold air supplying device (see Patent Document 2) having a refrigerator that cools compressed air and a cold air blowing section that blows the compressed air cooled by the refrigerator toward a cooling target, characterized in that the device has a flow rate adjustment means that limits the flow rate of cold air blown out from the cold air blowing section during standby operation to zero or a standby operation flow rate that is less than the flow rate during normal operation. This cold air supplying device (low-temperature compressed air supplying device system) can reduce wasted time in processing operations by shortening the pre-cooling preparation time associated with temporary shutdowns.

The applicant has also previously reported on a compressed air cooling device for producing cooled compressed air for use in cooling workpieces, tools, etc., of a machine tool, the device comprising: a first cooling circuit including a first cooler for cooling compressed air and a first refrigerant circulation circuit for circulating a first refrigerant through the first cooler; a second cooling circuit including a second cooler for cooling compressed air supplied via the first cooler and a second refrigerant circulation circuit for circulating a second refrigerant through the second cooler; and a switching control means for simultaneously or selectively using the first cooling circuit and the second cooling circuit to cool the compressed air, the first refrigerant having a higher boiling point than the second refrigerant, The switching control means is based on a preset temperature of the cooled compressed air after being cooled by the second cooler, an inlet temperature which is the temperature of the compressed air before being cooled by the first cooler, and a preset switching control temperature. When the preset temperature is lower than the switching control temperature, the compressed air is cooled using only the second cooling circuit, when the inlet temperature is lower than the switching control temperature, the compressed air is cooled using both the first and second cooling circuits when the inlet temperature is equal to or higher than the switching control temperature, and when the preset temperature is equal to or higher than the switching control temperature, the compressed air is cooled using only the first cooling circuit. This provides a compressed air cooling device (low-temperature compressed air supply system) that has good cooling efficiency over the entire cooling temperature range and also consumes little power.

Conventionally, low-temperature compressed air supply systems have used an adsorption-type dehumidifier (also called a "heatless dryer") as a component thereof.
In this heatless dryer, two adsorption columns (hereinafter also referred to as "adsorption towers") filled with an adsorbent such as activated alumina, silica gel, synthetic zeolite, or lithium chloride are provided to continuously discharge and supply dry gas (e.g., air). Moist compressed air is introduced into one of the adsorption towers to perform adsorption drying, and the obtained dry air is supplied to a specified supply destination. At the same time, a part of the obtained dry air is introduced into the other adsorption tower, and moisture is desorbed from the adsorbent whose moisture absorption capacity has been reduced by absorbing moisture in the previous drying process, and the moisture is purged from the adsorption tower to regenerate the adsorbent. In this regeneration process, generally, about 10% of the obtained dry air is released into the atmosphere. The drying process of the compressed air in one of the adsorption towers and the regeneration process of the adsorbent in the other adsorption tower are performed simultaneously in parallel. In addition, these drying and regeneration processes are performed alternately between the two adsorption towers. For example, a switching valve connected to both adsorption towers is switched every time a predetermined time has elapsed. This allows the dry air to be continuously supplied to a specified supply destination as product air. This two-column method for adjusting the composition of compressed gas is also called the pressure swing method.

In such a gas component adjusting device that uses an adsorbent, if the device is not properly stopped when the device is stopped, the device may not be able to continue to operate properly when the device is restarted.
In response to this, for example, a continuous supply method for dehumidifying compressed gas includes a drying step in which compressed gas is introduced into one of two adsorption towers filled with an adsorbent, where moisture in the compressed gas is adsorbed and dehumidified to discharge dry gas, and a regeneration step in which a part of the compressed gas dried in the drying step is introduced into the other adsorption tower which adsorbed and dehumidified the moisture in the compressed gas in the previous step, where moisture is desorbed from the adsorbent whose adsorption capacity has decreased and the adsorbent is discharged, thereby regenerating the adsorbent. The drying step and the regeneration step are performed substantially alternately between the two adsorption towers, thereby continuously discharging dry gas. The present applicant has proposed a continuous supply method for dehumidifying compressed gas (see Patent Document 1), which is characterized in that in the regeneration process, exhaust is controlled by operating an exhaust valve provided for each adsorption tower and driven to open and close by dried compressed gas supplied from the adsorption tower, and when the pressure of the compressed gas used to drive the exhaust valves to open and close falls below a preset value, both exhaust valves applied to each adsorption tower are closed so that exhaust in the regeneration process is stopped for both adsorption towers, and then operation of the entire apparatus is stopped.

Patent No. 3217030 (Claim 1) Patent No. 3518860 (Claim 1) Patent No. 4351174 (Claim 1)

The problem to be solved by the low-temperature compressed air supply system and the low-temperature compressed air supply method is that, when the compressed air flow rate exceeds the rated flow rate due to a sudden change in the intake air conditions or load change, the conventional system is controlled to stop operation to protect against a rise in the dew point or an overloaded operation state of the ultra-low temperature cooler, but no more reasonable means for protecting the system while continuing operation, such as preventing damage to the filter element, has been proposed. In other words, once operation is stopped, it takes a long time to return to stable operation, resulting in a significant decrease in production efficiency.
Therefore, an object of the present invention is to provide a low-temperature compressed air supply device system and a low-temperature compressed air supply method that can continue operation and protect the system even if the compressed air flow rate increases above the rated flow rate due to a sudden change in intake conditions or load fluctuation.

In order to achieve the above object, the present invention has the following configuration.
According to one embodiment of the low-temperature compressed air supply system of the present invention, there is provided a low-temperature compressed air supply system that dehumidifies and cools compressed air supplied from an air compressor to discharge dry low-temperature air, the system including a heatless dryer which is an adsorption-type dehumidifier that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified dry compressed air, a drying and cooling system unit including a first cooler that cools the dry compressed air supplied from the heatless dryer, and a second cooler that further cools the cooled dry compressed air supplied from the first cooler, a flow control valve that adjusts the flow rate to the rated flow rate when the flow rate of the compressed air flowing through the drying and cooling system unit exceeds the rated flow rate, and a control device that controls the flow control valve.

In addition, according to one embodiment of the low-temperature compressed air supply system of the present invention, the flow control valve can be characterized as being installed on the side of the discharge portion that discharges the product air from the second cooler.

According to one embodiment of the low-temperature compressed air supply system of the present invention, the low-temperature compressed air supply system dehumidifies and cools compressed air supplied from an air compressor to discharge dry low-temperature air, and includes a heatless dryer, an adsorption-type dehumidifier that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified dry compressed air, a drying and cooling system unit that includes a first cooler that cools the dry compressed air supplied from the heatless dryer, and a second cooler that further cools the cooled dry compressed air supplied from the first cooler, and a control device that controls the second cooler to increase its set temperature when the flow rate of the compressed air flowing through the drying and cooling system unit exceeds the rated flow rate.

According to one embodiment of the low-temperature compressed air supply system of the present invention, there is provided a low-temperature compressed air supply system that dehumidifies and cools compressed air supplied from an air compressor to discharge dry low-temperature air, the system including a heatless dryer which is an adsorption-type dehumidifier that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified dry compressed air, a drying and cooling system unit that includes a first cooler that cools the dry compressed air supplied from the heatless dryer, and a second cooler that further cools the cooled dry compressed air supplied from the first cooler, and a control device that controls the switching timing of the two adsorption cylinders of the heatless dryer to be delayed by a certain time when the flow rate of the compressed air flowing through the drying and cooling system unit exceeds the rated flow rate at the switching timing of the two adsorption cylinders of the heatless dryer.
In addition, according to one embodiment of the low-temperature compressed air supply device system of the present invention, a flow rate sensor for detecting a flow rate can be provided on the side of the inlet part that supplies dry compressed air to the second cooler.

In addition, according to one embodiment of the low-temperature compressed air supply method of the present invention, the method dehumidifies and cools compressed air supplied from an air compressor to discharge dry low-temperature air, and is characterized in that the method includes a heatless dryer, which is an adsorption-type dehumidification device that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified dry compressed air, a first cooler that cools the dry compressed air supplied from the heatless dryer, and a second cooler that further cools the cooled dry compressed air supplied from the first cooler, and in the drying and cooling system section, when the flow rate of the compressed air flowing through the drying and cooling system section exceeds the rated flow rate, the flow rate is adjusted to the rated flow rate.

In addition, according to one embodiment of the low-temperature compressed air supply method of the present invention, the method dehumidifies and cools compressed air supplied from an air compressor to discharge dry low-temperature air, and is characterized in that the method includes a heatless dryer, which is an adsorption-type dehumidification device that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified dry compressed air, a first cooler that cools the dry compressed air supplied from the heatless dryer, and a second cooler that further cools the cooled dry compressed air supplied from the first cooler, and in the drying and cooling system section, when the flow rate of the compressed air flowing through the drying and cooling system section exceeds the rated flow rate, the set temperature of the second cooler is increased.

In addition, according to one embodiment of the low-temperature compressed air supply method of the present invention, the low-temperature compressed air supply method dehumidifies and cools compressed air supplied from an air compressor to discharge dry low-temperature air, and is characterized in that the method includes a heatless dryer, which is an adsorption-type dehumidification device that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified dry compressed air, a first cooler that cools the dry compressed air supplied from the heatless dryer, and a second cooler that further cools the cooled dry compressed air supplied from the first cooler, and when the flow rate of the compressed air flowing through the drying and cooling system exceeds the rated flow rate at the switching timing for the two adsorption cylinders of the heatless dryer, the switching timing for the two adsorption cylinders of the heatless dryer is delayed by a certain time.

The low-temperature compressed air supply system and low-temperature compressed air supply method according to the present invention have the special advantageous effect of being able to protect the system while continuing operation even if the compressed air flow rate increases above the rated flow rate due to a sudden change in the intake conditions or load fluctuation.

1 is a circuit diagram showing an example of a low-temperature compressed air supply system according to the present invention. FIG. 1 is a circuit diagram showing an example of a heatless dryer according to the present invention. 2 is a time chart illustrating an example of the operation of the heatless dryer of FIG. 1 .

Hereinafter, examples of a low-temperature compressed air supply system and a low-temperature compressed air supply method according to the present invention will be described in detail with reference to the attached drawings (Figs. 1 to 3). This low-temperature compressed air supply system dehumidifies and cools compressed air supplied from an air compressor, and discharges dry low-temperature air.

First, in the low-temperature compressed air supply system and low-temperature compressed air supply method related to the present invention, an invention for controlling the drying and cooling system section 200 to reduce energy consumption (hereinafter referred to as "energy saving") in the low-temperature compressed air supply system will be described with reference to FIG. 1.

The low-temperature compressed air supply system related to the present invention is basically configured to include a heatless dryer 1, which is an adsorption-type dehumidifier that dehumidifies compressed air by alternately switching between two adsorption cylinders 10, 20 (see Figure 2) filled with an adsorbent and continuously discharges the dehumidified dry compressed air, and a drying and cooling system section 200 that includes a first cooler 2 that cools the dry compressed air supplied from the heatless dryer 1, and a second cooler 3 that further cools the cooled dry compressed air supplied from the first cooler 2.

The first configuration for energy conservation includes a control device 50 that controls the cooling by the first cooler to stop or reduce the cooling when the temperature of the compressed air supplied to the drying and cooling system section 200 is lower than a reference temperature, or when the flow rate of the compressed air discharged as product air falls below a reference flow rate.

This low-temperature compressed air supply system and method can appropriately respond to changes in external environmental conditions, such as weather conditions and the environmental conditions under which the product air is used, and reduce energy consumption for system operation. That is, if the inlet air temperature is low, it is determined that the sensible heat load is low, and if the flow rate is low, it is determined that the load is low, and energy can be saved by stopping or reducing the operation of the first cooler.

The drying and cooling system section 200 according to the present invention is connected to a compressed air supply source 100 that supplies compressed air to the air inlet section, and a cooling water source 300 can be connected to the first cooler 2 and the second cooler 3 provided in the drying and cooling system section 200 as an example of a means for cooling the respective condensers 2b and 3b.

The compressed air supply source 100 may be, for example, a compressor that generates compressed air, a compressed air dehumidifier that dehumidifies the compressed air by condensing the moisture contained in the compressed air and discharging it as drain, or a device that includes an air pressure tank as components.
In addition, the ultra-low temperature dried air, which is the product air generated by this low temperature compressed air supply device system, is configured to be discharged from the drying and cooling system section 200 so as to be supplied to the low temperature compressed air utilization equipment 400.

In addition, the first cooler 2 and the second cooler 3 in this embodiment are devices that perform cooling by a refrigeration cycle, and the compressed air is cooled by the first heat exchanger 2a and the second heat exchanger 3a, and the compressed air at an ultra-low temperature, for example, adjusted to -35°C, can be supplied to the low-temperature compressed air utilization facility 400. In this embodiment, the cooling water 9 is introduced from an external cooling water source 300, and the first water-cooled condenser 2b of the first cooler 2 and the second water-cooled condenser 3b of the second cooler 3 are cooled by the water-cooled refrigeration cycle system. Of course, the coolers 2 and 3 using this refrigeration cycle can be air-cooled refrigeration cycle systems. In this embodiment, 3c is a dew point sensor, which is a component of the second cooler 3 and is provided to slightly purge air in order to measure the dew point. Furthermore, 3d is an air purge valve that is installed so that it can be purged appropriately if there is an excess of the product air, low-temperature compressed air, supplied to the low-temperature compressed air utilization equipment 400.

Next, the second configuration for energy saving is equipped with a control device 50 that controls the switching time interval between the two adsorption cylinders 10, 20 of the heatless dryer 1 to be extended when the dew point of the compressed air supplied to the drying and cooling system section 200 is lower than a reference dew point, or when the flow rate of the compressed air discharged as product air is lower than a reference flow rate.

This low-temperature compressed air supply system and method can appropriately respond to changes in external environmental conditions, such as weather conditions and the environmental conditions under which the product air is used, and reduce energy consumption for system operation. That is, if the inlet dew point is low, it is determined that the moisture load at the system inlet is low, and if the flow rate is low, it is determined that the load is low, and energy can be saved by extending the switching time of the heatless dryer. In other words, extending the switching time of the heatless dryer mainly reduces the amount of compressed air exhausted by purging in the adsorbent regeneration process, resulting in energy savings.

In addition, in this embodiment, a temperature sensor that detects temperature and a dew point sensor that detects dew point (temperature dew point sensor 6) are installed on the side of the intake section that supplies compressed air to the drying and cooling system section 200. This allows the condition of the compressed air supplied to the drying and cooling system section 200 to be properly confirmed, and the components of the drying and cooling system section 200 can be appropriately controlled to respond appropriately to changes in the outside world, such as weather conditions, and to reduce energy consumption for operating the system, as described above. In this embodiment, the control device 50 receives information from the temperature dew point sensor 6 installed as described above, and the control device transmits operation commands to each device according to preset conditions, enabling energy-saving operation.

In this embodiment, the flow sensor 7 that detects the flow rate is installed on the side of the air inlet that supplies dry compressed air to the second cooler. This allows the flow sensor 7 to be installed at the most downstream side of the system within the range that meets the cold resistance performance of a normal flow sensor 7. This allows the final required product air flow rate to be measured under better conditions, and appropriate control can be performed based on the measurement data. In this embodiment, the control device 50 receives information from the flow sensor 7 installed as described above, and the control device 50 transmits operation commands to each device according to preset conditions, enabling energy-saving operation.

Next, in the low-temperature compressed air supply system and low-temperature compressed air supply method according to the present invention, an invention for controlling the drying and cooling system section 200 to continue operating and protect the low-temperature compressed air supply system when the flow rate of the compressed air flowing through the drying and cooling system section 200 exceeds the rated flow rate will be described with reference to FIG. 1.

The low-temperature compressed air supply system, which is used when the rated flow rate is exceeded, is basically configured to include a heatless dryer 1, an adsorption-type dehumidifier that dehumidifies compressed air by alternately switching between two adsorption cylinders 10, 20 (see Figure 2) filled with an adsorbent and continuously discharges the dehumidified dry compressed air, a first cooler 2 that cools the dry compressed air supplied from the heatless dryer 1, and a second cooler 3 that further cools the cooled dry compressed air supplied from the first cooler 2.

The first configuration for continuing operation and protecting the low-temperature compressed air supply system includes a flow control valve 8 that adjusts the flow rate of the compressed air flowing through the drying and cooling system section 200 to the rated flow rate when the flow rate exceeds the rated flow rate, and a control device 50 that controls the flow control valve 8.

According to the low-temperature compressed air supply system and low-temperature compressed air supply method of the present invention, even if the compressed air flow rate exceeds the rated flow rate due to a sudden change in the intake conditions or load fluctuation, the system can continue to operate and be protected. In other words, if the flow rate exceeds the rated flow rate, the flow control valve is adjusted to the rated flow rate, so that the system can continue to operate without an alarm being issued and the second cooler 3, which is the ultra-low-temperature compressed air cooling device, can be prevented from being overloaded and damage to the filter elements due to an increase in the pressure difference between the filters (such as the first filter 4 and the second filter 5) when the air volume increases.

In this embodiment, the flow control valve 8 is installed on the side of the discharge section that discharges the product air from the second cooler 3. This allows the flow control valve 8 to be located immediately before the section that connects to the low-temperature compressed air utilization equipment 400 that supplies the product air, making it possible to more accurately control the flow rate of the product air.

The second configuration for continuing operation and protecting the low-temperature compressed air supply system includes a control device that controls the second cooler to increase its set temperature when the flow rate of the compressed air flowing through the drying and cooling system exceeds the rated flow rate.

According to the low-temperature compressed air supply system and the low-temperature compressed air supply method of the present invention, even if the compressed air flow rate exceeds the rated flow rate due to a sudden change in the inlet air condition or load change, operation can be continued. That is, in this invention, when the load of the heatless dryer 1 and the first cooler 2 increases with an increase in the flow rate, the inlet dew point of the second cooler 3 increases due to the increase in the load of the heatless dryer 1, and in order to prevent the second heat exchanger 3a built into the second cooler 3 from freezing, the set temperature is increased and the outlet temperature is controlled to be equal to or higher than the dew point temperature. According to this, even if the flow rate exceeds the rated flow rate, the set temperature of the second cooler 3, which is an ultra-low-temperature compressed air cooling device, is automatically changed according to the measured flow rate, so that the system can continue operation without an alarm stop. Note that this control is executed within an allowable range on the side of the low-temperature compressed air utilization equipment 400, and functions effectively when a range in which operation is possible is set, even if it is not the optimal condition, and operation can be continued.

The third configuration for continuing operation and protecting the low-temperature compressed air supply system includes a control device 50 that controls the switching timing of the two adsorption cylinders 10 and 20 of the heatless dryer to be delayed by a certain time when the flow rate of the compressed air flowing through the drying and cooling system exceeds the rated flow rate at the switching timing of the two adsorption cylinders 10 and 20 of the heatless dryer.

According to the low-temperature compressed air supply system and the low-temperature compressed air supply method of the present invention, even if the compressed air flow rate exceeds the rated flow rate due to a sudden change in the intake air conditions or load change, the system can be protected while continuing operation. In other words, if the flow rate exceeds the rated flow rate at the timing of switching the adsorption tubes 10 and 20 of the heatless dryer 1, the switching timing of the heatless dryer 1 can be delayed for a certain time, so that the system can continue operation without an alarm stop, and the flow rate can be prevented from increasing at the timing of switching the adsorption tubes 10 and 20, and damage to the filter elements due to an increase in the differential pressure of the filters (such as the first filter 4 and the second filter 5) when the air volume increases can be prevented. This also ensures that the second filter 5 functions reliably, and prevents leakage of the adsorbent from the heatless dryer 1.

In the above embodiment in which the switching timing of the heatless dryer 1 is delayed for a certain period of time, if the flow rate exceeds the rated flow rate even after the certain period of time has elapsed, and there are no serious problems with other conditions, the adsorption columns 10 and 20 are switched. This is because the dew point would rise if the adsorption columns 10 and 20 were not switched.

Incidentally, the phenomenon of the flow rate increasing at the timing of switching between the two adsorption columns 10, 20 is due to a primary increase in the amount of air discharged as product air, as shown in steps (1), (3), and (1)' in Figure 3, at the end of the adsorbent pressurization process when pressurization is completed and before switching occurs in each adsorption column 10 or 20, as there is no air to be purged and exhausted or used for pressurization.
Therefore, delaying the switching timing of the heatless dryer 1 by a certain period of time means extending a process that includes an exhaust process in which exhaust is performed by purging in either the adsorption column 10 or 20, as shown in steps (2), (4), or (4)' in Figure 3, and delaying the switching timing by a certain period of time.

Next, an example of the heatless dryer (compressed gas component adjustment device) of the contents of the application in Japanese Patent Application No. 2021-144449 that can be applied to the present invention will be described in detail with reference to Figures 2 and 3. The compressed gas component adjustment device according to the present invention adjusts the gas components of the compressed gas by alternately using two adsorption cylinders 10, 20 filled with an adsorbent, and continuously discharges the adjusted gas with the adjusted gas components, and has the following configuration.

This compressed gas component adjustment device is equipped with a first adsorption tube 10 and a second adsorption tube 20 filled with an adsorbent that adsorbs the required components of the introduced compressed gas. In FIG. 2, the first adsorption tube 10 is labeled "CLM A" and the second adsorption tube 20 is labeled "CLM B". The adsorbent in this embodiment adsorbs moisture from the air and discharges dry air as product air, and is an adsorption-type dehumidification device as described in the Background Art section, but the present invention is not limited to this, and it is of course possible to use an adsorbent that can selectively adsorb other gas components other than moisture (water vapor). Accordingly, the present invention can be suitably applied as a compressed gas component adjustment device that functions to remove a required gas component and increase the concentration of the required gas component.

In addition, in this embodiment, as shown in FIG. 2, the gas passages include a first gas supply passage 11 that guides compressed gas to the first adsorption cylinder 10, a second gas supply passage 21 that guides compressed gas to the second adsorption cylinder 20, a first discharge passage 13 that discharges the adjusted gas from the first adsorption cylinder 10, and a second discharge passage 23 that discharges the adjusted gas from the second adsorption cylinder 20, an adsorption cylinder connection passage 33 that connects the first adsorption cylinder 10 and the second adsorption cylinder 20, a first exhaust passage 15 through which a portion of the adjusted gas adjusted in the second adsorption cylinder 20 is guided to the first adsorption cylinder 10 via the adsorption cylinder connection passage 33 to desorb and purge the required components from the adsorbent and exhaust the gas to regenerate the adsorbent, and a second exhaust passage 25 through which a portion of the adjusted gas adjusted in the first adsorption cylinder 10 is guided to the second adsorption cylinder 20 via the adsorption cylinder connection passage 33 to desorb and purge the required components from the adsorbent and exhaust the gas to regenerate the adsorbent.

As shown in FIG. 2, the connection path 33 between the adsorption cylinders is provided with an orifice 34, which acts to obtain a predetermined constant flow rate by applying a predetermined constant pressure. Therefore, in this embodiment, when the first exhaust passage 15 or the second exhaust passage 25 is opened and the first adsorption cylinder 10 or the second adsorption cylinder 20 is opened to the atmosphere, the amount of air passing through the orifice 34 is automatically controlled to a constant flow rate due to the pressure difference between the inside of the first adsorption cylinder 10 or the second adsorption cylinder 20 opened to the atmosphere and the compressed gas supplied.

In addition, in this embodiment, as shown in FIG. 2, the components of the valve mechanism of the "switching valve (see FIG. 3)" that opens and closes the supply passages 11 and 12 of the above-mentioned gas passages include a first supply valve 12 that opens and closes the first supply passage 11, a second supply valve 22 that opens and closes the second supply passage 21, and an air supply valve opening and closing means 30 that operates to open and close the first supply valve 12 and the second supply valve 22. In the embodiment shown in FIG. 2, the first supply valve 12 and the second supply valve 22 are configured as control valves (CTV), and the air supply valve opening and closing means 30 is configured as a pilot valve (PV1).

In addition, in this embodiment, as shown in FIG. 2, the components of the valve mechanism of the "exhaust valve (see FIG. 3)" that opens and closes the exhaust passages 15 and 25 of the above-mentioned gas passages include a first exhaust valve 16 that opens and closes the first exhaust passage 15, a second exhaust valve 26 that opens and closes the second exhaust passage 25, a first exhaust valve opening and closing device 17 that operates to open and close the first exhaust valve 16, and a second exhaust valve opening and closing device 27 that operates to open and close the second exhaust valve 26. In the embodiment shown in FIG. 2, the first exhaust valve 16 and the second exhaust valve 26 are configured as exhaust valves (EXV), and the exhaust valve opening and closing means is configured by two pilot valves (PV2, PV3) arranged as the first exhaust valve opening and closing device 17 and the second exhaust valve opening and closing device 27.

In addition, the pilot valve (PV1) constituting the intake valve opening/closing means 30 in this embodiment, and the two pilot valves (PV2, PV3) constituting the first exhaust valve opening/closing device 17 and the second exhaust valve opening/closing device 27 are electromagnetically controlled valves, and operate as described in Patent Document 3. They are arranged so that the compressed gas supplied from the two adsorption cylinders 10, 20 operates the aforementioned control valve (CTV) and exhaust valve (EXV) to execute the aforementioned switching process.

In this embodiment, as shown in FIG. 2, a first pressure sensor 45 for monitoring the pressure in the first adsorption cylinder 10 and a second pressure sensor 46 for monitoring the pressure in the second adsorption cylinder 20 are provided. The first pressure sensor 45 (PS1) in this embodiment is attached to the downstream side where the adjustment gas (dry air in this embodiment) of the first adsorption cylinder 10 is discharged, and is attached to the pipe (air passage) before the orifice 34 of the adsorption cylinder connection passage 33, and is provided to measure and detect the pressure of the first adsorption cylinder 10 and output the detected pressure information to the control device 50 described later. The second pressure sensor 46 (PS2) in this embodiment is attached to the downstream side where the adjustment gas (dry air in this embodiment) of the second adsorption cylinder 20 is discharged, and is attached to the pipe (air passage) before the orifice 34 of the adsorption cylinder connection passage 33, and is provided to measure and detect the pressure of the second adsorption cylinder 20 and output the detected pressure information to the control device 50 described later.

In this embodiment, the control device 50 receives detected pressure information obtained by the first pressure sensor 45 and/or the second pressure sensor 46, compares the detected pressure information with a preset pressure based on a preset time period, and outputs a control signal or a warning signal to operate the intake valve opening/closing means 30 and the exhaust valve opening/closing means (the first exhaust valve opening/closing device 17 and the second exhaust valve opening/closing device 27) when the required conditions are met.

With the above configuration, the compressed gas component adjustment device according to the present invention has the particularly advantageous effect of monitoring the pressure changes inside the two adsorption tubes 10, 20 used in the pressure swing method in relation to the elapsed time, and more appropriately managing the operation of the device that performs the process related to adjusting the gas component of the compressed gas.

As shown in FIG. 2, the present embodiment includes the following components in addition to the above components.
Reference numeral 14 denotes a check valve (CKV(1)), which is installed so that the discharged regulated gas (dry air in this embodiment) does not flow back. Reference numeral 42 denotes a check valve (CKV(2)), which is installed so that the compressed gas supplied from the downstream of the two adsorption cylinders 10 and 20 to the pilot valve (PV1) and the two pilot valves (PV2, PV3) for control does not flow back. In FIG. 2, AF denotes an air filter, IF denotes an inlet filter, and OF denotes an outlet filter. In FIG. 2, SLC denotes a silencer, which serves as the exhaust port of the exhaust valve (EXV), and is arranged to reduce exhaust noise. Furthermore, MS denotes a temperature and humidity sensor.

Next, a specific embodiment of the control configuration of the control device 50 will be described with reference to FIG.
In this embodiment, as shown in FIG. 3 , the control device 50 sets two set times for increasing the pressure inside the first adsorption column 10 or the second adsorption column 20 by closing the first exhaust valve 16 or the second exhaust valve 26: a first pressure increase set time (<a> seconds) and a second pressure increase set time (<c> seconds) that is longer than the first pressure increase set time (<a> seconds).

And (X seconds) shown in FIG. 3 is the length of time it takes to actually reach the boost set pressure (in this embodiment, the pressure difference between the two adsorption tubes 10, 20 is, for example, 0 (±0.05) MPa or Δp). When the detected pressure information of the first pressure sensor 45 and/or the second pressure sensor 46 detects that the boost set pressure has been reached by the first boost set time (<a> seconds), a control signal is output by the control device 50 to operate the intake valve opening/closing means 30 and the exhaust valve opening/closing means (the first exhaust valve opening/closing device 17 or the second exhaust valve opening/closing device 27) at the time when the first boost set time (<a> seconds) is reached to switch between intake and exhaust. Note that this boost set pressure may be the differential pressure calculated by the detected pressure information of the first pressure sensor 45 and the second pressure sensor 46, or may be the pressure (Δp) set individually for the detected pressure information of the first pressure sensor 45 or the second pressure sensor 46, for example, when the intake pressure supplied to the compressed gas component adjustment device is stable. As an example of this operation, for example, in the time chart of FIG. 3, when the actual elapsed time (X seconds) in the second adsorption column 20 (column B) at the time of transition from process (1) to (2) becomes the same as the first boost setting time (<a> seconds), the air intake valve opening/closing means 30 opens the second air intake valve 22 to switch the air intake from the first adsorption column 10 (column A) to column B 20, thereby starting the adsorption process in column B 20, and in column A 10, the first exhaust valve opening/closing device 17 opens the first exhaust valve 16 to start the exhaust process.

In addition, when the detected pressure information of the first pressure sensor 45 and/or the second pressure sensor 46 detects that the boost set pressure (differential pressure of 0 (±0.05) MPa, or Δp) has been reached between the first boost setting time (<a> seconds) and the second boost setting time (<c> seconds), a control signal is output by the control device 50 at the time of detection to operate the intake valve opening/closing means 30 and the first exhaust valve opening/closing device 17 or the second exhaust valve opening/closing device 27 to switch between intake and exhaust. As an example of this operation, for example, in the time chart of Figure 3, when the actual elapsed time (X seconds) in cylinder B 20 at the time of transition from step (1)' to (2)' becomes longer than the first boost setting time (<a> seconds), the second air intake valve 22 is opened by the air intake valve opening/closing means 30 to switch the air intake from cylinder A 10 to cylinder B 20 at that time (X seconds), starting the adsorption process in cylinder B 20, and the first exhaust valve opening/closing device 17 opens the first exhaust valve 16 in cylinder A 10 to start the exhaust process. Note that in the time chart of Figure 3, when transitioning from step (3) to (4), the operations of cylinder A 10 and cylinder B 20 are reversed, but the same switching operation as above is performed.

Furthermore, if the detected pressure information of the first pressure sensor 45 and/or the second pressure sensor 46 does not detect that the boost set pressure (differential pressure of 0 (±0.05) MPa, or Δp) has been reached by the second boost set time (<c> seconds), the control device 50 outputs a control signal to forcibly operate the intake valve opening/closing means 30 and the first exhaust valve opening/closing device 17 or the second exhaust valve opening/closing device 27 to switch between intake and exhaust at the time when the second boost set time (<c> seconds) is reached. As an example of this operation, in the time chart of FIG. 3, if the set pressure (Δp) is not reached in cylinder A 10 at the time of transition from process (3)' to (4)' even after the second boost setting time (<c> seconds), at that time (<c> seconds), the first air intake valve 12 is opened by the air intake valve opening/closing means 30 to switch the air intake from cylinder B 20 to cylinder A 10, thereby starting the adsorption process in cylinder A 10, and in cylinder B 20, the second exhaust valve opening/closing device 27 opens the second exhaust valve 26 to start the exhaust process.

The above switching operation for the pressure increase process allows for smooth switching as described above, preventing the powdering (deterioration) of the adsorbent due to pressure fluctuations and the breakdown of valves.

Furthermore, in this embodiment, the control device 50 compares the value of the step-down set pressure (Δp) with the detected pressure information of the first pressure sensor 45 or the second pressure sensor 46, which is provided to monitor the pressure in the first adsorption tube 10 or the second adsorption tube 20, and outputs an alarm signal to issue an alarm if the pressure in the first adsorption tube 10 or the second adsorption tube 20 does not drop to the value of the step-down set pressure (Δp) even after a preset step-down set time (<b> seconds) has elapsed since the start of exhaust in the exhaust process, which is set as the time for the pressure in the first adsorption tube 10 or the second adsorption tube 20 to drop to the value of the step-down set pressure (Δp).

As an example of the operation by this, for example, in the time chart of Figure 3, as shown in step (4)', in cylinder B 20, when the set pressure drop time (<b> seconds) has elapsed and the set pressure drop (Δp) has not been reached, and the actual time drop (Y seconds) is longer than the set pressure drop time (<b> seconds), an alarm signal is output by the control device 50 to issue an alarm. This can improve reliability and operating efficiency as described above.

According to the compressed gas component adjustment device (heatless dryer) described above, by applying the control method of the control device 50, it is possible to control the low-temperature compressed air supply system shown in Figure 1 to extend the switching time interval between the two adsorption tubes 10 and 20 of the heatless dryer 1, or to delay the switching timing between the two adsorption tubes 10 and 20 of the heatless dryer 1 by a certain period of time.

The present invention has been described above in various preferred embodiments, but the present invention is not limited to these embodiments, and many modifications can be made without departing from the spirit of the invention.

REFERENCE SIGNS LIST 1 Heatless dryer 2 First cooler 2a First heat exchanger 2b First water-cooled condenser 3 Second cooler 3a Second heat exchanger 3b Second water-cooled condenser 3c Dew point sensor 3d Air purge valve 4 First filter 5 Second filter 6 Temperature dew point sensor 7 Flow rate sensor 8 Flow rate control valve 9 Cooling water 10 First adsorption column (column A)
11 First air supply passage 12 First air supply valve 13 First discharge passage 14 Check valve (CKV (1))
15 First exhaust passage 16 First exhaust valve 17 First exhaust valve opening/closing device (pilot valve (PV2))
20 Second adsorption cylinder (B cylinder)
21 Second air supply passage 22 Second air supply valve 23 Second discharge passage 25 Second exhaust passage 26 Second exhaust valve 27 Second exhaust valve opening/closing device (pilot valve (PV3))
30 Air supply valve opening/closing means (pilot valve (PV1))
33 Adsorption cylinder inter-connection path 34 Orifice 42 Check valve (CKV (2))
45 First pressure sensor 46 Second pressure sensor 50 Control device 100 Compressed air supply source 200 Drying and cooling system section 300 Cooling water source 400 Low-temperature compressed air utilization facility

Claims (8)

A low-temperature compressed air supply system that dehumidifies and cools compressed air supplied from an air compressor to discharge dry low-temperature air,
A heatless dryer is an adsorption-type dehumidification device that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified, dry compressed air.
a first cooler for cooling the dry compressed air supplied from the heatless dryer;
a second cooler that further cools the cooled, dry compressed air supplied from the first cooler;
a flow control valve that adjusts the flow rate of the compressed air flowing through the drying and cooling system to the rated flow rate when the flow rate of the compressed air flowing through the drying and cooling system exceeds a rated flow rate;
and a control device for controlling the flow control valve. The low-temperature compressed air supply system according to claim 1, characterized in that the flow control valve is installed on the side of the discharge portion that discharges product air from the second cooler. A low-temperature compressed air supply system that dehumidifies and cools compressed air supplied from an air compressor to discharge dry low-temperature air,
A heatless dryer is an adsorption-type dehumidification device that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified, dry compressed air.
a first cooler for cooling the dry compressed air supplied from the heatless dryer;
a second cooler that further cools the cooled, dry compressed air supplied from the first cooler;
A low-temperature compressed air supply system comprising a control device that controls the set temperature of the second cooler to be increased when the flow rate of the compressed air flowing through the drying cooling system section exceeds a rated flow rate. A low-temperature compressed air supply system that dehumidifies and cools compressed air supplied from an air compressor to discharge dry low-temperature air,
A heatless dryer is an adsorption type dehumidification device that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified, dry compressed air.
a first cooler for cooling the dry compressed air supplied from the heatless dryer;
a second cooler that further cools the cooled, dry compressed air supplied from the first cooler;
A low-temperature compressed air supply system comprising a control device that controls the switching timing for the two adsorption cylinders of the heatless dryer to be delayed by a certain period of time when the flow rate of the compressed air flowing through the drying and cooling system exceeds the rated flow rate at the switching timing for the two adsorption cylinders of the heatless dryer. A low-temperature compressed air supply system according to any one of claims 1 to 4, characterized in that a flow rate sensor for detecting the flow rate is provided on the side of the inlet that supplies dry compressed air to the second cooler. A method for supplying low-temperature compressed air, comprising the steps of: dehumidifying and cooling compressed air supplied from an air compressor to discharge dry low-temperature air,
A heatless dryer is an adsorption-type dehumidification device that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified, dry compressed air.
a first cooler for cooling the dry compressed air supplied from the heatless dryer;
a second cooler that further cools the cooled, dry compressed air supplied from the first cooler,
A method for supplying low-temperature compressed air, characterized in that when the flow rate of the compressed air flowing through the drying and cooling system exceeds a rated flow rate, the flow rate is adjusted to the rated flow rate. A method for supplying low-temperature compressed air, comprising the steps of: dehumidifying and cooling compressed air supplied from an air compressor to discharge dry low-temperature air,
A heatless dryer is an adsorption-type dehumidification device that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified, dry compressed air.
a first cooler for cooling the dry compressed air supplied from the heatless dryer;
a second cooler that further cools the cooled, dry compressed air supplied from the first cooler,
A method for supplying low-temperature compressed air, comprising the steps of: increasing a set temperature of the second cooler when a flow rate of the compressed air flowing through the drying and cooling system exceeds a rated flow rate. A method for supplying low-temperature compressed air, comprising the steps of: dehumidifying and cooling compressed air supplied from an air compressor to discharge dry low-temperature air,
A heatless dryer is an adsorption-type dehumidification device that dehumidifies compressed air by alternately switching between two adsorption cylinders filled with an adsorbent and continuously discharges the dehumidified, dry compressed air.
a first cooler for cooling the dry compressed air supplied from the heatless dryer;
a second cooler for further cooling the cooled dry compressed air supplied from the first cooler,
A method for supplying low-temperature compressed air, characterized in that when the flow rate of the compressed air flowing through the drying and cooling system section exceeds the rated flow rate at the switching timing for the two adsorption cylinders of the heatless dryer, the switching timing for the two adsorption cylinders of the heatless dryer is delayed by a certain period of time.

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