JPS633028B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steam cleaning method, in particular, which accelerates the drying of objects to be cleaned, such as metals, after steam cleaning with an organic solvent, etc. The purpose of the present invention is to provide a steam cleaning method suitable for preventing loss of organic solvent due to leakage.

The steam cleaning method has many features, such as the ability to clean and dry the object to be cleaned in one step, and the fact that the object to be cleaned is generally dried in organic solvent vapor, resulting in a clean finished surface. It is used as a finishing process for various metal products including stainless steel products. Conventionally, devices used for steam cleaning generally have a structure in which, for example, a heater is provided at the bottom of a tank with an open top surface, and a condenser is provided around the opening in the top surface. However, such steam cleaning apparatuses have many problems when used alone or in conjunction with other cleaning processes such as spray cleaning for continuous cleaning of objects to be cleaned. That is, in the above-mentioned apparatus, the object to be cleaned is cleaned by condensing the solvent vapor on the surface of the object in a tank in which vapor of an organic solvent evaporated by a heater is present, and then the temperature of the object to be cleaned is increased. When the object reaches the steam temperature, it is dried and taken out from the tank, but it takes a considerable amount of time for the object to be cleaned to reach the steam temperature. For this reason, methods have been adopted in which the items to be cleaned are moved slowly and continuously in a tank of a steam cleaning device and steam cleaning is performed within the tank, but this method has the problem of making it difficult to increase the processing speed. Was. In addition, in order to increase the processing speed, it is possible to extend the contact area between the steam and the object by extending the tank of the steam cleaning equipment in the direction of movement of the object to be cleaned. Since the area of the part increases, a problem arises in that the amount of leakage of steam containing organic solvent increases.
In addition, the above-mentioned steam cleaning apparatus requires means for moving and raising and lowering the object to be cleaned in order to take it in and out of the tank, so it also has the problem of complicating the mechanism for transporting the object to be cleaned. have

As a result of consideration in view of the above problems, the present inventors found that
A steam cleaning device with the novel structure described above has already been proposed. That is, a means for transporting the object to be cleaned is provided in a cylindrical body with openings at both ends, and a vapor supply means is provided in the body of the cylindrical body to supply vapor of an organic solvent. By installing a condenser in the pipe, it is possible to extend the length of the body, that is, the contact area between the steam and the object to be cleaned, without affecting the amount of steam leakage. This is a steam cleaning device that can flatten the transfer line and eliminate the complexity of the transfer mechanism. Since this apparatus solves the problems of the conventional steam cleaning apparatus as described above, it is suitable for processing large quantities of large objects to be cleaned with complex shapes, such as sinks, for example.

The present inventors have studied methods for further increasing the processing speed and increasing the solvent recovery rate using the above-mentioned steam cleaning apparatus, and as a result, have provided the steam cleaning method of the present invention.

That is, the present invention provides a cylindrical body with both ends open, a means for transferring the object to be cleaned from one end to the other, and a steam cleaning section in the body of the cylindrical body and openings at both ends. When steam cleaning an object to be cleaned in a steam cleaning device that has a condensation section on the inner wall, at least a portion of the gas inside the cylindrical body is extracted to the outside of the steam cleaning device and transferred to the steam cleaning device via a steam recovery device. This is a steam cleaning method characterized by recirculation to the condensing section.

After steam cleaning in the above steam cleaning equipment,
In order to speed up the drying (condensation) of the object to be cleaned,
This can also be achieved by simply blowing air into the condensing section of the device from the outside. However, according to such a method, the amount of steam leaking from the openings at both ends of the cylindrical body increases due to the introduced outside air, so it is necessary to use a large capacity gas suction means such as a compressor or blower. There is a problem that must be solved. On the other hand, the object to be cleaned that has been dried in the condensing section of the steam cleaning device is taken out as a product from the end of the cylindrical body, but at this time, the object to be cleaned is accompanied by steam corresponding to the atmospheric temperature of the condensing section. Therefore, if the product is taken out of the steam cleaning apparatus as it is, there will be a problem in that the solvent vapor will leak into the atmosphere and the solvent will be lost. The most common method to solve the above problem is to increase the capacity of the condensing section in the steam cleaning device to increase the condensation speed, and to provide suction ports at both ends of the cylindrical shape, and to use the steam through the steam recovery device. There is a method of exhausting the gas into the atmosphere. However, in this method, when the solvent is sucked by a blower or the like, outside air is mixed in, so it is inevitable that the means for sucking the gas and the vapor recovery device become larger. Furthermore, when the drying speed is slow, a cloud point is formed on the surface of the object to be cleaned, resulting in a problem that the finish of the product is impaired.

On the other hand, according to the present invention, a part of the gas in the condensing section is self-circulated via the vapor recovery device, so there is no need to increase the size of the device, the solvent recovery rate can be increased, and further processing is possible. You can also increase your speed.

The steam cleaning device used in the present invention is a cylindrical body with both ends open, and there is a means (hereinafter referred to as a transfer means) for transferring the object to be cleaned from one end to the other end in the cylindrical body. There is no particular restriction as long as the structure has a steam cleaning section at the opening and a condensing section at the inner wall of the opening at both ends. A typical example will be explained in detail with reference to FIG.

The cylindrical body 1 is open at both ends, and is not particularly limited as long as it has a cross-sectional area through which the object to be cleaned can pass by the transfer means described later. For example, the shape is generally cylindrical, prismatic, horseshoe, etc. Further, the length of the cylindrical body 1 may be appropriately determined in consideration of heat capacity such as processing speed and wall thickness of the object to be cleaned. Generally, it is preferable that the length be longer than the length necessary to raise the temperature of the object to be cleaned to the steam temperature within the cylindrical body. Furthermore, in order to prevent the supplied organic solvent vapor from being cooled and condensed on the inner wall surface, the cylindrical body 1 may be surrounded by a heat insulating material or may be made of a heat insulating material as the case may be. Therefore, it is preferable to provide a heating means in the cylindrical body. In particular, the temperature of the wall surface of the cylindrical body is
It is preferable to design so that the temperature is highest at the center or slightly closer to the inlet than the center. Further, the object to be cleaned transfer means 2 present in the cylindrical body 1 is capable of continuously transferring the object to be cleaned 3 from one end (also referred to as an inlet) to the other end (also referred to as an outlet) of the cylindrical body. Any known transportation device having a structure that can be used can be used without particular limitation.

Therefore, the transfer means does not need to be independently present only inside the cylindrical body, but may have a structure that penetrates through the cylindrical body as part of a production line for objects to be cleaned. For example, conveyors such as belt conveyors, net conveyors, coil conveyors, chain conveyors, etc. are common, and the equipment suitable for the shape and size of the object to be cleaned can be selected as appropriate.

Further, the body of the cylindrical body 1 includes a steam cleaning section 4,
There is a steam supply inlet 5 from steam supply means (not shown). The steam supply means may be used without particular limitation as long as it can supply a sufficient amount of steam to provide the steam concentration necessary for steam cleaning inside the cylindrical body. For example, a method (external supply method) in which an evaporator is provided near the steam cleaning device to generate steam and supply the steam from a steam supply section 5 consisting of a nozzle (external supply method) makes it easy to control the steam concentration. It is. Even when the body is long, it is preferable to increase the number of nozzles to uniformly supply steam to the entire body. Further, the bottom surface of the cylindrical body 1 is configured to serve as a condensate receiving tray, and is sloped as necessary so that the liquid flows toward the condensate outlet 6. The condensate is taken out from the outlet 6 and circulated to the evaporator via a condensate circulation pipe. Of course, the steam supply means is not limited to the external supply method as described above; for example, although not shown in the figure, a liquid reservoir is formed at the bottom of the cylindrical body, and a heater is attached to the liquid reservoir. A method is also adopted in which steam is supplied by providing a vaporizer to evaporate the organic solvent.

Furthermore, in order to dry the object to be cleaned after steam cleaning and to prevent the steam inside the cylindrical body 1 from leaking to the outside, the above apparatus is equipped with a cooling means 7 (and a condenser) on the inner wall of the opening at both ends. 7'). At this time, although the installation mode of the capacitors is shown in FIG. 1 as two systems in which two sets of capacitor groups are installed, the present invention is not particularly limited to this mode. As the cooling means, a known condenser or the like may be used without any particular restriction as long as it does not pose an obstacle to the transferred object to be cleaned. For example, it is common to attach a condenser of a flexible tube type, a plate type, etc. near the openings at both ends of the cylindrical body 1. In this case, it is effective to form a cooling surface on the entire inner periphery of the opening of the cylindrical body, but cooling means 7-b attached to the outlet side of the object to be cleaned
(or 7'-b), the liquid condensed on the top surface falls onto the object to be cleaned, causing the formation of a so-called cloud point, so a means must be provided to prevent the condensed liquid from falling. is preferred. For example, a mode in which a cooling surface is not present on the upper surface of the inner wall near the exit of the cylindrical body 1, a mode in which the upper surface is heated, a mode in which the upper surface is sloped,
It is preferable to use one or more of the following methods, such as a method in which the condensate flows along the surface and reaches the side wall of the cylindrical body, and a method in which an umbrella is provided above the object to be cleaned.
Among these, a mode in which no cooling means is provided on the upper surface of the inner wall of the cylindrical body is recommended because it is simple and has a high cloud point prevention rate.

In the present invention, when drying an object to be cleaned after steam cleaning using the above-mentioned steam cleaning apparatus, at least a part of the gas inside the cylindrical body is extracted to the outside of the apparatus,
It is characterized by being recirculated to the condensing section via a vapor recovery device, and the means for doing so is not particularly limited. For example, as shown in FIG. 1, a part of the gas in the cylindrical body 1, preferably in the condensing section 7 or 7' and on the outlet side near the condensing section, is sucked by a compressor or blower 8, and the sucked gas is The gas (generally air) introduced into the steam recovery device 9 and separated from the solvent is recycled to the condensing section of the steam cleaning device. The solvent after being separated into gas and liquid by the vapor recovery device 9 is collected in a solvent receiving tray 11 via a pipe 10. in this case,
In order to speed up the drying rate of the object to be cleaned, it is possible to heat the gas from which the solvent has been removed and recirculate it as necessary, or, as shown in Figure 1, two series of condensing sections are provided and each series is equipped with a cooling means. It is preferable to provide two sets of each, and to recirculate the gas using a plurality of blowing nozzles 12 and 13. In the latter method, the type of cooling water that is circulated to each condensing section is changed (for example, using ordinary inexpensive cooling water for 7-b and 7'-a, and using cold water or brine for 7-a and 7'-b). In addition to making it easy to control the cooling temperature, multiple blow nozzles are used to recirculate the gas, which can be used to blow off solvent droplets that have adhered to the surface of the object to be cleaned. Since it can be used separately for the purpose of replacing the solvent vapor on the surface of the object to be cleaned with a gas that does not contain the solvent, the drying speed can be further increased.

As the above-mentioned vapor recovery device 9, various well-known methods can be used, such as a method of separating gas and liquid using a condenser, an adsorption method using an adsorbent such as activated carbon, etc., but using a compressor as a gas circulation device,
When pressurizing the gas, it is preferable because it is possible to efficiently condense and separate the solvent vapor using a relatively small condenser using an inexpensive cooling source such as water.

The type (model), capacity, etc. of the blower, compressor, etc. used for the means 8 for extracting the gas inside the cylindrical body to the outside of the apparatus are appropriately selected depending on the volume of the cylindrical body 1, the shape of the object to be cleaned, the processing amount, etc. be done. At this time, the position of the suction port 14 connected to the blower 8 etc.
The suction port 14 is preferably attached to the condensing section or near the outlet of the condensing section, since the suction port 14 has a large influence on the suction of outside air and requires a large capacity of the blower.

In addition, the cleaning liquid in the present invention may include readily volatile liquids conventionally used as steam cleaning agents, such as ether, alcohol, methylene chloride,
Organic solvents such as dichloroethane, trichloroethane, and perchlorethylene, particularly chlorinated hydrocarbons, are preferably used, but other solvents such as water may also be used.

The apparatus of the present invention is suitably used for steam cleaning of various articles including metal workpieces. For example, metal products include metal plates, metal plate products, and metal parts such as metal screws, bolts, and nuts.

As an example of the present invention, a relatively high boiling point solvent,
For example, when using trichloroethane, perchlorethylene, etc., drying only in the condensing section without gas recirculation takes several tens of seconds to several minutes.
Because the drying speed is slow, cloud points occur on the surface of the object to be cleaned. In order to prevent this, it is necessary to increase (lengthen) the volume of the condensing section. On the other hand, if an appropriate amount of gas (heated if necessary) is sprayed onto the object to be cleaned, it can be dried in about a few seconds, and problems such as overscaling of the device and occurrence of clouding points as described above can be prevented. The amount of blown air is appropriately selected depending on the shape of the object to be cleaned, etc., but since this method also replaces solvent vapor with gas, in the case of an object to be cleaned that has a concave portion (has a vapor retention area), It is sufficient to introduce an amount 3 to 5 times the volume of the retention section.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a typical example of a steam cleaning device used in the present invention. In the figure, 1 is a cylindrical body, 2 is a transfer means, 3 is an object to be cleaned, 4 is a steam cleaning section, 5 is a steam supply section, 6 is a condensate outlet, 7 and 7' are condensation sections (7-a, 7-b, 7'-a, 7'-b are cooling means), 8 is a compressor or blower, 9 is a steam recovery device, 10 is piping, 11 is a melted saucer, 12 and 1
3 is a gas blowing nozzle, and 14 is a suction port.

Claims (1)

[Claims] 1 A cylindrical body with both ends open and a means for transferring the object to be cleaned from one end to the other, and a steam cleaning part in the body of the cylindrical body, and a steam cleaning part in the inner wall of the opening at both ends. When steam cleaning an object to be cleaned in a steam cleaning device having a structure with A steam cleaning method characterized by circulation.