JP7148975B2 - Steam cleaning/decompression drying equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a steam cleaning/vacuum drying apparatus that dries a workpiece under reduced pressure after cleaning it with steam.

Conventionally, a steam cleaning/vacuum drying apparatus has been used in which vacuum drying is performed to remove the cleaning liquid adhering to the workpiece after cleaning the workpiece using steam obtained by vaporizing the cleaning liquid (see, for example, Patent Document 1). In the steam cleaning/reduced pressure drying apparatus, first, a work is accommodated in a vacuum chamber, and then steam is introduced into the vacuum chamber. As a result, the steam comes into contact with the surface of the low-temperature workpiece and liquefies, cleaning the surface (steam cleaning). During this liquefaction, the steam exchanges heat with the work, and the work is heated. After the surface of the workpiece has been sufficiently cleaned and heated sufficiently, the supply of steam is stopped and the pressure in the vacuum chamber is reduced to evaporate the cleaning liquid adhering to the surface of the workpiece. Dry (vacuum drying).

After the steam cleaning is completed, the pressure inside the vacuum chamber is reduced, and the cleaning liquid remaining in the vapor state inside the vacuum chamber is discharged from the vacuum chamber and enters the vacuum pump, where it is cooled and condensed (liquefied). do. As a result, the operation of the vacuum pump is hindered, and the ability to depressurize the inside of the vacuum chamber is reduced. Therefore, conventionally, a condenser is provided between the vacuum tank and the vacuum pump, and the vapor is condensed by the condenser before the vapor reaches the vacuum pump (for example, "Conventional Techniques" in Patent Document 1). column). However, in this configuration, the cleaning liquid liquefied in the condenser evaporates when the pressure is reduced by the vacuum pump, so it is difficult to lower the pressure in the vacuum chamber below the vapor pressure of the cleaning liquid in the condenser.

Therefore, in the steam cleaning/reduced pressure drying apparatus described in Patent Document 1, after the steam cleaning is completed, the first step of sucking the steam in the vacuum chamber and returning it to the vacuum chamber via a condenser for condensing the steam is performed. After that, the second step of drying the workpiece under reduced pressure is performed by reducing the pressure in the vacuum chamber without passing through the condenser. According to this configuration, the pressure in the vacuum chamber can be lowered to the vapor pressure in the condenser in the first step, and then lowered to the capacity of the vacuum pump in the second step.

JP-A-11-030478

In the apparatus disclosed in Patent Document 1, since the steam in the condenser is returned to the vacuum chamber in the first step, the degree of vacuum in the vacuum chamber is slowed down.

As described above, the cleaning of the work in the vacuum chamber is performed as follows. First, a work is accommodated in a vacuum chamber, and then steam is introduced into the vacuum chamber. As a result, the steam comes into contact with the surface of the low-temperature workpiece and liquefies, cleaning the surface (steam cleaning). During this liquefaction, the steam exchanges heat with the work, and the work is heated. After the surface of the workpiece has been sufficiently cleaned and heated sufficiently, the supply of steam is stopped and the pressure in the vacuum chamber is reduced to evaporate the cleaning liquid adhering to the surface of the workpiece. Dry (vacuum drying). During this reduced-pressure drying, by rapidly decompressing, bumping occurs from inside the cleaning liquid adhering to the work surface, and drying can be accelerated (bumping drying).

However, the apparatus described in Patent Document 1 cannot perform such rapid depressurization, so bumping drying cannot be performed.

A problem to be solved by the present invention is to provide a steam cleaning/reduced pressure drying apparatus capable of quickly performing drying after steam cleaning.

The steam cleaning/reduced pressure drying apparatus according to the present invention, which has been made to solve the above problems,
a) a vacuum chamber in which the workpiece is hermetically contained;
b) a steam supply unit for supplying steam of the cleaning liquid into the vacuum chamber;
c) a vacuum pump whose exhaust port does not have a connection path with the vacuum chamber;
d) a first exhaust pipe connecting the vacuum chamber and the suction port of the vacuum pump;
e) a condenser provided in the middle of the first exhaust pipe;
f) a second exhaust pipe, which is provided separately from the first exhaust pipe and connects the vacuum chamber and the suction port of the vacuum pump;
g) A switching valve for switching an exhaust path between the vacuum chamber and the vacuum pump to either the first exhaust pipe or the second exhaust pipe.

In the vapor cleaning/reduced pressure drying apparatus according to the present invention, vapor cleaning is performed by storing the workpiece in the vacuum chamber and then supplying the vapor of the cleaning liquid from the vapor supply section into the vacuum chamber. After the surface of the work is sufficiently cleaned and the work is sufficiently heated, the supply of steam from the steam supply unit is stopped, and the work is dried under reduced pressure as follows.

First, the switching valve sets the exhaust path to the first exhaust pipe side. Then, the vapor of the cleaning liquid remaining in the vacuum chamber after cleaning is introduced from the vacuum chamber into the condenser, and most of it is condensed in the condenser. Therefore, the vapor of the cleaning liquid is prevented from condensing in the vacuum pump, and the deterioration of the ability to depressurize the inside of the vacuum chamber is prevented. The gas that has passed through the condenser is exhausted from the exhaust port through the vacuum pump through the intake port. Since this outlet is not connected to the vacuum chamber, the gas is discharged outside the vacuum chamber without being returned to the vacuum chamber. As a result, the inside of the vacuum chamber can be rapidly depressurized, and bumping can be generated from inside the cleaning liquid adhering to the surface of the workpiece, thereby promoting drying (bumping drying). In this manner, bumping drying is performed from the step of condensing the vapor of the cleaning liquid remaining in the vacuum chamber in the condenser, so that drying after vapor cleaning can be performed quickly.

If this operation is continued for a while, most of the steam remaining in the vacuum chamber after the completion of steam cleaning and the gas of the cleaning liquid vaporized from the work surface at the start of bumping drying will be discharged, and the Only the cleaning liquid remaining on the work surface without being fully vaporized is discharged. In that case, even if the gas discharged from the vacuum chamber is introduced directly into the vacuum pump without passing through the condenser, the operation of the vacuum pump is hardly hindered. Therefore, the switching valve switches the exhaust path to the second exhaust pipe side. As a result, the cleaning liquid liquefied in the condenser is prevented from evaporating due to the pressure reduction by the vacuum pump, and the pressure reduction in the vacuum chamber is promoted, so that the drying of the workpiece can be further promoted.

It is preferable that the steam cleaning/reduced pressure drying apparatus according to the present invention further include a heater for heating the inside of the second exhaust pipe. As a result, when the inside of the vacuum chamber is decompressed through the second exhaust pipe, the vapor of the cleaning liquid discharged from the vacuum chamber is heated within the second exhaust pipe. It becomes easy to pass through as it is, and it is possible to suppress liquefaction of the vapor in the vacuum pump. Therefore, it is possible to further suppress the deterioration of the ability to depressurize the inside of the vacuum chamber.

It is preferable that the steam cleaning and vacuum drying apparatus according to the present invention further include a cleaning liquid storage tank connected to the exhaust port (of the vacuum pump). As a result, the cleaning liquid that is not condensed in the condenser when the inside of the vacuum chamber is decompressed through the first exhaust pipe and the cleaning liquid discharged from the vacuum chamber when the inside of the vacuum chamber is decompressed through the second exhaust pipe are stored in the storage tank. It is possible to recover and prevent adverse effects on the environment around the steam cleaning/reduced pressure drying apparatus.

The steam cleaning/reduced pressure drying apparatus according to the present invention enables quick drying after steam cleaning.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram which shows one Embodiment of the steam cleaning and reduced-pressure drying apparatus which concerns on this invention. Schematic diagram showing the initial operation during vacuum drying in the steam cleaning/reduced pressure drying apparatus of the present embodiment. FIG. 4 is a schematic diagram showing the operation of the vapor cleaning/reduced pressure drying apparatus of the present embodiment in the latter stage of vacuum drying. The schematic block diagram which shows the modification of the steam cleaning and reduced-pressure drying apparatus of this embodiment.

An embodiment of a steam cleaning/reduced pressure drying apparatus according to the present invention will be described with reference to FIGS. 1 to 4. FIG.

(1) Structure of the steam cleaning/reduced pressure drying apparatus of the present embodiment As shown in FIG. , a vacuum pump 13 , a condenser 14 , a condenser side temporary storage tank 151 , a vacuum tank side temporary storage tank 152 and a storage tank 15 .

The vacuum chamber 11 and the steam generation chamber 12 are connected by a steam supply pipe 121 . The intake port 131 of the vacuum chamber 11 and the vacuum pump 13 is composed of two exhaust pipes: a first exhaust pipe 161 provided with the condenser 14 in the middle and a second exhaust pipe 162 provided without the condenser 14 . It is connected. The vacuum chamber 11 side of the first exhaust pipe 161 and the second exhaust pipe 162 is connected to the vacuum chamber 11 by a common vacuum chamber side connection pipe 1651 . The intake port 131 sides of the first exhaust pipe 161 and the second exhaust pipe 162 are connected to the intake port 131 by a common pump-side connection pipe 1652 . The exhaust port 132 of the vacuum pump 13 is connected by a third exhaust pipe 163 to the lower part of the storage tank 15 (below the liquid level of the cleaning liquid L stored in the storage tank 15, as described later), and the vacuum is It is not connected to tank 11 . A heater 18 is provided in the second exhaust pipe 162 .

The bottom of the condenser 14 and the condenser side temporary storage tank 151 are connected by a first cleaning liquid recovery pipe 171 , and the condenser side temporary storage tank 151 and the storage tank 15 are connected by a second cleaning liquid recovery pipe 172 . The bottom of the vacuum tank 11 and the vacuum tank side temporary storage tank 152 are connected by a third cleaning liquid recovery pipe 173 , and the vacuum tank side temporary storage tank 152 and the storage tank 15 are connected by a fourth cleaning liquid recovery pipe 174 . A liquid sending pump 1741 is provided in the fourth cleaning liquid recovery pipe 174 . Also, the vacuum tank side temporary storage tank 152 and the pump side connection pipe 1652 are connected by the vacuum tank side temporary storage tank exhaust pipe 164 .

The vacuum chamber 11 accommodates the workpiece W in an airtight manner. A lid 111 is provided on the upper surface of the vacuum chamber 11, and when the work W is carried into the vacuum chamber 11 and when the work W is unloaded from the vacuum chamber 11, the lid 111 is opened to perform steam cleaning and vacuum. By closing the lid 111 during drying, the inside of the vacuum chamber 11 can be sealed (airtight).

The steam generation tank 12 heats the cleaning liquid L to generate steam of the cleaning liquid L. As shown in FIG.

The vacuum pump 13 is a pump that exhausts the inside of the vacuum chamber 11 through either a first exhaust pipe 161 or a second exhaust pipe 162 as will be described later. Since the vacuum chamber 11 is airtight, when the inside is evacuated by the vacuum pump 13, the pressure inside decreases (the degree of vacuum increases).

The condenser 14 condenses (liquefies) the gas passing through it by cooling the gas.

The storage tank 15 stores the cleaning liquid L recovered from the inside of the vacuum tank 11 . Vapor (gas) of the cleaning liquid exhausted from the exhaust port 132 of the vacuum pump 13 is introduced into the storage tank 15 through the third exhaust pipe 163 and is absorbed by the liquid cleaning liquid L stored in the storage tank 15 . , which is recovered as a liquid. The gas not absorbed by the cleaning liquid L is discharged from a discharge port (not shown) provided in the storage tank 15 .

The condenser-side temporary storage tank 151 temporarily stores the cleaning liquid L collected from the vacuum chamber 11 that is condensed in the condenser 14 . As described above, the storage tank 15 is connected to the third exhaust pipe 163 and the second cleaning liquid recovery pipe 172 , the former of which is located below the liquid surface of the cleaning liquid L stored in the storage tank 15 . It is connected. The vacuum tank-side temporary storage tank 152 temporarily stores the cleaning liquid L liquefied in the vacuum tank 11 .

The heater 18 is provided on the outer circumference of the second exhaust pipe 162 and heats the gas passing through the inside of the second exhaust pipe 162 .

An on-off valve 1911 is located at a position closer to the vacuum chamber side connection pipe 1651 than the condenser 14 of the first exhaust pipe 161 , and an on-off valve 1912 is located at a position closer to the pump side connection pipe 1652 than the condenser 14 of the first exhaust pipe 161 . However, an on-off valve 1913 is located at a position closer to the vacuum chamber side connection pipe 1651 than the heater 18 of the second exhaust pipe 162, and an on-off valve 1914 is located at a position closer to the pump side connection pipe 1652 than the heater 18 of the second exhaust pipe 162. are provided respectively. These four on-off valves 1911 to 1914 are opened or closed as follows by a control unit (not shown). The on-off valves 1911 and 1912 are always opened or closed at the same time, and the on-off valves 1913 and 1914 are always opened or closed at the same time. When the on-off valves 1911 and 1912 are opened, the on-off valves 1913 and 1914 are closed, and when the on-off valves 1913 and 1914 are opened, the on-off valves 1911 and 1912 are closed. By these controls, the on-off valves 1911 and 1912 are opened (indicated by "O" in FIG. 2) and the on-off valves 1913 and 1914 are closed (indicated by "C" in FIG. 2), the vacuum chamber 11 and the vacuum pump 13 is on the side of the first exhaust pipe 161 (indicated by a thick line in FIG. 2). On the other hand, when the on-off valves 1913 and 1914 are open (indicated by "O" in FIG. 3) and the on-off valves 1911 and 1912 are closed (indicated by "C" in FIG. 3), the vacuum chamber 11 and the vacuum The exhaust path with the pump 13 is on the side of the second exhaust pipe 162 (indicated by a thick line in FIG. 3). In this way, the combination of these four on-off valves 1911 to 1914 switches the exhaust path between the vacuum chamber 11 and the vacuum pump 13 to either the first exhaust pipe 161 or the second exhaust pipe 162. It functions as valve 191 .

The steam supply pipe 121 is provided with a steam supply control valve 192 that supplies steam to the vacuum chamber 11 when opened and stops the supply of steam to the vacuum chamber 11 when closed. Further, the first cleaning liquid recovery pipe 171, the second cleaning liquid recovery pipe 172, the third cleaning liquid recovery pipe 173, and the fourth cleaning liquid recovery pipe 174 are provided with a first drain valve 1931 and a second drain valve 1932, which are opening/closing valves, respectively. , a third drain valve 1933 and a fourth drain valve 1934 are provided. The vacuum tank 11, the condenser 14, the condenser-side temporary storage tank 151, and the vacuum tank-side temporary storage tank exhaust pipe 164 are provided with atmosphere release valves 1941, 1942, 1943 for opening their interiors to the atmosphere (breaking the vacuum) and 1944 is provided. Further, the vacuum tank side temporary storage tank exhaust pipe 164 is provided with an open/close valve 195 for opening and closing the exhaust path between the vacuum tank side temporary storage tank 152 and the pump side connection pipe 1652 .

(2) Operation of Vapor Cleaning/Reduced-Pressure Drying Apparatus of this Embodiment Next, the operation of the steam cleaning/reduced-pressure drying apparatus 10 of this embodiment will be described.

(2-1) Vapor Cleaning First, the lid 111 of the vacuum chamber 11 is opened, and after the workpiece W is housed in the vacuum chamber 11, the lid 111 is closed. In this state, the steam supply control valve 192, the second drain valve 1932 and the fourth drain valve 1934 are closed, and the vacuum pump 13 is operated with the first drain valve 1931 and the third drain valve 1933 open. Let Then, the on-off valves 1913 and 1914 are closed, and the on-off valves 1911 and 1912 are opened. As a result, the vacuum chamber 11, the condenser 14, the condenser-side temporary storage tank 151, and the vacuum-chamber-side temporary storage tank 152 are decompressed.

After the atmosphere in the vacuum chamber 11 is sufficiently exhausted and the pressure in the vacuum chamber 11 is reduced, the on-off valves 1911 and 1912 are closed. Subsequently, the steam supply control valve 192 is opened to supply the steam of the cleaning liquid L from the steam generation tank 12 through the steam supply pipe 121 into the vacuum tank 11 . As a result, part of the steam exchanges heat with the workpiece W and liquefies on the surface of the workpiece W, thereby cleaning the surface of the workpiece W (steam cleaning). At that time, the cleaning liquid L that is liquefied from the vapor in the vacuum chamber 11 is recovered in the vacuum chamber side temporary storage tank 152 via the third cleaning liquid recovery pipe 173 .

When the pressure in the vacuum chamber 11 rises to the same level as that in the steam generation chamber 12 (the degree of vacuum decreases), the vapor supply control valve 192 is closed to stop the supply of the vapor of the cleaning liquid L into the vacuum chamber 11. . The timing of stopping the supply of steam is, for example, when the pressure in the vacuum chamber 11 is measured during steam cleaning and the value of the pressure reaches a predetermined value or more. Alternatively, since the time from the start of steam supply until the pressure in the vacuum chamber 11 reaches a predetermined value is generally constant, the time when the predetermined time has passed since the start of steam supply may be the timing for stopping the supply of steam. good. After stopping the supply of steam in this way, the steam in the vacuum chamber 11 is discharged by opening the on-off valves 1911 and 1912 . After closing the on-off valves 1911 and 1912 again, the vapor supply control valve 192 is opened to supply the vapor of the cleaning liquid L into the vacuum chamber 11 . By repeating the supply and discharge of the vapor of the cleaning liquid L into the vacuum chamber 11 a predetermined number of times in this way, the surface of the workpiece W is sufficiently cleaned, and when the workpiece W is sufficiently heated, the vapor cleaning process is performed. ends.

After completion of the steam cleaning, the atmosphere release valve 1941 is opened to bring the inside of the vacuum chamber 11 to atmospheric pressure. Then, the on-off valve 195 is opened while the atmosphere release valve 1941 is left open. As a result, an air flow is formed that reaches the vacuum pump 13 via the vacuum tank 11, the third cleaning liquid recovery pipe 173, the vacuum tank side temporary storage tank exhaust pipe 164, and the pump side connection pipe 1652, and this air flow creates a vacuum. It promotes recovery of the liquid of the cleaning liquid L remaining in the tank 11 to the vacuum tank side temporary storage tank 152 . By recovering the liquid of the cleaning liquid L in the vacuum chamber 11 in this way, it is possible to prevent the liquid of the cleaning liquid L from evaporating and interfering with the decompression at the time of drying under reduced pressure, which will be described below. After the cleaning liquid L is collected, the atmosphere open valve 1941, the third drain valve 1933 and the on-off valve 195 are closed.

(2-2) Drying under reduced pressure Next, the workpiece W is dried under reduced pressure as follows.

First, while the vacuum pump 13 is in operation and the on-off valves 1913 and 1914 are closed, the on-off valves 1911 and 1912 are opened. As a result, the vapor of the cleaning liquid L in the vacuum chamber 11 is exhausted by the vacuum pump 13 through the first exhaust pipe 161 (FIG. 2), and the pressure in the vacuum chamber 11 is rapidly reduced. As a result, bumping occurs from inside the cleaning liquid L adhering to the surface of the work W, and drying is accelerated (bumping drying). Also, in the condenser 14 provided in the first exhaust pipe 161, the vapor of the cleaning liquid L is cooled and condensed. Therefore, the amount of vapor of the cleaning liquid L reaching the vacuum pump 13 can be suppressed. Therefore, it is possible to suppress the deterioration of the ability of the vacuum pump 13, that is, the deterioration of the ability to depressurize the inside of the vacuum chamber 11 due to an increase in the load imposed on the vacuum pump 13 by the cleaning liquid L liquefied in the vacuum pump 13. can prevent the vacuum pump 13 from failing. The cleaning liquid L condensed in the condenser 14 passes through the first cleaning liquid recovery pipe 171 from the bottom of the condenser 14 and is stored in the condenser-side temporary storage tank 151 .

As described above, bumping drying is performed at the stage of condensing the vapor of the cleaning liquid L remaining in the vacuum chamber 11 in the condenser 14, so that the surface of the work W can be dried quickly.

The gas exhausted by the vacuum pump 13 is introduced into the cleaning liquid L stored in the storage tank 15 through the exhaust port 132 and the third exhaust pipe 163 . As a result, the components of the cleaning liquid L in the exhausted gas are absorbed by the cleaning liquid L and recovered. The remaining gas is discharged from a discharge port (not shown) provided in the storage tank 15 .

When the evacuation through the first exhaust pipe 161 is continued for a while, the steam remaining in the vacuum chamber 11 after the completion of the steam cleaning and the gas of the cleaning liquid vaporized from the surface of the work W at the start of the bumping drying are almost exhausted, From the vacuum chamber 11, only the cleaning liquid L remaining on the surface of the workpiece W without being completely vaporized is discharged at the start of the bumping drying. Therefore, by closing the on-off valves 1911 and 1912 and opening the on-off valves 1913 and 1914, the gas in the vacuum chamber 11 (including the gas of the cleaning liquid L vaporized from the surface of the work W) is exhausted by the vacuum pump 13. switch the exhaust route from the first exhaust pipe 161 to the second exhaust pipe 162 (FIG. 3). As a result, the gas in the vacuum chamber 11 is introduced into the vacuum pump 13 through the second exhaust pipe 162 without passing through the condenser 14, so that the cleaning liquid L once liquefied in the condenser 14 can be prevented from being vaporized again. can. Therefore, the pressure reduction in the vacuum chamber 11 can be accelerated, and the drying of the work W can be further accelerated.

When exhausting air through the second exhaust pipe 162 in this manner, the heater 18 heats the gas passing through the second exhaust pipe 162 . As a result, the temperature of the vaporized cleaning liquid L exhausted from the vacuum chamber 11 rises, so that even if the gas is cooled in the vacuum pump 13 , it becomes difficult to liquefy. Therefore, it is possible to further suppress the deterioration of the ability of the vacuum pump 13 to depressurize the inside of the vacuum chamber 11 .

Also at this stage, the gas exhausted by the vacuum pump 13 is introduced into the cleaning liquid L in the storage tank 15, and the components of the cleaning liquid L in the gas are absorbed by the cleaning liquid L and recovered.

At the timing when the work W is sufficiently dried by continuing the exhaust through the second exhaust pipe 162, the on-off valves 1913 and 1914 are closed to end the reduced pressure drying.

After that, by opening the atmosphere release valve 1941, the pressure in the vacuum chamber 11 is brought to the atmospheric pressure. As a result, the lid 111 of the vacuum chamber 11 can be opened to take out the work W that has been steam cleaned and dried under reduced pressure. Further, by opening the atmospheric release valves 1942 and 1943, the pressure in the condenser 14 and the condenser-side temporary storage tank 151 is brought to the atmospheric pressure, and then by opening the second drain valve 1932, the second The cleaning liquid L in the condenser-side temporary storage tank 151 is recovered to the storage tank 15 through the cleaning liquid recovery pipe 172 . Furthermore, after the pressure in the vacuum tank side temporary storage tank 152 is set to the atmospheric pressure by opening the atmosphere release valve 1944, the fourth drain valve 1934 is opened and the liquid transfer pump 1741 is operated to create a vacuum. The cleaning liquid L in the tank-side temporary storage tank 152 is recovered in the storage tank 15 .

In each step of steam cleaning and reduced-pressure drying described so far, the timing to end steam cleaning, the timing to switch the exhaust path from the first exhaust pipe 161 to the second exhaust pipe 162, and the timing to end the reduced-pressure drying are preliminarily. Experiments may be conducted to appropriately determine the values.

The invention is not limited to the above embodiments.

For example, in the above embodiment, four on-off valves 1911 to 1914 were used as switching valves, but instead, as shown in FIG. Three-way valves 1915 and 1916 may be provided at the position where the first exhaust pipe 161 and the second exhaust pipe 162 merge with the pump-side connecting pipe 1652 . In this case, since both the first exhaust pipe 161 and the second exhaust pipe 162 cannot be closed only by the three-way valves 1915 and 1916, an on-off valve 1917 is further provided in the vacuum chamber side connection pipe 1651.

The storage tank 15 may be omitted as shown in FIG. In this case, the second cleaning liquid recovery pipe 172 and the fourth cleaning liquid recovery pipe 174 connected to the storage tank 15, the second drainage valve 1932, the fourth drainage valve 1934 and the liquid feeding pump 1741 provided therewith are also omitted. At the same time, the downstream end of the third exhaust pipe 163 is open to the atmosphere. Also, the heater 18 may be omitted as shown in FIG. These storage tank 15 and heater 18 may be omitted in the configuration using the four on-off valves 1911 to 1914 shown in FIG. Alternatively, one of the storage tank 15 and the heater 18 may be provided in the configuration shown in FIG. 1 and the other may be omitted. Either or both heaters 18 may be provided.

The storage tank 15 can be used not only as a tank for simply storing the cleaning liquid L, but also as a cleaning tank for cleaning the work W by immersing the work W in the stored cleaning liquid L. In this case, after cleaning in the storage tank 15, it is preferable to perform steam cleaning and reduced-pressure drying in the vacuum tank 11 as finishing.

DESCRIPTION OF SYMBOLS 10... Vapor cleaning and decompression drying apparatus 11... Vacuum tank 111... Vacuum tank cover 12... Steam generation tank 121... Steam supply pipe 13... Vacuum pump 131... Intake port 132... Exhaust port 14... Condenser 15... Storage tank 151... Condenser side temporary storage tank 152 Vacuum tank side temporary storage tank 161 First exhaust pipe 162 Second exhaust pipe 163 Third exhaust pipe 164 Vacuum tank side temporary storage tank exhaust pipe 1651 Vacuum tank side connection pipe 1652 Pump-side connection pipe 171 First cleaning liquid recovery pipe 172 Second cleaning liquid recovery pipe 173 Third cleaning liquid recovery pipe 174 Fourth cleaning liquid recovery pipe 1741 Liquid sending pump 18 Heater 191 Switching valves 1911, 1912, 1913 , 1914, 1917... on-off valves 1915, 1916... three-way valve 192... steam supply control valve 1931... first drain valve 1932... second drain valve 1933... third drain valve 1934... fourth drain valve 1941, 1942 , 1943, 1944 ... atmospheric release valve L ... cleaning liquid W ... work

Claims (3)

a) a vacuum chamber in which the workpiece is hermetically contained;
b) a steam supply unit for supplying steam of the cleaning liquid into the vacuum chamber;
c) a vacuum pump whose exhaust port does not have a connection path with the vacuum chamber;
d) a first exhaust pipe connecting the vacuum chamber and the suction port of the vacuum pump;
e) a condenser provided in the middle of the first exhaust pipe;
f) a second exhaust pipe, which is provided separately from the first exhaust pipe and connects the vacuum chamber and the suction port of the vacuum pump;
g) A vapor cleaning/reduced pressure drying apparatus comprising a switching valve for switching an exhaust path between the vacuum tank and the vacuum pump to either the first exhaust pipe or the second exhaust pipe. 2. The steam cleaning and reduced pressure drying apparatus according to claim 1, further comprising a heater for heating the inside of the second exhaust pipe. 3. The steam cleaning and reduced pressure drying apparatus according to claim 1, further comprising a cleaning liquid storage tank connected to the exhaust port.

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