JP2017110866A - Pressure reduction drier machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate or save an energy source newly added for heating an item to be dried and to increase a drying capability.SOLUTION: This invention comprises a reduced pressure exhaust port 111 for exhausting air and vapor from a decompression vessel 11 into which an object 5 to be dried is fed; an exhaust intake port 12 arranged at the decompression vessel 11; a decompression pump 17 including a pump intake port 171 communicated with the reduced pressure port 111 and a pump exhaust port 172 so as to decompress an inside of the decompression vessel 11; an exhaust port 212 for heating the object communicated with the exhaust intake port 12; a heating device 20 comprising an exhaust flow-in port 201 communicated with the pump exhaust port 172 and exhaust changing-over means 21 for changing-over an exhaust port 222 for heating the object with the pump exhaust and the exhaust flow-in port 201 between the communicated state and a shut-off state; an external shut-off valve 25 for allowing or shutting off a communication between the external part connection port 116 arranged at the decompression vessel 11 and the outside air; and a controller 39 for controlling an operation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vacuum dryer used for drying machine parts after cleaning.

  The machine parts after the cutting process are cleaned by a spray cleaning machine, an ultrasonic cleaning machine or other cleaning devices. The cleaning liquid used in the cleaning device remains in the machine parts after cleaning.

  The vacuum dryer puts the drying object such as machine parts in a closed drying container, and lowers the inside of the drying container below the vapor pressure with respect to the temperature of the drying object to remove the cleaning liquid remaining on the drying object. Evaporate. When the cleaning liquid evaporates, the cleaning liquid takes the latent heat of evaporation from the object to be dried. For this reason, the temperature of the object to be dried decreases as the drying proceeds, and the drying rate decreases as the temperature decreases. In order to increase the drying speed of the object to be dried, a method of heating the object to be dried is taken.

  For example, a method using exhaust heat of a decompression pump has been proposed. Outside air is introduced as cooling air to exchange heat with the exhaust heat of the vacuum pump. The heated air heated by the exhaust heat of the decompression pump is jetted to the outer surface of the decompression container to warm the decompression container (Patent Document 1).

Japanese Patent Application Laid-Open No. 2015-078817

  An object of the present invention is to eliminate or save a newly added energy source for heating an object to be dried, and to increase the drying capacity.

In view of the above-described problems, the present invention is a vacuum dryer, which includes a vacuum container into which an object to be dried is charged, and a vacuum exhaust port provided in the vacuum container and exhausting air and steam from the vacuum container ( 111), an exhaust intake port (112) provided in the decompression vessel, a pump intake port communicating with the decompression exhaust port, and a pump exhaust port, and a decompression pump for decompressing the inside of the decompression vessel, and the exhaust An object heating discharge port (212) communicating with the intake port, an exhaust inflow port (201) communicating with the pump exhaust port, and the object heating discharge port and the exhaust inflow port are in communication with each other. A heating device comprising an exhaust switching means (21) for switching to a shut-off state, an external connection port (116) provided in the decompression vessel, a first port communicating with the external connection port, and the decompression And a second port for outside opening of vessel, the external connection port and the outside air and the external shut-off valve that allows or blocks the communication between the (25) includes a controller for controlling the operation, the.
In this section, for convenience of explanation, the constituent elements are appropriately denoted by reference numerals, and the objects are exemplified, but the constituent elements are not limited to the embodiments.

  According to the above configuration, the pressure-reducing pump is configured such that the exhaust gas switching means brings the object heating discharge port and the exhaust inflow port into communication, and the external shutoff valve allows communication between the external connection port and outside air. The exhaust gas is introduced into the decompression container through the exhaust intake port, and the introduced exhaust gas is discharged from the external connection port to the outside of the decompression container through the external shutoff valve.

  Since the exhaust of the decompression pump is hot, the decompression container and the drying object are directly warmed by the exhaust as the high-temperature exhaust passes through the decompression container. Since the decompression container and the object to be dried are warmed by exhaust, drying is accelerated. In addition, the remaining cleaning liquid can be evaporated again by using the amount of heat given by the exhaust gas by closing the decompression container warmed by the passage of the exhaust gas again and reducing the pressure again. Therefore, the dryness of a dry object improves.

  The reduced pressure dryer according to the present invention preferably further includes a nozzle that is disposed in the vacuum container, communicates with the air inlet, and faces the object to be dried.

  According to the said structure, the exhaust_gas | exhaustion of a pressure reduction pump can be ejected from a nozzle and sprayed on a drying target object. When the exhaust of the vacuum pump directly contacts the surface of the object to be dried, the temperature of the object to be dried rises quickly. Since the surface temperature of the drying object rises, when the drying object comes into contact with the atmosphere, even if the cleaning liquid remains on the surface of the drying object, the remaining cleaning liquid evaporates and the drying object is The effect of drying occurs. When the cleaning liquid remaining on the surface of the object to be dried touches the flow of the exhaust gas, the cleaning liquid evaporates.

  The vacuum dryer according to the present invention preferably further includes a container heating pipe that communicates with the pump exhaust port and has an opening facing the outer surface of the vacuum container, and the heating device includes the container heating pipe and A container heating discharge port communicating therewith, wherein the exhaust switching means includes a predetermined one selected by the controller from the object heating discharge port and the container heating discharge port and the exhaust inflow port; Is allowed to communicate, and the communication between the other and the exhaust inflow port is blocked.

  According to the above configuration, when the exhaust from the decompression pump is not introduced into the decompression container, the exhaust from the decompression pump can be blown to the outer periphery of the decompression container. The vacuum vessel can be heated by exhaust. When the decompression container is heated, the object to be dried put into the decompression container is heated by the radiant heat from the inner surface of the decompression container. The drying speed of the drying object is improved by heating the drying object by the exhaust of the vacuum pump.

  The vacuum dryer according to the present invention is preferably such that the heating device has a branch pipe having one end communicating with the exhaust inflow port and the other end having two outflow ports (321, 322), The exhaust gas switching means includes an exhaust intake valve (21) for switching one outlet of the branch pipe and the discharge port for heating the object between a communication state and a cutoff state, and the other outlet of the branch pipe. And a container heating valve (22) for switching the container heating discharge port between a communication state and a shut-off state.

  According to the said structure, the switching timing of the exhaust_gas | exhaustion of a pressure reduction pump can be set flexibly, and it can comprise simply.

  The vacuum dryer according to the present invention is preferably configured such that a predetermined one selected by the controller among the vacuum exhaust port (111) and an outside air intake port (141) opened to the outside is connected to the pump intake port. An intake air switching device (12) that permits communication and blocks communication between the other and the pump intake port is further provided.

  According to the above configuration, the communication state between the decompression container and the pump intake port of the decompression pump is shut off by the intake air switching device, and the decompression pump can suck the outside air. The inside of the decompression pump can be dried because the decompression pump sucks and exhausts outside air. Further, if the decompression pump sucks outside air in a state where the object warming discharge port and the exhaust inflow port are communicated by the exhaust switching means, the decompression pump warms the sucked outside air, and the decompression container Because the air is exhausted, heated air with low humidity can be blown into the decompression vessel.

  In the decompression dryer according to the present invention, preferably, the external shut-off valve (25) is a decompression destruction valve (253) that regulates a flow rate in a direction in which outside air is introduced, and the decompression dryer (112) A heated exhaust port (117) for discharging the exhaust from the decompression pump introduced into the container, an inflow port (52) communicating with the heated exhaust port, and an outflow port (53) opened to the outside of the decompression container And a heating exhaust valve (51).

  According to the above configuration, since the two valves including the external shutoff valve and the warming exhaust valve are provided, the functions performed by the external shutoff valve and the warming exhaust valve can be separated from each other. That is, when breaking the decompression by taking outside air into the decompression vessel, the decompression break valve is made to function to suppress the rapid pressure rise and smoothly perform the decompression. On the other hand, when exhausting from the exhaust intake port is discharged, a sufficient exhaust amount can be secured by causing the warming exhaust valve to function. By adjusting the size and opening of each valve, the outside air intake and exhaust exhaust speed can be optimally designed.

  The vacuum dryer according to the present invention preferably further includes a filter (19) provided between the exhaust intake port and the pump exhaust port.

  According to the said structure, since the exhaust_gas | exhaustion of a decompression pump can be filtered, it can prevent that a decompression container and a drying target object become dirty with the exhaust_gas | exhaustion introduce | transduced in a decompression container.

  The drying method of the present invention includes a step of sealing a decompression container filled with an object to be dried, a step of decompressing the inside of the decompression container with a decompression pump, a step of breaking the sealed state of the decompression container, and the decompression container And the suction port of the decompression pump is shut off, and the decompression pump sucks the outside air from the suction port, and the outside air sucked by the step of sucking the outside air is introduced into the decompression container and the object to be dried And an exhaust intake step for heating the object and simultaneously exhausting from the decompression vessel.

According to the above configuration, the decompression pump sucks outside air in the step of sucking outside air. The exhaust from the vacuum pump is heated by the drive heat of the vacuum pump. Since the decompression pump sucks in the outside air, the humidity is lower than the air in the decompression container, and high-temperature exhaust gas is introduced into the decompression container. Then, exhaust of the decompression pump is introduced into the decompression container by the exhaust intake step, and at the same time, the exhaust introduced into the decompression container is exhausted from the decompression container. Since the exhaust gas in which the outside air is heated passes through the decompression vessel, the object to be dried put in the decompression vessel exchanges heat with the exhaust. Further, evaporation of the cleaning liquid remaining on the dry object is promoted.
By introducing the exhaust of the decompression pump into the decompression vessel, heat exchange between the surface of the object to be dried and the introduced exhaust is promoted, and the temperature of the object to be dried rises quickly.
Further, the cleaning liquid remaining on the drying object 5 is exchanged between the surface of the drying object 5 and the exhaust, and the drying object 5 has an effect of drying.

  The drying method of the present invention preferably further includes a step of sealing the inside of the decompression vessel and a step of decompressing the inside of the decompression vessel after the exhaust intake step.

As a result of the surface temperature of the dry object being lowered due to the removal of latent heat of evaporation, the cleaning liquid may remain on the surface of the dry object.
According to the above configuration, the residual cleaning liquid can be evaporated again using the amount of heat given by the exhaust gas by closing the decompression vessel heated by the passage of the exhaust gas again and reducing the pressure again. For this reason, when performing drying under reduced pressure again, the cleaning liquid remaining on the object to be dried in the previous operation for drying under reduced pressure can be boiled and evaporated using the applied heat, so that the degree of drying of the object to be dried is improved. .

  According to the above-described invention, it is possible to provide a reduced-pressure drier having an increased drying capacity by eliminating or saving a newly added energy source for heating an object to be dried.

The schematic of the vacuum dryer of a 1st embodiment of the present invention is shown. The perspective view inside the pressure reduction container of the vacuum dryer of 1st Embodiment of this invention is shown. The flowchart of the drying method of 1st Embodiment of this invention is shown. The schematic of the vacuum dryer of 2nd Embodiment of this invention is shown. The flowchart of the drying method of 2nd Embodiment of this invention is shown.

(First embodiment)
A vacuum dryer 10 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. The vacuum dryer 10 includes a vacuum container 11 into which the object 5 to be dried is charged, a vacuum pump 17 that decompresses the inside of the vacuum container 11, a heating device 20, and an intake air switching device 12.

  The decompression pump 17 includes a pump intake port 171 and a pump exhaust port 172. The decompression pump 17 also functions as a blower that sends out the sucked air. As the decompression pump 17, for example, a Roots pump, a scroll pump, a vane pump, a diaphragm pump, or a screw pump can be used. When the decompression pump 17 does not require a cold trap, the inside of the decompression vessel 11 may be decompressed by directly sucking air containing steam. The decompression pump 17 uses a motor 173 as a drive source. The exhaust from the decompression pump 17 is compressed by the decompression pump and warmed by the exhaust heat of the motor 173.

  The decompression vessel 11 is provided with a substantially rectangular inlet 113 through which the drying object 5 is carried in and out. A packing 114 is provided around the insertion port 113. A pair of shutter guides 271 are provided on both sides of the insertion port 113. The shutter 27 is supported by a pair of shutter guides 271 and is slidably guided by the shutter guide 271. The cylinder 28 is an air cylinder and drives the shutter 27. The direction switching valve 283 controls the operation of the cylinder 28 by switching the flow path of the compressed air sent from a compressed air source (not shown). A piston rod 281 of the cylinder 28 is connected to the shutter 27. The cylinder of the cylinder 28 is installed outside the decompression vessel 11 via a connection pin 282.

  The shutter 27 opens the input port 113 when the cylinder 28 is contracted and separated from the input port 113. When the cylinder 28 extends, the cylinder 28 moves toward the insertion port 113, and when the cylinder 28 is covered, the cylinder 28 comes into close contact with the packing 114 and seals the insertion port 113.

  The decompression vessel 11 is provided with a decompression exhaust port 111 for exhausting air and steam, an exhaust intake port 112, and an external connection port 116. The decompression exhaust port 111 communicates with the pump intake port 171 through the intake air switching device 12. The exhaust intake port 112 communicates with the pump exhaust port 172 via the heating device 20. The external connection port 116 communicates with the outside of the decompression vessel 11 through the external shut-off valve 25 to introduce atmospheric pressure outside air or exhaust air and steam into the atmosphere.

  A pressure switch 27 is provided at the external connection port 115. Instead of the pressure switch 27, a pressure sensor may be provided.

  The intake air switching device 12 includes a branch pipe 15, a pressure reducing exhaust valve 13, and an outside air intake valve 14. The branch pipe 15 is a T-shaped or Y-shaped pipe that connects the first inlet 151, the second inlet 152, and the intake connection port 123 that is a common outlet. The decompression exhaust valve 13 is a two-way solenoid valve. The inflow port of the decompression exhaust valve 13 is an intake inflow port 131, and the outflow port 132 is connected to the inflow port 151. The outside air intake valve 14 is also a two-way electromagnetic valve. The inflow port of the outside air intake valve 14 is an outside air inlet 141, and the outflow port 142 is connected to the second inflow port 152.

  The intake air switching device 12 includes an intake air inlet 131, an outside air intake port 141, and an intake connection port 123. The intake air switching device 12 allows the predetermined one selected by the controller 39 among the intake air inlet 131 and the outside air inlet port 141 opened to the outside to allow communication with the intake air connection port 123 and intake air with the other. The communication with the connection port 123 is blocked.

  The intake air switching device 12 can use a three-port flow path switching valve or a three-way valve in place of the above configuration.

  The decompression exhaust port 111 and the intake air inlet 131 are connected by a pipe 29. The intake connection port 123 and the pump intake port 171 are connected.

  The heating device 20 includes a branch pipe 32, an exhaust intake valve 21 and a container warming valve 22 that are exhaust switching means 200, an object heating exhaust port 212 that communicates with the exhaust intake 112, and a pump exhaust 172. And an exhaust inflow port 201 communicating with the air.

  The branch pipe 32 is a T-shaped or Y-shaped pipe that connects the exhaust inflow port 201, the first outflow port 321, and the second outflow port 322. The exhaust intake valve 21 is a two-port solenoid valve having an inflow port 211 that communicates with the first outflow port 321 and an outflow port that is a discharge port 212 for heating the object.

The exhaust intake valve 21 switches the first outlet 321 and the discharge port 212 for heating the object between a communication state and a cutoff state. The container warming valve 22 is a two-port solenoid valve having an inflow port that is the second outlet 322 and an outflow port that is the container warming discharge port 222.
The container warming valve 22 switches the pump exhaust port 172 and the opening 23 between a communication state and a cutoff state. The pipe 33 connects the object heating discharge port 212 and the exhaust intake port 112.

  With this configuration, the exhaust gas switching unit 200 allows the predetermined one selected by the controller 39 among the object warming discharge port 212 and the container warming discharge port 222 to communicate with the exhaust inflow port 201, and And the communication with the exhaust inflow port 201 are blocked.

  The heating device 20 can use a three-port flow path switching valve or a three-way valve in place of the above-described configuration.

  The filter 19 is appropriately provided in consideration of the operation state of the decompression pump 17 and the like, but is desirably provided between the exhaust intake port 112 and the pump exhaust port 172. More desirably, the filter 19 is provided between the first outlet 321 and the exhaust intake valve 21. The filter 19 removes foreign matter, steam, oil, etc. contained in the exhaust of the decompression pump 17.

  The filter 30 is appropriately provided in order to remove foreign substances and moisture from the gas sucked by the vacuum pump 17 in consideration of the outside air, the state of the dry object, and the like. The filter 30 is preferably provided between the intake connection port 123 and the pump intake port 171.

  One end of the container warming pipe 34 is connected to the container warming discharge port 222. The other end of the container heating pipe 34 is an opening 23 that faces the outer wall surface of the decompression container 11 with a gap. The container heating pipe 34 may be branched in the middle and provided with a plurality of openings 23. In that case, each opening 23 is provided so as to face the outer wall surface of the decompression vessel 11.

  An air blow pipe 35 is provided in the decompression vessel 11 so as to surround the drying object 5. The air blow pipe 35 is provided with a plurality of nozzles 37 so as to face the drying object 5. Each nozzle 37 is provided with a nozzle 371.

  The external shutoff valve 25 is attached to the external connection port 116 of the decompression vessel 11. The external shutoff valve 25 is a two-port solenoid valve that includes a first port 251 that communicates with the external connection port 116 and a second port 252 that is released to the outside air. A filter 26 is provided at the second port 252.

  The external shutoff valve 25 is opened when the decompression vessel 11 is sealed and in a decompressed state, and acts as a decompression destruction valve that takes outside air into the decompression vessel 11. The external shut-off valve 25 also functions as a warming exhaust valve that exhausts the exhaust of the decompression pump 17 taken from the exhaust intake 112 when the decompression vessel 11 is at normal pressure. The filter 26 plays a role of filtering foreign matter when taking outside air into the decompression vessel 11. Furthermore, when exhausting the vacuum pump 17, it also functions as a silencer.

  The controller 39 receives the output signal of the pressure switch 27 and controls the direction switching valve 283, the external shutoff valve 25, the heating device 20, and the intake air switching device 12.

  FIG. 3 shows an example of the operation procedure of the vacuum dryer 10. First, the controller 39 operates the decompression pump 17 (S1). Preferably, the decompression pump 17 is operated for a while and waits for the decompression pump 17 to warm up. The decompression pump 17 is warmed by the driving heat of the motor 173 as it operates. The exhaust from the decompression pump 17 is heated by the exhaust heat from the decompression pump 17. The controller 39 switches the direction switching valve 283, sends compressed air to the cylinder 28, and closes the shutter 27 (S2).

  The controller 39 decompresses the decompression container 11 (S3). Specifically, the controller 39 closes the external shutoff valve 25, opens the pressure reducing exhaust valve 13, and closes the outside air intake valve 14. Further, the controller 39 closes the exhaust intake valve 21 and opens the container warming valve 22. Then, the decompression pump 17 sucks air and vapor in the decompression container 11 and exhausts them to the opening 23.

  When the pressure in the decompression vessel 11 decreases and falls below a predetermined pressure, the pressure switch 27 transmits a decompression signal to the controller 39 (S4). After receiving the decompression signal, the controller 39 performs decompression drying for a certain time (S5). The time for drying under reduced pressure is appropriately determined depending on the amount of the cleaning liquid adhering, the volume of the object to be dried 5, the temperature before charging, and the like.

  When the pressure in the decompression vessel 11 is lower than the vapor pressure with respect to the surface temperature of the drying object 5, the cleaning liquid adhering to the drying object 5 boils. Then, the drying object 5 starts to dry. When the cleaning liquid adhering to the drying object 5 boils and evaporates, the cleaning liquid takes the latent heat of evaporation from the drying object 5. Due to boiling and evaporation of the cleaning liquid, the surface temperature of the drying object 5 decreases. When the surface temperature decreases, the amount of heat transfer from the surface to the cleaning liquid decreases. Moreover, the vapor pressure with respect to the surface temperature decreases. For this reason, a drying rate falls with progress of drying.

  The exhaust from the decompression pump 17 is ejected from the opening 23 and blown to the outer surface of the decompression container 11. The exhaust from the decompression pump 17 is warmed by the driving heat of the decompression pump 17. The outer surface of the decompression vessel 11 is heated by exhaust. The exhaust heat of the decompression pump 17 is transmitted from the outer surface to the inner surface of the decompression vessel 11, is radiated from the inner surface of the decompression vessel 11, and is transmitted to the drying object 5. That is, the drying object 5 is heated by the exhaust heat of the decompression pump 17. Since the drying object 5 is heated by the radiant heat from the decompression vessel 11, the drying speed of the drying object 5 is improved.

  The controller 39 opens the external shutoff valve 25 (S6). Outside air passes through the filter 26 and the external shutoff valve 35 and flows into the decompression vessel 11. The pressure in the decompression vessel 11 gradually increases and reaches atmospheric pressure.

  Preferably, the controller 39 operates the intake air switching device 12 to switch the intake air of the decompression pump 17 to the outside air (S7). Specifically, the outside air intake valve 14 is opened, and the pressure reducing exhaust valve 13 is closed. The decompression pump 17 takes in outside air from the outside air inlet 141 and exhausts it to the opening 23. The inside of the decompression pump 17 is dried by ventilating the inside of the decompression pump 17 to the outside air. Further, the exhaust of the decompression pump 17 is also dried together with the drying in the decompression pump 17.

  The controller 39 opens the exhaust intake valve 21 (S8). Further, the controller 39 closes the container heating valve 22 (S9). Exhaust gas discharged from the decompression pump 17 is taken into the decompression vessel 11 from the exhaust intake port 112, warms the drying object 5, and is discharged from the external connection port 116. At this time, since the air blow pipe 35 and the injection hole 371 are provided in the exhaust intake port 112, the exhaust gas is blown directly onto the drying object 5 through the injection hole 371.

  The controller 39 maintains this state for a certain time (S10). Since the exhaust of the decompression pump 17 is warmed by the driving heat of the decompression pump 17, the temperature is high and the relative humidity is low. The drying object 5 is warmed by blowing exhaust. Further, since the cleaning liquid remaining on the drying object 5 is exchanged between the exhaust and the drying object 5, an effect of further drying the drying object 5 is produced. The heating time of the drying object 5 in step S10 is appropriately determined according to the state after the reduced pressure drying operation of the drying object 5 and the temperature rise of the drying object 5.

  The controller 39 opens the container warming valve 22 (S11). The exhaust intake valve is closed (S12). The decompression of the decompression vessel 11 is started (S13). Steps S13 to S17 are the same as steps S3 to S7 described above, and a description thereof will be omitted.

  In step 3 to step 5, the cleaning liquid may remain on the surface of the drying object 5 as a result of the surface temperature of the drying object 5 being lowered due to the removal of latent heat of evaporation. By blowing the exhaust of the decompression pump 17 onto the drying object 5, heat exchange between the surface of the drying object 5 and the introduced exhaust is promoted, and the temperature of the drying object 5 quickly increases. For this reason, when the reduced-pressure drying is performed again in step 13 to step S17, the cleaning liquid remaining on the drying object 5 in the previous reduced-pressure drying operation can boil and evaporate using the applied heat.

  The controller 39 opens the shutter 27 (S18).

(Second Embodiment)
The vacuum dryer 50 according to the second embodiment will be described with reference to FIG. The vacuum dryer 50 of the present embodiment is greatly different in that the external shut-off valve 253 is a vacuum breaker valve and does not assume exhaust from the decompression vessel 11, and the heating exhaust valve 51 is provided. Hereinafter, the difference between the vacuum dryer 50 and the vacuum dryer 10 of the first embodiment will be mainly described. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The external shut-off valve 253 is a two-port solenoid valve including an inflow port 255 that opens to the outside and an outflow port 254 that communicates with the external connection port 116. A filter 55 is provided at the inflow port 255.

  The decompression vessel 11 further includes a heated exhaust port 117. A heating exhaust valve 51 is provided at the heating exhaust port 117. The warming exhaust valve 51 is a two-port solenoid valve that includes an outflow port 53 that is open to the atmosphere and an inflow port 52 that communicates with the warming exhaust port 117. The warming exhaust port 117 and the warming exhaust valve 51 have a larger diameter than the external connection port 116 and the external shutoff valve 253.

  The external shutoff valve 253 and the warming exhaust valve 51 are controlled by the controller 39.

  The decompression break valve 253 that is an external shut-off valve is a so-called vacuum break valve that regulates the flow rate in the direction in which outside air is introduced, and is used for opening the decompression container 11 to the atmosphere. The opening of the depressurization destruction valve 253 limits the pressure increase rate when the depressurization container 11 leaves the depressurized state. The decompression destruction valve 253 suppresses a rapid increase in the pressure in the decompression vessel 11, thereby preventing the outside air from suddenly flowing into the decompression vessel 11 and damaging the drying target. The decompression / breakdown valve 253 should not have an effective area that is too wide.

  On the other hand, the warming exhaust valve 51 is used only for the purpose of exhausting the exhaust taken in from the exhaust intake 112. Since the exhaust pressure of the decompression pump 17 is very low, if the effective sectional area of the warming exhaust valve 51 is narrow, the flow rate may decrease due to pressure loss.

  In other words, depending on the exhaust characteristics of the exhaust pump 17 and the volume of the decompression vessel 11, an appropriate effective cross-sectional area may differ between exhaust discharge and decompression failure. According to the vacuum dryer 50 of the present embodiment, since the warming exhaust valve 51 and the vacuum breaker valve 253 are provided separately, each valve can be designed with an appropriate opening degree.

  FIG. 5 shows an example of the operation procedure of the vacuum dryer 50. Steps S1 to S6 are the same as in the first embodiment. When the decompression destruction valve 253 which is an external shut-off valve is opened (S6), outside air flows into the decompression vessel 11. When the pressure in the decompression vessel 11 rises to near atmospheric pressure, the pressure switch 27 transmits a pressure arrival signal to the controller 39 (S51). In response to the pressure arrival signal, the controller 39 closes the external shutoff valve 253 (S52). The controller 39 continues to open the warming exhaust valve 51 (S53), and thereafter executes steps S7 to S18 as in the first embodiment.

  Note that the order of step S52 and step S53 may be interchanged, or may be performed simultaneously.

  Further, the timing for closing the external shut-off valve 253 can be changed after a certain period of time has elapsed after the external shut-off valve 253 is opened, instead of being conditional on reaching the pressure in the decompression vessel 11 (S51). At this time, the degree of pressure increase is confirmed in advance, and the time until the pressure in the decompression vessel 11 becomes close to atmospheric pressure can be used as the predetermined time.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to above-described embodiment, It can change and implement suitably.

DESCRIPTION OF SYMBOLS 10, 50 Vacuum dryer 11 Depressurization container 111 Depressurization exhaust port 112 Exhaust intake port 116 External connection port 117 Heating exhaust port 12 Intake switching device 13 Depressurization exhaust valve 14 Outside air suction valve 141 Outside air suction port 17 Decompression pump 19 Filter 20 Warming Device 200 Exhaust gas switching means 201 Exhaust gas inflow port 21 Exhaust intake valve (exhaust gas switching means)
212 Exhaust port for object heating 22 Container heating valve (exhaust switching means)
222 Container heating discharge port 23 Opening 25, 253 External shut-off valve 251 First port 252 Second port 321 First outlet 322 Second outlet 37 Injection hole 39 Controller 5 Drying object 51 Heating exhaust valve 52 Inflow port 53 Outflow port

Claims (9)

A vacuum dryer,
A decompression container into which an object to be dried is charged;
A vacuum exhaust port provided in the vacuum container and exhausting air and steam from the vacuum container;
An exhaust inlet provided in the decompression vessel;
A pump suction port communicating with the decompression exhaust port, and a pump exhaust port, and a decompression pump for decompressing the interior of the decompression vessel;
The object heating discharge port communicating with the exhaust intake port, the exhaust inflow port communicating with the pump exhaust port, the object heating discharge port, and the exhaust inflow port in a communication state and a cutoff state. An exhaust gas switching means for switching, and a heating device comprising:
An external connection port provided in the decompression vessel;
An external shut-off valve comprising a first port communicating with the external connection port and a second port opening to the outside of the decompression vessel, and allowing or blocking communication between the external connection port and outside air;
A vacuum dryer comprising: a controller for controlling operation;   2. The vacuum dryer according to claim 1, further comprising a nozzle that is disposed in the vacuum container, communicates with the exhaust intake port, and faces the object to be dried. The vacuum dryer according to claim 1 or 2,
A container heating pipe that communicates with the pump exhaust port and includes an opening facing the outer surface of the decompression container;
The heating device has a container heating discharge port communicating with the container heating pipe,
The exhaust gas switching means allows communication between a predetermined one selected by the controller from the object warming discharge port and the container warming discharge port and the exhaust inflow port, and the other and the exhaust inflow port. A vacuum dryer that cuts off communication with the port. A vacuum dryer according to claim 3,
The heating device is
A branch pipe having one end communicating with the exhaust inflow port and the other end having two outlets;
The exhaust gas switching means is
An exhaust intake valve that switches between one outlet of the branch pipe and the discharge port for heating the object between a communication state and a cutoff state;
A vacuum dryer comprising: a container heating valve that switches the other outlet of the branch pipe and the container heating discharge port between a communication state and a shut-off state. The vacuum dryer according to any one of claims 1 to 4,
Among the decompression exhaust port and the outside air intake port opened to the outside, intake air that allows communication between the predetermined one selected by the controller and the pump intake port and blocks communication between the other and the pump intake port A vacuum dryer further comprising a switching device. A vacuum dryer according to any one of claims 1 to 5,
The external shut-off valve is a decompression destruction valve that regulates the flow rate in the direction of introducing outside air,
A heating exhaust port for discharging exhaust from the decompression pump introduced into the decompression vessel from the exhaust intake port, an inflow port communicating with the heating exhaust port, and an outflow port released to the outside of the decompression vessel A vacuum dryer further comprising a heated exhaust valve. The vacuum dryer according to any one of claims 1 to 6,
A filter provided between the exhaust intake port and the pump exhaust port;
A vacuum dryer further provided. A method for drying an object to be dried,
Sealing the vacuum container filled with the dry object;
Depressurizing the interior of the decompression vessel with a decompression pump;
Breaking the sealed state of the vacuum vessel;
Shutting off the communication state between the decompression container and the suction port of the decompression pump, and the decompression pump sucks outside air from the suction port;
Exhaust air intake step of introducing the outside air sucked in the step of sucking the outside air into the decompression container to heat the drying object and simultaneously exhausting from the decompression container;
A method for drying an object to be dried. 9. The drying method according to claim 8, further comprising after the exhaust intake step.
Sealing the inside of the vacuum vessel;
Reducing the pressure in the vacuum container;
A method for drying an object to be dried.

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