JP5782368B2 - Vacuum drying equipment - Google Patents

Description

  The present invention relates to a vacuum drying apparatus, and more particularly, to a vacuum drying apparatus that evaporates moisture from an object to be dried such as salt water such as muddy water or seawater to dry the object to be dried.

  It is known that when a waste is discarded, the disposal of the waste is facilitated by evaporating moisture in the waste and drying the waste. Examples of such waste include organic waste and sludge, and further muddy water generated in tunnels and the like. Furthermore, when desalinating seawater, there is a case where concentrated water generated by leachate or membrane treatment is dried.

  2. Description of the Related Art Conventionally, a drying device using a vacuum tank is known as a vacuum drying device for drying seawater, concentrated water, and further an object to be dried such as muddy water (for example, see Patent Document 1). This drying apparatus includes a vacuum tank for storing waste and a water vapor compressor for compressing water vapor from the vacuum tank. It also has a water vapor condenser that is thermally coupled to the vacuum tank, and a non-condensable gas discharge means that spontaneously discharges the non-condensable gas from the water vapor condenser and the condensed water from the water vapor condenser spontaneously. Condensate drainage means for draining is provided.

  When water vapor is condensed by the water vapor condenser, condensation heat is generated. Here, in the vacuum drying apparatus disclosed in Patent Document 1, a water vapor condenser is provided in the vacuum tank. For this reason, the inside of a vacuum tank can be heated with the condensation heat which generate | occur | produces when water vapor condenses, and it contributes to the drying of the waste in a vacuum tank.

  Further, in this type of vacuum drying apparatus, there is a sludge drying apparatus that recovers heat obtained by condensing moisture contained in sludge by a heat pump and uses it as a heat source when drying sludge (see, for example, Patent Document 2). ). This sludge drying apparatus includes a vacuum dryer and an ejector, and the inside of the vacuum dryer is decompressed by the ejector. A condenser is disposed between the vacuum dryer and the ejector to condense the exhaust of the vacuum dryer. Further, cooling water is circulated and supplied to the condenser from the heat pump, and heat exchange is performed between the exhaust gas and the cooling water. Moreover, a heat pump supplies heat pump vapor | steam with respect to a vacuum dryer, and dries the sludge in a vacuum dryer. Further, the cooling water takes heat from the exhaust and the condenser and becomes cooling drainage, and the heat pump steam is liquefied by applying heat to the sludge and becomes a heating medium. The heat pump exchanges heat between the cooling wastewater and the heating medium, uses the cooling wastewater as cooling water, and uses the heating medium as heat pump steam. Thus, energy consumption for drying the sludge is reduced.

JP-A-9-126652 JP 2010-158616 A

  However, the drying apparatus disclosed in Patent Document 1 uses a compressor that compresses water vapor in the vacuum tank. For this reason, there existed a problem that the whole apparatus became large-scale. It is conceivable that the water vapor in the vacuum tank is sucked using, for example, a vacuum pump having a simpler device configuration than the compressor.

  However, when the water vapor in the vacuum tank is sucked using the vacuum pump, the water vapor is condensed on the upstream side of the vacuum pump. For this reason, there has been a problem that it becomes difficult to use the heat of condensation when the water vapor is condensed to dry the waste (the material to be dried) in the vacuum tank (drying tank).

  Moreover, in the sludge drying apparatus disclosed by the said patent document 2, when condensing the gas obtained by drying sludge, a capacitor | condenser (condenser) is used. For this reason, since it is necessary to use a heat pump as a cooling device (cooling tower) for cooling a condenser, a plurality of heat pumps are used. Therefore, there has been a problem that the entire apparatus becomes large. Moreover, heat pump steam is supplied from the heat pump to the vacuum dryer. Here, although the inside of the vacuum dryer is depressurized, the inside of the heat pump is not depressurized, so the heat pump steam needs to be 100 ° C. or higher. For this reason, the heat pump steam may have to be heated, and there is a problem that much heat energy is consumed.

  Accordingly, an object of the present invention is to provide a vacuum drying apparatus that has a simple configuration and can reduce the consumption of heat energy.

  A vacuum drying apparatus according to the present invention that has solved the above-described problems includes a drying tank that stores a material to be dried, evaporates moisture in the stored material to be dried, a vacuum pump that decompresses the inside of the drying tank, and a drying tank. A heat pump that absorbs the heat of condensation due to condensation of the steam discharged from the drying tank when the inside is depressurized and supplies the heat to the drying tank. The heat pump absorbs the heat of condensation via the condensation side heat medium and evaporates. The condensation heat is supplied to the drying tank through the side heat medium.

  In the vacuum drying apparatus according to the present invention, a vacuum pump is used to depressurize the drying tank. For this reason, it can be set as a simple structure, without requiring large facilities, such as a water vapor compressor. Further, since the inside of the drying tank is evacuated by a vacuum pump, the moisture contained in the material to be dried evaporates at a temperature of 100 ° C. or less. Here, when heat pump steam is used as the evaporation side heat medium, since the heat pump steam is 100 ° C. or higher, excess heat is applied to evaporate the moisture contained in the object to be dried. . In this regard, in the vacuum drying apparatus according to the present invention, the heat pump absorbs the condensation heat via the condensation side heat medium, and supplies the condensation heat to the drying tank via the evaporation side liquid heat medium. For this reason, condensation heat can be supplied to the drying tank at a temperature of less than 100 ° C. Therefore, consumption of heat energy can be reduced.

  Here, the vacuum pump is an oil-type vacuum pump, and an oil-water separator is connected to the oil-type vacuum pump. The cold pump that condenses the vapor discharged from the drying tank between the vacuum pump and the drying tank. A trap is provided, and the heat pump can absorb the heat of condensation of the vapor condensed in the cold trap.

  In this way, when the vacuum pump is an oil type vacuum pump, a cold trap is disposed between the vacuum pump and the drying tank, and the vapor is mixed with the oil in the vacuum pump by condensing the vapor with the cold trap. Can be prevented. Here, by absorbing the condensation heat of the steam condensed in the cold trap, the heat of condensation can be absorbed efficiently.

  In addition, the cold trap and the vacuum pump are connected by a pipe so that steam discharged from the cold trap can flow through the pipe, and the pressure adjusting valve can be provided in the pipe.

  In this way, the pressure adjustment valve is provided in the piping, so that the pressure relationship in the drying tank and the cold trap is adjusted, and the pressure is suitable for promoting evaporation in the drying tank and promoting condensation in the cold trap. While reducing the pressure in the drying tank, it is possible to condense the vapor.

  Furthermore, the vacuum pump is a water-sealed vacuum pump, and the heat pump absorbs heat of condensation caused by condensation of steam discharged from the drying tank by the water-sealed vacuum pump from the water-sealed vacuum pump. it can.

  Thus, when using a water ring vacuum pump as a vacuum pump, vapor | steam is conveyed to a water ring vacuum pump and condenses within a water ring vacuum pump. For this reason, the heat of condensation of the steam can be suitably absorbed by absorbing the heat of condensation due to the condensation of the steam from the water-sealed vacuum pump.

  The heat pump can include a heat exchanger that exchanges heat with the outside air.

  In this way, the heat pump includes a heat exchanger that exchanges heat with the outside air, and additionally performs heat exchange with the outside air when the heat balance between the vacuum pump and the drying tank is poor. The heat balance can be adjusted.

  According to the vacuum drying apparatus according to the present invention, it is possible to use the heat of condensation of water vapor to dry the dried product while having a simple configuration.

It is a block diagram of the vacuum dryer which concerns on 1st Embodiment. It is a block diagram of the vacuum dryer which concerns on 2nd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each embodiment, portions having the same function are denoted by the same reference numerals, and redundant description may be omitted.

  FIG. 1 is a configuration diagram of a vacuum drying apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the vacuum drying apparatus M1 according to the first embodiment includes a drying tank 1, an oil-type vacuum pump 2, and a cold trap 3 that store and dry an object to be dried. Further, the vacuum drying apparatus M1 includes an upstream-side circulation pipe 4 and a downstream-side circulation pipe 5, and further includes a heat pump 6. The drying tank 1 and the cold trap 3 are connected by an upstream-side flow pipe 4 through which a gas (steam) such as water vapor can flow, and the cold trap 3 and the oil-type vacuum pump 2 also flow water vapor. They are connected by a downstream flow pipe 5 that is made possible.

  The drying tank 1 includes a drying chamber 11, and a heating jacket 12 is disposed around the drying chamber 11. In the drying chamber 11, salt water such as sludge and seawater is accommodated as an object to be dried D. The drying chamber 11 is connected to the distal end side of the upstream circulation pipe 4, and the drying chamber 11 communicates with the upstream circulation pipe 4. The heating jacket 12 is configured to allow the evaporation side heat medium circulated and supplied from the heat pump 6 to flow. As the evaporation side heat medium, a liquid heat medium (for example, water) or refrigerant vapor is used. Further, a discharge port 13 for discharging the dried material D to be dried is formed in the lower portion of the drying chamber 11.

  The drying tank 1 may be a jacket type having a heating jacket 12 or a plate type having a heating plate. Further, fins can be formed in the drying chamber 11 to enhance heat transfer. In this case, it is preferable that the fin is long at the top, short at the bottom, and the size of the fin opening is not smaller than the heat transfer surface. In addition, a heat transfer process can be performed on the drying chamber 11.

  The drying tank 1 is connected to a cold trap 3 and an oil type vacuum pump 2. Among these, a downstream flow pipe 5 is piped between the oil type vacuum pump 2 and the cold trap 3, and an upstream flow pipe 4 is piped between the cold trap 3 and the drying tank 1. .

  The oil type vacuum pump 2 includes a pump body 21 and an oil / water separator 22. The pump main body 21 exhibits a suction force for sucking gas by circulating oil. The pump body 21 is connected to the rear end side of the downstream flow pipe 5, and the pump body 21 communicates with the downstream flow pipe 5. The suction force of the pump main body 21 acts on the drying chamber 11 of the drying tank 1 through the flow pipes 4 and 5 and the cold trap 3 to reduce the pressure in the drying chamber 11 and form a vacuum state in the drying chamber 11. .

  The oil / water separator 22 is connected to the pump main body 21 and separates and removes water mixed in the pump main body 21 from the oil in the pump main body 21. Thus, the oil / water separator 22 performs the water draining operation in the pump body 21. Moreover, the pump body 21 discharges the sucked gas such as water vapor to the outside.

  The cold trap 3 includes a condensing heat exchanger, and the condensing heat exchanger includes a condensing heat exchanger 31 through which water vapor sucked by the oil vacuum pump 2 passes. The condensation heat exchanger 31 in the condensation heat exchanger is connected to the rear end of the upstream flow pipe 4 and the tip of the downstream flow pipe 5, and the condensation heat exchanger 31 is cooled. It has a hot surface. Further, the cold trap 3 includes a water tank 32. The water tank 32 is provided when the refrigerant is a liquid refrigerant.

  The condensing heat exchanger 31 in the condensing heat exchanger is submerged in the condensing side heat medium stored in the water tank 32, and the heat transfer surface of the condensing heat exchanger 31 is in contact with the condensing side catalyst. . As the condensation side heat medium, a liquid heat medium such as water is used. The heat transfer surface of the condensing heat exchanger 31 is cooled and the heat transfer surface is kept in a cold state because the condensation side heat medium stored in the water tank 32 is in contact with the heat transfer surface.

  The heat pump 6 is a so-called cold temperature simultaneous extraction heat pump that simultaneously extracts cold and warm heat. One end side of the evaporation side high temperature pipe 6 </ b> A and the evaporation side low temperature pipe 6 </ b> B is connected to the heat pump 6. The heat pump 6 is connected to one end side of a condensing side low temperature pipe 6C and a condensing side high temperature pipe 6D.

  The other end of the evaporation side high temperature pipe 6A is connected to the heating jacket 12 in the drying tank 1, and the heat pump 6 supplies a high temperature evaporation side heat medium to the heating jacket 12 via the evaporation side high temperature pipe 6A. doing. The other end side of the evaporation side low temperature pipe 6B is connected to the heating jacket 12 in the drying tank 1, and the heat pump 6 absorbs the heat of evaporation from the material D to be dried via the evaporation side low temperature pipe 6B. The evaporation side heat medium that has become low in temperature is received from the heating jacket 12.

  Furthermore, the other end side of the condensation side low temperature pipe 6C is connected to the water tank 32 in the cold trap 3, and the heat pump 6 supplies a low temperature condensation side heat medium to the water tank 32 via the condensation side low temperature pipe 6C. Yes. And the other end side of condensation side high temperature piping 6D is connected to the water tank 32 in the cold trap 3, and the heat pump 6 absorbs the condensation heat when water vapor condenses through the condensation side high temperature piping 6D. The condensation side heat medium that has reached a high temperature is received from the water tank 32.

  Further, the heat pump 6 circulates and supplies the evaporation side heat medium to the piping in the heating jacket 12 through the evaporation side high temperature piping 6A and the evaporation side low temperature piping 6B. The evaporation side heat medium is cooled by the object to be dried D accommodated in the drying chamber 11 absorbing the heat of evaporation. On the other hand, the heat pump 6 circulates and supplies the condensation side heat medium to the water tank 32 in the cold trap 3 via the condensation side low temperature pipe 6C and the condensation side high temperature pipe 6D. The condensation side heat medium is heated by absorbing the heat of condensation when water vapor is condensed.

  Furthermore, the heat pump 6 includes a heat exchanger (not shown). This heat exchanger performs heat exchange between the evaporation side heat medium or the condensation side heat medium and the outside air. By operating the heat exchanger, heat can be absorbed from the outside air to the evaporation side heat medium, and heat can be given to the outside air from the evaporation side heat medium. The heat exchanger can also exchange heat between the condensation side heat medium and the outside air.

  The upstream flow pipe 4 is provided with an on-off valve 7, and the downstream flow pipe 5 is provided with a pressure regulating valve 8 and a release valve 9. By opening the on-off valve 7, the pressure regulating valve 8, and the release valve 9, the upstream flow pipe 4 and the downstream flow pipe 5 become atmospheric pressure. Further, by closing the release valve 9 and adjusting the opening degree of the pressure regulating valve 8, it is possible to adjust the pressure in the upstream flow pipe 4 and the downstream flow pipe 5.

  Next, a procedure for drying an object to be dried by the vacuum drying apparatus M1 according to this embodiment will be described. The vacuum drying apparatus M1 according to the present embodiment is a so-called batch-type vacuum drying apparatus, and after the dried material stored in the drying chamber 11 is dried, a new material to be dried is dried. When the dried product is dried by the vacuum drying apparatus M <b> 1, first, the discharge port 13 in the drying tank 1 is closed and the material to be dried D is put into the drying chamber 11. In addition, the on-off valve 7 provided in the upstream-side flow pipe 4 is in a closed state, and the drying chamber 11 is sealed to make the drying chamber 11 airtight.

  On the other hand, the heat pump 6 is operated, the evaporation side heat medium is circulated and supplied to the evaporation side pipes 6A and 6B, for example, as hot water, and the condensation side heat medium is circulated and supplied to the condensation side pipes 6C and 6D, for example, as cold water. At this time, the temperature of the evaporation side heat medium that is circulated and supplied to the evaporation side pipes 6A and 6B is adjusted to 30 ° C. to 70 ° C., and the temperature of the condensation side heat medium that is circulated and supplied to the condensation side pipes 6C and 6D Adjust to ° C.

  When the temperature of the evaporation side heat medium and the condensation side heat medium is adjusted and the temperature is stabilized, the on-off valve 7 is released, and a ventilation state is formed between the drying chamber 11 and the upstream flow pipe 4. At the same time, the oil-type vacuum pump 2 is operated to discharge the air in the drying chamber 11 and depressurize the drying chamber 11. By depressurizing the inside of the drying chamber 11, the inside of the drying chamber 11 becomes a vacuum state.

  In the drying tank 1 in which the pressure in the drying chamber 11 is reduced, heat exchange is performed between the material to be dried D accommodated in the drying chamber 11 and the evaporation side heat medium supplied to the heating jacket 12. By this heat exchange, the evaporation side heat medium absorbs the heat of evaporation by the object to be dried D, the water contained in the object to be dried D evaporates, and the object to be dried D is dried.

  The evaporated water passes through the upstream flow pipe 4 and moves to the heat exchanger 31 for condensation in the cold trap 3. In the heat exchanger 31 for condensation in the cold trap 3, heat exchange is performed with, for example, cold water supplied from the heat pump 6 via the condensation side low temperature pipe 6C. In this heat exchange, for example, cold water obtains heat of condensation of water vapor, and in the heat exchanger 31 for condensation, the water vapor is condensed into water. However, a part of the water vapor that has not been condensed passes through the downstream flow pipe 5 as it is and moves to the oil-type vacuum pump 2.

  At this time, the opening degree of the pressure regulating valve 8 is adjusted, and the water vapor pressure of the condensation heat exchanger 31 provided in the drying chamber 11 and the cold trap 3 in the drying tank 1 is adjusted. The water vapor pressure corresponding to the drying chamber temperature Te, which is the temperature, and the water vapor pressure corresponding to the cold trap temperature Tc, which is the temperature in the condensing heat exchanger 31, are set to an intermediate value. Here, the drying chamber temperature Te is higher than the cold trap temperature Tc. By adjusting the water vapor pressure in this way, water vapor can be effectively condensed. In this way, the drying process of the to-be-dried object D is performed.

  Furthermore, heat exchange is performed between the evaporation side heat medium and the condensation side heat medium and the outside air by a heat exchanger provided in the heat pump 6, and heating and heat removal for the evaporation side heat medium and the condensation side heat medium are performed. It can also be balanced. By balancing heating and heat removal in this way, heat exchange between evaporation and condensation of moisture contained in the object to be dried can be performed more efficiently.

  Further, in the vacuum drying apparatus M1 according to the present embodiment, the oil-type vacuum pump 2 is used when the inside of the drying chamber 11 is decompressed. For this reason, it is not necessary to use large equipment such as a compressor. Therefore, it can be set as a simple structure. Further, by using the oil type vacuum pump 2 as a vacuum pump, the cold trap 3 is disposed between the oil type vacuum pump 2 and the drying tank 1. By condensing water vapor with the cold trap 3, it is possible to prevent the water vapor from being mixed with oil in the oil type vacuum pump 2.

  Furthermore, the oil-type vacuum pump 2 is provided with an oil / water separator 22. For this reason, even when water vapor or water condensed with water vapor moves to the oil-type vacuum pump 2, the oil and water can be easily separated. Therefore, the oil type vacuum pump 2 can be operated reliably.

  Moreover, in order to evaporate the moisture contained in the material to be dried D and dry the material to be dried D, it is necessary to apply heat to the material to be dried D. While the drying object D is being dried, the inside of the drying chamber 11 is in a vacuum state, so that forced convection or boiling heat transfer with high heat transfer efficiency can be generated at a low temperature.

  For this reason, the evaporation side heat medium supplied to the heating jacket 12 is, for example, a liquid, and even if the temperature is a low temperature of 100 ° C. or less, heat can be applied to the material D to be dried. The water in D can be evaporated. Therefore, consumption of heat energy can be reduced.

  Further, water vapor generated by evaporation of the moisture of the material D to be dried in the drying chamber 11 is sucked by the oil-type vacuum pump 2 and moves to the condensing heat exchanger 31 of the condensing heat exchanger in the cold trap 3. . A water tank 32 is provided around the condensation heat exchanger 31, and a low-temperature condensation-side heat medium is supplied to the water tank 32.

  In the cold trap 3, heat exchange is performed between the water vapor passing through the heat exchanger 31 for condensation and the condensation side heat medium stored in the water tank 32, and the condensation side heat medium absorbs the heat of condensation from the water vapor. Condenses. On the other hand, the condensation heat medium is heated by the movement of the condensation heat when the water vapor condenses. The heated condensation side heat medium flows into the heat pump 6.

  Here, the heat pump 6 circulates and supplies the evaporation side heat medium to the drying tank 1 and circulates and supplies the condensation side heat medium to the cold trap 3. The evaporation side heat medium returning from the drying tank 1 to the heat pump 6 absorbs the heat of evaporation by the moisture contained in the material D to be dried, while the condensation side heat medium returning from the cold trap 3 absorbs the heat of condensation from the water vapor. ing. The evaporation heat Qe absorbed by the evaporation side heat medium and the condensation heat Qc absorbed by the condensation side heat medium have a relationship in which the absolute values are substantially equal and the signs are reversed if there is no heat loss. For this reason, by performing heat exchange between the evaporation side heat medium and the condensation side heat medium by the heat pump 6, evaporation at the time of evaporating the moisture contained in the material to be dried D from the condensation heat Qc when the water vapor condenses. It can be used as heat Qe.

  Further, immediately after the start of the drying process, the condensation heat Qc cannot be obtained, so the condensation heat Qc cannot be used as the evaporation heat Qe for evaporating the moisture contained in the material D to be dried. Therefore, by using a heat exchanger provided in the heat pump 6, the outside air heat Qa that is the heat of the outside air can be absorbed and used as the evaporation heat Qe. Thereafter, when the operation of the drying process is stabilized, the condensation heat Qc can be used as the evaporation heat Qe, and the operation with high thermal efficiency can be performed. Even if it is not immediately after starting the drying process, if the condensation heat Qc is insufficient with respect to the required evaporation heat Qe, the outside heat Qa can be taken in and used as the evaporation heat Qc. .

  Furthermore, when a condenser is used to condense water vapor, it is necessary to provide a heat pump as a cooling device for cooling the condenser. In this regard, the vacuum drying apparatus M1 uses the cold trap 3 for condensing water vapor. Since there is little demand for cooling the cold trap 3, it is not necessary to provide a heat pump as a separate cooling device, and the device can be simplified correspondingly.

  Next, a second embodiment of the present invention will be described. FIG. 2 is a configuration diagram of a vacuum drying apparatus according to the second embodiment. As shown in FIG. 2, the vacuum drying apparatus M2 according to the second embodiment is different in vacuum pump from the vacuum drying apparatus M1 according to the first embodiment. In the vacuum drying apparatus M1 in the first embodiment, the oil type vacuum pump 2 is used as a vacuum pump. On the other hand, in the vacuum drying apparatus M2 according to the present embodiment, the water ring vacuum pump 50 is used as the vacuum pump.

  The water-sealed vacuum pump 50 and the drying tank 1 are connected by a flow pipe 51 through which a gas such as water vapor can flow. The front end side of the circulation pipe 51 communicates with the drying chamber 11 in the drying tank 1, and the rear end portion of the circulation pipe 51 communicates with the water ring vacuum pump 50. The suction force of the water-sealed vacuum pump 50 acts on the drying chamber 11 of the drying tank 1 through the flow pipe 51 to reduce the pressure in the drying chamber 11 and form a vacuum state in the drying chamber 11.

  Further, the vacuum drying device M2 includes a heat pump 6. One end side of the condensation side low temperature pipe 6C and the condensation side high temperature pipe 6D is connected to the heat pump 6, and the other end side of the condensation side low temperature pipe 6C and the condensation side high temperature pipe 6D is connected to the water-sealed vacuum pump 50. ing. The heat pump 6 supplies a low-temperature condensation-side heat medium to the water-sealed vacuum pump 50 via the condensation-side low-temperature pipe 6C. Further, the heat pump 6 receives the condensation side heat medium that has become a high temperature by absorbing the heat of condensation when the water vapor is condensed in the water ring vacuum pump 50 via the condensation side high temperature pipe 6D. In some cases, the water-sealed vacuum pump 50 can be insulated. About another structure, it is the same as that of the vacuum dryer M1 which concerns on said embodiment.

  In the vacuum drying apparatus M2 according to the present embodiment, the vacuum drying apparatus M1 according to the first embodiment uses the oil type vacuum pump 2 as a vacuum pump, whereas the vacuum pump is a water-sealed vacuum. The difference is that the pump 50 is used. Since the water-sealed vacuum pump 50 uses sealed water to generate a suction force, air is sucked directly from the drying chamber 11 in the drying tank 1 to form a vacuum state. For this reason, the water vapor discharged from the drying chamber 11 directly flows into the water-sealed vacuum pump 50 and is condensed in the condensation-side heat medium in the water-sealed vacuum pump 50.

  Here, in a general water-sealed vacuum pump, water vapor is condensed by mixing water vapor into a large amount of sealed water, and the evaporation pressure at this time depends on the water temperature of the sealed water. When water vapor is moved from the drying tank 1 using such a water-sealed vacuum pump, the water vapor moved from the drying tank 1 is mixed into the sealed water, and the water vapor is assimilated with the sealed water. As a result, the sealing water is warmed by heat corresponding to the heat of evaporation, the evaporation pressure is increased, and the temperature of the sealing water required for condensation is increased, so that cooling water for cooling the sealing water is required.

  In this respect, in the vacuum drying apparatus M2M2 according to the present embodiment, the temperature of the sealing water required for condensation in order to cool the sealing water rises. Therefore, the condensation side heat medium circulated and supplied from the heat pump 6 as sealing water is used. Use. As a temperature rise countermeasure in a general water-sealed vacuum pump, heat is exchanged between the condensation side heat medium and the evaporation side heat medium in the heat pump 6 by using the condensation side heat medium circulated and supplied from the heat pump 6. be able to. Therefore, since the temperature of the condensation side heat medium can be maintained at a low temperature, the water vapor can be condensed suitably.

  Furthermore, a heat insulating member can be provided as appropriate for the drying tank or piping, or a heating system can be provided. By providing such a heat insulating member, a heating system, etc., it is possible to prevent water vapor from condensing at an inappropriate position in the drying tank or piping.

DESCRIPTION OF SYMBOLS 1 ... Drying tank 2 ... Oil type vacuum pump 3 ... Cold trap 4 ... Upstream flow pipe 5 ... Downstream flow pipe 6 ... Heat pump 6A ... Evaporation side high temperature pipe 6B ... Evaporation side low temperature pipe 6C ... Condensation side low temperature pipe 6D ... Condensation High-temperature side pipe 7 ... Opening and closing valve 8 ... Pressure regulating valve 9 ... Release valve 11 ... Drying chamber 12 ... Heating jacket 13 ... Discharge port 21 ... Pump body 22 ... Oil-water separator 31 ... Condensing heat exchanger 32 ... Water tank 50 ... Water-sealed vacuum pump 51 ... circulation pipe D ... substance to be dried M1, M2 ... vacuum drying device Qa ... outside air heat Qc ... condensation heat Qe ... evaporation heat Tc ... cold trap temperature Te ... drying chamber temperature

Claims (3)

A drying tank for storing a material to be dried and evaporating moisture in the stored material to be dried;
A vacuum pump for reducing the pressure in the drying tank;
A heat pump that absorbs heat of condensation caused by condensation of steam discharged from the drying tank when the inside of the drying tank is decompressed, and supplies the heat to the drying tank.
Between the vacuum pump and the drying tank, a cold trap that condenses the vapor discharged from the drying tank is provided,
The heat pump absorbs the condensation heat of the steam condensed in the cold trap via a condensation side heat medium, and supplies the condensation heat to the drying tank via an evaporation side heat medium ,
The cold trap and the vacuum pump are connected by a pipe, and steam discharged from the cold trap can flow through the pipe.
A pressure regulating valve is provided in the pipe;
In the pressure regulating valve, the water vapor pressure of the drying tank and the cold trap corresponds to the water vapor pressure corresponding to the temperature of the drying chamber, which is the temperature in the drying tank, and the cold trap temperature, which is the temperature in the cold trap. A vacuum drying device that is adjusted to an intermediate value with respect to the water vapor pressure . The vacuum pump is an oil-type vacuum pump;
In the oil-type vacuum pump, oil-water separator is connected, a vacuum drying apparatus according to claim 1.   The vacuum drying apparatus according to claim 1, wherein the heat pump includes a heat exchanger that exchanges heat with outside air.

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