Compressed air dehumidifier

Abstract

To provide a compressed air dehumidifier capable of being operated with good responsiveness even in a high load state by property returning lubricating oil circulated together with a refrigerant from a compressor of a refrigeration cycle to the compressor.SOLUTION: In a compressed air dehumidifier which includes a dehumidifier housing 30 having an evaporator 14 of a refrigeration cycle device 10 installed in the inside, the evaporator 14 is integrally formed with the dehumidifier housing 30 as a plate-type heat exchanger, a refrigerant inlet 14a of the evaporator is disposed at a lower side, and a refrigerant outlet 14b of the evaporator is disposed at an upper side. There are provided: a lubricating oil return piping 20 whose upstream side is connected to a refrigerant piping 15 between an expansion valve 13 and the refrigerant inlet 14a of the evaporator, and whose downstream side is connected to a refrigerant return piping 15a between the refrigerant outlet 14b of the evaporator and a compressor 11; a proportional control solenoid valve 22 which is connected to a portion piped so as to be positioned in a middle part of the lubricating oil return piping 20 and below the refrigerant inlet 14a of the evaporator, and is arranged so as to adjust a flow quantity of return lubricating oil; and a control unit 60 which controls the valve.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention is provided with a refrigeration cycle device including a compressor, a condenser, an expansion valve, and an evaporator, and dehumidifies by cooling compressed air introduced from an air compressor to cause moisture in the compressed air to condense. The evaporator of the refrigeration cycle device is installed inside a dehumidification device housing, the evaporator is integrally formed with the dehumidification device housing as a plate-type heat exchanger, and a refrigerant inlet of the evaporator through which refrigerant is introduced is provided below the evaporator, and a refrigerant outlet of the evaporator through which refrigerant is discharged is provided above the evaporator. The present invention relates to a compressed air dehumidification device.

Background Art

[0002] As an example of a conventional compressed air dehumidification device, an air inlet, an air outlet, a drain outlet, a refrigerant inlet, and a refrigerant outlet are provided, and heat exchange is performed between the compressed air in the first space and the refrigerant in the second space to condense the moisture contained in the compressed air for dehumidification. It includes a plate-type heat exchanger, a control unit for controlling the operation of the refrigeration cycle, a lubricating oil discharge pipe for discharging the lubricating oil staying in the second space to the refrigerant pipe, and a solenoid valve for adjusting the flow rate of the fluid moving in the lubricating oil discharge pipe. When the control unit detects a predefined high-load state, it executes a "first process" of controlling the solenoid valve to increase the flow rate of the fluid moving in the lubricating oil discharge pipe (see Patent Document 1), which has been proposed by the applicant of the present application.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem that we are trying to solve with compressed air dehumidifiers is that, in the case of an evaporator of a refrigeration cycle system composed of a plate heat exchanger, the flow path for the refrigerant is greatly enlarged in the evaporator, resulting in poor return of lubricating oil to the compressor of the refrigeration cycle system. Furthermore, since the solenoid valve provided in the conventional lubricating oil return piping (for example, the lubricating oil discharge piping described in Patent Document 1) is controlled by ON / OFF opening and closing, when it opens, the return lubricating oil flows rapidly, and the refrigerant also flows in a bypass manner, resulting in a problem of rapid dew point fluctuations. Thus, because it is not possible to properly control the return of the appropriate amount of return lubricating oil to the compressor in a timely manner, there is a problem that the compressed air dehumidifier cannot operate with good responsiveness, especially when a large amount of return lubricating oil is generated under high load conditions.

[0005] Furthermore, in the invention described in Patent Document 1, the lubricating oil discharge piping is located below the refrigerant inlet of the evaporator and is directly connected to the evaporator. As a result, a large amount of lubricating oil (return lubricating oil) tends to accumulate in the vertical space at the lower end of the evaporator where the refrigerant inlet of the evaporator and the lubricating oil discharge piping are connected, making it difficult to return the return lubricating oil to the compressor with good responsiveness.

[0006] Therefore, the object of the present invention is to provide a compressed air dehumidifier that can operate with good responsiveness even under high load conditions by appropriately returning the lubricating oil contained in the refrigerant and circulating from the compressor of the refrigeration cycle device to the compressor. [Means for solving the problem]

[0007] To achieve the above objective, the present invention comprises the following configuration. In one embodiment of the compressed air dehumidifier according to the present invention, a refrigeration cycle device comprising a compressor, condenser, expansion valve, and evaporator is installed alongside the dehumidifier housing, and the evaporator of the refrigeration cycle device is installed inside the dehumidifier housing to cool the compressed air introduced from the air compressor and dehumidify the compressed air by condensing the moisture in the compressed air, the evaporator being integrally formed with the dehumidifier housing as a plate-type heat exchanger, the evaporator having a refrigerant inlet for introducing refrigerant on the lower side of the evaporator and a refrigerant outlet for discharging refrigerant on the upper side of the evaporator, the return lubricating oil that is returned to the compressor is connected to the refrigerant piping between the expansion valve and the refrigerant inlet of the evaporator on the upstream side and to the refrigerant return piping which is the refrigerant piping between the refrigerant outlet of the evaporator and the compressor on the downstream side, thereby returning the lubricating oil to the compressor, and the evaporator bypass A lubricating oil return pipe is routed to return the oil to the compressor, and the lubricating oil return pipe is located in the middle of the pipe. 、 refrigerant inlet of the evaporator , and the refrigerant piping between the refrigerant inlet of the evaporator and the expansion valve. Piping positioned below The aforementioned lubricating oil return pipe The system comprises a proportional control solenoid valve connected to a part and arranged to adjust the flow rate of the return lubricating oil, and a control device for controlling the proportional control solenoid valve. Furthermore, the volume of the flow path of the lubricating oil return piping is smaller than the volume of the flow path of the refrigerant return piping, and a capillary tube that restricts the flow of the return lubricating oil returned to the compressor is connected in the middle of the lubricating oil return piping, on the side of the return lubricating oil flow that is closer to the compressor than the part of the lubricating oil return piping to which the proportional control solenoid valve is connected, and the upstream return piping, which is the piping upstream of the return lubricating oil flow that is closer to the proportional control solenoid valve in the lubricating oil return piping, is insulated with an insulating material. .

[0011] Furthermore, according to one embodiment of the compressed air dehumidifier according to the present invention, the device is characterized in that it includes at least one of the following sensors: a discharge pipe temperature sensor for measuring the refrigerant temperature on the refrigerant outlet side of the compressor; a high-pressure sensor for measuring the refrigerant pressure on the refrigerant outlet side of the condenser; and a dew point sensor for measuring the dew point of the secondary compressed air that has been dehumidified by heat exchange with the evaporator in the dehumidifier housing; and the device is connected to the at least one of the sensors, which determines the load state of the refrigeration cycle device based on the detection information of the at least one of the sensors and controls the proportional control solenoid valve according to the load state.

[0013] Furthermore, according to one embodiment of the compressed air dehumidifier according to the present invention, the downstream return piping, which is the piping downstream of the return lubricating oil flow from the proportional control solenoid valve of the lubricating oil return piping, is positioned to be heated by the waste heat of the refrigeration cycle device.

[0014] Furthermore, according to one embodiment of the compressed air dehumidifier according to the present invention, the dehumidifier housing is provided to dehumidify the primary side compressed air introduced from an air compressor by heat exchange and to discharge the dehumidified secondary side compressed air, and a heat exchanger is provided inside the dehumidifier housing in two stages, a first heat exchanger section and a second heat exchanger section, and the first heat exchanger section is provided so as to precool the primary side compressed air and reheat the secondary side compressed air, with the precooling flow path for the primary side compressed air and the reheating flow path for the secondary side compressed air intersecting, and the second heat exchanger section is provided so as to dehumidify the compressed air precooled in the first heat exchanger section by cooling it with the evaporator to cause condensation. [Effects of the Invention]

[0015] The compressed air dehumidifier according to the present invention provides a particularly advantageous effect: by appropriately returning the lubricating oil contained in the refrigerant and circulating from the compressor of the refrigeration cycle system to the compressor, it can operate with good responsiveness even under high load conditions. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram illustrating an example of the configuration of a compressed air dehumidifier according to the present invention. [Figure 2] This is a schematic diagram illustrating an example of the configuration of a plate-type heat exchanger, which is a component of the compressed air dehumidifier according to the present invention. [Modes for carrying out the invention]

[0017] Next, an example of the configuration of the compressed air dehumidifier according to the present invention will be described in detail based on the attached drawings (Figures 1 and 2).

[0018] In the compressed air dehumidifier according to the present invention, the basic configuration includes a refrigeration cycle device 10 equipped with a compressor 11, a condenser 12, an expansion valve 13, and an evaporator 14, and a dehumidifier housing 30 in which the evaporator 14 of the refrigeration cycle device 10 is installed, so as to cool the compressed air introduced from the air compressor and dehumidify the compressed air by condensing the moisture in the compressed air, the evaporator 14 is formed integrally with the dehumidifier housing 30 as a plate-type heat exchanger, a refrigerant inlet 14a for introducing refrigerant into the evaporator 14 is provided on the lower side of the evaporator 14, and a refrigerant outlet 14b for discharging refrigerant into the evaporator is provided on the upper side of the evaporator 14.

[0019] Note that "lower side" (bottom, lower end, lower part) refers to the lower side (bottom, lower end, lower part) in the direction along the vertical. Similarly, "upper side" (top, upper end, upper part) refers to the upper side (top, upper end, upper part) in the direction along the vertical.

[0020] Furthermore, in the compressed air dehumidifier according to the present invention, the upstream side is connected to the refrigerant piping 15 between the expansion valve 13 and the refrigerant inlet 14a of the evaporator, and the downstream side is connected to the refrigerant return piping 15a, which is the refrigerant piping 15 between the refrigerant outlet 14b of the evaporator and the compressor 11, thereby returning the lubricating oil that is returned to the compressor 11 to the evaporator 14 bypass It is equipped with a lubricating oil return pipe 20 that is routed back to the compressor 11.

[0021] Furthermore, the compressed air dehumidifier according to the present invention includes a proportional control solenoid valve 22 connected to a portion of the lubricating oil return pipe 20 that is located in the middle of the pipe and below the refrigerant inlet 14a of the evaporator, and arranged to adjust the flow rate of the return lubricating oil, and a control device 60 that controls the proportional control solenoid valve 22.

[0022] According to this compressed air dehumidifier according to the present invention, the lubricating oil contained in the refrigerant circulating from the compressor 11 of the refrigeration cycle is returned to the evaporator 14 via the lubricating oil return pipe 20. bypassWhen returning to the compressor 11, the lubricating oil return pipe 20 arranged at an appropriate position and the action of the proportional control solenoid valve 22 enable a more appropriate return to the compressor 11, and a particularly advantageous effect is achieved in that the operation can be carried out with good responsiveness even in a high-load state.

[0023] That is, the upstream side of the lubricating oil return pipe 20 is connected to the refrigerant pipe 15 between the expansion valve 13 and the refrigerant inlet 14a of the evaporator, and the proportional control solenoid valve 22 connected to the lubricating oil return pipe 20 is arranged so as to be located below the refrigerant inlet 14a of the evaporator. For this reason, the piping configuration from the lubricating oil return pipe 20 (upstream return pipe 21) upstream of the proportional control solenoid valve 22 through the refrigerant pipe 15 to the refrigerant inlet 14a of the evaporator and the lower part of the evaporator 14 is arranged substantially above the height position of the proportional control solenoid valve 22, and the volume from the refrigerant inlet 14a of the evaporator to the proportional control solenoid valve 22 can be made smaller than, for example, the configuration of the invention described in Patent Document 1.

[0024] According to this, the upstream flow path section of the return lubricating oil composed of the lower part of the evaporator 14 and the lubricating oil return pipe 20 (upstream return pipe 21) upstream of the proportional control solenoid valve 22 through the refrigerant pipe 15 from the refrigerant inlet 14a of the evaporator is located substantially above the height position of the proportional control solenoid valve 22, and the return lubricating oil easily stays preferably upstream of the proportional control solenoid valve 22 due to gravity, and when the proportional control solenoid valve 22 is opened, the return lubricating oil can be smoothly flowed by the pressure of the refrigerant.

[0025] Thus, in addition to being able to smoothly flow the return lubricating oil due to the connection relationship between the proportional control solenoid valve 22 and the upstream flow path section of the return lubricating oil, by being the proportional control solenoid valve 22, when the refrigeration cycle device 10 is determined to be in a high-load state, it is possible to appropriately perform control to return the retained lubricating oil (return lubricating oil) to the compressor 11 with good responsiveness. For example, the load state is determined by the discharge pipe temperature sensor 16, the high-pressure pressure sensor 17, and the dew point sensor 34 described later, the opening degree of the proportional control solenoid valve 22 is controlled according to the load state, and while ensuring the dew point performance by controlling the rotational speed of the compressor 11 by the inverter (control of the electric motor M1), it is possible to control so that the oil level of the lubricating oil in the compressor 11 can be maintained within a normal range.

[0026] That is, instead of simply performing control to return the return lubricating oil returned from the evaporator 14 of the refrigeration cycle device 10 configured as a plate-type heat exchanger to the compressor 11 only during high load, the return lubricating oil can be returned as needed without affecting the dew point, so that the stability and responsiveness of the return amount can be improved. Further, by grasping the state of the refrigeration cycle device 10 from the degree of change in the dew point, the current value (rotational speed) of the compressor 11, etc., it becomes possible to timely return the required amount of oil (return lubricating oil).

[0027] Note that since the solenoid valve provided in the conventional lubricating oil return pipe is an ON / OFF opening and closing control, when it is opened, the return lubricating oil flows suddenly, and accordingly, the refrigerant also flows in a bypass manner, resulting in sudden dew point fluctuations. In contrast, in the present invention, sudden dew point fluctuations can be prevented by the proportional control solenoid valve 22, and the retained lubricating oil (return lubricating oil) can be returned to the compressor 11 with good responsiveness as described above.

[0028] Furthermore, in this embodiment, the volume of the flow path of the lubricating oil return pipe 20 is set to be smaller than the volume of the flow path of the refrigerant return pipe 15a. This allows for a smaller amount of stagnant lubricating oil (return lubricating oil), enabling the return lubricating oil to be returned to the compressor 11 with better responsiveness, and thus maintaining the oil level (required oil amount) of the lubricating oil in the compressor 11 more appropriately. Incidentally, by making a portion of the refrigerant pipe 15, which is the section of piping through which the return lubricating oil is returned from the evaporator 14 to the proportional control solenoid valve 22, and the upstream return pipe 21 as short as possible and connecting them to the proportional control solenoid valve 22, the amount of return lubricating oil can be substantially reduced, thus enabling a more effective return to the compressor 11.

[0029] Furthermore, in this embodiment, a capillary tube 23 is connected to the middle of the lubricating oil return pipe 20 to restrict the flow of return lubricating oil that is returned to the compressor 11. This restricts the flow of return lubricating oil, and as a result, it also restricts the flow of refrigerant that would otherwise be bypassed by the return lubricating oil, thereby preventing sudden dew point fluctuations.

[0030] Furthermore, in this embodiment, the capillary tube 23 is connected to the downstream side of the return lubricating oil flow (the downstream return pipe 24 side), which is on the compressor 11 side of the portion of the lubricating oil return pipe 20 to which the proportional control solenoid valve 22 is connected. As a result, the position of the capillary tube 23 is on the opposite side of the proportional control solenoid valve 22 from the side of the proportional control solenoid valve 22 that is closer to the evaporator 14 and more easily cooled (the upstream return pipe 21 side) of the return lubricating oil flow. This makes it easier to ensure the flow of the capillary tube 23 and allows for a more stable device configuration.

[0031] In this embodiment, the refrigeration cycle device 10 is equipped with at least one of the following sensors: a discharge pipe temperature sensor 16 for measuring the refrigerant temperature on the refrigerant outlet side of the compressor 11; a high-pressure sensor 17 for measuring the refrigerant pressure on the refrigerant outlet side of the condenser 12; and a dew point sensor 34 for measuring the dew point of the secondary compressed air that has been dehumidified by heat exchange with the evaporator 14 in the dehumidifier housing 30. The control device 60 determines the load state of the refrigeration cycle device 10 based on the detection information of at least one of these sensors and controls the proportional control solenoid valve 22 according to the load state. The control device 60 is connected to at least one of these sensors. In addition to controlling the proportional control solenoid valve 22, the control device 60 is also provided to control the operation of the refrigeration cycle device 10 by controlling the electric motor M1 of the compressor 11 and the electric motor M2 of the condenser cooling fan 12a of the condenser 12.

[0032] According to this, the load state can be determined based on data derived from individual detection results or combinations of multiple detection results from the discharge pipe temperature sensor 16, high-pressure sensor 17, and dew point sensor 34. The opening degree of the proportional control solenoid valve 22 can be controlled according to the load state, and the dew point performance can be ensured by controlling the rotational speed of the compressor 11 by an inverter (electric motor control), while maintaining the oil level of the lubricating oil in the compressor 11.

[0033] For example, if the discharge pipe temperature sensor 16 detects that the refrigerant temperature is higher than the set temperature (indicating a high load condition), the proportional control solenoid valve 22 can be adjusted to open according to the degree of the high load to return the return lubricating oil to the compressor 11. Similarly, if the high-pressure sensor 17 detects that the refrigerant pressure (condensation pressure) is higher than the set pressure (indicating a high load condition), the proportional control solenoid valve 22 can be adjusted to open according to the degree of the high load to return the return lubricating oil to the compressor 11. Furthermore, if the dew point sensor 34 (temperature sensor) detects that the compressed air temperature (dew point) is higher than the set temperature (indicating a high load condition), the proportional control solenoid valve 22 can be adjusted to open according to the degree of the high load to return the return lubricating oil to the compressor 11. Conversely, if a low-load condition is detected, the proportional control solenoid valve 22 should be adjusted to close, thereby performing the opposite action to that performed when a high-load condition is detected.

[0034] Furthermore, in one embodiment of the present invention, the upstream return pipe 21, which is the pipe upstream of the proportional control solenoid valve 22 of the lubricating oil return pipe 20 in the flow of the return lubricating oil, can be configured to be insulated with an insulating material. This allows the upstream return pipe 21 to be insulated from the outside air, preventing the occurrence of condensation.

[0035] Furthermore, in an example of the present invention, the downstream return pipe 24, which is the pipe downstream of the return lubricating oil flow from the proportional control solenoid valve 22 of the lubricating oil return pipe 20, can be configured to be heated by the waste heat of the refrigeration cycle device 10. For example, the downstream return pipe 24 can be placed near the inlet pipe of the condenser 12. This allows the return lubricating oil to be appropriately heated, increasing its fluidity, thereby improving the responsiveness of the control of the return lubricating oil flow and stabilizing the amount of return lubricating oil returned to the compressor 11.

[0036] Furthermore, in this embodiment, as shown in Figure 2, the dehumidifier housing 30 is provided as the main body of the heat exchanger unit 50 so as to dehumidify the primary side compressed air (see black arrow in Figure 2) introduced from an air compressor (compressed air source) such as an air compressor by heat exchange, and discharge (supply) the dehumidified secondary side compressed air (see white arrow in Figure 2). Inside the dehumidifier housing 30, a heat exchanger (a plate-type heat exchanger) is provided in two stages: a first heat exchanger section 33 and a second heat exchanger section 40.

[0037] The first heat exchanger section 33 is provided such that it pre-cools the primary compressed air and reheats the secondary compressed air, with a pre-cooling channel 33a for the primary compressed air and a reheating channel 33b for the secondary compressed air intersecting. The second heat exchanger section 40 is provided to dehumidify the compressed air pre-cooled in the first heat exchanger section 33 by cooling it in the evaporator 14 to cause condensation. This allows for rational and efficient cooling and dehumidification of the primary compressed air, as well as suitable reheating and discharge of the secondary compressed air.

[0038] In this embodiment, the second heat exchanger section 40 is provided to introduce primary compressed air from above and discharge secondary compressed air from below, and includes a secondary side communication passage 55 that connects the secondary compressed air from the second heat exchanger section 40 to the first heat exchanger section 33, a gas-liquid separation channel section 45 which is the space below the second heat exchanger section 40 and is formed to allow drain water 70 generated by condensation to drip and accumulate in the lower part, and to connect the secondary compressed air to the secondary side communication passage 55, a drain outlet 35 provided at the lower end of the gas-liquid separation channel section 45 or the secondary side communication passage 55 to discharge the drain water, and a temperature sensor 34 (see Figure 1) with a temperature sensing unit positioned in the upper part of the space of the gas-liquid separation channel section 45 where drain water 70 does not accumulate.

[0039] In this example, the temperature sensor 34 is located in the lower part (bottom) of the dehumidifier housing 30, in the space (flow path space) where the compressed air is cooled by a cooling medium (chilled water or refrigerant flowing through the evaporator 14) in the second heat exchanger section 40, resulting in the lowest temperature. A drain discharge circuit device (not shown), which is a component connected to the control valve 36 of the drain discharge device, is connected to the drain discharge port 35. For example, a drain treatment machine equipped with a gas-liquid separation tank and an adsorption treatment tank (oil-water separator) is connected to this drain discharge circuit device.

[0040] In this embodiment, the first heat exchanger section 33 and the second heat exchanger section 40 are arranged at one horizontal end 51 and the other horizontal end 52 of the dehumidifier housing 30. The first heat exchanger section 33 is configured to allow primary compressed air to flow from bottom to top and secondary compressed air to flow from top to bottom. The secondary communication passage 55 is located in the horizontal middle section of the dehumidifier housing 30 between the first heat exchanger section 33 and the second heat exchanger section 40, and is configured to allow secondary compressed air to flow from bottom to top.

[0041] Furthermore, in the example configuration shown in Figure 2, the first heat exchanger section 33 and the second heat exchanger section 40 are plate-type heat exchangers, and the two are continuously connected to form a heat exchanger unit 50. This allows the compressed air dehumidifier to be configured in a compact and simple form. In addition, since this heat exchanger unit 50 has a box shape, it is a device configuration that allows for efficient use of installation space.

[0042] Next, we will explain the flow of compressed air inside the dehumidifier housing 30 of the example configuration shown in Figure 2. A compressed air inlet 31 and a compressed air outlet 32 ​​are provided at the lower part of the one-end wall portion 51a that forms the end face of one end 51 of the dehumidifier housing 30, which is the side where the first heat exchanger portion 33 is located. A second heat exchanger portion inlet 40a is provided at the upper part of the secondary side communication passage 55, which connects the primary side compressed air from the pre-cooling passage 33a of the first heat exchanger portion 33 to the second heat exchanger portion 40. The gas-liquid separation passage portion 45 and the secondary side communication passage 55 are connected by a secondary side communication passage inlet 55a. Furthermore, a secondary side communication passage outlet 55b is provided at the upper part of the secondary side communication passage 55, which connects the secondary side compressed air from the secondary side communication passage 55 to the reheating passage 33b of the first heat exchanger portion 33.

[0043] According to this configuration, primary-side compressed air is introduced from the air compressor to the first heat exchanger section 33 via the compressed air inlet 31, and from the first heat exchanger section 33 to the second heat exchanger section 40 via the second heat exchanger section inlet 40a. The secondary-side compressed air generated after passing through the second heat exchanger section 40 is then connected to the secondary-side communication passage 55 via the secondary-side communication passage inlet 55a, and then connected to the first heat exchanger section 33 via the secondary-side communication passage outlet 55b. In this embodiment, the compressed air flows from bottom to top in the pre-cooling passage 33a of the first heat exchanger section 33, from top to bottom in the cooled passage 42 of the second heat exchanger section 40, from bottom to top in the secondary-side communication passage 55, and from top to bottom in the reheating passage 33b of the first heat exchanger section 33.

[0044] Furthermore, the other end wall portion 52a forms the end face of the other end side 52 of the dehumidifier housing 30, which is the side on which the second heat exchanger section 40 is located. At the lower part of the other end wall portion 52a, there is an inlet for the cooling medium (refrigerant) in the second heat exchanger section 40 (refrigerant inlet 14a of the evaporator), and at the upper part there is an outlet for the cooling medium (refrigerant) in the second heat exchanger section 40 (refrigerant outlet 14b of the evaporator). Refrigerant is supplied to the inlet for the cooling medium (refrigerant inlet 14a of the evaporator) from a refrigerant supply source (for example, the expansion valve 13 of the refrigeration cycle device 10 shown in Figure 1). In this second heat exchanger section 40, as shown by the gray arrows in Figure 2, the refrigerant flows from the bottom to the top, and the refrigerant flow path 41 and the cooled flow path 42 intersect, thereby cooling the compressed air flowing into the cooled flow path 42 of the second heat exchanger section 40 and causing the moisture in the compressed air to condense. The compressed air flowing through the cooled channel 42 becomes a downward flow, in the same direction as gravity. As a result, the drain water 70 generated by condensation can be smoothly pushed away and discharged / dripped towards the gas-liquid separation channel 45 for collection.

[0045] Furthermore, in this embodiment of the compressed air dehumidifier, an air flow sensor 38 and an air pressure sensor 39 are installed at the compressed air inlet 31 into which the primary side compressed air of the dehumidifier housing 30 is introduced. The control device 60 controls the proportional control solenoid valve 22 as described above, and also determines the load state of the refrigeration cycle device based on the detected flow rate and pressure information of the primary side compressed air detected by the air flow sensor 38 and the air pressure sensor 39. The control device 60 is configured to control the operation of the compressor 11 and the operation of the condenser cooling fan 12a, which is a component of the condenser 12, according to the load state. Note that 12b is a heat dissipation fin.

[0046] Although various preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and many modifications can be made without departing from the spirit of the invention. [Explanation of Symbols]

[0047] 10 Refrigeration cycle equipment 11 Compressor 12 Condenser 12a Cooling fan for condenser 12b Heat dissipation fins 13 Expansion valve 14 Evaporator 14a Refrigerant inlet of the evaporator 14b Refrigerant outlet of the evaporator 15 Refrigerant Piping 15a Refrigerant return piping 16. Discharge pipe temperature sensor 17 High-pressure sensor 20 Lubrication oil return piping 21 Upstream return piping 22 Proportional control solenoid valve 23 Capillary tubes 24 Downstream return piping 30 Dehumidifier housing 31 Compressed air inlet 32 Compressed air outlet 33. First heat exchanger section 33a Flow channel for pre-cooling 33b Reheating channel 34 Dew point sensor 35 Drain outlet 36 Control valve for drain discharge device 38 Air flow sensor 39. Air pressure sensor 40 Second heat exchanger section 40a Inlet of the second heat exchanger section 41 Refrigerant flow path 42 Cooled channel 45 Gas-liquid separation channel section 50 Heat exchanger units 51 One end 51a One end wall 52 Other end side 52a Other end wall 55 Secondary side communication path 55a Secondary side connecting passage entrance 55b Secondary side communication passage outlet 60 Control device 70 Drain water

Claims

1. A refrigeration cycle device comprising a compressor, condenser, expansion valve, and evaporator is installed alongside a dehumidifier housing that houses the evaporator of the refrigeration cycle device, and the evaporator is integrally formed with the dehumidifier housing as a plate-type heat exchanger, with a refrigerant inlet for introducing refrigerant to the lower side of the evaporator and a refrigerant outlet for discharging refrigerant to the upper side of the evaporator, wherein the refrigeration cycle device comprising a compressor, condenser, expansion valve, and evaporator is installed alongside the dehumidifier housing that cools the compressed air introduced from the air compressor to condense the moisture in the compressed air, and the evaporator is integrally formed with the dehumidifier housing as a plate-type heat exchanger, and a refrigerant inlet for introducing refrigerant to the lower side of the evaporator is provided, and a refrigerant outlet for discharging refrigerant A lubricating oil return pipe is provided, with its upstream end connected to the refrigerant piping between the expansion valve and the refrigerant inlet of the evaporator, and its downstream end connected to the refrigerant return pipe, which is the refrigerant piping between the refrigerant outlet of the evaporator and the compressor, thereby allowing the return lubricating oil to be returned to the compressor to bypass the evaporator. A proportional control solenoid valve is connected to a portion of the lubricating oil return piping located in the middle of the lubricating oil return piping, below the refrigerant inlet of the evaporator and the refrigerant piping between the refrigerant inlet of the evaporator and the expansion valve, and is arranged to adjust the flow rate of the return lubricating oil. The system includes a control device for controlling the proportional control solenoid valve, The volume of the flow path of the lubricating oil return pipe is set to be smaller than the volume of the flow path of the refrigerant return pipe. A capillary tube that restricts the flow of the return lubricating oil returned to the compressor is connected in the middle of the lubricating oil return piping, on the downstream side of the return lubricating oil flow, which is closer to the compressor than the part of the lubricating oil return piping to which the proportional control solenoid valve is connected. A compressed air dehumidifier characterized in that the upstream return piping, which is the piping upstream of the return lubricating oil flow from the proportional control solenoid valve in the lubricating oil return piping, is insulated with an insulating material.

2. The dehumidifier includes at least one of the following sensors: a discharge pipe temperature sensor for measuring the refrigerant temperature on the refrigerant outlet side of the compressor; a high-pressure sensor for measuring the refrigerant pressure on the refrigerant outlet side of the condenser; and a dew point sensor for measuring the dew point of the secondary compressed air that has been dehumidified by heat exchange with the evaporator in the dehumidifier housing. The compressed air dehumidifier according to claim 1, characterized in that the control device, which determines the load state of the refrigeration cycle device based on detection information from at least one of the sensors and controls the proportional control solenoid valve according to the load state, is connected to at least one of the sensors.

3. The compressed air dehumidifier according to claim 1, characterized in that the downstream return piping, which is the piping downstream of the proportional control solenoid valve in the lubricating oil return piping, is positioned to be heated by the waste heat of the refrigeration cycle device.

4. The compressed air dehumidifier according to any one of claims 1 to 3, wherein the dehumidifier housing is provided to dehumidify primary compressed air introduced from an air compressor by heat exchange and to discharge the dehumidified secondary compressed air, and a heat exchanger is provided inside the dehumidifier housing in two stages, a first heat exchanger section and a second heat exchanger section, the first heat exchanger section is provided so as to precool the primary compressed air and reheat the secondary compressed air, by arranging the precooling flow path for the primary compressed air and the reheating flow path for the secondary compressed air to intersect, and the second heat exchanger section is provided so as to dehumidify the compressed air precooled in the first heat exchanger section by cooling it in the evaporator to cause condensation.

Images