JPS58221348A - Dehumidifier for compressed air - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is useful for dehumidifying compressed air by cooling it to a temperature below the dew point, when the flow rate or temperature of the compressed air decreases, when the amount of drain increases, or when the compressor Alternatively, the present invention relates to a compressed air dehumidifying device having a device for controlling the operation of the device when the condenser becomes overloaded.

For example, as shown in FIG. 1, a conventional device of this type has an evaporator 2 housed in a cooling tank 1 that forms a flow path for compressed air, and a t-coupler that is installed outside the tank together with the evaporator 2. There is a system in which a refrigerant compressor 3 and a condenser 4 are connected in circulation via a capillary tube (or expansion valve) 5 and an accumulator 6 for dehumidification. However, in such a dehumidifier, if the compressor 3 is started and stopped according to changes in the flow rate and temperature of compressed air, the frequency of starting and stopping of the compressor increases, and the discharge (high pressure) side and suction (low pressure) side When the pressure difference between the compressor and the compressor is large, there is a risk that the compressor will be started and overloaded, or the cooling and dehumidifying capacity may not be able to keep up with the sudden increase in the compressed air load. Accordingly, in the conventional device, as shown in FIG. The cooling temperature of the compressed air was maintained at a predetermined value by controlling the flow rate. 10 is a compressed air inlet, 11 is a compressed air outlet,
12 is a drain trap.

However, adjusting the opening degree of the capacity control valve 9 to adjust the cooling capacity and continuously operating the compressor 3 is a waste of electricity. Since the evaporation pressure increases, the specific volume of the suction gas refrigerant increases, and the shaft power of the compressor increases significantly even in partial load operation, so this type of dehumidifier has the disadvantage of increasing operating costs.

In addition, if dust or the like enters the drain trap 12, the drain valve becomes clogged and malfunctions, causing a large amount of drain to accumulate in the cooling tank 1. As a result, a portion of the accumulated drain flows into the compressed air from the air outlet 11. There was a risk of malfunction of equipment that uses compressed air mixed in with the λ compressed air.

Furthermore, there is a drawback that the drain accumulated in the tank 1 freezes when the compressor or the like is in operation, blocking the drain outlet. Some condensers and compressors have built-in overload protection devices, but such devices require a self-holding circuit to issue an alarm, which has the disadvantage of complicating the circuit. was there. In order to overcome these drawbacks, the inventor of the present application installed a temperature sensor inside the cooling tank to detect temperature changes inside the cooling tank, control the operation of the compressor and condenser fan motor, and control the operation of the fan motor for the compressor and condenser. Japanese Patent Application No. 5723572 discloses a device that stops the compressor and condenser fan motor to issue an alarm based on a signal from a drain amount sensing means provided in the trap, or activates a drain discharge means based on the signal.
proposed in the issue. However, in order to install a temperature sensor such as a thermistor in a cooling tank, which is a type of pressure vessel and in which high-temperature compressed air flows, it must be inserted into the cooling tank through a protective tube with good thermal conductivity. Moreover, in order to keep this protective tube in constant contact with the evaporator fins (or evaporator pipes), drill a hole in the cooling tank, attach it by brazing, screwing, etc., and attach it to the sheet? Furthermore, when storing the temperature sensor in the protection tube, it is necessary to apply a bias force such as a spring so that it is always in contact with the tip of the tube, and to prevent it from being affected by the outside temperature. In order to reduce the amount of noise, the manufacturing process is complicated by including heat sealing of the lead wire from the sensor, which requires skill, which increases manufacturing costs and makes maintenance and inspection of the equipment troublesome. .

The present invention has been made in view of the above, and it simplifies the installation of a temperature sensor, makes temperature detection accurate, and adjusts the flow rate of compressed air and the compressor and condenser according to temperature fluctuations according to the temperature information. etc., to reduce power consumption and enable highly economical operation, as well as detect overload conditions of compressors, etc. and control their operations to improve maintainability.
Furthermore, the purpose is to detect a state in which the drain trap is clogged or malfunctions, and performs drying or automatic discharge to prevent deterioration of the dehumidification effect of the device.

Hereinafter, the present invention will be explained based on illustrated embodiments.

Cooling tank 2 provided with an inlet 21 and an outlet 22 for compressed air
A refrigerant evaporator 24 is installed inside the cooling tank 23, and a refrigerant compressor 25 installed outside the cooling tank 23 and a condenser 26 having a condenser fan motor 26a are connected to the evaporator 24 via a capillary tube 2γ and an accumulator 28. The refrigeration cycle is constructed by connecting the refrigeration system so that it circulates, as in the conventional case. 30 is a drain trap that communicates with the cooling tank 23 via a drain discharge pipe 30a. A drain trap sensing means 31 is installed in the drain trap 30. A preliminary cooling chamber 33 that is air-cooled by an air-cooling fan motor 32 is connected to the air volume 21 of the cooling tank 23 . 34 is an entrance of the preliminary cooling chamber 33.

A temperature sensor 35 for detecting the temperature of the refrigerant is provided in contact with the outlet pipe 29 near where the refrigerant circulating in the refrigeration cycle exits the evaporator (cooling tank) after heat exchange.

36 is a compressor 25. This is an overload detection circuit that obtains an activation signal from a protection device such as an overcurrent relay connected to the condenser fan motor 26 & and the pre-cooling room fan motor 32. Drain wax sensing means 31. The temperature sensor 35 and the overload detection circuit 36 are connected to the compressor 25 and the condenser 26,
It is connected to a control device 38 that controls the operation of the fan motor 32 or the music recorder 3γ, respectively, based on signals from the sensing means. The temperature at which the control device 38 operates based on the signal from the temperature sensor 35 is T! when operating and stopping the compressor, condenser fan motor, and preliminary cooling room fan motor, respectively. , T2℃(TI Eating is a warning! 370) Alarm * n stop nitsui”'Cha Vl
*Vz (Vt>Vz) Otsu naru! Yes, it is set to . As the drain ffi sensing means 31, the third
As shown in the figure, the electric resistance between the electrode tube 31B vertically connected to the drain trap 30 and the electrode rod 31c inserted downward from the top of the electrode tube through the insulator 31b A device that measures capacitance C is conceivable. In this case, the control device 38 determines the value of resistance or capacitance based on the signal from the drain amount sensing means in order to determine whether the alarm 37 is in danger or stopped.
) or O1+02 (Of >Ox).

When the amount of drain increases, the control device 38 activates the alarm 37 and stops the compressor, etc., but instead of these, +5. . . . The operation of a solenoid valve 40 provided at the outlet 39 of the drain trap 30 shown in FIG. 4 may be controlled.

Further, as shown in FIG. 5, the overload detection circuit used in the present invention includes a contact operated by the electromagnetic contactor 41 between the power supplies A and B, an electromagnetic contactor 41, a high pressure switch 42, and a motor protector 43. The compressor 25, the condenser fan motor 26a, and the pre-cooling chamber fan motor 32 are connected in parallel via 41&, and the light emitting element 44 is connected in parallel with the motor protector 43 and the high pressure switch 42, and is opposed to the light emitting element 44. There is a light-receiving element 45 that sends a signal to the control device 38 at the position where the light is detected. In addition, the drain amount detection means 31 and the overload detection circuit 36 are shown in FIG.
It is not limited to what is shown in the figure, but any type may be used as long as it performs a predetermined function.

The main shaft device constructed as described above operates as follows.

The compressed air flowing in through the air inlet 34 of the preliminary cooling chamber 33 enters the hard cooling tank 23, which is precooled by the motor 32. In the tank, the refrigerant evaporates in the evaporator 24 having cooling fins. Therefore, the compressed air flowing in the cooling tank is cooled to below the dew point by the heat of evaporation, dehumidified, and flows out from the outlet 22. Drain generated by the dehumidification passes through the drain discharge! 308 and drains into the drain trap 30.
It accumulates in

When the flow rate of compressed air decreases or the temperature decreases and the heat load decreases, frost formation occurs on the surfaces of the cooling coils and cooling fins in the cooling tank. Then, the refrigerant temperature at the outlet of the evaporator 24 decreases. When the temperature of the refrigerant drops to below 1000, it is detected by a temperature sensor 35 installed on the outlet pipe 29 of the evaporator, and the detected temperature is sent as a signal to the control device 38, which operates the compressor 25. The condenser fan motor 26a and the preliminary cooling chamber fan motor 32 are stopped. Then, as time passes, the flow rate of the compressed air increases, or the temperature of the compressed air increases and the heat load increases, the frost adhering to the cooling fins begins to melt. However, even if the compressor is stopped, the compressed air is cooled by the heat of fusion until the melting is completely completed, so the cooling and dehumidifying functions are maintained. However, after the frost completely melts, the temperature of the compressed air leaving the cooling tank rises, and the temperature of the evaporator outlet pipe 29 also rises. When the temperature reaches T1, the detected temperature is detected by the control device 3.
8 as a signal, the device is activated and the compressor 25 and each fan motor 26 & 32 start operating.
If the compressor or the like stops operating at the temperature It Tm detected by the temperature sensor, the difference between the compressed air and the outside temperature will be reduced, and no significant precooling effect can be expected. Therefore, in the above embodiment, the operations of the compressor, the condenser fan motor, and the pre-cooling room fan motor are stopped at the same time. However, depending on the set temperature T2, if a pre-cooling effect can be expected, Further, another control temperature may be set for operation and stop of the controller.

As described above, in the apparatus of the present invention, the operations of the compressor, condenser, and precooling chamber are controlled according to the refrigerant temperature near the outlet of the evaporator. FIG. 6 shows the relationship between the temperature T detected by the temperature sensor 35 and the operating device.

Next, the operation of the drain pinching means will be explained. The compressed air flowing in from the air supply 34 is cooled and dehumidified in the cooling tank 23 to form a drain. This drain accumulates in the drain trap 30 via the drain discharge pipe 30a. And if the drain trap 30 is blocked,
The water level gradually rises and the drain amount reaches ■l. Then, the drain ms means 31 detects the IO, and a signal is sent to the control device 38, which activates the alarm 37 and stops the operation of the compressor and each fan motor 26B, 32. Fourth
As shown in the figure, when the solenoid valve 40 is operated by the control device 38, the solenoid valve 40 opens and drains water automatically. Further, when the drain is drained and the amount in the drain trap 30 becomes less than 2, the drain sensor 31 detects this and sends a signal to the control device, which activates the alarm 31 and stops the compressor 25. And the operation of each fan motor 26 & 32 is started. In addition, when the solenoid valve 40 is controlled by the control device 38 as shown in FIG. 4, the solenoid valve 40 is closed and drainage is stopped.

As described above, in the present device, the operation of the compressor, the condenser fan motor, the preliminary cooling room fan motor, and the alarm or solenoid valve is controlled according to the amount of water in the drain trap 30. FIG. 7 shows the relationship between the drain fiV sensed by the drain amount sensing means and the operating device.

Next, the operation of the overload detection circuit 36 will be explained. When the pressure inside the compression chamber of the compressor increases and becomes high pressure, when the compressor becomes abnormally high or warm, or when an overcurrent occurs. In case of overload condition, the overload detection circuit 36
The contacts of the protection device inside are opened, and the compressor, condenser fan, and precooling room fan are stopped independently of the control device 38.1. At this time, the overload detection circuit 36 detects the open state of the contact of the protection device and sends a signal to the control device 38, which operates and the alarm 31 issues an alarm.

As described above, according to the present invention, the compressor etc. are operated and stopped according to the temperature of the refrigerant after heat exchange with compressed air in the evaporator, and the heat of fusion of the frost attached to the evaporator is used when the evaporator is stopped. Since it is designed to effectively utilize the cooling capacity, the operating time of the compressor can be shortened and operating costs can be saved. Furthermore, since the fan motors of the condenser and pre-cooling chamber are also stopped, the operation time of the fan motors can be shortened and operating costs can be saved, and there is no need to install a dedicated sensor, simplifying the circuit. It is measured. In the present invention, the temperature sensor also includes a cooling tank (evaporator)
Since the sensor is installed in the piping between the compressor and the compressor, it is extremely easy to install the sensor.For example, the thermistor can be tightly attached to the piping with adhesive tape and then heat-sealed with heat insulating material. Compared to installing inside a cooling tank, the manufacturing process is significantly reduced, material costs are small, maintenance and inspection of the equipment is also simplified, and unlike installing inside a cooling tank through a protection tube, heat transfer Since there is no air layer in the path, the refrigerant temperature is quickly and accurately reflected on the temperature sensor.

This eliminates most of the variation in temperature detection performance due to sensor installation. In addition, the compressor etc. is configured to start and stop depending on the temperature T1 + T2 detected by the temperature sensor, but when the heat load is low, it starts and stops.
The interval between stops may be as short as about 1 to 2 minutes, but even in this case, by setting the starting temperature T1 such that the temperature of the refrigerant that the compressor sucks from the accumulator 28 at the time of starting is low. The temperature rise caused by the starting current of the motor that drives this can be suppressed by the suction refrigerant gas, and it can be operated without problems even when the heat load is small. Therefore, there is no need to delay the start-up time using a timer or the like as in the conventional case, and it is possible to immediately respond to sudden heat loads. Furthermore, the device according to the present invention senses the amount of condensate in the drain trap, stops the compressor, etc., activates the alarm, or controls the solenoid valve to automatically drain the drain. It is possible to prevent the occurrence of a situation where ice forms and blocks the inside of the tank. In addition, when opening and closing the drain outlet by controlling the electromagnetic valve, continuous operation is possible without stopping the operation of the compressor and the like.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a conventional example, Fig. 2 is a schematic diagram showing an embodiment of the present invention, and Fig. 6 is a schematic diagram showing an embodiment of the drain amount sensing means of the device according to the present invention. , Fig. 4 is a schematic diagram showing an example in which a solenoid valve is used at the drain outlet of the device according to the present invention, @ Fig. 5 is a circuit diagram showing an example of the overload detection circuit according to the present invention, and Fig. 6 The figure is a correlation diagram showing the relationship between the temperature detected by the temperature sensor and each operating device. Figure 7 is the correlation diagram showing the relationship between the detected drain amount by the drain amount sensing means and the compressor, alarm 2wL magnetic valve, and fan motor. It is a diagram. Patent applicant Orion Machinery Co., Ltd. Figure 1 Figure 2 Procedural amendment (voluntary) 1. Indication of the case 1982 Patent Application No. 86780 Relationship to the case Patent applicant 4, agent 6, Increased due to amendment number of inventions

Claims (1)

[Scope of Claims] (1) A refrigeration cycle is constructed by cyclically connecting a refrigerant compressor, a condenser, a capillary tube, an evaporator, and an accumulator, and the evaporation occurs in a cooling tank that constitutes a flow path for compressed air. It consists of a device configured to dehumidify by installing a dehumidifier, and a control device that controls the operation of the compressor and condenser fan motor that are the driving parts of the device, and the control device controls the operation of the evaporator and compressor of the refrigeration cycle. A compressed air dehumidifying device characterized in that it is configured to be activated by a signal from a temperature sensor installed in a pipe between the compressed air dehumidifying device and the compressed air dehumidifying device. (2) An air-cooled preliminary cooling chamber by a fan motor is connected to the air inlet of the cooling tank, and the operation of the fan motor is controlled by a control device based on a signal from a temperature sensor. A compressed air dehumidifier according to claim 1. (6) A refrigerant compressor, a condenser, a capillary tube, an evaporator, and an accumulator are connected in circulation to form a refrigeration cycle, and the evaporator is installed in a cooling tank that forms a flow path for compressed air. It consists of a device configured to dehumidify, a compressor that is a drive part of the device, a control device that controls a condenser fan motor, an alarm, or a solenoid valve, and the control device controls the evaporator and compressor of the refrigeration cycle. The operation of the compressor and condenser fan motor is controlled by a signal from a temperature sensor installed in the piping between 1. A compressed air dehumidification device, characterized in that the device is configured to control the operation of a fan motor or a solenoid valve for a condenser and a condenser. (4) The drain amount sensing means detects the drain by the electric resistance or capacitance between the electrode tube vertically connected to the drain trap and the electrode rod inserted below the workpiece from above the electrode tube through the insulator. 7. A compressed air dehumidifying device according to claim 6, characterized in that the compressed air dehumidifier is configured to sense the amount. (5) An air-cooled pre-cooling chamber by a fan motor is connected to the air inlet of the cooling tank, and the operation of the fan motor is controlled by a control device based on a signal from a temperature sensor or a drain amount sensing means. A compressed air dehumidifying device according to claim 6 or 4, characterized in that: (6) A refrigeration cycle is constructed by cyclically connecting a refrigerant compressor, condenser, capillary tube, evaporator, and accumulator, and dehumidification is achieved by installing the evaporator in a cooling tank that forms a flow path for compressed air. and a control device that controls the compressor and condenser fan motor that are the driving parts of the device, as well as an alarm, and the control device is connected to piping between the evaporator and the compressor of the refrigeration cycle. The operation of the compressor and condenser fan motor is controlled by the signal from the temperature sensor installed in the A compressed air dehumidifier, characterized in that it is configured to control the operation of an alarm by a signal from a load detection circuit. (7) An air-cooled preliminary cooling chamber by a fan motor is connected to the air intake port of the cooling tank, and the operation of the fan motor is controlled by a control device based on a signal from a temperature sensor. The compressed air dehumidifier according to scope 6. (8) The compressed air dehumidifier according to claim 7, wherein the pre-cooling room fan motor is similarly connected to an overload detection circuit connected to the compressor and condenser fan motors.