JP2880478B2 - Drain discharge controller of refrigeration air dryer and refrigeration air dryer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration air dryer having a drain discharge controller and a refrigeration air dryer for removing moisture from compressed air.

[0002]

2. Description of the Related Art Compressed air is usually produced by compressing the atmosphere using an air compressor in order to operate various kinds of pneumatic equipment, and is supplied to a place of use using an air pipe. However, since the air compressor simultaneously sucks and compresses moisture in the atmosphere together with the atmosphere, a large amount of water vapor is contained in the compressed air. In addition, the amount of water vapor in the atmosphere is not always constant, but changes depending on the temperature. In particular, when the temperature drops drastically, condensation of the water vapor starts to generate drain (water droplets). If this drain is supplied to various types of pneumatic equipment, it will cause a failure, so it is necessary to forcibly remove the drain.

[0003] Therefore, an air dryer has been conventionally used for drain removal. This air dryer has
There are a refrigeration air dryer, a desiccant dryer, and a hollow fiber membrane dryer, and the obtained dew points are different from each other. Here, a refrigeration air dryer most frequently used in a general pneumatic circuit will be described. Incidentally, the dew point of the refrigeration air dryer is generally −17 ° C. in the atmospheric pressure state and 10 ° C. in the compressed air state.

In the refrigeration air dryer 50, as shown in FIG. 12, refrigerant, which is a refrigerant, is always circulated, and two types of heat exchangers 51, 52 and a compressor 57 are arranged in the circulation circuit. . The heat exchangers 51 and 52 include a condenser 51 and an evaporator 52.
Are provided with a compressed air inlet and outlet and a drain discharger 54, and a condenser 51 is provided with a cooling device 55. The condenser 51 includes an air-cooled type in which cooling is performed by a cooling fan and a water-cooled type in which cooling water is circulated and cooled. The refrigeration air dryer 50 shown in FIG. 12 is an air-cooled type. Further, a precooler 53 for pre-cooling the compressed air is installed before the evaporator 52.

[0005] Next, the operation of the refrigeration air dryer 50 will be described. First, compressed air produced by an air compressor (not shown) is supplied to a refrigeration air dryer 5.
The compressed air that has passed through the precooler 53 from the inlet of the evaporator 53 and is precooled is supplied into the evaporator 52. This compressed air is moist air containing water vapor. On the other hand, the CFC is cooled by the condenser 51 to become a liquid, and is decompressed to an appropriate amount by the capillary tube 56.
2. Then, since the Freon is warmed and evaporated by the compressed air, the surrounding air is deprived of heat by the latent heat of evaporation, so that the compressed air is cooled, and the condensation of water vapor in the compressed air starts to generate drain. The dried compressed air from which the water vapor has been removed passes through the evaporator 52 and the precooler 53, is discharged from the outlet of the refrigeration air dryer 50, and is supplied to various pneumatic devices.

The CFC that has passed through the evaporator 52 is in a gaseous state, is compressed by a compressor 57, and is supplied to the condenser 51 in a high-pressure gas state. And
The condenser 51 uses a cooling device (fan) 55,
Cools high pressure gaseous Freon. Then, since the heat is released from the fluorocarbon, condensation occurs, and the fluorocarbon liquefies. Then, the pressure is reduced again by the capillary tube 56 and supplied into the evaporator 52. Thereafter, the cycle of vaporization / liquefaction is similarly repeated. The adjustment valve 59 in FIG. 12 is a valve for adjusting the pressure in the evaporator 52 when the supply amount of the compressed air to the evaporator 52 changes, and prevents overcooling in the evaporator 52.

The drain generated in the evaporator 52 is discharged to the outside by a drain discharger 54.
Manually discharging the drain without adversely affecting the pneumatic equipment requires considerable man-hours for maintenance and management, and it is difficult to discharge the drain at the appropriate time. Generally, an automatic drain discharger that automatically discharges drain is used as a discharger.
At present, three types of automatic drain dischargers are used: a mechanical drain discharger, a solenoid valve (or electric valve, hereinafter the same) type drain discharger, and an interval type drain discharger. Therefore, the operation of each drain discharger will be described with reference to FIGS.

First, FIG. 13 shows a mechanical drain discharger.
This will be described with reference to FIG. The mechanical drain discharger 60 includes a body 61 in which a drain chamber 62 for storing drain is formed, a drain valve 63, a pilot valve 64, and a float 65. When the water accumulates in the drain chamber 62 and the water level reaches a certain level or more, the pilot valve 64 opens due to the buoyancy of the float 65, and compressed air is supplied to the piston chamber 66. Then, the piston 67 is pushed up, the drain valve 63 is opened, and the drain is discharged from the discharge port 68. When the drain is discharged, the water level falls, so that the float 65 descends, the pilot valve 64 is closed, and the piston chamber 66
The supply of compressed air to the pump is stopped, the piston 67 descends, and the drain valve 63 closes. Then, the drain again collects in the drain chamber 62, and thereafter, the drain is similarly discharged.

Next, FIG. 1 shows a solenoid valve type drain discharger.
This will be described with reference to FIG. The solenoid valve type drain discharger 70
It is composed of a solenoid valve 4 and a timer 71. The solenoid valve type drain discharger 70 is provided with a timer 7 regardless of the drain amount.
The drain is discharged to the outside by opening the solenoid valve 4 at regular intervals using the number 1.

Finally, the interval type drain discharger will be described with reference to FIG. The interval type drain discharger 80 includes two solenoid valves 4a and 4b, a tank 82 installed between the solenoid valves 4a and 4b, and a timer 81. This interval type drain discharger 80 also has a timer 8 like the solenoid valve type drain discharger 70.
First, the solenoid valve 4a is opened, the drain is collected in the tank 82, and then the solenoid valve 4a is closed and the solenoid valve 4b is opened.
Is opened, the drain in the tank 82 is discharged to the outside.

[0011]

However, the above 3)
The following types of drain dischargers have the following problems. That is, in the mechanical drain discharger 60, the drain is discharged by opening and closing the drain valve 63 mechanically by utilizing the buoyancy of the float 65. 64 and drain valve 63
There is a problem that the opening and closing of the nozzle cannot be performed normally, and the drain cannot be reliably discharged.

In addition, since the solenoid valve type drain discharger 70 discharges regardless of the drain amount, when the drain amount is small (when the inlet temperature is low), the compressed air is also discharged. Large air loss during discharge. Therefore, the amount of air at the outlet side of the refrigeration air dryer 50 decreases, so that the pressure fluctuates, which has a problem of adversely affecting the pneumatic equipment. Further, since the flow rate of the compressed air flowing into the evaporator 52 increases due to the air loss, the heat load of the cooling system fluctuates and the dew point becomes unstable.

On the other hand, the interval type drain discharger 80
Solves the problem of the solenoid valve type drain discharger 70 described above, but uses two solenoid valves (4a and 4b) and also requires a tank 82, which is expensive. . In addition, two outputs of the timer 81 are required,
There is also a problem that a circuit for controlling the operation of the solenoid valves 4a and 4b becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a highly reliable drain discharger with a small air loss at the time of drain discharge and a refrigeration air dryer which can be easily manufactured at low cost. An object of the present invention is to provide a drain discharge controller and to provide a refrigeration air dryer having a highly reliable drain discharge device with a small air loss at the time of drain discharge at low cost.

[0015]

According to the first aspect of the present invention, there is provided a drain of a refrigeration type air dryer for removing water from compressed air and discharging the water from a drain discharger. In the discharge controller, temperature detection means for detecting the inlet temperature of the compressed air to the refrigeration air dryer, drain control means for controlling the operation of the drain discharger by a detection signal from the temperature detection means,
It is characterized by having.

According to a second aspect of the present invention, in order to solve the above problem, in the drain discharge controller of the refrigeration air dryer according to the first aspect, the drain control means controls the drain discharge in conjunction with the detection signal. It is characterized in that the time interval of the drain discharge start of the vessel is changed.

The compressed air supplied to the refrigeration air dryer is in a saturated state, and the amount of the saturated steam contained in the air depends on the temperature of the air. As shown in FIG. The logarithms of the quantities are approximately proportional.
Therefore, by detecting the inlet temperature of the refrigeration air dryer, the amount of saturated steam can be calculated. on the other hand,
Most of the saturated steam contained in the compressed air supplied to the refrigeration air dryer is condensed in the evaporator of the refrigeration air dryer to form a drain. Therefore, since the amount of saturated steam becomes the amount of drain, the amount of drain can be determined by detecting the inlet temperature of the refrigeration air dryer and calculating the amount of saturated steam. Therefore, a drain discharge start time corresponding to the drain amount can be set. As described above, by detecting the inlet temperature of the refrigeration air dryer, only the drain can be appropriately discharged, and a drain discharge controller that performs highly reliable drain discharge without air loss can be provided. For this reason, the life of the drain discharger is prolonged, and the maintainability is improved.

Here, the operation control of the drain discharger includes a method of controlling the drain discharge time with a constant drain discharge start time, a method of controlling the drain discharge start time with a constant drain discharge time, and a method of starting the drain discharge. There is a method of controlling both the interval and the drain discharge time.

According to a third aspect of the present invention, in order to solve the above problems, in the drain discharge controller of the refrigeration air dryer according to the second aspect, a thermistor is used as the temperature detecting means, and a timer I is used as the drain controlling means.
C is used.

As the thermistor, there is an NTC thermistor having such characteristics that the resistance decreases as the temperature increases and the resistance increases as the temperature decreases (see FIG. 5). By using this NTC thermistor as a temperature detecting means and combining it with a timer IC, the time interval of drain discharge start can be easily changed in conjunction with the inlet temperature. Therefore, the operation of the drain discharger can be controlled so that only the drain is discharged and there is no air loss, and the production can be made very simply and inexpensively. Although it is possible to use a PTC thermistor having the opposite characteristic to that of the NTC thermistor, the control circuit becomes more complicated than when the NTC thermistor is used.
It is desirable to use a thermistor.

According to a fourth aspect of the present invention, in order to solve the above-mentioned problems, the drain discharge controller for a refrigeration air dryer according to any one of the first to third aspects is characterized in that the time interval of the drain discharge start is set. It is characterized by having a simple load factor meter that calculates a reciprocal and calculates and displays a simple flow rate.

The air compressor connected to the refrigeration air dryer usually has an aftercooler inside, and the relationship between the aftercooler outlet temperature and the air flow rate is as shown in FIG. From FIG. 9, it can be considered that the aftercooler outlet temperature and the air flow rate are almost proportional to each other in the normal compressor use range, and that the aftercooler outlet temperature increases as the air flow rate increases. Further, since the air compressor and the refrigeration air dryer are installed close to each other, the aftercooler outlet temperature can be considered as the inlet temperature of the refrigeration air dryer. Therefore, since the aftercooler outlet temperature is proportional to the air flow rate, the aftercooler outlet temperature is proportional to the amount of saturated steam, and the amount of saturated steam is inversely proportional to the drain discharge time interval, the inverse of the drain discharge time interval is obtained. Will be proportional to the air flow rate. Therefore, by obtaining the reciprocal of the time interval of the drain discharge start, the simple air flow rate can be calculated, and the flow rate can be easily known without installing a flow meter.

According to a fifth aspect of the present invention, there is provided a refrigeration air dryer for removing moisture in compressed air in order to solve the above problems. It has a drain discharge controller.

According to the refrigeration air dryer having the above configuration, the drain discharge controller of the refrigeration air dryer can be manufactured at a low cost with a low air loss at the time of drain discharge and a highly reliable drain discharger. Thus, a highly reliable refrigeration air dryer with low air loss can be provided at low cost.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A drain discharge controller of a refrigeration air dryer according to the present invention will be described in detail with reference to the accompanying drawings, taking concrete embodiments. First,
A drain discharge controller of a refrigeration air dryer according to the first embodiment will be described with reference to the drawings. FIG. 1 is a system diagram of the drain discharge unit, and FIG. 2 is a block diagram of the control. The drain discharge controller 1 includes a temperature sensor 2 that measures an inlet temperature T of the refrigeration air dryer,
A drain control means for transmitting an operation signal for operating a solenoid valve for discharging drain based on a detection signal from the temperature sensor. Here, both the temperature sensor 2 and the solenoid valve 4 are commonly used.

Next, the operation of the drain discharge controller 1 configured as described above will be described. As shown in FIG. 2, the temperature sensor 2 measures the inlet temperature T, and calculates the index changes from the measured values (function (A)) to calculate the saturated water vapor amount W _s (step (hereinafter, simply "S" Written as
1). That is, the function (A) corresponds to the transfer function in S1, and the function (A) is obtained from the saturated water vapor amount table. Then, it calculates the inverse changes from a saturated water vapor content W _s calculated in S1 (function (B)) to calculate the time interval T _int start draining (S2). Then, based on the drain discharge start time interval T _int calculated in S2, an operation signal is transmitted from the drain control means 3, and the solenoid valve 4 for discharging drain operates. Note that the transfer function in S2 is a function (B).

Here, the processing of S2 will be described in more detail with reference to FIG. By setting the design reference temperature T _R First, the basis of the saturated water vapor amount W _sR at that time. In the present embodiment, the reference value is set to “1” (see Table 1). Then, the relative value of the saturation vapor content W _s at each temperature with respect to the reference value is determined. Then, when calculating the reciprocal of the relative value of the saturated water vapor amount W _s, the relative value of the time interval T _int start drainage (Table 1 (1)) can be calculated. This calculation is performed by the function (B). If the saturated water vapor amount W _s is larger than the reference point R, the drain discharge time interval T _int becomes T _int > T _{int R,} and if the saturated water vapor amount W _s is small, the drain discharge time is smaller. The time interval T _int is T _int <T
_intR , and the pulse waveform transmitted from the drain control means 3 becomes a waveform as shown in FIG.

It should be noted, the design reference temperature T _R is the inlet temperature at the operating conditions of the refrigeration air dryer may be selected temperature in the vicinity of the center. In the present embodiment, the design reference temperature T _R is set to T _R = 55 ° C. for the use condition range of 30 to 80 ° C.
Shows the relationship between the time interval T _int saturated water vapor content W _s and drainage starts for each inlet temperature at this time in the following table.

[0029]

[Table 1]

In Table 1, if an actual drain discharge start time interval T _intR at 55 ° C. is set, this value can be easily multiplied by the relative value (1) of the drain discharge start time interval T _int. The time interval T _{int of the} start of drain discharge with respect to the temperature can be obtained. Further, since the time interval T _{int of the} start of drain discharge is inversely proportional to the saturated water vapor amount W _s , when the inlet temperature T rises, that is, when the saturated water vapor amount W _s increases, the time period of the drain discharge start is increased. The interval T _int becomes shorter, and conversely, when the inlet temperature T decreases, that is, when the saturated water vapor amount W _s decreases, the time interval T _{int for} starting drain discharge becomes longer. Thus, it is possible to control such relative increase or decrease of the saturated water vapor content W _s by detecting the inlet temperature T, increases or decreases the time interval T _int start properly draining.

Therefore, since the saturated water vapor amount W _s corresponds to the drain amount, by detecting the inlet temperature T, it is possible to control so as to discharge the drain in accordance with the drain amount. Therefore, it is possible to provide a drain discharge controller that can discharge only the drain properly and that performs highly reliable drain discharge without air loss. Also,
The service life of the drainer is prolonged, and maintenance is improved.

Next, a drain discharge controller according to a second embodiment will be described with reference to FIG. The drain discharge controller 11 uses a NTC thermistor 12 as a temperature sensor for measuring the inlet temperature T of the refrigeration air dryer.
The drain control means 13 for transmitting an operation signal for operating the electromagnetic valve 4 for discharging drain based on the detection signal from the temperature sensor is constituted by the timer IC 14 and the photocoupler 10. The timer IC 14 transmits a pulse signal, and the transmission interval of the pulse signal is N
Determined by the product of the capacitance C _E of the resistance value R _s and the timer IC14 of TC thermistor 12. This pulse signal is sent to the electromagnetic valve 4 via the photocoupler 10, and the electromagnetic valve 4 is operated based on the pulse signal to discharge the drain. Here, the resistance R _s of the NTC thermistor 12
The relationship between the capacitor C _E (corresponding to a time constant) of the timer IC 14 and the interval between pulse signals transmitted to the solenoid valve 4, that is, the time interval T _{int of the} start of drain discharge, is T _int = D R _s · C _E (1) D is a constant.

The inlet temperature T and the NTC thermistor 12
The relationship between the resistance value R _s and the saturated water vapor amount W _s of FIG.
It becomes as shown in. Further, Table 1 shows the design reference temperature T
_{When R} is 55 ° C. (the reference value is “1”), the relative value of the saturated water vapor amount W _s to the inlet temperature T and the relative value of the resistance value R _s of the NTC thermistor 12 (Table 1 (2)) Shows the relationship. From FIG. 5, the resistance value R of the NTC thermistor 12 is shown.
_It can be seen that _s is substantially inversely proportional to the saturated water vapor amount Ws. Therefore, when the inlet temperature T rises, that is, when the saturated water vapor amount W _s increases, the resistance of the NTC thermistor 12 is not completely inversely proportional to the function (B) shown in the first embodiment. value R _s is reduced. Therefore, when the saturated water vapor amount W _s increases, the time interval T _{int of the} start of drain discharge becomes:
Since D and _CE are constant, the length becomes shorter. Conversely, when the saturated water vapor amount W _s is decreased, the time interval T starting drainage
_int is the resistance value R _s of the NTC thermistor 12 increases, longer.

As described above, when the inlet temperature T is detected by using the NTC thermistor 12, the inlet temperature T
Since the resistance value R _s of the TC thermistor 12 is inversely proportional and the saturated water vapor amount W _s is proportional to the inlet temperature T, drain discharge is started appropriately in response to an increase or decrease in the saturated water vapor amount W _s. Can be controlled to increase or decrease the time interval T _int . Therefore, since the saturated water vapor amount W _s is equivalent to the drain amount, by detecting the inlet temperature T, as in the first embodiment, it is possible to control the proper drainage without air loss. Further, since the drain discharge controller 11 includes the NTC thermistor 12 and the timer IC 14, the drain discharge controller 11 can be provided at a low cost with a very simple control circuit.

As described above, by detecting the inlet temperature T using an NTC thermistor, the saturated water vapor amount W _s is determined, and accordingly, the time interval T _{int for} starting drain discharge is determined.
Has been described, but here,
Furthermore, by detecting the inlet temperature T, the air flow entering the refrigerated air dryer (hereinafter, referred to as "dryer flow rate".) Without detecting a Q _d, time interval starting drainage to follow a certain flow rate The following describes that T _int is controlled. FIG. 6 shows a general system diagram of an air compressor and a refrigeration air dryer. The relationship between the dryer flow rate Q _d and the inlet temperature T in the system shown in Figure 7. Here, FIG. 7 shows data obtained by an experiment performed by the inventors. As shown in FIG. 7, the inlet temperature T when the dryer flow rate Q _d is decreased to decrease. Conversely, the inlet temperature T when the dryer flow rate Q _d is increased to increase. Therefore, detecting only the inlet temperature T, without detecting the dryer flow rate Q _d, corresponding to the increase or decrease of the dryer flow rate Q _d seen that it is possible to control the time interval T _int start draining. Therefore, by detecting the inlet temperature T of the refrigeration air dryer, not only the saturated water vapor amount W _s but also the
It will have been also estimated the dryer flow rate Q _d. That is, by detecting the inlet temperature T of the refrigeration air dryer, it is possible to estimate both the saturated water vapor amount W _s and dryer flow rate Q _d is a factor that determines the time interval T _int start draining. As described above, the drain discharge controller 11 according to the second embodiment has a very simple circuit configuration, but can sufficiently estimate the condition of the air flowing into the refrigeration air dryer.

Next, a drain discharge controller according to a third embodiment will be described with reference to FIG. Third
The second embodiment is a drain discharge controller having the function of the drain discharge controller 1 according to the first embodiment, and capable of measuring a simple flow rate. The drain discharge controller 21 transmits an operation signal for operating the temperature sensor 2 for measuring the inlet temperature T of the refrigeration air dryer 50 and an electromagnetic valve 4 for discharging drain based on the detection signal from the temperature sensor 2. Drain control means 3
And a flow rate calculating means 20 for calculating a simple flow rate.

An air compressor (not shown) for supplying compressed air is connected to the refrigeration air dryer 50. This air compressor usually has an aftercooler inside. When the aftercooler is not built in the air compressor, it is installed between the air compressor and the refrigeration air dryer 50. An aftercooler is a heat exchanger that cools compressed air heated by compression to remove moisture in the compressed air.

Regarding the operation of the drain discharge controller 21 configured as described above, the control method for operating the solenoid valve 4 is the same as that of the first embodiment, and therefore will not be described. explain. As mentioned above, aftercooler exit temperature T _A and the air flow rate Q
Since the relationship between a relationship shown in FIG. 9, in the conventional compressor temperature range, the aftercooler exit temperature T _A and the air flow rate Q, there substantially proportional, aftercooler outlet temperature the air flow rate Q is increased It can be considered that T _A increases. The air compressor from being installed in the upcoming Refrigerated air dryer 50, the aftercooler exit temperature T _A may be considered as the inlet temperature T of the refrigerated air dryer 50.

[0039] Therefore, it the aftercooler exit temperature T _A and the air flow rate Q is proportional to the inlet temperature T (after-cooler outlet temperature T _A) and that the proportion and the saturated water vapor amount W _s, and saturated water vapor content W _s And drain discharge time interval T _int
Is inversely proportional, the reciprocal of the drain discharge time interval T _int is proportional to the air flow rate Q. Therefore, by calculating the reciprocal of the time interval T _int of the drain discharge start, the air flow rate Q can be easily calculated, and the air flow rate Q can be known without installing a load factor meter (flow meter). .

Therefore, in the present embodiment, the air flow rate Q is calculated by a process as shown in FIG. That is, the inlet temperature T of the refrigeration air dryer 50 is detected, and the drain discharge time interval T _int is calculated based on this. And
This calculated value is divided into two systems, one of which is sent to the solenoid valve 4 for discharging drain, and the other is sent to the flow rate calculating means 20. When the calculated value is sent to the flow rate calculating means 20, the flow rate calculating means 2
0 calculates the reciprocal of the calculated value to calculate the air flow rate Q,
The flow value Q is displayed on the load factor display 22.

As described above, the drain discharge controller 21 according to the third embodiment differs from the drain discharge controller 1 according to the first embodiment in that the flow rate calculating means 20 having a very simple configuration is added. Thereby, the air flow rate Q can be measured although it is simple. As described above, by simply measuring the air flow rate Q and displaying the load factor, the usage state can be grasped, and the maintenance management can be performed efficiently.

Finally, FIG. 11 shows a refrigeration air dryer according to the fourth embodiment. Refrigeration air dryer 30
Is a refrigeration air dryer using the drain discharge controller 1, and the description of the main part of the dryer and the configuration and operation of the drain discharge controller 1 is omitted because they are the same as those of the conventional example and the first embodiment. By manufacturing a refrigeration air dryer using the drain discharge controller 1 like the refrigeration air dryer 30, it is possible to appropriately discharge only the drain without air loss, and to manufacture a highly reliable refrigeration air dryer at low cost. Can be provided.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various applications are possible. For example, in the third and fourth embodiments,
Although an example using the drain discharge controller 1 according to the first embodiment has been illustrated, it is needless to say that a similar effect can be obtained by using the drain discharge controller 11 according to the second embodiment.

[0044]

According to the drain discharge controller of the present invention, a temperature detecting means for detecting the inlet temperature of the compressed air to the air dryer, and a drain control for controlling the operation of the drain discharger based on a detection signal from the temperature detecting means. Means, it is possible to properly drain only the drain,
It is possible to provide a drain discharge controller that performs highly reliable drain discharge without air loss. For this reason,
The service life of the drainer is prolonged, and maintenance is improved. Furthermore, by using a thermistor as the temperature detection means and a timer IC as the drain control means, a drain discharge controller that discharges only the drain appropriately and very simply and inexpensively and performs highly reliable drain without air loss is manufactured. It becomes possible to do. Further, by manufacturing a refrigeration air dryer using the drain discharge controller of the present invention, it is possible to appropriately discharge only the drain without air loss and to provide a highly reliable refrigeration air dryer at a low cost. Can be.

[Brief description of the drawings]

FIG. 1 is a system diagram of a drain discharge controller according to a first embodiment.

FIG. 2 is a block diagram showing control of a drain discharge controller according to the first embodiment.

FIG. 3 is an explanatory diagram for describing a process of S2 shown in FIG. 2;

FIG. 4 is a system diagram of a drain discharge controller according to a second embodiment.

FIG. 5 is a graph showing a relationship between a resistance value of a thermistor and a saturated water vapor with respect to an inlet temperature.

FIG. 6 is a system diagram of an air compressor and a refrigeration air dryer.

FIG. 7 is a graph showing a relationship between an inlet temperature and an air flow rate in the system shown in FIG. 6;

FIG. 8 is a system diagram of a drain discharge controller according to a third embodiment.

FIG. 9 is a graph showing a relationship between an air flow rate discharged from an air compressor and an outlet temperature.

FIG. 10 is a block diagram showing control of a drain discharge controller according to a third embodiment.

FIG. 11 is a schematic diagram of a refrigeration air dryer according to a fourth embodiment.

FIG. 12 is a schematic view of a conventional refrigeration air dryer.

FIG. 13 is a schematic view of a conventional mechanical drain discharger.

FIG. 14 is a system diagram showing the operation principle of a conventional solenoid valve type drain discharger.

FIG. 15 is a system diagram showing an operation principle of a conventional interval type drain discharger.

[Explanation of symbols]

 1, 11, 21 Drain discharge controller 2 Temperature sensor 3, 13 Drain control means 4 Solenoid valve 10 Photocoupler 12 NTC thermistor 14 Timer IC 20 Flow rate calculation means 22 Load factor display 30, 50 Refrigeration air dryer 51 Capacitor 52 Evaporator 53 Precooler 54 Drain discharger 55 Cooling device (fan) 56 Capillary tube 57 Compressor 59 Adjustment valve

Claims (5)

(57) [Claims] 1. A drain discharge controller of a refrigeration air dryer that removes moisture from compressed air and discharges the moisture from a drain discharger, wherein a temperature detection means for detecting an inlet temperature of the compressed air to the refrigeration air dryer. A drain control means for controlling operation of the drain discharger based on a detection signal from the temperature detection means. 2. A drain discharge controller for a refrigeration air dryer according to claim 1, wherein said drain control means changes a time interval of a drain discharge start of said drain discharge device in conjunction with said detection signal. Drain controller of the refrigeration air dryer that does. 3. A drain discharge controller for a refrigeration air dryer according to claim 2, wherein a thermistor is used as said temperature detecting means and a timer IC is used as said drain control means. 4. A drain load controller for a refrigeration air dryer according to claim 1, wherein a simple flow rate is calculated by calculating a reciprocal of a time interval of the start of drain discharge and calculating and displaying the simple flow rate. A drain discharge controller for a refrigeration air dryer having a rate meter. 5. A refrigeration air dryer for removing moisture from compressed air, the refrigeration air dryer having a drain discharge controller for the refrigeration air dryer according to any one of claims 1 to 4.