KR910000680B1 - Refrigeration system purge control - Google Patents

Abstract

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Description

Refrigeration system and operation method

1 is a schematic diagram of a refrigeration system with a purifier operated in accordance with the principles of the present invention.

2 is a schematic representation of a control system for operating the purge apparatus shown in FIG. 1 in accordance with the principles of the present invention.

* Explanation of symbols for main parts of the drawings

1,2: 1st, 2nd temperature sensor 14: Evaporator

15: purification chamber 21: condensation coil

29 electric motor 32 solenoid valve

55: triac switch 56,57: optical coupling circuit

The present invention relates to a refrigeration system, and more particularly to a purifier for removing non-condensable gas and other contaminants from the refrigeration system.

Various refractory gases and other contaminants in refrigeration systems tend to mix with the refrigerant typically used in refrigeration systems and to aggregate at some point on the top of the condenser in the refrigeration system. The presence of non-condensable gases and other contaminants in the refrigeration system reduces the efficiency of the refrigeration system, for example, because it requires a higher condenser pressure and therefore relatively cold cooling water used to condense the refrigerant in the condenser. This is because the amount of cooling fluid or the power cost is increased. In addition, the capacity of the refrigeration system is reduced because the non-condensable gas discharges refrigerant vapor flowing through the refrigeration system.

To overcome the above-mentioned determination, various types of purifiers are used to raise or purge non-condensable gas and other contaminants from refrigeration systems. Such a purifier includes a purge chamber for collecting and discharging non-condensable gas such as air to the atmosphere. The gas collected in the clarification chamber also contains water vapor and some refrigerant vapor. Typically, the heat transfer coil is located in the purification chamber and is supplied with cooling oil such as water or refrigerant. The heat transfer coil serves as a condensation coil for condensing refrigerant and water vapor into a liquid in the purification chamber. After that, condensed liquid components such as refrigerant and water are removed from the purge chamber.

Typically, the condensed liquid refrigerant is recycled to the refrigeration system and the condensed water is discharged from the refrigeration system. Non-condensable gas is usually discharged to the atmosphere by an automatic pump that operates in response to pressure variations between the condenser and the purification chamber of the refrigeration system.

In the purifier of the type described above, a differential pressure switch is usually used as a purge safety switch for detecting the pressure difference between the refrigerant in the condenser of the refrigeration system of the refrigerant in the evaporator. If the purge safety switch detects that the refrigerant pressure difference between the evaporator and the condenser is less than the undesirable value for the purifier operation, the purge safety switch is opened to stop the purifier operation. In this way, the purge safety switch stops the purge operation when it is undesirable for the purifier to operate, such as when the refrigeration system is stopped and when the refrigerant pressure in the evaporator is approximately equal to the refrigerant pressure in the condenser.

The differential pressure switch used as the purification safety switch in the above-described method is suitable for use and satisfies many of the purification control systems used in the refrigeration system. However, these differential pressure switches have some inherent drawbacks. For example, the disadvantage is that it is not suitable for use with an electronic control system because a transducer is necessary to convert the pressure signal into an electrical signal suitable for the electronic control system. In addition, these differential pressure switches are prone to mechanical wear and tear and have a relatively high cost.

It is therefore an object of the present invention to provide a refrigeration system having a purification device having a purification safety switch suitable for an electronic control system for a refrigeration system.

Another object of the present invention is to improve the reliability and reduce the cost of the purification apparatus used to remove non-condensable gas and other contaminants from the refrigeration system.

It is yet another object of the present invention to purify the electrical signal indicative of the detected operating state so that it is not necessary to electrically detect an undesirable operating state for operating the purifier in the refrigeration system and convert the mechanical signal into an electrical signal. Supply directly to the control system of the device.

The above object and other general objects of the present invention are achieved by a control system and control method for a refrigeration system in which the electronic temperature sensor is electronically controlled so that the electronic temperature sensor provides a purification safety switch function without using a differential pressure switch. do. According to the invention, a first temperature sensor is arranged in an evaporator of a refrigeration system to provide a first electrical signal indicative of the refrigerant temperature in the evaporator. In addition, a second temperature sensor is disposed within the condenser of the refrigeration system to provide a second electrical signal indicative of the temperature of the refrigerant in the condenser. The first and second electrical signals are sensed by an electronic control device such as a microcomputer control system to process the first and second electrical signals according to a pre-programmed process to compare the temperature of the refrigerant in the evaporator with the temperature of the refrigerant in the condenser. Determine the temperature difference. The electronic controller generates a control signal when the monitored refrigerant temperature difference becomes below a predetermined value which is undesirable for operating the purifier. A switch device electrically connected to the electronic controller stops the operation of the purifier in response to the generation of the control signal by the electronic controller.

Other objects and advantages of the present invention will become apparent from the following detailed description of embodiments with reference to the accompanying drawings, in which like reference numerals designate like parts.

Referring to FIG. 1, there is shown a schematic diagram of a refrigeration system with a purifier operated in accordance with the principles of the present invention.

The refrigeration system shown in FIG. 1 is a conventional vapor compression refrigeration system in which refrigerant is compressed by a compressor (not shown) and discharged into the condenser 10.

The condenser 10 discharges the condensed liquid refrigerant to an expansion device 12, such as a poppet valve or a float valve or a simple orifice, which is refrigerated through a conduit 13. Liquid and geometric refrigerant are supplied to the evaporator 14 of the system. The liquid refrigerant in the evaporator 14 is geometrically cooled to cool a heat transfer fluid, such as water, flowing through the heat transfer piping (not shown) in the evaporator 14. The cold evaporated from the evaporator 14 is discharged through the discharge tube (not shown) to the suction side of the compressor to start another refrigeration cycle.

Various non-condensable gases and other contaminants are typically mixed with refrigerant in the refrigeration system and accumulate in the condenser 10. It is necessary to separate non-condensable gas and other contaminants from the refrigerant in order to purify the refrigeration system without losing the refrigerant. Purification chamber 15 is provided for this purpose. Purification chamber 15 is connected to lower condenser 10 by conduit 16 to extract the gas mixture from condenser 10 and transport it to purification chamber 15. This gas mixture entering the clarification chamber 15 will typically be a mixture of non-condensable gas, refrigerant vapor and water vapor.

The conduit 16 includes a strainer 17 for removing any particulate matter contained in the gaseous mixture from the condenser and an orifice 18 for controlling vapor flow between the condenser 10 and the purge chamber 15. Equipped. The conduit 16 also has an open valve 19 that is manually operated to isolate the purifier from the refrigeration system when the refrigeration system is pressurized through the leak check valve 20 of the refrigeration system and under good circumstances. The valve 20 is closed during normal purifier and refrigeration system operation.

The condensation coil 21 is disposed above the purification chamber 15 to receive low temperature fluid used to condense the refrigerant vapor in the purification chamber 15. The condensation coil 21 receives the low temperature fluid from the condenser 10 of the refrigeration system. The orifice 22 is provided in the inlet conduit to the condensation coil 21 to reduce the refrigerant pressure when the liquid refrigerant is supplied from the condenser 10 to the condensation coil 21 as shown in FIG.

A filter 23 is also provided to remove particulate matter that may be present in the refrigerant flowing from the condenser 10 to the condensation coil 21. The refrigerant discharged from the condensation coil 21 is returned to the evaporator 14 through the refrigerant outlet conduit 24.

The low temperature fluid circulating through the condensation coil 21 in the purification chamber 15 lowers the temperature of the refrigerant, non-condensable gas, and other contaminants accumulated in the purification chamber 15 to prevent non-condensable gas such as refrigerant vapor and water vapor. Will be condensed. Small dense condensate, such as water, accumulates as a layer on top of the relatively pure liquid refrigerant condensed in the purification chamber 15. The purification chamber 15 is provided with a float valve 25 for adjusting the oil level of the liquid refrigerant in the purification chamber 15. When the oil level rises in the purification chamber 15, the float valve 25 automatically discharges the pure liquid refrigerant from the purification chamber 15 to the evaporator 14 via the conduit 36 automatically, and the purification chamber 15 The float valve 25 is closed when the oil level in the cylinder falls below a predetermined oil level. An intermediate chamber 76 is provided to separate condensate from the condensation refrigerant.

The liquid refrigerant from the intermediate chamber 26 passes through the lower portion of the purification chamber 15 in which the float valve 25 is disposed. Water, which is a liquid having a lower density than the refrigerant, is located above the intermediate chamber 26. The axial wall of the intermediate chamber 26 is provided with a glass wall to visually observe the water surface. In addition, a manual valve 28 is provided on the shaft wall of the intermediate chamber 26 to drain the collected water.

Non-condensable gas such as air is integrated in the upper part of the purification chamber 15. As the non-condensable gas accumulates, the pressure in the purification chamber 15 rises to approach the pressure in the condenser 10. In order to extract the non-condensable gas, a purge pump 50 driven by the electric motor 29 is connected to the purge chamber 15 by a conduit 30. The conduit 30 includes a solenoid valve 32 with a solenoid coil 33 and a check valve 31 for controlling the flow of non-condensable gas to the purge pump 50.

As shown in FIG. 1, the purification apparatus has a normally closed purification operation switch 34, which is a differential pressure switch responsive to the pressure difference between the purification chamber 15 and the condenser 10. As shown in FIG. The purifier also includes a first temperature sensor 1 for sensing the temperature of the refrigerant in the evaporator 14 and outputting an electrical signal indicative of the detected temperature to the electrical output leads 3, 4. The purifier also has a second temperature sensor 2 for sensing the temperature of the refrigerant in the condenser 10 and outputting an electrical signal indicative of the sensed temperature to the electrical output lead lines 5, 5. Preferably, each of the temperature sensors 1, 2 is a temperature response resistor such as a thermistor.

However, as apparent by the valence of ordinary skill in the art to which the present invention pertains, each temperature sensor 1, 2 detects a refrigerant temperature and outputs an electrical signal indicating the sensed temperature. It is one of many different types of temperature sensors suitable for.

Referring to FIG. 2, a control system for operating the purifier shown in FIG. 1 in accordance with the principles of the present invention is shown. An operating switch 44 is provided to switch the control system between manual, stop and automatic modes of operation.

Power is supplied to the control system via wires 40 and 41 which are connected to an alternating current (not shown) of 115 volts, 50 or 60 hertz. Power is supplied from the power supply via a transformer 42 to a processor board 43 having a microcomputer, such as a model 8031 microcomputer produced from Intel Corporation, which has a business in Santa Clara, California. The processor board 43 is connected to the system interface board 47 through an interconnector 46 such as a ribbon cable. Power is supplied from the wire 40 to the system interface board 47 directly through the wire 52.

The system interface board 47 is preferably a triac swith, which is at least one switching device, such as the Model SCC-140, produced from CTIS Inc., which has a business in Skyland, North Carolina. 55 is provided. The triac switch 55 on the system interface board 47 is electrically connected to control the supply of power from the wire 52 to the relay 48. The triac switch 55 is opened and closed in response to an electrical signal supplied from the optical coupling circuit 57 on the system interface board 47 to the gate G of the triac switch 55. The optical coupling circuit 57 is controlled by a control signal supplied via an interconnector 46 from the processor board 43 to the optical coupling circuit 57 on the system interface face board 47. The optical coupling circuit 57 is provided to insulate the processor board 43 from the 115-volt power supply while allowing the processor board 43 to control the triac switch 55.

The processor board 43 is also directly connected through the output lead wires 3 and 4 to detect the electrical signal output by the temperature sensor 1 and is output to detect the electrical signal output by the temperature sensor 2. It is directly connected via the lead wire 5.6. In this manner, the processor board 43 detects the refrigerant temperature in the evaporator 14 and the refrigerant temperature in the condenser 10.

As shown in FIG. 2, the purge operation switch 34 is connected to the system interface board 47 in series. The optical coupling circuit 56 on the system interface board 47 is connected to the ribbon connector 46 when the switch 34 is closed to supply 115 volts of voltage from the wire 40 to the system interface board 47 through the wire 53. It is electrically connected to supply an output signal to the processor board 43 through. The main purpose of the optical coupling circuit 56 together with the optical coupling circuit 57 is to isolate the processor board 43 from the 115 volt power source connected to the wire 40.41. In this regard, each circuit 56, 57 may be an optically isolated triac trigger circuit or a suitable circuit as would be apparent to one of ordinary skill in the art to which this invention belongs.

In addition, as shown in FIG. 2, the solenoid coil 33 of the solenoid valve 32 is electrically connected in parallel with the purge pump motor 29, and the purge pump motor 29 and the solenoid coil 33 are relayed. It is electrically connected to a normally open relay contact 49 which is controlled by the operation of 48. The normally open relay contact 49 and actuation switch 44 are electrically connected in parallel as shown in FIG. The solenoid system 51 is electrically connected in series with the solenoid coil 33. The solenoid switch 51 is electrically connected in series with the solenoid coil 33. The solenoid switch 51 remains closed during normal automatic operation of the purifier. The solenoid system 51 is used only for manual control of the solenoid coil 33 in the same situation as the initial operation of the refrigeration system or the maintenance or inspection of the purifier and the refrigeration system.

When the operation switch 44 is switched to the manual operation mode during operation, power is supplied to the purge pump motor 29 to continuously operate the purge pump 50 regardless of other elements of the control system. This mode of operation is only desirable in certain specific situations, such as initiating an initial operation of the refrigeration system or when servicing or checking the purifier and refrigeration system.

When the actuation switch 44 is switcing to the stop mode of operation, the power is completely disconnected from the control system to stop the control system. This mode of operation is desirable only under certain specific circumstances, such as initiating an initial operation of the refrigeration system or during maintenance or inspection of the purifier and refrigeration system.

When the operation switch 44 is switched to the automatic operation mode, the control system performs the automatic control operation of the purification device. This is the normal mode of operation when the refrigeration system is operating under normal conditions. In such an operation mode, power is supplied from the power source to the processor board 43 through the wires 47 and 41 and the transformer 42 to operate the processor board 43. In addition, power may be supplied from the power supply to the system interface board 47 through the wire 52.

Electric power may also be supplied to the purge operation switch 34 via the wire 53.

In the automatic operation mode, the purge operation switch 34 is normally closed at the start of operation of the refrigeration system because there is no pressure punch in the refrigeration system necessary to change the position of the operation switch 34. However, a pressure deviation is generated shortly after the start of operation, and the purge operation switch 34 is opened. Typically, power is not supplied to the optical coupling circuit 56 on the system interface board 47 through the electric wire 53. Thus, no output signal is supplied from the system interface board 47 to the processor board 43, and in response, the processor board 43 keeps the triac switch 55 of the system interface board 47 open. And the relay 48 is inoperative to cause the associated relay contact 49 to open. When the relay contact 49 is opened, the solenoid coil 33 and the purge pump motor 29 are also stopped to stop the operation of the purifier.

Further, at the start of operation of the refrigeration system in the automatic operation mode, the processor board 43 determines the temperature difference between the refrigerant in the evaporator 14 and the refrigerant in the condenser 10 according to a predetermined programmed process. 2 processes electrical signals supplied from the processor board 43 to the processor board 43. If the temperature difference is less than a predetermined value causing a safety problem, it is not preferable to operate the stop device, and the processor board 43 is transmitted to the optical coupling circuit 57 on the system interface board 47 through the interconnector 46. Generates a control signal, and the electrical signal is supplied to the gate G of the triac switch 55 on the system interface board 47 to open the system 55, thereby causing the relay 48 to become inoperative. After that, the relay contact 49 is opened to stop the operation of the solenoid coil 33 and the purge pump motor 29. In this way, the operation of the purification system is stopped when the difference in refrigerant temperature between the evaporator 14 and the condenser 10 is below a predetermined value which is undesirable for the operation of the purification device as a safety issue. Thus, such mechanisms perform a purification safety switch function for the purification device.

However, when the condenser 10 and the evaporator 14 reach the normal operating temperature and pressure, a sufficient refrigerant temperature difference is generated between them, allowing the process board 43 to operate the refrigeration system through the temperature sensors 1 and 2. Will be detected. In addition, after sufficient time of operation, considerable non-condensable gas accumulates in the purifying chamber 15 to reduce the pressure deviation between the purifying chamber 15 and the condenser 10 to actuate the purifying operation switch 34. When the purge operation switch 34 is closed under this condition, the processor board 43 generates a control signal to cause the triac switch 55 on the system interface board 47 to be closed. In this way the relay 48 is actuated to cause the associated relay contact 49 to be closed. Thus, electric power is supplied to the purge pump motor 29 and the solenoid coil 33 of the solenoid valve 32 so that the non-condensable gas is pumped to the atmosphere outside the purge chamber 15 by the purge pump 50. The pressure of (15) is lowered.

When the pressure in the purge chamber 15 drops to a level sufficient to open the purge operation switch 34 by the purge pump 50, the processor board 43 moves the triac switch 55 on the system interface board 47. Generate a control signal to open.

In this way, the relay 45 becomes inoperative so that the associated relay contact 49 is opened so that the solenoid valve 32 is closed and the purge pump motor 29 is stopped. The series of operations is repeated so that each time a non-condensable gas is accumulated in the purification chamber 15 considerably so that the purification operation initial position 34 is closed.

During operation of the refrigeration system, the processor board 43 continuously detects the temperature difference of the refrigerant between the condenser 10 and the evaporator 14 through the temperature sensors 1 and 2, and when the temperature difference is less than a predetermined level, the triac switch ( 55 is opened to stop the operation of the purification pump (50). This characteristic stops the operation of the purifier when it is not desired, such as when the refrigeration system is stopped. This feature also eliminates the possibility of the purifier running continuously when the refrigeration system is operated at low lift.

Of course, the foregoing embodiments illustrate one specific embodiment of the invention, but various modifications and other embodiments will become apparent to those skilled in the art to which the invention pertains. Therefore, while the invention has been described in connection with specific embodiments, it can be variously modified and modified without departing from the scope of the invention.

Claims (7)

A refrigeration system having an evaporator 14 and a condenser 10 and a purifying device for removing a non-condensable gas; A first temperature sensor (1) for detecting a refrigerant temperature of the evaporator (14) in the refrigeration system and supplying a first electric signal indicating the detected temperature; A second temperature sensor (2) for sensing a refrigerant temperature of the refrigeration system condenser (10) and supplying a second electric signal indicating the sensed temperature; Receives the first and second electrical signals supplied by the first and second temperature sensors (1, 2), and processes the received first and second electrical signals according to a predetermined programmed process to the evaporator ( An electrical control system for determining a temperature difference between the refrigerant temperature of 14) and the refrigerant temperature of the condenser 10 and generating a control signal when the determined temperature difference is less than a predetermined value; And a system device connected to said control system for stopping operation of said purifier in response to a control signal generated by said control system. 2. A refrigeration system according to claim 1, wherein said first temperature sensor (1) comprises a temperature response resistor located in an evaporator (14) of a refrigeration system. 2. A refrigeration system according to claim 1, wherein said second temperature sensor (2) comprises a temperature response resistor located in a condenser (10) of a refrigeration system. The refrigeration system of claim 1 wherein the electrical control system comprises a microcomputer control system. 2. The system of claim 1, wherein the system apparatus comprises: a power source for supplying electric power to the motor 29 to operate the purge pump 50 in the purifier; A purge operation switch positioned between the power supply and the purge pump motor 29 and opened in response to a control signal generated by the control system to prevent power from flowing from the power supply to the purge pump motor to stop the operation of the purifier; A refrigeration system, characterized in that consisting of 34). A method for operating a refrigeration system having an evaporator 14, a condenser 10, and a purifier for removing non-condensable gas, the method comprising: detecting a temperature of a refrigerant of an evaporator 14 in a refrigeration system to detect the detected temperature. Supplying an indicating first electrical signal; Sensing a refrigerant temperature of a condenser (10) in a refrigeration system and supplying a second electric signal indicating the sensed temperature; Comparing the first electrical signal with the second electrical signal to determine a temperature difference between the temperature of the refrigerant in the evaporator 14 and the cold temperature in the condenser 10; And a step of stopping the operation of the purifier when the temperature value between the refrigerant in the condenser (10) of the refrigerant in the evaporator (14) is less than or equal to a predetermined value as a result of the comparison. 7. The flow of electric power from the power source to the purifier according to claim 6, wherein the battery step is performed when the temperature difference between the refrigerant in the evaporator 14 and the refrigerant in the condenser 10 is less than a predetermined value as a result of the comparison step. Refrigeration system operating method comprising the step of blocking.

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