DE3031936A1 - METHOD FOR OPERATING A COOLING SYSTEM - Google Patents

Description

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The invention relates generally to a cooling system and to a method of operating a cooling system of the type which includes a multiple cylinder compressor or multiple compressors, in particular to a method for regulation the operation of a cooling system at ambient temperatures which exceed the system temperature.

When operating a cooling system, the temperature and pressure inside the condenser increase when the ambient temperature of the condenser and evaporator can be increased beyond specified limits. In the event of an increase, four ambient temperature Beyond the temperature range specified for the system, the high pressure side or the condenser pressure can reach the operating limits and cause the cooling system to be shut down. However, it is desirable to operate the refrigeration system to maintain and still provide a certain cooling during the time during which the ambient temperature exceeds the system temperature.

In known refrigeration systems with two or more compressors or two or more cylinders within one compressor, one has the capacity of the compressor is changed to keep pace with changes in load that occur when the refrigeration system is used Is subject to changes in the ambient temperature. It has proven desirable in known systems that Reduce the compressor capacity of the refrigeration system when the load on the system drops or increase the compressor capacity when

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the load on the system increases. In unusually hot weather, the load or cooling requirement of the cooling system increases. Around To meet this requirement, it was previously necessary to use a larger motor to operate the compressor or ei ^ To use multiple compressor system. Refrigeration systems with variable Capacity which has two or more compressors or a compressor with two or more cylinders in parallel have, are provided with devices for loading and unloading the cylinder to the capacity of the To change the system according to the cooling requirement. In these systems, the compressor is relieved, as is the cooling load drops, and the compressor is loaded as the cooling load increases. This can be done through a bypass connection the discharge side of the compressor with the suction side inside the compressor or by blocking the suction side to the compressor cylinder inside the compressor or by shutting off one or more of the multiple compressors. With a bypass capacity relief system Solenoid valves are generally arranged in bypass lines, which are located between the delivery lines of the individual compressor cylinders and the compressor suction line. By opening of the valve, part of the compressed gas flows directly from the delivery line to the suction line of the compressor without passing through to flow through the condenser or evaporator, which reduces the amount of refrigerant flow through the system and the Load of the compressor motor is limited. To increase the capacity

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speed of the compressor will be one or more. Valves in the bypass lines are closed. These systems are designed to operate within specified ambient temperature ranges designed.

The task of the ^1. ··: The invention consists in creating an improved operation of the cooling system when the ambient temperature rises above predetermined limits.

A special feature of the invention consists in the creation of control device «^; *, which as a function of an increase in function in the ambient temperature or the pressure on the high pressure side beyond specified limits step to the refrigeration system under high ambient temperature conditions keep in operation.

The cooling system according to the invention has simple, reliable, fully automatic means that allow the system to operate at ambient temperatures above a predetermined value to work.

These and other features and advantages of the invention are achieved by measuring the ambient temperature or the Coolant on the high pressure side and by relieving the compressor depending on a maximum ambient temperature or a high pressure side pressure, thereby increasing the coolant flow rate through the condenser and the pressure in the condenser is reduced. This enables the facility to operate at a relatively reduced rate

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Speed to work during periods of high ambient temperature.

Show it:

Fig. 1 is a schematic representation of a cooling system to explain an embodiment of the invention in which unloading of the compressor is provided by means that respond to the pressure on the high pressure side of the system,

Fig. 2 is a partially schematic representation of an optionally possible circuit in which the discharge the cooling system is provided by devices that respond to the ambient temperature,

Fig. 3 is a partial representation of an electrical circuit diagram showing the connection between a high pressure switch and shows relief devices for the refrigeration system including a number of rows of cylinders according to the invention

Reference is now made to the drawings. Fig. 1 shows the cooling system with a multi-cylinder compressor 10, which contains two cylinders 11 and 12. The cylinders and 12 point conveyor lines extending therefrom 13 and 14, respectively, which flow through the compressed gaseous

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Coolant from the compressor 10 to a condenser 15 allow.

It should be noted that the compressor 10 is not based on two cylinders is limited, but may include a number of cylinders connected to the capacitor 15 in the same way like aJ.e cylinders 11 and 12. A number of individual compressors can also take the place of the cylinders in the compressor 10.

The hot gaseous refrigerant from the compressor 10 is transferred to the condenser 15 is converted into a liquid by passing the gaseous refrigerant into a heat exchanger Relationship with the ambient air or any other cooling medium. The liquid coolant then flows through an evaporation device 16 to an evaporator 1.7. In the vaporizer the liquid coolant evaporates and absorbs heat from the medium to be cooled. The secondary vapors flow then to the compressor through a Saualeitunq 19. In the line 14, a check valve 18 is arranged to prevent the flow of the refrigerant from cylinder 12 through delivery line 14 into the condenser coil 15 to allow and to prevent the flow of refrigerant from the delivery line 13 into the line 14. In a Bypass line 22, which connects the delivery line 14 to the suction side of the compressor, a relief valve 20 is switched on. A conventional solenoid valve can be used as a relief

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valve 20 can be used. Generally, the valve's plunger closes the line when the solenoid of the Valve 20 is not energized and there is no conveying gas in line 14 in the bypass to the suction side of the compressor returned. Both compressor cylinders are running, and the Plant is in the state of working at full capacity. The solenoid coil of valve 20 can optionally pass through an electrical circuit 21 shown in Fig. 1 and a suitable relay switch 23 and an electrical power source 24 contains. The electrical circuit that energizes the vent valve can be part of the electrical circuit used for the entire refrigeration system. The switch 23 is on normally open electrical switch and with a high pressure control such as a pressure operated one Fan 25 connected. One end of the fan 25 is connected to the electrical contact of the switch 23 by a linkage. The opposite end of the fan 25 is connected to the delivery line 14 of the compressor by a line 26, which monitors the pressure supply line "K. An increase in the Pressure in the line 14 causes the fan 25 to expand, and this closes when a predetermined pressure is reached Blower the switch 23. The blower 25 is preset to close the switch at a maximum allowable pressure value on the high pressure side of the cooling system.

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Although the line is shown in connection with the delivery line 14 26, it can "but any point on the high pressure side are connected to the system for purposes of this invention, which is able to provide a source at high pressure cooling ^medium.:

When operating in increasing ambient temperatures an increase in the system's cooling load and a corresponding increase in condenser head pressure. Under conditions where the Ambient temperature exceeds a certain limit, the fan 25 reacts by closing the electrical contact of switch 23, thereby creating a closed electrical Circuit for the passage of electricity into the coil of the solenoid valve 20. The excitation of the coil of the solenoid valve moves the plunger body of the solenoid valve in one direction to open the bypass line 22. Through Opening the solenoid valve 20 flows em part of the hot promoted Gas from the delivery line 14 dunh the line 22 directly to the suction side of the compressor 10 without passing through the condenser 15, to pass through the expansion valve 16 and the evaporator 17, and thereby reduces the rate of refrigerant passing through the refrigeration system. This reduces the burden of the Compressor and condenser. When the secondary refrigerant flow increases the condenser is limited, then this lowers the pressure in the condenser. The lower pressure in the condenser allowed the cooling system continues to operate at reduced capacity, even if the ambient temperature is lower than that in the construction exceeds the specified limits of the overall system. It is

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It should be noted that the compressor is controlled by the delivery pressure switch 25 is relieved or switched off when the system approaches the maximum operating pressure. The differential This switch is far enough so that the reduction of the jerk, the relief or the disconnection of the ompressors is caused, the switch does not reset and the compressor starts again or is loaded. Between If there is a direct relationship between the outside temperature and the delivery pressure, a reduction in the outside temperature is necessary, before the switch resets itself and elastic or starts the compressor. At this reduced ambient temperature the unit works with the compressor fully loaded. The procedure described above to relieve the ompressors when the head pressure approaches the maximum permitted limit for the operation of the unit unit remains in the operating state with reduced capacity, but at a higher ambient temperature.

It should be noted that although the solenoid valve is arranged externally is shown in a bypass line in the preferred embodiment, the internal arrangement of the valve η of a bypass line from the delivery side to the suction side inside a compressor housing in the system can also be used.

ig. Fig. 2 shows a partial view of the circuit similar to that in ig. 1, in which a normally open switch

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23 to an ambient temperature control or a measuring device device 30 is connected. The compressor is unloaded depending on the ambient temperature, which is from the temperature control 30 is measured, which is set so that the switch contact 23 at a predetermined Maximum value of the ambient temperature schl: e: ß.

3 shows an electrical diagram to illustrate a connection between the electric switch 23 and the relief valve 20 in a case where a compressor with a number Rows of cylinders or a number of compressors Ir. the unit to Application. For example, Fig. 3 shows a four-cylinder compressor. As soon as the head pressure increases to the maximum permissible value for the operation of the unit, the electrical one closes Switch 23 and energizes the relief valves 20. The number of electrical switches and relief valve used would be dependent on the particular unit and intended use.

Various switches 23 can also be added in connection with other relief valves and bypass lines, a relieving effect on the compressors when the ambient temperature rises to create.

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While the invention in connection with a preferred embodiment form has been described, it is recognized that deviations and changes are possible without changing from that in the The invention as laid down in the claims.

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Claims (6)

.) Method for operating a refrigeration system with multiple compressors or a multi-cylinder compressor, characterized by the following steps: Operating the cooling system up to full capacity, measuring the conditions that indicate the load on the system, partially relieving the load of the compressor under measured conditions that indicate a system load above the normal operating load of operating the refrigeration system at reduced capacity until conditions are measured which indicate that the load the system has been reduced to the normal operating load. 130013/1252 APPROVED VEITTRKTKIT AT THE ETJKOPXlSCnEN PATENT OFFICE PROFESSIONAL HKI'BKSIiM.lTH UN 111! 1'ORKTIIiI ΕΙΓΚΟΓΕΑΝ PATENT OFFICE "">'' · "" «MtiK AQ, HiMOURn (DLr. 200 700 00) NK. 03/28407 -nuzs & NEK miiK χα, erudko (Ul. 7. Ζ00 800 00) Ml. 0Π3 00 33 TOSTSCnECK HMD. 2812-20 (1 303193g 2. A method for operating a cooling system according to claim 1, characterized by partially relieving the compressor including a diversion of the conveying gas from some of the cylinders or compressors directly to the suction line of the compressor. 3. A method for operating a cooling system according to claim 1 or 2, characterized in that a high pressure side in the delivery line of the compressor is measured and the compressor is relieved when the measured pressure on the high pressure side is normal Operating pressure exceeds. 4. A method for operating a cooling system according to claim 1 or 2, characterized in that an ambient temperature is measured and the compressor is unloaded when the measured ambient temperature exceeds the specified maximum temperature. 5. Gas compressor control, characterized by a bypass line (22), which connects the compressor delivery side with the compressor 'compressor inlet. Valve devices (20) in the bypass line (22) for controlling the flow of high pressure gas from the compressor delivery side to the compressor inlet, a electrical circuit (21) which is operatively connected to the valve devices for opening these valve devices (20) is, switching means (23) in the electrical circuit (21) for energizing and de-energizing the circuit to thereby ... 12 130013/1252 ORIGINAL BATHROOM - 303193! to control the operation of the valve device (20), as well as measuring devices for measuring the conditions associated with the Switching devices (2 3) are connected to close the switch depending on conditions when the ambient temperature exceeds a predetermined permitted limit for the system. 6. Cooling system with an evaporator, a multiple-cylinder compressor or multiple compressors, a condenser that is switched on in a closed circuit for the flowing refrigerant, control devices, characterized by a bypass line (22) which connects the delivery line (14) of a compressor cylinder (12) or compressor (10) connects to the suction line of the compressor (10), a solenoid valve (20) which is arranged in the bypass line (22) to open and close the bypass line, an electric one Circuit with a normally closed switch (23) which is electrically connected to the solenoid valve, a pressure valve (25) which connects to the delivery line of the compressor (10) and is effective in the delivery line (14) as a function of a predetermined head pressure, this pressure valve (14) being operatively connected to the electrical switch (23) in order to close the electrical circuit and the bypass line (22) to open the conveying gas from some of the cylinders (12) or compressors (10) to the suction line of the compressor (10) when the conveying line pressure exceeds the maximum operating pressure. 130013/1252 "* ^{/ 4}