JPH0261376A - Refrigerator - Google Patents

Abstract

PURPOSE:To uniformalize the oil surface height of each compressor by connecting one compressor chamber and the intakes pipe of the other compressor through a pipe in which a solenoid valve is installed midway, in a refrigerator in which a plurality of compressors are connected in parallel to a coolant circuit. CONSTITUTION:Compressors 1a and 1b are arranged in parallel on an installation frame 3 installed on a condenser 2, and discharge pipes 4a and 4b and intake pipes 5a and 5b are connected in parallel with the compressors 1a and 1b. In this case, each one edge of the oil levelling pipes 6a and 6b consisting of the pipes having a small diameter having a proper resistance is connected at the height position of the proper oil level in the chamber of each compressor 1a, 1b, and solenoid valves 7a and 7b are installed midway in the oil levelling pipes 6a and 6b. Further, the other edge of each oil levelling pipe 6a, 6b is connected to the intake pipe 5a, 5b of the other compressor 1b, 1a. Then, the imbalance of the oil quantity in each compressor 1a, 1b is eliminated by alternately opening each solenoid valve 7a, 7b in a certain time interval.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the control of a refrigeration system in which a plurality of high-pressure chamber one-type compressors are operated in parallel, and in particular, the present invention relates to the control of a refrigeration system in which a plurality of high-pressure chamber single-type compressors are operated in parallel. The present invention relates to a refrigeration system suitable for equalizing .

[Conventional technology]

Conventional equipment mainly relates to refrigeration equipment using a low-pressure chamber one-type compressor, such as Utility Model Application Publication No. 59-156190 and TFI Application Nos. 57-131883 to 131886, and high-pressure chamber one-type compressors. There is no discussion regarding an oil equalization device for a parallel type refrigeration system equipped with a compressor.

[Problem to be solved by the invention]

When operating multiple compressors in parallel, the amount of lubricating oil in each compressor may change over time due to differences in the amount of oil coming up from each compressor and the amount of oil returned from the cycle, and differences in the amount of distribution in the suction piping. This will cause an imbalance and cause burnout of the compressor. As a solution to this problem, in conventional refrigeration equipment equipped with a single-type low-pressure chamber compressor, the compressor chambers are connected to each other with oil equalizing pipes, and one of the compressors is forcibly stopped, or the suction pipe shape is The internal pressure in the chamber of each compressor was changed based on the difference in gas resistance, and the lubricating oil of each compressor was appropriately moved through an oil equalizing pipe to balance the oil level. However, in a refrigeration system equipped with a compressor that employs a single high-pressure chamber, the chamber is in a high-pressure region, so changes in operating conditions or resistance differences due to the shape of the suction pipe will cause a reliable pressure difference between each chamber. Adding is 1All! Therefore, it is impossible to reliably control the movement of oil using oil equalizing pipes connecting each chamber as in the past, and there is a problem in maintaining oil equalization between each compressor.

An object of the present invention is to improve the oil equalization system of a refrigeration system incorporating a parallel compressor that employs a single high-pressure chamber type.

[Means to solve the problem]

The above purpose is to connect the upper part of the oil level in the chamber of one compressor and the suction pipe of the other compressor to each other with a pipe that has an appropriate resistance and a solenoid valve installed in the middle, and periodically By alternately connecting + to the magnetic valve, an oil imbalance occurs, and if there is a compressor with more oil than required in the chamber, the excess oil will be transferred to the suction side of the other compressor. This is achieved by reducing the pressure and returning it.

[Effect]

A lubricating oil outlet is provided in the chamber of each compressor at the top of the required oil level, and from there to the suction pipe of the other compressor, a solenoid valve is installed in the middle of the pipe that waits for an appropriate resistance. each connected. During normal operation, the solenoid valve is closed, so there is no movement of oil. While the compressor is operating, each solenoid valve is periodically and alternately opened for a certain period of time. When one of the solenoid valves is circuited, the pressure inside the compressor chamber/bar is high, so oil or refrigerant is introduced into the suction pipe of the other compressor due to the differential pressure. Due to the above-mentioned action, if oil has accumulated above the lubricating oil outlet, only that amount of oil will be moved to the other compressor, but the oil at the outlet will not be moved. By repeating this operation regularly and alternately, the oil balance of each compressor can be improved. In addition, since the oil supply piping is equipped with an appropriate resistance, it is possible to control the amount of oil movement, preventing the negative effects of compressor oil suction, and to minimize the movement of refrigerant gas. By adjusting the resistance and oil equalization time, problems such as performance deterioration and overheating operation can be minimized and operation can be performed in a good oil equalization state.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 shows an example of a structural diagram of a refrigeration system according to an embodiment of the present invention. FIG. 2 is a circuit diagram of the compressor operation control device.

The compressors la and 1b are installed side by side on the mounting frame 3 provided on the condenser 2, and the discharge pipes 4as4bs
A suction pipe 5a I 5b and an oil equalizing pipe 6 are connected to each compressor in parallel. Further, the oil equalizing pipes 6a16b connected to the chambers of the compressors la and lb are each constructed of a thin pipe having an appropriate resistance, and electromagnetic valves 7a and 7b are provided in the middle. Further, the connection port is connected to the other suction pipe 5a+5b at a position of the appropriate oil level of each compressor 1allb. Moreover, the solenoid valves 7a and 7b are as shown in the control circuit of FIG.
The timer 8a and e8b for time-limited operation and time-limited return are set to repeat the operation of closing and opening 1 for, for example, 60 minutes, and the operations of the two timers are set to be delayed, for example, by 30 minutes. As a result, each solenoid valve 7a I 7b is activated alternately and periodically for a short period of time.
Repeat the opening action.

In the above structure and control, if an oil volume imbalance occurs between the two compressors 1a+1b, for example, the oil level of the compressor la is higher than the connection port of the oil equalizing pipe 7a, and the oil level of the other compressor 1b is If the oil level is low, solenoid valve 7
When a opens, the oil above the connection port of the oil equalizing pipe 6a is depressurized by the resistance of the oil equalizing pipe f6a, and is introduced into the suction pipe 5b little by little at a differential pressure, where it is compressed together with the suction gas. Machine 1bK is inhaled.

In addition, the solenoid valve 7a is opened and at the 9th point, the oil level level is increased to the oil leveling pipe 7a.
If it is lower than the connection port, oil movement will not occur. By periodically performing such operations alternately, each compressor replenishes oil with the other, so that even if either compressor runs out of oil, a constant amount of oil can always be ensured.

〔Effect of the invention〕

According to the present invention, even if an unbalance in the oil amount of each compressor occurs due to parallel operation of multiple compressors employing a single high pressure chamber type in one cycle, each compressor is periodically and alternately operated. Since oil in excess of the amount required for the machine is supplied to other compressors by differential pressure, a certain amount of oil can always be secured.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of a refrigeration system according to an embodiment of the present invention, and FIG. 2 is a control circuit diagram thereof.

Claims (1)

[Claims] In a refrigeration system in which multiple compressors that maintain a high pressure atmosphere inside the chamber are connected in parallel to a refrigerant circuit, the upper end of the oil level of one compressor chamber and the suction pipe of the other compressor are connected to each other. The oil level in each compressor is made uniform by connecting the pipes with a certain appropriate resistance and having a solenoid valve installed in the middle, and opening the solenoid valves alternately at regular intervals. refrigeration equipment.