JPH037854A - Freezer - Google Patents

Abstract

PURPOSE:To reduce a pressure variation within a device or a movement of liquid and to enable a stable refrigerant operation to be carried out by a method wherein a high pressure liquid receptacle container is provided with an upper stage liquid surface level sensor and a lower stage liquid surface level sensor, a main liquid solenoid valve is closed when the upper stage liquid surface level sensor is operated and the refrigerant liquid is pumped down to the high pressure liquid receptacle container. CONSTITUTION:As liquid surface levels in liquid receptacle containers 3a and 3b are lowered, upper stage liquid surface level switches 16a and 16b are operated to close main liquid solenoid valves 4a and 4b. At this time, compressors 1a and 1b keep their operations, so that the refrigerant passes through a low pressure receiver 10, a liquid pump 11, a solenoid valve 12 and a low pressure side of an air cooling device 13, compressors 1a and 1b and then is pumped down to condensers 2a, 2b or liquid receivers 3a and 3b. As the liquid surfaces are returned to their original levels and contact points of liquid level switches 16a and 16b are returned to their original states, main liquid solenoid valves 4a and 4b are opened for a specified period of time to continue a cooling operation. ln case that the liquid surface level is lowered even if the pumping-down is carried out, the lower stage liquid surface level switches 6a and 6b are operated to stop the operation of the compressor 1.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a refrigeration system, and particularly to a refrigeration system in which two units are operated in parallel. 2゜ This is related to refrigerant control during rotation.

[Conventional technology]

FIG. 2 is a refrigerant system diagram of a conventional refrigeration system.

In the figure, (1)-a is a compressor, (11-b is a two-tooth compressor, (2)-a is a Nhl condenser, and (2)-b is a compressor.
I&12 condenser, (3) -a is NQl receiver, (3)
-b is 2 liquid receivers, (4) -a is NQI main liquid solenoid valve, (41-b HapI & 12 main liquid solenoid valve, (5) -a
(5)-b is the pressure equalization piping between the condenser (2a) and the liquid receiver (3a) of tooth 1, and (5) -b is the pressure equalization pipe between the condenser (2b) and the liquid receiver (3a) of tooth 1.
3b) pressure equalization piping, (6)-a! ! 11 liquid receivers (3
a) The internal liquid level detection needle (6)-b is connected to the liquid receiver (3) of &2.
b) The internal liquid level detection needle (7) is Nhl, the pressure equalizing pipe (8) between the NhZ liquid receivers (3a) and (3b) is P&L1, No.
, the liquid equalizing pipe (9) between the two liquid receivers (3a) and (3b) is the main liquid pilot valve, QO is the low pressure liquid receiver, αυ is the refrigerant liquid pump, and (6)-a-b-c is the refrigerant liquid. Solenoid valve Q3-a-
b-c is air cooler, α is Nhl, ? Pressure equalization piping between 1 & 12 condensers (2a) (2b), α'J-a is a solenoid valve for Nhl injection, a! 9-b is a solenoid valve for Nh2 injection.

Next, the operation will be explained. When one compressor performs capacity control operation during refrigeration operation, the pressure inside the device fluctuates. The pressure balance collapses and the pressure in the system where capacity control is implemented becomes low. Therefore, pressure equalization piping from the unit operating at full load (
7) α (Refrigerant gas and liquid transfer through the liquid equalization pipe (8).

If rapid liquid movement occurs at this time, the liquid level in one of the liquid receivers will drop and the liquid level detector (6)-a or (6)
)-b operates and causes the compressor to stop abnormally.

[Problem to be solved by the invention]

Conventional refrigeration systems are configured as described above, so they suffer from pressure fluctuations and liquid transfer every time the compressor in one system is stopped during capacity control operation, resulting in a high frequency of abnormal liquid level alarms. This invention was made to solve the above-mentioned problems, and aims to provide a refrigeration system that can suppress fluctuations in liquid level and reduce the frequency of stopping the compressor due to an abnormality alarm. The purpose is

[Means to solve the problem]

The refrigeration system according to the present invention has two levels of liquid level detectors, and when the upper level level detector is activated, the main liquid solenoid valve is closed for a certain period of time while the compressor continues to operate. Furthermore, when the liquid level drops and the lower liquid level detector is activated, the compressor is stopped and an abnormality alarm is generated.

[For production]

The refrigeration system according to the present invention detects a drop in the liquid level using the upper liquid level detector, closes the main liquid solenoid valve, and performs pump-down operation, thereby suppressing the drop in the liquid level. Additionally, by stopping the compressor using the lower liquid level detector, the frequency of abnormality alarms is reduced.

[Embodiments of the invention]

Hereinafter, an embodiment of the present invention will be explained with reference to the drawings. This is the upper side of a liquid level detector with a built-in float (not shown). The upper part of this liquid level detector is
The pressure is equalized to the gas side of the NQl, tb2 liquid receivers (3a) (3b), and the lower part is Nhl, Nb2, liquid receivers (3a) (3b).
It is installed to equalize the liquid to the liquid side. The electrical contacts of the liquid level switch are connected to an electrical circuit that controls the opening and closing of the main liquid solenoid valve.

(6) -a, (6) -b lower liquid level switch is the same as first stage liquid level switch αe-a, Qθ-. Although it is piped, the operating point of the switch is installed at a lower position than the upper liquid level switches (16a) (16b).

Note that the other configurations are the same as those of the prior art, so explanations will be omitted. When the liquid level in the liquid receiver (3) ((3a) (3b) decreases, the upper liquid level switch ((16a) (1
6b)l operates and the main liquid solenoid valve (4) ((4a)(4
b) Close). At this time, the compressor (1) is ((1aXl
b))) continues to operate, so the refrigerant is supplied to the low-pressure receiver OQ, liquid pump αυ, solenoid valve (c), and air cooler α.
From the low pressure side of 3, pass through the compressor (1) f (la) (tb)) to the condenser (2) ((23X2b)) and receiver (3).
Pumped down to ((3a)(3b)).

The liquid level returns and the liquid level switch αυ((16a)(
When the contact point of 16b)) returns to its original state, after a certain period of time, the main liquid solenoid valve (4) I (4aX 4b) I is opened again to continue the cooling operation. Even if the pump down is performed, the liquid level further decreases and at t: the lower stage liquid level switch (6aH6b) is activated to stop the operation of the compressor (1).

In the above embodiment, the liquid level switch 7 was explained using a float type one, but an electrical one may be used as long as it can detect the liquid level.

〔Effect of the invention〕

As described above, according to the present invention 1, the high-pressure liquid receiver is equipped with upper and lower liquid level detectors, and when the upper liquid level detector is activated, the main liquid solenoid valve is closed for a certain period of time, and the refrigerant liquid is discharged. Since the refrigerant is configured to be pumped down to a high-pressure liquid receiver, stable refrigerant operation is possible by minimizing pressure fluctuations and liquid movement within the device.

[Brief explanation of the drawing]

FIG. 1 is a refrigerant system diagram showing a refrigeration system according to an embodiment of this invention, and FIG. 2 is a refrigerant system diagram showing a conventional refrigeration system. (1)-a in the figure is! ! 11 system refrigerant compressor, θ]) - tooth 2 system compressor, (21-a is positive 1 condenser, (21-
b is! 1 & 12 condensers, (3)-a is Arashi 1 high pressure receiver,
(3)-A is a positive 2-liquid high pressure liquid receiver, (4)-a is a 1-liquid solenoid valve, (4)-b is a 2-liquid positive solenoid valve, (5) -a is a 2-liquid electromagnetic valve? !
11 condenser and high pressure liquid receiver, (s) -b is the pressure equalization pipe of the Nci2 condenser and liquid receiver, (61-a is the lower liquid level detector of positive 1, (6 )-b is the lower liquid level detector of Oni 2, (7) is the per-pressure liquid receiver pressure equalization piping for tooth l and Nn2, (8) is the high pressure liquid receiver liquid equalization piping for NQI and Nn2, (9) is the main liquid pilot valve oQ is the low pressure receiver, 0
υ is the refrigerant liquid pump, (2) is the refrigerant liquid solenoid valve αJ is the air cooler, α5-a, &l liquid injection solenoid valve,
05-b is a solenoid valve for tooth 2 liquid injector 1, αG-a
Hanagi 1 upper level liquid level detector, αe-b is P! 12 Upper liquid level is an indicator. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] Two sets of refrigerators each consisting of a compressor, a condenser, a high-pressure liquid receiver, and a solenoid valve are connected with a pressure equalizing pipe between each set of condensers, and between the high-pressure liquid receivers with a pressure equalizing pipe and a liquid equalizing pipe. In a refrigeration system in which the high-pressure receiver is equipped with a lower liquid level detector, the high-pressure receiver is further provided with an upper liquid level detector, and the upper liquid level detector is The operation closes the main liquid solenoid valve while continuing the operation of the compressor, and after the contact of the upper liquid level detector returns, the main liquid solenoid valve is opened after a predetermined period of time, and the main liquid solenoid valve closes, and the lower liquid level detector A refrigeration system characterized in that the compressor is stopped by the operation of the refrigeration system.