JPS62200153A - Refrigerant level controller for refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a refrigerant liquid level control device for a refrigerator, and particularly for a refrigerator suitable for controlling the refrigerant liquid level in an evaporator of a centrifugal refrigerator, for example. This invention relates to a refrigerant level control device.

[Conventional technology]

Conventional 1 For example, in the refrigeration cycle of a centrifugal chiller, the amount of refrigerant flowing into the evaporator in response to load fluctuations is adjusted by determining the amount of refrigerant flowing into the evaporator according to the chilled water inlet temperature and installing a control in the refrigerant pipe. This was done by adjusting the opening of the valve. (Special Publication No. f@56-48778) [Problems to be Solved by the Invention] The above-mentioned conventional technology does not take into account the decrease in the heat transfer rate of the evaporator due to the decrease in the amount of refrigerant evaporation during load fluctuations. Ta.

In other words, when the load fluctuates, especially when the load is low, the amount of evaporation of the refrigerant decreases, and the refrigerant liquid level in the steady state increases.
In this case, the heat exchanger tubes in the upper part of the evaporator become difficult to tie, and heat exchange is not performed, so the heat transfer rate decreases and the evaporator cannot cope with the load unless the temperature of the evaporator is lowered. Lowering the temperature of the evaporator increases the head of the compressor, which increases the input power of the electric motor, leading to a decrease in the efficiency of the refrigerator.

On the other hand, as the load increases, the amount of refrigerant evaporation increases.

The refrigerant liquid level in the evaporator rises, but if the liquid level rises too much, mist mixes into the low-temperature refrigerant gas returning from the evaporator to the compressor. A so-called mist-up phenomenon is likely to occur.

Therefore, the present invention was made to solve the above-mentioned problems of the prior art, and by keeping the refrigerant level in the evaporator at an optimum level in accordance with load fluctuations, the heat passing through the evaporator during low loads is improved. It is an object of the present invention to provide a refrigerant liquid level control device for a refrigerator that can improve the efficiency of the refrigerator by preventing a decrease in the cooling rate and preventing mist-up due to an excessive rise in the refrigerant liquid level during high loads.

[Failure to solve the problem]

In order to solve the above-mentioned problems of the prior art, a refrigerant liquid level control device for a refrigerator according to the present invention has a configuration including a compressor, a compressor, a pressure reducing means, an evaporator, and a refrigerant connecting these. A liquid level detection means for detecting a refrigerant liquid level in which a heat transfer tube of the evaporator is immersed in the evaporator of the refrigerator equipped with piping and outputting a signal, and a liquid level for indicating an optimum refrigerant liquid level according to the load. and a liquid level control means for comparing the output signal of the liquid level detecting means with the liquid level indicated by the liquid level indicating means and adjusting the opening degree of the refrigerant pipe on the evaporator inlet side. .

The liquid level of the evaporator is controlled to the optimum liquid level in accordance with load fluctuations on the refrigerator.

[Effect]

Next, the operation of the refrigerant liquid level control device for a refrigerator having the above-mentioned configuration will be explained in accordance with the idea developed by the present invention.

When the load changes in the refrigeration cycle of the refrigerator, especially at low loads, the amount of refrigerant evaporation decreases as mentioned above, and when the refrigerant liquid level in the evaporator is at a steady state level, the upper heat transfer tube becomes difficult to wet. For.

The heat transfer performance of the evaporator is reduced. Therefore, it is thought that if the liquid level of the refrigerant liquid in the evaporator is controlled to a position where the upper heat transfer tube is wetted, the heat transfer rate will not decrease.

Therefore, in response to load fluctuations, a liquid level indicating means for instructing a reference liquid level to raise the refrigerant liquid level in the evaporator when the load is low and lower the refrigerant liquid level in the evaporator when the load is high, and a liquid level detecting means. Compare the liquid level detected by
By activating the tL surface control means and adjusting the opening degree of the S1j# valve in the refrigerant pipe on the evaporator inlet side, the refrigerant liquid level in the evaporator approaches the standard liquid level, that is, the appropriate liquid level. .

[Embodiments] . . . ζ. Each embodiment of the present invention will be described below with reference to FIGS. 11 and 2.

First, FIG. 1<a) is a block diagram of a centrifugal chiller equipped with a refrigerant level control device according to an embodiment of the present invention.

FIG. 1(b) is a schematic cross-sectional view of the evaporator section.

In FIG. 1, 1 is a turbo compressor (hereinafter simply referred to as a compressor), 2 is an impeller thereof, and 3 is an inlet vane provided in a suction pipe 11 on the suction side of the compressor 1.

4 is a vane control motor for controlling the opening degree of the inlet vane 3, and 4a is an opening degree indicator thereof.

5 is an electric motor that drives the compressor 1, and 6 is a condenser.

7 is an evaporator, and 8 is a heat exchanger tube inside this evaporator 7.

Cold water flows in and out of the heat exchanger tubes 8 as indicated by broken line arrows.

Reference numeral 9 indicates a flash duct related to the pressure reduction means, and reference numeral 10 indicates a refrigerant pipe line for sending refrigerant liquid to the evaporator.

Reference numeral 12 denotes a liquid level transmitter related to liquid level detection means for detecting the refrigerant liquid level submerging the heat transfer tube 8 of the evaporator 7 and outputting a signal. A flow 12a that rises and falls according to the liquid level of the refrigerant is provided in the container.

13 is a liquid level indicator related to liquid level indicating means for indicating the optimum refrigerant liquid level according to the load; hypochondriatically connected to the degree detection means.

14 is a control valve for adjusting the opening degree of the refrigerant pipe 10 on the evaporator inlet side, and 15 is a liquid level side means connected to the liquid level indicating means 3 and the control valve 14 in a hypostatic manner. This liquid level controller 15 compares the output signal of the liquid level transmitter 12 with the liquid level indicated by the liquid level indicator 13, and determines the opening degree of the control valve 14. It is something to be adjusted.

16.17 is an inlet/outlet 1 for cold water that enters and exits the heat exchanger tube 8.
Regarding the quality detection means, reference numeral 16 indicates an inlet temperature detection sensor, and reference numeral 17 indicates an outlet 1 quality detection sensor.

Next, the action will be explained.

In the centrifugal refrigerator shown in FIG. 1, an electric motor 5 rotates the impeller 2 of the compressor 1 to compress the refrigerant, and the compressed high-temperature, high-pressure refrigerant gas is guided into the condenser 6, indicated by the dashed arrow. It exchanges heat with the circulating cooling water and is condensed and liquefied. The liquefied refrigerant passes through the refrigerant pipe line 10, expands under reduced pressure in the flash duct 9 in the evaporator 57, enters and exits as indicated by the broken line arrow, absorbs the heat of the cold water flowing in the heat transfer tube 8, and evaporates into the suction pipe 11. After that, it is sucked into the compressor 1 again and this refrigeration cycle is repeated. Note that the solid arrows in the refrigeration cycle shown in FIG. 1(a) indicate the flow of refrigerant.

Such load fluctuations in the refrigeration cycle of a centrifugal chiller are
This appears as a temperature difference between the cold water entering and exiting the heat transfer tube 8 of the evaporator 7.

Therefore, the temperature difference between the inlet and outlet of the cold water is known from the temperatures detected by the inlet temperature detection sensor 16 and the outlet temperature detection sensor 17, and the liquid level indicator 13 determines the reference level according to the load in the evaporator 7 based on the temperature difference between the inlet and outlet of the chilled water. Indicates the refrigerant level.

On the other hand, the Q-plane transmitter 12 detects the refrigerant liquid level in the container communicating with the evaporator 7 using a float 12a.

The detection signal is output.

Therefore, the liquid level controller 15 compares the liquid level based on the output signal from the liquid level transmitter 12 with the reference liquid level indicated by the liquid level indicator 13, and adjusts the opening degree of the control valve 14. The amount of refrigerant liquid flowing into the evaporator 7 is controlled so that the refrigerant liquid level in the evaporator 7 becomes the optimum liquid level as a reference according to the load.

The refrigerant liquid level in the evaporator is shown by a dashed line in FIG. 1(b) when the load is 0 and when the load is 100%.

The reference refrigerant liquid level indicated by the liquid level indicator 13 is such that the refrigerant liquid level in the evaporator 7 is raised when the load is low, and the refrigerant liquid level in the evaporator 7 is lowered when the load is high, as described above. The load is changed from 0 to 100 by adjusting the opening of the control valve 14 controlled by the liquid level controller 15.
Continuously control between

According to this embodiment, when the load is low, the amount of refrigerant evaporation decreases, so the refrigerant liquid level in the evaporator is raised to wet the upper heat transfer tube, so that the heat transfer rate does not decrease and the refrigerator efficiency can be improved.

In addition, as the load increases, the amount of refrigerant evaporation increases, so
It also has the effect of lowering the refrigerant liquid level in the evaporator and preventing mist build-up due to an excessive rise in the liquid level.

Next, another embodiment of the present invention will be described with reference to FIG.

FIG. 2 is a block diagram of a centrifugal chiller equipped with a refrigerant level control device according to another embodiment of the present invention. In FIG. 1, the same reference numerals as in FIG. Since this is the same part as the example, its explanation will be omitted.

In the embodiment shown in FIG. 2, the refrigerant liquid level in the evaporator 7 is determined based on the opening degree of the inlet vane 3 provided on the suction pipe 11 side of the compressor 1 in order to detect the temperature difference between the cold water inlet and outlet of the embodiment shown in FIG. is configured to control.

The liquid level indicator 13' is drowsily connected to an opening indicator 4a installed in the vane control motor 4 of the inlet vane 3. Therefore, the liquid level indicator 13' is adjusted depending on the opening degree of the inlet vane 3.

Instructs the reference refrigerant liquid level in the evaporator 7 according to the load.

The liquid level controller 15, as previously explained in the embodiment shown in FIG. is compared, and the opening degree of the control valve 14 is adjusted to control the amount of refrigerant liquid flowing into the violet generator 7, so that the refrigerant liquid level in the evaporator 67 becomes the optimum liquid level as a reference according to the load. to control.

According to the embodiment shown in FIG. 2, the same effects as described in the embodiment shown in FIG. 1 can be expected.

In each of the above-mentioned implementations, devices such as the liquid level indicator 13, 13' as the 1M level indicating means and the liquid level controller 15 as the i-plane controlling means are used. Needless to say, a control means such as a microcomputer may be used as the means.

〔Effect of the invention〕

As described above, according to the present invention, by maintaining the refrigerant liquid level in the evaporator at an optimum level in accordance with load fluctuations, the heat transfer rate of the evaporator is prevented from being low -F during low loads, and It is possible to provide a refrigerant liquid level control device for a refrigerator that can prevent mist-up due to an excessive refrigerant liquid level and improve the efficiency of the refrigerator.

[Brief explanation of drawings]

FIG. 1(a) is a block diagram of a centrifugal chiller equipped with a refrigerant level control device according to an embodiment of the present invention, and FIG. 1(b) is
A schematic cross-sectional view of the evaporator section, Figure WJ2, is a configuration diagram of a turbo chiller equipped with a refrigerant level control device according to another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Compressor, 3... Inlet vane, 4a... Once indicator, 6... Condenser, 7... Evaporator, 8... Heat exchanger tube, 9... Flash duct, 10... Refrigerant pipe line, 11... Suction pipe.

Claims (1)

[Claims] 1. In a refrigerator equipped with a compressor, a condenser, a pressure reducing means, an evaporator, and refrigerant piping connecting these, the refrigerant liquid level in which the heat transfer tubes of the evaporator are immersed is set in the evaporator. A liquid level detecting means for detecting and outputting a signal, a liquid level indicating means for indicating an optimum refrigerant liquid level according to the load, and an output signal of the liquid level detecting means and a liquid level indicated by the liquid level indicating means. and a liquid level control means for adjusting the opening degree of the refrigerant pipe on the inlet side of the evaporator, so as to control the liquid level of the evaporator to the optimum liquid level according to load fluctuations on the refrigerator. A refrigerant liquid level control device for a refrigerator, characterized by comprising: 2. In the device described in claim 1, the liquid level indicating means connects the heat transfer tube in the evaporator to an inlet/outlet temperature detection means for circulating cold water, and detects the refrigerant in the evaporator based on the temperature difference between the inlet and outlet of the cold water. A refrigerant liquid level control device for a refrigerator that is configured to indicate the liquid level. 3. In the device described in claim 1, the liquid level indicating means is connected to an opening indicator that indicates the opening of the inlet vane provided on the suction pipe side of the compressor, and the liquid level indicating means is connected to an opening indicator that indicates the opening of the inlet vane, and A refrigerant liquid level control device for a refrigerator, which is configured to instruct the refrigerant liquid level in an evaporator according to the evaporator. 4. In any one of claims 1 to 3, the liquid level indicating means is configured to raise the refrigerant level in the evaporator when the load is low and to lower the refrigerant level in the evaporator when the load is high. A refrigerant liquid level control device for a refrigerator that is configured to indicate a reference liquid level.