CN110686742A

CN110686742A - Device capable of testing gas-liquid ratio after passing through throttling device

Info

Publication number: CN110686742A
Application number: CN201910975810.1A
Authority: CN
Inventors: 陈清清; 潘江
Original assignee: China University of Metrology
Current assignee: China Jiliang University; China University of Metrology
Priority date: 2019-10-15
Filing date: 2019-10-15
Publication date: 2020-01-14

Abstract

A device for measuring the ratio of liquid to gas in the refrigerant in the pipeline after passing through the throttle device under the working state of the refrigerating system. The device is divided into a non-test pipeline and a test pipeline. Comprises a flowmeter, a throttling device, a pipeline, an electromagnetic valve, a gas-liquid separation device, an open liquid storage container and a pressure gauge. The test pipeline firstly utilizes a gas-liquid separation device to separate gas-phase refrigerant and liquid-phase refrigerant, the liquid phase is stored in a container with known bottom area, and the bottom pressure of the container is measured. At this time, the respective mass flow rates of the gas phase and the liquid phase may be calculated from the total flow rate of the refrigerant and the measured pressure, and the ratio may be finally obtained.

Description

Device capable of testing gas-liquid ratio after passing through throttling device

Technical Field

The invention relates to a device capable of measuring a gas-liquid ratio, which is mainly used for detecting the gas-liquid ratio of a refrigerant after passing through a throttling device in the refrigeration industry.

Background

Refrigeration products widely permeate into life and industry, such as air conditioners, refrigerators, cold stores and the like, and all belong to refrigeration devices. The four major components of the refrigerating device are respectively a compressor, a condenser, a throttle valve and an evaporator which are sequentially connected by pipelines to form a closed system, and a refrigerant continuously circularly flows in the system and is subjected to state change to exchange heat with the outside. After the refrigerant passes through the throttle valve, the system pressure is reduced, and the refrigerant can be changed into gas-liquid two-phase flow from single-liquid-phase flow and then enters the evaporator to work. In the evaporator, the liquid phase absorbs heat through latent heat of vaporization, and the gas phase absorbs heat through sensible heat, and the specific heat capacity of the liquid phase and the specific heat capacity of the gas phase are greatly different, so that when the gas-liquid ratio entering the evaporator is different, the measured performance of the evaporator is greatly different. Therefore, under the condition that the gas-liquid phase content in the throttled refrigerant cannot be accurately obtained, the performance of the evaporator is judged to have certain deviation only by the heat exchange amount of the evaporator. However, there is no device capable of detecting the ratio of refrigerant gas to liquid after the throttle valve. Therefore, the development of such a device capable of measuring the gas-liquid ratio of the refrigerant after the throttle valve in an operating condition would be of great benefit to the optimization and performance detection of the evaporator.

Disclosure of Invention

The invention aims to provide a device capable of measuring the gas-liquid ratio after passing through a throttling valve, which can detect the gas-liquid ratio in a throttled refrigerant in the working state of a refrigeration system.

In order to solve the technical problems, the invention provides the following technical scheme:

the device for measuring the ratio of refrigerant gas to liquid after passing through the throttle valve under working condition includes flow meter, throttle device, pipeline, switch valve, gas-liquid separator, container with known bottom area, pressure gauge and casing. The flow meter for measuring the flow of two-phase flow is not developed at present, so that the flow meter for directly measuring the flow behind the throttling device is not advisable, therefore, the flow meter is arranged in front of the throttling valve to measure the total flow of single liquid phase, the gas-liquid separation is carried out after the throttling valve, and then the gas phase and the liquid phase are separately measured. The working idea of the device is as follows: the method comprises the steps of firstly closing a test pipeline to enable a non-test pipeline above the test pipeline to start running, starting the test pipeline when a system runs stably, starting timing at the same time, enabling a refrigerant to flow into the test pipeline under the action of gravity, enabling gas-liquid two phases to be thoroughly separated through a gas-liquid separation device, discharging a gas phase into the device, enabling a liquid phase to flow into an open liquid storage container with a known bottom area, and enabling the container to be attached with a pressure gauge. Because the density of the liquid-phase refrigerant is known, the height of the liquid-phase refrigerant in the open container can be calculated by combining the reading of the pressure gauge, and further, the volume flow and the mass flow of the liquid-phase refrigerant can be calculated.

At this time, the value of the total refrigerant mass flow is the difference between the readings Δ G of the cumulative flow meter multiplied by the time, and multiplied by the refrigerant density ρ, which is recorded as m_{General assembly}＝ΔG×t×ρ。

The bottom area of the open reservoir is recorded as S and the reading difference of the pressure gauge is recorded as delta P_{Liquid for treating urinary tract infection}According to the formula Δ P_{Liquid for treating urinary tract infection}P g h Δ P in this period can be obtained_{Liquid for treating urinary tract infection}/ρg，m_{Liquid for treating urinary tract infection}＝S×ΔP_{Liquid for treating urinary tract infection}/g。

The mass flow rate of the gas-phase refrigerant is therefore: m is_{Qi (Qi)}＝m_{General assembly}-m_{Liquid for treating urinary tract infection}And the ratio of gas phase to liquid phase can be obtained by calculation.

When the device is used for testing the gas-liquid ratio of the throttled fluid, the device is used as a part of a refrigerating system, and can be used as a liquid accumulator of the refrigerating system due to the fact that the container 9 has a certain volume. When the non-test pipeline works, a certain amount of liquid-phase refrigerant is stored at the bottom of the container. When the test pipeline is switched to work, the refrigerant stored at the bottom of the container 9 enters the evaporator through the pipeline, and the liquid-phase refrigerant in the evaporator is ensured to continuously flow in. The testing time is short, so the bottom refrigerant storage can meet the requirement of the system on the refrigerant during the normal work in the testing process, the size of the bottom space is related to the size of the device shell, and the design selection can be carried out according to different requirements.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

FIG. 2 is a schematic view of the inside of the liquid storage container with an opening of the test pipeline.

The reference numbers in the figures are: 1. a flow meter; 2. a throttling device; 3. a pipeline; 4. a pipeline; 5. an electromagnetic valve; 6. a gas-liquid separation device; 7. an open container of known floor area; 8. a pipeline; a device housing; 10. and a pressure gauge.

Detailed Description

In order to enable researchers in the technical field to better understand the technical scheme of the invention, the invention will be further described in detail with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, the gas-liquid ratio detection device used after the throttling device of the invention mainly comprises a flowmeter 1, a throttling device 2, a pipeline 3, a pipeline 4, an electromagnetic valve 5, a gas-liquid separation device 6, an open liquid storage container 7, a pipeline 8, a device shell 9 and a pressure gauge 10. Wherein the non-test line region includes the pipe 4, the apparatus bottom space and the pipe 8, and the test line means includes the solenoid valve 5, the gas-liquid separation apparatus 6, the container 7 of known bottom area and the pressure gauge 10. Before the system is started, the electromagnetic valve 5 of the test pipeline needs to be closed, and meanwhile, the non-test pipeline starts to run. The refrigerant flows through the pipeline 3 and the pipeline 4, is stored in a cavity at the bottom of the device, and enters the evaporator to participate in the normal operation of the system after the refrigerant at the bottom reaches the height of the pipeline 8. After the working condition of the system is stable, the electromagnetic valve 5 of the test pipeline is opened, the refrigerant flows into the test pipeline, the liquid phase flows into the open liquid storage container 7 through the gas-liquid separation device 6, when the reading of the pressure gauge 10 changes, the reading of the pressure gauge is recorded for the first time, the accumulated flow reading of the flow meter 1 is recorded at the same time, after a certain time t, the reading of the pressure gauge is recorded for the second time, and the accumulated flow reading of the flow meter 1 is recorded at the same time. The difference value of the two readings of the flowmeter is multiplied by the density of the refrigerant, and the product is the total mass of the refrigerant flowing through the test pipeline at the time t; and calculating the difference value of the two readings of the pressure gauge to obtain the liquid level h of the liquid phase flowing into the open liquid storage container within the time t, and multiplying the liquid level h by the bottom area S of the open liquid storage container and the density rho of the refrigerant to obtain the quality of the liquid phase refrigerant flowing through the test pipeline within the time t. The gas-liquid phase ratio of the refrigerant after passing through the throttling device can be obtained through calculation.

Claims

1. The device capable of measuring the gas-liquid ratio is characterized in that a flowmeter is arranged in front of a main pipeline throttling device, a refrigerant is divided into a working pipeline and a testing pipeline after passing through the throttling device, an electromagnetic valve for opening and closing, a gas-liquid separation device, an open container with a known bottom area and an external stainless steel sealed shell are arranged.

2. The flowmeter of claim 1, wherein the flow meter is arranged before the throttling device and is used for measuring the total flow of the refrigerant.

3. The throttle device of claim 1, wherein: the throttling device to be tested can be replaced by itself.

4. The two lines of claim 1, wherein: the two pipelines are arranged in parallel, the upper pipeline is a non-testing pipeline, the lower pipeline is a testing pipeline, and an electromagnetic valve is installed on the testing pipeline and used for opening and closing the testing pipeline.

5. The non-test line of claim 1, wherein: the tail end of a non-test pipeline in the device is communicated with the cavity of the device. When the device is in a non-test state, refrigerant may flow into the device cavity through the non-test line.

6. The test line of claim 1, wherein: an electromagnetic valve for pipeline switch is installed, the tail end of the electromagnetic valve is connected with a gas-liquid separation device, and the gas-liquid separation device is positioned in an open container with known bottom area.

7. An open top container of known floor area as set forth in claim 1 wherein: the bottom of the container is known, the bottom is provided with a pressure gauge, and the upper outlet is communicated with the device and fixed inside the device.

8. The housing of claim 1, wherein: the material is stainless steel, and the whole leakproofness is good, can change its volume size according to the test demand of refrigerant.