CN110926073A

CN110926073A - Device and method for monitoring working medium state in operation of compression refrigeration system

Info

Publication number: CN110926073A
Application number: CN201811090853.3A
Authority: CN
Inventors: 孙艳丽; 宋涛; 高振欧
Original assignee: Qingdao Hengjia United Venture Capital Co Ltd
Current assignee: Qingdao Hengjia United Venture Capital Co Ltd
Priority date: 2018-09-19
Filing date: 2018-09-19
Publication date: 2020-03-27

Abstract

The invention provides a device and a method for monitoring the state of working medium in the operation of a compression refrigeration system, which adopts non-bearing connection for pipelines of a liquid storage tank and other parts of the refrigeration system and is used for monitoring the state of the refrigeration working medium in a mode of measuring the weight of the liquid storage tank in the operation of the system. The method comprises the steps of comparing the weight change parameters of the liquid storage tank before and after the compressor is started, comparing the change values of the high-pressure gauge and the low-pressure gauge, and judging whether the running state of the refrigeration system is normal or not through a human or a computer or implementing alarm or automatic control through gravity, tension and a pressure switch.

Description

Device and method for monitoring working medium state in operation of compression refrigeration system

Technical Field

The invention relates to a compression type refrigeration system, in particular to a device for monitoring the working medium state in operation and an application method thereof.

Background

In devices using a compression refrigeration system, such as an air conditioner, a refrigeration storage, etc., a pressure gauge is usually installed at a position where a pressure change of a working medium is large in order to monitor a state of the working medium in operation. Such as a high pressure gauge, a low pressure gauge, etc. In special occasions, such as an air conditioner used by an automobile, a refrigerant window is used for observing the flowing of bubbles carried by a refrigerant to acquire the operating state of a working medium. The detection mode is difficult to express the more exact state of the refrigerant.

For example, in an air conditioner using compression refrigeration, a refrigerator or the like, a liquid storage tank is provided in front of a throttle valve in order to obtain a good evaporation effect, and the liquid storage tank has a gas-liquid separation function. According to the characteristics of the refrigerating working medium, the refrigerant can be liquefied at a specific pressure at normal temperature; the refrigerant evaporates when the system pressure decreases. When a leakage occurs in the refrigeration system, the remaining margin is still evaporating to supplement and maintain the pressure until the leakage is nearly completely exhausted. The inherent characteristic of maintaining the pressure value makes the gradual leakage state of the working medium of the system in the initial most period unable to be found by means of a pressure gauge. For example, the refrigerant of a refrigeration house leaks, and the pressure gauge always expresses the same quantity value under the condition that the liquid storage tank has working medium storage capacity. The pressure gauge will not drop until the refrigerant is lost to the point where it can not supplement pressure. This situation has a number of disadvantages.

The refrigerant is not expected to leak to the air space, and the so-called green environment-friendly refrigerant is only relative. The refrigerating working medium is a high molecular polymer, has the active property at normal temperature and probably has the harm of destroying the natural environment unknown to human beings. From the perspective of users, the more green and environment-friendly the product, the more expensive the product, and the more useless the leakage loss, it is a waste.

The compressor of a pressure refrigeration plant is also heat-dissipating by means of the refrigeration generated by the system, at the end of the refrigeration-related zone. When the refrigerant leaks, the refrigerant capacity is reduced firstly at the compressor part, and the part is behind the low-pressure gauge in the direction of the working medium running path. Namely, the compressor part cannot be detected by the pressure gauge in the state of being incapable of receiving heat dissipation. This is a significant injury to the compressor.

Also, compressor overheating necessarily vaporizes compressor lubricant. The lubricating oil vapor is cooled and accumulated at a refrigerating part to generate an oil blocking phenomenon which is difficult to eliminate.

Furthermore, when the leakage is so severe that the pressure at some locations during operation is negative with respect to the ambient air, the leakage points at these locations may act as air entry points. The system is air-fed and the failure is more difficult to eliminate.

The refrigeration equipment has unknown faults which cannot be prevented and are difficult to repair as soon as possible, and conditions which influence life and business can occur to the air conditioner; in facilities such as a refrigerator, a great economic loss is caused by the generation of chemical and biological products.

The visual observation using the observation window is more difficult to obtain the quantity data, and the observation window is arranged at the front end which takes the compressor as a pressure starting point, even if a very small amount of refrigerating working medium exists, the mixed bubble liquid level is presented, and the leakage of the refrigerating working medium cannot be observed at all when the loss of the refrigerating working medium is not used up.

Disclosure of Invention

In order to find the phenomena of leakage, air intake, water intake, weakness of a compressor, malfunction of a throttle valve and the like as soon as possible in the operation of compressing a refrigerant system working medium, the invention provides a mode of monitoring the state of the refrigerant working medium by adopting weight measurement of a liquid storage tank. The method is characterized in that whether the running state of the refrigerating system is normal or not is judged manually or by a computer by comparing the weight change parameters of the liquid storage tank before and after the compressor is started and comparing the change values of the high-pressure and low-pressure gauges.

The device for carrying out the emphasizing on the liquid storage tank can also be a gravity switch and is directly used for alarming the loss of the refrigeration working medium or executing emergency protection control.

By contrasting the weight change of the liquid storage tanks before and after the compression refrigeration system is started, the liquefaction degree information of the refrigeration working medium in the running state can be obtained, an empirical value is established, and the leakage of the refrigeration working medium can be found in a mode of earlier-stage comparison. And the pressure gauges established at the high-pressure end and the low-pressure end can be referred to find out whether the refrigerant is doped with gases which are difficult to compress, such as air, water vapor and the like, and judge the compression capacity of the compressor, the throttling state of the throttling device, the heat dissipation capacity of the condenser, the heat dissipation capacity of the evaporator and the like.

The technical scheme for implementing the weight measurement of the liquid storage tank is as follows: establishing a non-load bearing connection to the tubing of the reservoir in the refrigeration system. This can be done by flexible tubing connections or by configuration arrangements such as a helical configuration, a swivel configuration, etc., to relieve the tubing from bearing the reservoir. And establishing a weight measuring spring support or hoisting weight measuring spring structure. Data is acquired or an action signal is executed through a pressure sensor or a pressure switch.

The technical scheme of the application method provided by the invention is as follows: the method comprises the steps of establishing pressure gauge, pressure sensor, pressure switch and other forms of detection or signal control corresponding to a high-pressure end and a low-pressure end of the working medium of the refrigerating system in operation, combining gravity detection or signal pickup of a liquid storage tank, and judging the working medium state of the system in operation through manual experience or computer. And the logical relations of high pressure and low pressure of the system working medium and the gravity of the liquid storage tank, such as AND, NOT, OR and the like, can be set through the circuit to execute direct control or alarm.

The invention has the beneficial effects that: the leakage can be found in the early stage of the leakage of the system refrigeration working medium, so that the damage of the refrigeration working medium to the nature can be avoided. There is no absolutely safe refrigeration working medium or refrigerant in the world, and the green and safety are only relative or the damage of unknown modern technical conditions. Theoretically, the high molecular polymer which can be compressed and liquefied at normal temperature is bound to be harmful to the natural environment state, prevent leakage in early stage and is beneficial to protecting the natural environment.

When the refrigerating working medium has a large surplus, the system is in a state of working medium surplus, and is in a positive pressure to the outside, and gas or moisture can be prevented from entering the system by early detection and prevention of leakage.

When a large surplus of refrigerant is found, the fault is found, the condition that the compressor loses the cooling state and an alarm or shutdown protection is provided can be avoided, the safety guarantee is provided for the arrangement of the compressor cooling by the refrigerating system, the leakage of the system is ensured, the pressure gauge cannot represent the fault, and the compressor loses the cooling state.

When the refrigerating working medium has a large surplus, the fault is found, the time length of the system for maintaining the refrigeration can be predicted according to the leakage degree, and the maintenance time is reasonably arranged. This is extremely important to the freezer that deposits a large amount of goods, and the user can dispatch goods and in time shift and prevent the goods of changing goods and lose.

When the refrigerating working medium has a large surplus, the fault is discovered, the leakage point can be maintained in a local isolation mode, the leaked refrigerating working medium is supplemented, and the maintenance fund is saved.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

In the figure 1, 1 is a compressor, 2 is a condenser, 3 is a liquid storage tank, 4 is a refrigerating working medium inlet, 5 is a refrigerating working medium outlet, 6 is a pressure sensor assembly or a pressure switch assembly, 7 is a connecting lead of the pressure sensor assembly or the pressure switch assembly, 8 is a refrigerating throttling device such as a throttling control valve or a capillary tube, 9 is an evaporator, 10 is a liquid level line in the liquid storage tank, 11 is a non-bearing connecting pipeline between the liquid storage tank and the condenser, and 12 is a non-bearing connecting pipeline between the liquid storage tank and the throttling valve.

Detailed Description

In fig. 1, a connecting pipeline (11) between the liquid storage tank and the condenser and a connecting pipeline (12) between the liquid storage tank and the throttle valve are in non-bearing connection, the connecting pipeline can be a universal connecting hose, and the influence of the pipeline connection on the weight measurement of the liquid storage tank can be reduced in a spiral shape or a folding shape. The unit weight is greatly increased after the refrigeration working medium is liquefied, so that the judgment of the conditions such as faults is not hindered due to slight involvement.

FIG. 1 (6) can be a base made of a pressure sensor and a corresponding spring or flexible base to have a side-weight function; they can be tension hoisting detection devices made of tension sensor components; they can also be direct alarms or direct controls of devices made of tension switches or pressure switches.

When the refrigerating system is in a shutdown state, the refrigerating working medium is irregularly evaporated in the whole system as far as possible to achieve pressure and gas-liquid balance. They can accumulate below one unit volume, but not all below the reservoir, to a significant extent from the weight of the system after operation. Due to the application of most compression refrigeration systems, except for an integrated window type air conditioner and the like, pipelines with different lengths are required to be connected according to field conditions, refrigeration working mediums with the same weight are filled, and the liquefaction values obtained by a liquid storage tank when the system operates are different. At this time, the action signal magnitude value can be judged and set by depending on the experience value established by the machine.

When the refrigerating system operates, the compressor (1) compresses the refrigerating working medium to the condenser (2), partial refrigerating working medium is liquefied due to the pressure generated by the heat dissipation effect of the condenser and the pressure limiting and blocking of the throttling device (8), and enters the liquid storage tank (3) from the refrigerating working medium inlet (4), and the opening of the refrigerating working medium outlet (5) is positioned below the liquid storage tank, so that all theoretically liquefied refrigerating working medium is gathered in the liquid storage tank, the liquefied working medium liquid level line (10) rises, the weight of the liquid storage tank is sharply increased, and the state information of the refrigerating working medium is obtained. The pressure sensor assembly or the pressure switch assembly (6) transmits the state information to relevant parts through a connecting wire (7) and provides judgment basis or direct control signals.

Claims

1. The device for monitoring the working medium state of the compression refrigeration system in operation comprises a liquid storage tank which is arranged in the refrigeration system, the front end of the liquid storage tank is connected with a condenser, and the rear end of the liquid storage tank is connected with a throttle valve.

2. The apparatus and method of use for monitoring the condition of a working fluid in the operation of a compression refrigeration system as claimed in claim (1) further comprising the step of establishing pressure gauges or sensors for detecting the high and low pressures of the system in the system, wherein the parameters obtained by combining the above means are used to determine the operation condition of the compression refrigeration system manually or by computer or to perform automatic control.