WO2017063549A1

WO2017063549A1 - Automatic air extraction system, refrigerating unit comprising system and automatic air extraction method

Info

Publication number: WO2017063549A1
Application number: PCT/CN2016/101799
Authority: WO
Inventors: 王升; 王娟; 刘华; 张治平; 董小林
Original assignee: 珠海格力电器股份有限公司
Priority date: 2015-10-15
Filing date: 2016-10-11
Publication date: 2017-04-20
Also published as: CN105115203B; CN105115203A

Abstract

Provided are an automatic air extraction system, a refrigerating unit comprising the system and an automatic air extraction method. The automatic air extraction system comprises a gas-liquid separation device (1), a gas collection tank (2), an ejector (3), an electromagnetic valve device (4), a vacuum pump (5) and also comprises a liquid level control system (6) connected to the gas-liquid separation device (1), the liquid level control system (6) controls the air extraction operation according to the relationship between the liquid level change inside the gas-liquid separation device (1) and the pressure inside the gas collection tank (2). The automatic air extraction system not only improves the automation level of a unit, but also reduces the cost, and improves the reliability of the unit.

Description

Automatic pumping system, refrigeration unit having the same, and automatic pumping method

Technical field

The invention belongs to the technical field of refrigeration, and particularly relates to an automatic air extraction system, a refrigeration unit having the same, and an automatic air extraction method.

Background technique

In the current refrigeration unit, in order to maintain the refrigeration and heating capacity of the unit, the unit's own vacuum is put forward very high requirements. Once the vacuum is destroyed, the output of the unit will be greatly attenuated, so the refrigeration unit usually needs One or more sets of automatic pumping systems are arranged to extract non-condensable gases inside the unit. The pumping system of existing refrigeration units usually has the following forms.

The first option is an automatic pumping system that uses ejector ejector and solenoid valve control. As shown in Fig. 1, the solution uses the ejector 3 to illuminate the non-condensable gas inside the unit, the pressure sensor 15 detects the internal pressure of the gas collecting box 2, and realizes the non-condensable gas inside the unit by the switching action between the electromagnetic valves. . The scheme uses three solenoid valves and a pressure sensor to control the pumping process. The advantage is that the degree of automation is high, and the safety of the pumping system is high, but the disadvantage is that the pressure of the gas to be measured is low, and the pressure sensor has higher requirements. Therefore, the investment is large.

The second scheme is an ejector ejector and a pumping system for automatic hydrogen discharge from the palladium tube. As shown in FIG. 2, the solution uses the ejector 3 to illuminate the internal non-condensable gas of the unit, automatically discharges the hydrogen inside the gas collection box 2 through the palladium tube 16, and measures the internal pressure of the gas collection box 2 through the U-type vacuum gauge 18. After the pressure reaches the set value, the vacuum pump is turned on to extract non-condensable gas inside the unit. Although the overall cost of the scheme is not high, the degree of automation is not high, and the palladium pipe can only automatically exclude the hydrogen inside the unit, and does not exclude other non-condensable gases, and the cost of replacing the palladium pipe is not low.

Therefore, based on the above-mentioned deficiencies in the prior art, it is necessary to study and design an automatic pumping system capable of improving the automation level and reducing the investment cost thereof, a refrigeration unit having the system, and an automatic pumping method.

Summary of the invention

Therefore, the technical problem to be solved by the present invention is to overcome the defects that the pumping system in the prior art cannot simultaneously improve its automation level and reduce the investment cost, thereby providing a novel automatic pumping system and a refrigeration unit having the same. And automatic pumping method.

The invention provides an automatic air extraction system, which comprises a gas-liquid separation device, a gas collection box, an ejector, a solenoid valve device and a vacuum pump. The automatic air extraction system further comprises a liquid level control connected to the gas-liquid separation device. In the system, the liquid level control system controls the pumping operation according to a change in the internal liquid level of the gas-liquid separation device and a pressure relationship inside the gas collection box.

Further, the liquid level control system includes a liquid level detecting device.

Further, the liquid level detecting device includes a pumping liquid level probe.

Further, the pumping liquid level probe includes an upper pumping liquid level probe and a lower pumping liquid level probe.

Further, the liquid level detecting device is further provided with a low liquid level alarm device.

Further, the gas-liquid separation device comprises a primary gas-liquid separator and a secondary gas-liquid separator.

Further, an input end of the primary gas-liquid separator is connected to an output end of the ejector along a fluid flow direction, and a gas output end of the primary gas-liquid separator is connected to the gas collection tank .

Further, an input end of the secondary gas-liquid separator is connected to a bottom end of the primary gas-liquid separator, and an output end of the secondary gas-liquid separator is divided into a gas output end and a liquid output end, A gas output is connected to the input of the ejector.

Further, the solenoid valve device is disposed on a pipeline between the gas collection tank and the vacuum pump.

Further, the solenoid valve device includes a two-way solenoid valve and a three-way solenoid valve.

Further, the primary gas-liquid separator and the secondary gas-liquid separator are connected.

Further, the two-way solenoid valve and the three-way solenoid valve are sequentially disposed in the fluid flow direction on the line between the gas collection box and the vacuum pump.

The present invention also provides a refrigeration unit comprising the aforementioned automatic air extraction system.

Further, the refrigeration unit is an absorption refrigeration unit, including a condenser, an evaporator, an absorber, and a generator, and further includes the foregoing automatic air extraction system, and both the suction end and the return end of the automatic air extraction system Connected to the absorber.

Further, the absorption refrigeration unit uses a lithium bromide solution as an absorbent.

The invention also provides an automatic air pumping method, which utilizes the aforementioned automatic air pumping system to pump the air pumping device, and the specific steps are: using an ejector to inject the gas in the air pumping device into the gas The liquid separation device detects the liquid level in the gas-liquid separation device by a liquid level control system connected to the gas-liquid separation device, and performs evacuation using a vacuum pump.

Further, when the liquid level is lower than the lower limit position, it means that the gas in the air suction device is excessive, and then the vacuum pump is turned on to evacuate the gas output end of the gas-liquid separation device.

Further, when the liquid level is higher than the upper limit position, it indicates that the vacuum degree in the pumping device satisfies the demand, and then the vacuum pump is turned off to stop the pumping action.

The invention provides an automatic air extraction system, a refrigeration unit with the same, and an automatic air extraction method, which have the following beneficial effects:

1. An automatic air extraction system according to the present invention not only improves the automation level of the unit, but also saves the use of the solenoid valve and the pressure sensor, thereby reducing the cost.

2. An automatic air extraction system according to the present invention improves the reliability of the unit and effectively prevents undesirable problems such as pumping action caused by abnormal operation of the vacuum pump.

DRAWINGS

1 is a schematic structural view of an air suction system of an absorption refrigeration unit according to a first aspect of the prior art;

2 is a schematic structural view of an air suction system of an absorption refrigeration unit according to a second aspect of the prior art;

Figure 3 is a schematic structural view of an automatic air extraction system of the present invention;

Figure 4 is a schematic view showing the structure of an absorption refrigeration unit having the automatic pumping system of the present invention.

The reference numerals in the figure are indicated as:

1. Gas-liquid separation device; 11. Primary gas-liquid separator; 12. Secondary gas-liquid separator; 2. Gas collection box; 3. Ejector; 4. Solenoid valve device; 41, 2-way solenoid valve; 42, three-way solenoid valve; 5, vacuum pump; 6, liquid level control system; 61, pumping liquid level probe; 611, upper pumping liquid level probe; 612, lower pumping liquid level probe; 7, condensation 8, evaporator, 9, absorber; 10, generator; 13, oil separator; 14, solution pump; 15, pressure sensor; 16, palladium tube; 17, manual valve; 18, U-type vacuum gauge.

detailed description

The specific embodiments of the present invention are further described in detail below with reference to the drawings and embodiments. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

As shown in FIG. 3, the present invention provides an automatic air extraction system including a gas-liquid separation device 1, a gas collection box 2, an ejector 3, a solenoid valve device 4, and a vacuum pump 5, which further includes a connection to the a liquid level control system 6 of the gas-liquid separation device 1, the liquid level control system 6 controlling the pumping operation according to a pressure relationship between the liquid level inside the gas-liquid separation device 1 and a pressure inside the gas collection box 2 (this The relationship between the points refers to the liquid level will decrease with the pressure in the gas collecting box, and the liquid level will increase when the pressure is lowered). According to the automatic air extraction system of the present invention, by connecting the liquid level control system to the gas-liquid separation device, the liquid level on the gas-liquid separation device can be effectively detected, and whether or not the pumping operation is performed according to the liquid level condition is determined. Not only can it effectively improve the automation level of the unit, but also save the use of solenoid valves and pressure sensors, thus effectively reducing costs. The gas collecting box 2 is connected between the gas-liquid separating device 1 and the vacuum pump 5 for collecting the separated gas, and the electromagnetic valve device 4 is disposed between the gas collecting box 2 and the vacuum pump 5 for The gas in the pipeline is controlled.

Further, the liquid level control system 6 includes a liquid level detecting device. The liquid level detecting device is for detecting a liquid level condition inside the gas-liquid separating device, and may preferably include a detecting device and a display device that displays a liquid level condition.

Further, the liquid level detecting device includes a pumping liquid level probe 61. The suction level probe 61 is used to detect the level of the liquid level in the gas-liquid separation device.

Further, the pumping liquid level probe includes two, an upper pumping liquid level probe 611 and a lower pumping liquid level probe 612, respectively. The lower pumping liquid level probe 612 is disposed at a lower limit position of the gas-liquid separation device for detecting the liquid in the gas-liquid separation device Whether the bit falls to the lower limit position, if the liquid level drops to the lower limit position, indicating that the gas in the pumping device (preferably the absorption refrigerating container of the present invention) is excessive, and the degree of vacuum does not satisfy the required requirement, and the control is performed at this time. The system should start the operation of the vacuum pump 5 according to the detected information to extract the gas in the device to meet the required vacuum standard; the upper pumping liquid level probe 611 is disposed at the upper limit position of the gas-liquid separation device. , for detecting whether the liquid level in the gas-liquid separation device rises to the upper limit position, and if the liquid level rises to the upper limit position, indicating that the pumping device (the present invention is preferably an absorption refrigerating container) has extracted enough The gas, at which time the degree of vacuum in the pumped equipment has reached the desired state, so the control system can stop the vacuum pump 5 based on the detected information to prevent extraction of excess non-gas such as liquid.

Further, the liquid level detecting device is further provided with a low liquid level alarm device (not shown). When the liquid level in the gas-liquid separation device drops to the lower limit position, a corresponding alarm signal is issued through the low liquid level alarm device, indicating that the vacuum degree in the pumping device is not satisfactory, and the vacuum pump 5 is urgently required to open the device. The gas in the process is pumped to achieve the required vacuum. Preferably, the lower limit level and the alarm level here can be set to a liquid level, and the alarm level can also be slightly lower than the lower limit level.

Preferably, the gas-liquid separation device 1 includes a primary gas-liquid separator 11 and a secondary gas-liquid separator 12. The function of the two-stage gas-liquid separator is to further separate the gas and liquid on the basis of the first-stage gas-liquid separator.

Preferably, along the direction of fluid flow, the output of the ejector 3 is connected to the input of the primary gas-liquid separator 11, and the gas in the pumping device is emitted through the ejector 3 ( Aspirating), then the gas enters the primary gas-liquid separator 11 for gas-liquid separation, and the gas output end of the primary gas-liquid separator 11 (ie, at the top end thereof) is connected to the gas collection tank 2 for The separated gas is collected into the gas collection box 2.

Preferably, the input end of the secondary gas-liquid separator 12 is connected to the bottom end (liquid output end) of the primary gas-liquid separator 11, and the output end of the secondary gas-liquid separator 12 is divided into gas An output end and a liquid output end, the gas output end being connected to the input end of the ejector 3 to recirculate the re-separated gas into the ejector 3 and then to the first-stage gas-liquid separator 11 The liquid output is connected to the pumped device. The two-stage separator arrangement can further separate the gas-liquid two phases, the gas enters the gas collection tank, and the liquid returns to the pumping equipment.

Further, the solenoid valve device 4 is disposed on a line between the gas collection box 2 and the vacuum pump 5. The air flow path between the gas collecting box 2 and the vacuum pump 5 can be effectively controlled by providing the solenoid valve device 4. The solenoid valve device 4 is controlled to be opened or closed by the liquid level control system.

Further, the solenoid valve device 4 includes a two-way solenoid valve 41 and a three-way solenoid valve 42 located behind the two-way solenoid valve 41 in the fluid flow direction. The two-way solenoid valve acts to isolate the air and ensure the vacuum. The three-way solenoid valve 42 can be used to switch between different branches.

As shown in Figure 4, the present invention also provides a refrigeration unit that also includes the aforementioned automatic air extraction system. The automatic pumping system can be used to pump (vacuum) the refrigeration unit.

Preferably, the refrigeration unit is an absorption refrigeration unit comprising a condenser 7, an evaporator 8, an absorber 9 and a generator 10, which further comprises the aforementioned automatic pumping system, the pumping end of the automatic pumping system and The return ends are each connected to the absorber 9. The condenser 7, the evaporator 8, the absorber 9 and the generator 10 together constitute an absorption refrigerating container, and the automatic pumping system performs the pumping (vacuum) action on the absorption refrigerating container.

Preferably, the absorption refrigeration unit uses a lithium bromide solution as an absorbent.

Further, the absorption refrigeration unit further includes an oil separator disposed between the three-way solenoid valve and the vacuum pump for separating the oil in the pumped gas. A solution pump 14 is further connected to the bottom of the absorption refrigerating container, and the other end of the solution pump is connected to the ejector, and the other circuit connected in parallel with the path is connected to the generator.

The present invention also provides an automatic pumping method that utilizes the aforementioned automatic pumping system to evacuate the pumped equipment. Preferably, the pumping device is an absorption refrigerating container.

Preferably, the working principle of the automatic air extraction system of the present invention (the liquid level control system for opening and closing) is as follows:

1. When the unit is in normal operation, after the pumping is completed, the internal pressure of the first-stage gas-liquid separator 11 is the lowest, which is the internal saturated vapor pressure of the unit, and the internal pumping operation probe of the liquid level control system 6 is in the on state. When the liquid level is high (the internal pressure of the gas collecting box is low, it is in the normal position); as the ejector 3 is launched, the non-condensable gas inside the unit is extracted, and the internal pressure of the gas-liquid separation device 1 rises. When the liquid level drops and the pressure in the gas-liquid separation device 1 reaches the pumping set pressure, the pumping liquid level probe is disconnected. At this time, the pressure in the gas collecting tank reaches the corresponding pressure value with the set liquid level, indicating The pressure in the pumping apparatus is high, the pumping operation is performed, and the pumping operation is started.

2. Firstly, the vacuum pump 5 is turned on when pumping. Because the vacuum requirement of the unit is high, the warm pump operation is first performed to make the vacuum pump 5 run to the optimal working state. When the warm pump is turned on, the two-way solenoid valve 41 is closed, and the three-way electromagnetic valve is turned off. The valve 42 is opened; after the warm pump is finished, the three-way solenoid valve 42 is first closed, and the oil separator 13 is evacuated. Preferably, the pumping time is set to 5 min to ensure that the gas inside the oil separator 13 and the pipeline are Pumped out. After the end, the two-way solenoid valve 41 is opened to evacuate the gas collection box. The two-way solenoid valve 41 functions to isolate air and vacuum.

3. When the vacuum pump 5 has poor pumping effect due to poor pumping condition, in the worst case, when the two-way solenoid valve 41 is opened and the air flows back to the gas collecting box 2, the low level alarm is passed through the liquid level control system 6. The two-way solenoid valve 41 is opened and closed, thereby preventing air from entering the unit, and timely repairing the vacuum pump 5 to ensure normal operation of the unit, thereby improving the reliability of the pumping system.

It will be readily understood by those skilled in the art that the above various preferred embodiments can be freely combined and superimposed without conflict.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope. The above is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention. It should also be considered as the scope of protection of the present invention.

Claims

An automatic air extraction system comprising a gas-liquid separation device (1), a gas collection box (2), an ejector (3), a solenoid valve device (4), and a vacuum pump (5), characterized in that: The pumping system further includes a liquid level control system (6) connected to the gas-liquid separation device (1), the liquid level control system (6) according to the internal liquid level change and the gas liquid separation device (1) The pressure relationship inside the gas collecting box (2) controls the pumping operation.
The automatic air extraction system according to claim 1, characterized in that said liquid level control system (6) comprises a liquid level detecting means.
The automatic air extraction system according to claim 2, wherein said liquid level detecting means comprises a pumping liquid level probe (61).
The automatic pumping system of claim 3 wherein said pumping level probe comprises an upper pumping level probe (611) and a lower pumping level probe (612).
The automatic air extraction system according to any one of claims 2 to 4, characterized in that the liquid level detecting device is further provided with a low liquid level alarm device.
The automatic air extraction system according to any one of claims 1 to 5, characterized in that the gas-liquid separation device (1) comprises a primary gas-liquid separator (11) and a secondary gas-liquid separator (12) ).
The automatic air extraction system according to claim 6, characterized in that the output end of the ejector (3) is connected to the input end of the primary gas-liquid separator (11) in the direction of fluid flow, The gas output end of the primary gas-liquid separator (11) is connected to the gas collection tank (2).
The automatic air extraction system according to claim 6 or 7, wherein the input end of the secondary gas-liquid separator (12) is connected to the bottom end of the primary gas-liquid separator (11). The output of the secondary gas-liquid separator (12) is divided into a gas output end and a liquid output end, the gas output end being connected to the input end of the ejector (3).
The automatic air extraction system according to any one of claims 1 to 8, characterized in that the solenoid valve device (4) is disposed between the gas collection box (2) and the vacuum pump (5) On the pipeline.
The automatic air extraction system according to any one of claims 1 to 9, characterized in that the solenoid valve device (4) comprises a two-way solenoid valve (41) and a three-way solenoid valve (42).
The automatic air extraction system according to claim 6, characterized in that said primary gas-liquid separator (11) and said secondary gas-liquid separator (12) are connected.
The automatic air extraction system according to claim 10, wherein said two-way solenoid valve (41) and said three-way solenoid valve (42) are sequentially disposed in said gas collection tank along a fluid flow direction ( 2) On the line between the vacuum pump (5).
A refrigeration unit characterized by comprising the automatic air extraction system according to any one of claims 1 to 12.
The refrigeration unit according to claim 13, wherein said refrigeration unit is an absorption refrigeration unit comprising a condenser (7), an evaporator (8), an absorber (9) and a generator (10). Both the pumping end and the return end of the automatic pumping system are connected to the absorber (9).
The refrigeration unit according to claim 14, wherein said absorption refrigeration unit employs a lithium bromide solution as an absorbent.
An automatic pumping method, characterized in that the pumping device is pumped by the automatic pumping system according to any one of claims 1 to 12, the specific step is: using an ejector (3) The gas in the pumping device is ejected, enters the gas-liquid separation device (1), and is used in the gas-liquid separation device (1) by a liquid level control system (6) connected to the gas-liquid separation device (1) The liquid level is detected and pumped using a vacuum pump (5).
The automatic pumping method according to claim 16, characterized in that, when the liquid level is lower than the lower limit position, the vacuum pump (5) is turned on to evacuate the gas output end of the gas-liquid separation device (1).
The automatic pumping method according to claim 16 or 17, wherein when the liquid level is higher than the upper limit position, the vacuum pump (5) is turned off to stop the pumping operation.