WO2018082347A1

WO2018082347A1 - Water chilling unit

Info

Publication number: WO2018082347A1
Application number: PCT/CN2017/094320
Authority: WO
Inventors: 陈改芳
Original assignee: 重庆美的通用制冷设备有限公司; 美的集团股份有限公司
Priority date: 2016-11-02
Filing date: 2017-07-25
Publication date: 2018-05-11
Also published as: CN206222747U

Abstract

Provided is a water chilling unit (100), comprising: a compressor (1), an oil separator (4) which is connected to a condenser (3), an evaporator (2) and an oil return device (5). In the oil return device (5), a lead-in end (a) of a Venturi ejector (51) is connected to an oil outlet port (41) of the oil separator (4) by means of a first connecting pipe (52), a negative pressure end (b) is connected to a liquid outlet port (21) of the evaporator (2) by means of a second connecting pipe (53), and a jet end (c) is connected to an oil return port (11) of the compressor (1) by means of a third connecting pipe (54), two ends of a fourth connecting pipe (55) are connected to the oil outlet port (41) of the oil separator (4) and the oil return port (11) of the compressor (1) respectively.

Description

Chiller

Technical field

The invention relates to the field of refrigeration equipment, and in particular to a water chiller.

Background technique

In a full-liquid or falling-film chiller, the refrigerant in the evaporator takes the shell, the chilled water goes through the tube, and the refrigerant evaporates and heats outside the tube. After the refrigerant evaporates, the lubricating oil carried by the refrigerant cannot return to the compressor due to the low returning speed, and a large amount is stored in the evaporator, which affects the evaporation effect and reduces the efficiency of the unit.

In the existing oil return system, the refrigerant in the condenser is generally used to drive the ejector to perform the ejector returning oil. In this way, the amount of oil returned is large, but the amount of liquid refrigerant returned to the tank is increased, and the oil is diluted. The concentration, and no oil separation and purification, will cause a part of the oil in the refrigerant gas, causing the system pipeline to run oil. Another way is to use the high pressure oil and gas in the compressor discharge part (gathering chamber) as the ejector source to separate the oil from the refrigerant mixture and the refrigerant mixture in the compressor suction chamber and then accumulate the oil at the bottom. The transmission of the compressor, due to the use of high-pressure oil and gas as an injection source, causes the liquid refrigerant content in the oil return to be high, diluting the oil concentration.

Summary of the invention

The present application aims to solve the technical problems existing in the prior art. To this end, the present invention aims to provide a chiller which can reduce the oil content of the refrigerant in the evaporator and can increase the COP value of the unit.

A chiller according to the present invention includes: a compressor having a return port; an evaporator having a liquid outlet; an oil separator connected to the condenser, the oil separator having an oil outlet An oil returning device, the oil returning device comprising: a venturi ejector, a first nozzle, a second nozzle, a third nozzle, and a fourth nozzle, the introduction end of the venturi ejector passing through the first nozzle Connected to the oil outlet of the oil separator, the negative pressure end of the venturi ejector is connected to the liquid outlet of the evaporator through the second nozzle, the jet end of the venturi ejector The third connecting pipe is connected to the oil return port of the compressor, and the two ends of the fourth connecting pipe are respectively connected to the oil outlet of the oil separator and the oil return port of the compressor.

According to the chiller of the embodiment of the present invention, by providing two oil return passages between the oil separator and the compressor, one passage directly returns oil, and the other passage drives the lubricating oil in the evaporator to return oil through the venturi ejector. It can not only reduce the oil content in the heat exchanger of the chiller, improve the heat exchange efficiency, improve the COP value of the unit, but also reduce the refrigerant content in the oil return, avoiding the high refrigerant content and the concentration of the diluted oil in the return oil. problem.

In some embodiments, the chiller further includes: controlling the oil outlet to communicate with one of the first nozzle and the fourth nozzle, and controlling the oil outlet and the first nozzle A control member that is disconnected from the other of the fourth nozzles.

Optionally, a first solenoid valve is connected in series to the first nozzle.

Optionally, a second solenoid valve is connected in series to the fourth connector.

In some embodiments, an oil level detecting member is further disposed in the compressor, and the oil level detecting member is electrically connected to the control member to control the operation of the control member.

In some embodiments, when the oil level detecting member detects that the oil level of the compressor is greater than or equal to the first oil level value, the control member is configured to control the oil outlet and the first nozzle Connected; and when the oil level detecting member detects that the oil level of the compressor is less than the first oil level value, the control member is configured to control the oil outlet to communicate with the fourth nozzle.

In another specific embodiment, when the oil level detecting component detects that the oil level of the compressor is greater than or equal to the first oil level value, the control member is configured to control the oil outlet and the first Taking over communication; when the oil level detecting member detects that the oil level of the compressor is less than the first oil level value and greater than or equal to the second oil level value, the control member is configured to control the oil outlet and the The fourth take-over is connected; when the oil level detecting member detects that the oil level of the compressor is less than the second oil level value and lasts for a first preset time, the compressor stops running.

Specifically, when the oil level detecting member detects that the oil level of the compressor rises from less than the first oil level value to greater than or equal to the first oil level value, and the oil level of the compressor remains greater than or equal to the first oil The control member is configured to control the oil outlet to communicate with the first nozzle when the bit value is for a second predetermined time.

Optionally, the oil level detecting member is a double oil level switch.

In some embodiments, the oil separator is disposed between the compressor and the condenser; or the oil separator is built into the compressor or the condenser.

The additional aspects and advantages of the invention will be set forth in part in the description which follows.

DRAWINGS

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from

1 is a schematic structural view of a chiller according to an embodiment of the present invention;

Figure 2 is a schematic view of a compressor oil level in accordance with one embodiment of the present invention;

3 is a schematic view of a compressor oil level in accordance with another embodiment of the present invention.

Reference mark:

Water chiller 100,

Compressor 1, oil return port 11, evaporator 2, liquid outlet 21, condenser 3, oil separator 4, oil outlet 41, oil return device 5, venturi ejector 51, introduction end a, negative pressure The end b, the jet end c, the first connecting pipe 52, the second connecting pipe 53, the third connecting pipe 54, the fourth connecting pipe 55, the first electromagnetic valve 61, and the second electromagnetic valve 62.

detailed description

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer to the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are intended to be illustrative of the invention and are not to be construed as limiting.

A chiller 100 according to an embodiment of the present invention will be described below with reference to FIG. 1, which may be a screw chiller.

Understandably, in large chillers, the compressor is the core component of the entire system, powering the entire system cycle. During the operation of the compressor, a certain amount of lubricating oil must be injected. The lubricating oil mainly functions of lubrication, cooling, sealing, dispersing stress, and preventing rust. During the operation of the unit, oil will be mixed into the refrigerant, which will bring about two effects. On the one hand, the heat exchange effect of the heat exchanger is reduced. On the other hand, the oil is continuously mixed into the refrigerant, and the oil in the oil tank is less and less. It may cause the unit to fail to operate normally, so it is necessary to set up the oil return device in the chiller.

The chiller 100 according to an embodiment of the present invention, as shown in FIG. 1, includes a compressor 1, an oil separator 4 connected to the condenser 3, an evaporator 2, and an oil returning device 5. Among them, the compressor 1 has a return port 11, the evaporator 2 has a liquid outlet 21, and the oil separator 4 has an oil outlet 41.

Referring to Fig. 1, the oil returning device 5 includes: a venturi ejector 51, a first nozzle 52, a second nozzle 53, a third nozzle 54, and a fourth nozzle 55, and the introduction end a of the venturi ejector 51 passes the first The nozzle 52 is connected to the oil outlet 41 of the oil separator 4, and the negative pressure end b of the venturi ejector 51 is connected to the liquid outlet 21 of the evaporator 2 through the second nozzle 53, the jet end of the venturi ejector 51 c is connected to the oil return port 11 of the compressor 1 through a third connecting pipe 54, and both ends of the fourth connecting pipe 55 are connected to the oil outlet 41 of the oil separator 4 and the oil return port 11 of the compressor 1, respectively.

It should be noted that the structure and working principle of the compressor 1, the condenser 3, the oil separator 4 and the evaporator 2 are well known to those skilled in the art, and the venturi ejector 51 can be disclosed in the prior art. The structure of the venturi ejector, the working principle of which can also be disclosed by the prior art, and therefore will not be described again here.

In the embodiment of the present invention, the oil returning device 5 is equivalent to providing two oil return passages, and the other is that the oil separator 4 directly returns oil through the fourth connecting pipe 55, and the oil returning speed is fast, and when the oil quantity in the compressor 1 is insufficient, The other is that the oil separator 4 drives the lubricating oil in the evaporator 2 to return oil through the venturi ejector 51, which can reduce the refrigerant contained in the evaporator. The amount of oil. The connection between the two channels can be set according to specific needs.

The oil separator 4 connected to the condenser 3 becomes the main source of the oil return of the compressor 1. The oil is returned from the oil separator 4, on the one hand, the refrigerant content in the oil return can be reduced, and the refrigerant content in the oil return is avoided, The concentration of the diluted oil; on the other hand, the oil content in the refrigerant is lowered, so that the heat exchange efficiency of the condenser 3 can be improved. By using the oil separator 4 as a high-pressure power source, the lubricating oil deposited in the evaporator 2 can be introduced into the compressor 1 through the venturi ejector 51 to improve the evaporation effect. Thereby, the COP value of the unit can be increased.

According to the chiller 100 of the embodiment of the present invention, two oil return passages are provided between the oil separator 4 and the compressor 1, one passage directly returns oil, and the other passage drives the evaporator 2 through the venturi ejector 51. Lubricating oil can not only reduce the oil content in the heat exchanger of the chiller 100, improve the heat exchange efficiency, improve the COP value of the unit, but also reduce the refrigerant content in the oil return, avoiding the high refrigerant content in the return oil. The problem of diluting the concentration of oil.

In the embodiment of the present invention, the oil separator 4 may be externally disposed, or the built-in oil separator 4 may be additionally disposed. For example, the oil separator 4 is independently provided and disposed between the compressor 1 and the condenser 3; for example, the oil separator 4 may be built in the compressor 1, in which the compressor 1 is provided with the oil separator 4; The oil separator 4 can be built in the condenser 3.

In the embodiment of the present invention, the two passages of the oil returning device 5 can be simultaneously connected, and the two passages can also be connected under the control of the control member, and in some cases, the two passages can be controlled to be disconnected.

In the embodiment of the present invention, a control device may be disposed in the chiller 100 to control the two passages of the oil return device 5 in accordance with the need for oil return.

For example, the control device may include a flow control member (not shown), and the unit may connect the flow control member in series on the first connection 52 and the fourth connection 55 of the oil return device 5, respectively. When the amount of oil in the compressor 1 is insufficient, the flow rate on the fourth nozzle 55 can be controlled to increase, and the flow rate on the first nozzle 52 is decreased; when the amount of oil in the compressor 1 is sufficient, the flow rate on the fourth nozzle 55 can be controlled to decrease. The flow on one of the nozzles 52 increases.

For another example, the first solenoid valve 61 may be connected in series on the first nozzle 52. At this time, the second solenoid valve 62 may be connected in series to the fourth nozzle 55, and the flow control member may be connected in series to the fourth nozzle 55.

Alternatively, a second solenoid valve 62 may be connected in series to the fourth nozzle 55. At this time, the flow control member may be connected in series to the first nozzle 52.

In some embodiments, the chiller 100 further includes: for controlling the oil outlet 41 to communicate with one of the first nozzle 52 and the fourth nozzle 55, and controlling the oil outlet 41 and the first nozzle 52 and the fourth nozzle Another disconnected control in 55. That is, in this embodiment, only one of the two passages of the oil returning device 5 is in communication.

The control member can have various structures. For example, a three-way valve can be connected between the first connecting pipe 52 and the fourth connecting pipe 55. The three-way valve can control the oil outlet 41 of the oil separator 4 to communicate with only one of the connecting pipes. The three-way valve can constitute the above control member.

Alternatively, as shown in FIG. 1, the first solenoid valve 61 is connected in series with the first solenoid valve 61, and the second solenoid valve 62 is connected in series to the fourth nozzle 55. The first solenoid valve 61 and the second solenoid valve 62 are interlocked with each other. That is, when the first electromagnetic valve 61 is opened, the second electromagnetic valve 62 is turned off, and when the first electromagnetic valve 61 is turned off, the second electromagnetic valve 62 is opened. At this time, the first electromagnetic valve 61 and the second electromagnetic valve 62 are combined into the above-described control member, and controlled by the electromagnetic valve, the control is easy and the reliability is high.

In some embodiments, an oil level detecting member (not shown) is further disposed in the compressor 1, and the oil level detecting member is electrically connected to the control member to control the operation of the control member. That is to say, the control member can control the communication between the two passages of the oil returning device 5 according to the actual oil level of the compressor 1. This type of control can meet the actual operation requirements of the compressor 1 at any time, and adjust the oil return amount in real time, so that the balance between the compressor return oil and the evaporator oil output can be achieved.

In combination with the detection results of the oil level detecting member, the chiller 100 has various control forms.

As shown in FIG. 2, in some embodiments, when the oil level detecting member detects that the oil level of the compressor 1 is greater than or equal to the first oil level value H1, the control member is configured to control the oil outlet 41 and the first nozzle 52. When the oil level detecting member detects that the oil level of the compressor 1 is less than the first oil level value H1, the control member is configured to control the oil outlet 41 to communicate with the fourth connecting tube 55.

In this embodiment, as shown in FIG. 2, the first oil level value H1 can be understood as an identification boundary for whether or not the lubricating oil in the compressor 1 is sufficient. When the oil level in the compressor 1 is greater than or equal to the first oil level value H1, it indicates that the amount of oil in the compressor 1 is sufficient, the control member communicates with the first nozzle 52, the fourth nozzle 55 is disconnected, and the oil separator 4 is ejector through the venturi. The device 51 drives the lubricating oil in the evaporator 2 to return oil, thereby reducing the oil content in the refrigerant in the evaporator as much as possible; when the oil level in the compressor 1 is lower than the first oil level value H1, indicating the oil in the compressor 1 The amount is not enough, the control member communicates with the fourth connecting pipe 55, the first connecting pipe 52 is disconnected, and the oil separator 4 directly returns oil, so as to meet the oil returning demand of the compressor 1 as quickly as possible.

In this embodiment, when the oil level detecting member detects that the oil level of the compressor 1 rises from less than the first oil level value H1 to be greater than or equal to the first oil level value H1, and the oil level of the compressor 1 remains greater than or equal to the first When the oil level value H1 is long for the second predetermined time, the control member is configured to control the oil outlet 41 to communicate with the first nozzle 52.

As shown in FIG. 3, in other specific embodiments, when the oil level detecting member detects that the oil level of the compressor 1 is greater than or equal to the first oil level value H1, the control member is configured to control the oil outlet 41 and the first nozzle. 52 communicating; when the oil level detecting component detects that the oil level of the compressor 1 is less than the first oil level value H1 and greater than or equal to the second oil level value H2, the control member is configured to control the oil outlet 41 to communicate with the fourth nozzle 55; When the oil level detecting member detects that the oil level of the compressor 1 is less than the second oil level value H2 and lasts for a first predetermined time, the compressor 1 stops operating.

In this embodiment, as shown in FIG. 3, the first oil level value H1 can be understood as an identification boundary for the sufficient lubricating oil in the compressor 1, and the second oil level value H2 can be understood as whether the lubricating oil in the compressor 1 is lacking. Identification line.

When the oil level in the compressor 1 is greater than or equal to the first oil level value H1, it indicates that the amount of oil in the compressor 1 is sufficient; when the oil level in the compressor 1 is less than the second oil level value H2, it indicates that the amount of oil in the compressor 1 is insufficient. When the oil level in compressor 1 is less than When the first oil level value H1 is greater than or equal to the second oil level value H2, it indicates that the amount of oil in the compressor 1 is insufficient, but it is not so high that the compressor 1 can still operate.

If the amount of oil in the compressor 1 is sufficient, the control member communicates with the first connecting pipe 52 and disconnects the fourth connecting pipe 55, and the oil separator 4 drives the lubricating oil in the evaporator 2 to return oil through the venturi ejector 51, thereby as much as possible Reducing the oil content in the refrigerant in the evaporator;

If the amount of oil in the compressor 1 is lacking and the oil is deficient for a first predetermined time, the compressor 1 is shut down and protected;

If the amount of oil in the compressor 1 is insufficient, but still can support the normal operation of the compressor, the control member communicates with the fourth nozzle 55, disconnects the first nozzle 52, and the oil separator 4 directly returns oil, thereby satisfying the compression as quickly as possible. Machine 1 needs oil back.

In the embodiment of the present invention, the first preset time and the second preset time may all be changed by actual conditions, and specific values thereof are not limited.

The structure and working principle of the chiller 100 will be described below with reference to a specific embodiment.

In this embodiment, as shown in FIG. 1, the oil return system in the chiller 100 mainly includes four parts: a compressor 1, a condenser 3, an evaporator 2, and an oil returning device 5. The compressor 1 has a return port 11, an oil level detecting member is disposed on the compressor 1, and the oil level detecting member is a double oil level switch. An oil separator 4 is built in the condenser 3, and the separated oil is discharged from the oil outlet 41, and the liquid outlet 21 is provided at the bottom of the evaporator 2.

In the description of the present invention, it is to be understood that the orientation or positional relationship of the terms "top", "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, only for the purpose of The invention is not limited by the scope of the invention, and is not intended to be a limitation of the invention. Moreover, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include one or more of the features either explicitly or implicitly.

The oil returning device 5 comprises two main parts: a fourth connecting pipe 55 for direct oil return of the oil separator 4 and a venturi ejector 51, both of which are connected to the oil return port 11 of the compressor 1. The introduction end a of the venturi ejector 51 is connected to the oil separator 4 through a first nozzle 52, and the negative pressure end b of the venturi ejector 51 is connected to the evaporator 2 through a second nozzle 53, the venturi ejector 51 The jet end c is connected to the compressor 1 via a third nozzle 54.

Wherein, the first connecting pipe 52 has a first electromagnetic valve 61 connected in series, and the fourth connecting pipe 55 has a second electromagnetic valve 62 connected in series. The first solenoid valve 61 and the second solenoid valve 62 are electrically connected to the dual oil level switch, respectively, to be controlled to open and close by the dual oil level switch.

This embodiment provides a reliable method for controlling the oil return of the evaporator 2, and the specific control process is as follows:

When the unit is in normal operation, the high oil level switch of the compressor 1 is closed, the second solenoid valve 62 of the fourth connection 55 of the oil returning device 5 is closed, and the first solenoid valve 61 of the first connection tube 52 of the oil returning device 5 is opened. After the high-pressure oil filtered by the built-in oil separator 4 passes through the venturi ejector 51, the negative pressure formed sucks up the mixed liquid of the oil and the refrigerant at the bottom of the evaporator 2, and returns to the compressor 1 together with the high-pressure oil. Port 11.

When the high oil level switch of the compressor 1 is turned off, the second solenoid valve 62 of the fourth nozzle 55 of the oil returning device 5 is opened, and the first solenoid valve 61 of the first nozzle 52 of the oil returning device 5 is closed, and the oil separator 4 is closed. Direct oil return, speed up oil return;

After the oil return device 5 starts to quickly return oil, if the high oil level switch of the compressor 1 is changed from the off state to the closed state, and the high oil level switch is continuously closed for 5 minutes, the unit returns to the normal operation state, that is, the unit is restored to The second solenoid valve 62 is closed on the fourth nozzle 55, and the first solenoid valve 61 is opened on the first nozzle 52.

When the compressor 1 low oil level switch is also open and the disconnection time is up to 90s, the compressor 1 is protected from shutdown.

According to the chiller of the embodiment of the invention, the lubricating oil in the evaporator is returned to the compressor 1 through reliable oil return control of the evaporator, thereby improving the heat exchange effect of the evaporator and ensuring reliable operation of the system.

In the description of the present invention, the terms "connected" and "connected" are to be understood broadly, and may be, for example, a fixed connection, a detachable connection, or an integral; Connections can also be electrical connections; they can be directly connected or indirectly connected via an intermediate medium. The specific meaning of the above terms in the present invention can be understood in a specific case by those skilled in the art.

In the description of the present specification, the description of the terms "embodiment", "example" and the like means that a specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. . In the present specification, the schematic representation of the above terms does not necessarily mean the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

While the embodiments of the present invention have been shown and described, the embodiments of the invention may The scope of the invention is defined by the claims and their equivalents.

Claims

A chiller characterized in that it comprises:

a compressor having a return port;

An evaporator having a liquid outlet;

An oil separator connected to the condenser, the oil separator having an oil outlet;

An oil returning device, the oil returning device comprising: a venturi ejector, a first nozzle, a second nozzle, a third nozzle, and a fourth nozzle, the introduction end of the venturi ejector passing through the first nozzle An oil outlet of the oil separator is connected, and a negative pressure end of the venturi ejector is connected to a liquid outlet of the evaporator through the second nozzle, and a jet end of the venturi ejector passes The third nozzle is connected to the oil return port of the compressor, and two ends of the fourth nozzle are respectively connected to the oil outlet of the oil separator and the oil return port of the compressor.
The chiller according to claim 1, further comprising: controlling the oil outlet to communicate with one of the first nozzle and the fourth nozzle, and controlling the oil outlet a control member that is disconnected from the other of the first nozzle and the fourth nozzle.
The chiller according to claim 1 or 2, wherein the first solenoid is connected in series with the first solenoid valve.
The chiller according to any one of claims 1 to 3, wherein a second solenoid valve is connected in series to the fourth nozzle.
The chiller according to claim 2, wherein said compressor is further provided with an oil level detecting member, said oil level detecting member being electrically connected to said control member to control the operation of said control member.
The chiller according to claim 5, wherein the control member is configured to control the oil discharge when the oil level detecting member detects that the oil level of the compressor is greater than or equal to a first oil level value a port is connected to the first connector; and

The control member is configured to control the oil outlet to communicate with the fourth nozzle when the oil level detecting member detects that the oil level of the compressor is less than the first oil level value.
The chiller according to claim 5 or 6, wherein when the oil level detecting member detects that the oil level of the compressor is greater than or equal to the first oil level value, the control member is configured to control the The oil outlet is in communication with the first nozzle;

The control member is configured to control the oil outlet and the fourth nozzle when the oil level detecting member detects that the oil level of the compressor is less than the first oil level value and greater than or equal to the second oil level value Connected

When the oil level detecting member detects that the oil level of the compressor is less than the second oil level value and lasts for a first predetermined time, the compressor stops operating.
The chiller according to claim 6 or 7, wherein the oil level detecting member detects that the oil level of the compressor rises from less than the first oil level value to greater than or equal to the first oil level value, and The control member is configured to control the oil outlet to communicate with the first nozzle when the oil level of the compressor remains greater than or equal to the first oil level for a second predetermined time.
The chiller according to any one of claims 5-7, wherein the oil level detecting member is a double oil level switch.
The chiller according to claim 1, wherein said oil separator is disposed between said compressor and said condenser; or said oil separator is built in said compressor or said condensing In the device.