A sealing gas generating device for dry gas sealing of refrigeration compressor

Abstract

The present invention relates to the technical field of refrigeration compressors, and specifically to a sealing gas generating device for dry gas sealing of refrigeration compressors. The device comprises a condenser, a refrigerant receiving tank, an evaporator, a superheater, a temperature transmitter, a pressure transmitter and a distributed control system. The refrigerant outlet of the refrigeration compressor is connected to the refrigerant receiving tank via the condenser, the outlet of the refrigerant receiving tank is connected to the inlet of the evaporator, the outlet of the evaporator is connected to the inlet of the superheater, the outlet of the superheater is connected to the first-stage sealing gas supply interface of the refrigeration compressor, and a temperature transmitter and a pressure transmitter are arranged therebetween. The data output ends of the temperature transmitter and the pressure transmitter are connected to the data input end of the distributed control system, and the control signal output end of the distributed control system is respectively connected to the control signal input end of the evaporator and the superheater. The device reduces or even avoids the consumption, pollution and energy consumption caused by emissions during the start-up and shutdown of the refrigeration system, saves energy and reduces consumption, and has a long service life and good reliability.

Description

Technical Field

[0001] The invention relates to the technical field of refrigeration compressors, and in particular to a sealing gas generating device for dry gas sealing of a refrigeration compressor. Background Art

[0002] As the core equipment of the refrigeration system, the refrigeration compressor is a key factor in the stable operation and energy consumption of the entire refrigeration system. At present, during the start-up and shutdown of the compressor and under abnormal operating conditions, the first-stage sealing gas of the dry gas seal is an inert gas (such as nitrogen). Some inert gases enter the refrigeration system through the dry gas seal, and the inert gases will continue to accumulate during the refrigeration cycle. When the inert gas accumulates to a certain extent, it must be discharged until the content of the inert gas is reduced to meet the requirements, and the load of the refrigeration system can reach the design capacity. Along with the discharge of inert gases, part of the refrigerant is also discharged and cannot be recycled, and there is also pollution and energy consumption caused by the discharge. Summary of the invention

[0003] The purpose of the present invention is to address the defects of the prior art and provide a sealing gas generating device for dry gas seal of a refrigeration compressor. The high-pressure steam formed by gasification of the original refrigerant of the refrigeration compressor replaces the traditional inert gas as the first-level sealing gas of the dry gas seal, thereby reducing or even avoiding the consumption, pollution and energy consumption caused by emissions during the start-up and shutdown of the refrigeration system, saving energy and reducing consumption, and having a long service life and good reliability.

[0004] The present invention provides a sealing gas generating device for dry gas sealing of a refrigeration compressor, and its technical solution is as follows: it includes a condenser, a refrigerant receiving tank, an evaporator, a superheater, a temperature transmitter, a pressure transmitter and a distributed control system, the refrigerant outlet of the refrigeration compressor is connected to the refrigerant receiving tank through the condenser, the outlet of the refrigerant receiving tank is connected to the inlet of the evaporator, the outlet of the evaporator is connected to the inlet of the superheater, the outlet of the superheater is connected to the first-stage sealing gas supply interface of the refrigeration compressor dry gas sealing system station through a first pipeline, a temperature transmitter and a pressure transmitter are provided on the first pipeline, the data output ends of the temperature transmitter and the pressure transmitter are connected to the data input end of the distributed control system, the first control signal output end of the distributed control system is connected to the control signal input end of the evaporator, and the second control signal output end of the distributed control system is connected to the control signal input end of the superheater.

[0005] More preferably, a first one-way valve is provided between the evaporator outlet and the superheater inlet, and the outlet of the refrigeration compressor is connected to the rear stage of the first one-way valve through a second pipeline.

[0006] Preferably, when the pressure value output by the pressure transmitter is lower than the set value of the sealing gas pressure, the distributed control system outputs a first control signal to increase the heating intensity of the heating device in the evaporator;

[0007] When the pressure value output by the pressure transmitter is higher than the set value of the sealing gas pressure, the distributed control system outputs a first control signal to reduce the heating intensity of the heating device in the evaporator.

[0008] Preferably, the distributed control system calculates the current superheat according to the temperature value output by the temperature transmitter;

[0009] If the current superheat is higher than the set superheat of the evaporation gas, the distributed control system outputs a second control signal to reduce the superheat intensity of the superheater;

[0010] If the current superheat is lower than the set superheat of the evaporation gas, the distributed control system outputs a second control signal to increase the superheat intensity of the superheater.

[0011] More preferably, the outlet of the refrigerant receiving tank is connected to the inlet of the evaporator through a third pipeline, a liquid level regulating valve is provided on the third pipeline, and a liquid level transmitter is also provided on the evaporator, the data output end of the liquid level transmitter is connected to the data input end of the distributed control system, and the third control signal output end of the distributed control system is connected to the control signal input end of the liquid level regulating valve. When the liquid level in the evaporator is lower than the set value, the distributed control system controls the opening of the liquid level regulating valve to become larger, and vice versa.

[0012] Preferably, a second one-way valve is provided on the second pipeline.

[0013] Preferably, a third one-way valve is further provided upstream of the liquid level regulating valve.

[0014] The beneficial effects of the present invention are:

[0015] 1. The present invention adds an evaporator, a superheater, a distributed control system, a pressure transmitter, a temperature transmitter and other equipment to a conventional refrigeration system; utilizing the easy gasification characteristics of the refrigerant medium, according to the principle of matching the evaporation temperature and the evaporation pressure, the evaporation pressure of the refrigerant is controlled by controlling the evaporation temperature of the refrigerant in the evaporator; utilizing the superheat of the refrigerant to increase the superheat of the refrigerant, a continuous stream of refrigerant gas is generated in the refrigeration system, and this gas is transported to the first-stage sealing gas supply interface of the refrigeration compressor dry gas sealing system station through the first pipeline, thereby replacing the inert gas as the first-stage sealing gas of the dry gas seal. This solution avoids the contamination of the refrigerant in the refrigeration system when the inert gas is used as the sealing gas, and at the same time avoids the waste of refrigerant caused by the emission of inert gas, while saving energy and reducing consumption, and also has very considerable economic value. It has a simple structure, is easy to transform or build, saves energy and reduces consumption, has a long service life, is easy to maintain, and has good reliability.

[0016] 2. The present invention draws out a stream of high-pressure gas from behind the one-way valve at the outlet of the refrigeration compressor to the outlet of the evaporator. When the refrigeration system is just shut down, the downstream of the refrigeration compressor is filled with high-pressure refrigerant gas. This gas is drawn to the outlet of the evaporator to replace the above-mentioned evaporation gas, which can reduce the evaporation load. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the connection structure of the present invention.

[0018] In the figure: 1-evaporator, 2-superheater, 3-heating device, 4-temperature transmitter, 5-pressure transmitter, 6-distributed control system, 7-liquid level regulating valve, 8-liquid level transmitter, 9-first check valve, 10-second check valve, 11-third check valve, 12-refrigeration compressor, 13-condenser, 14-refrigerant receiving tank, 15-first pipeline, 16-second pipeline, 17-third pipeline DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0020] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0021] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0022] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0023] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. "Multiple" means "two or more".

[0024] Embodiment 1

[0025] Figure 1 Shows a preferred embodiment of the present application ( Figure 1 The structure diagram of a sealing gas generating device for a dry gas seal for a refrigeration compressor provided in the first embodiment of the present application is shown. For the convenience of explanation, only the part related to the present embodiment is shown, which is described in detail as follows:

[0026] A sealing gas generating device for dry gas sealing of a refrigeration compressor comprises a condenser 13, a refrigerant receiving tank 14, an evaporator 1, a superheater 2, a temperature transmitter 4, a pressure transmitter 5 and a distributed control system 6, wherein the refrigerant outlet of the refrigeration compressor 12 is connected to the refrigerant receiving tank 14 via the condenser 13, the outlet of the refrigerant receiving tank 14 is connected to the inlet of the evaporator 1, the outlet of the evaporator 1 is connected to the inlet of the superheater 2, the outlet of the superheater 2 is connected to the first-stage sealing interface of the dry gas sealing system station of the refrigeration compressor 12 via a first pipeline 15, the first pipeline 15 is provided with a temperature transmitter 4 and a pressure transmitter 5, the data output ends of the temperature transmitter 4 and the pressure transmitter 5 are connected to the data input end of the distributed control system 6, the first control signal output end of the distributed control system 6 is connected to the control signal input end of the evaporator 1, and the second control signal output end of the distributed control system 6 is connected to the control signal input end of the superheater 2.

[0027] Among them, the refrigeration compressor is a centrifugal compressor or a screw compressor suitable for dry gas sealing; the refrigerant refers to a gasifiable medium such as ammonia or propylene; the evaporator is a refrigerant gasification device equipped with electric heating or steam heating; the superheater is a steam heater or an electric heater used to increase the superheat of the refrigerant gas. The evaporation temperature of the evaporator is determined by the refrigerant saturation temperature corresponding to the required sealing gas pressure; the capacity of the superheater is considered based on a superheat of 50°C, which can be finally confirmed with the seal manufacturer during implementation.

[0028] The present invention adds an evaporator, a superheater, a distributed control system, a pressure transmitter, a temperature transmitter and other equipment to a conventional refrigeration system; utilizing the easy gasification characteristics of the refrigerant medium, according to the principle of matching the evaporation temperature and the evaporation pressure, the evaporation pressure of the refrigerant is controlled by controlling the evaporation temperature of the refrigerant in the evaporator; utilizing the superheat of the refrigerant to increase the superheat of the refrigerant, a continuous stream of refrigerant gas is generated in the refrigeration system, and this stream of gas is transported to the first-stage sealing interface of the refrigeration compressor dry gas sealing system station through the first pipeline, thereby replacing the inert gas as the first-stage sealing gas of the dry gas seal. This solution avoids the contamination of the refrigerant in the refrigeration system when the inert gas is used as the sealing gas, and at the same time avoids the waste of refrigerant caused by the emission of the inert gas, while saving energy and reducing consumption, and also has very considerable economic value. It has a simple structure, is easy to transform or build, saves energy and reduces consumption, has a long service life, is easy to maintain, and has good reliability.

[0029] In one embodiment, a first one-way valve 9 is provided between the outlet of the evaporator 1 and the inlet of the superheater 2 , and the outlet of the refrigeration compressor 12 is connected to the rear stage of the first one-way valve 9 through a second pipeline 16 .

[0030] The present invention draws out a stream of high-pressure gas from behind the one-way valve at the outlet of the refrigeration compressor to the outlet of the evaporator. When the refrigeration system is just shut down, the downstream of the refrigeration compressor is filled with high-pressure refrigerant gas. This gas is drawn to the outlet of the evaporator to replace the above-mentioned evaporation gas, which can reduce the evaporation load.

[0031] In one embodiment, when the pressure value output by the pressure transmitter 5 is lower than the set value of the sealing gas pressure, the distributed control system 6 outputs a first control signal to increase the heating intensity of the heating device 3 in the evaporator 1;

[0032] When the pressure value output by the pressure transmitter 5 is higher than the set value of the sealing gas pressure, the distributed control system 6 outputs a first control signal to reduce the heating intensity of the heating device 3 in the evaporator 1 .

[0033] In one embodiment, the distributed control system 6 calculates the current superheat according to the temperature value output by the temperature transmitter 4;

[0034] If the current superheat is higher than the set superheat of the evaporation gas, the distributed control system 6 outputs a second control signal to reduce the superheat intensity of the superheater 2;

[0035] If the current superheat degree is lower than the set superheat degree of the boil-off gas, the distributed control system 6 outputs a second control signal to increase the superheat intensity of the superheater 2 .

[0036] In one embodiment, the outlet of the refrigerant receiving tank 14 is connected to the inlet of the evaporator 1 through a third pipeline 17, and a liquid level regulating valve 7 is provided on the third pipeline 17. A liquid level transmitter 8 is also provided on the evaporator 1, and a data output end of the liquid level transmitter 8 is connected to a data input end of the distributed control system 6, and a third control signal output end of the distributed control system 6 is connected to a control signal input end of the liquid level regulating valve 7. When the liquid level in the evaporator 1 is lower than the set value, the distributed control system 6 controls the opening of the liquid level regulating valve 7 to increase, and vice versa.

[0037] In one embodiment, a second one-way valve 10 is disposed on the second pipeline 16 .

[0038] In one embodiment, a third one-way valve 11 is further provided upstream of the liquid level regulating valve 7 .

[0039] A one-way valve is installed between the refrigerant receiving tank and the evaporator, a one-way valve is installed between the evaporator and the superheater and before the high-pressure gas intersection, and a one-way valve is installed on the high-pressure gas pipeline leading from the outlet of the refrigeration compressor; the function of the above one-way valves is to prevent the backflow of high-pressure gas.

[0040] The working principle of this device is as follows:

[0041] The evaporator is added downstream of the refrigerant receiving tank, and the superheater is arranged on the downstream pipeline of the evaporator. The temperature measuring point and the pressure measuring point are arranged downstream of the superheater. Part of the liquid phase refrigerant enters the evaporator from the refrigerant receiving tank through the liquid level difference or pressure difference. The evaporator is a refrigerant gasification device equipped with electric heating or steam heating. After the liquid refrigerant is heated, saturated gas is generated in the evaporator. The heating load of the evaporator is controlled by the downstream pressure signal. When the pressure downstream of the superheater is lower than the set value of the sealing gas pressure, the evaporation temperature can be increased by increasing the heating intensity of the evaporator heating device, thereby achieving the effect of increasing the evaporation pressure in the evaporator. The maximum pressure is about 1.66MPaG, a saturated pressure at 40°C. The liquid level in the evaporator is guaranteed by controlling the opening of the liquid level regulating valve through the liquid level signal of the liquid level transmitter. When the liquid level in the evaporator is lower than the set value, the liquid level signal controls the opening of the liquid level regulating valve to increase, otherwise it decreases. The saturated refrigerant gas enters the downstream superheater for superheating, so that the gas has a certain degree of superheat to avoid condensation when used as a sealing gas; the superheater is a steam-heated superheater or an electrically heated superheater; the heat load of the superheater is controlled by the temperature of its downstream. If the current superheat is higher than the superheat set for the evaporating gas, the distributed control system reduces the superheat intensity of the superheater; if the current superheat is lower than the superheat set for the evaporating gas, the distributed control system increases the superheat intensity of the superheater. After the refrigerant gas passes through the superheater, the superheat degree is about ~50℃, and the maximum pressure is 1.66MpaG. This gas source meets the requirements of the first-stage sealing gas of the dry gas seal in terms of pressure, temperature and quality. The superheated gas that has passed through the superheater can replace the inert gas as the first-stage sealing gas of the dry gas seal. In addition, a high-pressure gas is drawn from the outlet check valve of the refrigeration compressor to the outlet of the evaporator; when the refrigeration system is just stopped, the downstream of the refrigeration compressor is full of high-pressure refrigerant gas, and this gas is drawn to the outlet of the evaporator to replace the above-mentioned evaporating gas, thereby reducing the evaporation load.

[0042] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A sealing gas generating device for dry gas sealing of a refrigeration compressor, Features: The invention comprises a condenser (13), a refrigerant receiving tank (14), an evaporator (1), a superheater (2), a temperature transmitter (4), a pressure transmitter (5) and a distributed control system (6); the refrigerant outlet of a refrigeration compressor (12) is connected to the refrigerant receiving tank (14) via the condenser (13); the outlet of the refrigerant receiving tank (14) is connected to the inlet of the evaporator (1); the outlet of the evaporator (1) is connected to the inlet of the superheater (2); the outlet of the superheater (2) is connected to the refrigeration compressor (12) via a first pipeline (15); The first pipeline (15) is connected to the first-stage sealing gas supply interface of the dry gas sealing system station of the machine (12); a temperature transmitter (4) and a pressure transmitter (5) are provided on the first pipeline (15); the data output ends of the temperature transmitter (4) and the pressure transmitter (5) are connected to the data input end of the distributed control system (6); the first control signal output end of the distributed control system (6) is connected to the control signal input end of the evaporator (1); and the second control signal output end of the distributed control system (6) is connected to the control signal input end of the superheater (2).

2. The sealing gas generating device for the dry gas seal for the refrigeration compressor according to claim 1, Features: A first one-way valve (9) is provided between the outlet of the evaporator (1) and the inlet of the superheater (2), and the outlet of the refrigeration compressor (12) is connected to the rear stage of the first one-way valve (9) via a second pipeline (16).

3. The sealing gas generating device for dry gas seal for refrigeration compressor according to claim 1, Features: When the pressure value output by the pressure transmitter (5) is lower than the set value of the sealing gas pressure, the distributed control system (6) outputs a first control signal to increase the heating intensity of the heating device (3) in the evaporator (1); When the pressure value output by the pressure transmitter (5) is higher than the set value of the sealing gas pressure, the distributed control system (6) outputs a first control signal to reduce the heating intensity of the heating device (3) in the evaporator (1).

4. The sealing gas generating device for dry gas seal for refrigeration compressor according to claim 1, Features: The distributed control system (6) calculates the current superheat according to the temperature value output by the temperature transmitter (4); If the current superheat is higher than the set superheat of the evaporating gas, the distributed control system (6) outputs a second control signal to reduce the superheat intensity of the superheater (2); If the current superheat degree is lower than the set superheat degree of the evaporating gas, the distributed control system (6) outputs a second control signal to increase the superheat intensity of the superheater (2).

5. The sealing gas generating device for dry gas seal for refrigeration compressor according to claim 1, Features: The outlet of the refrigerant receiving tank (14) is connected to the inlet of the evaporator (1) via a third pipeline (17). A liquid level regulating valve (7) is provided on the third pipeline (17). The evaporator (1) is also provided with a liquid level transmitter (8). The data output end of the liquid level transmitter (8) is connected to the data input end of the distributed control system (6). The third control signal output end of the distributed control system (6) is connected to the control signal input end of the liquid level regulating valve (7). When the liquid level in the evaporator (1) is lower than the set value, the distributed control system (6) controls the opening of the liquid level regulating valve (7) to increase, and vice versa.

6. The sealing gas generating device for dry gas seal for refrigeration compressor according to claim 2, Features: A second one-way valve (10) is provided on the second pipeline (16).

7. The sealing gas generating device for dry gas seal for refrigeration compressor according to claim 5, Features: A third one-way valve (11) is also provided upstream of the liquid level regulating valve (7).

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