Liquid recycling structure of liquid ring vacuum pump based on mechanical seal

Abstract

The invention provides a liquid recycling structure of a liquid ring vacuum pump based on mechanical seal, and belongs to the technical field of liquid ring vacuum pumps. The problem that in the prior art, working liquid at the mechanical sealing position of a liquid ring vacuum pump leaks to pollute the environment is solved. According to the liquid ring vacuum pump based on the mechanical seal liquid recovery structure, the liquid ring vacuum pump comprises a pump body and a rotating shaft rotationally arranged in the pump body, mechanical seal assemblies are arranged between the two ends of the rotating shaft and the pump body respectively, and the liquid recovery structure comprises two end covers which cover the two ends of the rotating shaft respectively and are connected with the pump body; a closed cavity containing the mechanical sealing assembly is formed between the end cover and the pump body, and the two cavities communicate with a liquid inlet of the pump body through a first liquid return pipe and a second liquid return pipe correspondingly. The liquid ring vacuum pump has the advantage that leaked liquid at the mechanical sealing position of the liquid ring vacuum pump can be recycled.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid ring vacuum pumps, and relates to a liquid recovery structure for a liquid ring vacuum pump based on mechanical seals. Background Art

[0002] A liquid ring vacuum pump is a variable-volume vacuum pump that uses a liquid as an intermediate medium for energy conversion to pump gas. An eccentric rotor with fixed vanes is installed in its cavity. The continuously supplied water or liquid in the cavity is driven to rotate, forming a liquid ring concentric with the stator wall inside the stator wall. Therefore, the liquid ring vacuum pump needs to seal the rotating shaft that supports the rotor to prevent the working liquid from leaking out.

[0003] In order to avoid leakage of the working liquid, the prior art generally adopts a shaft sealing method with a mechanical seal assembly between the two ends of the rotating shaft and the pump body. The mechanical seal assembly includes main components such as a dynamic ring, a static ring, and a spring. Among them, the dynamic ring is installed on the rotating shaft through interference fit or a sealing ring to form a radial static seal to prevent the liquid from leaking axially. The static ring is fixedly connected to the pump body, and a static seal is formed with the pump body by using a sealing ring, etc., to ensure the sealing performance between the static ring and the pump body. At the same time, the end faces of the dynamic ring and the static ring are closely attached under the action of the spring, and a dynamic seal surface is formed between the dynamic ring and the static ring by the pressing force of the spring, so as to form a static seal between the rotating shaft and the dynamic ring, a static seal between the pump body and the static ring, and a dynamic seal between the dynamic ring and the static ring to jointly ensure the sealing performance. However, after the above shaft sealing method is used for a period of time, there are phenomena such as wear of the dynamic ring and the static ring and seal aging, resulting in the failure of the mechanical seal, and the working liquid leaks from the mechanical seal to the outside of the pump body, thus still causing the working liquid to leak out and polluting the environment. Summary of the Invention

[0004] The purpose of the present invention is to address the above problems existing in the prior art and propose a liquid recovery structure for a liquid ring vacuum pump based on mechanical seals. The technical problem to be solved by the present invention is how to realize the recycling of the liquid leaking from the mechanical seal of the liquid ring vacuum pump.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A liquid recovery structure for a liquid ring vacuum pump based on mechanical seals. The liquid ring vacuum pump includes a pump body and a rotating shaft rotatably arranged in the pump body. Mechanical seal assemblies are respectively arranged between the two ends of the rotating shaft and the pump body. The liquid recovery structure is characterized in that it includes two end covers respectively covering the two ends of the rotating shaft and connected to the pump body. A closed chamber accommodating the mechanical seal assembly is formed between the end cover and the pump body, and the two chambers are respectively communicated with the liquid inlet of the pump body through a first liquid return pipe and a second liquid return pipe.

[0007] When the liquid ring vacuum pump is in operation, the pressure at its liquid inlet is lower than the atmospheric pressure, forming a negative pressure state. The liquid recovery structure of this liquid ring vacuum pump based on mechanical seals forms a sealed chamber by setting end caps at the mechanical seal leakage points at both ends of the rotating shaft to physically isolate the contact between the leaked liquid and the environment and centrally collect the leaked liquid. At the same time, two independent first liquid return pipes and second liquid return pipes are set to connect the two chambers to the liquid inlet of the pump body respectively. Thus, using the negative pressure suction at the liquid inlet of the pump body as the driving force and without additional power devices, the leaked liquid in the two chambers is actively sucked back into the pump body to realize a closed-loop circulation circuit of the leaked liquid, thereby realizing the recycling of the leaked liquid at the mechanical seal of the liquid ring vacuum pump and avoiding the leakage of the leaked liquid to pollute the environment.

[0008] In the above liquid recovery structure of a liquid ring vacuum pump based on mechanical seals, a liquid inlet pipe extending out of the pump body is connected to the liquid inlet of the pump body. The first liquid return pipe and the second liquid return pipe are respectively connected to the side wall of the part where the liquid inlet pipe extends out of the pump body. A plug is detachably arranged at the end of the liquid inlet pipe extending out of the pump body. When the liquid ring vacuum pump stops running, after opening the plug, the liquid inlet pipe can be used as a drain pipe, serving multiple purposes, and facilitating the cleaning of the interior of the chamber when disassembling and assembling the liquid ring vacuum pump.

[0009] In the above liquid recovery structure of a liquid ring vacuum pump based on mechanical seals, a PLC controller is arranged on the pump body. A liquid level sensor is arranged in each chamber. A first solenoid valve and a second solenoid valve for controlling on-off are respectively arranged on the first liquid return pipe and the second liquid return pipe. The liquid level sensor, the first solenoid valve and the second solenoid valve are respectively electrically connected to the PLC controller, and the PLC controller can respectively control the opening and closing of the first solenoid valve and the second solenoid valve according to the detection signals of the corresponding liquid level sensors. By using the liquid level sensor to monitor the liquid level in the chamber in real time, when the liquid level in the chamber is higher than the set threshold, the PLC controller controls the opening of the first solenoid valve or the second solenoid valve corresponding to this chamber to discharge the liquid in this chamber into the pump body for recycling. When the liquid level in this chamber drops back to the set threshold, the PLC controller controls the closing of the first solenoid valve or the second solenoid valve corresponding to this chamber, automatically realizing the dynamic balance of the liquid volume in the chamber. That is, through the linkage between the liquid level sensor, the first solenoid valve, the second solenoid valve and the PLC controller, the whole process automation of the "collection - filtration - circulation" closed-loop recovery of the leaked liquid at the mechanical seal of the liquid ring vacuum pump is realized, reducing manual intervention, which is beneficial to improving production efficiency (reducing the shutdown frequency) and ensuring the safety of operators in a continuous and toxic and harmful chemical production environment.

[0010] In the above liquid recovery structure based on mechanical seal of a liquid ring vacuum pump, a first filter and a second filter are respectively arranged on the first liquid return pipe and the second liquid return pipe. The first filter is located between the liquid inlet of the pump body and the first solenoid valve, and the second filter is located between the liquid inlet of the pump body and the second solenoid valve. The first filter and the second filter can remove impurities and particulate matters in the leaked liquid, ensure the cleanliness of the liquid recovered through this liquid recovery structure, protect the internal components of the pump body (such as mechanical seal components, impellers, etc.) from wear, extend the service life and reliability of the liquid ring vacuum pump, reduce the frequency of shutdown maintenance. At the same time, the first filter and the second filter are closer to the liquid inlet of the pump body, ensuring that the recovered liquid entering the liquid inlet of the pump body is filtered, and better ensuring the cleanliness of the liquid recovered through this liquid recovery structure.

[0011] In the above liquid recovery structure based on mechanical seal of a liquid ring vacuum pump, viewing windows for observing the internal situation are respectively arranged on the two end covers. By arranging the viewing windows, it is convenient for the operator to directly observe the situation in the two chambers, ensuring the normal operation of the liquid recovery structure.

[0012] In the above liquid recovery structure based on mechanical seal of a liquid ring vacuum pump, an annular mounting portion is provided on the inner peripheral wall of the end cover. An oil seal is connected to the annular mounting portion. The oil seal is sleeved on the rotating shaft and forms a sealed abutment with the rotating shaft. The oil seal divides the chamber into an oil storage chamber and a liquid storage chamber. The oil storage chamber is filled with lubricating oil. A bearing located in the oil storage chamber is arranged between the rotating shaft and the end cover. The first liquid return pipe and the second liquid return pipe are both connected to the liquid storage chamber. By using the oil seal to divide the chamber into an oil storage chamber and a liquid storage chamber, and arranging a bearing in the oil storage chamber filled with lubricating oil to support the rotating shaft and reduce the friction between the rotating shaft and the mechanical seal component (the lubricating oil in the oil storage chamber will not enter the liquid storage chamber under the blockage of the oil seal), the service life and reliability of the liquid ring vacuum pump are extended.

[0013] Compared with the prior art, the advantages of the liquid recovery structure based on mechanical seal of this liquid ring vacuum pump are as follows: The liquid recovery structure based on mechanical seal of this liquid ring vacuum pump forms a closed chamber by arranging end covers at the mechanical seal leakage points at both ends of the rotating shaft to physically isolate the contact between the leaked liquid and the environment and centrally collect the leaked liquid. At the same time, two independent first liquid return pipes and second liquid return pipes are arranged to connect the two chambers to the liquid inlet of the pump body respectively. Thus, using the negative pressure suction at the liquid inlet of the pump body as the driving force, without an additional power device, the leaked liquid in the two chambers is actively sucked back into the pump body, realizing a closed-loop circulation circuit for the leaked liquid, and thus realizing the recovery and utilization of the leaked liquid at the mechanical seal of the liquid ring vacuum pump, and avoiding the leakage of the leaked liquid to pollute the environment. Description of the Drawings

[0014] Figure 1 It is one of the three-dimensional structure schematic diagrams of the liquid recovery structure of the present liquid ring vacuum pump based on mechanical seal.

[0015] Figure 2 It is the second three-dimensional structure schematic diagram of the liquid recovery structure of the present liquid ring vacuum pump based on mechanical seal.

[0016] Figure 3 It is a cross-sectional view of the liquid recovery structure of the present liquid ring vacuum pump based on mechanical seal.

[0017] Figure 4 It is Figure 3 a partial enlarged view of the position A in

[0018] In the figure, 1 is the pump body; 1a is the liquid inlet; 2 is the rotating shaft; 3 is the mechanical seal assembly; 4 is the end cover; 4a is the annular mounting part; 5 is the chamber; 5a is the oil storage chamber; 5b is the liquid storage chamber; 6 is the first liquid return pipe; 7 is the second liquid return pipe; 8 is the liquid inlet pipe; 9 is the plug; 10 is the liquid level sensor; 11 is the first solenoid valve; 12 is the second solenoid valve; 13 is the first filter; 14 is the second filter; 15 is the window; 16 is the oil seal; 17 is the bearing. Detailed implementation mode

[0019] The following are specific embodiments of the present invention and in combination with the attached drawings, the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments.

[0020] A liquid recovery structure of a liquid ring vacuum pump based on mechanical seal, referring to Figures 1-4 , the liquid ring vacuum pump includes a pump body 1 and a rotating shaft 2 rotatably arranged in the pump body 1. Mechanical seal assemblies 3 are respectively arranged between the two ends of the rotating shaft 2 and the pump body 1. The present liquid recovery structure includes two end covers 4 respectively sleeved on the two end portions of the rotating shaft 2 and connected to the pump body 1. A closed chamber 5 containing the mechanical seal assembly 3 is formed between the end cover 4 and the pump body 1. The two chambers 5 are respectively communicated with the liquid inlet 1a of the pump body 1 through a first liquid return pipe 6 and a second liquid return pipe 7.

[0021] Referring to Figure 3 and Figure 4 , specifically, an annular mounting part 4a is provided on the inner peripheral wall of the end cover 4. An oil seal 16 is connected to the annular mounting part 4a. The oil seal 16 is sleeved on the rotating shaft 2 and forms a sealing abutment with the rotating shaft 2. The oil seal 16 divides the chamber 5 into an oil storage chamber 5a and a liquid storage chamber 5b. Lubricating oil is contained in the oil storage chamber 5a. A bearing 17 located in the oil storage chamber 5a is arranged between the rotating shaft 2 and the end cover 4. The first liquid return pipe 6 and the second liquid return pipe 7 are both connected to the liquid storage chamber 5b.

[0022] Reference Figure 1 and Figure 3 Furthermore, a liquid inlet pipe 8 extending out of the pump body 1 is connected to the liquid inlet 1a of the pump body 1. The first liquid return pipe 6 and the second liquid return pipe 7 are respectively connected to the side wall of the part where the liquid inlet pipe 8 extends out of the pump body 1. A plug 9 is detachably arranged at the end of the liquid inlet pipe 8 extending out of the pump body 1.

[0023] Reference Figure 1 、 Figure 2 and Figure 3 Furthermore, a PLC controller (not shown in the figure, the PLC controller in this embodiment can adopt an existing controller, generally as long as it has the function of collecting the signals of the liquid level sensors and controlling the opening / closing of the solenoid valves) is arranged on the pump body 1. A liquid level sensor 10 is arranged in each chamber 5. A first solenoid valve 11 and a second solenoid valve 12 for controlling the on / off are respectively arranged on the first liquid return pipe 6 and the second liquid return pipe 7. The liquid level sensor 10, the first solenoid valve 11 and the second solenoid valve 12 are respectively electrically connected to the PLC controller, and the PLC controller can respectively control the opening and closing of the first solenoid valve 11 and the second solenoid valve 12 according to the detection signals of the corresponding liquid level sensors 10.

[0024] Reference Figure 1 、 Figure 2 and Figure 3 Furthermore, a first filter 13 and a second filter 14 are respectively arranged on the first liquid return pipe 6 and the second liquid return pipe 7. The first filter 13 is located between the liquid inlet 1a of the pump body 1 and the first solenoid valve 11, and the second filter 14 is located between the liquid inlet 1a of the pump body 1 and the second solenoid valve 12.

[0025] In this embodiment, it is preferably that viewing windows 15 for observing the internal situation are respectively arranged on the two end covers 4.

[0026] When the liquid ring vacuum pump is in operation, the pressure at its liquid inlet 1a is lower than the atmospheric pressure, forming a negative pressure state. The liquid recovery structure of this liquid ring vacuum pump based on mechanical seals forms a closed chamber 5 by setting end caps 4 at the mechanical seal leakage points at both ends of the rotating shaft 2 to physically isolate the contact between the leaked liquid and the environment and centrally collect the leaked liquid. At the same time, two independent first liquid return pipes 6 and second liquid return pipes 7 are set to connect the two chambers 5 to the liquid inlet 1a of the pump body 1 respectively. Thus, using the negative pressure suction at the liquid inlet 1a of the pump body 1 as the driving force and without an additional power device, the leaked liquid in the two chambers 5 is actively sucked back into the pump body 1, realizing a closed-loop circulation circuit for the leaked liquid, thereby realizing the recovery and utilization of the leaked liquid at the mechanical seal of the liquid ring vacuum pump, achieving "zero escape" of the leaked liquid, avoiding environmental pollution caused by the leakage of the leaked liquid. Through the redundant design of the double pipelines of the first liquid return pipe 6 and the second liquid return pipe 7, the reliability of the use of this liquid recovery structure is improved. At the same time, using the negative pressure suction at the liquid inlet 1a of the pump body 1 as the driving force is energy-saving and efficient, and the liquid recovery rate is increased by more than 30%.

[0027] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A liquid recovery structure based on mechanical seals for a liquid ring vacuum pump. The liquid ring vacuum pump includes a pump body (1) and a rotating shaft (2) rotatably disposed within the pump body (1). Mechanical seal assemblies (3) are respectively provided between both ends of the rotating shaft (2) and the pump body (1). It is characterized in that, This liquid recovery structure includes two end caps (4) respectively covering the two ends of the rotating shaft (2) and connected to the pump body (1). A chamber (5) that is airtight and houses the mechanical seal assembly (3) is formed between the end cap (4) and the pump body (1). The two chambers (5) are respectively connected to the liquid inlet (1a) of the pump body (1) through a first liquid return pipe (6) and a second liquid return pipe (7).

2. The liquid recovery structure based on mechanical seal of a liquid ring vacuum pump according to claim 1, characterized in that A liquid inlet pipe (8) extending out of the pump body (1) is connected to the liquid inlet (1a) of the pump body (1). The first liquid return pipe (6) and the second liquid return pipe (7) are respectively connected to the side wall of the part where the liquid inlet pipe (8) extends out of the pump body (1). A plug (9) is detachably arranged at the end of the liquid inlet pipe (8) extending out of the pump body (1).

3. A liquid recovery structure based on mechanical seal of a liquid ring vacuum pump according to claim 1 or 2, characterized in that, A PLC controller is arranged on the pump body (1). A liquid level sensor (10) is arranged in each chamber (5). A first electromagnetic valve (11) and a second electromagnetic valve (12) for controlling on / off are respectively arranged on the first liquid return pipe (6) and the second liquid return pipe (7). The liquid level sensor (10), the first electromagnetic valve (11) and the second electromagnetic valve (12) are respectively electrically connected to the PLC controller, and the PLC controller can respectively control the opening and closing of the first electromagnetic valve (11) and the second electromagnetic valve (12) according to the detection signals of the corresponding liquid level sensors (10).

4. A liquid recovery structure based on mechanical seal for a liquid ring vacuum pump according to claim 3, characterized in that, A first filter (13) and a second filter (14) are respectively arranged on the first liquid return pipe (6) and the second liquid return pipe (7). The first filter (13) is located between the liquid inlet (1a) of the pump body (1) and the first electromagnetic valve (11), and the second filter (14) is located between the liquid inlet (1a) of the pump body (1) and the second electromagnetic valve (12).

5. A liquid recovery structure based on mechanical seal for a liquid ring vacuum pump according to claim 3, characterized in that, Viewing windows (15) for observing the internal situation are respectively arranged on the two end caps (4).

6. A liquid recovery structure based on mechanical seal for a liquid ring vacuum pump according to claim 3, characterized in that, An annular mounting part (4a) is provided on the inner peripheral wall of the end cap (4). An oil seal (16) is connected to the annular mounting part (4a). The oil seal (16) is sleeved on the rotating shaft (2) and forms a sealing abutment with the rotating shaft (2). The oil seal (16) divides the chamber (5) into an oil storage chamber (5a) and a liquid storage chamber (5b). Lubricating oil is contained in the oil storage chamber (5a). A bearing (17) located in the oil storage chamber (5a) is arranged between the rotating shaft (2) and the end cap (4). The first liquid return pipe (6) and the second liquid return pipe (7) are both connected to the liquid storage chamber (5b).

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