Double-mechanical-seal pipeline centrifugal pump

Abstract

The utility model provides a double-mechanical-seal pipeline centrifugal pump, which belongs to the technical field of centrifugal pumps and comprises a pump body, a pump cover, a pump shaft, an impeller, a motor, a siphon tank, a siphon and a liquid return pipe. An oil cavity is formed in the pump cover, a first through hole and a second through hole are oppositely formed in the side wall of the oil cavity, and the middle of the pump shaft penetrates through the first through hole, the oil cavity and the second through hole. A mechanical seal is arranged between the pump shaft and the first through hole, and a sealing assembly is arranged between the pump shaft and the second through hole. The oil cavity and the siphon tank are filled with lubricating oil, the siphon tank is communicated with the oil cavity through a siphon, and the siphon tank is communicated with the oil cavity through a liquid return pipe. After absorbing operation heat, the lubricating oil automatically moves upwards, enters the siphon tank through the siphon tank and then returns to the oil cavity through the liquid return pipe; if the liquid leaks into the oil cavity, the leaked liquid can enter the siphon tank along with the lubricating oil. Whether the liquid leaks to the oil cavity or not can be fed back by observing the liquid in the siphon tank, intervention is conducted in time, and the transportation safety of dangerous liquid such as flammable media is improved.

Description

Technical Field

[0001] This application belongs to the field of centrifugal pump technology, and more specifically, relates to a dual-mechanical-seal pipeline centrifugal pump. Background Technology

[0002] A pipeline centrifugal pump uses the centrifugal force generated by the rotation of an impeller to transport liquids. A pipeline centrifugal pump consists of an impeller, pump body, pump cover, and pump shaft. One end of the pump shaft is connected to the motor, and the other end extends through the pump cover into the pump body, connecting to the impeller inside the pump body. To prevent liquid leakage, a mechanical seal or double seal is installed between the pump shaft and the pump cover.

[0003] In the prior art, Chinese utility model patent CN222228948U discloses a connection structure between the impeller and the motor in a centrifugal pump. In this design, the sealing cover (pump cover) has a cavity, a first through hole, and a second through hole. The pump shaft passes through the first through hole, the cavity, and the second through hole and connects to the internal impeller. A mechanical seal is installed between the first through hole and the pump shaft. Based on this design, it is conceivable that, to improve sealing, a sealing component can also be installed between the second through hole and the pump shaft, achieving double sealing at both the first and second through holes. Liquid would only leak after passing through both seals, thus improving sealing performance.

[0004] However, the implementation of a double seal also presents certain problems. Specifically, when liquid leaks from the pump body, passes through the first seal into the cavity but before passing through the second seal, or when the first seal is damaged and unable to seal, it is impossible to detect from the outside that liquid has entered the cavity in time, making timely intervention impossible to prevent leakage from the second seal. For some hazardous liquids containing flammable media, the inability to intervene in advance in case of potential leakage from the second seal can easily lead to safety risks such as leaks. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this application provides a dual-mechanical-seal pipeline centrifugal pump that can promptly detect when liquid passes through the first seal, allowing for timely intervention and preventing further leakage from the second seal, thus improving safety.

[0006] To achieve the above objectives, the technical solution of this application provides a dual-mechanical-seal pipeline centrifugal pump, including a pump body, a pump cover, a pump shaft, an impeller, and a motor. The pump cover is installed on the pump body, and the impeller is rotatably disposed within the pump body. The pump cover has an oil chamber, and the sidewalls of the oil chamber are provided with a first through hole and a second through hole. One end of the pump shaft is fixedly connected to the impeller, and the other end of the pump shaft is connected to the output end of the motor. The middle part of the pump shaft passes through the first through hole, the oil chamber, and the second through hole. A mechanical seal is provided between the pump shaft and the first through hole, and a sealing assembly is provided between the pump shaft and the second through hole. The pump also includes a siphon tank, a siphon pipe, and a return pipe. Both the oil chamber and the siphon tank are filled with lubricating oil. The siphon pipe and the siphon tank are positioned higher than the oil chamber. The siphon tank is connected to the oil chamber through the siphon pipe, and the bottom of the siphon tank is connected to the oil chamber through the return pipe.

[0007] The heat generated by the pump shaft during operation heats the lubricating oil in the oil chamber. The warmer portion of the lubricating oil rises spontaneously and enters the siphon tank through the siphon pipe, then returns to the oil chamber via the return pipe. If liquid leaks from the pump body through the mechanical seal into the oil chamber, some of the leaked liquid will follow the heated lubricating oil into the siphon tank. Observing the liquid condition in the siphon tank can indicate whether liquid has leaked into the oil chamber. This technical solution can detect leaks at the mechanical seal in a timely manner without interrupting the operation of the dual-mechanical-seal pipeline centrifugal pump, allowing for timely intervention and preventing further leakage of liquid from the sealing components to the outside of the equipment, especially improving the safety of transporting hazardous liquids such as flammable media. At the same time, the lubricating oil in the oil chamber is cooled in the siphon tank, carrying away the heat from the pump shaft. The lubricating oil also flows in a closed loop between the oil chamber, siphon pipe, siphon tank, and return pipe, improving fluidity and enhancing the lubrication and cooling effect on the pump shaft.

[0008] Optionally, the siphon tank is provided with an observation window on its side wall. During use, it is possible to observe through the observation window whether any leaked liquid has mixed with the lubricating oil without opening the siphon tank, thus preventing the leaked liquid from being exposed.

[0009] Optionally, an oil filling valve is provided at the top of the siphon tank, and an oil drain valve is provided at the bottom of the siphon tank. Under normal use, lubricating oil can be added through the oil filling valve and discharged through the oil drain valve, so as to achieve oil replacement without stopping the machine.

[0010] Optionally, it also includes a base plate and a bracket, with the pump body and bracket both fixedly connected to the base plate, and the siphon tank fixedly connected to the top of the bracket. The base plate and bracket connect the siphon tank, pump, siphon pipe, and return pipe into a single structure, forming a complete unit for easy layout.

[0011] Optionally, an end cover is bolted to the end of the pump cover facing the motor. A second through hole is located in the end cover, and the end of the oil chamber facing the motor is open and closed by the end cover. A sealing ring is clamped between the end cover and the oil chamber. The end cover facilitates the assembly of the pump shaft and sealing components. When the end cover is opened, the oil chamber can be fully exposed for cleaning.

[0012] Optionally, the sealing assembly includes a bushing, a mechanical seal ring, a spring, a diaphragm, an O-ring, and abutment screws. The bushing passes through a second through hole and is fitted onto the outside of the pump shaft, with the O-ring clamped between the bushing and the pump shaft. A groove is provided at the end of the end cover facing the oil cavity, and the mechanical seal ring is fitted onto the outside of the bushing and embedded in the groove. A step is provided on the outer wall of the bushing opposite to the mechanical seal ring, and the diaphragm is fitted onto the outside of the bushing and abuts against the step. The spring is fitted onto the outside of the bushing and clamped between the diaphragm and the mechanical seal ring. The abutment screw is located on the side of the end cover away from the oil cavity, and the abutment screw screws from the outside, passes through the bushing, and abuts against the pump shaft. This sealing assembly can be directly installed on the pump shaft and end cover, and then the end cover can be bolted to the pump cover, facilitating the assembly of the sealing assembly with the pump shaft and pump cover.

[0013] Optionally, a positioning pad is also provided. A retaining ring is fitted on the outer wall of the shaft sleeve. The retaining ring is located on the side of the end cover away from the oil cavity. The abutment screw is screwed through the retaining ring and through the shaft sleeve. The positioning pad is used to clamp between the end cover and the retaining ring. The positioning pad is used to compensate for axial positional deviations between the pump shaft, pump cover, and pump body during assembly. After the entire dual-mechanical-seal pipeline centrifugal pump is installed, the axial position of the pump shaft is fixed, and the positioning pad can be removed.

[0014] The advantages of the technical solution in this application compared to the prior art are as follows:

[0015] This dual-mechanical-seal pipeline centrifugal pump can detect leaks at the mechanical seal without interrupting operation, allowing for timely intervention and preventing further leakage of liquid from the sealing components to the outside of the equipment. This is especially beneficial for the safety of transporting hazardous liquids such as flammable media. Simultaneously, the lubricating oil in the oil chamber is cooled within the siphon tank, removing heat from the pump shaft. Furthermore, the lubricating oil flows in a closed loop between the oil chamber, siphon pipe, siphon tank, and return pipe, improving fluidity and enhancing both lubrication and cooling of the pump shaft. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of a dual-mechanical-seal pipeline centrifugal pump;

[0018] Figure 2 This is a sectional view of the internal structure of a dual-mechanical-seal pipeline centrifugal pump.

[0019] Figure 3 for Figure 2 Enlarged view of a portion of point A in the middle.

[0020] Icons: 1. Pump body; 2. Pump cover; 201. Oil chamber; 202. First through hole; 203. Second through hole; 204. End cover; 205. Sealing ring; 206. Settling groove; 3. Pump shaft; 4. Impeller; 5. Motor; 6. Mechanical seal; 7. Sealing assembly; 701. Shaft sleeve; 702. Mechanical seal ring; 703. Spring; 704. Spacer; 705. O-ring seal; 706. Abutment screw; 707. Step; 708. Retaining ring; 801. Siphon tank; 802. Siphon pipe; 803. Return pipe; 804. Observation window; 805. Oil injection valve; 806. Oil discharge valve; 901. Base plate; 902. Bracket; 10. Positioning pad. Detailed Implementation

[0021] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0022] Example:

[0023] This embodiment provides a dual-mechanical-seal pipeline centrifugal pump, based on... Figures 1 to 3 As shown, the pump includes a pump body 1, a pump cover 2, a pump shaft 3, an impeller 4, and a motor 5. The pump cover 2 is installed on the pump body 1. The impeller 4 is rotatably disposed inside the pump body 1. The pump cover 2 has an oil chamber 201, and the sidewalls of the oil chamber 201 are provided with a first through hole 202 and a second through hole 203. One end of the pump shaft 3 is fixedly connected to the impeller 4, and the other end of the pump shaft 3 is connected to the output end of the motor 5. The middle part of the pump shaft 3 passes through the first through hole 202, the oil chamber 201, and the second through hole 203. A mechanical seal 6 is provided between the pump shaft 3 and the first through hole 202, and a sealing assembly 7 is provided between the pump shaft 3 and the second through hole 203. The mechanical seal 6 serves as the first seal to prevent liquid from entering the oil chamber 201, and the sealing assembly 7 serves as the second seal to prevent liquid from leaking to the outside of the dual-mechanical-seal pipeline centrifugal pump.

[0024] Based on the above structure, it also includes a siphon tank 801, a siphon pipe 802, and a return pipe 803. Both the oil chamber 201 and the siphon tank 801 are filled with lubricating oil. The siphon pipe 802 and the siphon tank 801 are positioned higher than the oil chamber 201. The siphon tank 801 is connected to the oil chamber 201 via the siphon pipe 802, and the bottom of the siphon tank 801 is connected to the oil chamber 201 via the return pipe 803. The lubricating oil is used to lubricate the pump shaft 3 during operation. The heat generated by the pump shaft 3 during operation heats the lubricating oil in the oil chamber 201. The hotter portion of the lubricating oil will spontaneously move upward and enter the siphon tank 801 through the siphon pipe 802, carrying away the heat. After cooling in the siphon tank 801, it returns to the oil chamber 201 via the return pipe 803. Natural cooling is sufficient to meet the cooling requirements. Specifically, the height of the connection between the siphon pipe 802 and the oil chamber 201 can be set higher than the height of the connection between the return pipe 803 and the oil chamber 201 to ensure that the heated and rising lubricating oil can smoothly enter the siphon pipe 802. The lubricating oil flows in a closed loop between the oil chamber 201, siphon pipe 802, siphon tank 801, and return pipe 803, which improves fluidity and enhances the lubrication and cooling effect on the pump shaft 3. If liquid leaks through the mechanical seal 6 into the oil chamber 201, some of the leaked liquid will follow the heated lubricating oil into the siphon tank 801. Observing the liquid condition in the siphon tank 801 can indicate whether liquid has leaked into the oil chamber 201. This technical solution can promptly detect leaks at the mechanical seal 6 without interrupting the operation of the dual-mechanical-seal pipeline centrifugal pump, allowing for timely intervention and preventing further leakage of liquid from the sealing assembly 7 to the outside of the entire equipment. This is especially beneficial for improving the safety of transporting hazardous liquids such as flammable media.

[0025] The siphon tank 801 has an observation window 804 on its side wall. During use, it is possible to observe whether any leaked liquid has mixed with the lubricating oil through the observation window 804 without opening the siphon tank 801, thus preventing the leakage of the liquid. Simultaneously, an oil filling valve 805 is located at the top of the siphon tank 801, and an oil drain valve 806 is located at the bottom. Under normal operating conditions, lubricating oil can be added through the oil filling valve 805 and drained through the oil drain valve 806, achieving lubricating oil replacement without stopping the machine.

[0026] Furthermore, it also includes a base plate 901 and a bracket 902. Both the pump body 1 and the bracket 902 are fixedly connected to the base plate 901, specifically through bolts or even welding. The siphon tank 801 is fixedly connected to the top of the bracket 902, specifically through bolts or welding. The base plate 901 and the bracket 902 connect the siphon tank 801, the main body of the pump, the siphon pipe 802, and the return pipe 803 into a single structure, which can be assembled into a whole during production for easy arrangement as a single unit.

[0027] Furthermore, an end cap 204 is bolted to the end of the pump cover 2 facing the motor 5. A second through hole 203 is located in the end cap 204. The end of the oil chamber 201 facing the motor 5 is open and closed by the end cap 204. A sealing ring 205 is held between the end cap 204 and the oil chamber 201. The end cap 204 facilitates the assembly of the pump shaft 3 and the sealing assembly 7. When the end cap 204 is opened, the oil chamber 201 can be fully exposed for cleaning. Specifically, the sealing assembly 7 includes a bushing 701, a mechanical seal ring 702, a spring 703, a septum 704, an O-ring seal 705, and abutment screws 706. The bushing 701 passes through the second through hole 203 and is fitted onto the outside of the pump shaft 3. The O-ring seal 705 is held between the bushing 701 and the pump shaft 3. The end cap 204 facing the oil cavity 201 has a recess 206. The mechanical seal ring 702 is sleeved on the outside of the bushing 701 and embedded in the recess 206. The outer wall of the bushing 701 has a step 707 opposite to the mechanical seal ring 702. The septum 704 is sleeved on the outside of the bushing 701 and abuts against the step 707. The spring 703 is sleeved on the outside of the bushing 701 and clamped between the septum 704 and the mechanical seal ring 702. The abutment screw 706 is located on the side of the end cap 204 away from the oil cavity 201. The abutment screw 706 is screwed from the outside through the bushing 701 and abuts against the pump shaft 3. This sealing assembly 7 can be directly installed on the pump shaft 3 and the end cap 204, and then the end cap 204 is bolted to the pump cover 2, which facilitates the assembly of the sealing assembly 7 with the pump shaft 3 and the pump cover 2. The specific steps are as follows:

[0028] The spacer 704, spring 703, mechanical seal ring 702, and end cap 204 are sequentially arranged from the top ( Figure 3 (As shown in the diagram) The pump shaft 3 is sequentially fitted onto the outer wall of the bushing 701. The O-ring 705 is inserted into the inner side of the bushing 701, and the sealing ring 205 is inserted into the outer side of the end cover 204. Then, the pump shaft 3 is inserted into the bushing 701, and then the pump shaft 3 is extended from the open end of the oil cavity 201 into the oil cavity 201 and through the first through hole 202. The end cover 204 is then bolted to the pump cover 2. Finally, after adjusting the axial position of the pump shaft 3, the abutment screw 706 is screwed from the outside through the bushing 701 and abuts against the pump shaft 3.

[0029] Furthermore, a positioning pad 10 is also provided. A fixing ring 708 is fitted on the outer wall of the bushing 701. The fixing ring 708 is located on the side of the end cover 204 away from the oil cavity 201. The abutment screw 706 is screwed through the fixing ring 708 and the bushing 701. The positioning pad 10 is used to clamp between the end cover 204 and the fixing ring 708. The positioning pad 10 is used to compensate for the axial positional deviation between the pump shaft 3 and the pump cover 2 and pump body 1 during assembly. After the entire double mechanical seal pipeline centrifugal pump is installed, the axial position of the pump shaft 3 is fixed, and the positioning pad 10 can be removed at this time. The fixing ring 708 is fixedly connected to the bushing 701 by the abutment screw 706. The fixing ring 708 is installed after the sealing assembly 7 is connected to the pump shaft 3, and will not affect the assembly of the sealing assembly 7.

[0030] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A dual-mechanical-seal pipeline centrifugal pump, comprising a pump body, a pump cover, a pump shaft, an impeller, and a motor, wherein the pump cover is installed on the pump body, the impeller is rotatably disposed within the pump body, the pump cover has an oil cavity, and the sidewalls of the oil cavity are provided with a first through hole and a second through hole opposite to each other; one end of the pump shaft is fixedly connected to the impeller, the other end of the pump shaft is connected to the output end of the motor, and the middle portion of the pump shaft passes through the first through hole, the oil cavity, and the second through hole; a mechanical seal is provided between the pump shaft and the first through hole, and a sealing assembly is provided between the pump shaft and the second through hole; Its features are: It also includes a siphon can, a siphon tube, and a return pipe. The oil chamber and the siphon can are both filled with lubricating oil. The siphon tube and the siphon can are positioned higher than the oil chamber. The siphon can is connected to the oil chamber through the siphon tube, and the bottom of the siphon can is connected to the oil chamber through the return pipe.

2. The dual-mechanical-seal pipeline centrifugal pump as described in claim 1, characterized in that: The siphon tank has an observation window on its side wall.

3. The dual-mechanical-seal pipeline centrifugal pump as described in claim 1, characterized in that: The siphon tank is equipped with an oil injection valve at the top and an oil discharge valve at the bottom.

4. The dual-mechanical-seal pipeline centrifugal pump as described in claim 1, characterized in that: It also includes a base plate and a bracket, both of which are fixedly connected to the base plate, and the siphon tank is fixedly connected to the top of the bracket.

5. The dual-mechanical-seal pipeline centrifugal pump as described in any one of claims 1 to 4, characterized in that: An end cap is bolted to the end of the pump cover facing the motor. The second through hole is located in the end cap. The end of the oil chamber facing the motor is open and closed by the end cap. A sealing ring is clamped between the end cap and the oil chamber.

6. The dual-mechanical-seal pipeline centrifugal pump as described in claim 5, characterized in that: The sealing assembly includes a bushing, a mechanical seal ring, a spring, a septum, an O-ring, and abutment screws. The bushing passes through the second through hole and is fitted onto the outside of the pump shaft. The O-ring is clamped between the bushing and the pump shaft. The end cap facing the oil cavity has a recessed groove. The mechanical seal ring is fitted onto the outside of the bushing and embedded in the recessed groove. The outer wall of the bushing has a step opposite to the mechanical seal ring. The septum is fitted onto the outside of the bushing and abuts against the step. The spring is fitted onto the outside of the bushing and clamped between the septum and the mechanical seal ring. The abutment screw is located on the side of the end cap away from the oil cavity. The abutment screw is screwed from the outside through the bushing and abuts against the pump shaft.

7. The dual-mechanical-seal pipeline centrifugal pump as described in claim 6, characterized in that: The bushing is also equipped with a positioning pad. A fixing ring is fitted on the outer wall of the bushing. The fixing ring is located on the side of the end cover away from the oil cavity. The abutment screw is screwed through the fixing ring and through the bushing. The positioning pad is used to hold the end cover and the fixing ring together.

Images