Energy-saving centrifugal pump

Abstract

FIELD: pumps.SUBSTANCE: present invention relates to a centrifugal pump, and more particularly to an energy-saving centrifugal pump in which a dynamic seal and a shut-off seal are located inside and outside the pump body, respectively. The dynamic seal includes an auxiliary vane located on the reverse side of the impeller, an expeller chamber located on the rear side of the impeller and mounted on the pump body, and an expeller located in the expeller chamber and connected to the sleeve. The shut-off seal is located on the rear side of the pump cover and includes a stationary ring put on the sleeve and mounted on the pump cover, a dynamic ring put on the sleeve and located on the rear side of the stationary ring, and a traction block; the dynamic ring has a metal bellows design, one end of which is remote from the stationary ring secured on the sleeve, and the other end is free; the traction block is connected to both ends of the dynamic ring respectively; when disconnected, the sealing surfaces of the dynamic ring and the stationary ring are in close contact, and during operation, the centrifugal force created by the traction block pulls the free end of the dynamic ring from the stationary ring.EFFECT: centrifugal pump requires little maintenance, has low mechanical energy losses, does not require the use of a buffer liquid for the mechanical seal and is highly durable when handling media prone to crystallization / scaling.10 cl, 3 dwg

Description

[0001] Field of technology to which the invention relates

[0002] The present invention relates to a centrifugal pump, and more particularly, to an energy-saving centrifugal pump.

[0003] State of the art

[0004] Centrifugal pumps are commonly used in chemical, metallurgy, and environmental protection industries for transporting liquid media. Problems such as frequent shaft seal burnout, high maintenance rate due to leakage, low pump efficiency, large mechanical energy loss, and high energy consumption due to the use of buffer liquid for mechanical seals have always troubled practitioners. Especially if the medium itself is easily crystallized, contains solid particles, or has a high temperature (>150°C), it can easily damage the shaft seal, resulting in large-scale leakage of the process medium, affecting the stability of the process system, safety, and environmental protection. Specifically:

[0005] 1) If a gland seal is used as a shaft seal, despite its low cost, simple design, easy installation and maintenance, it has a short service life, a high leakage rate, in addition, the gland and sleeve can wear out, which will not only lead to additional losses of mechanical energy, but also increase the likelihood of leakage;

[0006] 2) If a single mechanical seal is used as a shaft seal, although its sealing performance is better than that of a gland seal, for a medium containing solid particles, these solid particles are easy to enter the sealing surface between the dynamic and stationary rings, causing uneven wear of the sealing surface to the point of damage, resulting in a reduction in service life, the single mechanical seal is in a semi-liquid friction state during operation, and there is also a certain loss of mechanical energy, but less than that of a gland seal;

[0007] 3) If a double mechanical seal is used as a shaft seal, although its sealing properties are better than that of a single mechanical seal, it requires additional buffer fluid, has a high energy consumption, and has high requirements for the purity and pressure of the buffer fluid; in addition, there is a risk of buffer fluid leakage into the process medium. The double mechanical seal is also in a semi-liquid friction state during operation, and a certain loss of mechanical energy also occurs, but it is less than that of a gland seal and greater than that of a single mechanical seal;

[0008] 4) If the shaft seal adopts dynamic seal, although it can ensure effective sealing during pump operation, severe leakage of medium may occur when the pump stops;

[0009] 5) If the shaft seal is a combination of dynamic seal and shut-off seal, the shut-off seal is generally made up of gland seal, spiral seal, spring seal, etc., whose sealing performance is often poor, especially if the process medium is prone to crystallization and scaling, which can easily lead to the failure of the shut-off seal.

[0010] Therefore, modern centrifugal pumps urgently need to solve problems such as frequent shaft seal maintenance, large mechanical energy losses, high energy consumption of buffer liquid, and low resistance to media prone to crystallization / scaling.

[0011] The essence of the invention

[0012] The purpose of the present invention is to provide an energy-saving centrifugal pump, which centrifugal pump is low in maintenance, has low mechanical energy loss, does not require the use of a buffer liquid for the mechanical seal, and has high strength when working with a medium prone to crystallization / scaling.

[0013] In a first aspect, the present invention provides an energy-saving centrifugal pump, which includes a pump body, wherein the pump body has an inlet at the front end, an outlet at the side and a pump cover installed at the rear end, a pump shaft with an external drive and a sleeve on the pump shaft passing through the pump cover and entering the pump body, and an impeller having a guide flow channel installed on the front end of the pump shaft; a dynamic seal and a shut-off seal are located inside and outside the pump body, respectively; the dynamic seal includes an auxiliary vane located on the rear side of the impeller, an expeller chamber located on the rear side of the impeller and mounted on the pump body, and an expeller located in the expeller chamber and connected to the sleeve;the shut-off seal is located on the rear side of the pump cover and includes a stationary ring put on the sleeve and mounted on the pump cover, a dynamic ring put on the sleeve and located on the rear side of the stationary ring, and a traction block; the dynamic ring has a metal bellows structure, one end of which is remote from the stationary ring fixed on the sleeve, and the other end is free; the traction block is connected to both ends of the dynamic ring separately, when disconnected, the sealing surfaces of the dynamic ring and the stationary ring are in close contact, during operation, the centrifugal force generated by the traction block pulls the free end of the dynamic ring away from the stationary ring.

[0014] In one embodiment, one end of the traction block is pivotally attached to the end of the dynamic ring remote from the stationary ring, and the other end is connected to the free end of the dynamic ring by a traction cable or pivotally attached to the free end of the dynamic ring by a traction rod.

[0015] In another embodiment, the stationary ring is mounted on the rear side of the pump cover using a stationary ring sealing gasket and a stationary ring screw, the end of the dynamic ring remote from the stationary ring is fixed to the mounting ring using the dynamic ring screw, and the mounting ring is mounted on the sleeve.

[0016] In another embodiment, at least two dynamic rings rotate around the traction unit.

[0017] In another embodiment, one, two or more groups of dynamic seals are installed; one, two or more groups of locking seals are installed.

[0018] In another embodiment, the pump also includes a sealed cover and a purging device, the sealed cover encloses and seals the shut-off seal and the pump shaft and sleeve connected thereto, and the purging device allows the shut-off seal to be purged from the pump shaft and sleeve connected thereto in the sealed cover.

[0019] In another embodiment, steam, clean water, compressed air, or nitrogen is used for purging in the purging device.

[0020] In another embodiment, the pump also includes a sealed cover and a protective device, the sealed cover encloses and seals the shut-off seal and the pump shaft and sleeve connected thereto, and the protective device allows a protective medium of a certain pressure to be pumped into the sealed cover.

[0021] In another embodiment, the protective device has monitoring and warning functions, and when the pressure in the sealed cover is detected to exceed a certain value under the action of the pressure of the medium in the protective device, the process medium is protected from leakage, and a warning signal is issued locally and remotely.

[0022] In another embodiment, the pump also includes a thermal jacket for heating the medium in the pump before starting it, the thermal jacket covers the pump body and the pump cover, a thermal insulating medium is introduced into the thermal jacket or a heating element is placed inside it.

[0023] The beneficial effects of the present invention are:

[0024] This centrifugal pump has the advantages of low maintenance, low mechanical energy loss, no need to use buffer liquid for mechanical seal, and high strength when handling the medium prone to crystallization / scaling, while the dynamic seal ensures sealing during operation: during operation, the auxiliary vane can reduce the pressure of the impeller rear part to keep the axial force of the pump in a balanced state; at the same time, the expeller rotates in the expeller chamber to form a negative pressure zone, so that the medium in the pump does not leak along the pump shaft through the expeller chamber and the expeller, this also prevents the rear side parts of the expeller from being damaged by corrosive, high temperature and solids-containing media;In addition, the centrifugal force generated by the traction unit pulls the free end of the dynamic ring away from the stationary ring, and there will be no problem of wear of the sealing surface and loss of mechanical energy between them; the shut-off seal ensures sealing when disconnected: when disconnected, the sealing surfaces of the dynamic ring and the stationary ring fit tightly against each other, thereby ensuring the sealing of the connection; At the same time, the dynamic ring adopts a metal bellows structure, which is resistant to high temperature, has good wear resistance of the end surface, large bearing capacity and stable operation, and the elastic metal ring parts inside it form a labyrinth seal, thereby preventing wear and corrosion of the sleeve and shaft medium of the pump; there is no need to install a sealing ring, which solves the problem of wear and failure of the sealing ring under high temperature conditions (>150 °C);No buffer fluid is required for the mechanical seal, which reduces frictional resistance. It has good traceability and seismic resistance, as well as high resistance to vibration and pump shaft deflection. This centrifugal pump is highly durable when handling hazardous media that easily crystallize, form scale, solidify at room temperature, are flammable, explosive, etc., and is widely used in the chemical, metallurgical, and environmental protection industries for transporting liquid media.

[0025] Contents of the attached figures

[0026] Fig. 1 shows a structural diagram of an energy-saving and maintenance-free centrifugal pump provided by an embodiment of the present invention.

[0027] Fig. 2 is a diagram showing a shut-off seal provided by an embodiment of the present invention when shutting off.

[0028] Fig. 3 is a diagram showing a shut-off seal provided by an embodiment of the present invention during operation.

[0029] In the figure: 1-pump casing; 2-impeller; 3-pump cover; 4-pump shaft; 5-sleeve; 6-bearing; 7-thermal cover; 8-sealed cover; 9-blow-off device; 10-protective device; 11-auxiliary vane; 12-expeller chamber; 13-expeller; 14-stationary ring screw; 15-stationary ring; 16-stationary ring sealing gasket; 17-dynamic ring screw; 18-dynamic ring; 19-traction rod; 20-traction block.

[0030] Specific methods of implementation

[0031] The present invention is described in more detail below together with the accompanying figures and embodiments.

[0032] As shown in Fig. 1-3, the energy-saving centrifugal pump includes a pump body 1, wherein the pump body 1 has an inlet at a front end, an outlet at the side and a pump cover 3 installed at a rear end, a pump shaft 4 with an external drive and a sleeve 5 on the pump shaft 4 passing through the pump cover 3 and entering the pump body 1, and an impeller 2 having a guide flow channel installed on the front end of the pump shaft 4; a dynamic seal and a shut-off seal are disposed inside and outside the pump body 1, respectively; the dynamic seal includes an auxiliary vane 11 located on the back side of the impeller 2, an expeller chamber 12 located on the rear side of the impeller 2 and mounted on the pump body 1, and an expeller 13 located in the expeller chamber 12 and connected to the sleeve 5;the shut-off seal is located on the rear side of the cover 3 of the pump and includes a stationary ring 15 put on the sleeve 5 and mounted on the cover of the pump 3, a dynamic ring 18 put on the sleeve 5 and located on the rear side of the stationary ring 15, and a traction block 20; the dynamic ring 18 has a design of a metal bellows, one end of which is remote from the stationary ring 15, fixed on the sleeve 5, and the other end is free; the traction block 20 is connected to both ends of the dynamic ring 18 separately, when disconnected, the sealing surfaces of the dynamic ring 18 and the stationary ring 15 are in close contact, during operation, the centrifugal force created by the traction block 20 pulls the free end of the dynamic ring 18 from the stationary ring 15.

[0033] This centrifugal pump has the advantages of low maintenance, low mechanical energy loss, no need for the use of buffer liquid for the mechanical seal, and high strength when handling the medium prone to crystallization / scaling; Meanwhile, the dynamic seal ensures sealing during operation: during operation, the auxiliary vane 11 can reduce the pressure of the rear of the impeller 2, so as to maintain the axial force of the pump in a balanced state; at the same time, the expeller 13 rotates in the expeller chamber 12, forming a negative pressure zone, so that the medium in the pump does not leak along the pump shaft 4 through the expeller chamber 12 and the expeller 13, this also prevents the rear side parts of the expeller 13 from being damaged by corrosive, high-temperature and solid-containing media;In addition, the centrifugal force generated by the traction unit 20 pulls the free end of the dynamic ring 18 away from the stationary ring 15, and there will be no problem of wear of the sealing surface and loss of mechanical energy between them; the shut-off seal ensures sealing when disconnected: when disconnected, the sealing surfaces of the dynamic ring 18 and the stationary ring 15 fit tightly against each other, thereby ensuring the sealing of the connection; at the same time, the dynamic ring 18 has a metal bellows structure, which is resistant to high temperatures, has good wear resistance of the end surface, large load-bearing capacity and stable operation, and the elastic metal ring parts inside it form a labyrinth seal, thereby preventing wear and corrosion of the medium of the sleeve 5 and the shaft 4 of the pump;There is no need to install an O-ring, which solves the problem of wear and failure of the O-ring under high temperature conditions >150°C; no need for a buffer liquid for the mechanical seal, which reduces friction resistance, has good trace resistance and seismic resistance, has high resistance to vibration and deflection of the pump shaft 4. This centrifugal pump has high strength when working with hazardous media that are easily crystallized, form scale, solidify at room temperature, are flammable, explosive, etc., and can be widely used in the chemical, metallurgy and environmental protection industries for transporting liquid media.

[0034] As shown in Fig. 1-3, in the present embodiment, one end of the traction block 20 is pivotally attached to the end of the dynamic ring 18 away from the stationary ring 15, and the other end is connected to the free end of the dynamic ring 18 by a traction cable or pivotally attached to the free end of the dynamic ring 18 by a traction rod 19. During operation, the centrifugal force generated by the traction block 20 causes the side close to the free end of the dynamic ring 18 to swing in a direction opposite to the radial one, thereby pulling the free end of the dynamic ring 18 away from the stationary ring 15 by means of a traction cable or traction rod 19.The weight, dimensions and shape of the traction unit 20 are designed and calculated based on the traction force required to pull the free end of the dynamic ring 18 and the force transmission path, ensuring that the free end of the dynamic ring 18 can be pulled without excessive compression of the dynamic ring 18 when a certain rotation speed is exceeded.

[0035] As shown in Fig. 1-3, in the present embodiment, the stationary ring 15 is mounted on the rear side of the pump cover 3 by a stationary ring sealing gasket 16 and a stationary ring screw 14, the end of the dynamic ring 18 distant from the stationary ring 15 is fixed to the mounting ring by a dynamic ring screw 17, and the mounting ring is mounted on the sleeve 5; the installation method of the stationary ring 15 and the dynamic ring 18 is simple and reliable.

[0036] As shown in Fig. 1-3, in the present embodiment, at least two dynamic rings 18 rotate around the traction block 20, and during operation, the free ends of the dynamic rings 18 are uniformly pulled away from the stationary ring 15.

[0037] One, two or more groups of dynamic seals can be installed; one, two or more groups of locking seals can also be installed. In general, the number of groups is selected according to the sealing needs and is not limited to a certain number.

[0038] As shown in Fig. 1, in the present embodiment, the rear end of the pump shaft 4 passes through the bearing 6 and is externally connected to the drive.

[0039] As shown in Fig. 1, in the present embodiment, the pump also includes a sealed cover 8 and a blowing device 9, the sealed cover 8 encloses and seals the locking seal and the pump shaft 4 and the sleeve 5 connected thereto, and the blowing device 9 allows the locking seal and the pump shaft 4 and the sleeve 5 connected thereto to be blown out in the sealed cover 8; steam, clean water, compressed air or nitrogen are used for blowing in the blowing device 9.With respect to the medium that easily crystallizes, forms scale, becomes viscous or even solid at room temperature, a sealed medium formed by a sealed cover 8 and a purging function of a purging device 9 are used, before starting the pump, the shut-off seal and the pump shaft 4 and sleeve 5 connected thereto are purged to ensure that the subsequent movement of the dynamic ring 18 will not be limited by the medium, when shutting down, the shut-off seal and the pump shaft 4 and sleeve 5 connected thereto are purged to ensure the cleanliness and tightness of the sealing surfaces of the stationary ring 15 and the dynamic ring 18.The blowing device 9 has a conventional structure, which includes a pipeline, nozzles, valves, injection pumps, steam / water supply sources; the injection pump supplies the medium from the water supply source through the pipeline to the spray nozzle, or the high-pressure steam generated by the steam source enters the nozzle through the pipeline and is sprayed; the valves control the opening and closing of the pipelines as well as the flow of liquid.

[0040] As shown in Fig. 1, in the present embodiment, the pump also includes a sealed cover 8 and a protective device 10, the sealed cover 8 encloses and seals the shut-off seal and the pump shaft 4 and sleeve 5 connected thereto, and the protective device 10 allows a protective medium of a certain pressure to be injected into the sealed cover 8. In the case of using a hazardous medium such as a high-temperature, toxic, flammable or explosive medium, etc., when the seal fails, a protective medium under a certain pressure is injected into the sealed cover 8 through the protective device 10, and the pressure effect can be used to prevent leakage of the medium.The protective device 10 has a conventional emergency protection design, which may be a nitrogen protective device, a membrane protective device for storing energy under pressure, a white oil protective device, or a conventional protective device for storing energy under pressure. The protective device 10 has monitoring and warning functions. When the pressure in the sealed cover 8 exceeds a certain value, the pressure of the medium in the protective device 10 protects the process medium from leaks, and a warning signal is generated locally and remotely.

[0041] As shown in Fig. 1, in the present embodiment, the pump also includes a thermal jacket 7 for heating the medium in the pump before its start. The thermal jacket 7 covers the pump body 1 and the pump cover 3, and a heat-insulating medium is introduced into the thermal jacket 7 or a heating element is placed inside it. In the case of using a medium that easily crystallizes, forms scale, becomes viscous, or even solid at room temperature, the thermal jacket 7 heats the medium in the pump before its start, which makes it possible to avoid the cranking step before start-up and damage the internal structural parts of the pump body 1 by solid particles. Steam, superheated water, heat-conducting oil, etc. can be used as the heat-insulating medium, and the heating element can be a heating wire, a heating plate, etc.

[0042] It should be understood that those skilled in the art can make improvements and modifications based on the above description, and all such improvements and modifications are included within the scope of protection of the appended claims of the present invention.

Claims

1. An energy-saving centrifugal pump that includes a pump housing (1), wherein the pump housing (1) has an inlet at the front end, an outlet at the side and a pump cover (3) mounted at the rear end, a pump shaft (4) with an external drive and a sleeve (5) on the pump shaft (4) passing through the pump cover (3) and entering the pump housing (1), and an impeller (2) having a guide flow channel mounted on the front end of the pump shaft (4), characterized in that a dynamic seal and a shut-off seal are located inside and outside the pump housing (1), respectively; the dynamic seal includes an auxiliary blade (11) located on the rear side of the impeller (2), an expeller chamber (12) located on the rear side of the impeller (2) and mounted on the pump housing (1), and an expeller (13) located in the expeller chamber (12) and connected to the sleeve (5);the shut-off seal is located on the rear side of the cover (3) of the pump and includes a stationary ring (15) put on the sleeve (5) and mounted on the cover (3) of the pump, a dynamic ring (18) put on the sleeve (5) and located on the rear side of the stationary ring (15), and a traction block (20); the dynamic ring (18) has a metal bellows design, one end of which is remote from the stationary ring (15), fixed on the sleeve (5), and the other end is free; the traction block (20) is connected to both ends of the dynamic ring (18) separately, when disconnected, the sealing surfaces of the dynamic ring (18) and the stationary ring (15) are in close contact, during operation, the centrifugal force created by the traction block (20) pulls the free end of the dynamic ring (18) from the stationary ring (15).; 2. The pump according to claim 1, characterized in that one end of the traction block (20) is pivotally attached to the end of the dynamic ring (18), remote from the stationary ring (15), and the other end is connected to the free end of the dynamic ring (18) using a traction cable or pivotally attached to the free end of the dynamic ring (18) using a traction rod (19).

3. The pump according to claim 1, characterized in that the stationary ring (15) is installed on the rear side of the cover (3) of the pump using a sealing gasket (16) of the stationary ring and a screw (14) of the stationary ring, the end of the dynamic ring (18), remote from the stationary ring (15), is secured to the mounting ring using a screw (17) of the dynamic ring, and the mounting ring is installed on the sleeve (5).

4. The pump according to item 1, characterized in that at least two dynamic rings (18) rotate around the traction block (20).

5. The pump according to paragraph 1, characterized in that one, two or more groups of dynamic seals are installed; one, two or more groups of shut-off seals are installed.

6. A pump according to any one of paragraphs 1-5, characterized in that it also includes a sealed cover (8) and a blow-off device (9), the sealed cover (8) encloses and seals the shut-off seal and the pump shaft (4) and sleeve (5) connected to it, and the blow-off device (9) allows blowing the shut-off seal and the pump shaft (4) and sleeve (5) connected to it in the sealed cover (8).

7. A pump according to item 6, characterized in that steam, clean water, compressed air or nitrogen is used for blowing in the blowing device (9).

8. A pump according to any one of paragraphs 1-5, characterized in that it also includes a sealed cover (8) and a protective device (10), the sealed cover (8) encloses and seals the shut-off seal and the shaft (4) of the pump and the sleeve (5) connected to it, and the protective device (10) allows for the injection of a protective medium of a certain pressure into the sealed cover (8).

9. The pump according to item 8, characterized in that the protective device (10) has monitoring and warning functions; when a certain pressure value in the sealed cover (8) is detected to be exceeded, under the influence of the pressure of the medium in the protective device (10), the process medium is protected from leaks, and a warning signal is sent locally and remotely.

10. A pump according to any one of paragraphs 1-5, characterized in that it also includes a thermal jacket (7) for heating the medium in the pump before starting it, the thermal jacket (7) covers the pump body (1) and the pump cover (3), a heat-insulating medium is introduced into the thermal jacket (7) or a heating element is placed inside it.

Images