WO2024113593A1

WO2024113593A1 - Energy-saving maintenance-free centrifugal pump

Info

Publication number: WO2024113593A1
Application number: PCT/CN2023/086479
Authority: WO
Inventors: 贾鸿雷; 乔军; 张毅; 王耀; 易正鑫; 刘坤
Original assignee: 中冶南方工程技术有限公司
Priority date: 2022-11-30
Filing date: 2023-04-06
Publication date: 2024-06-06
Also published as: CN118110689A

Abstract

Disclosed in the present invention is an energy-saving maintenance-free centrifugal pump. Power sealing members and shutdown sealing members are respectively provided inside and outside a pump body. Each power sealing member comprises an auxiliary blade provided on the back surface of an impeller, an auxiliary impeller chamber located on the rear side of the impeller and mounted on the pump body, and an auxiliary impeller located in the auxiliary impeller chamber and connected to a shaft sleeve. Each shutdown sealing member is located on the rear side of a pump cover, and comprises a static ring sleeved on the shaft sleeve and mounted on the pump cover, a movable ring sleeved on the shaft sleeve and located on the rear side of the static ring, and a traction block. The movable ring is of a metal bellows structure, the end of the movable ring away from the static ring is fixed to the shaft sleeve, and the other end of the movable ring is free. The traction block is separately connected to two ends of the movable ring. During shutdown, sealing surfaces of the movable ring and the static ring are in close contact; and during operation, the free end of the movable ring is pulled to be away from the static ring by means of the centrifugal force generated by the traction block. The centrifugal pump does not need frequent maintenance, has less mechanical energy loss, does not need a mechanical seal spacer fluid, and has high durability to an easy-to-crystallize/easy-to-scale medium.

Description

Energy-saving and maintenance-free centrifugal pump

Technical Field

The invention relates to a centrifugal pump, in particular to an energy-saving and maintenance-free centrifugal pump.

Background technique

In the fields of chemical industry, metallurgy, environmental protection, etc., centrifugal pumps are generally used to transport fluid media. The shaft seals of centrifugal pumps are frequently burned, the maintenance probability caused by leakage is high, the pump efficiency is low, the mechanical energy loss is large, and the energy medium consumption caused by the use of mechanical seal isolation fluid has always troubled practitioners. Especially when the medium itself is easy to crystallize, contains solid particles, and the temperature is high (>150℃), it is easy to cause shaft seal damage, resulting in a large amount of process medium leakage, affecting the stability of the process system and safety and environmental protection factors. Specifically:

1) When the shaft seal adopts packing seal, although it is cheap, simple in structure, and easy to install and maintain, it has a short working cycle, a high leakage rate, and the packing and the sleeve will wear, which will not only generate additional mechanical energy loss, but also increase the probability of leakage;

2) When the shaft seal adopts a single-end mechanical seal, although its sealing performance is better than that of a packing seal, for a medium containing solid particles, the solid particles are easy to enter the sealing surface between the dynamic and static rings, thereby causing uneven wear of the sealing surface until it is damaged, and the service life is short. The single-end mechanical seal is in a semi-liquid friction state during operation, and there is also a certain mechanical energy loss, but less than the packing seal;

3) When the shaft seal adopts double-end mechanical seal, although its sealing performance is better than that of single-end mechanical seal, it requires additional isolation fluid, consumes more energy medium, and has higher requirements for the cleanliness and pressure of the isolation fluid. There is also the risk of isolation fluid leaking into the process medium. Double-end mechanical seal is also in a semi-liquid friction state during operation, and there is also a certain mechanical energy loss, but it is less than that of packing seal and greater than that of single-end mechanical seal;

4) When the shaft seal adopts dynamic seal, although it can achieve effective sealing when the pump is running, when the pump stops, the medium will leak a lot;

5) When the shaft seal adopts a combination of dynamic seal and parking seal, the parking seal generally adopts packing, coil, spring seal, etc., which often has poor sealing performance, especially when the process medium is easy to crystallize and scale, it is easy to cause the parking seal to fail.

Therefore, the current centrifugal pumps urgently need to solve problems such as frequent maintenance of shaft seals, large mechanical energy losses, high energy medium consumption of isolation fluids, and poor durability against media prone to crystallization/scaling.

Summary of the invention

The object of the present invention is to provide an energy-saving and maintenance-free centrifugal pump which does not require frequent maintenance, has a small mechanical energy loss, does not require mechanical seal isolation fluid, and has high durability against crystallization/scaling media.

The technical solution adopted by the present invention is:

An energy-saving and maintenance-free centrifugal pump comprises a pump body (1), wherein the front end of the pump body (1) is provided with an inlet, the side portion is provided with an outlet, and the rear end is provided with a pump cover (3), an externally driven pump shaft (4) and a shaft sleeve (5) on the pump shaft (4) pass through the pump cover (3) and enter the pump body (1), and an impeller (2) with a guide flow channel is installed at the front end of the pump shaft (4); a dynamic seal and a shutdown seal are respectively provided inside and outside the pump body (1); the dynamic seal comprises an auxiliary blade (11) provided on the back side of the impeller (2), an auxiliary impeller chamber (12) located at the rear side of the impeller (2) and installed on the pump body (1), and a shaft sleeve (5) located in the auxiliary impeller chamber (12) and connected to the shaft sleeve (5). The stop seal is located at the rear side of the pump cover (3), and comprises a stationary ring (15) sleeved on the shaft sleeve (5) and installed on the pump cover (3), a moving ring (18) sleeved on the shaft sleeve (5) and located at the rear side of the stationary ring (15), and a traction block (20). The moving ring (18) adopts a metal bellows structure, and one end away from the stationary ring (15) is fixed on the shaft sleeve (5), and the other end is free. The traction block (20) is respectively connected to the two ends of the moving ring (18). When the machine is stopped, the sealing surface of the moving ring (18) and the stationary ring (15) are tightly attached. When the machine is running, the centrifugal force generated by the traction block (20) pulls the free end of the moving ring (18) away from the stationary ring (15).

Furthermore, one end of the traction block (20) is hinged to one end of the moving ring (18) away from the stationary ring (15), and the other end is connected to the free end of the moving ring (18) through a pull rope or is hinged to the free end of the moving ring (18) through a pull rod (19).

Furthermore, the stationary ring (15) is installed on the rear side of the pump cover (3) through the stationary ring gasket (16) and the stationary ring screw (14), and the end of the dynamic ring (18) away from the stationary ring (15) is fixed to the mounting ring through the dynamic ring screw (17), and the mounting ring is fixed to the shaft sleeve (5).

Furthermore, there are at least two traction blocks (20) orbiting around the ring (18).

Furthermore, the dynamic seals are provided in one group, two groups or more groups; the shutdown seals are provided in one group, two groups or more groups.

Furthermore, it also includes a sealing cover (8) and a purging device (9), wherein the sealing cover (8) surrounds and seals the shutdown seal and the connected pump shaft (4) and shaft sleeve (5), and the purging device (9) can purge the shutdown seal and the connected pump shaft (4) and shaft sleeve (5) in the sealing cover (8).

Furthermore, the purge medium of the purge device (9) is steam, clean water, compressed air or nitrogen.

Furthermore, it also includes a sealing cover (8) and a protective device (10), wherein the sealing cover (8) surrounds and seals the shutdown seal and the connected pump shaft (4) and shaft sleeve (5), and the protective device (10) can inject a protective medium of a certain pressure into the sealing cover (8).

Furthermore, the protection device (10) has monitoring and alarm functions. When it is detected that the pressure in the sealing cover (8) exceeds a certain value, the medium is protected from leaking out under the action of the medium pressure in the protection device (10), and an alarm is sounded locally and remotely.

Furthermore, it also includes an insulation sleeve (7) for heating the medium in the pump before the pump is started, the insulation sleeve (7) covers the pump body (1) and the pump cover (3), and the insulation sleeve (7) has an insulation medium inside or a heating component arranged inside.

The beneficial effects of the present invention are:

The centrifugal pump does not require frequent maintenance, has low mechanical energy loss, does not require mechanical seal isolation fluid, and has high durability against crystallization/scaling-prone media. The dynamic seal realizes sealing during operation: during operation, the auxiliary blade (11) can reduce the back pressure of the impeller (2) so that the axial force of the pump is in a balanced state. At the same time, the auxiliary impeller (13) rotates in the auxiliary impeller chamber (12) to form a negative pressure zone, so that the medium in the pump will not leak along the pump shaft (4) across the auxiliary impeller chamber (12) and the auxiliary impeller (13), and also avoids damage to the rear side components of the auxiliary impeller (13) by corrosive, high-temperature, and solid particle-containing media. In addition, the centrifugal force generated by the traction block (20) pulls the free end of the dynamic ring (18) away from the static ring (15), and the two are connected. The problems of sealing surface wear and mechanical energy loss will not occur; the shutdown seal realizes the sealing when the machine is shut down: when the machine is shut down, the sealing surfaces of the dynamic ring (18) and the static ring (15) are tightly attached to each other, realizing the sealing of the joint. At the same time, the dynamic ring (18) adopts a metal bellows structure, which is resistant to high temperature, has good end face wear resistance, large load-bearing capacity, and stable operation. The elastic metal ring sheet inside it will form a labyrinth seal, avoiding the wear and corrosion of the medium on the shaft sleeve (5) and the pump shaft (4). There is no need to set a sealing ring, which solves the problem of sealing ring deterioration and failure under high temperature (>150°C). There is no need for mechanical seal isolation fluid, which reduces friction resistance, has good tracking and shock resistance, and has a large tolerance for the vibration and deflection of the pump shaft (4). The centrifugal pump has high durability for dangerous media that are easy to crystallize, scale, fixed at room temperature, flammable, explosive, etc., and can be widely used in the fields of chemical, metallurgical, and environmental protection fluid medium transportation.

Contents of attached pictures

FIG. 1 is a schematic structural diagram of an energy-saving and maintenance-free centrifugal pump according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of the shutdown seal in the embodiment of the present invention when the machine is shut down.

FIG. 3 is a schematic diagram of the shutdown seal in operation according to an embodiment of the present invention.

In the figure: 1- pump body; 2- impeller; 3- pump cover; 4- pump shaft; 5- shaft sleeve; 6- bearing; 7- insulation sleeve; 8- sealing cover; 9- purge device; 10- protection device; 11- auxiliary blade; 12- auxiliary impeller chamber; 13- auxiliary impeller; 14- stationary ring screw; 15- stationary ring; 16-static ring gasket; 17-dynamic ring screw; 18-dynamic ring; 19-pull rod; 20-traction block.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figures 1 to 3, an energy-saving and maintenance-free centrifugal pump includes a pump body 1, the front end of the pump body 1 is provided with an inlet, the side is provided with an outlet, and the rear end is provided with a pump cover 3, the externally driven pump shaft 4 and the shaft sleeve 5 on the pump shaft 4 pass through the pump cover 3 and enter the pump body 1, and the front end of the pump shaft 4 is provided with an impeller 2 with a guide flow channel; the inside and outside of the pump body 1 are respectively provided with a dynamic seal and a shutdown seal; the dynamic seal includes an auxiliary blade 11 arranged on the back of the impeller 2, an auxiliary impeller chamber 12 located at the rear side of the impeller 2 and installed on the pump body 1, and a pump cover 3 is located in the auxiliary impeller chamber 12 and connected to the pump body 1. The auxiliary impeller 13 is connected to the shaft sleeve 5; the shutdown seal is located at the rear side of the pump cover 3, including a static ring 15 sleeved on the shaft sleeve 5 and installed on the pump cover 3, a dynamic ring 18 sleeved on the shaft sleeve 5 and located at the rear side of the static ring 15, and a traction block 20. The dynamic ring 18 adopts a metal bellows structure and one end away from the static ring 15 is fixed to the shaft sleeve 5, and the other end is free. The traction block 20 is respectively connected to the two ends of the dynamic ring 18. When the machine is stopped, the dynamic ring 18 is tightly attached to the sealing surface of the static ring 15. When running, the centrifugal force generated by the traction block 20 pulls the free end of the dynamic ring 18 away from the static ring 15.

The centrifugal pump does not require frequent maintenance, has low mechanical energy loss, does not require mechanical seal isolation fluid, and has high durability against easy crystallization/scaling media. The dynamic seal realizes sealing during operation: during operation, the auxiliary blade 11 can reduce the back pressure of the impeller 2 to keep the axial force of the pump in a balanced state. At the same time, the auxiliary impeller 13 rotates in the auxiliary impeller chamber 12 to form a negative pressure zone, so that the medium in the pump will not leak along the pump shaft 4 across the auxiliary impeller chamber 12 and the auxiliary impeller 13, and also avoids damage to the rear side components of the auxiliary impeller 13 by corrosive, high-temperature, and solid particle-containing media. Moreover, the centrifugal force generated by the traction block 20 pulls the free end of the dynamic ring 18 away from the static ring 15, and no friction occurs between the two. The problems of sealing surface wear and mechanical energy loss; the shutdown seal realizes the sealing when the machine is shut down: when the machine is shut down, the sealing surface of the dynamic ring 18 and the static ring 15 are tightly attached to each other, realizing the sealing at the joint. At the same time, the dynamic ring 18 adopts a metal bellows structure, which is resistant to high temperature, has good end face wear resistance, large load-bearing capacity, and stable operation. The elastic metal ring sheet inside it will form a labyrinth seal to avoid the wear and corrosion of the medium on the sleeve 5 and the pump shaft 4. There is no need to set a sealing ring, which solves the problem of sealing ring deterioration and failure under high temperature>150℃. There is no need for mechanical seal isolation fluid, which reduces friction resistance, has good tracking and shock resistance, and has a large tolerance for the vibration and deflection of the pump shaft 4. The centrifugal pump has high durability for dangerous media that are easy to crystallize, scale, fixed at room temperature, flammable, explosive, etc., and can be widely used in the fields of chemical, metallurgical, and environmental protection fluid medium transportation.

As shown in Figures 1 to 3, in this embodiment, one end of the traction block 20 is hinged to the end of the moving ring 18 away from the static ring 15, and the other end is connected to the free end of the moving ring 18 through a pull rope or hinged to the free end of the moving ring 18 through a pull rod 19. The centrifugal force generated by the traction block 20 causes the side of the traction block 20 close to the free end of the moving ring 18 to swing away from the radial direction, thereby pulling the free end of the moving ring 18 away from the stationary ring 15 through the pull rope or pull rod 19. The weight, size and shape of the traction block 20 are calculated and designed based on the pulling force required to pull the free end of the moving ring 18 and the transmission path of the force, ensuring that the free end of the moving ring 18 can be pulled when a certain speed is exceeded without over-compressing the moving ring 18.

As shown in Figures 1 to 3, in this embodiment, the stationary ring 15 is installed on the rear side of the pump cover 3 through the stationary ring gasket 16 and the stationary ring screw 14, and the end of the dynamic ring 18 away from the stationary ring 15 is fixed to the mounting ring through the dynamic ring screw 17, and the mounting ring is fixed to the shaft sleeve 5. The installation method of the stationary ring 15 and the dynamic ring 18 is simple and reliable.

As shown in FIG. 1 to FIG. 3 , in this embodiment, at least two traction blocks 20 are distributed around the moving ring 18 , and the free ends of the moving ring 18 are pulled evenly away from the stationary ring 15 during operation.

The dynamic seals are provided with one, two or more groups, and the shutdown seals are provided with one, two or more groups. In short, the number of groups is selected according to the sealing needs and is not limited to a specific number.

As shown in FIG. 1 , in this embodiment, the rear end of the pump shaft 4 passes through the bearing 6 and is externally connected to a drive.

As shown in FIG1 , in this embodiment, a sealing cover 8 and a purging device 9 are also included. The sealing cover 8 surrounds and seals the shutdown seal and the connected pump shaft 4 and sleeve 5. The purging device 9 can purge the shutdown seal and the connected pump shaft 4 and sleeve 5 in the sealing cover 8. The purging medium of the purging device 9 can be steam, clean water, compressed air, nitrogen, etc. For media that are easy to crystallize, scale, and are viscous, or even solid at room temperature, the shutdown seal and the connected pump shaft 4 and sleeve 5 are purged before the pump is started by utilizing the sealing environment formed by the sealing cover 8 and the purging function of the purging device 9, so that the subsequent dynamic ring 18 is not restricted by the medium when moving, and the shutdown seal and the connected pump shaft 4 and sleeve 5 are purged when the pump is stopped, so that the sealing surfaces of the static ring 15 and the dynamic ring 18 are clean and fit tightly. The purge device 9 adopts a common structure, including pipelines, nozzles, valves, pressure pumps, and steam/water sources. The pressure pump pressurizes the medium in the water source through the pipeline to the nozzle for spraying, or the high-pressure steam generated by the steam source flows to the nozzle through the pipeline and sprays out. The valve can control the switch and flow of the pipeline.

As shown in Figure 1, in this embodiment, a sealing cover 8 and a protective device 10 are also included. The sealing cover 8 surrounds and seals the shutdown seal and the connected pump shaft 4 and sleeve 5. The protective device 10 can inject a protective medium of a certain pressure into the sealing cover 8. For high-temperature, toxic, flammable, explosive and other harmful media, when the seal fails, a protective medium of a certain pressure is injected into the sealing cover 8 through the protective device 10, and the pressure can be used to prevent the medium from leaking. The protective device 10 adopts a commonly used emergency protection structure, which can be a nitrogen protective device, a bladder-type energy storage pressure protective device, white oil and an ordinary energy storage pressureless protective device. The protection device 10 has monitoring and alarm functions. When it is detected that the pressure in the sealing cover 8 exceeds a certain value, the medium pressure in the protection device 10 protects the process medium from leaking out, and alarms are sounded locally and remotely.

As shown in FIG1 , in this embodiment, a heat preservation sleeve 7 for heating the medium in the pump before the pump is started is also included. The heat preservation sleeve 7 covers the pump body 1 and the pump cover 3. The heat preservation medium is passed through the heat preservation sleeve 7 or a heating component is arranged on the inside. For the medium that is easy to crystallize, scale, and become viscous, or even solid at room temperature, the heat preservation sleeve 7 heats the medium in the pump before the pump is started, thereby avoiding the cranking step before starting and the damage caused by the solid to the internal structural parts of the pump body 1. The heat preservation medium can be steam, superheated water, thermal oil, etc., and the heating component can be a heating wire, a heating plate, etc.

It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

An energy-saving and maintenance-free centrifugal pump comprises a pump body (1), wherein the front end of the pump body (1) is provided with an inlet, the side part is provided with an outlet, and the rear end is provided with a pump cover (3), an externally driven pump shaft (4) and a shaft sleeve (5) on the pump shaft (4) pass through the pump cover (3) and enter the pump body (1), and an impeller (2) with a guide flow channel is installed at the front end of the pump shaft (4); the pump body (1) is characterized in that: a dynamic seal and a shutdown seal are respectively provided inside and outside the pump body (1); the dynamic seal comprises an auxiliary blade (11) provided on the back side of the impeller (2), an auxiliary impeller chamber (12) located at the rear side of the impeller (2) and installed on the pump body (1), and a shaft sleeve (5) located in the auxiliary impeller chamber (12) and connected to the shaft sleeve (5) ) connected to an auxiliary impeller (13); a shutdown seal is located at the rear side of the pump cover (3), comprising a stationary ring (15) sleeved on the shaft sleeve (5) and installed on the pump cover (3), a dynamic ring (18) sleeved on the shaft sleeve (5) and located at the rear side of the static ring (15), and a traction block (20); the dynamic ring (18) adopts a metal bellows structure, and one end away from the static ring (15) is fixed on the shaft sleeve (5), and the other end is free; the traction block (20) is respectively connected to the two ends of the dynamic ring (18); when the machine is stopped, the sealing surface of the dynamic ring (18) and the static ring (15) are tightly attached; when the machine is running, the centrifugal force generated by the traction block (20) pulls the free end of the dynamic ring (18) away from the static ring (15).
The energy-saving and maintenance-free centrifugal pump as described in claim 1 is characterized in that one end of the traction block (20) is hinged to the end of the moving ring (18) away from the static ring (15), and the other end is connected to the free end of the moving ring (18) through a pull rope or is hinged to the free end of the moving ring (18) through a pull rod (19).
The energy-saving and maintenance-free centrifugal pump as described in claim 1 is characterized in that: the stationary ring (15) is installed on the rear side of the pump cover (3) through the stationary ring gasket (16) and the stationary ring screw (14), and the end of the movable ring (18) away from the stationary ring (15) is fixed to the mounting ring through the movable ring screw (17), and the mounting ring is fixed to the shaft sleeve (5).
The energy-saving and maintenance-free centrifugal pump according to claim 1 is characterized in that: the number of the orbiting rings (18) of the traction block (20) is at least two.
The energy-saving and maintenance-free centrifugal pump according to claim 1 is characterized in that: the dynamic seals are provided with one group, two groups or more groups; the shutdown seals are provided with one group, two groups or more groups.
The energy-saving and maintenance-free centrifugal pump as described in any one of claims 1 to 5 is characterized in that it also includes a sealing cover (8) and a purge device (9), the sealing cover (8) surrounds and seals the shutdown seal and the connected pump shaft (4) and shaft sleeve (5), and the purge device (9) can purge the shutdown seal and the connected pump shaft (4) and shaft sleeve (5) in the sealing cover (8).
The energy-saving and maintenance-free centrifugal pump according to claim 6 is characterized in that the purge medium of the purge device (9) is steam, clean water, compressed air or nitrogen.
The energy-saving and maintenance-free centrifugal pump according to any one of claims 1 to 5, characterized in that it also includes a sealing cover (8) The sealing cover (8) surrounds and seals the shutdown seal and the connected pump shaft (4) and shaft sleeve (5), and the protective device (10) can inject a protective medium with a certain pressure into the sealing cover (8).
The energy-saving and maintenance-free centrifugal pump as described in claim 8 is characterized in that the protection device (10) has monitoring and alarm functions. When it is monitored that the pressure in the sealing cover (8) exceeds a certain pressure, the medium pressure in the protection device (10) protects the process medium from leakage, and alarms are given locally and remotely.
The energy-saving and maintenance-free centrifugal pump as described in any one of claims 1 to 5 is characterized in that it also includes an insulation sleeve (7) for heating the medium in the pump before the pump is started, the insulation sleeve (7) covers the pump body (1) and the pump cover (3), and the insulation sleeve (7) has an insulation medium inside or a heating component is arranged on the inside.