Automatic pressurization device for water-lubricated bearings during low-speed phase of pump

Abstract

The application discloses a kind of automatic pressurizing device for pump low-speed stage water-lubricated bearing in the field of hydraulic machinery, water-lubricated bearing is equipped on pump, and automatic pressurizing device injects water with set pressure to water-lubricated bearing, and automatic pressurizing device includes water inlet pipe, water tank and water outlet pipe connected in sequence;The water inlet pipe is connected to the outlet section of pump;Valve for controlling on-off is equipped on the water inlet pipe;The water outlet pipe is connected to water-lubricated bearing;Spring top cover and spring for blocking water inlet pipe are equipped in the water tank;The spring extrudes spring top cover, and spring top cover is on the outlet of water inlet pipe;The application adds water to pump water-lubricated bearing, which can effectively alleviate the vibration and noise caused by shaft eccentric rotation to water-lubricated bearing friction, and due to the lubrication and cooling effect of water, friction damage will also be weakened to a certain extent, the application has simple structure, small size, low cost, easy implementation, improves the working life of shaft and water-lubricated bearing.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic machinery technology, specifically relating to a water-lubricated bearing pressurization device. Background Technology

[0002] In large-scale pumping station systems of water conservancy projects, common lubrication methods for sliding bearings include water lubrication and oil lubrication. Water-lubricated bearings use water as a lubricant. Through the wedge-shaped gap between the journal and the bushing, the viscosity of water, and the rotation of the journal, a supporting force is generated, forming a lubricating water film, which is a type of hydrodynamic lubrication. Compared with oil lubrication, water-lubricated bearings often use river water directly for lubrication, and have advantages such as simple mechanical structure.

[0003] Water has a strong chemical corrosive effect on metallic materials. Since shafts are made of metal, the friction pair materials in water-lubricated bearings are mostly non-metallic materials. Common water-lubricated friction pair materials include rubber, plastics, ceramics, graphite, and polymers. Furthermore, the supporting force of a fluid lubrication film is approximately proportional to viscosity, proportional to velocity, and inversely proportional to the square of the film thickness. Because water viscosity is lower than oil viscosity, under the same conditions, the supporting force generated by water lubrication is less than that of oil lubrication. During the pump start-up phase of large pump stations, in low-speed operating conditions, and in special situations with frequent start-stop cycles, the journal speed is insufficient, making it difficult for water-lubricated bearings to generate effective supporting force. This results in dry or mixed friction between the journal and the bearing, easily causing damage to the journal and bearing. Moreover, frequent dry or mixed friction will significantly reduce the service life of the bearing and shaft. Severe wear, if not detected in time, can lead to pump station malfunctions or even shutdowns. Summary of the Invention

[0004] The purpose of this invention is to provide an automatic pressurization device for water-lubricated bearings in the low-speed stage of a pump, to prevent wear of the water-lubricated bearings and journals, improve the service life of the shaft and water-lubricated bearings, and ensure the safe operation of the unit.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An automatic pressurization device for a water-lubricated bearing during the low-speed phase of a pump is disclosed. The pump is equipped with a water-lubricated bearing, and the automatic pressurization device injects water at a set pressure into the water-lubricated bearing. The automatic pressurization device includes an inlet pipe, a water tank, and an outlet pipe connected in sequence. The inlet pipe is connected to the outlet section of the pump. A valve for controlling the on / off state is provided on the inlet pipe. The outlet pipe is connected to the water-lubricated bearing. The water tank contains a spring top cover and a spring for blocking the inlet pipe. The spring compresses the spring top cover, which presses against the outlet of the inlet pipe.

[0007] Preferably, the end of the water inlet pipe is provided with a first threaded pipe for connection; the outer diameter of the first threaded pipe is larger than the outer diameter of the water inlet pipe; the end of the water outlet pipe is provided with a second threaded pipe for connection; the outer diameter of the second threaded pipe is larger than the outer diameter of the water outlet pipe.

[0008] Preferably, the water tank is provided with multiple water outlet pipes evenly arranged around it, and each water outlet pipe is connected to a corresponding water-lubricated bearing.

[0009] Preferably, a filter screen is provided at the connection between the water tank and the water outlet pipe; the filter screen is connected to the inner wall of the water tank.

[0010] Preferably, the water tank is provided with a top column; the spring is sleeved on the top column, one side of the spring is located at the bottom of the water tank, and the other side of the spring is connected to the spring top cover; when the water pressure is greater than the threshold and the spring compression reaches the designed opening, the top column presses against the lower part of the spring top cover.

[0011] Preferably, the water tank includes an upper tank and a lower tank; the upper tank and the lower tank are connected by bolts; the upper tank is connected to the water inlet pipe, and the lower tank is connected to the water outlet pipe.

[0012] Preferably, the spring top cover is a frustum, the radius of the side of the spring top cover connected to the spring is larger than the radius of the other side of the spring top cover, and the other side of the spring top cover rests against the outlet of the water inlet pipe.

[0013] Preferably, the spring constant is:

[0014]

[0015]

[0016] In the formula: n1 is the rated speed of the pump, in r / min; n2 is the actual speed of the pump, in r / min; H1 is the head of the pump at its rated speed, in m; H2 is the actual head of the pump, in m; ∆x is the pre-given spring compression, in m; ρ is the density of water; g is the acceleration due to gravity; π is pi; h f2 D is the head loss of the inlet pipe, in meters; D is the diameter of the inlet pipe, in meters.

[0017] Preferably, the height of the top column is:

[0018]

[0019] In the formula: L is the height of the water tank, in meters; t is the wall thickness of the water tank, in meters; and x is the design opening of the spring top cover, in meters.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0021] The pressurization device of this invention includes an inlet pipe, a water tank, and an outlet pipe connected in sequence. The inlet pipe is connected to the outlet section of the pump, and the outlet pipe is connected to a water-lubricated bearing. Adding water to the pump's water-lubricated bearing can effectively alleviate the vibration and noise caused by friction due to the eccentric rotation of the shaft. Simultaneously, due to the lubrication and cooling effect of the water, friction damage is also reduced to a certain extent. This invention has a simple structure, small size, low cost, and is easy to implement. It prevents wear on the water-lubricated bearing and journal, improves the service life of the shaft and water-lubricated bearing, and ensures the safe operation of the unit.

[0022] The water tank of the present invention is provided with a spring top cover and a spring for blocking the water inlet pipe; the spring compresses the spring top cover, and the spring top cover is pressed against the outlet of the water inlet pipe. When the water pressure reaches a certain strength, the spring top cover is opened to add water to the water lubrication bearing, ensuring that the water entering the water lubrication bearing has a set pressure, reducing the friction between the water lubrication bearing and the shaft and improving the pump operating efficiency. Attached Figure Description

[0023] Figure 1 This is a structural diagram of an automatic pressurization device for water-lubricated bearings in the low-speed stage of a pump, provided by an embodiment of the present invention.

[0024] Figure 2 This is a structural diagram of the pump provided in an embodiment of the present invention.

[0025] In the diagram: 1 First threaded pipe, 2 Inlet pipe, 3 Valve, 4 Water tank, 5 Outlet pipe, 6 Second threaded pipe, 7 Spring top cover, 8 Spring, 9 Top column, 10 Filter screen, 11 Pump, 12 Water lubricated bearing. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0027] It should be noted that in the description of this invention, the terms "front," "rear," "left," "right," "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "front," "rear," "left," "right," "upper," and "lower" used in the description of this invention refer to the directions shown in the accompanying drawings, while the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0028] Taking a 20ZLB-70 pump as an example, the impeller angle is 0° and the design flow rate is 2099 m³ / h. 3The pump has a head of 7.0 m and a rated speed of 980 r / min. The pipe diameter at the pump outlet is 0.45 m. When the pump operates at a low speed of 150 r / min, the water-lubricated bearing rubs against the shaft, causing severe vibration and noise. This device is used to reduce the damage caused by friction.

[0029] like Figure 1-2 As shown, an automatic pressurization device for a water-lubricated bearing in the low-speed stage of a pump is disclosed. The pump 11 is equipped with a water-lubricated bearing 12. The automatic pressurization device injects water at a set pressure into the water-lubricated bearing 12. The automatic pressurization device includes an inlet pipe 2, a water tank 4, and an outlet pipe 5 connected in sequence. The end of the inlet pipe 2 is provided with a first threaded pipe 1 for connection. The outer diameter of the first threaded pipe 1 is larger than the outer diameter of the inlet pipe 2, facilitating the installation of the inlet pipe 2. The inlet pipe 2 is connected to the outlet section of the pump 11 through the first threaded pipe 1. A valve 3 is provided on the inlet pipe 2 to control the flow of water. When the pump starts, the ball valve 3 can be opened to allow water to enter the inlet pipe 2, reducing friction between the water-lubricated bearing and the shaft and improving pump operating efficiency. When the pump speed reaches the rated speed, the water-lubricated bearing does not need additional water, and the ball valve 3 can be closed to stop adding water to the water-lubricated bearing.

[0030] The end of the water outlet pipe 5 is provided with a second threaded pipe 6 for connection; the outer diameter of the second threaded pipe 6 is larger than the outer diameter of the water outlet pipe 5; the water outlet pipe 5 is connected to the water lubricating bearing 12 through the second threaded pipe 6; the pressurizing device transmits water from the pump outlet section to the water lubricating bearing to reduce the wear of the water lubricating bearing and shaft during the low speed stage of the pump; multiple water outlet pipes 5 are evenly arranged around the water tank 4, each water outlet pipe 5 is connected to the corresponding water lubricating bearing 12, and the water supply efficiency to the water lubricating bearing 12 is improved through multiple water outlet pipes 5; a filter screen 10 is provided at the connection between the water tank 4 and the water outlet pipe; the filter screen 10 is connected to the inner wall of the water tank 4, and filters impurities in the water to prevent impurities in the water from entering the water lubricating bearing.

[0031] The water tank 4 includes an upper tank and a lower tank; the upper tank and the lower tank are connected by bolts; the upper tank is connected to the water inlet pipe 2, and the lower tank is connected to the water outlet pipe 5. This structure facilitates the installation of the spring, spring top cover, and top column, and also facilitates the cleaning of impurities inside the water tank 5; the water tank 4 is equipped with a spring top cover 7 and a spring 8 for blocking the water inlet pipe; the spring 8 compresses the spring top cover 7, and the spring top cover 7 is pressed against the outlet of the water inlet pipe 2 to ensure that the water entering the water lubrication bearing has a set pressure; the water tank 4 is equipped with a top column 9; the spring 8 is sleeved on the top column 9, one side of the spring 8 is located at the bottom of the water tank 4, and the other side of the spring 8 is connected to the spring top cover 7; when the water pressure is greater than the threshold, when the compression of the spring 8 reaches the designed opening, the top column 9 presses against the lower part of the spring top cover 7 to prevent the spring from being compressed too much, and at the same time reduce the size of the water tank 4.

[0032] The spring top cover 9 is a frustum. The radius of the side of the spring top cover 7 connected to the spring 8 is larger than that of the other side of the spring top cover 7. The other side of the spring top cover 7 rests against the outlet of the water inlet pipe 2. The material of the spring top cover 7 is rubber. The frustum structure of the spring top cover 7 facilitates the sealing of the outlet of the water inlet pipe 2.

[0033] Working principle: When the water pump is started, the ball valve 3 can be opened to allow water to enter the inlet pipe 2. When the water pressure reaches the design value, the spring top cover 7 is opened to add water to the water-lubricated bearing, reducing the friction between the water-lubricated bearing and the shaft and improving the pump's operating efficiency. When the water pump speed reaches the rated speed, the water-lubricated bearing does not need to be replenished with water. The ball valve 3 can be closed to stop replenishing water to the water-lubricated bearing.

[0034] The design process of a water-lubricated bearing pressurization device includes the following steps: The recommended value ranges for the dimensions of each part of this water-lubricated bearing device used in the low-speed stage of pump station pumps are as follows: Inner diameter D of inlet pipe 2 [0.01m, 0.2m]; upper bottom diameter of spring top cover 7 [0.01m, 0.5m], lower bottom diameter equal to 1.5 times the upper bottom diameter, top angle [30°, 60°]; design opening x [0.005m, 0.3m]; inner diameter of water tank 4 [0.01m, 0.5m], height L of water tank 4 [0.05m, 1.0m], wall thickness t of water tank 4 [0.001m, 0.2m]; inner diameter of outlet pipe 5 [0.001m, 0.2m]; pre-compression amount ∆x of spring 8 [0.001m, 0.5m]; diameter of top column 9 [0.01m, 0.5m].

[0035] When pump 11 is running at low speed, water is added to the water-lubricated bearing, and the pump flow rate and head are estimated using the pump similarity law.

[0036] The preset formula for the flow rate Q2 of the pump 11 is:

[0037] =321 m 3 / h

[0038] In the formula, The rated speed of the pump is given in r / min. The actual pump speed, in r / min; The flow rate at the pump's rated speed, in meters per second (m³). 3 / s; The actual flow rate of the pump, in meters (m³). 3 / s;

[0039] The flow rate of the pump 11 The default formula is:

[0040] =0.16m

[0041] In the formula, The rated speed of the pump is given in r / min. The actual pump speed, in r / min; Head at rated pump speed, in meters; The actual head of the pump, in meters (m).

[0042] The inlet pipe 2 of this device has a diameter of D = 0.06m; the water tank 4 has a diameter of 0.12m, a height of L of 0.15m, and a wall thickness of t of 0.01m; the pre-compression of spring 8 is ∆x = 0.1m, and the design opening of the spring top cover 7 is x = 0.06m. The outlet pipe 5 has a diameter of 0.01m. The top column 9 has a diameter of 0.04m; the density of water is ρ = 1000Kg / m3; π = 3.14; the local gravitational acceleration is g = 9.8m / s2; h f2 =5%H1=0.008m, which is generally taken as 1%~10% of the pump's design head.

[0043] Based on the actual pump head H2 and the inlet pipe diameter D, the formula for calculating the elastic coefficient of the spring 8 is as follows:

[0044] = 44.3 N / m

[0045] In the formula: The spring compression is a pre-defined value; ρ is the density of water; g is the acceleration due to gravity; π is pi. D is the head loss of the inlet pipe; D is the diameter of inlet pipe 2, ranging from 0.01m to 0.2m.

[0046] When the water pressure exceeds the threshold, and the spring compression reaches the designed opening, the top post 9 presses against the lower part of the spring top cover 7. The designed height L0 of the top post 9 is calculated as follows:

[0047] =7cm

[0048] In the formula: L is the height of water tank 4, in meters; t is the wall thickness of water tank 4, in meters; x is the design opening of spring top cover 7, in meters.

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An automatic pressurization device for a water-lubricated bearing in the low-speed stage of a pump, wherein the pump is equipped with a water-lubricated bearing, characterized in that, An automatic pressurizing device injects water at a set pressure into the water-lubricated bearing. The automatic pressurizing device includes an inlet pipe (2), a water tank (4), and an outlet pipe (5) connected in sequence. The inlet pipe (2) is connected to the outlet section of the pump (12). A valve (3) for controlling the on / off state is provided on the inlet pipe (2). The outlet pipe (5) is connected to the water-lubricated bearing (11). The water tank is provided with a spring top cover (7) and a spring (8) for blocking the inlet pipe. The spring compresses the spring top cover (7), and the spring top cover (7) presses against the outlet of the inlet pipe. The water tank (4) is provided with a top column (9); the spring (8) is sleeved on the top column (9), one side of the spring is set at the bottom of the water tank (4), and the other side of the spring is connected to the spring top cover (7); when the water pressure is greater than the threshold and the spring compression reaches the designed opening, the top column (9) presses against the lower part of the spring top cover (7); The spring constant is: ； ； In the formula: The rated speed of the pump is given in r / min. The actual pump speed, in r / min; Head at rated pump speed, in meters; The actual head of the pump, in meters (m). The spring compression is a pre-defined value in meters (m); ρ is the density of water; g is the acceleration due to gravity; π is pi (π). D is the head loss of the inlet pipe, in meters; D is the diameter of the inlet pipe, in meters. The height of the top column is: ； In the formula: L is the height of the water tank, in meters; t is the wall thickness of the water tank, in meters; and x is the design opening of the spring top cover, in meters.

2. The automatic pressurization device for water-lubricated bearings in the low-speed stage of a pump according to claim 1, characterized in that, The end of the water inlet pipe (2) is provided with a first threaded pipe (1) for connection; the outer diameter of the first threaded pipe is larger than the outer diameter of the water inlet pipe; the end of the water outlet pipe (5) is provided with a second threaded pipe (6) for connection; the outer diameter of the second threaded pipe is larger than the outer diameter of the water outlet pipe.

3. The automatic pressurization device for water-lubricated bearings in the low-speed stage of a pump according to claim 1, characterized in that, Multiple water outlet pipes (5) are evenly arranged around the water tank (4), and each water outlet pipe (5) is connected to a corresponding water-lubricated bearing.

4. An automatic pressurization device for water-lubricated bearings in the low-speed stage of a pump, as described in claim 1 or 3, is characterized in that... A filter screen (10) is provided at the connection between the water tank (4) and the water outlet pipe; the filter screen (10) is connected to the inner wall of the water tank.

5. The automatic pressurization device for water-lubricated bearings in the low-speed stage of a pump according to claim 1, characterized in that, The water tank (4) includes an upper tank and a lower tank; the upper tank and the lower tank are connected by bolts; the upper tank is connected to the water inlet pipe and the lower tank is connected to the water outlet pipe.

6. The automatic pressurization device for water-lubricated bearings in the low-speed stage of a pump according to claim 1, characterized in that, The spring top cover (7) is a frustum. The radius of the side of the spring top cover connected to the spring is greater than that of the other side of the spring top cover, and the other side of the spring top cover (7) is pressed against the outlet of the water inlet pipe.

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