Water pump cavitation inhibition device

Abstract

The utility model discloses a water pump cavitation inhibition device which comprises a circulation pipeline, a steam-water separator, a mixer, a cooling heat exchanger and a pump, the steam-water separator, the mixer, the cooling heat exchanger and the pump are sequentially arranged on the circulation pipeline, a liquid level sensor is arranged on the steam-water separator, and the steam-water separator is connected with an exhaust pipeline and a liquid discharge pipeline. The steam-water separator is connected with the mixer through a liquid discharging pipeline, the mixer is further connected with a water supplementing pipeline, and a control valve is arranged on the water supplementing pipeline. According to the utility model, heat exchange can be carried out on the working medium in the circulating pipeline through water replenishing, and secondary cooling can be carried out on the working medium in the circulating pipeline through the cooling heat exchanger, so that effective net positive suction head is controlled, the temperature of the working medium is reduced, the effective net positive suction head NPSHr is ensured to rise, and the problem of cavitation of the pump is solved.

Description

Technical Field

[0001] This utility model relates to the field of water pump application equipment technology, and more specifically to a water pump cavitation suppression device. Background Technology

[0002] Currently, the pump is cooled only by a single heat exchanger without any diagnostic measures. When operating conditions change, the possibility of pump cavitation will increase significantly. Therefore, this method can only reduce the possibility of cavitation to a certain extent, but cannot accurately determine whether cavitation has occurred and take corresponding adjustments. Utility Model Content

[0003] The technical problem to be solved by this utility model is how to prevent water pump cavitation.

[0004] This utility model solves the above-mentioned technical problems through the following technical means: a water pump cavitation suppression device, including a circulation pipeline and a steam-water separator, a mixer, a cooling heat exchanger, and a pump arranged sequentially on the circulation pipeline. The steam-water separator is equipped with a liquid level sensor, and the steam-water separator is connected to an exhaust pipeline and a drain pipeline. The steam-water separator is connected to the mixer through the drain pipeline, and the mixer is also connected to a water supply pipeline. A control valve is provided on the water supply pipeline.

[0005] As a preferred technical solution, pressure sensors are installed on both the upstream and downstream circulation pipelines of the pump.

[0006] As a preferred technical solution, the pump is connected to a power sensor.

[0007] As a preferred technical solution, the control valve includes an electrically adjustable valve.

[0008] As a preferred technical solution, the cooling heat exchanger is also connected to a second heat exchange pipeline, which exchanges heat with the circulation pipeline in a countercurrent manner.

[0009] As a preferred technical solution, an electric regulating valve is provided on the second heat exchange pipeline.

[0010] As a preferred technical solution, the exhaust pipe is connected to the top of the steam-water separator, and the liquid drain pipe is connected to the bottom of the steam-water separator.

[0011] As a preferred technical solution, the pressure sensor includes a pressure sensor one located upstream of the pump and a pressure sensor two located downstream of the pump.

[0012] As a preferred technical solution, a temperature sensor is installed on the circulation pipeline located downstream of the cooling heat exchanger and upstream of the pump.

[0013] As a preferred technical solution, the flow direction of the working fluid in the second heat exchange pipeline is opposite to the flow direction of the working fluid in the circulation pipeline.

[0014] The beneficial effects of this utility model are as follows:

[0015] (1) In this utility model, by setting up a cooling heat exchanger and adding a mixer upstream of the cooling heat exchanger, the mixer is connected to the water supply pipeline, which can exchange heat with the working fluid in the circulation pipeline through water supply. The cooling heat exchanger can cool the working fluid in the circulation pipeline for a second time, thereby controlling the effective net positive suction head (NPSHr) and reducing the working fluid temperature to ensure that the effective NPSHr increases, thus solving the pump cavitation problem. Attached Figure Description

[0016] Figure 1 A schematic diagram of the overall structure provided for an embodiment of this utility model;

[0017] Reference numerals: 1. Steam generating heat exchanger; 2. Steam-water separator; 3. Liquid level sensor; 4. Mixer; 5. Electric regulating valve one; 6. Cooling heat exchanger; 7. Electric regulating valve two; 8. Temperature sensor; 9. Pressure sensor one; 10. Pump; 11. Power sensor; 12. Pressure sensor two. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0019] See Figure 1 The water pump cavitation suppression device includes a circulation pipeline and a steam generating heat exchanger 1, a steam-water separator 2, a mixer 4, a cooling heat exchanger 6, and a pump 10 arranged sequentially on the circulation pipeline. The steam generating heat exchanger 1 is also connected to a first heat exchange pipeline. The heat medium enters the steam generating heat exchanger 1 through the first heat exchange pipeline to cool down and dissipate heat, and is output through the first heat exchange pipeline. At the same time, the liquid water in the circulation pipeline is heated and turned into a two-phase steam-water mixture that flows out into the steam-water separator 1. The overall flow direction is countercurrent heat exchange. It should be noted that countercurrent refers to the flow opposite to the flow direction of the working medium in the circulation pipeline. The working medium is water, but it can also be other working medium materials. The top of the steam-water separator 2 is connected to a steam output pipeline, and the bottom is connected to the mixer 4. The steam-water mixture is separated into two phases by the steam-water separator. Saturated steam flows out from the top of the steam-water separator 2, while saturated water settles to the bottom, thereby separating water and steam.

[0020] The steam-water separator 2 is equipped with a liquid level sensor 3, which is used to monitor the liquid level of the steam-water separator 2 and output a signal. The mixer 4 is connected to a water supply pipeline. The mixer 4 mixes the water from the steam-water separator with the water input from the water supply pipeline. This mixing can cool the water from the steam-water separator, which is the circulating working fluid. The water supply pipeline is equipped with an electric regulating valve 5, which is used to control the amount of water supplied. At the same time, it can also stabilize the liquid level in the steam-water separator 2, reduce the impact of liquid level changes on the pressure sensor 9, and thus improve the control accuracy of the entire system.

[0021] The cooling heat exchanger 6 is connected to a second heat exchange pipeline, which contains a cooling working medium, namely water. The cooling water cools the mixed water output from the mixer 4, which is a counter-current heat exchange. The second heat exchange pipeline is equipped with an electric regulating valve 7, which is used to control the flow rate of the cooling water in the second heat exchange pipeline, thereby adjusting the heat exchange efficiency.

[0022] A temperature sensor 8 and a pressure sensor 9 are sequentially installed along the flow direction of the working fluid in the circulation pipeline between the cooling heat exchanger 6 and the pump 10. The temperature sensor 8 monitors the temperature of the medium entering the pump, and the pressure sensor 9 monitors the pressure of the medium entering the pump. The pump 10 serves as the power unit for the circulation pipeline, and a power sensor 11 is connected to the pump 10 to monitor the input electrical power of the pump 10. A pressure sensor 12 is connected downstream of the pump 10 to monitor the pressure of the working fluid leaving the pump 10.

[0023] The suppression method includes the following steps:

[0024] S1. Liquid level control: The liquid level data is monitored in real time by the liquid level sensor 3 of the steam-water separator 2, and the liquid level is maintained at the set liquid level by controlling the electric regulating valve 5 on the water supply pipeline.

[0025] S2. Input the basic curve data of pump 10's flow rate, head, power and cavitation into the control system as a benchmark;

[0026] S3. Calculate the pump head using pressure sensor 9 and pressure sensor 12, and match the pump input power and required net positive suction head (NPSHr) of the pump corresponding to the calculated head from the basic curve data.

[0027] The head is calculated using the following formula: H=(p2-p1) / ρg;

[0028] Where H is the pump head, in meters (m); p1 and p2 are the liquid pressures at the pump inlet and outlet, i.e., the values ​​at pressure sensor 9 and pressure sensor 12, in Pa; and ρ is the liquid density, in kg / m³. 3; g is the acceleration due to gravity, with the unit of m / s 2 ;

[0029] S4. By monitoring the operating power of the pump 10 and comparing it with the pump input power corresponding to the head calculated in S3, if the actual pump power measured by the power sensor 11 is less than the matched power, it is determined that the pump is in the cavitation state;

[0030] S5. Based on the value of the outlet temperature of the cooling heat exchanger 6, i.e., the value of the temperature sensor 8, calculate the saturated vapor pressure of the water at the pump inlet by combining the following formula;

[0031]

[0032] Where:

[0033] P s is the pressure, with the unit of kPa; 0.13332 is the unit conversion coefficient when converting from mmHg to kPa; T is the temperature, with the unit of °C;

[0034] A, B, C: are coefficients respectively. Different media have different coefficients. In this embodiment, when calculating the saturated vapor pressure of water vapor, A is 7.96681, B is 1668.21, and C is 228;

[0035] S6. Based on the required net positive suction head NPSHr of the pump corresponding to the head calculated in S3 and the saturated vapor pressure P calculated in S5 s calculate and determine whether it is currently in the cavitation state according to the following formula;

[0036] Let T1 - P s / ρg - NPSHr = X; P1 is the value of the pressure sensor 9;

[0037] When X ≤ 0, the pump is in the cavitation state;

[0038] When X ≥ 0.5, the pump is in the non - cavitation state;

[0039] When 0 < X < 0.5, maintain the current judgment state;

[0040] Where ρ and g are the density of the medium and the acceleration due to gravity respectively. Here, g is taken as 9.81 m / s 2 When the medium is water, ρ is taken as 1000 kg / m 3 and 0.5 is for adjustment;

[0041] S7. When any step in S4 and S6 determines that the pump is in the cavitation state, increase the opening degree of the electric control valve 2 to reduce the outlet temperature of the cooling heat exchanger 6, and vice versa, to finally achieve the state where the pump is in the non - cavitation state.

[0042] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A water pump cavitation suppression device, characterized in that, It includes a circulation pipeline and a steam-water separator, a mixer, a cooling heat exchanger, and a pump arranged sequentially on the circulation pipeline. The steam-water separator is equipped with a liquid level sensor, and is connected to an exhaust pipeline and a drain pipeline. The steam-water separator is connected to the mixer through the drain pipeline, and the mixer is also connected to a water supply pipeline with a control valve.

2. The water pump cavitation suppression device according to claim 1, characterized in that, Pressure sensors are installed on the circulation pipelines located upstream and downstream of the pump.

3. The water pump cavitation suppression device according to claim 1, characterized in that, The pump is connected to a power sensor.

4. The water pump cavitation suppression device according to claim 1, characterized in that, The control valve includes an electrically adjustable valve.

5. The water pump cavitation suppression device according to claim 1, characterized in that, The cooling heat exchanger is also connected to a second heat exchange pipeline, which exchanges heat with the circulation pipeline in a countercurrent manner.

6. The water pump cavitation suppression device according to claim 5, characterized in that, The second heat exchange pipeline is equipped with an electric regulating valve.

7. The water pump cavitation suppression device according to claim 1, characterized in that, The exhaust pipe is connected to the top of the steam-water separator, and the liquid drain pipe is connected to the bottom of the steam-water separator.

8. The water pump cavitation suppression device according to claim 2, characterized in that, The pressure sensor includes a pressure sensor one located upstream of the pump and a pressure sensor two located downstream of the pump.

9. The water pump cavitation suppression device according to claim 1, characterized in that, A temperature sensor is installed on the circulation pipeline located downstream of the cooling heat exchanger and upstream of the pump.

10. The water pump cavitation suppression device according to claim 5, characterized in that, The flow direction of the working fluid in the second heat exchange pipeline is opposite to that in the circulation pipeline.

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