Intelligent flow self-adjusting system of condensate pump

Abstract

The invention relates to an intelligent flow self-adjusting system of a condensate pump, a flash tank is provided with an input port and an output port, and the input port of the flash tank is connected with a condensate collector; a pump body of the condensate pump is provided with a water inlet and a water outlet, and the water inlet of the pump body is connected to the output port of the flash tank through a communicating pipeline; the pressure balance pipeline is provided with two output ends, one output end of the pressure balance pipeline is communicated with a pump body of the condensate pump, the other output end of the pressure balance pipeline is communicated with the flash tank, and the pressure balance pipeline is used for introducing inert gas into the pump body of the condensate pump and the flash tank; the control module is used for collecting the liquid level height of the flash tank, controlling the condensate pump to be started after the liquid level height of the flash tank and the center height of a pump body impeller of the condensate pump reach a preset liquid level difference value, and controlling the flow of the condensate pump based on a flow function. The condensate pump has the effect of achieving intelligent self-adjustment of the flow of the condensate pump.

Description

Technical Field

[0001] The present application relates to the technical field of centrifugal pumps, and in particular to an intelligent flow self-regulating system for condensate pumps. Background Art

[0002] Condensate pumps are widely used in petrochemical, electric power, chemical fiber, and chemical industries where condensate circulation is required. The working principle of the condensate pump is to extract the condensate from the condenser through a specific mechanical structure. The condensate pump usually adopts a vertical barrel bag type double-layer shell structure, the first stage is a single suction or double suction form, and the secondary impeller is common to the final stage impeller, which is a single suction form. This design enables the condensate pump to effectively extract the condensate from the condenser and ensure stable operation under vacuum.

[0003] Domestic scholars have conducted a lot of research on condensate pumps, mainly focusing on several aspects such as condensate pump outlet pressure pulsation, internal unstable flow, and motor vibration. In the document "The Influence of Long and Short Blade Structure on the Pressure Pulsation Characteristics of Condensate Pump Outlet" (2022), Hu Jiang studied the influence of different long and short blade structures on the pressure pulsation characteristics of condensate pump outlet through numerical simulation methods, and found that the 3-long and 3-short blade structure has more obvious outlet pressure pulsation and more complex changes. d Under flow conditions, the pump outlet pipe presents multi-frequency excited pressure pulsation characteristics. In the document "Research on Unsteady Cavitation Characteristics of Condensate Pumps" (2021), Wang Xing used the renormalization group (RNG) k-ε turbulence model and the Zwart-Gerbe-Belamri cavitation model to simulate the flow inside the pump by combining experiments with numerical simulations. The influence of cavitation on the unstable radial force and blade load of the pump was discussed, and it was found that the average radial force increased significantly during the transition from the initial cavitation state to the supercavitation state. In the document "Diagnosis and Treatment of Vibration Failures of Vertical Condensate Pump Motors" (2021), Gao Lijun pointed out the serious impact of excessive vibration on the normal operation of steam turbine generator sets through actual case analysis. After a series of cause analyses of motor vibration, a variety of measures were taken to solve the problem, including test foundation reinforcement and rotor dynamic balancing. Through in-depth diagnosis, it was found that the root cause of the excessive motor vibration was the problem of the motor magnetic field center. It can be found that most of the existing public papers on condensate pumps study the impact of the structure of the condensate pump on the outlet pressure and internal flow, and there is no in-depth study on the characteristics of the condensate pump system.

[0004] With respect to the above-mentioned related technologies, the inventor believes that the current condensate pump cannot achieve self-regulation of flow rate, and therefore there are certain areas for improvement. Summary of the invention

[0005] In order to realize intelligent self-regulation of the flow rate of a condensate pump, the present application provides an intelligent self-regulation system for the flow rate of a condensate pump.

[0006] A condensate pump intelligent flow self-regulating system, comprising a condensate pump, a flash tank, a pressure balancing pipeline and a control module; The flash tank has an input port and an output port, and the input port of the flash tank is connected to a condensate collector; The condensate pump has a water inlet and a water outlet on its pump body, and the water inlet of the pump body is connected to the output port of the flash tank through a connecting pipe; The pressure balance pipeline has two output ends, one of which is connected to the pump body of the condensate pump, and the other is connected to the flash tank. The pressure balance pipeline is used to introduce inert gas into the pump body of the condensate pump and the flash tank. The control module is used to collect the liquid level height of the flash tank, and control the condensate pump to start after the liquid level height of the flash tank and the center height of the pump body impeller of the condensate pump reach a predetermined liquid level difference, and control the flow of the condensate pump based on the flow function.

[0007] Preferably, the control module controls the flow of the condensate pump based on the flow function, and performs calculation according to the energy equation formula, and the energy equation formula is as follows: H 1 +p 1 / ρg+v 1 2 / 2g=H 2 +p 2 / ρg+v 2 2 / 2g; In the formula, H 1 is the liquid level height of the flash tank, H 2 is the center height of the pump impeller, p 1 is the flash tank gas pressure, p 2 is the gas pressure at the center of the pump body, v 1 is the flash tank liquid surface velocity, v 2 is the pump outlet velocity, g is the gravitational acceleration, ρ is the density, where the flash tank liquid surface velocity v 1 =0; The pressure balance pipeline is used to pass inert gas into the pump body of the condensate pump and the flash tank, and control the gas pressure of the flash tank to be consistent with the gas pressure at the center of the pump body. The flow function can be obtained by converting the energy equation formula. The formula of the flow function is as follows: Where Hz is the difference between the liquid level of the flash tank and the center height of the impeller of the condensate pump, Q 1 is the flow rate of the flash tank, Q2 is the flow rate of the condensate pump body, A 2 It is the flow area of ​​the condensate pump.

[0008] Preferably, the inert gas is nitrogen.

[0009] Preferably, two output ends of the pressure balance pipeline are connected to the flash tank and the pump body of the condensate pump through lip seals respectively.

[0010] Preferably, the flow rate of the inert gas introduced into the pressure balance pipeline is 15-30NL / h.

[0011] Preferably, a pressure stabilizing device is connected to the pressure balancing pipeline.

[0012] Preferably, the pressure stabilizing device comprises a pressure stabilizing pipeline, the pressure stabilizing pipeline is connected to the pressure balancing pipeline, and a pressure reducing valve, a needle valve, a flow sensor and a pressure alarm are sequentially arranged on the pressure stabilizing pipeline.

[0013] Preferably, a pump inlet valve is installed on the connecting pipeline.

[0014] Preferably, a water outlet of the condensate pump body is connected to a water outlet pipeline, and a check valve and a pump outlet valve are installed on the water outlet pipeline.

[0015] Preferably, a pressure control valve is installed on the output end of the pressure balance pipeline connected to the pump body of the condensate pump.

[0016] In summary, the present application includes at least one of the following beneficial technical effects: 1. The condensate pump in this application will automatically adjust the delivery flow based on the flow function through the intelligent flow self-regulating system. It has a high degree of intelligence and does not require any pressure, liquid level, throttling and other instrument control designs. It also does not require a condensate collection gas-liquid separation storage tank, and does not require a control system such as a frequency converter.

[0017] 2. In the present application, the inert gas is introduced into the pump body of the condensate pump, thereby changing the NPSHr concept of the conventional condensate pump, and the vaporized medium is transported during operation without generating cavitation.

[0018] 3. In this application, when the condensate pump has zero flow, the conventional condensate pump has no liquid to take away the heat of the pump body, but nitrogen is introduced into the pump body of the condensate pump through the pressure balance pipeline, and the heat of dry friction can be cooled by nitrogen, thereby increasing the service life of the condensate pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the regulation flow chart of the condensate pump intelligent flow self-regulating system.

[0020] Figure 2It is the system block diagram of the condensate pump intelligent flow self-regulating system.

[0021] Figure 3 This is a schematic diagram of the structure of the voltage stabilizing device.

[0022] Explanation of the reference numerals in the accompanying drawings: 1. condensate pump; 101. pump body; 102. motor; 2. flash tank; 3. pressure balance pipeline; 4. condensate collector; 5. connecting pipeline; 6. pump inlet valve; 7. outlet pipeline; 8. check valve; 9. pump outlet valve; 10. pressure control valve; 11. pressure stabilizing device; 111. pressure stabilizing pipeline; 112. pressure reducing valve; 113. needle valve; 114. flow sensor; 115. pressure alarm. DETAILED DESCRIPTION

[0023] The following is combined with Figure 1-3 This application is described in further detail.

[0024] A condensate pump 1 intelligent flow self-regulating system, referring to Figure 1 and Figure 2 As shown, it includes a condensate pump 1, a flash tank 2, a pressure balance pipeline 3 and a control module.

[0025] The flash tank 2 has an input port and an output port. The input port is arranged at the upper part of the flash tank 2, and the output port is arranged at the lower part of the flash tank 2. The input port of the flash tank 2 is connected to a condensate collector 4, which is used to connect various steam devices to collect condensate generated by each steam device and continuously store it in the flash tank 2.

[0026] The condensate pump 1 includes a pump body 101 and a motor 102 connected to the pump body 101. The pump body 101 has a water inlet and a water outlet. The water inlet of the pump body 101 is connected to the output port of the flash tank 2 through a connecting pipe 5. A pump inlet valve 6 is installed on the connecting pipe 5. The pump inlet valve 6 is used to control the opening and closing of the connecting pipe 5.

[0027] The bottom of the pump body 101 is on the same horizontal line as the bottom of the flash tank 2. The water outlet of the pump body 101 is connected to a water outlet pipeline 7, on which a check valve 8 and a pump outlet valve 9 are installed in sequence. The pump outlet valve 9 is used to control the opening and closing of the water outlet pipeline 7, and the check valve 8 is used to prevent the water in the water outlet pipeline 7 from flowing back, thereby ensuring that the water flows in one direction in the water outlet pipeline 7.

[0028] The pressure balancing pipeline 3 has two output ends, one of which is connected to the pump body 101 of the condensate pump 1, and the other output end of the pressure balancing pipeline 3 is connected to the flash tank 2. The connecting position between the pressure balancing pipeline 3 and the flash tank 2 is located above the input port of the flash tank 2. The pressure balancing pipeline 3 is used to introduce inert gas into the pump body 101 of the condensate pump 1 and the flash tank 2.

[0029] It is worth noting that one of the output ends of the pressure balance pipeline 3 is connected to the pump body 101 of the condensate pump 1 through a lip seal, and the other output end of the pressure balance pipeline 3 is connected to the flash tank 2 through a lip seal. Among them, a pressure control valve 10 is installed on the output end of the pressure balance pipeline 3 connected to the pump body 101 of the condensate pump 1, and the pressure control valve 10 is used to control the opening and closing between the pressure balance pipeline 3 and the pump body 101 of the condensate pump 1.

[0030] In one embodiment, the inert gas is nitrogen. Other inert gases may also be used. This embodiment is described with nitrogen as the inert gas.

[0031] Reference Figure 3 As shown, a pressure stabilizing device 11 is connected to the pressure balancing pipeline 3, and the pressure stabilizing device 11 is used to stably input the inert gas from the pressure balancing pipeline 3 into the flash tank 2 and the pump body 101 of the condensate pump 1. The flow rate of the inert gas introduced into the pressure balancing pipeline 3 is 15-30NL / h. Preferably, the flow rate of the inert gas introduced into the pressure balancing pipeline 3 is 20NL / h.

[0032] In one embodiment, the pressure stabilizing device 11 includes a pressure stabilizing pipeline 111, the input end of the pressure stabilizing pipeline 111 is connected to a gas storage tank or other gas source, the output end of the pressure stabilizing pipeline 111 is connected to the pressure balancing pipeline 3, and the pressure stabilizing pipeline 111 is sequentially provided with a pressure reducing valve 112, a needle valve 113, a flow sensor 114 and a pressure alarm 115.

[0033] The high-pressure inert gas in the gas storage tank is reduced in pressure by the pressure reducing valve 112 and reaches the needle valve 113. The inert gas flow rate can be accurately controlled by adjusting the opening of the needle valve 113. The needle valve 113 can control the minimum gas flow rate in the pressure-stabilizing pipeline 111 to be above 15NL / h. The flow sensor 114 is used to monitor the flow rate of the inert gas in the pressure-stabilizing pipeline 111. If the value of the flow sensor 114 reaches the maximum at the minimum flow rate, it means that the pressure-stabilizing pipeline 111 leaks. The pressure alarm 115 is used to monitor the abnormal pressure value of the pressure-stabilizing pipeline 111 to prevent the pressure in the pressure-stabilizing pipeline 111 from being too high or too low.

[0034] A liquid level sensor is provided in the flash tank 2, and the liquid level sensor is used to collect the liquid level height in the flash tank 2. The control module is used to obtain the liquid level height of the flash tank 2 collected by the liquid level sensor, and control the condensate pump 1 to start after the liquid level height of the flash tank 2 and the center height of the impeller of the pump body 101 of the condensate pump 1 reach a predetermined liquid level difference, and control the flow rate of the condensate pump 1 based on the flow function.

[0035] Specifically, the control module controls the flow of the condensate pump 1 based on the flow function, and calculates according to the energy equation formula. The formula of the energy equation is as follows: H 1 +p 1 / ρg+v 1 2 / 2g=H 2 +p 2 / ρg+v 2 2 / 2g; In the formula, H 1 is the liquid level height of flash tank 2, H 2 is the center height of the pump body 101 impeller, p 1 is the gas pressure in flash tank 2, p 2 is the gas pressure at the center of the pump body 101, v 1 is the liquid surface velocity in flash tank 2, v 2 is the outlet flow rate of pump body 101, g is the acceleration of gravity, ρ is the density, where the liquid surface flow rate v of flash tank 2 1 =0; The pressure balance pipeline 3 is used to pass inert gas into the pump body 101 of the condensate pump 1 and the flash tank 2 to control the gas pressure of the flash tank 2 to be consistent with the gas pressure at the center of the pump body 101, that is, to control p 1 =p 2 Therefore, according to the flow rate in the pump body 101 of the condensate pump 1 in the energy equation After converting the energy equation formula, the flow function can be obtained. The formula of the flow function is as follows: Where Hz is the difference between the liquid level of the flash tank 2 and the center height of the impeller of the pump body 101 of the condensate pump 1, Q 1 is the flow rate of flash tank 2, Q 2 is the flow rate of the condensate pump 1 pump body 101, A 2 It is the flow area of ​​the pump body 101 of the condensate pump 1.

[0036] Therefore, the flow rate of the flash tank 2 and the flow rate of the pump body 101 of the condensate pump 1 change with the liquid level difference Hz between the liquid level height of the flash tank 2 and the impeller center height of the pump body 101 of the condensate pump 1. When the liquid level difference Hz approaches zero, the flow rate of the pump body 101 of the condensate pump 1 also approaches zero.

[0037] In summary, the condensate pump 1 flow self-regulating system of the present application has the following beneficial effects: 1. The condensate pump 1 in this application will automatically adjust the delivery flow based on the flow function through the intelligent flow self-regulating system. It has a high degree of intelligence and does not require any pressure, liquid level, throttling and other instrument control designs. It also does not require a condensate collection gas-liquid separation storage tank, nor does it require a control system such as a frequency converter.

[0038] 2. In the present application, by introducing inert gas into the pump body 101 of the condensate pump 1, the NPSHr concept of the conventional condensate pump 1 is changed, and the vaporized medium is transported during operation without generating cavitation.

[0039] 3. In the present application, when the condensate pump 1 has zero flow, the conventional condensate pump 1 has no liquid to take away the heat of the pump body 101, and nitrogen is introduced into the pump body 101 of the condensate pump 1 through the pressure balance pipeline 3. The heat of dry friction can be cooled by the nitrogen, thereby increasing the service life of the condensate pump 1.

[0040] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A condensate pump intelligent flow self-regulating system, characterized in that: It comprises a condensate pump (1), a flash tank (2), a pressure balance pipeline (3) and a control module; The flash tank (2) has an input port and an output port, and the input port of the flash tank (2) is connected to a condensate collector (4); The pump body (101) of the condensate pump (1) is provided with a water inlet and a water outlet, and the water inlet of the pump body (101) is connected to the outlet of the flash tank (2) via a connecting pipe (5); The pressure balancing pipeline (3) has two output ends, one of the output ends of the pressure balancing pipeline (3) is connected to the pump body (101) of the condensate pump (1), and the other output end of the pressure balancing pipeline (3) is connected to the flash tank (2), and the pressure balancing pipeline (3) is used to pass inert gas into the pump body (101) of the condensate pump (1) and the flash tank (2); The control module is used to collect the liquid level height of the flash tank (2), and control the condensate pump (1) to start after the liquid level height of the flash tank (2) and the center height of the impeller of the pump body (101) of the condensate pump (1) reach a predetermined liquid level difference, and control the flow rate of the condensate pump (1) based on a flow rate function.

2. The condensate pump intelligent flow self-regulating system according to claim 1 is characterized in that: The control module controls the flow rate of the condensate pump (1) based on the flow rate function, and performs calculation according to the energy equation formula. The energy equation formula is as follows: <h2 style=";text-align:left;direction:ltr">H1+p1 / ρg+v1<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> / 2g = H2 + p2 / ρg + v2<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> / 2g; Wherein, H1 is the liquid level height of the flash tank (2), H2 is the center height of the impeller of the pump body (101), p1 is the gas pressure of the flash tank (2), p2 is the gas pressure at the center of the pump body (101), v1 is the liquid surface flow velocity of the flash tank (2), v2 is the outlet flow velocity of the pump body (101), g is the gravitational acceleration, ρ is the density, wherein the liquid surface flow velocity v1 of the flash tank (2) = 0; The pressure balance pipeline (3) is used to pass inert gas into the pump body (101) of the condensate pump (1) and the flash tank (2), so as to control the gas pressure of the flash tank (2) to be consistent with the gas pressure at the center of the pump body (101). After converting the energy equation formula, a flow function can be obtained. The formula of the flow function is as follows: In the formula, Hz is the liquid level difference between the liquid level height of the flash tank (2) and the center height of the impeller of the pump body (101) of the condensate pump (1), Q1 is the flow rate of the flash tank (2), Q2 is the flow rate of the pump body (101) of the condensate pump (1), and A2 is the flow area of ​​the pump body (101) of the condensate pump (1).

3. The intelligent flow self-regulating system for condensate pump according to claim 1 is characterized in that: The inert gas is nitrogen.

4. The condensate pump intelligent flow self-regulating system according to claim 1 is characterized in that: The two output ends of the pressure balance pipeline (3) are respectively connected to the flash tank (2) and the pump body (101) of the condensate pump (1) through lip seals.

5. The condensate pump intelligent flow self-regulating system according to claim 1 is characterized in that: The flow rate of the inert gas introduced into the pressure balance pipeline (3) is 15-30NL / h.

6. The condensate pump intelligent flow self-regulating system according to claim 1 is characterized in that: The pressure balancing pipeline (3) is connected to a pressure stabilizing device (11).

7. The condensate pump intelligent flow self-regulating system according to claim 6 is characterized in that: The pressure stabilizing device (11) comprises a pressure stabilizing pipeline (111), the pressure stabilizing pipeline (111) is connected to the pressure balancing pipeline (3), and a pressure reducing valve (112), a needle valve (113), a flow sensor (114) and a pressure alarm (115) are sequentially arranged on the pressure stabilizing pipeline (111).

8. The condensate pump intelligent flow self-regulating system according to claim 1 is characterized by: A pump inlet valve (6) is installed on the connecting pipeline (5).

9. The condensate pump intelligent flow self-regulating system according to claim 1, characterized in that: The water outlet of the pump body (101) of the condensate pump (1) is connected to a water outlet pipeline (7), and a check valve (8) and a pump outlet valve (9) are installed on the water outlet pipeline (7).

10. The condensate pump intelligent flow self-regulating system according to claim 1, characterized in that: A pressure control valve (10) is installed on the output end of the pressure balance pipeline (3) which is connected to the pump body (101) of the condensate pump (1).

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