Intelligent flow self-adjusting system of condensate pump

Abstract

The application relates to an intelligent flow self-regulating system of a condensate pump, which is provided with an input port and an output port on a flash tank, and a condensate collector is connected to the input port of the flash tank; the condensate pump is provided with a water inlet and a water outlet on a pump body, and the water inlet of the pump body is connected to the output port of the flash tank through a communication pipeline; the pressure balance pipeline is provided with two output ends, one of the output ends of the pressure balance pipeline is communicated with the pump body of the condensate pump, and 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; a control module is used for collecting the liquid level height of the flash tank, and the condensate pump is controlled to start after the liquid level height of the flash tank and the center height of the impeller of the pump body reach a predetermined liquid level difference, and the flow of the condensate pump is controlled based on a flow function. The application has the effect of realizing intelligent flow self-regulation of the condensate pump.

Description

Technical Field

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

[0002] Condensate pumps are widely used in petrochemical, power, chemical fiber, and chemical industries where condensate circulation is required. The working principle of a condensate pump is to extract condensate from the condenser using a specific mechanical structure. Condensate pumps typically employ a vertical, cylindrical, double-shell structure. The first stage is either single-suction or double-suction, while the secondary impeller is the same as the final stage impeller and is single-suction. This design allows the condensate pump to effectively extract condensate from the condenser and ensures stable operation under vacuum conditions.

[0003] Domestic scholars have conducted extensive research on condensate pumps, mainly focusing on aspects such as condensate pump outlet pressure pulsation, internal unstable flow, and motor vibration. In the paper "Influence of Long and Short Blade Structure on Condensate Pump Outlet Pressure Pulsation Characteristics" (2022), Hu Jiang used numerical simulation to study the influence of different long and short blade structures on the condensate pump outlet pressure pulsation characteristics. He found that the pump with a 3-long-3-short blade structure exhibited more pronounced and complex outlet pressure pulsation at 1.4Q. d Under flow conditions, the pump outlet pipe exhibits multi-frequency excitation of pressure pulsation characteristics. In the paper "Study on Unsteady Cavitation Characteristics of Condensate Pumps" (2021), Wang Xing used a combination of experimental and numerical simulation methods, employing the renormalization group (RNG) k-ε turbulence model and the Zwart-Gerbe-Belamri cavitation model to simulate the flow inside the pump. He discussed the impact of cavitation on the pump's unstable radial force and blade load, finding that the average radial force significantly increases during the transition from the initial cavitation state to the hypercavitation state. In the paper "Diagnosis and Treatment of Vibration Faults in Vertical Condensate Pump Motors" (2021), Gao Lijun, through a case study, pointed out the serious impact of excessive vibration on the normal operation of turbine generator sets. After a series of causal analyses of motor vibration, various measures were taken to solve the problem, including strengthening the test foundation and dynamic balancing of the rotor. Through in-depth diagnosis, it was found that the root cause of excessive motor vibration lies in the problem of the motor's magnetic field center. It can be observed that most of the existing publicly available papers on condensate pumps focus on the impact of the pump's structure on outlet pressure and internal flow, without delving into the characteristics of the condensate pump system.

[0004] Regarding the aforementioned technologies, the inventors believe that current condensate pumps cannot achieve self-regulation of flow rate, and therefore there are certain areas for improvement. Summary of the Invention

[0005] To achieve intelligent self-regulation of condensate pump flow, this application provides an intelligent self-regulation system for condensate pump flow.

[0006] A condensate pump intelligent flow self-regulating system includes a condensate pump, a flash tank, a pressure balancing pipeline, and a control module;

[0007] The flash tank has an inlet and an outlet, and a condensate collector is connected to the inlet of the flash tank.

[0008] The pump body of the condensate pump has an inlet and an outlet, and the inlet of the pump body is connected to the outlet of the flash tank through a connecting pipe.

[0009] The pressure balancing pipeline has two output ends. One of the output ends of the pressure balancing pipeline is connected to the pump body of the condensate pump, and the other output end of the pressure balancing pipeline is connected to the flash tank. The pressure balancing pipeline is used to introduce inert gas into the pump body of the condensate pump and the flash tank.

[0010] 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 rate of the condensate pump based on the flow function.

[0011] Preferably, in controlling the flow rate of the condensate pump based on the flow function, the control module calculates the flow rate according to the energy equation formula, which is as follows:

[0012] H1+p1 / ρg+v1 2 / 2g=H2+p2 / ρg+v2 2 / 2g;

[0013] In the formula, H1 is the liquid level height of the flash tank, H2 is the center height of the pump impeller, p1 is the gas pressure of the flash tank, p2 is the gas pressure at the center of the pump, v1 is the liquid surface velocity of the flash tank, v2 is the outlet velocity of the pump, g is the acceleration due to gravity, and ρ is the density. Among them, the liquid surface velocity of the flash tank v1 = 0.

[0014] The pressure balancing pipeline is used to introduce inert gas into the pump body of the condensate pump and the flash tank, controlling the gas pressure in the flash tank to be consistent with the gas pressure at the center of the pump body. After converting the energy equation formula, the flow function can be obtained, and the formula of the flow function is as follows:

[0015]

[0016] In the formula, Hz is the liquid level difference between the flash tank and the impeller center height of the condensate pump, Q1 is the flow rate of the flash tank, Q2 is the flow rate of the condensate pump, and A2 is the flow area of ​​the condensate pump.

[0017] Preferably, the inert gas is nitrogen.

[0018] Preferably, the two output ends of the pressure balancing pipeline are respectively connected to the flash tank and the pump body of the condensate pump via lip seals.

[0019] Preferably, the flow rate of the inert gas introduced into the pressure balancing pipeline is 15-30 NL / h.

[0020] Preferably, a pressure stabilizing device is connected to the pressure balancing pipeline.

[0021] Preferably, the pressure stabilizing device includes a pressure stabilizing pipeline 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.

[0022] Preferably, a pump inlet valve is installed on the connecting pipeline.

[0023] Preferably, the outlet of the condensate pump body is connected to a water outlet pipe, and a check valve and a pump outlet valve are installed on the water outlet pipe.

[0024] Preferably, a pressure control valve is installed on the output end of the pressure balancing pipeline that connects to the pump body of the condensate pump.

[0025] In summary, this application includes at least one of the following beneficial technical effects:

[0026] 1. The condensate pump in this application automatically adjusts the delivery flow rate based on the flow function through an intelligent flow self-regulation system. It has a high degree of intelligence and does not require any pressure, level, or throttling instrument control design. Furthermore, it does not require a condensate collection gas-liquid separation storage tank or a frequency converter control system.

[0027] 2. In this application, by introducing inert gas into the pump body of the condensate pump, the NPSHr concept of conventional condensate pumps is changed, and the vaporized medium is transported during operation without cavitation.

[0028] 3. In this application, when the condensate pump is at zero flow, conventional condensate pumps do not have liquid to carry away the heat of the pump body. However, nitrogen gas is introduced into the pump body of the condensate pump through a pressure balancing pipeline. The heat from dry friction can be cooled by nitrogen gas, thereby improving the service life of the condensate pump. Attached Figure Description

[0029] Figure 1 This is the adjustment flowchart of the intelligent flow self-regulating system for condensate pumps.

[0030] Figure 2 This is a system block diagram of a condensate pump intelligent flow self-regulation system.

[0031] Figure 3This is a schematic diagram of a voltage stabilizing device.

[0032] Explanation of reference numerals in the attached drawings: 1. Condensate pump; 101. Pump body; 102. Motor; 2. Flash tank; 3. Pressure balancing 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 Implementation

[0033] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0034] A smart flow self-regulating system for condensate pump 1, referring to Figure 1 and Figure 2 As shown, it includes a condensate pump 1, a flash tank 2, a pressure balancing pipeline 3, and a control module.

[0035] The flash tank 2 has an inlet and an outlet. The inlet is located at the top of the flash tank 2, and the outlet is located at the bottom of the flash tank 2. A condensate collector 4 is connected to the inlet of the flash tank 2. The condensate collector 4 is used to connect to each steam device to collect the condensate generated by each steam device and continuously store it in the flash tank 2.

[0036] The condensate pump 1 includes a pump body 101 and a motor 102 connected to the pump body 101. The pump body 101 has an inlet and an outlet. The inlet of the pump body 101 is connected to the outlet 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.

[0037] The bottom of the pump body 101 is on the same horizontal line as the bottom of the flash tank 2. A water outlet pipe 7 is connected to the outlet of the pump body 101. A check valve 8 and a pump outlet valve 9 are installed on the water outlet pipe 7 in sequence. The pump outlet valve 9 is used to control the opening and closing of the water outlet pipe 7. The check valve 8 is used to prevent the water in the water outlet pipe 7 from flowing back and to ensure that the water flows in one direction in the water outlet pipe 7.

[0038] 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. The connection point between the pressure balancing pipeline 3 and the flash tank 2 is located above the inlet 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.

[0039] It is worth noting that one output end of the pressure balancing pipeline 3 is connected to the pump body 101 of the condensate pump 1 via a lip seal, and the other output end of the pressure balancing pipeline 3 is connected to the flash tank 2 via a lip seal. A pressure control valve 10 is installed on the output end of the pressure balancing pipeline 3 connected to the pump body 101 of the condensate pump 1. The pressure control valve 10 is used to control the opening and closing of the pressure balancing pipeline 3 and the pump body 101 of the condensate pump 1.

[0040] In one embodiment, nitrogen is used as the inert gas, but other inert gases may also be used. This embodiment uses nitrogen as the inert gas for explanation.

[0041] Reference Figure 3 As shown, a pressure stabilizing device 11 is connected to the pressure balancing pipeline 3. 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 entering the pressure balancing pipeline 3 is 15-30 NL / h, preferably 20 NL / h.

[0042] 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, and the output end of the pressure stabilizing pipeline 111 is connected to a pressure balancing pipeline 3. 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.

[0043] The high-pressure inert gas in the gas storage tank is reduced in pressure by the pressure reducing valve 112 and then reaches the needle valve 113. The flow rate of the inert gas can be precisely 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 15 NL / h. The flow sensor 114 is used to monitor the flow rate of the inert gas in the pressure stabilizing pipeline 111. If the flow sensor 114 reaches the maximum value at the minimum flow rate, it indicates that there is a leak in the pressure stabilizing pipeline 111. The pressure alarm 115 is used to monitor the abnormal pressure value in the pressure stabilizing pipeline 111 to prevent the pressure in the pressure stabilizing pipeline 111 from being too high or too low.

[0044] A liquid level sensor is installed inside the flash tank 2. The liquid level sensor is used to collect the liquid level height inside 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. 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, the module controls the condensate pump 1 to start and controls the flow rate of the condensate pump 1 based on the flow function.

[0045] Specifically, the control module controls the flow rate of condensate pump 1 based on the flow function, and calculates the flow rate according to the energy equation formula, which is as follows:

[0046] H1+p1 / ρg+v1 2 / 2g=H2+p2 / ρg+v2 2 / 2g;

[0047] In the formula, H1 is the liquid level height of flash tank 2, H2 is the impeller center height of pump body 101, p1 is the gas pressure of flash tank 2, p2 is the gas pressure at the center of pump body 101, v1 is the liquid surface velocity of flash tank 2, v2 is the outlet velocity of pump body 101, g is the acceleration due to gravity, and ρ is the density. Among them, the liquid surface velocity of flash tank 2 is v1 = 0.

[0048] The pressure balancing line 3 is used to introduce inert gas into the pump body 101 of the condensate pump 1 and the flash tank 2, controlling the gas pressure in the flash tank 2 to be consistent with the gas pressure at the center of the pump body 101, that is, controlling p1 = p2. Therefore, according to the energy equation, the flow velocity within the pump body 101 of the condensate pump 1... After transforming the energy equation, we can obtain the flow function, which is shown in the following formula:

[0049]

[0050] In the formula, Hz is the liquid level difference between the liquid level height of flash tank 2 and the impeller center height of condensate pump 101, Q1 is the flow rate of flash tank 2, Q2 is the flow rate of condensate pump 1 101, and A2 is the flow area of ​​condensate pump 1 101.

[0051] Therefore, the flow rate of flash tank 2 and the flow rate of condensate pump 1 body 101 change with the liquid level difference Hz between the liquid level height of flash tank 2 and the impeller center height of condensate pump 1 body 101. When the liquid level difference Hz approaches zero, the flow rate of condensate pump 1 body 101 also approaches zero.

[0052] In summary, the self-regulating flow system of the condensate pump 1 using this application has the following beneficial effects:

[0053] 1. The condensate pump 1 in this application will automatically adjust the delivery flow based on the flow function through an intelligent flow self-regulation system. It has a high degree of intelligence and does not require any pressure, liquid level, throttling or other instrument control design. It also does not require a condensate collection gas-liquid separation storage tank or a frequency converter or other control system.

[0054] 2. In this 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 cavitation.

[0055] 3. In this application, when the condensate pump 1 has zero flow, the conventional condensate pump 1 does not have liquid to carry away the heat of the pump body 101. Instead, nitrogen gas 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 nitrogen gas, thereby improving the service life of the condensate pump 1.

[0056] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A smart flow self-regulating system for condensate pumps, characterized in that, It includes a condensate pump (1), a flash tank (2), a pressure balancing pipeline (3), and a control module; The flash tank (2) has an inlet and an outlet, and a condensate collector (4) is connected to the inlet of the flash tank (2); The condensate pump (1) has an inlet and an outlet on its pump body (101), and the inlet of the pump body (101) is connected to the outlet of the flash tank (2) through 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). 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). The control module is used to collect the liquid level height of the flash tank (2), and after the liquid level height of the flash tank (2) and the impeller center height of the pump body (101) of the condensate pump (1) reach a predetermined liquid level difference, it controls the condensate pump (1) to start, and controls the flow rate of the condensate pump (1) based on the flow function. The control module controls the flow rate of the condensate pump (1) based on a flow function, and calculates the flow rate according to the energy equation formula, which is as follows: H1+p1 / ρg+v1 2 / 2g=H2+p2 / ρg+v2 2 / 2g; In the formula, H1 is the liquid level height of the flash tank (2), H2 is the impeller center height 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 velocity of the flash tank (2), v2 is the outlet velocity of the pump body (101), g is the gravitational acceleration, ρ is the density, and the liquid surface velocity of the flash tank (2) is v1=0; 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) to control the gas pressure in 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, the 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 condensate pump (101). The flow rate of the flash tank (2) The flow rate of the condensate pump (1) body (101) is... The flow area of ​​the pump body (101) of the condensate pump (1) is the flow area.

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

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

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

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

6. The intelligent flow self-regulating system for a condensate pump according to claim 5, characterized in that: The pressure stabilizing device (11) includes a pressure stabilizing pipeline (111), which is connected to the pressure balancing pipeline (3). The pressure stabilizing pipeline (111) is provided with a pressure reducing valve (112), a needle valve (113), a flow sensor (114), and a pressure alarm (115) in sequence.

7. The intelligent flow self-regulating system for a condensate pump according to claim 1, characterized in that: A pump inlet valve (6) is installed on the connecting pipeline (5).

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

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

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