Aeration tank effluent pump cavitation mitigation device

Abstract

The utility model discloses an aeration tank effluent pump cavitation mitigation device, include: water pump, inlet U type pipe, its inlet end connects the water pipe of aeration tank, its outlet end connects the water inlet pipeline of water pump, the U shape arc top of inlet U type pipe sets up to the top, and its inside installation has the on -off valve, pressure sensor, installs on the water pipeline of water pump, is used for detecting the water pressure, control module, with water pump, on -off valve and pressure sensor signal connection, receives the pressure signal of pressure sensor detection and can control water pump and the action of on -off valve. Compared with prior art, the utility model can alleviate the violent cavitation harm caused by the suction of a large number of accumulated gas in the starting moment, and effectively prevent the idle running risk triggered thereby, ensure the safe, stable start and operation of the water pump.

Description

Technical Field

[0001] This utility model relates to the field of water treatment technology, and in particular to a device for mitigating cavitation in an aeration tank effluent pump. Background Technology

[0002] In the field of water treatment technology, most wastewater treatment systems on-site are equipped with aeration devices in their raw water tanks to prevent the accumulation of suspended solids such as particles in the raw wastewater from affecting the tank's storage capacity and to facilitate regular cleaning. In some wastewater treatment processes, aeration is used to agitate pretreatment reactions such as pH adjustment tanks to accelerate chemical reactions. Furthermore, for example, a plant using anaerobic ammonia oxidation for denitrification has a pretreatment reaction tank in its ammonia-nitrogen-containing raw water, which also contains hydrogen peroxide. This tank removes hydrogen peroxide and adjusts the pH; a small amount of aeration is added to ensure rapid reaction within the limited retention time. In these aeration tank systems, water pumps are the key equipment for transporting the treated water. However, the process characteristics of aeration tanks dictate that their effluent will inevitably contain a large amount of dissolved or undissolved gases.

[0003] Currently, in the connecting pipes from the aeration tank outlet to the pump inlet, especially when the pump is stopped, free gases carried in the water (including residual gases from previous operation and naturally released gases) easily accumulate in the pipes. When the pump restarts, these pre-accumulated gas masses are instantly entrained into the pump body by the high-speed water flow, causing severe pitting and erosion damage to the pump impeller, pump casing, and other flow-through components, significantly shortening the equipment's lifespan. It can also cause the pump to fail to pump, or even completely lose its pumping capacity and enter a dry-running state. Furthermore, the pump's mechanical seals may rapidly fail due to lack of liquid lubrication and cooling, leading to leakage. The rotor components may overheat, deform, or even seize due to frictional heat, affecting the stable operation of the entire system.

[0004] Therefore, there is an urgent need for a device that can discharge the gas accumulated in the pipeline before the water pump is started, thereby reducing the severe cavitation damage caused by the intake of a large amount of accumulated gas at the moment of startup, and effectively preventing the risk of dry running triggered by this, so as to ensure the safe and stable start-up and operation of the water pump. Utility Model Content

[0005] Purpose of the utility model: In view of the problems existing in the prior art, this utility model provides a device to mitigate cavitation of the effluent pump of the aeration tank, which can reduce the severe cavitation damage caused by the intake of a large amount of accumulated gas at the moment of startup, and effectively prevent the risk of dry running triggered by this, so as to ensure the safe and stable startup and operation of the pump.

[0006] Technical solution: This utility model provides a device for mitigating cavitation in an aeration tank effluent pump, comprising: Water pump; The inlet U-shaped pipe has its inlet end connected to the outlet pipe of the aeration tank and its outlet end connected to the inlet pipe of the water pump. The U-shaped arc apex of the inlet U-shaped pipe is set upward. An exhaust branch pipe is vertically connected to the top of the U-shaped arc and has an on / off valve installed inside it. A pressure sensor is installed on the outlet pipe of the water pump to detect the outlet water pressure; The control module is connected to the water pump, the on / off valve, and the pressure sensor. It receives the pressure signal detected by the pressure sensor and can control the operation of the water pump and the on / off valve.

[0007] Furthermore, the water pump is equipped with an inlet control valve on its inlet pipe and an outlet check valve and an outlet control valve are sequentially installed on its outlet pipe.

[0008] Furthermore, the pump's suction port and discharge port are connected to the inlet and outlet pipes respectively via flexible connectors.

[0009] Furthermore, the water pump is provided in two units and is connected in parallel, with each water pump connected to an independent inlet pipe and outlet pipe.

[0010] Furthermore, the outlet pipes of the two water pumps are connected to the main outlet pipe via a tee, and the pressure sensor is installed on the main outlet pipe.

[0011] Furthermore, the straight pipes on both sides of the water inlet U-shaped pipe are set perpendicular to the horizontal plane.

[0012] Furthermore, the exhaust branch pipe has an inlet pipe connected to its outlet end, and the inlet pipe is connected to the main water outlet pipe.

[0013] Furthermore, the opening and closing valve is an exhaust valve.

[0014] Furthermore, the inlet control valve and the outlet control valve are manual valves. Beneficial effects

[0015] 1. This utility model sets up an inlet U-shaped pipe and an exhaust branch pipe. Before the water pump starts, the exhaust valve is opened to discharge the free gas at the top of the U-shaped pipe, which avoids the gas mass being sucked into the pump body and causing severe cavitation. At the same time, the pressure sensor monitors the outlet water pressure in real time. Once the pressure is abnormal, the pump will stop immediately or the exhaust will be linked. The dual protection mechanism effectively prevents impeller erosion, mechanical seal dry running failure and dry running risk, and significantly extends the life of the water pump.

[0016] 2. This utility model improves system redundancy through a dual-pump parallel design. When a single pump fails, the backup pump can be seamlessly switched to ensure continuous operation. The pressure sensor is integrated into the main outlet water pipe to uniformly monitor the output pressure of both pumps.

[0017] 3. In this utility model, the gas discharged from the exhaust branch pipe is guided back to the main water outlet pipe through the inlet pipe, which avoids the waste gas and wastewater being directly discharged to the water pump when necessary. Moreover, when the opening and closing valve is not closed in time due to malfunction or operation delay, the guiding effect of the inlet pipe can force the overflow water flow to the main water outlet pipe, preventing liquid from splashing and leaking from the top of the exhaust branch pipe and avoiding the risk of pollution. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model; Among them, 1-water pump, 2-inlet U-shaped pipe, 3-aeration tank, 4-outlet pipe, 5-vent branch pipe, 6-opening and closing valve, 7-pressure sensor, 8-inlet control valve, 9-outlet check valve, 10-outlet control valve, 11-flexible joint, 12-outlet main pipe, 13-inlet pipe. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings.

[0020] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. Example 1:

[0022] A device for mitigating cavitation in an aeration tank effluent pump includes: Water pump 1; The inlet U-shaped pipe 2 has its inlet end connected to the outlet pipe 4 of the aeration tank 3 and its outlet end connected to the inlet pipe of the water pump 1. The U-shaped arc top of the inlet U-shaped pipe 2 is set upward. The exhaust branch pipe 5 is vertically connected and installed on the top of the U-shaped arc, and an on / off valve 6 is installed inside it. Pressure sensor 7 is installed on the outlet pipe of water pump 1 to detect the outlet pressure; The control module is connected to the water pump 1, the on / off valve 6 and the pressure sensor 7. It receives the pressure signal detected by the pressure sensor 7 and can control the operation of the water pump 1 and the on / off valve 6.

[0023] The water pump 1 has an inlet control valve 8 on its inlet pipe and an outlet check valve 9 and an outlet control valve 10 on its outlet pipe. Optionally, the inlet control valve 8 and the outlet control valve 10 can be manual valves or electric / pneumatic valves. If they are solenoid valves, they are connected to the control module and can be controlled to open and close by the control module.

[0024] The suction port and discharge port of water pump 1 are connected to the inlet pipe and outlet pipe respectively via flexible joint 11, which is used to absorb the vibration and pipe stress during the operation of water pump 1 and prevent the interface from loosening and leaking air.

[0025] The straight pipes on both sides of the water inlet U-shaped pipe 2 are set perpendicular to the horizontal plane to facilitate the accumulation of gas at the top of the U-shaped arc.

[0026] Preferably, the exhaust end of the exhaust branch pipe 5 is connected to an inlet pipe 13, which is connected to the water outlet pipe of the water pump 1. The discharged gas or any possible overflow water will be directed back to the outlet pipe to prevent direct leakage and environmental pollution.

[0027] The on / off valve 6 is an exhaust valve. Preferably, the on / off valve 6 is an electromagnetic exhaust valve, which can receive electrical signals to open and close quickly.

[0028] The control module (including, for example, a programmable logic controller (PLC), a signal input / output module, etc.) and the signal connection method between it and the water pump 1, the on / off valve 6, the pressure sensor 7, and the level sensor (if set) described in this utility model are all implemented using conventional and mature existing technologies in the field of water treatment or industrial automation control.

[0029] The control module connects to existing, commercially available supervisory control and data acquisition (SCADA / HMI) systems or human-machine interfaces. These systems serve only as standardized auxiliary tools for operators to view the device's operating status (such as pressure, liquid level, valve status, and pump status), receive alarm information (such as low pressure alarm LL, pump failure), and set or adjust operating parameters (such as venting time T, pressure alarm thresholds L and LL, and start / stop liquid level thresholds H and L). The functions and uses of these supervisory control and data acquisition systems are standard practices in the field of automation and are not part of or improvements of this utility model.

[0030] When water pump 1 needs to be started, the control module first issues a command to open the on / off valve 6. The on / off valve 6 remains open to perform venting operations for a duration set to T seconds. The value of T needs to be preset in the host computer or control module according to the actual working conditions (such as pipe length, diameter, water gas content, and historical venting effect), and is usually in the range of 5 to 30 seconds. During this period, the gas accumulated in the air chamber at the top of the inlet U-shaped pipe 2 is discharged to the outlet main pipe 12 through the vent branch pipe 5 and the inlet pipe 13.

[0031] After the venting time T ends, the control module issues a command to close the on / off valve 6 and immediately starts the water pump 1. The water pump 1 begins operation, delivering treated water. Simultaneously, the control module continuously reads the outlet water pressure value detected by the pressure sensor 7.

[0032] If the pressure value detected by pressure sensor 7 reaches and stabilizes within the normal operating pressure range (usually significantly higher than the set lower limit L) within a period of time after startup (e.g., 30-60 seconds), it indicates that the water pump has started successfully and is operating normally.

[0033] The control module presets a low pressure threshold L (e.g., 70% of the rated outlet pressure). If, during the operation of pump 1, the pressure value detected by pressure sensor 7 remains below L for a certain period of time (e.g., 5-10 seconds), the control module determines that the pump may be experiencing cavitation due to excessive gas intake, insufficient output, or a risk of idling. In this case, the control module immediately issues a command to stop the currently operating pump 1. For a single-pump system, this will trigger an alarm. For the dual-pump parallel system of Example 2 (see below), the control module will start the other standby pump according to the above steps while stopping the faulty pump.

[0034] The control module also presets a lower emergency pressure threshold LL (e.g., 50% or lower of the rated outlet pressure). If the pressure value detected by pressure sensor 7 drops below the LL value, the control module will immediately trigger a high-level alarm (such as an audible and visual alarm) regardless of whether the L point has been reached or whether the water pump has been switched, prompting the on-duty personnel to intervene and handle the situation immediately.

[0035] The innovation of this utility model lies in the specific combination structure and connection relationship of the hardware device (including the water inlet U-shaped pipe 2, exhaust branch pipe 5, on / off valve 6, pressure sensor 7, etc.) and the method process of using the hardware device to reduce cavitation (such as exhaust before startup), rather than the improvement of the control module hardware or its underlying software and communication protocol itself.

[0036] The logic executed by the control module (such as "open the on / off valve to vent for T seconds before starting the water pump", "stop or switch pumps when the pressure is below the threshold L", and "start / stop pumps based on liquid level H / L") is conventional sequential control and threshold judgment logic set based on the structural characteristics of the device of this utility model. The programming implementation of this type of logic is a routine task that can be completed by those skilled in the art using standard programming methods (such as ladder diagrams and function block diagrams) according to the functional requirements of the device and the above-mentioned explicit steps, and does not involve innovation in the control software itself. Example 2:

[0037] See Figure 1 The structure of this embodiment is roughly the same as that of Embodiment 1, except that: Two water pumps 1 are provided and are set in parallel. The two water pumps 1 are respectively connected to independent inlet pipes and outlet pipes.

[0038] The outlet pipes of the two water pumps 1 are connected to the main outlet pipe 12 via a tee, and the pressure sensor 7 is installed on the main outlet pipe 12. The inlet pipes of the two water pumps 1 are connected to the outlet end of the inlet U-shaped pipe 2 via a tee. Preferably, the tee is an electrically controlled tee, which can be switched via a control module.

[0039] The tee connecting the water pump inlet pipe to the U-shaped pipe outlet, and the tee connecting the water pump outlet pipe to the main outlet pipe 12, both use conventional pipe fittings (such as standard T-type or Y-type tee fittings). Preferably, the tee is equipped with an electrically controlled valve (such as an electric three-way valve). This valve is connected to the control module via a conventional signal line, and the control module sends switching commands according to preset logic (such as synchronously switching the water circuit when switching the operating pump). It should be noted that configuring an electrically controlled three-way valve is an optimization and extension of the device of this utility model using existing automation technology, and its control logic (such as pump-valve linkage) can be implemented by those skilled in the art based on conventional control methods.

[0040] Preferably, the exhaust branch pipe 5 is connected to an inlet pipe 13 at its outlet end. The inlet pipe 13 is connected to the main water outlet pipe 12 to guide the discharged gas or any possible overflow water back to the main water outlet pipe, thus preventing direct leakage and environmental pollution.

[0041] The other structures are the same as in Example 1, and will not be described in detail here.

[0042] Working principle:

[0043] When pump 1 is stopped, free gas in the outlet pipe 4 of aeration tank 3 rises and accumulates at the top of the U-shaped arc in the vertical section of the inlet U-shaped pipe 2. Before the pump starts, the control module first opens the on / off valve 6 on the exhaust branch pipe 5 to discharge the accumulated gas to the main outlet pipe 12 via the inlet pipe 13, eliminating the cause of cavitation. After the pump starts, the pressure sensor 7 monitors the outlet pressure in real time. If a sudden drop in pressure is detected, the control module immediately shuts down the pump to prevent damage from dry running.

[0044] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent transformations or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A device for mitigating cavitation in an aeration tank effluent pump, characterized in that, include: Water pump (1); The inlet U-shaped pipe (2) is connected to the outlet pipe (4) of the aeration tank (3) at its inlet end and to the inlet pipe of the water pump (1) at its outlet end. The U-shaped arc top of the inlet U-shaped pipe (2) is set upward. An exhaust branch pipe (5) is vertically connected to the top of the U-shaped arc and has an on / off valve (6) installed inside it. A pressure sensor (7) is installed on the outlet pipe of the water pump (1) to detect the outlet pressure; The control module is connected to the water pump (1), the on / off valve (6) and the pressure sensor (7), receives the pressure signal detected by the pressure sensor (7) and can control the operation of the water pump (1) and the on / off valve (6).

2. The cavitation mitigation device for an aeration tank effluent pump according to claim 1, characterized in that: The water pump (1) is equipped with an inlet control valve (8) on its inlet pipe and an outlet check valve (9) and an outlet control valve (10) in sequence on its outlet pipe.

3. The cavitation mitigation device for an aeration tank effluent pump according to claim 2, characterized in that: The inlet and outlet of the water pump (1) are connected to the inlet pipe and outlet pipe respectively via flexible connector (11).

4. A device for mitigating cavitation in an aeration tank effluent pump according to claim 1 or 3, characterized in that: The water pump (1) is provided in two units and is set in parallel. The two water pumps (1) are respectively connected to independent inlet pipes and outlet pipes.

5. The cavitation mitigation device for an aeration tank effluent pump according to claim 4, characterized in that: The outlet pipes of the two water pumps (1) are connected to the main outlet pipe (12) via a tee, and the pressure sensor (7) is installed on the main outlet pipe (12).

6. The cavitation mitigation device for an aeration tank effluent pump according to claim 1, characterized in that: The straight pipes on both sides of the water inlet U-shaped pipe (2) are set perpendicular to the horizontal plane.

7. The cavitation mitigation device for an aeration tank effluent pump according to claim 5, characterized in that: The exhaust branch pipe (5) is connected to an inlet pipe (13) at its outlet end, and the inlet pipe (13) is connected to the main water outlet pipe (12).

8. The cavitation mitigation device for an aeration tank effluent pump according to claim 1, characterized in that: The opening and closing valve (6) is an exhaust valve.

9. The cavitation mitigation device for an aeration tank effluent pump according to claim 2, characterized in that: The inlet control valve (8) and outlet control valve (10) are manual valves.

Images