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A drainage pump is a pump used to remove water that has accumulated in a work area (such as underground work), thereby preventing the water level there from rising. Such water pumps are often installed around construction pits to lower the groundwater level and prevent groundwater from intruding into the construction site. Working principle of the water pumping unit: Water, which acts as the working medium under certain pressure, is ejected at high speed through nozzles; this converts the pressure of the water into mechanical energy. The gas inside the chamber is forced to be carried away by this accelerated flow, thereby reducing the pressure in that chamber and creating a vacuum. This vacuum then mixes with the groundwater being pumped out, allowing for energy exchange between them. The mixed water enters the diffuser tube where its velocity is reduced and pressure is increased; thereafter, it is pumped out through the vacuum pump’s exhaust pipe back into the water tank, and when the tank is full, it is discharged through the pipes. Uses and features: In construction projects, to keep the excavated soil dry, vacuum pump systems for well point dewatering are commonly used to lower the groundwater level. A certain number of wellpoint pipes are installed before the excavation of the foundation pit. A jet vacuum pump is used to draw down the groundwater level to a lower point, ensuring that the foundation pit remains dry and allowing construction to proceed smoothly. The wellpoint dewatering system, which consists of jet vacuum pump units and well pipes for light wellpoint dewatering, can effectively lower the groundwater level during foundation excavation, prevent slope collapse, avoid water from seeping into the excavation site, and ensure the smooth progress of construction. It is widely used in wellpoint dewatering projects in industries such as construction. Light-duty liquid lift pump units are vacuum-powered devices for pumping liquids, and can also be used in various applications such as mixed absorption and transportation that meet their operational requirements. 1. The jet pump for well point dewatering utilizes fluid to transfer energy; it features a simple structure, reliable operation, low weight and noise level, easy maintenance, and a long service life. 2. The well point dewatering pumps are small in size and compact in structure, making them easy to install. Both the floor mats and pipes are made of galvanized materials, which offer greater corrosion resistance compared to ordinary steel. Welded elbows are used for all connections, resulting in a longer lifespan compared to threaded elbows. 3. The new type of pump units for water reduction utilize a modern design, resulting in lower energy consumption and higher efficiency. Lightweight equipment: It can enter narrow construction sites and can be placed at greater depths, which is advantageous for trench excavation. Good performance: At relatively low water temperatures, an extreme vacuum of 745 mmHG (0.098 MPa) can be achieved, with a pumping depth of up to 9.6 meters; however, the excavation depth increases accordingly. Reliable operation: Apart from the motors in the unit, which are standard products, the other equipment components are easy to replace; (there are no mechanically moving parts in this unit), so failures are unlikely to occur. Usage requirements: It must be placed firmly on a stable foundation in the field, and no debris is allowed to enter the water tank. When used outdoors, it should be placed in a shelter to prevent rising temperatures or freezing. The use of the entire wellpoint dewatering system takes place under vacuum; it must be properly sealed, otherwise efficiency will be significantly reduced. When in use, first close the water inlet valve of the unit to fill the water tank with water. The centrifugal pump should start operating smoothly, and the water pressure must meet the required standards. It is possible to determine whether the operation is normal by considering the achieved ultimate vacuum level, the atmospheric pressure at that time, and the operating water temperature. Then fully open the valve and put the system into operation. The layout of the dewatering system and the well pipes in wellpoint dewatering is determined by the size of the foundation pit, the soil conditions at depth, the level of the groundwater table, as well as the desired depth of dewatering. At the beginning of operation, the vacuum level is low but the drainage volume is high; this volume is closely related to the depth of water absorption. Then the displacement decreases, the vacuum level increases, and the groundwater level drops. Under normal conditions, the vacuum level of the unit can indicate the water level at the well point during precipitation, that is, the vertical distance from the unit’s inlet; for example, if the vacuum level is 450 mmHg (0.06 MPa), the water level is approximately 6 meters. After the well points are cleaned with high-pressure water guns, yellow sand is poured in so that the filter pipes are buried in the sand; the length of the well point pipes is determined based on the requirements for water level reduction. If the filter pipe is used again, the damaged filter screen must be replaced with one of the same specification. Common faults of the unit include a decrease in vacuum level or backflow of water. It is possible to check the operating pressure of the centrifugal pump, examine whether there are any blockages or leaks in the entire system, and check for wear on the water jet pump.