What are the water filling methods for sanitary pumps ②

■Jet pump water filling method: When the diesel engine is used to drive the water pump to pump water, the exhaust gas discharged from the diesel engine can be used to pass into the jet that communicates with the top of the water pump to pump air and fill water, thereby removing the bottom valve of the water pump. When the water pump is started, the valve cover connected to the handle is closed, the exhaust gas is ejected from the jet, and the air in the pump is sucked out through the connecting pipe. After filling the water, open the valve cover and close the control valve. The advantage of this water filling method is that it makes full use of the power machine, and the other is that it improves the efficiency of the pumping station.

■Self-suspension diversion and water-filling method: The self-suspension diversion and water-filling method uses the difference in bulk density of water and air and is realized through the principle of "water-air replacement". This method can remove the bottom valve of the water pump.

First of all, design a ventilation tank with an appropriate amount of containers. The ventilation tank is generally made of plastic products, but can also be made of thin metal parts, and the cost is only one-half of the bottom valve. Then, the ventilating tank is placed at the water inlet of the water pump to form a communicating body with the water pump and the pipeline. At the same time, install an air exchange control valve on the air exchange channel between the air exchange tank and the water pump. When filling water, fill the air exchange tank with water in advance, then seal it with a cap, and then open the air exchange valve. After the air exchange is completed, close the air exchange valve, and a part of the water will be suspended in the inlet pipe. Repeat this method several times, all the air will be exhausted, and the water inlet pipe will be filled with water. At this point, the water pump can be started for lifting operations. Before shutting down, as long as the gate valve is closed and then shut down, the water diversion will not sit back. There is no need to irrigate and divert water the next time it is started. The advantages of this water-filling method are lower price of the gas exchange tank, easy manufacture, low labor intensity, and energy saving.

■ Sanitary pump water filling method: For large and medium pumping stations with a water inlet pipe diameter greater than 300mm, or pumping stations with high automation requirements, a vacuum pumping device is a commonly used water filling device. It is assembled by vacuum pumps and other equipment. The vacuum pumps often used in irrigation and drainage stations are mostly water ring vacuum pumps.

An eccentric toothed impeller is installed in the cylindrical pump casing of the water ring vacuum pump. The pump casing is filled with circulating water. When vacuuming, the impeller rotates. Under the action of centrifugal force, the circulating water in the pump casing is thrown around the impeller, forming a rotating water ring on the inner wall of the pump casing. And because the impeller is eccentrically installed in the pump casing, the size of the space formed between the water ring and the toothed blades is different. When the impeller rotates clockwise, the space between the two blades on the right half of the impeller gradually increases. Under the closed condition, as the air volume increases, the pressure decreases, forming a vacuum, and the air in the water pump and the pipeline passes through The suction pipe enters the crescent-shaped suction port on the right side of the vacuum pump casing and is sucked into the vacuum pump. The space between the two blades of the left half of the vacuum pump impeller is gradually reduced. Therefore, the air is compressed and the pressure increases, and finally passes through the vacuum pump. The crescent-shaped exhaust port on the left side of the pump casing discharges the vacuum pump and enters the water-gas separation box to separate the circulating water that is carried out before reuse. When the impeller keeps rotating, the vacuum pump continuously sucks and exhausts air, and finally fills the water pump with water.

■Hand pump water filling method: As a kind of reciprocating positive displacement pump, manual pumps are widely used in rural areas of our country. Farmers can use their own hand pumps as vacuum pumps to fill centrifugal pumps with water, which is convenient and economical. The most common usage is: install the hand pump on the suction hole of the centrifugal pump or on the water inlet pipe close to the water pump to pump air and divert water, making it a tool for filling water when the centrifugal pump is turned on, thus eliminating the need for the water pump inlet pipe The bottom valve reduces energy loss and improves the efficiency of the water pump device.