What are the water filling methods of centrifugal pump

Centrifugal pumps (except self-priming pumps) must be filled with water before starting the pump and the inlet pipe, otherwise the pump cannot lift water. After the centrifugal pump is started, no water is often caused by the fact that the air in the pump is not drained and the water is not filled.

There are two main water filling methods before starting: one is to fill water by assembling a bottom valve, which is a one-way valve and installed at the inlet of the water inlet pipe. The disadvantage of this method is that the head loss of the bottom valve is large, which affects the device efficiency of the water pump. The other is water filling without bottom valve. The biggest advantage of this method is energy saving, which can save 10% ~ 15% compared with pump stations with bottom valve. The following describes several centrifugal pump water filling methods for users to choose when running the pump.

■ Self-water diversion and water filling method For semi-submerged pump houses (I. e. pump stations where the elevation of the inlet pipe and the pump top of the pump are both below the water surface of the inlet pool), water can be introduced into the pump by itself without manual irrigation. The disadvantage of this pumping station is that it does not make full use of the water absorption capacity of the pump, and the installation elevation of the pump is reduced, which not only increases the amount of excavation of the foundation, but also inconveniences the operation management; but the advantages are also obvious, that is, it is easy to realize the automation of the pumping station, and the timeliness is strong.

■ Artificial water filling method For small pumping stations with water inlet pipe diameter less than 300mm, a bottom valve is usually provided at the inlet of the water inlet pipe. Generally, artificial water filling method is mostly adopted, I .e. water is filled from a water filling funnel (or an inverted ordinary bottle with the bottom of the bottle removed) at a special water filling vent on the upper part of the water pump shell. For small pump stations with inlet pipe diameter less than 300mm, a bottom valve is usually provided at the inlet of the inlet pipe, and water can also be filled into the pump from the outlet of the pump (pump station with shorter outlet pipe) (public number: pump butler). Since there is no need to purchase other water filling equipment, this water filling method is more common in the current rural small pumping stations.

For small pumping stations without bottom valves, check valves and short pipelines, the method of filling water from the outlet pipe to the water pump can also be adopted while starting, so as to gradually bring out the air in the water pump and the pipeline. Generally, after a few minutes of continuous water filling, the water pump can pump water normally.

■ Vacuum water tank filling method For small pumping stations without bottom valves, vacuum water tank filling method can be used. The vacuum water tank is a closed water tank welded with iron sheet. Its volume is at least 3 times the volume of the water inlet pipe. The installation position of the water tank should be as close as possible to the water pump, and the bottom height of the water tank should be slightly lower than the axis of the water pump. The height of the vacuum water tank is generally 2 times the diameter of the water tank.

Before starting the water pump, fill the water tank with water for sealing. After the water pump is started, the water pump enters the water from the vacuum box. Due to the drop of the water level of the water tank, a certain vacuum is formed in the water tank. The water in the water inlet will enter the water tank through the water inlet pipe under the action of atmospheric pressure, thus forming a water circulation and making the water pump start to operate normally.

■ When the diesel engine is used to drive the water pump to pump water by the jet pump water filling method, the exhaust gas discharged from the diesel engine can be passed into the jet connected with the top of the water pump to pump air and fill water, thus removing the bottom valve of the water pump. When the water pump is started, the valve cover connected to the handle is closed, and the exhaust gas is ejected from the jet, and the air in the pump is sucked out through the connecting pipe. Open the valve cover and close the control valve after filling water. The advantage of this water filling method is to make full use of the power machine, and the other is to improve the efficiency of the pumping station.

Self-suspended water diversion and water filling method The self-suspended water diversion and water filling method is realized by the principle of "water-gas replacement" by using the bulk density difference between water and gas. This method can remove the bottom valve of the water pump. First of all, the design of a proper amount of container ventilation tank, ventilation tank is generally plastic products, can also be thin iron pieces, the cost is only a 1/2 of the bottom valve. Then, the ventilation 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, a ventilation control valve is installed on the ventilation channel between the ventilation tank and the water pump. When filling water, fill the ventilation tank with water in advance, then cover and seal, and then open the ventilation valve. After the ventilation is completed, close the ventilation valve, and a part of the water will be suspended in the water inlet pipe. Repeated several times in this way, the air will be completely drained and the water inlet pipe will be filled with water. At this time, the water pump can be started for pumping operation. Before shutdown, as long as the gate valve is closed before shutdown, the water diversion will not sit back. The next time you start, you won't have to fill the water again. The advantages of this water filling method are low price, easy manufacture, low labor intensity and energy saving.

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

An eccentric tooth-shaped impeller is installed in the cylindrical pump housing 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. Because the impeller is eccentrically installed in the pump casing, the size of the space formed between the water ring and the tooth-like blades is different. When the impeller rotates clockwise, the space between the two blades in the right half of the impeller gradually increases. Under closed conditions, as the air volume increases, the pressure decreases and a vacuum is formed. The air in the water pump and the pipeline passes through the suction pipe. The crescent-shaped suction port on the right side of the pump shell is sucked into the vacuum pump. The space between the two blades in the left half of the vacuum pump impeller is gradually reduced, so the air is compressed, the pressure increases accordingly, and finally the vacuum pump is discharged from the vacuum pump through the crescent-shaped exhaust port on the left side of the vacuum pump housing and enters the water-gas separation box, so that the circulating water taken out is separated and reused. The impeller keeps rotating, the vacuum pump continuously inhale and exhaust, and finally the pump is filled with water.

■ manual pump water filling method as a reciprocating positive displacement pump, manual pump is widely used in rural areas of our country, farmers can use their own manual pump as a vacuum pump, the centrifugal pump for water filling, convenient and economical. The most common usage is: the manual pump is installed on the suction hole of the centrifugal pump or the inlet pipe close to the water pump to pump air and water, making it a tool for filling water when the centrifugal pump is turned on, thereby saving the water pump inlet The bottom valve on the pipeline reduces energy loss and improves the efficiency of the pump device.

■ Self-water diversion and water filling method For semi-submerged pump houses (I. e. pump stations where the elevation of the inlet pipe and the pump top of the pump are both below the water surface of the inlet pool), water can be introduced into the pump by itself without manual irrigation. This pump

The disadvantage of the station is that it does not make full use of the water absorption capacity of the pump, while the installation elevation of the pump is reduced, which not only increases

The amount of excavation of the foundation, and the operation and management is also more inconvenient, but the advantages are also more obvious, that is, easy to achieve the pumping station.

Automation, timeliness is strong.

■ Self-suspended water diversion and water filling method Self-suspended water diversion and water filling method is to use the bulk density difference between water and gas, through the "water gas set

Change "principle to achieve. This method can remove the bottom valve of the water pump.

First of all, the design of a proper amount of container ventilation tank, ventilation tank is generally plastic products, can also be thin iron pieces, the cost is only a 1/2 of the bottom valve. Then, the ventilation 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, a ventilation control valve is installed on the ventilation channel between the ventilation tank and the water pump. When filling water, fill the ventilation tank with water in advance, then cover and seal, and then open the ventilation valve. After the ventilation is completed, close the ventilation valve, and a part of the water will be suspended in the water inlet pipe. Repeated several times in this way, the air will be completely drained and the water inlet pipe will be filled with water. At this time, the water pump can be started for pumping operation. Before shutdown, as long as the gate valve is closed before shutdown, the water diversion will not sit back. The next time you start, you won't have to fill the water again. The advantages of this water filling method are low price, easy manufacture, low labor intensity and energy saving.

■ Vacuum pump water filling method For large and medium-sized pumping stations with inlet pipe diameter greater than 300mm, or pumping stations with high automation requirements, vacuum pumping device is a commonly used water filling equipment. It is assembled by vacuum pumps and other equipment, and most of the vacuum pumps often used in irrigation and drainage stations are water ring vacuum pumps. An eccentric tooth-shaped impeller is installed in the cylindrical pump housing 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. Because the impeller is eccentrically installed in the pump casing, the space between the water ring and the tooth-like blades is different.

When the impeller rotates clockwise, the space between the two blades in the right half of the impeller gradually increases. Under closed conditions, as the air volume increases, the pressure decreases and a vacuum is formed. The air in the water pump and the pipeline passes through the suction pipe. The crescent-shaped suction port on the right side of the pump shell is sucked into the vacuum pump. The space between the two blades in the left half of the vacuum pump impeller is gradually reduced, so the air is compressed, the pressure increases accordingly, and finally the vacuum pump is discharged from the vacuum pump through the crescent-shaped exhaust port on the left side of the vacuum pump housing and enters the water-gas separation box, so that the circulating water taken out is separated and reused. The impeller keeps rotating, the vacuum pump continuously inhale and exhaust, and finally the pump is filled with water.