High Temperature Resistant Centrifugal Pump Installer
The method of filling liquid before starting stainless steel centrifugal pump

2021/09/14

When the stainless steel centrifugal pump starts up, if there is gas in the pump, because the density of the air is small, the centrifugal force produced is also relatively small, at this time the center of the centrifugal impeller can only produce a relatively small negative pressure, and can not absorb the liquid, it will produce the centrifugal impeller idling, destroying the stainless steel centrifugal pump. In order to prevent this air binding phenomenon, in addition to the centrifugal impeller immersed in water centrifugal pump and self-priming pump, generally before starting the pump must be filled with water, also known as water diversion. There are two methods of filling water and exhaust with stainless steel centrifugal pump:

One is to pour water directly into the pump (the venting hole should be opened at this time to drain the gas in the pump), and the second is to pump the gas out of the pump to establish the corresponding vacuum (turn off the drain gate valve at this time) and lead the water into it.

(1) install valves to fill water at the inlet and outlet. This specific method is to install a valve in the inlet pipe, which can be filled with water into the pump after connecting the pipe.

(2) filling water with manual pump. Some centrifugal pumps have hand pumps by themselves, and you can also buy or make miniature hand pumps and assemble them in the inlet pipe. Be sure to assemble the gate valve. After closing the valve, first pour a small amount of water into the water press to draw water, and so on after the hand pressure pump out of the water, it shows that the centrifugal pump has been filled with water and can start operation.

(3) exhaust and irrigation with the help of vacuum equipment. Centrifugal pump self-exhaust and vacuum pump negative pressure exhaust is the same principle, so with the help of water ring vacuum pump exhaust to achieve the effect of filling and diverting water.



The centrifugal pump runs with the help of the rotation of the centrifugal impeller to make the aquatic products move centrifugally. Before starting, the centrifugal pump must be filled with water in the pump shell and suction pipe, and then start the motor, so that the pump shaft drives the centrifugal impeller and water to rotate at a high speed, and the aquatic product centrifugal movement is thrown to the outer edge of the centrifugal impeller. the pressure pipe of the centrifugal pump is injected through the flow channel of the volute pump shell. However, centrifugal pumps also need to be irrigated before use. TEFLOW editor shares several specific irrigation methods, which water supply users choose:

1. Artificial irrigation method: for small pumping stations with a diameter less than 300mm, the inlet pipe is usually equipped with a pump bottom valve. For the micro-pumping station whose inlet pipe diameter is less than 300mm, there is usually a pump bottom valve at the inlet of the inlet pipe, and water can be poured into the pump from the drainage outlet of the centrifugal pump (the pumping station with a short drainage outlet). Because there is no need to purchase other irrigation equipment, this method of irrigation is very common in the current rural micro-pumping stations. For small pumping stations without pump bottom valve, rear stop valve and short pipe, we can also use one side to start, and the other side from the outlet to the centrifugal pump, so that the gas in the centrifugal pump and pipeline is gradually exported, usually after continuous irrigation for a few minutes. The centrifugal pump can operate normally.

2. Vacuum tank irrigation method: for micro pumping stations without pump bottom valve, vacuum tank irrigation 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 inlet pipe, the installation position of the water tank should be as close to the centrifugal pump as possible, and the height of the bottom of the water tank should be slightly lower than the axis of the centrifugal pump. The height of the vacuum tank is generally twice the diameter of the tank. Fill up the water tank to seal it before you begin. After the centrifugal pump starts, the centrifugal pump enters the water from the vacuum tank. When the water level of the water tank drops, the water in the water tank produces a corresponding vacuum. This specific irrigation method has the following advantages: small hydraulic loss, high efficiency of pumping station, low labor intensity of technicians, easy to start, and conducive to the completion of automatic control of centrifugal pump units.

3. Injection pump irrigation method: when the centrifugal pump is pumped by a diesel engine, the exhaust from the diesel engine can be pumped into the injection device connected to the top of the centrifugal pump. When the centrifugal pump starts, the bonnet connected to the handle is closed, the exhaust is ejected from the jet, and the pump is drawn from the pipe. After irrigation, open the bonnet and close the control valve. One of the advantages of this irrigation method is to make full use of the motor to improve the efficiency of the pumping station.

4. Manual pump irrigation method: as a reciprocating volume pump, manual pump is widely used in rural areas. Farmers can use their own manual pump as vacuum pump and centrifugal pump for irrigation, which is both convenient and economical.

5. tap water diversion method: for the semi-submerged pump room (that is, the pumping station with intake pipe and the pump head below the water surface are raised into the pool), the water can be introduced into the centrifugal pump without artificial irrigation. The disadvantage of the pumping station is that the suction capacity of the centrifugal pump is not fully utilized and the assembly height of the centrifugal pump is reduced, which not only increases the excavation of the foundation, but also makes the operation and management inconvenient.

6. Self-suspended water diversion irrigation method: it is completed by the principle of "water-gas replacement" with the help of the bulk density difference between water and gas. This method can remove the pump bottom valve of the centrifugal pump. The first step is to design a suitable container air exchange tank, which is generally made of plastic or thin iron leather, at a cost of only 1/2 of the pump bottom valve. Then, the air exchange tank is installed at the inlet pipe of the centrifugal pump to produce a connection with the centrifugal pump and the pipe. At the same time, an air exchange control valve is assembled on the air exchange channel between the air exchange tank and the centrifugal pump. When filling water, fill the air exchange tank with water in advance, then cover and seal it, and then open the air exchange valve. After ventilation, turn off the air valve and part of the diversion water will be suspended in the intake pipe. According to this specific method repeated several times, all the gas will be discharged, and the inlet pipe will be filled with water. At this point, you can start the centrifugal pump to carry out the lifting operation. Before stopping, as long as you close the gate valve and then stop, the water diversion will not sit back. The next time you turn it on, you won't have to draw water again.
   

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