Analysis of Causes of Failure to Supply Water by Centrifugal Water Pump

Centrifugal pumps have become the most widely used type of pumps in agriculture due to their simple structure, ease of use and maintenance, and high efficiency. However, they are also annoying due to the fact that they are sometimes not watered. We will analyze the reasons for the deliberate impediment of the supply of water. There are air in the water inlet pipe and pump body. (1) Some users do not fill enough water before the water pump starts; sometimes it appears that the water poured has overflowed from the air outlet hole, but the air is completely discharged without turning the pump shaft, resulting in a little air remaining In the inlet pipe or pump body. (2) The horizontal section of the inlet pipe in contact with the water pump shall be applied with a descending gradient of more than 0.5% in the direction of the reverse flow, and the end connected to the pump inlet shall be the highest, and shall not be completely horizontal. If it is lifted upwards, air will remain in the inlet pipe, which will reduce the degree of vacuum in the pipes and the water pump, affecting water absorption. (3) The filler of the pump has been worn out for a long time or the packing is too loose, causing a large amount of water to be ejected from the clearance between the packing and the shaft sleeve of the pump shaft. As a result, external air enters the interior of the pump from these clearances. Affected the lifting of water. (4) The water inlet pipe has holes due to long-term potential underwater and corrosion of the pipe wall. After the water pump works, the water surface continues to drop. When these holes are exposed to the water surface, air enters the inlet pipe from the hole. (5) There is a crack at the elbow of the inlet pipe, and there is a slight gap between the inlet pipe and the pump, which may cause air to enter the inlet pipe. Pump speed is too low (1) human factors. A considerable number of users were damaged by the original motor, and they were arbitrarily equipped with another motor. As a result, the result was that the flow rate was low, the lift was low, and the pump was not able to pump water. (2) Wear of the belt. There are many large-scale off-water pumps that use tape transmission. Because of long-term use, the belt is worn and loose, and slipping occurs, which reduces the speed of the water pump. (3) Improper installation. The center distance of the two pulleys is too small or the two axes are not parallel, and the belt is tightly mounted to the top. As a result, the wrap angle is too small, the miscalculation of the diameter of the two pulleys and the eccentricity of the two shafts of the water pump of the coupling drive are large. Change in the speed of the pump. (4) The mechanical failure of the pump itself. The loosening of the impeller or the pump shaft fastening nut or the deformation and bending of the pump shaft causes the impeller to move more and more, directly to the pump body, or the bearing to be damaged, which may reduce the speed of the pump. (5) Power machine maintenance is not recorded. The motor is lost due to the windings burned out, and the number of windings, wire diameters, and wiring methods in the maintenance, or failures in the maintenance that are not completely eliminated will also cause the pump speed to change. Suction lift is too large and some water sources are deep. Some water sources have flat ground at the periphery, and the pump's allowable suction range is neglected, resulting in less water absorption or no suction at all. It should be noted that the degree of vacuum that can be established at the suction port of the pump is limited, and the absolute suction is approximately 10 meters of water column height, and it is impossible for the pump to establish an absolute vacuum. Moreover, if the vacuum degree is too large, the water in the pump is easily vaporized, which is unfavorable to the work of the water pump. Therefore, each centrifugal pump has its maximum allowable suction range, generally between 3 and 8.5 meters. When installing a water pump, it must not only be convenient and simple. The resistance loss in the water flowing into and out of the water pipe is too large. Some users have measured. Although the vertical distance between the reservoir or the water tower and the source water surface is still slightly smaller than the pump lift, the amount of water to be pumped is small or the water is not lifted. The reason is often that the pipeline is too long, the water pipe bends too much, and the resistance loss of the water flow in the pipeline is too large. The reason is often that the pipeline is too long, the water pipe bends too much, and the resistance loss of the water flow in the pipeline is too large. In general, the 90-degree elbow has a greater resistance than the 120-degree elbow. The loss of the head of each 90-degree elbow is about 0.5 to 1 meter. The resistance of each 20-meter pipe can make the head loss about 1 meter. In addition, some users are also free to enter and exit the pipe diameter of the pump, which also has a certain impact on the lift. Influence of other factors (1) The bottom valve cannot be opened. It is usually due to the long time for the pump to stand, the bottom valve gasket is stuck, and the bottom valve without the gasket may rust. 2) The bottom valve filter net is blocked; or the bottom valve is potentially blocked in the sludge layer in the water. (3) The impeller wears badly. Impeller blades wear over a long period of use, affecting the performance of the pump. (4) Failure or blockage of the gate valve or check valve can result in reduced flow or even failure to catch water. (5) The exchange of outflow pipes will also affect the amount of water pumped.

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Product	Cat NO.	Membrane Filter	Pore Size	Sterile	Pack
150 ml Vacuum Filter System	SPE22150	PES	0.22 μm	Gamma	12pcs/ctn
	SPE45150	PES	0.45 μm	Gamma	12pcs/ctn
	SMC22150	MCE	0.22 μm	Gamma	12pcs/ctn
	SMC45150	MCE	0.45 μm	Gamma	12pcs/ctn
	SPV22150	PVDF	0.22 μm	Gamma	12pcs/ctn
	SPV45150	PVDF	0.45 μm	Gamma	12pcs/ctn
	SNY22150	NYLON	0.22 μm	Gamma	12pcs/ctn
	SNY45150	NYLON	0.45 μm	Gamma	12pcs/ctn
250 ml Vacuum Filter System	SPE22250	PES	0.22 μm	Gamma	12pcs/ctn
	SPE45250	PES	0.45 μm	Gamma	12pcs/ctn
	SMC22250	MCE	0.22 μm	Gamma	12pcs/ctn
	SMC45250	MCE	0.45 μm	Gamma	12pcs/ctn
	SPV22250	PVDF	0.22 μm	Gamma	12pcs/ctn
	SPV45250	PVDF	0.45 μm	Gamma	12pcs/ctn
	SNY22250	NYLON	0.22 μm	Gamma	12pcs/ctn
	SNY45250	NYLON	0.45 μm	Gamma	12pcs/ctn
500 ml Vacuum Filter System	SPE22500	PES	0.22 μm	Gamma	12pcs/ctn
	SPE45500	PES	0.45 μm	Gamma	12pcs/ctn
	SMC22500	MCE	0.22 μm	Gamma	12pcs/ctn
	SMC45500	MCE	0.45 μm	Gamma	12pcs/ctn
	SPV22000	PVDF	0.22 μm	Gamma	12pcs/ctn
	SPV45000	PVDF	0.45 μm	Gamma	12pcs/ctn
	SNY22000	NYLON	0.22 μm	Gamma	12pcs/ctn
	SNY45000	NYLON	0.45 μm	Gamma	12pcs/ctn
1000 ml Vacuum Filter System	SPE22000	PES	0.22 μm	Gamma	12pcs/ctn
	SPE45000	PES	0.45 μm	Gamma	12pcs/ctn
	SMC22000	MCE	0.22 μm	Gamma	12pcs/ctn
	SMC45000	MCE	0.45 μm	Gamma	12pcs/ctn
	SPV22000	PVDF	0.22 μm	Gamma	12pcs/ctn
	SPV45000	PVDF	0.45 μm	Gamma	12pcs/ctn
	SNY22000	NYLON	0.22 μm	Gamma	12pcs/ctn
	SNY45000	NYLON	0.45 μm	Gamma	12pcs/ctn

Brief of Membrane

1. 1.PES (polyether sulfone) is high chemical, thermal stabile and has fast-flowing ability, acid and alkali resistant ability ( PH range 1-14), with high mechanical strength.

1. 2.MCE(mixed cellulose esters) is the mixture of cellulose nitrate and cellulose acetate which is hydrophilic, chemical compatible and has a high amount of protein adsorption. Generally, it applies to particle analysis, particle place, biochemical analysis, HPLC sample preparation and solvent filtration.

1. 3.PVDF(polyvinylidene fluoride) has chemical stability and inertness which is applicable to chemically aggressive organic solvents, strong acids and alkali solution and sample preparation of HPLC (high performance liquid chromatography) analysis. It`s hydrophobic to filter off moisture in the air, gases and is laminated on supporting net for its strong strength, operability. Preferably, it`s resistant to a high temperature of 130 degrees.
3. 4.NYLON(organic nylon 66) is applicable in most organic solvents and aqueous solution, for instance, organic solvents of strong acid, 70% ethanol and methylene chloride. It has good strength, chemical stability and high temperature resistant ability.

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Zhejiang Sorfa Medical Plastic Co., Ltd. (Ningbo Jiangdong Aron Imp&Exp. Co.LTD) , http://www.sorfapipettes.com