The reason for the decrease of the efficiency of the double suction pump

1、由于水流的冲刷，水泵流道内壁和叶轮过水面变得粗糙不平，水泵内流道的摩阻系数增大，再加上水在泵内的流速很大，水头损失增加。水力效率降低。

1. Due to the erosion of water flow, the inner wall of the pump channel and the impeller of the impeller become rough and rough. The friction coefficient of the flow channel inside the pump increases, and the flow velocity in the pump is great, and the loss of the head is increased. The hydraulic efficiency is reduced.

2、由于在泵前投加药物或水质等原因，使泵壳内严重积垢或腐蚀。泵壳内积垢严重的可以使泵壳壁厚增加2ram左右，而且水泵内壁形成垢瘤，使泵体容积缩小、抽水量减少、并且流道粗糙，水头损失增加。客积效率和水力效率都降低。

2, due to the injection of drugs or water before the pump and other reasons, the pump shell seriously fouling or corrosion. The inner wall thickness of the pump shell can increase the thickness of the pump shell by 2ram, and the inner wall of the pump forms a scale tumor, which reduces the volume of the pump body, reduces the pumping amount, and the flow path is rough and the head loss increases. Both efficiency and hydraulic efficiency are reduced.

3、由于水泵加工工艺造成的铸造缺陷、汽蚀、磨蚀、腐蚀和化学浸蚀等原因造成泵流道内产生空洞或裂缝，水流动时产生旋涡而造成能量损失。水力效率降低。

3. Because of the foundry defects, cavitation, abrasion, corrosion and chemical erosion caused by the processing technology of the pump, there are holes or cracks in the pump flow path, and the flow of the flow produces whirlpool and causes the loss of energy. The hydraulic efficiency is reduced.

4、叶轮表面的汽蚀。由于叶片背水面运行时产生负压，当压力Pk<Pva时，产生汽穴和蜂窝表面后，在电化学腐蚀作用下，使泵叶汽蚀。

4. The cavitation of the surface of the impeller. The negative pressure is generated when the blade is running back to the water surface. When the pressure is Pk<Pva, the cavitation and honeycomb surface are generated, and the corrosion of the pump leaves is caused by electrochemical corrosion.

5、容积损失和机械损失。由于泵使铜钟 一次性止血带 标志桩模具 钢丝轮 流水槽模具 防撞墙模具 检查井钢模具 不锈钢铸件 模锻件用时间长，机械磨损产生漏失和阻力增大，使容积效率和机械效率降低。

5, volume loss and mechanical loss. Due to the long service life of the pump, the wear and tear of mechanical wear increase and the resistance increases, resulting in the reduction of volumetric efficiency and mechanical efficiency.

以上原因，使水泵性能变差。运行效率降低2～5%，严重的可以使水泵效率降低10%以上。