Multi-stage centrifugal pump

Abstract

The invention relates to a multi-stage centrifugal pump comprising a pump body, a rotating shaft, a first impeller, a second impeller, a third impeller and a switching mechanism. The rotating shaft is connected in the pump body in a rotating mode. The first impeller, the second impeller and the third impeller are sequentially and fixedly connected to the rotating shaft from left to right. The left side of the first impeller and the pump body form a first water suction port, and the right side of the first impeller and the pump body form a first water outlet. The left side of the second impeller and the pump body form a second water suction port, and the right side of the second impeller and the pump body form a second water outlet. The left side of the third impeller and the pump body form a third water suction port, and the right side of the third impeller and the pump body form a third water outlet. An inlet A communicating with the first water suction port is formed in the left side of the pump body. An outlet B is formed in the right side of the pump body. By arranging the switching mechanism, the stage numbers of the impellers can be automatically adjusted according to the actual use working condition, the lift of the multi-stage centrifugal pump is changed, energy consumption is reduced, and cost is saved; and the number of the valid working impellers is changed through mechanical transmission, switching is easy, time is saved, and work is stable.

Description

technical field [0001] The invention belongs to the technical field of fluid pumps, in particular to a multistage centrifugal pump. Background technique [0002] Centrifugal pumps work by rotating the impeller to cause the liquid to undergo centrifugal motion. Its working principle is: when the liquid enters the pump casing, due to the gradual expansion of the flow channel in the volute-shaped pump casing, the flow rate of the liquid gradually decreases, and part of the kinetic energy is transformed into Static pressure energy, so the liquid flows out along the discharge port at a higher pressure. At the same time, a certain vacuum is formed at the center of the impeller due to the liquid being thrown out, and the pressure at the liquid surface is higher than that at the center of the impeller. Therefore, the liquid in the suction line enters the pump under the action of the pressure difference, the impeller rotates continuously, and the liquid is continuously sucked and pr...

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Problems solved by technology

[0003] Multi-stage centrifugal pumps generally have the problem of "big horses and small carts" in actual work. This is due to the unreasonable flow and head of the equipment selected during design and selection or changes in process conditions, resulting in the additional head of the centrifugal pump. The margin is too large, the operating efficiency is low, and the power consumption is large

Generally, technical transformation is carried out by reducing the number of impellers, but this method is complicated to disassemble and take a long time, and the centrifugal pump is prone to unstable operation after transformation

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