Multistage vertical centrifugal pumpIt is used in fire protection, domestic water supply of high-rise buildings, circulation of air conditioning units, and cooling water transportation. It is to improve the mechanical energy of the fluid through the impeller by the action of centrifugal force through the impeller, which is used to overcome the loss of mechanical energy along the fluid transportation. However, there are limitations in frequency conversion speed regulation, such as large investment, high protection cost, and when the centrifugal pump variable speed is too large, the operating power will decrease. Commonly used flow adjustment methods include variable speed adjustment, variable diameter adjustment, variable angle adjustment, throttling adjustment, etc. 1. Variable speed adjustment Changing the speed of the pump can change the performance of the pump, so that the working point of the pump can change, which is called variable speed mediation. 2. Variable diameter adjustment After the impeller is turned, the performance of the pump will change according to a certain law, so that the working condition point of the pump will change. We call the method of turning the impeller to change the working point of the water pump as variable diameter adjustment.
3. Variable angle adjustment Changing the installation angle of the blades can change the performance of the pump, so as to achieve the purpose of changing the working condition of the pump. This way of changing the operating point is called variable angle adjustment of the pump. Fourth, throttling adjustment for the water pump device with gate valve installed in the outlet pipeline, the gate valve is closed for a small time, and the local resistance is increased in the pipeline, the pipeline characteristic curve becomes steeper, and the working point moves to the upper left along the Q-H curve of the pump. The smaller the gate valve closes, the greater the increased resistance and the smaller the flow becomes. This method of changing the operating point of the pump by closing the small gate valve is called throttle adjustment or variable valve adjustment. When the small gate valve is closed, the local head loss of the pipeline increases, the characteristic curve of the pipeline system moves to the upper left, and the working condition point of the pump also moves to the upper left. The smaller the gate valve is closed, the greater the local head loss and the smaller the flow rate. It can be seen that throttling regulation not only increases local head loss, but also reduces water output, which is very uneconomical. However, due to its simplicity and ease, it is widely used in small pump devices and pump performance tests. Taiwan is increasingly electric