The commonly used adjustment methods for vane pumps inc […]
The commonly used adjustment methods for vane pumps include variable speed adjustment, variable diameter adjustment, variable angle adjustment, variable adjustment and shunt adjustment. The Vickers Vane Pump introduces the characteristics of these five adjustment modes:
First, the speed adjustment
Changing the speed of the pump can change the performance of the pump to achieve the purpose of adjusting the operating point of the pump. This adjustment method is called variable speed regulation.
There are two ways to change the speed of the pump. One is to use a variable speed power unit, and the other is to use a variable speed transmission. The speed of the internal combustion engine can be automatically adjusted according to the load of the load; the method of motor shifting mainly includes frequency conversion, variable resistance, variable voltage, variable capacity adjustment and the like.
Second, the reduction adjustment
Turning the outer diameter of the centrifugal pump or the mixed-flow pump impeller can change the performance of the pump, thereby adjusting the working condition of the pump and expanding the water.
The scope of use of the pump, this adjustment method is called the variable diameter adjustment, also known as turning adjustment or cutting adjustment. Turning adjustment has been widely used in pump manufacturing. In order to expand the range of use of water pumps, single-stage single-suction cantilever centrifugal pumps and double-suction centrifugal pumps manufactured in China, in addition to standard diameter impellers, mostly have one or two variants of impellers (A, B). . If necessary, the unit can also be used to cut the impeller by bicycle to achieve the purpose of adjusting the working condition of the pump.
Third, variable angle adjustment
The axial flow pump has a low lift and a high efficiency zone, and a slight change in the working head causes a significant drop in work efficiency. Both throttle adjustment and turning adjustment are not available for axial pumps. However, the axial flow pump has a large rim for easy installation of adjustable blades. Adjusting the operating point of the axial flow pump by changing the mounting angle of the axial flow pump is called variable angle adjustment.
Fourth, variable valve adjustment
For the pumping device with the gate valve in the outlet pipe, when the gate valve is closed, the pipe characteristic curve becomes steep due to the addition of a local resistance in the pipe resistance. Thus, the operating point moves along the curve of the water pump toward the left side of the flow reduction. The smaller the gate valve is closed, the greater the additional resistance and the smaller the flow. This method of changing the position of the pump operating point by closing the small gate valve is called variable valve regulation or throttle regulation.
Five, shunt regulation
Connect a branch pipe or bypass pipe to the water outlet pipe to extract part of the water flow to change the working condition of the water pump.
Section. The split adjustment works in principle exactly the same as the vane pump working on the branch line. It only exerts the potential of machinery and improves pumping efficiency. However, this adjustment requires an additional pipe, so the economics of the adjustment must first be verified by calculation. This situation is the same as a water pump that supplies water at a different level from the outlet. The axial flow pump unit and the centrifugal pump unit operating in series apply shunt regulation at start-up to avoid overload and vibration of the power unit.