How to adjust the flow of the pipeline pump

For low and medium specific speed pump, this is one of the most common and low flow regulating method. The method is usually limited to the low specific speed pump in use. Partial closure of the outlet pipe on any form of valve will increase the system pressure head, so the pressure head of the system will be in a smaller flow and the pressure of the pump head curve intersection. The outlet throttling enables the operating point to move to a lower efficiency point and has a power loss at the throttle valve. This is likely to be important for large pump installations, which may be more economical and more attractive. Throttle critical dead may cause overheating of fluid within the pump, to maintain the necessary minimum flow bypass, or by different means of regulation. This is very important for the treatment of hot water or volatile liquid in the front of the pump is very important.

If there is enough NPSH can be used, then in the suction pipeline can save some power through the throttle. Jet fuel pipeline pumps are often used in the jet engine fuel pipeline pump, because the outlet throttle can cause the liquid to overheat or vaporization. In very small flow, the pump impeller only partially filled with liquid. Therefore, input power and temperature rise about export throttling impeller play 1 / 30 of the transposition of the condensate pump flow is usually used submerged to control the depth of 7, which is equivalent to the inlet throttle. Special design can reduce the cavitation damage of these pumps to a small extent, but the energy levels have become quite low.

Discharge all or part of the flow from the [1] of the pipeline pump, through the bypass pipe to the pump suction port or other appropriate point. The bypass can be fitted with one or more flow Kong Banhe suitable control valves. Metering bypass is usually used to reduce the flow of the boiler feed water pump, mainly to prevent overheating. If the excess flow of the bypass propeller pump is used to replace the outlet throttle, considerable power can be saved.

When the flow is regulated by this method, the required power can be reduced to a minimum, and the overheating phenomenon in the process of flow regulation can be excluded. The steam turbine and the internal combustion engine are easy to adapt to the speed adjustment with very little additional cost. A variety of mechanical, magnetic, hydraulic and DC and AC variable speed motor can be used to adjust the speed. Usually, variable speed motor is too expensive, only in the case of special conditions for economic research to prove that it is worth the time to use adjustable blade adjustment.

On the study of the installed in front of the impeller of the adjustable guide vane found that speed =5700 (2.086). This method regulation of the pump is effective. The blades can generate positive pre swirl, thereby reducing the pressure head, the flow rate and the efficiency. And for only the blade to obtain a relatively small regulatory effect. Large energy storage pumps used for power generation in Europe have been successfully applied to the control of outlet diffuser blades. The propeller pump with variable pitch blade was also successfully studied. Under the condition that the efficiency loss is relatively small, the large flow range can be obtained. But these methods are too complex and expensive, so they are limited in practical application.