Under the actual operating conditions, it is often necessary to match the specific lift of the existing centrifugal oil pump with the changing operating conditions under the condition that the revolutions remain unchanged. The problem involves not only raising the head but also lowering the field range. Of course, lifting lift can only be done to a small extent and under limited conditions with existing parts. If the round thickness of the impeller mouth is still complete, the Angle and head can be slightly increased by sharpening one side of the blade end. Cutting the impeller with a lathe to reduce head is essentially an efficient method, although there must be varying degrees of turning range depending on the shape of the impeller for efficiency. In the mass production of centrifugal heat conduction pumps, the possibility of changing the head is also widely used in order to obtain as large a working range as possible with the same type of parts.
Pump if the regulating wheel, only turning blade, and not turning impeller cover plate, so that no interference to the oil into the regulating wheel runner, which is very advantageous. If, for example, the guide device is used in the volute, the cover plate of the impeller can also play a better water guide role without turning, and its head is greater than the head of the cover plate. Pumps are less efficient, though. Because the eyeplate shaking increases the power consumption, its impact is greater than the good water conduction action obtained by the head. Therefore, when the impeller runs in the volute without guide vanes, the cover plate must be turned together.
When the impeller diameter is reversed from D2 to D3, not only the head is reduced due to the decrease of the absolute velocity and the cross-sectional area of the exit, but also the flow velocity is reduced. When determining the new diameter corresponding to the head H1 and flow sense Q, the head and flow plate can be approximately intersected with the horizontal aspect of the outlet diameter under the condition that the outlet Angle is roughly the same and the width of the impeller outlet gas is unchanged.
