How to control this situation, to ensure both flow and pressure? ?
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How to control this situation, to ensure both flow and pressure? ? As shown in the picture: The outlet of the centrifugal pump is the main water pipe, which is filtered by several filters connected in parallel. Each filter inlet branch pipe is equipped with a flow meter and a valve to control the inlet water flow. The filter outlet enters ultrafiltration, and the ultrafiltration inlet requires a certain pressure such as 0.15MPA. The problem is that in this case, it is necessary to control the inlet water flow stably and control the pressure at the filter outlet (into ultrafiltration) to a certain value. How to control it? How to control it in case of cascade control?
The filter inlet flow control constitutes a secondary loop, and the outlet pressure control constitutes the main loop. Cascade control can provide stable control.
I didn't understand it. . . . .
I don't know what the process characteristics of ultrafiltration and filters are, but it may be necessary to consider the impact of their pressure drop changes on the pressure flow rate.
Filtration is a process in which the pressure increases from small to large, that is, the resistance grows upward, so control is troublesome.
You should first ensure that the flow of parallel filters is evenly distributed to control the degree of contamination of the filter elements to the same degree. Controlling the inlet pressure is to ensure the outlet flow. As the degree of contamination of the filter element increases, the inlet pressure must be increased to ensure filter flow. When the pressure reaches the maximum pressure difference that the filter element can withstand, it cannot be raised any more. At this time it is time to clean or replace the filter element.