Dear masters, there are urgent issues related to the filters that need to be resolved! ! ! !
Thread Content
The lean liquid filter in our system is located at the outlet of the lean liquid pump. The flow path is such that the fluid exits the pump and enters the filter; after passing through the filter, it returns to the pump’s inlet. What I would like to ask is: if the inlet valve of the lean liquid filter is closed while the outlet valve remains open, will the liquid inside the filter be emptied? Since the outlet line of the filter leads back to the pump’s inlet, if the filter becomes empty, will it be necessary to remove air from it again when the filter is used next time? Or the filter container is evacuated of air; since there is no air present, this step is not necessary, and it can be put into use right away! ! ! ! ! !
There won’t be time for that; there’s a pump inlet to supply the lean liquid, and besides, how could air get in if vacuum is being created? That doesn’t make much sense
No, it will be fine as long as the inlet is opened to add the medium
It is necessary to have a liquid-deficient buffer tank or storage tank in front of the pump; this tank and the filter form a communicating vessel. If the liquid level in the tank is above the top of the filter, there will be no vacuum; otherwise, a partial vacuum will exist, allowing air to enter.
This still needs to be determined based on the actual layout of the equipment on site. If the tank at the pump inlet is much higher than the pump inlet itself, the pump inlet remains under positive pressure, and thus the filter will not be subjected to negative pressure； When the pump is in operation, the inlet is under negative pressure. Since the filter itself is filled with liquid, as long as the seals are secure everywhere, it will not be emptied, and there is no need to refill the pump before its next use.
There are two sets of filters at the pump outlet, connected in series. If one of these sets needs to be flushed, it is necessary to close the inlet; the local inlet and outlet valves of that set must be closed, while the inlet and outlet valves of the other set remain open (the main inlet control valve is already closed). Moreover, since the outlet of the filter that has not been cleaned is still connected to the pump pipeline, the pump will continue to operate. Will the liquid inside that filter get emptied? If there is time, is it necessary to bleed air from the filter again?
Under normal operation, is the pump inlet at positive pressure or negative pressure? If the filter is removed, it is equivalent to having normal pressure; if there is negative pressure at the pump inlet, it is possible to draw the liquid out of the filter. After the filter is removed, some air gets in; if it is then connected to the system, gas may enter the pump inlet, causing air locking in the pump. It is recommended that after cleaning the filter, find a way to fill it completely before connecting it to the system.
The pressure gauge shows normal pressure, that is, zero kilopascals