The issue of inlet pressure in shielded pumps
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Our factory’s production is currently stable. Shielded pumps are used for transporting crude benzene; the nameplate indicates a head of 22 M, a flow rate of 60 M3/H, and a medium density of 0.889. 1. Is it normal for the pressure to be around 0.22 MPa? 2. At a pressure of 0.22 MPa, the pump outlet valve was only open by three threads, yet the flow rate reached 78 M3/H. Is this normal? 3. When laboratory staff take samples for testing, do our company’s employees use the outlet of the pump’s exhaust valve for such sampling purposes? Is this practice correct? I would be greatly grateful if someone could guide me.
As I understand it, points 1 and 2 are normal; the issue with point 3 lies in sampling – there’s nothing wrong with the sampling location; the selected area is the fresh material zone, not a dead corner
There are requirements regarding the flow rate for transporting benzene; I don’t understand the second point.
There’s no problem, as the 22m head indicated on the nameplate is only the head at the optimal operating point; the head curve of the pump is generally higher than that at the operating point. The actual head is the intersection point of the pipeline network curve and the pump curve
This post was last edited by cnoocjeff on 2009-11-8 at 21:23. 1. There should be no problem. 2. Contact the electrical team to check the current; generally, there’s no need for issues with the outlet valve. We need to use an outlet control valve for monitoring purposes. 3. The sampling point should be drained for a short period of time first, as there is still some dead zone present. Additionally, considerations regarding the medium’s temperature and toxicity must be taken into account when sampling
First, the outlet pressure of the pump is related to the inlet pressure; outlet pressure = inlet pressure + ρgh. Second, the flow rate at the pump’s outlet is 78 M3/H, which is too high. It is recommended to reduce the outlet valve to maintain a flow rate of around 60 M3/H
This post was last edited by Jizangwang Benyuan Jing on 2009-11-10 at 21:49. Does a lift height of 22m correspond to an outlet pressure of 0.22 MPa for the pump? Regarding Article 3, since a sampling tube (valve) has already been installed on the pump outlet pipe in my section, would sampling from the vent hole cause air to enter the pump or reduce the efficiency of the exhaust valve? Thank you all for your advice!