Is there an error in the pressure setting value in the PID?
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In Figure 1, the head of the pump is 293.3 ft, which corresponds to a pressure of 127 psi. However, the PIT alarm on the discharge line is set at 100 psi for high levels, and at 111 psi for extremely high levels. A PV valve is also used for control (see Figure 2). In Figure 2, there is a PV pressure control valve in the pump’s discharge line that leads back to the water tank; the pressure setting for this valve is 87 psi, at which point the valve is in a semi-open state. Question 1: Does this 87psi setting keep the valve in a semi-open, semi-closed state forever? Should the PV be closed while starting the pump, and then adjusted to 87 psi once the pump starts properly? If it remains in a semi-open state at 87 psi, then when the pump is started remotely (with the outlet manual valve open and the PV only partially closed), the pump’s pressure will always be at 50 psi, meaning it doesn’t operate in its efficient range and generates noise. Question two? Isn’t this setting of 87 psi incorrect? So how should it be changed?
That PV valve is marked as AC; it’s a gas-shut off valve
First, check whether the pump outlet flow is normal and what the status of the pressure control valve is when the pump outlet pressure is 50 psi. Logically: The pressure at the pump outlet is much lower than the set value, so the pressure-controlled valve should be in its fully closed position. If the status of the pressure-controlled valve is correct and the flow path is proper, then possible reasons are: 1. There is excessive flow from the pump outlet to the downstream circuit, which can be controlled using the valves in that circuit. The 2-stage pump is in a semi-evacuated state, resulting in low outlet flow. If the equipment is operating normally despite the pump not having emptied it, first switch the pressure control valve to manual mode and close it to a smaller opening, then adjust it using the pressure from the pump outlet to the backflow valve.
This post was last edited by chengbin on 2017-11-19 at 12:59. I get it; the pump chosen is probably too large. This PV is located in the pipeline returning to the tank, and it is used to regulate the pressure at the pump outlet. It’s so embarrassing :( This 87psi value is probably meant for the outlet pipeline, to maintain the pressure in it. rather than the air pressure of this pressure valve. Because the pump model is too large, it cannot operate in the efficient range.
The diameters of the inlet and outlet pipes as well as the return pipe for this pump are the same, which is an unreasonable design. A return pipe of such large diameter should be made as small as possible; it is only necessary to ensure the minimum flow rate required by the pump – otherwise it represents a waste. If the medium in the tank needs to stay stationary, it is even more important to keep the return flow rate as low as possible.
I’ve learned it; I hadn’t considered it from this perspective before. I want to shift the blame – this was designed by AKTINS for some rich guy; cost considerations weren’t taken into account at all; P