Vacuum gauge before the centrifugal pump
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A vacuum gauge is installed in front of the centrifugal pump. Under normal operating conditions, should the reading on this vacuum gauge be 0 (when water is drawn in from below) or above 0 (when water backs up)? What changes occurs in the reading of this vacuum gauge when the valve downstream of the pump is opened wider or narrower? If there is air leakage before the pump or the filter in front of the pump is clogged, will it show negative pressure and will the reading increase?
Vacuum gauge at the inlet of the centrifugal pump: there is little change whether the outlet valve is opened wide or narrow. If the inlet filter becomes clogged, negative pressure will occur, and this can lead to cavitation in the impeller over time.
Vacuum gauge at the inlet of the centrifugal pump: there is little change whether the outlet valve is opened wide or narrow. If the inlet filter becomes clogged, negative pressure will occur, and this can lead to cavitation in the impeller over time.
Vacuum gauge at the inlet of the centrifugal pump: there is little change whether the outlet valve is opened wide or narrow. If the inlet filter becomes clogged, negative pressure will occur, and this can lead to cavitation in the impeller over time.
Vacuum gauge at the inlet of the centrifugal pump: there is little change whether the outlet valve is opened wide or narrow. If the inlet filter becomes clogged, negative pressure will occur, and this can lead to cavitation in the impeller over time.
Under normal pump operation, does this vacuum gauge read 0 (when water is drawn in from below) or above 0 (when water backs up)?
Is it necessary to install a vacuum gauge? Generally, a pressure gauge is installed at the outlet.
Normally, it is not installed, as the inlet often gets blocked; installing a gauge makes it easier to determine the situation.
A drop in the pump’s outlet pressure indicates that the inlet is blocked; there’s no need to install a vacuum gauge at the inlet. In fact, installing such a gauge can lead to air leaks, which is not good for the pump.
When the valve behind the pump is opened wider, the pump’s flow rate increases, the vacuum level at the inlet rises, and the reading on the vacuum gauge certainly goes up as well； The same principle applies when the valve is opened slightly. The vacuum level decreases due to air leakage before the pump, and the reading drops as well. For oil pumps in the petrochemical industry, some standards require pressure gauges to be installed at both the inlet and outlet; the situation regarding water pumps is not quite clear.