If a conventional centrifugal pump becomes evacuated, how should the operator handle it?

As an external operator: First, contact the internal operator to check the pump’s operating status； Second, contact the fitter (or maintenance personnel for moving equipment) promptly to go to the site and assess the situation ； Third, if time really isn’t available, internal adjustments are ineffective and there are no leaks in the pipelines on site, then the pump should be replaced by switching it out; the pump that is currently in use should be isolated from the system so that a mechanic can clean the filter screens ； Fourth, if there is a leak in the pipeline at the pump inlet site, it is necessary to contact the shift supervisor and the personnel responsible for maintaining the static equipment promptly to handle the issue. If the situation is severe enough to be unmanageable, follow the supervisor’s instructions and prepare to shut down the operation.

Repeatedly opening and closing the pump outlet valve didn’t work, so the pump had to be shut down

1. Determine whether there is a liquid level in the tower or tank; the instruments may be malfunctioning! 2. Is the temperature of the material in the cold pump too high? 3. Close the outlet valve; if it is possible to open the outlet drain, the gas can be released, allowing the level to rise naturally. 4. Cut the pump. 5. Have a blacksmith fix it and check if the inlet filter is clogged.

Your first reaction is to rush to the scene to deal with the problem. Temporarily reduce the pressure at the pump outlet to allow all the gas inside the pump to be expelled; if this does not work after two or three attempts, switch to another pump as soon as possible. This can lead to water being carried in along with the fluid, blockages at the inlet, an empty liquid level, and vaporization due to high medium temperature... If the liquid level is empty, it’s either because the operators inside failed to monitor the gauges properly or because the instruments are giving incorrect readings; it could also be caused by careless inspections by the operators outside. It’s really a problem to have to explain it in such a way.

Ordinary centrifugal pumps are equipped with self-sealing mechanical seals; vacuuming can damage these seals. Shutting down the pump is the safest approach – after that, the inlet and outlet should be closed, pressure released, and a mechanic should be called to replace the seal. Some large, high-power feed pumps are equipped with separate seal systems; in such cases, it is possible to activate the minimum flow line when the degree of evacuation is not severe. If this does not work, then the pump needs to be replaced. Severe cavitation can damage the impeller; I have seen accidents where cavitation caused damage to the impeller in pumps.

1. Switch to the backup pump. 2. Contact maintenance personnel. 3. If it is a heavy oil pump, check whether the sealing oil contains water

First, determine the cause of the vacuum; if air leakage is the issue, eliminate the air source, such as fixing a poorly sealed steam valve that allows water to enter. If the medium temperature is too high, vaporization and exhaust steam help to cool it down; if the liquid level is too low, transfer of liquid to another container or raising of the liquid level is necessary. Handle the blockage at the inlet by reversing the pump.

First, it is necessary to know the reasons that cause cavitation in centrifugal pumps. When cavitation occurs, those responsible for operational tasks must immediately go to the site, reduce the flow rate by closing the outlet valve in order to mitigate the effect of cavitation, and quickly determine the cause of it. Appropriate actions should then be taken based on that cause (which is what the experienced workers mean (by handling the situation according to its specific circumstances)). If the liquid level in the container is too low, the outlet valve should be closed immediately to control the flow rate; once the liquid level is stabilized, the flow rate can be adjusted ； When transporting light oil, too low a flow rate can cause vaporization and vacuum formation inside the pump. It is necessary to make repeated adjustments to remove the gas from the pump and increase the flow rate, or switch to another pump; after cooling and venting the gas, the pump can then be started again ； If steam enters the shaft seal and vaporizes, reduce the cooling water flow appropriately, open and close the pump outlet valve repeatedly to expel the gas; in severe cases, switch the pump and contact the maintenance team ； Wait.

When evacuating a conventional centrifugal pump, it is generally necessary to first reduce or even close the pump outlet, wait until an appropriate pressure is reached, and then slowly open it； The gas inside the pump can also be expelled through the vent valve at the pump outlet. It is necessary to check whether the seal oil pressure is appropriate, and then switch to the backup pump; the person responsible for pump maintenance should handle this

First, we need to see what kind of pump it is; the pumps used for rotating tanks in our company often run out of pressure. As long as it’s not a very long period of time, there’s usually no problem; the pump’s design should allow it to empty itself within a certain amount of time. Just use the tank pump again. We usually just need to turn the pump on and off repeatedly. Sometimes opening the outlet can also allow exhaust to escape, right? It will be troublesome if the high-speed pump gets emptied. The pump is usually switched only then.