Pressure surges result from sudden pressure changes and cause critical plant conditions. They can burst pipelines or distort the structure of a plant. As soon as shut-off devices regulate the flow in the plant, pressure surges are unavoidable. Since piping and all associated plant components, such as valves, are limited in terms of permissible overpressure and underpressure, preventive measures must be taken to reduce pressure surges.

Special valves can provide a remedy here: Pressure relief valves SRV open when the set pressure is reached and exceeded in order to discharge the medium from the system, and close slowly in a controlled manner so as not to generate a pressure surge. Pressure relief valves SAV open when the pressure reaches and falls below the lower set pressure in anticipation of a subsequent high pressure rise (upper set pressure) to atmosphere. The pre-opened valve then senses the overpressure of the high pressure wave and closes slowly in a controlled manner so as not to generate a pressure surge.

Poster "Surge simulation"

The pump works normally.

The pumps stops, the flow keeps going forward because of the moment, the pressure in the pipeline just behind the pumps drops, causes the lower pressure relief pilot to open, and the surge anticipating opens, which is called „anticipating“.

The pump stops for a while, the moment energy runs out and the flow keeps still instantaneously, because of the friction and the resistance of the flow rate in the pipeline.

After the pump has stopped, the flow comes back, the surge happens, the pressure in the pipeline behind the pump rises, causes the high pressure relief pilot to open, the main valve keeps open.

The surge destroys the equipments and the pipeline.

The function of the surge anticipating valve is to release the surge to another way (atmosphere).