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CSA anti-surge tank AVAST

The innovative anti-surge tank A.V.A.S.T. has been designed to contain the devastating effects of water hammer, more precisely the transients coming from the sudden pump failure both for water and sewer systems. The device, fully automatic, proved to be an innovative and reliable solution thanks to the absence of air compressors, electricity, panels, bladders, pre-charges. A.V.A.S.T. is the ideal solution to avoid damages sometimes fatal for our systems as a consequence of uncontrolled overpressures and negative pressure waves.

Photo: CSA anti-surge tank AVAST

It is an object of this engineering evaluation is to determine whether any adverse hydraulic conditions or unacceptable surge will occur during the operation of hydraulic systems. The following video presents the simulation of the transient event generated in a pipeline whose profile is represented by the two red lines, with the pumps on the left side at the bottom and the downstream boundary condition on the right. The software shows the evolution of the HGL during the event and the pressure variations on critical point of the system, associated to the coloured vertical lines. In case of unexpected power failure at the pumps, without any surge protection devices nor air valves, it is evident the negative pressure followed by a pressure surge in the second phase of the transient.

Link video simulation pipeline without surge protection.

The picture below shows the minimum pressure envelope, depicted in purple and indicating severe negative pressure values, and the maximum pressure envelope in green reached in the course of the simulation.

Hydraulic profile without anti-surge protection.

Thanks to the use of CSA AVAST (pat. pending) the system is protected against unwanted and excessive pressure variations. The following video shows the same system with the introduction of CSA anti surge tank AVAST at the pumping stations, in addition to CSA non slam air valves along the profile, The purpose of AVAST is reduce the drop of the HGL in order to avoid negative pressure consequent to the pumps failure, to contain the pressure surge on the second phase of the transient by means of a patented air outflow control system.

Link simulation pipeline with CSA AVAST and SCA.

The picture below shows the minimum pressure envelope, depicted in purple, and the maximum pressure envelope in green reached in the course of the simulation. It is evident, compared to the same case without protection, the effectiveness of the solution chosen to prevent negative pressure and unwanted pressure spikes from occurring.

Hydraulic profile with CSA AVAST and SCA anti-surge devices.

CSA tech service is available for the evaluation of the water hammer phenomenon.