Greeting from Ireland!

I have a problem with hammer in a sanitary system.  Altering the rate of opening /closure on valves has delivered some degree of success, however I'd like to know if anyone has had success with other methods?  Some sort of pulsation dampener would suit but I don't think they would be permitted - GMP, PWEC system, Sanitization etc!

I'd appreciate views/advice?

How a bout a soft seated check valve or an in-line orifice.

What are the other dynamics of the system? For example the line velocities, how are the return flows controlled, etc, etc.

HEC

One way to prevent water hammer is to install a return loop.  And tap off of the loop at each user.  This will provide a contineous flow to keep the system flushed with sanatary material and allow flow to each user.

It looks like this thread is a bit old but Arsef's post is pretty recent.

Arsef's response is the preferred solution.  In general, sanitary systems, Ambient WFI, Hot WFI, RO, etc have a looped distribution system.  This is to prevent system contamination and biofilm formation.  All dead-legs should be avoided and zero-static valves are preferred at each distribution point.  Line velocity is considered in the design to prevent biofilm.  Also, remember to have a spray ball on the return to the storage tank.  It is important to keep the entire surface of the tank sheeted with water.

Because this is a dynamic system, there should not be water hammer.  If you have hammer in a looped system, check your back pressure control valve.  Of course, if the system is in place this is not an easy solution to pursue.

Check valves are not recommened in sanitary systems.  I do not see how that will help with hammer.  If back flow is a concern, an air-break is the proper way to go.  Of course this too must be a closed system to maintain sterility/sanitary conditions.  Vent filters on tanks, etc.

I would agree that the best approach is to look for the source of the hammer.  A VFD on the pump(s) could be used to ramp up and ramp down may help.  Slow (slower) closing valve actuators might help.  Any chance that vaporization is occurring (and collapsing) in some part of the line?

The only pulsation dampener that I have seen that was intended for a sanitary system was made by APV Gaulin for use with homogenizers.  I never actually used it and do not know anything about it.     All others, including the air release valve, would not be appropriate for “sanitary” systems.