Liquid Transient and Control System


Thread Starter

Marco Rivas

Dear List;
I am faced with a project concerning algorithm development for control valves and its impact in liquid transient creation (waterhammer).

Do you know of practical guidelines? How could I put it as a constraint in an algorithm independently of the controller technology?

Best regards

Igor Caganek Automated Sonix Corporation


Your task is not going to be simple or easy. Water hammer is a complex phenomena, there is no simple algorithm that you could plug in.
You may have to get books on Hydraulics or Fluid Dynamics and study the subject. Not even all of them will cover your subject. Check technical book publishers like McGraw-Hill. Check your college library and Dept. of Mechanical Engineering.

Generally, water hammer is most severe in long pipes with high velocity and fast closing valves (check valves). In extreme cases, water hammer could burst pipes. Good luck with your studies.

Igor Caganek
Automated Sonix Corp.
Check with Marrotta Valve Corp in Boonton, NJ(?). They had a nomagraph. Unfortunately, I don't have any other information regarding their existence.

Phil Corso, PE
Trip-A-Larm Corp



Check the following book:
"Water Hammer - problems and solutions" by B.B. Sharp

Best wishes

If your valve is open/close type (no control), try to slow down these two actions. Valve supplier will guide you in the appropriate modification of the pneumatic signal.
The location of the valve is of prime importance, particularly the maximum pressure drop she can stand. I have seen valve complety vaporised by excess of cavitation. I'm saying that because
hammering results of excessive pressure.
If the valve is included in a closed loop, for sure there is a mistake in the tuning.
.......Continued .......20/07/2000
Instead of sending an ON/OFF signal to the valve,
then send a ramped analog signal uP/Down.
There were plenty of analog modules doing that.
In 1983 I was largely involved in DCS systems
these blocks were available.
If none of these avenues are near hand,
then put a restriction on the pneumatic signal.
For instance a Swagelok needle valve,one on each signal way.
The most complete book on hydraulics (well illustrated) that comes to my mind, was a translation from Russian. I am not sure about the spelling of the author but it was 'Iceldick'?
Published by EYROLLES (France).