Hydraulic Pipeline Forces During Valve Closing

Nuffin' to do wiv me guv, but I'd start with the mass and velocity of the slug of liquid moving in the pipe.
Del

The speed of the upstream travelling wave and the size of the pressure pulse is dependent on the elasticity of the pipe material. Very elastic pipe will tend to damp the pressure foreces and slow the wave. Thats why water hammer is more of a problem in "stiff" pipes such as copper or steel, than in a rubber or plastic hose.

Hi Guest

Firstly your system will not be running very efficiently at 30 fps. If possible, you need to reduce the velocity by half at least, by increasing your pipe size.

Secondly, water hammer can be reduced or removed completely by utilising a valve that has about a 0.6 second lag in shutting. This can be done with a standard 'digital' valve that has an oil damper on the spindle. The delay can be adjusted within certain limits with variable orifices, usually supplied with the valve in the form of grub screws with different sized holes through them!

There is little point in trying to calculate the likely effect unless you have access to a very expensive flow modelling package!

Water hammer can be very destructive. I once was involved in a project where the pipes survived but the 9" concrete wall that they were attached to was demolished!

The pipeline velocity is above the economic-rule-of-thumb limit by a factor of about 3.

This a general problem and is mostly found on water based hydraulic systems. there are two ways to solve the problem. 1. Closing the valve at a controlled rate and if that is not possible, 2. Istall an accumalator close to the valve with a nitrogen charge of plus minus 30% of your work pressure. this will absorb the shock-load and protect the pipes from cracking. Hope it helps

Chris