Water Hammer
PROBLEM:
- Traveling pressure waves reflect back and forth and can resonate in a piping system, resulting in high pressure shock waves, which can break through pipe, joints, and elbows.
SOLUTION:
BENEFITS:
- The CRV® can act as a passive one way dampener, which will dissipate the pressure wave energy into heat, along the piping system.
- No more shockwaves or water hammer in the piping system.
Water hammer is actually a travelling pressure wave. It is initiated by the rapid stoppage of an incompressible flowing liquid in a piping system. For example, the pounding heard in process piping usually occurs due to a rapid valve closure or when large steam bubbles are introduced into water and the water rapidly collapses the steam bubbles. These pressure waves reflect back-and-forth between the interior wall of a piping system, reinforcing themselves as succeeding waves encounter each other. These waves become so energetic that catastrophic structural damage can occur.
The CRV® s geometric features prove extremely useful in controlling water hammer. When fluid is flowing in the forward direction, the CRV® is passive and offers no pressure drop and keeps the flow laminar. But when the fluid travels backward, it will exhibit a high pressure drop and it will not remain attached to the CRV® s vanes, as shown in Figure a. This high drag footprint (as shown in Figure b) for a backward flowing fluid and travelling pressure wave, acts as a passive dampener controlling the water hammer.
Dramatic improvements were seen in a piping circuit with four elbows between the supply line and the shut-off valve where the wall static pressure, with and without CRV® s, was measured. The results indicate that with CRV® s in place upstream of each elbow, the amplitude of the peak pressure pulse was 49% of that without CRV® s.