Ideas for damping fluid borne noise?

[djk]

Looking at a refrigeration loop on a vehicle with a shut off valve. When the valve opens or closes, a clunk is heard by the passengers. Considering rubber damper for mounting, any ideas for in line fitting type suppression?

 

[RIVetron]

The first thing that comes to mind for me is to possibly implement an inline insulated enclosure with either a plastic or metal case, with a suitable insuation material inside the case to dampen noise emissions...<br>
<br>
the second thing that comes to mind was advice my dad gave me way back when I bought my first car - an old jalopy, he said "if it makes to much noise, just turn up the radio"<br>
<br>
best of luck,<br>
<br>
Paul

 

[VibrationSpecialist]

The fluid velocity should be less than 15 feet per second. You can try increase the size of the tube to reduce the speed. Q = A . V where Q = mass flow rate (constant), A = cross sectional area (inside the tube) and V is the fluid velocity. Once you decrease the velocity by increasing the area then the noise should be recudeced (less turbulent).

 

[djk]

Thank you Vibration Specialist. Unfortunately the tube length is about 12 feet and a larger tube diameter would be relatively costly. Since the initial posting numerous other solutions have been tried:<br>
- internal valve changes to reduce the speed of opening.<br>
- muffler upstream of valve in high pressure line. <br>
- resilient hose in circuit to absorb fluid energy. <br>
The best performing and most cost effective solution was a sharp edged orifice in the high pressure line just upstream of the shut off valve.