quote:

Originally posted by Alex J:
Dax,
The schematic you sent shows the silencer but location within the system but I'm curious if it is located directly on compressor discharge flange where it should be. What type of silencer is it? What's your email address?

quote:

Originally posted by Steve Schultheis:
Ok, I was wrong, looks like a small high speed refrigeration compressor.

The vib levels are associated with the HP rotor, but the levels don't seem that high to me. Are you experiencing failures?

quote:

Originally posted by Steve Schultheis:
Dave_G wrote back on the first page:

"If you are talking of gas pressure pulsation itself and not vibration caused by it, then why worry at all? Pressure pulsations are practically not present in the receiver tank."

Sorry Dave, but in my opinion this statement is not correct at all. Pressure pulsations are always a serious consideration and worth worrying about in any screw compressor applicaction, and perhaps I am misunderstanding your statement, but pressure pulsations are always present in the receiver at some level. Pressure pulsation not only causes vibration, but also impacts performance.

Dave_G wrote:

"Likely you are experiencing such a high vibration on the pipes. If so, run a simple bump test and install braces if at resonance."

Again my personal opinion is that this is inappropriate advice. This may work if there is one small bit of piping that is resonant, but typically the high frequency nature of screw compressor pulsation makes this approach impractical, resulting in bracking of every instrument line, small bore connection and branch. In addition it is not unusual to have pipe wall modes excited as well, and that would require changing pipe schedule to detune rather than a brace. In general it is much better to control the pulsation than to detune piping.

Sorry, but regardless of the level of detail available on the installation, I disagree with your replies.