The preferred slug volume ratio is 10 : 1 (Silencer Volume : Slug volume).
The silencer should be installed as close as possible to the compressor inlet
(direct mount if possible).

If the pulse frequency (fundamental frequency or harmonies) couples with the piping natural mechanical, a frequency resonant response (vibration) may develop. The intake silencer will act as an atmospheric pulsation control vessel and lessen this effect.

More About Reciprocating Compressor Noise
Intake noise is predominantly low frequency. The frequency and amplitude is a function of size and speed of the compressor. Large bore, low speed reciprocating compressors will generate air-borne pulsation waves if unsilenced. This airborne pulsation may be perceivable at a considerable distance from the source. VANEC’s model 121 can solve these problems.

The intake silencer size is determined by both intake slug – volume (swept volume of one cylinder), and flow velocity and allowable pressure drop.

Model 121 (SV) Slug Volume
1" 33 in3
1.5" 70 in3
2" 150 in3
2.5" 245 in3
3" 340 in3
4" 750 in3
5" 1150 in3
6" 1750 in3
8" 3950 in3
10" 7600 in3
12" 11500 in3
14" 16000 in3
16" 23500 in3

Silencer Sizing/Selection

The silencer size is determined by first calculating the slug volume and then evaluating the velocity and pressure drop. The larger of the two is the preferred selection.

Pressure Drop Factors (PDF)

Model Pressure Drop Factors
121 4.4
Single Acting 2000 to 3000 FPM
Double Acting 4000 to 5000 FPM

VANEC Intake Silencers are designed for use in suppressing the low frequency intake noise from reciprocating compressors.  Available models: 121

Recommended Operating Velocity Limits 
Intake Silencers

Reciprocating Compressor Silencers​