Note 1: See Table 1 for Inlet Separator Capacities
Note 2: See Table 2 f or Discharge Separator Capacities

Silencer Sizing/Selection
Common Vacuum Pump Operational and/or Corrosion Problems to consider: 
•    High backpressure
•    Loss of liquid seal
•    Improper seal leg length
•    High conductivity liquids
•    PH (7 = Neutral)
•    Solid fouling
•    High velocity flow erosion
•    Cavitation 

More about Vacuum Pump Separator/Silencers
Inlet Vacuum Pump Separator/Silencers protect the pump from liquid slugs or excessive system liquid loads. Discharge Vacuum Pump Separator/Silencers provide noise reduction and protection from seal fluid discharge to atmosphere. 

Vacuum pump systems have two phases of operation that must be evaluated when sizing and selecting the proper separator/silencer: 
1) Start-up: Where the vacuum pump has begun to evacuate the system starting at atmospheric pressure. Power requirements and system pressure drop are at the maximum level during this phase. As the system is evacuated, the inlet pressure decreases and the system pressure drop and power requirements decrease. The total inlet flow (ACFM) remains essentially constant but because of decreasing inlet pressure, the discharge volume decreases until normal operating conditions are reached. 

2) Normal operation: Typically, peak noise levels occur during normal operation. 
Vacuum systems using liquid ring vacuum pumps are typically closed-loop on the suction side of the pump and discharge to atmosphere on the outlet side of the pump. 
The size of the separator/silencer is dependent on the inlet gas flow in ACFM, and the seal fluid liquid load in GPM. Due to the vacuum condition, a secondary pump (barometric leg) may be required to drain the separator sump. If a barometric leg is utilized, the vertical length should be 13.6 inches for each inch of mercury (Hg) vacuum, the barometric leg should also have a liquid seal loop at the bottom. 

Model PDF Type Separation (of 100 microns or larger) Silencing
171 2.7 Discharge High Efficiency--99% Low Performance
173 3.0 Discharge High Efficiency--99% Low Performance
175 5.3 Discharge High Efficiency--99% High Performance
181 2.2 Inlet Efficient—90% Low Performance
185 2.7 Inlet High Efficiency--99% Low Performance

VANEC Inlet Separators are designed for use on the inlet of liquid sealed vacuum pumps.  They separate the process liquid from the gas stream. Available models: 181, 185

VANEC Discharge Separator/Silencers are designed for use on liquid sealed vacuum pumps.  They separate the seal water from the gas stream while suppressing the vacuum pump exhaust noise.  Available models: 171, 173, 175

All VANEC intake separator/silencers are designed for full vacuum (29.92” Hg) at 150°F.

VANEC Separator/Silencers are available in: 

Carbon steel 
300 series stainless steels 
FRP – fiberglass reinforced plastics 
Other materials upon request

Recommended Operating Velocity Limits  
4000 to 6000 FPM 

Pressure Drop Factors (PDF)  

Vacuum Pump Separator/Silencers​