A Leader in Silencing for Industry

Recommended Operating Velocity Limits:  4000 to 6000 FPM 

Pressure Drop Factors (PDF)  (See Technical Section)

Typically vacuum systems using liquid ring vacuum pumps are closed loop on the suction side of the pump, and discharge to atmosphere on the outlet side of the pump. VANEC inlet separator/silencers model 181 and 185 are efficient liquid separators and low performance silencers. VANEC discharge separator/silencers model 171 and 173 are high efficiency separators and low performance silencers. VANEC discharge separator/silencer model 175 is a high efficiency separator and high performance silencer. 

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 “barometric leg” or secondary pump 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. All VANEC intake separator/silencers are designed for full vacuum (29.92” Hg) at 150°F.

Pre-computed intake separator capacities at a velocity of 6000 FPM are available on Table 1. Nominal liquid separation efficiencies are: 

Model # 181  -  90% of 100 microns & larger 

Model # 185  -  99% of 100 microns & larger 

Pre-computed discharge separator capacities (model 175, 173, & 171) are available on table 2. Calculated capacities are based on a maximum discharge velocity of 6000 FPM. Nominal separation efficiencies are: 

Model # 175  -  99% of 100 microns & larger 

Free entrained liquid efficiencies are rated on the basis of average particle size and distribution. Atmospheric discharge of saturated vapor will produce a visible plume and some droplets, this is a normal thermodynamic effect. 

Vacuum System Operation & Separator/Silencer Capacity:

Vacuum pump systems have two phases of operation that must be evaluated when sizing and selecting the proper separator/silencer. 

The first phase is start-up, where the vacuum pump has begun to evacuate the system starting at normal atmospheric pressure. At this phase the power requirements and system pressure drop are at the maximum level. 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. Vacuum pump capabilities are typically expressed as inlet flow (ACFM) at a vacuum condition and temperature in inches of mercury (“Hg). Some carry over of seal fluid at the discharge separator can occur during start-up. 

The second phase is normal operation. Typically peak noise levels occur at normal operation. VANEC “Dynamic Insertion Loss” ratings are available on data sheets for each model. 

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

How to Specify & Order a Vacuum Pump Separator/Silencer:

VANEC will provide on request application and selection assistance. 

The following operating conditions and pump data are required: 

VANEC Separator/Silencers are available in: