Multi-Stage Pumps

Multi-Ejector

Larger capacity vacuum pumps are created by placing identical nozzle sets in a parallel configuration either in the same body or in a stacked module. Additional vacuum flow capacity is attained but maximum level is not affected since that is determined by the nozzle series. This method provides a specific, repeatable increment of capacity increase that is very handy when sizing a pump for an application since the basic shape of the performance curve doesn't change. Vacuum flow and air consumption is increased in proportion to the number of nozzle sets and system evacuation time is decreased proportionately.

High Flow Mode

An air supply to the pump is turned on and high-pressure air flows through the first nozzle generating a vacuum flow as it passes into the second nozzle. As air is evacuated from the system, induced air flows into the vacuum port and is drawn into the first stage ejector (gap between the first and second nozzles) and combines with the compressed air flow from the first nozzle before passing into the second stage ejector (gap between the second and third nozzles). The powerful combined air flow induces a high vacuum flow rate through the second stage ejector until the increasing vacuum level causes the flap check valve to close. The valve closing point is dependant on nozzle series (A, E, M, ML, or X) and the operating air pressure. For example: at 87 psi the flap valve will close at 11" Hg for an ML series pump and at 18" Hg for an E series pump. This closing is evident by the change in slope of the performance curve.

High Vacuum Mode

After the flap valve closes, induced air continues to be drawn into the first stage ejector and the vacuum level will increase to the maximum level allowed by the nozzle series. At this point, the second stage is isolated and is not contributing to evacuation of the system. Some of our competitors offer three and four stage vacuum pumps but these provide very little benefit for industrial systems since a third stage will shut down at 3" Hg and a fourth stage will shut down at 1.5" Hg. EDCO nozzles are optimized to give extra vacuum flow at higher vacuum levels to more than make up for lower flows from 0" to 3" Hg. EDCO evacuation times to 12" Hg or higher will be equal to or better than our competitor.

Pump Series