• Steam Ejectors
  • Ejector Selection – Steam ejectors are a simple, low cost type of vacuum pump/compressor. Ejectors can be sized quickly by vendors if they know the Dry Air Equivalent of gases and vapors produced by the process under vacuum.
  • Condenser Selection – Water vapor in the exhaust from an ejector is sometimes condensed to reduce the vapor load that must be handled by downstream vacuum pumps. In direct contact condensers, cold water is sprayed directly into the ejector exhaust and all of the liquid drains out of the bottom of the condenser.  An indirect contact condenser can be used if the condensable portion of the ejector exhaust is toxic or valuable and cannot be discharged to a waste water treatment plant.
• Liquid Ring Pumps
  • System Load Calculation – Total load on a vacuum pump is usually made up of a mixture of non-condensable gases and water vapor. The non-condensables can come from air leaks into the system and carbon dioxide dissolved in water used in upstream direct contact condensers.
  • Dynamic System Simulation – During start-up of a system operating under vacuum, the system goes through a pump down phase where high capacity is desirable. If the vacuum pump motor is equipped with a variable frequency drive, the pump speed can be turned down later to match the steady state load and save energy.
  • Vacuum Pump Selection – Choosing the correct vacuum pump involves matching a pump to the system load, selecting direct or belt drive, and selecting the appropriate material of construction. Direct drive pumps are mechanically simpler, but the drive ratio of a belt drive pump can be altered easily by changing sheaves.  Cast iron is the most common material of construction; cast iron vacuum pumps up to 15 or 20 hp are often stocked by manufacturers.