When sizing any vacuum system, be it batch or continuous, there are Six (6) sizing criteria that must be examined in
determining the correct selection of a vacuum system. They are:1) The Operating Pressure: The vacuum level desired in terms of inches Hg, Torr, mm HG, PSIA,. This will determine and/or
narrowly limit the choice of pump types we will be able to consider.
2) Pump Down Required: The time required to go from the initial pressure to our desired vacuum level.
3)
Volume of the System: The total volume of the system, vessel and piping, to be evacuated.
4) Gas Load: The composition of the gas to be handled by the vacuum pump. Is the gas a
condensable vapor, permanent gas, corrosive or inert. The gas/vapor composition will also greatly limit or determine the type of system we will consider.
5) Inlet Manifold Length: What is the
length, diameter, number of turns, and valves present or proposed that will reduce the capacity of the pumping system?
6) Economic Priorities: Items including utilization of
existing equipment, Initial First cost, Utility cost, Payback period, Duty cycle, maintenance and reliability.
