Ejectors should be located where they can be readily taken apart for inspection and replacement of parts.

Ejectors are usually vertically installed to discharge downward and provide the best possible drainage. They will, however, operate in any position if exhaust and vacuum lines are properly configured.

Most ejectors will not work if steam pressure falls below the minimum operating value. The steam supply must be able to maintain steam pressure at least as high as the minimum value (+10%, -0%) of the ejector as measured at the ejector’s nozzle head/steam chest. See nameplate for minimum operating value.

The amount of steam passed through the ejector nozzle is directly proportional to the absolute steam pressure. High steam pressure causes excessive steam usage. It rarely helps performance and frequently hurts it.

If steam pressure varies over a wide range, a pressure regulator valve should be installed in the steam line and set at minimum operating pressure or slightly above.

The steam supply should have no more than 2-3% moisture. If steam quality is poorer than this, the ejector must be operated at a higher steam pressure. Proper performance cannot be obtained if the steam is too wet.

Steam goes through the ejector at velocities higher than the velocity of sound. Drops of moisture in the steam at these velocities will cut grooves in the nozzle and diffuser, requiring more frequent replacement.

Placing a steam separator in the steam line near the ejector is the best way to overcome wet steam. If the separator is too far away from the ejector, however, condensate will form in the steam line connecting them. The separator should also be properly sized for the amount of steam passing through it.

Superheated steam does not usually help and can hurt ejector performance; but it does guarantee dry steam. Less than 50°F of superheat does not have a negative impact on ejector performance.

The steam supply line should be the same size as the ejector’s steam connection. There will be too much pressure loss if the line is too small and too much heat radiation and wet steam if the line is too large.

A shut-off valve should be located in the operating area. Another shut-off valve, accessible to anyone doing service work, should be located at the ejector. There should also be a union in the steam line between this valve and the ejector steam chest (nozzle head) to permit easy removal of the steam chest.

Steam lines fill up with condensate when not in use. Excessive moisture can erode the ejector and get into the vacuum system. It may also take additional time for the ejector to warm up and give satisfactory performance.

Condensate is blown out through the ejector and into the exhaust piping on start-up in some installations. An auxiliary blow-down valve can also be used to rid the lines of moisture before turning on the ejector.

All JET-VAC ejectors with small nozzles have internal steam strainers. Unscrewing the inspection plug provides access to the nozzle and strainer. An additional steam strainer in the line is optional.

New steam lines contain dirt and scale and should be blown out before connecting to an ejector. Most clogged steam nozzles occur in the first few weeks of operation.

All steam lines, steam separator, steam chest (nozzle head) and other high-pressure steam parts require insulation by others. Other parts of the ejector need not be insulated.