(2) Oil level gage. The oil level within the
2-3. Vacuum Pump.
vacuum pump is indicated in the window on the side of
(3) Vacuum pressure gage. The vacuum in
consists of a two-stage pump and a one-half horsepower
inches of mercury (HG) is indicated on the vacuum
electric motor mounted on a common base. The base is
pressure gage (located on the main control panel (fig. 1-
mounted on an elevated shelf on the left wall of the utility
transmission from drive motor to pump is by V-belt and
pulleys. The pump is connected through the van utility
system piping (fig. 1-7) to the laboratory compartment
outlets. The pulley-belt combination provides for a speed
(1) Check to see that all vacuum pressure line
of 525 revolutions per minute. The pump has a 58-liter
valve outlets in the laboratory compartment are closed.
per minute free air capacity, with a vacuum of 0.1 micron
(2) With the intake closed to minimize splashing,
(0.001 mm. Hg).
turn on the power.
(3) With the pump running, check the oil for
b. Controls and Instruments.
proper level. A gurgling noise, sometimes detected at
high pressures, should disappear after a few seconds. If
(1) Electrical Controls. Operation of the vacuum
it does not, check to see if the oil level is too low or if
there is a leak in the connecting lines.
pump is controlled by the vacuum circuit breaker on the