Vacuum Sentry
TM
safety Valve
7
Installation
Electrical
The solenoid coil leads should be connected in parallels to the rotary vane
pump electrical source, preferably at the pump switch. Be sure that the
solenoid voltage and frequency are compatible with those of the pump
motor. In the case of three phase electrical power, the solenoid may be
connected to one leg and ground.
Ground the solenoid securely using the provided lug before
operation.
Mechanical
Vacuum Sentry
TM
is installed between the mechanical pump and vacuum
chamber or high vacuum pump. Refer to figure 1. Note that the flow arrows
on the unit’s label point from the vacuum system to the mechanical pump.
While it is preferable to mount it directly on the mechanical pump, it may be
located remotely. For best performance, the maximum volume should be on
the vacuum system side, and the minimum volume on the mechanical pump
side, of the Vacuum Sentry
TM
. Operation is position independent and
standard ISI-KF centering ring assemblies and clamps are used to connect
Vacuum Sentry
TM
. The valve body can operate in ambient temperatures up
to 100
o
C., but the solenoid is limited to about 50
o
C., because of the heat
generated by the coil. This should be kept in mind when selecting a
mounting location.
The body of the Vacuum Sentry
TM
is very rugged, and it is difficult to deform
it in any normal piping arrangement used in vacuum systems. It is possible
however that tremendous forces could result from thermal expansion, or
from a long run of pipe cantilevered from a fixed valve. Where this
possibility exists, it is necessary to provide stress relief for the valve by
installing a short bellows, and supporting the attached piping other than with
the valve.
Figure 1
Valves are shipped with plastic snap-on covers over the ports, in order to
protect the delicate seal surfaces and to keep the valve clean. These
covers should be left in place until the moment when the valve is to be
installed in the piping. A single fiber or bit of lint on an O-ring seal is
enough to prevent leak tight sealing. The usual cleaning techniques in
vacuum practice should be observed in installing the valve.
When installing the valve, adequate clearance should be allowed between adjacent
components so there is no sliding of seal surfaces against each other. Flanges that
have been assembled for some time may stick together. They should be separated
gently. Do not set the valve down on the seal surfaces unless they are protected.
