Pulsafeeder Pulsar Shadow - Manual (Page 39)

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11. Appendix I PULSAlarm Leak Detection System
11.1 PULSAlarm Leak Detection Reagent Head Assembly
The PULSAlarm leak detection
reagent head assembly consists of
reagent head, leak detection
diaphragm, suction and discharge
check valves, vacuum bleed port,
and optional pressure/vacuum
switch and gauge. The reagent
head, diaphragm, suction and
discharge check valves are the only
parts of the pump to contact the
process liquid; consequently,
maintenance is critical to pump
performance
Figure 24
A sealed system must be maintained at all times during pump operation, whether leak detection
is required or not. If the proper level of vacuum, between 10 in and 26 in. (250mm to 650mm)
Hg, or a sealed pressure system is not present, decreased flow and/or diaphragm damage will
occur. Please note that the factory setpoint for actuation of the vacuum switch is 6 in (152mm)
Hg (vacuum) or 5 psig (pressure).
11.2 PULSAlarm Leak Detection Diaphragm
Double, or sandwiched, TFE diaphragms are sealed at their peripheries to an intermediate metal
spacer ring. The space between the diaphragms is sealed so that the diaphragm functions as does a
standard single diaphragm. For the vacuum system, the space between the diaphragms is evacuated
of air to produce a vacuum. For the pressure system, the space between the diaphragms is filled with
a small amount of fluid. At startup, any excess fluid in the system is expelled through the check
valve, and then the system is capped and sealed. The fluid as supplied from the factory is a silicone-
based oil, but an alternate fluid can be used if compatibility with the materials of construction is
verified. This space is connected to an adjustable electrical switch (optional) that actuates in response
to loss of vacuum or buildup of pressure resulting from rupture of either or both diaphragms. Switch
operation can be used to perform any external function, typically to signal an alarm or turn off the
pump. For component location refer to Figure26.
PULSAlarm leak detection can utilize a vacuum or pressure detection system. Although both
systems are similar, they do utilize different parts and require specific set-up procedures. Always
ensure that you are following the procedure correct for your system.