15Instruction Manual
SECTION 5 - LEAK DETECTION (PRESSURE SENSING SYSTEM)
5.1 DESCRIPTION
(FIGURE 2, SHEET 1 & 2)
Milton Roy’s pumps are, by design, leakproof
and durable. In some applications, however,
added assurance is desired to protect the pump
from hostile chemicals, or protect the process
from contamination by hydraulic uids. For these
situations, Milton Roy has developed a highly
reliable diaphragm rupture detection system.
The diaphragm rupture detection system is an
optional feature, available on the Critical Service
line of metering pumps, which is used to detect
and signal if a hole or tear occurs in one or both
diaphragms. The system consists of two PTFE
diaphragms separated by four leak detection
rings (two A rings (8080) & two B rings (8081)).
Pressure in the four leak detection rings between
the diaphragms is monitored via a pressure
gauge. A machined port in the displacement
chamber at (5021) connects the diaphragms and
rings with tubing, gauge, and or pressure switch.
A low cracking pressure check valve (5000) and
a bleed valve (5100) are located between the
displacement chamber and the pressure gauge.
5.2 PRINCIPLE OF OPERATION
The system consists of two separate diaphragms,
four leak detection rings, leak detection ring
spacer (8082), and a pressure gauge (5030) or
switch (1250). During normal operation, the two
diaphragms are pushed tightly together and are
separated only around their outside edge by the
rings. Because there is no uid and very little air
between the two diaphragms, the system does not
experience pressure from the process when both
diaphragms are intact. The pressure is therefore
at atmospheric pressure, and the pressure gauge
displays 0 psi. The rupture detection system
senses process pressure only when one of the
diaphragms rupture. In the event of a rupture in
either diaphragm, uid rushes into the rings, and
the pressure at the ring rises rapidly to the pump’s
operating pressure. This pressure will be displayed
directly on the pressure gauge for visual indication.
An optional pressure switch is also available to
shut down the pump or provide an alarm signal.
The pressurized uid trapped between the pressure
gauge and the check valve can be relieved via the
bleed valve after the pump is shut down and system
pressure relieved.
5.3 SPECIFICATIONS
Maximum
Pressure Ratings:
Same as pump rating.
Materials:
Diaphragms: PTFE
Leak Detection Ring /
Tubing: Steel 304SS or
316SS
Flow Rate:
Derate ow by 5% on all
pumps
Accessories:
Pressure Gauge: 316SS
liquid lled (Standard)
Pressure Switch
W/Gauge : NEMA 4 or
Explosion Proof (optional)
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