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General Description
When installed in a system as
shown in Figure 1, the Sentry®
Back Pressure Regulator/Relief
Valve (BPRV) holds a constant
pressure of approximately 20
psig (1.4 barg) at the analyzer
inlet. This pressure is maintained
independent of source pressure
fluctuations or sample flow
changes. If inlet pressure rises,
the regulator opens to let excess
flow pass through to drain. This
flow is usually used as the grab
sample. This unit also acts as a
relief valve in the event of an
over-pressure condition.
Installation
The Sentry BPRV should be
installed in sequence according
to Figure 1. The BPRV only has
to control pressure between 20
psig (1.4 barg) and atmosphere.
This allows very precise pressure
control, minimizes plugging and ensures reliability. Connections on the BPRV are
¼" NPT Female and wetted materials are 316 SS and Viton®.
Operation
In the normal mode of operation, there should always be a flow from the exhaust
port. This flow will increase with rising source pressures and decrease with falling
source pressures, unless the Sentry VREL® valve is reset to maintain the total line
flow at the set point. The Sentry BPRV also functions as a fail safe relief valve. The
relieving capacity exceeds that of the most commonly used 1/4" relief valve. Since
the BPRV is always in service, a malfunction is immediately evident. A relief valve
can freeze with no outward indication until it fails to operate in an emergency.
Maintenance
Basic maintenance of the BPRV generally consists of cleaning and/or replacement
of the diaphragm. Follow the directions below to disassemble and reassemble the
BPRV for maintenance.
The BPRV is spring loaded. Do not remove the six screws that hold the housing to the
valve body without first reading these instructions completely.
Required Materials
#2 Phillips screwdriver
ƒ
#8-32 x 3" screws (qty 3)
ƒ
Safety glasses
ƒ
Torque wrench
ƒ
Disassembly & Reassembly
1. Remove three (3) of the six (6)
#8-32 x 1/2" screws which hold
the spring housing to the body.
The screws that are removed
should be 120 degrees apart
(figure 2).
2. Replace the three (3) 1/2"-long
screws with three (3) #8-32 x 3"
screws, tightening them until the
screw heads bottom out on the
body flange.
3. Remove the three (3) remaining
1/2"-long screws.
4. Alternately loosen the 3"-long
screws until compression is
relieved from spring.
5. Clean or replace parts as
required.
6. For re-assembly, reverse the
above procedure using the 3"-long
screws as jack screws to reapply compression to the spring.
7. Check the tightness of all six (6) screws with a torque wrench. Alternate from
one side to the other, until all six are tightened to 16 in-lb (1.8 Nm).
Figure 1.
Figure 2.
Figure 3.
Screw
Label
Screw
Retainer
Nut
IN
Needle Seat
Body
O-ring
Screw
Label
Housing
Diaphragm
Assembly
Spring
Needle Seat
Body
Spare Parts List
6-04084A – BPRV Diaphragm Replacement Kit
Customer Support
With proven sampling expertise since 1924, Sentry products and services
provide business operations the critical insights to optimize process control and
product quality. We deliver true representative sampling and analysis techniques
to customers around the globe, empowering them to accurately monitor and
measure processes for improved production effi ciency, output, and safety.
Standing behind our commitments, we are determined to tackle any application,
anywhere.
We know that running an effi cient operation isn't easy. It requires thorough,
careful analysis of controlled, real-time data achieved through reliable, accurate,
and repeatable process monitoring and measuring. By eff ectively conditioning,
sampling, and measuring gas, liquid, slurry, powder, solids, steam, or water within
their production environments, our customers obtain the critical insights they
need to control and optimize their processes.
Yet, controlling your processes also means reliable customer support throughout
the life cycle of your equipment.
Customer Service—General information, warranty claims, order management.
ƒ
Installation Service—For systems that require specialized expertise upon
ƒ
installation.
ƒ
Technical Support—Troubleshooting, training, and technical manuals.
ƒ
Field Service & Retrofi ts—When a problem needs immediate attention.
ƒ
Replacements Parts & Consumables—Order your replacement parts and
consumables.
Sentry ProShield Services—Select from four ProShield Guardian service plans
ƒ
providing diff erent levels of support to protect your large system investments
with regularly scheduled maintenance.
To learn more, go to www.sentry-equip.com/support.
Spring
Housing
Diaphragm
Assembly
Poppet
OUT
Spring
Screws
Spring
Poppet
Retainer Nut
O-ring
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