The Backpressure Relief Valve is used to regulate upstream pressure in SWAS for analytical
measurement sensors, maintain a constant inlet pressure before the analyzers which help stabilize
the flow rate for each analyzer.
When some analyzers are installed parallel for a same sample source, the backpressure relief valve
can provide constant inlet pressure which allows all analyzers to be able to be shut off at all times
without varying the pressure and flow of the rest.
CAUTION: The necessary protective equipment must be used in order to avoid knocks, cuts and
entrapments during installation. Follow this procedure for correct installation:
The BPR must be installed in according to process diagram below in parallel with the analyzers and
with its outlet directly to atmosphere.
When sampling system works at high pressure and high temperature, almost components illustrated
in process scheme will be needed. If not installed these components, BPR could fail, resulting in injury
to persons or damage to other equipment.
As illustrated in the scheme below, the BPR only has to control pressure at 1.5 barg (22 psig) relieving
a part of sample flow. Both connections on the BPR are ¼" NPTF and wetted materials are AISI 316
stainless steel and Viton®.
The BPR must be fixed to the panel using a M‐6 screw located in the upper part of the cover.
Before start the installation of BPR, be sure that there is no high pressure or high temperature
fluid inside the tubing to connect the BPR:
It is advisable the use of corrosion resistant pipework suitable for the fluid being sampled in order
to connect BPR to sampling stream.
Keep the length of all tubing and pipes to a minimum, specially outlet tubing if installed.
PRODUCTDESCRIPTION DIMENSIONALANDCONNECTIONDRAWING
INSTALLATION
In normal operation, this valve must be open and sample must flow through it. When sample
pressure is increased, the valve must open wider in order to maintain pressure at its adjust point
and flow through the valve is increased. When sample pressure is reduced upstream, then the
valve reduces the flow path orifice in order to maintain pressure and the flow is reduced. If
pressure in stream is reduced below valve adjusting point, then no flow is observed at valve
outlet connection and valve is not working.
OPERATIONBASIS
Maintenance of the BPR only consists on frequently cleaning and/or replacement of the
diaphragm when pressure regulation is not accurate. Follow the instructions below to disassemble
and reassemble the BPR in order to do maintenance:
MAINTENANCE
1. First of all, it is advisable to use a bench in order to fix the BPR and avoid unexpected
movements or turns that can difficult the operation.
2. Remove alternatively three of the six screws around the spring housing flange which hold
the spring housing to the body. In order to remove the screws it will be necessary to use an
Allen key size 3.
3. Replace the three screws with three longer screws, tightening them until the screw heads
bottom out on the body flange.
4. Remove the three remaining screws.
5. After loosen the long screws until compression is relieved from spring and is possible to see
and remove if required, specially in case of diaphragm replacement.
6. In order to assemble the valve again, it will be necessary to tight the three long screws and
then tight the other three screws.
7. Last, remove three long screws and tight three screws instead of them.
DISASSEMBLYANDREASSEMBLYOFBPR
