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25/08/20 R6
a. The BPR is not certified as or marketed as a pressure vessel
safety relief valve. The BPR is a precision control valve. Guarding
against overpressure must be achieved with devices designed and
marketed as such.
b. Sensitive diaphragms and external seals can leak. It is the
responsibility of the end user to use this product in a way that
prevents injury to personnel should leakage occur. See Standard
Terms and Conditions for important Limitation of Liability notes.
c. If the internal diaphragm ruptures or leaks, the gas or fluid on the
pilot port can be introduced into the process fluid. Make sure that
the fluids are compatible and not hazardous when mixed.
d. If the internal diaphragm ruptures or leaks, process fluid can enter
the pilot port plumbing.
i. Make sure that the process fluids and the pilot are compatible
and not hazardous when mixed. Most auxiliary pressure regulators
used to provide pilot pressure to the BPR are of the self-relieving
design. Guard against the process fluid relieving out the pilot
regulator if the BPR diaphragm fails. One method to accomplish
this is to set the pilot pressure into a static volume chamber that
is sealed with an ON/OFF valve after the pressure is set to the
desired value. Another method is to feed the pilot pressure from
the pilot regulator through a check valve to the BPR. In order to
reduce the pilot pressure a bleed from the pilot port to a safe
location must be employed. In many cases this bleed can be made
to the output of the BPR.
ii. If an electronic pressure regulator is used then special
consideration must be made. In addition to reviewing the
prospect of having the process media coming in contact with and
venting out of the electronic pressure regulator, the possibility of
ignition of the media by the electronic pressure regulator must be
examined. It is the users responsibility to determine if a hazardous
area classification exist and to make sure that the electronic
pressure regulator employed meets or exceeds the requirements
of intrinsic safety for that area.
e. If the internal diaphragm ruptures or leaks the result is often that
the BPR will fail into a closed position. This results in a blocked
pipe with no path for the fluid to escape through the BPR. Over
pressurization of the upstream can occur. Steps must be taken
to ensure that the upstream piping is made sufficiently strong to
withstand this or is guarded by an overpressure relief device.
f. Make sure the process pressure to be controlled is connected to
the BPR “I” Inlet port. Process fluid flow is from “I” Inlet to the “O”
Outlet. If the BPR is connected in reverse it will still operate but it
will give poor control and can result in excess pressures.
g. Observe the maximum temperature and pressure ratings on the
BPR label. Take steps to insure these values cannot be exceeded.
Where necessary to protect equipment, a suitable type of safety
overpressure relief valve must be connected in parallel to the
BPR. The overpressure relief valve must be rated to prevent the
pressure or temperature from exceeding the BPR maximums as
listed on the BPR label.
In some installations a rupture disc may be substituted for the
safety relief valve.
h. If the discharge piping on the BPR “O” Outlet port becomes
blocked, the BPR will open and fill the discharge piping to the same
pressure as the maximum pressure in the system. The discharge
piping must be rated to contain this pressure or have a safety relief
valve to limit this pressure at or below the safe pressure of the
discharge piping.
i. Do not use the BPR as a structural member. All piping and plumbing
connections to the BPR should be adequately supported. The
BPR series is available with a mounting bracket to facilitate the
installation.
j. Enriched oxygen media (>21%) should not be used in the BPR
unless Equilibar has specifically worked with you to provide a
product rated and labeled for enriched oxygen. Standard products
are not oxygen cleaned. Particle impact, adiabatic compression,
and diaphragm motion can all cause ignition in an enriched oxygen
media. This kindling chain can cause the entire BPR to oxidize
extremely rapidly resulting in high temperatures, discharge of
flames and molten metal, and unrestrained escape of process
fluid.
k. The metal cap and body of the BPR are excellent conductors of
heat.
i. Assume the external temperature of the BPR will rise or fall to
match the temperature of the process media flowing through it. In
addition to thermal hazards posed to humans by directly touching
the BPR exterior, it is the duty of the end user to verify that the
temperatures of the process media do not exceed the ignition
temperatures of any combustible gases or dust (or mixture) that
may be present local to the BPR.
ii. Assume the internal temperature of the BPR will rise or fall to
match the temperature of the ambient environment. Ensure that
the process media flowing through the BPR cannot be damaged
or ignited by the maximum and minimum ambient environment
temperatures. Low ambient temperatures can cause the media
within the regulator to freeze. Expansion cooling in certain gasses
can also cause freezing. Freezing can block the BPR and cause
excess pressures to build on the “I”, Inlet, port. Expansion of
water due to freezing can damage the regulator. Ice formation
from freezing can perforate metallic foil diaphragms.
m. The BPR has been carefully designed by skilled engineers to
provide proper safety ratios and adequate pressure regulation.
Do not attempt to modify the BPR in any way, including adding
or enlarging orifices or ports or replacing bolts (cap screws. Only
replace the internal O-rings or diaphragms with Equilibar factory
provided repair parts.
n. Never perform maintenance or inspections on a system when
pressurized fluids are present. De-pressurize the system before
performing this work. De-pressurize inlet pressure before
reference otherwise a quick drop in reference pressure can lead to
a violent exhaust of the upstream pressure through the regulator.
Research Series Back Pressure Regulator
SYSTEM HAZARD ANALYSIS
Both normal operation as well as possible failure modes and foreseeable misuse must be accounted for in the design of the system
which interacts with and connects to the Equilibar back pressure regulator (BPR). It is the responsibility of the end user to account
for these hazards.
Please read all of the following safety and hazard precautions before installing or operating any equipment.
PATENT
This regulator is subject to one or more of these patents: US6,886,591, US7,080,660, US7,673,650, US8,215,336, US9,447,890
DE60322443D1, GB1639282, FR1639282, EP2724060
www.equilibar.com/support/patents/
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