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YARWAY BACK PRESSURE REGULATOR ¾" THRU 6"
INSTALLATION AND MAINTENANCE INSTRUCTIONS
Before installation these instructions must be fully read and understood
PRINCIPALS OF OPERATION
The Back Pressure Regulator (BPR) is used to
regulate the outlet pressure from modulating
high pressure let-down valves or pump bypass
valves when unregulated conditions would
cause flashing, cavitation, choked flow and
other undesirable two-phase flow effects.
Mounted between flanges, the regulator
is completely contained within the piping.
It consists of a spring-loaded plunger whose
motion opens a cylindrical flow passage in
the center of the regulator. Flow variations
cause the plunger to respond by increasing
or decreasing the open flow area. The spring
loading is set to maintain the liquid pressure in
the line at, or above, the level chosen to prevent
cavitation and two-phase flow in the let-down
valve and in the piping between the valve and
the regulator.
FEATURES
• Prevents undesirable two-phase flow in
piping runs and in modulating valves.
• Reduces cavitation and erosion in
high pressure let-down valve trim.
Reduces noise level due to those effects.
• Stainless steel construction of all
operating parts.
• Installed between flanges; no welding
or other procedures or preparation;
no external connections.
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SPECIFICATIONS
Line sizes:
¾", 1½", 2", 3", 4", 6"
Class:
To 1500
Installation:
Inserts into line between
flanges
Flange facings: Facings match the raised face
requirements of ANSI B16.5,
Class 300 through 1500
Pressure
differential:
Selected for the application
See nameplate for the
operating differential pressure
STORAGE
Inspect the regulator assembly as received
against the purchase specifications. The unit
was carefully prepared and supported for
shipment. Verify the satisfactory condition
of the unit and store it, if necessary, in the
shipping container in a dry enclosure.
UNPACKING
1. Remove from the shipping container.
If necessary, use a sling around the cylinder.
2. Observe and follow any caution and
instruction tags attached to the unit.
3. Protect the surfaces that serve as gasket
sealing from scratches, nicks or marks.
4. Inspect for and remove any external or
internal shipping restraints.
5. If, for any reason, the regulator has
been disassembled, contact Yarway and
then if so advised, follow the directions
under 'Maintenance' for disassembly and
assembly instructions.
© 2017 Emerson. All Rights Reserved.
Engineering doc. #965910 Rev. B
VCIOM-02556-EN 17/05
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Summary of Contents for Emerson Yarway
- Page 1 YARWAY BACK PRESSURE REGULATOR ¾” THRU 6” INSTALLATION AND MAINTENANCE INSTRUCTIONS Before installation these instructions must be fully read and understood SPECIFICATIONS Line sizes: ¾”, 1½”, 2”, 3”, 4”, 6” Class: To 1500 Installation: Inserts into line between flanges Flange facings: Facings match the raised face requirements of ANSI B16.5,...
- Page 2 YARWAY BACK PRESSURE REGULATOR ¾” THRU 6” INSTALLATION AND MAINTENANCE INSTRUCTIONS PARTS LIST FIGURE 1 Item Part Seat Plunger guide O-ring Plunger Spring retainer Spring Seal Retaining ring Washer Draw bolt * Same diameter as raised face to align and center regulator in line except ¾”...
- Page 3 YARWAY BACK PRESSURE REGULATOR ¾” THRU 6” INSTALLATION AND MAINTENANCE INSTRUCTIONS ¾” SIZE 1½” - 6” SIZE TABLE A PARTS LIST Bolt Bolt Min. thread Washer Washer Washer Item Part size thread length length O.D. I.D. thickness Body ¾”-1½” 10-24 3½”...
- Page 4 YARWAY BACK PRESSURE REGULATOR ¾” THRU 6” INSTALLATION AND MAINTENANCE INSTRUCTIONS TROUBLESHOOTING AND DIAGNOSIS Symptom Probable cause Corrective action Sudden pressure loss Object holding piston open Increase flow rate and flush object through Disassemble and remove object. See 'Disassembly / Service / Reassembly'...