Consolidated 2478 Series Pressure Relief Valve Manual
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© 2020 Baker Hughes Company. All rights reserved.
During system operating conditions, the spring force
applied due to compression screw is higher than the
upward acting pressure force on the disc. As a result,
the valve is in the closed position. When system
pressure reaches the opening pressure of the valve,
the upward acting pressure force equals the downward
acting spring force, hence valve begins to open. If
system pressure increases more than the opening
pressure, the valve opens proportionately. There is no
pop type action on the liquid valve due to an absence
of expansion characteristics in liquid (incompressible
fluid). The valve lift will depend upon the degree of
overpressure. During the lifting action, the disc is guided
in precisely machine bonnet guiding surface. The valve
closes, once system pressure reaches closing pressure
of the valve.
X. Operating Principle
1. Remove Screwed Cap or Packed Cap-Lever assembly.
2. Remove Release Nut and Release Locknuts in valves with cap-lever
assembly.
3. Release Compression Screw Locknut and release spring compression by
turning Compression Screw counter-clockwise.
4. With valve Base held in vise loosen Bonnet to Base connection (use strap
wrench, do not use pipe wrench as this may crush the bonnet).
5. Holding Bonnet upside down, unscrew and remove Base.
6. With one hand on Disc, rotate valve over and remove Disc, Spindle, Spring
and Spring Washer Assembly from Bonnet.
7. Remove Disc by pulling the Spindle out of Disc pocket.
8. If Soft Seat is damaged as shown by nicks, cuts and dents, remove Retainer
Ring by a sharp tool. Subsequently, remove Soft Seat using the same tool.
These two parts must not be used again.
XI. Disassembly of 2478 Series Relief Valve
Do not disassemble
valve with pressure in
drum or header, as this
will result in severe
personal injury or death.
