Emerson 1808 Series Relief Valve or Backpressure Regulator User Manual

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Bulletin 71.4:1808
July 2010
D100163X012




W3716

W3507

Figure 1. Types 1808 and 1808A Pilot-Operated Relief Valves or Backpressure Regulators

The Type 1808 globe-style and the Type 1808A
angle-style, pilot-operated relief valves or backpressure
regulators are economical, compact devices used in
gas or liquid service to maintain pressure on oil and gas
separators, and in pressure relief applications in gas
distribution systems. The Types 1808 and 1808A are
available with either a Type 6358 or 6358B pilot. The
Type 6358 pilot is used in gas or liquid backpressure
applications throughout the oil and gas production
industry. This pilot offers a low bleed construction so
it only bleeds when it is repositioning the main valve.
Pressure relief applications in the oil and gas industry
are typically handled by the Type 6358B pilot. This pilot
has a bleed restriction to reduce the buildup pressure
required to reach wide-open ow. These units control
pressures from 3 to 125 psig (0,21 to 8,6 bar), and the
set pressure is varied to individual requirements by
the adjusting screw on the pilot. On gas service, the
pilot exhaust can be piped into the downstream piping
or vented to atmosphere. On liquid service, the pilot
exhaust should be piped into the downstream piping or
to a safe location.

—Units have fewer
parts for reliable service and minimum spare
parts inventory.
—Less than 12-inches
(305 mm) tall and weighs 25 pounds (11 kg) or
less, these units are easily transported and installed
where space is limited.

—Pressure connection in diaphragm
casings and factory-piped pilot tubing mean
no upstream control line is required on standard
installations. There are no mounting restrictions to
limit service.

Pilot exhaust port and standard tapped pilot spring
case (Figure 2) both come with removable vent for
remote piping when necessary. The standard
tapped pilot spring case comes complete with a
gasketed closing cap that permits pressure loading for
remote pneumatic adjustment of the set pressure.