Complete downstream overpressure protection is
needed if the actual inlet pressure exceeds the outlet
Overpressuring any portion of a regulator or
associated equipment may cause leakage, part
damage, or personal injury due to bursting of
pressure-containing parts or explosion of accumulated
gas. Regulator operation within ratings does not
preclude the possibility of damage from external
sources or from debris in the pipeline. A regulator
should be inspected for damage periodically and after
any overpressure condition.
Figure 1. 1305 Series Regulator with Tapped Lower
Figure 2. Type 1305C Operational Schematic
1305 Series Regulators
The 1305 Series regulators (Figure 1) are direct-
operated, pressure-reducing regulators that resist
hydrate formation and regulator freeze-up. The
regulators are suitable for service with natural gas, air,
propane, and other gases compatible with the internal
parts. 1305 Series regulators are typically used on
high-pressure lines from wellheads and separators.
Regulator freeze-up resistance (see Figure 2)
occurs as the pipeline gas warms the nned inlet
adaptor and the orice area. As the gas cools within
the inlet adaptor due to pressure drop and volume
expansion, the warm inlet adaptor helps keep the gas
temperature above the freezing point of water and the
hydrate formation temperature.
—Brass inlet adaptor and spring case
plus stainless steel trim parts make 1305 Series
regulators rugged and corrosion-resistant.
—Removing the regulator union
nut (see Figure 2) allows valve disk maintenance
while inlet adaptor remains in pipeline.
—With brass and
stainless steel construction, 1305 Series regulators
handle up to 4000 psig (276 bar) inlet pressure
at 100°F (38°C).
Freeze-up—Design of nned inlet adaptor allows
warming of reduced pressure gas.
materials are available for applications handling
sour gases. These constructions comply with the
recommendations of NACE International Standards
MR0175 and MR0103.
Like most regulators, the 1305 Series have outlet
pressure ratings lower than their inlet pressure ratings.