Data Sheet
Bulletin 71.2:299H
4
Introduction
Description
!
WARNING
Since a pilot-operated regulator is
constructed of both a pilot and a main
valve, do not exceed the maximum inlet
pressure shown on the nameplate.
The 299H Series pressure reducing regulators provide
a broad capacity of controlled pressure ranges and
capacities in a wide variety of distribution, industrial
and commercial applications. A 299H Series regulator
has a pilot integrally mounted to the actuator casing.
The 299H Series regulators can handle inlet pressures
up to 175 psig / 12.1 bar depending on orice size.
The integral token relief on the Types 299HR and
299HSR regulators is located in the pilot and
alerts you to an increase in downstream pressure
beyond the regulator setpoint.
The Type 299HS provides overpressure or
overpressure and underpressure protection by
completely shutting off the ow of gas to the
downstream system. It comes with a Type VSX-2
slam-shut device which can be congured for
Ovepressure Shutoff (OPSO) or Overpressure and
Underpressure Shutoff (OPSO/UPSO). The slam-shut
device’s actions are independent of the main valve
and of variations to the inlet pressure. The Type VSX-2
slam-shut device has internal or external registration.
External registration requires a downstream
sensing line.
Options
P590 Series Pilot Supply Filter
The optional P590 Series pilot supply lter prevents
pipeline debris from entering the pilot; a primary cause
of pilot clogging. When the upstream system is free of
debris, the 299H Series regulators may be installed
without a pilot supply lter.
Type 67CF Filtered Pilot Supply Regulator
When it is necessary to install a pilot supply regulator,
an optional Type 67CF ltered pilot supply regulator
may be installed. For example, on applications with
inches of water column setpoints and inlet pressure
variations of more than ±20 psig / ±1.4 bar it may
be necessary to install a Type 67CF to maintain
published accuracy.
Principle of Operation
Letter keys in this section refer to Figure 3 unless
otherwise noted. Fast response and accuracy are made
possible by the amplifying effect of the pilot and by the
two-path control system. The function of the pilot is
to sense change in the controlled outlet pressure and
amplify it into a larger change in the loading pressure.
Any changes in outlet pressure act quickly on both the
actuator diaphragm and the loading pilot, thus providing
the precise pressure control and fast speed of response
that is characteristic of a two-path system.
Upstream or inlet pressure is utilized as the operating
medium, which is reduced through pilot operation to
load the main diaphragm chamber. Tubing connects
the inlet pressure to the pilot. Downstream or outlet
pressure registers underneath main diaphragm (E) and
on top of pilot diaphragm (F). There are three different
versions of pressure registration for the Type 299H.
Internal registration (screws and O-rings (J)
removed)—Outlet pressure is registered through the
throat to the main diaphragm chamber and through a
small port (G) to the top of the pilot diaphragm. Internal
registration is used for ease of installation. Capacity
is somewhat limited because of droop and/or boost
associated with sensing pressure within the body.
External registration—Screws and O-rings (J) block
the throat and a downstream control line is connected to
the pilot diaphragm chamber which is connected to the
lower main diaphragm chamber by a small port (G). The
other end of the control line connects to the downstream
pipeline. External registration is used for higher capacity
and/or the upstream regulator in a monitor set. It also
allows monitoring for inlet pressures over 66 psig /
4.5 bar. Capacity is increased because of better
registration of pipeline pressure when a control line is
used. The alternate 3/4 NPT control line connection
(on the side of the pilot) can be used for piping
convenience, see Figures 8 and 9.
Dual registration (screws and O-rings (J) removed)—
The lower main diaphragm chamber registers outlet
pressure through the throat and the pilot diaphragm
chamber registers downstream pressure by use of
a downstream control line. The port (G) between the
chambers is blocked by inserting a screw and O-ring
(J) that was removed from the throat and the control
line runs from the pilot to the downstream pipeline. Dual
registration, with its larger orice (control line must be
piped to the primary 3/4 NPT connection on the side
of the pilot), provides an improved performance as
compared to internal pressure registration when used in
low ow rate and high pressure drop applications. It is
also used for no downstream bleed monitoring systems
with inlet pressures up to 66 psig / 45 bar.