This creates a higher pressure on the top side of the
main diaphragm (E) than on the bottom side, forcing
the diaphragm downward. This motion is transmitted
through a lever, which pulls the valve disk (K) open,
allowing inlet pressure to flow through the valve.
When the demand in the downstream system has been
satisfied, the outlet pressure increases. The increased
pressure is transmitted through the downstream control
line (for external or dual registration) or through the
port (G) (for internal registration) and acts on top of the
pilot diaphragm (F). This pressure exceeds the pilot
spring setting and forces the diaphragm down, closing
the orifice (C). The loading pressure acting on the
main diaphragm (E) bleeds to the downstream system
through a bleed restriction (H).
With a decrease in loading pressure on top of the
main diaphragm (E), the main closing spring (B)
exerts an upward force on the diaphragm post which
is connected to the main diaphragm (E), pulling it
upward. This moves the main valve disk (K) toward its
seat, decreasing flow to the downstream system.
Type 299HR
During normal operation the Type 299HR performance
is identical to the Type 299H. If an overpressure
condition occurs, the pilot diaphragm head will
separate from the pilot diaphragm post and travel until
it contacts the pilot spring case. The movement of the
diaphragm head creates a path and a token or small
amount of gas will be released.
When the overpressure condition ceases, the pilot
diaphragm head will return to the diaphragm post and
the regulator will return to normal operation.
Type 299HS or 299HV
The Type VSX2 (299HS) or VSX8 (299HV) slam-shut
device on the Type 299HS or 299HV regulator is a fast
acting slam-shut valve which provides overpressure or
overpressure and underpressure protection by completely
shutting off the flow of gas to the downstream system.
The slam-shut module’s actions are independent of
the Type 299HS or 299HV main regulator and of the
variations to the inlet pressure. The Types VSX2 and
VSX8 have internal or external registration. External
registration requires a downstream sensing line.
Figure 2.
299H Series Operational Schematics (continued)
TYPE 299HV
Type 299HV
LOADING PRESSURE
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
EXTERNAL REGISTRATION
INTERNAL REGISTRATION
September 2016
Type 299HV
Type 299HV
LOADING PRESSURE
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
EXTERNAL REGISTRATION
INTERNAL REGISTRATION
September 2016
Type 299HV
Type 299HV
LOADING PRESSURE
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
EXTERNAL REGISTRATION
INTERNAL REGISTRATION
September 2016
Type 299HV
E0072_09/2016
Type 299HS
E0072
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
July 2008
Type 299HS
LOADING PRESSURE
EXTERNAL REGISTRATION
INTERNAL REGISTRATION
5
299H Series
