Data Sheet

Bulletin 71.2:299H
6
Figure 5. Type 299HS Operational Schematic
Type 299HS
E0072
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
July 2008
Type 299HS
LOADING PRESSURE
EXTERNAL REGISTRATION
INTERNAL REGISTRATION
Type 299H
In operation, assume the outlet pressure is less than
the setting of pilot control spring (A). The top side
of pilot diaphragm assembly (F) will have a lower
pressure than the setting of spring (A). Spring (A)
forces the diaphragm assembly upward, opening the
pilot orice (C). Additional loading pressure is supplied
to the top side of the main diaphragm (E).
This creates a higher pressure on the top side of
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 more gas to ow through the valve.
When the gas demand in the downstream system
has been satised, 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 orice (C). The loading pressure acting on
main diaphragm (E) bleeds to the downstream system
through a bleed restriction (H).
With a decrease in loading pressure on top of main
diaphragm (E), main spring (B) exerts an upward
force on the diaphragm post connected to main
diaphragm (E), pulling it upward. This moves the
main valve disk (K) toward its seat, decreasing ow
to the downstream system.
Type 299HR
Refer to Figure 4. The Type 299HR provides an integral
token relief valve. During an overpressure condition the
spring on the pilot post will allow the diaphragm head to
travel to the spring case. As the diaphragm head moves
a small amount of gas is relieved.
Note
The Type 299HR is not a full capacity
relief device. Approximate start-to-
discharge pressure is dependent on set
pressure, see Figure 7.
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
noticeable 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.
E0072
Type 299HS
E0072
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
July 2008
Type 299HS
LOADING PRESSURE
EXTERNAL REGISTRATION
INTERNAL REGISTRATION
Type 299HS
E0072
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
July 2008
Type 299HS
LOADING PRESSURE
EXTERNAL REGISTRATION
INTERNAL REGISTRATION