2
The regulator is operated by initial steam or fluid pres-
sure. It is normally closed, being held so by initial pres-
sure on the disc and by an internal main spring. When
the pilot is opened (see pilot instructions), initial pres-
sure flows through the pilot to the No. 8B tee.
Bleedport No. 4A restricts the flow and pressure
builds under the diaphragm and opens the main valve.
The No. 5A elbow steadies the operation of the regu-
lator.
Delivery pressure feeds back through the control pipe
to the pilot diaphragm. As this pressure approaches a
balance with the thrust of the adjusting spring, the
pilot throttles the loading pressure. In turn, the main
valve takes a position established by the loading pres-
sure where just enough steam flows to maintain the
set delivery pressure.
CONDENSATE CHAMBER
Main valves with large internal volumes, or valves used
in relatively high pressure or superheat, may require
more water than can be condensed from radiation
alone. Live steam will rapidly degrade the rubber
diaphragm of an E5 and generally yield poor control in
other main valves. To prevent this from happening, the
Condensation Chamber and the base are primed with
water before start-up. As the pilot opens, medium
pressure steam flows to the Condensation Chamber
condensing the vapor in the presence of the prime and
larger radiational area. The condensate exits the
chamber through a No. 5B Open Elbow directed to the
No. 5A Restriction Elbow in the hood. This condensate
collecting under the diaphragm creates a loading
pressure which forces the valve open.
OPERATING PRINCIPLE
Globe Valve
Gate Valve
Long
Radius
Elbow
D2
Gate Valve
At least 20 Pipe Diameters (D2)
To first turn or secondary PRV on control valve
At least 10 Pipe Diameters (D1)
Straight run, full size
Avoid bull-headed connection to
low pressure steam main when
reduction in noise level is important
Strainer
Gate Valve
D1
Drip and Trap
Do not insulate
below this line or any
part of the pilot
1/4" Sensing Pipe - Pitch away
from Pilot. Avoid water pockets
connect to D2 pipe where shown
Spence Pressure Regulator
- allow clearance above
and below for maintenance.
4 Pipe diameters
(D2) Minimum
Drip and trap ahead
of rise in piping or
secondary PRV or
control valve
Preferred transition - 15"
max. total included angle
RECOMMENDED INSTALLATION
FIGURE 2
