Fisher MR95L - Principle of Operation; For Types MR95 H, MR95 L, MR95 HP and MR95 HT Pressure Reducing Regulators

MR95 Series
4
Figure 2. MR95 Series Operational Schematics
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
SPRING
GASKET
METAL DIAPHRAGMS
TYPE MR95H WITH 2 METAL DIAPHRAGMS (ALSO TYPICAL OF
TYPES MR95HT AND MR95L EXCEPT FOR TYPE MR95L WITH 1/4 NPT
BODY SIZE, 2 to 6 psi / 0.14 to 0.41 bar RANGE)
SPRING
GASKET
METAL DIAPHRAGM
TYPE MR95L (1/4 NPT, 2 to 6 psi / 0.14 to 0.41 bar RANGE)
WITH METAL DIAPHRAGM
CONTROL LINE TAP
FRONT AND INTERNAL VIEW OF
TYPE MR95H WITH INTERNAL
PRESSURE REGISTRATION
BACK VIEW OF
1/2 IN. / DN 15 TYPE MR95H
WITH EXTERNAL
PRESSURE REGISTRATION
SIDE AND INTERNAL VIEW OF
3/4 TO 2 IN. / DN 20 TO 50
TYPE MR95H WITH EXTERNAL
PRESSURE REGISTRATION
(ALSO TYPICAL OF TYPE MR95L,
1/2 TO 2 IN. / DN 15 TO 50 BODY SIZES)
Principle of Operation
For Types MR95H, MR95L,
MR95HP and MR95HT
Pressure Reducing Regulators
Types MR95L, MR95H, MR95HP and MR95HT
(see Figure 2) are direct-operated regulators
and use spring force to regulate outlet pressure.
Downstream pressure is registered either internally
through the body or externally through a control
line to the under side of the diaphragm. When the
downstream pressure is at or above the set pressure,
the disk is held against the orice and restricting
ow through the regulator. When demand increases,
downstream pressure drops slightly allowing the spring
to extend, moving the stem down and the disk away
from the orice. This allows uid ow through the body
to the downstream system.
ADJUSTING SCREW
CONTROL SPRING
DIAPHRAGM
PITOT TUBE
VALVE PLUG
STEM