Data Sheet

Bulletin 71.1:67D
5
Principle of Operation (Figure 2)
Downstream pressure is registered internally on the lower side of
the diaphragm. When the downstream pressure is at or above
the set pressure, the valve plug is held against the ori ce and
there is no  ow through the regulator. When demand increases,
downstream pressure drops slightly allowing the spring to
extend, moving the stem down and the valve plug away from the
ori ce. This allows  ow through the regulator.
Internal Relief
(Types 67DR, 67DSR, 67DFR, and 67DFSR)
If for some reason, outside of normal operating conditions,
the downstream pressure exceeds the setpoint of the
regulator, the force created by the downstream pressure
will lift the diaphragm until the diaphragm is lifted off the
relief seat. This allows  ow through the token relief. The
relief valve on the Type 67DR, 67DSR, 67DFR, or 67DFSR
is an elastomer plug that prevents leakage of air from
the downstream to atmosphere during normal operation,
thereby conserving plant air.
Smart Bleed™ Airset
In some cases, it is desired to exhaust downstream pressure
if inlet pressure is lost or drops below the setpoint of the
regulator. For example, if the regulator is installed on
equipment that at times has no  ow demand but is expected
to back ow on loss of inlet pressure. The Type 67DFR or
67DFSR can be ordered with the Smart Bleed option which
includes an internal check valve for this application. During
operation, if inlet pressure is lost, or decreases below the
setpoint of the regulator, the downstream pressure will back
 ow upstream through the regulator and check valve. This
option eliminates the need for a  xed bleed downstream of
the regulator, thereby conserving plant air.
Note
During normal operation the check valve’s metal
to metal seat allows limited  ow through the
regulator from the inlet to outlet, even when
there is no downstream demand. To prevent
downstream pressure buildup, the Smart Bleed
option is only avilable with the internal relief
version of the 67 Series.
Installation
The 67D Series regulators may be installed in any position.
Spring case vents must be protected against the entrance
of rain, snow, debris, or any other foreign material that might
plug the vent openings. The inlet connection is marked “In”
and the main outlet connection is marked “Out”. If a pressure
gauge is not installed in one of the two secondary outlet
connections, plug the unused connections. See Figures 4
and 5 for dimensions.
Emerson Process Management Regulator Technologies,
Inc. provides an instruction manual with every regulator
shipped. Refer to this for complete installation, operation and
maintenance instructions. Included is a complete listing of
individual parts and recommended spare parts.
Figure 2. 67D Series Operational Schematics
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
M1153
M1154
TYPE 67DR OR 67DSR TYPE 67DFR OR 67DFSR
TYPE 67D OR 67DS
TYPE 67DF OR 67DFS
Type XXXX
MXXXX
Month Year
Type XXXX
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
INTERMEDIATE PRESSURE
PILOT SUPPLY PRESSURE
LOADING PRESSURE
SMART BLEED™ OPTION FOR
TYPE 67DFR OR 67DFSR