67D Series
3
Figure 2. 67D Series Operational Schematics
M1153 M1154
Type XXXX
MXXXX
Month Year
Type XXXX
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
INTERMEDIATE PRESSURE
PILOT SUPPLY PRESSURE
LOADING PRESSURE
The 67D Series direct-operated regulators are typically
used to provide constantly controlled, reduced pressures.
They are suitable for most air or gas applications.
• The Types 67D and 67DS are the standard
instrument supply regulators without a lter or
internal relief.
• The Types 67DF and 67DFS are equipped with a
lter for removing particles from the supply gas.
• The Types 67DR and 67DSR have an internal
relief valve with a soft seat for reliable shutoff with
no discernible leakage.
• The Types 67DFR and 67DFSR have a lter and
internal relief valve with a soft seat for reliable
shutoff with no discernible leakage.
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 orice 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 orice. This allows ow through the regulator.
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 backow on loss of inlet
pressure. The Type 67DFR or 67DFSR can be
ordered with the Smart Bleed
TM
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.
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