Submitted by divya on July 8, 2025

DFC & DFO Linear Spring & Diaphragm Actuators

3-15 PSIG (0.21-1.03 BARG) or 6-30 PSIG (0.41-2.07 BARG) Input Signal
3/8" (9.5mm) | 1/2" (12.7mm) | 3/4" (19.1mm) Valve Stem Compatibility
2-1/8" (54mm) | 2-13/16" (71mm) | 3-9/16" (90mm) Yoke Boss Size
-40°F to 180°F (-40°C to 82°C) Standard Temperature Limitations

Model DFC (Fail Closed) and DFO (Fail Open) linear spring and diaphragm actuators are large diaphragm area actuators that allow for low-pressure operation. The spring provides fail safe positioning for a control valve on loss of pneumatic supply pressure. Both DFC and DFO actuators can be used to automate control valves for throttling or on/off control of liquids or gases.

Overview

Options

Open Yoke / Open Valve Stem Design
Heavy Duty Protective Coatings Available
Handwheels and Travel Stop Options Available
Versatile Instrument Mounting Options

Product Specifications

DFC / DFO Specifications

DFC Actuator Specifications

DFC ACTUATOR SPECIFICATIONS
SPECIFICATIONS			ACTUATOR SIZE
SPECIFICATIONS			1046	1069	2069	2105	2156	3105	3156	3220 (1)
NOMINAL EFFECTIVE AREA		INCH2	46	69	69	105	156	105	156	220
NOMINAL EFFECTIVE AREA		cm2	297	445	445	667	1,006	677	1,006	1,419
YOKE BOSS SIZE		INCH	2-1/8	2-1/8	2-13/16	2-13/16	2-13/16	3-9/16	3-9/16	3-9/16
YOKE BOSS SIZE		cm	54	54	71.5	71.5	71.5	90.5	90.5	90.5
ACCEPTABLE VALVE STEM DIAMETER		INCH	3/8	3/8	1/2	1/2	1/2	3/4	3/4	3/4
ACCEPTABLE VALVE STEM DIAMETER		mm	9.5	9.5	12.7	12.7	12.7	19.1	19.1	19.1
MAXIMUM ALLOWABLE OUTPUT THRUST		lb	2,300	2,300	2,700	5,650	7,550	5,650	6,800	8,800
MAXIMUM ALLOWABLE OUTPUT THRUST		N	10,230	10,230	12,010	25,132	33,584	25,132	30,248	39,144
MAXIMUM TRAVEL (2)	STANDARD	INCH	3/4	1-1/8	1-1/2	2	2	2	2	3 (3)
	STANDARD	mm	19.1	28.6	38.1	50.8	50.8	50.8	50.8	76.2
	TOP-LOADED	INCH	N/A	3/4	N/A	3/4	N/A	N/A	1-1/8	N/A
	TOP-LOADED	mm	N/A	19.1	N/A	19.1	N/A	N/A	28.6	N/A
MAXIMUM CASING PRESSURE FOR ACTUATOR SIZING (4,5)		PSIG	55	70	70	65	55	65	55	50
MAXIMUM CASING PRESSURE FOR ACTUATOR SIZING (4,5)		BARG	380	483	483	448	379	448	379	345
MAXIMUM EXCESS DIAPHRAGM PRESSURE (4)		PSIG	55	20	20	10	10	10	10	10
MAXIMUM EXCESS DIAPHRAGM PRESSURE (4)		BARG	380	138	138	69	69	69	69	69
MAXIMUM DIAPHRAGM CASING PRESSURE (4,5)		PSIG	110	90	90	75	65	75	65	60
MAXIMUM DIAPHRAGM CASING PRESSURE (4,5)		BARG	760	621	621	517	448	517	448	414
MATERIAL TEMPERATURE CAPABILITIES	NITRILE		-40°F to 180°F (-40°C to 82°C)
MATERIAL TEMPERATURE CAPABILITIES	SILICONE		-40°F to 180°F (-40°C to 82°C)
NOTES:	(1)	These values also apply to the DFC Size 3220-4 actuator.
	(2)	Actuator travel may be less than the value listed after connected to the valve.
	(3)	Maximum actuator travel for the 3220-4 is 4 inches (102 mm).
	(4)	Additional pressure may be added to the actuator when the actuator is at full travel. Damage to the actuator will occur if the Maximum Excess Diaphragm Pressure is exceeded. When the actuator has reached its full travel, and the diaphragm plate is physically stopped from moving, the energy from additional pressure is transferred to the diaphragm and casing. The amount of excess pressure that can be added at full travel is limited, exceeding this limiting factor will result in damage to the actuator, leakage, and/or casing fatigue or deformation.
	(5)	This Maximum Casing Pressure is not to be used for normal operating pressure. Its purpose is to allow for typical regulator supply settings and/or relief valve tolerances. The maximum casing pressure is the pressure that can be applied to the actuator when the actuator is at less than full travel. Damage to the actuator may occur if this pressure is exceeded before the full travel is reached.

DFO Actuator Specifications

DFO ACTUATOR SPECIFICATIONS
SPECIFICATIONS			ACTUATOR SIZE
SPECIFICATIONS			1046	1069	2069	2105	2156	3105	3156	3220 (1)
NOMINAL EFFECTIVE AREA		INCH2	46	69	69	105	156	105	156	220
NOMINAL EFFECTIVE AREA		cm2	297	445	445	667	1,006	677	1,006	1,419
YOKE BOSS SIZE		INCH	2-1/8	2-1/8	2-13/16	2-13/16	2-13/16	3-9/16	3-9/16	3-9/16
YOKE BOSS SIZE		cm	54	54	71.5	71.5	71.5	90.5	90.5	90.5
ACCEPTABLE VALVE STEM DIAMETER		INCH	3/8	3/8	1/2	1/2	1/2	3/4	3/4	3/4
ACCEPTABLE VALVE STEM DIAMETER		mm	9.5	9.5	12.7	12.7	12.7	19.1	19.1	19.1
MAXIMUM ALLOWABLE OUTPUT THRUST		lbf	2,300	2,300	2,700	5,650	7,550	5,650	6,800	8,800
MAXIMUM ALLOWABLE OUTPUT THRUST		N	10,230	10,230	12,010	25,132	33,584	25,132	30,248	39,144
MAXIMUM TRAVEL (2)		INCH	3/4	1-1/8	1-1/2	2	2	2	2	3 (3)
MAXIMUM TRAVEL (2)		mm	19.1	28.6	38.1	50.8	50.8	50.8	50.8	76.2
MAXIMUM CASING PRESSURE FOR ACTUATOR SIZING (4)		PSIG	125	65	65	50	40	50	40	55
MAXIMUM CASING PRESSURE FOR ACTUATOR SIZING (4)		BARG	862	448	448	345	276	345	276	379
MAXIMUM DIAPHRAGM CASING PRESSURE (4,5)		PSIG	140	75	75	60	50	60	50	65
MAXIMUM DIAPHRAGM CASING PRESSURE (4,5)		BARG	965	517	517	414	345	414	345	448
MATERIAL TEMPERATURE CAPABILITIES	NITRILE		-40°F to 180°F (-40°C to 82°C)
NOTES:	(1)	These values also apply to the DFO Size 3220-4 actuator.
	(2)	Actuator travel may be less than the value listed after connected to the valve.
	(3)	Maximum actuator travel for the 3220-4 is 4 inches (102 mm).
	(4)	The Operating Diaphragm Pressure must not exceed the Maximum Diaphragm Casing Pressure and must not produce a force on the actuator stem greater than the maximum allowable valve stem load.
	(5)	This Maximum Casing Pressure is not to be used for normal operating pressure. Its purpose is to allow for typical regulator supply settings and/or relief valve tolerances. The maximum casing pressure is the pressure that can be applied to the actuator when the actuator is at less than full travel. Damage to the actuator may occur if this pressure is exceeded before the full travel is reached.