Type 3271 and Type 3277 Pneumatic Actuators - SAMSON

1 Type 3271 and Type 3277 Pneumatic ActuatorsActuator areas: 175 and 750 cm Mounting andOperating InstructionsEB 8310-5 ENEdition October 2013 Type 3271 and Type 3277 Pneumatic ActuatorsType 3271 Type 3277 ContentsPage1 Design and principle of operation.. attachment in combination with Type 3277 .. of action .. pressure routing in Type 3271 .. pressure routing in Type 3277 .. action .. stem extends .. stem retracts .. 62 Type of application.. service .. service .. 73 Versions.. version .. with adjustable mechanical travel stop.

2 With handwheel .. 74 Operation.. with mechanical travel stop .. travel limit .. travel limit .. with handwheel .. the valve travel .. 105 Maintenance.. the actuator .. preloaded springs .. the diaphragm plate assembly .. the diaphragm plate assembly .. (depending on direction of action) .. the position of the slotted nut .. seals and bearings .. 3271 .. 3277 .. with travel stops .. with handwheel .. the actuator .. 182EB 8310-5 the direction of action (fail-safe action) .. 196 Nameplate.. 207 Dimensions and weights.

3 208 Customer inquiries.. 21EB 8310-5 EN3 ContentsGeneral safety instructions4 The Actuators may only be mounted, started up and operated by trainedand experienced personnel familiar with this to these mounting and operating instructions, trained personnelrefers to individuals who are able to judge the work they are assigned toand recognize possible hazards due to their specialized training, theirknowledge and experience as well as their knowledge of the relevant hazards which could be caused by the signal pressure and movingparts of the actuator are to be prevented by means of appropriate shipping and appropriate storage are SAMSON Type 3271 and Type 3277 Pneumatic Actuators are mounted onSAMSON Series 240, 250, 280 and Actuators consist of two diaphragmcases (1 and 2), a rolling diaphragm (4)with diaphragm plate (5) and springs (10).

4 The signal pressure (S) creates a force at thediaphragm surface which is counteracted bythe springs (10) arranged in the number of springs and their compres-sion determine the bench range (signal pres-sure range) whereby the rated travel is di-rectly proportional to the signal maximum of 19 springs can be installed,partly fitted inside one stem connector (27) connects the actua-tor stem (7) to the plug stem of the attachment incombination with Type 3277 This actuator version is fitted with an addi-tional yoke on the bottom diapragm 8310-5 ENDesign and principle of operation16110333652S44240341735S782741 Fig.

5 1 Sectional drawing of Type 3271 actuator stem retracts (air-to-close) actuator stem extends (air-to-open)(air applied in this diagram)This yoke is used for direct attachment of apositioner and/or limit switch to protect thetravel pick-off against external to the mounting and operating instruc-tions of the valve accessories to be mountedfor more details on attachment and the re-quired mounting of actionThe direction of action is determined by howthe springs and diaphragm plate are ar-ranged in the actuator . For fail-safe action" actuator stem retracts" (air-to-close), thesignal pressure is connected to the loadingpressure connection on the top diaphragmcase (1) or (75) for the version with mechan-ical travel 8310-5 EN5 Design and principle of operation1611033365222S44234403517782742 41 SFig.

6 2 Sectional drawing of Type 3277 Legend for Figs. 1 and 21 Top diaphragm case2 Bottom diaphragm case4 Diaphragm5 Diaphragm plate7 actuator stem8 Nut10 Springs16 Vent plug17O-ring22 Bolt27 Stem connector33 Nut34 Slotted nut35 Retainer36 Spacing tube40 Shaft sealing ring41 Wiper42 Plain bearingSLoading pressureconnectionActuator stem retracts (air-to-close) actuator stem extends (air-to-open)(air applied in this diagram)For fail-safe action " actuator stem extends"(air-to-open), the signal pressure is con-nected to the loading pressure connectionon the bottom diaphragm case (2).

7 The Actuators 's direction of action can bechanged. To change it, the actuator mustfirst be removed from the valve (refer to sec-tion on how to reverse the direction ofaction). Signal pressure routing inType 3271In the Type 3271 actuator with the fail-safeaction " actuator stem extends"(air-to-open), (Fig. 1, right), the signal pres-sure is connected to the bottom loadingpressure connection (S) to fill the bottom dia-phragm chamber with air, causing the actu-ator stem to move upwards, opposing theforce of the actuator the Type 3271 actuator with the fail-safeaction " actuator stem retracts" (air-to-close),(Fig.)

8 1, left), the signal pressure is connectedto the top loading pressure connection (S) tofill the top diaphragm chamber with air,causing the actuator stem to movedownwards, opposing the force of the actu-ator Signal pressure routing inType 3277In the Type 3277 actuator with the fail-safeaction " actuator stem extends"(air-to-open), (Fig. 2, right) the signal pres-sure is connected to the loading pressureconnection at the side of yoke and routedthrough an hole in the yoke to fill the bottomdiaphragm chamber with air, causing theactuator stem to move upwards opposingthe force of the actuator positioner can be connected in this caseby using a connection block.

9 Additional pip-ing to the actuator is not required (readpositioner documentation for more details).In the Type 3277 actuator with the fail-safeaction " actuator stem retracts" (fail-to-close)(Fig. 2, left) the signal pressure is connectedto the top loading pressure connection (S) tofill the top diaphragm chamber with air,causing the actuator stem to move down-wards, opposing the force of the actionWhen the signal pressure fails, the fail-safeaction of the actuator depends on whetherthe springs are installed in the top or bottomdiaphragm actuator stem extendsWhen the signal pressure is reduced or theair supply fails.

10 The springs move the actua-tor stem downwards and close the valve opens when the signal pressure isincreased enough to overcome the force ex-erted by the actuator stem retractsWhen the signal pressure is reduced or theair supply fails, the springs move the actua-tor stem upwards and open the valve. Thevalve closes when the signal pressure is in-creased enough to overcome the force ex-erted by the 8310-5 ENDesign and principle of operation2 Type of applicationNote:Refer to the mounting and operatinginstructions of the corresponding valve formore details on how to mount the actuatoron the valve or how to remove serviceThe Type 3271 and Type 3277 PneumaticActuators are designed for a maximum sup-ply pressure of 6 serviceTo prevent the actuator from being dam-aged, do not let the supply pressure exceedthe upper spring range value by more than3 bar when the actuator is used for on/offservice with the fail-safe action "Actuatorstem retracts" (air-to-close).