Samson 3271 Mounting And Operating Instructions

Also see for 3271: Mounting and operating instructions Mounting and operating instructions Mounting and operating instructions Mounting and operating instructions Manual

EB 8310-6 EN 27Mounting and start-up5.2 Preloading the springsBy preloading the springs in the actuator, thefollowing can be achieved:− The thrust is increased (only actuatorswith "stem extends")− In combination with a SAMSON valve:the actuator travel range can be adaptedto a smaller valve travel rangeActuators that have already been preloadedby SAMSON without mounting the valve arelabeled correspondingly.Additionally, they can be identified by threelonger bolts with nuts protruding from thebottom diaphragm case. They allow thespring compression to be relieved evenlywhen disassembling the actuator (see sec-tion 9.3).5.2.1 Tensioning the springsRisk of actuator damage due to the springsbeing tensioned unevenly.− Distribute clamping bolts and nuts evenlyaround the circumference.− Tighten the nuts gradually in a crisscrosspattern.1. Distribute the long bolts (A22) evenlyaround the circumference.2. Screw the long nuts (A23) together withone washer (A25) onto the clampingbolts (A22) until they rest on the bottomdiaphragm case (A2).3. To tension the springs evenly, tighten thenuts (A23) gradually in a crisscross pat-tern until both diaphragm cases (A1, A2)rest on the diaphragm (A4). Hold thebold head stationary with a suitable tooland apply the tightening torque to thenuts. Observe tightening torques.4. Insert the short bolts (A20) through theintended holes on the diaphragm cases(A1, A2).5. Screw the short nuts (A21) with washers(A25) onto the bolts (A20). Observetightening torques.5.2.2 Increasing the actuatorthrustThe thrust can only be increased in actuatorswith "stem extends" direction of action. Toachieve this, the springs of the actuators canbe preloaded by up to 12.5 % (240 cm²) orby up to 25 % (350 and 700 cm²) of theirtravel or bench range.Example: Preloading is required for a benchrange of 0.4 to 2 bar. 25 % of this span cor-responds to 0.4 bar. Therefore, the signalpressure range is shifted by 0.4 bar to 0.8 to2.4 bar. The new lower signal pressurerange value is 0.8 bar and the new uppersignal pressure range value 2.4 bar.Î Write the new signal pressure range of0.8 to 2.4 bar on the actuator nameplateas the operating range with preloadedsprings.NoteNOTICE!