Pneumatic Control Valve Assembly Type 3331/3278 Fig. 1 Type 3331/3278 Pneumatic Control Valve Assembly 1. Design and principle of operation The pneumatic control valve assembly consists of a Type 3331 Butterfly Valve and a Type 3278 Pneumatic Rotary Actuator. This control valve assembly is designed for both control and on-off operation for use in process engineering and industrial installations. It is especially suitable for liquids, steams and gases at temperatures ranging from 10 C to +450 C and nominal pressures from PN 10 to PN 40 bar. Depending on the particular application, the butterfly valve (orderable in nominal sizes DN 100 to DN 400) can be optionally designed with a swing-through, step-seated or angleseated/low-noise orifice plate. A symbol on the nameplate of the butterfly valve specifies the respective version. Edition October 1993 Mounting and operating instructions EB 8227 E
The process medium flows through the butterfly valve in the direction indicated by an arrow. In this respect, the supply pressure acting on the rotary actuator determines the position (i.e. opening angle) of the orifice plate (8) and therefore the flow across the free area between the orifice plate and body (1). The shaft (4) with attached orifice plate is connected to the actuating shaft via a lever system and sealed by means of a double stuffing box packing (5). Forces are transmitted from the actuator to the vane via a feather key (4.1) on the shaft. The failure action of the control valve upon supply failure (supply pressure) is determined by the way the rotary actuator is attached to the butterfly valve, either flange 1 or 2 of body. Failure action: "fail-close" The actuator springs close the butterfly valve when pressure acting on the rotary actuator is relieved and upon supply failure. The butterfly valve opens with increased supply pressure against the force of the actuator springs. Failure action: "fail-open" The actuator springs open the butterfly valve when pressure acting on the rotary actuator is relieved and upon supply failure. The butterfly valve closes with increased supply pressure against the force of the actuator springs. 1 Body 2 Gland of stuffing box 3 Yoke 4 Shaft 4.1 Feather key 5 Packing 6 Spring 7 Plug pin 8 Orifice plate 9 Interior bearing 10 Screwed plug 11 Test connection (special version) 12 Signal pressure connection 13 Diaphragm 14 Spring(s) 15 Actuator stem 16 Actuator shaft 17 Screws 18 Adjusting screw Fig. 2 Sectional Diagram Type 3331/3278 2
2. Installation 2.1 Assembly of butterfly valve and rotary actuator If the butterfly valve and actuator have not been pre-assembled at the factory, the actuator must be attached in the manner described below: If failure action "fail-close" is desired, the butterfly valve must be attached at flange 2 of the body. If failure action "fail-open" is desired, the butterfly valve must be attached at flange 1 of the body. The numeric designation, 1 or 2, is casted on the corresponding side of the body. According to customer requirements, the rotary actuator can be mounted either vertically or horizontally on the butterfly valve using the four featherkey keyways of the actuator shaft (15), each shifted 90. Failure action: "fail-close" Procedure: 1. Completely unloosen the two adjusting screws (18.1 and 18.2) on the rotary actuator, and tighten the adjusting screw (18.2) until the actuator shaft (15) and corresponding slots are vertical or horizontal to the actuator shaft. 2. Place the orifice plate (8) of the butterfly valve in the closing position (0 angle of rotation). 3. Push the actuator with shaft over the shaft (4) and tightly screw together the actuator and vane using the four associated screws (17). 4. Loosen the adjusting screw (18.2) again, and apply the supply pressure which corresponds to the lower-limit value of the spring range (see nameplate) to the signal pressure connection (12). 5. Loosen or tighten the adjusting screw for the closing position (18.2) so that the butterfly valve is completely closed (stepseated vanes require a certain amount of clearance). 6. Apply the upper-limit value of the spring range to the signal pressure connection (12), and tighten the other adjusting screw (18.1) until the butterfly valve stops at a 70 angle of rotation (for control operation). If applicable, observe the angle indicator on the vane or positioner. 7. Secure the position of the two adjusting screws using the matching lock nuts. 8. Make note of the set angle of rotation on the actuator s nameplate. Failure action:"fail-open" Procedure: 1. Completely unloosen the two adjusting screws (18.1 and 18.2) on the rotary actuator, and tighten the adjusting screw (18.1) until the actuator shaft (15) and corresponding slots are vertical or horizontal to the actuator shaft. 2. Place the orifice plate (8) of the butterfly valve in the opening position (90 angle of rotation). 3. Push the actuator with shaft over the shaft (4) and tightly screw together the actuator and shaft using the four associated screws (17). 4. Loosen the adjusting screw (18.1) again and apply the supply pressure which corresponds to the upper-limit value of the spring range (see nameplate) to the signal pressure connection. 5. Loosen or tighten the adjusting screw (18.1) so that the butterfly valve is completely closed (step-seated vanes require a certain amount of clearance). 6. Apply the lower-limit value of the spring range to the signal pressure connection (12), and screw in the other adjusting screw (18.2) until the butterfly valve stops at a 70 angle of rotation (for control operation). If applicable, observe the angle indicator on the vane or positioner. 7. Secure the position of the two adjusting screws using the matching lock nuts. 8. Make note of the adjusted angle of rotation on the actuator s nameplate. 3
2.2 Mounting position The control valve can be installed either horizontally or vertically in the pipeline. However, note the following in regard to the direction of flow: The butterfly valve is to be installed in the pipeline in such a way that the lower half of the orifice plate is opened in the direction of flow. This type of installation prevents dirt deposits from accumulating, which could obstruct the orifice plate when it is to be opened. For the angle-seated/low-noise butterfly valve utilizing the serrated orifice plate, it must always be installed in the direction of flow, indicated by the arrow on the butterfly valve s body. When assembling the control valve between the flange of the pipeline, the orifice plate must be positioned to CLOSE, and special care must be taken not to damage the packing strips. When tightening the bolts of the flanges, make certain that the flat packings are pressed equally on all sides. The orifice plate must be installed in the pipeline, allowing for free movement without restrictions. 2.3 Test connection For butterfly valves provided with a test connection for checking the leakage of the stuffing box (distinguished by a shield and a screwed plug with hexagon insert bit), an appropriate method of leakage detection should be provided such as, for instance, 1) contact-making pressure gauge, 2) drain in an open receptacle or 3) inspection glass. 2.4 Signal pressure connection The signal pressure connection of the rotary actuator is designed as a tapped hole with G 1 4 female thread. This type of connection allows a solenoid valve (according to VDI/VDE 3845) to be connected, eliminating additional piping. Combined with SAMSON Type 3766 and 3767 Positioners, a prefabricated pipe-joint connection including connecting plate is available as accessory equipment for the connection above. 3. Operation 3.1 Stuffing box Stuffing box versions for temperatures up to 220 C are equipped with a self-adjustable double stuffing box packing. For higher temperatures up to plus 450 C, this packing can be tightened and should be carefully re-adjusted by spanning the gland of the stuffing box (2) when putting the system into operation. 3.2 Changing the failure action ("fail-close" to "fail-open") The failure action can consequently be changed from "fail-close" to "fail-open" and vice versa. For this purpose, the attachment side of the rotary actuator must be correspondingly changed from flange 2 to 1 and vice versa on the body. The procedure for changing the failure action is described in detail in section 2.1. Additional information on how, for example, to change the spring range in order to obtain other driving torques can be found in the technical description "Mounting and operating instructions EB 8321 E" of the rotary actuator. 3.3 Disassembling the control valve CAUTION: Before the control valve can be disassembled, the corresponding system component must first be relieved of pressure and drained. Always assure that the orifice plate is positioned to CLOSE when disassembling the butterfly valve. 4. Accessories When attaching (according to VDI/VDE 3845) another make positioner other than a SAMSON model, an adapter kit is required on side of the actuator containing a free flange end; i.e., side opposite to the butterfly valve. This adapter kit contains a fastening angle, intermediate piece, plus the required mounting screws. 4
Adapter kit: For actuator effective area 160 cm 2 Order no.: 1400-5890 For actuator effective area 320 cm 2 Order no.: 1400-5891 5. Dimensions in mm and weights Type 3331 Butterfly Valve Nominal size DN 100 150 200 250 300 400 Ø W 16 16 25 16 25 25 25 36 25 36 A 52 56 60 68 78 102 B 136 175 202 241 267 338 C 307 348 380 373 405 438 514 506 559 551 Ø D i 97 146 194 242 290 380 Ø D o 158 216 270 320 376 486 Actuator Effective diaphragm 2 surface cm 160 160 320 160 320 320 320 320 Ø D 225 225 295 225 295 295 295 295 E 62 62 84 62 84 84 84 84 H1 258 258 419 258 419 419 419 419 H2 72 72 95 72 95 95 95 95 Weight (approx. kg) 31 37 75 43 81 90 108 151 H2 = Dimension excluding adjusting screws 5
6. Customer inquiries (please indicate the following information) 1. Order number (numeric designation on the nameplate) 2. Type, product number, nominal size DN and control valve version 3. Pressure and temperature of the process fluid 4. Rate of flow in m 3/ h 5. Signal pressure range (actuator spring range) 6. Installation schematic SAMSON AG MESS- UND REGELTECHNIK Weismüllerstraße 3 D-60314 Frankfurt am Main Postfach 10 19 01 D-60019 Frankfurt am Main Telefon (0 69) 4 00 90 Telefax (0 69) 4 00 95 07 EB 8227 E