Mounting and operating instructions EB 8093 EN. Series 240 Pneumatic Control Valve for Cryogenic Temperatures. Type and

Transcription

1 Series 240 Pneumatic Control Valve for Cryogenic Temperatures Type and Fig. 1 Type 3248 Cryogenic Valve with Type 3277 Pneumatic Actuator as globe and angle valve Mounting and operating instructions EB 8093 EN Edition November 2000

2 Contents Contents Page 1. Design and principle of operation Assembling and adjusting valve and actuator Option of pretensioning the springs with version "Actuator stem extends" Actuator springs pretensioned by the manufacturer Installation Mounting position Signal pressure line Operation Reversing the operating direction Troubleshooting Replacing the stuffing box packing, seat and plug Version with divided plug stem extension Customer inquiries EB 8093 EN

3 Safety instructions Assembly, start-up and operation of the device may only be performed by trai - ned and experienced personnel familiar with this product. According to these mounting and operating instructions, trained personnel is re - ferred to individuals who are able to judge the work they are assigned to and recognize possible hazards due to their specialized training, their knowledge and experience as well as their knowledge of the relevant standards. Any hazards which could be caused by the process medium and the operating pressure are to be prevented by means of appropriate measures. Moreover, you are required to make sure that the control valve is only used in ap - plications where operating pressure and temperatures do not exceed the opera - ting values which are based on the valve sizing data submitted in the order. Proper shipping and appropriate storage are assumed. EB 8093 EN 3

4 Design and principle of operation 1. Design and principle of operation The Type 3248 Cryogenic Valve can be combined with the Type 3271 or Type 3277 Pneumatic Actuators for integral positioner attachment to form a pneumatic control valve. The valve body styles are globe or angle pattern and designed to be welded into vacuum-insulated pipelines or installed in cold-box installations. The low-temperature extension bonnet consists of a metal bellows seal located directly over the valve body and the insulating section above the bellows seal. Body, bellows seal and insulating section are welded to each other. The test connection (4.4) is used to monitor the pressure and check the tightness of the metal bellows. The process medium flows through the valve in the direction indicated by the arrow. The plug (3) is positioned by changing the signal pressure that acts on the actuator diaphragm. The plug stem (6) is connected to the actuator stem (8.1) via stem connector (7). The sealing of the plug stem is obtained via metal bellows and downstream stuffing box (4), the latter being equipped with a springloaded PTFE carbon V-ring packing (4.2). Fail-safe position: Depending on the arrangement of the springs in the actuator, the following failsafe positions are available: Actuator stem extends through spring force: Whenever the pressure is relieved from the diaphragm or the supply air fails, the springs close the valve. Actuator stem retracts through spring force: Whenever the pressure is relieved from the diaphragm or the supply air fails, the springs open the valve. Legend Fig. 2 1 Valve body 1.1 Low-temperature extension bonnet 2 Seat 3 Plug 4.1 Spring 4.2 Packing 4.3 Washer 4.4 Test connection 5 Valve bonnet 5.1 Guide bushing 5.2 Threaded bushing 5.3 Bolts 5.4 Travel indicator scale 5.5 Sealing ring 6 Plug stem 6.1 Stem connector nut 6.2 Lock nut 6.3 Plug stem extension with metal bellows and divided extension 6.3a and 6.3b 6.4 Bellows nut 6.5 Bellows flange 6.6 Guide piece 6.7 Nut(s) 6.8 Washers 7 Stem connector 8 Actuator 8.1 Actuator stem 8.2 Ring nut 8.3 Springs 8.4 Rolling diaphragm 9 Signal pressure connection 10 Vent plug 4 EB 8093 EN

5 Design and principle of operation 8.3 Type 3271 Actuator 10 Type 3277 Actuator Top section (6.3a) Nut Bottom section (6.3b) Version with divided plug stem extension, see chapter Angle valve Globe valve Fig. 2 Sectional drawings EB 8093 EN 5

6 Assembling and adjusting the valve and actuator 2. Assembling and adjusting the valve and actuator Proceed as follows, first, if the valve and actuator have not been preassembled by the manufacturer or, second, if an actuator of another size or type is to replace the original one: 1. Loosen the lock nut (6.2) and stem connector nut (6.1) at the valve. Press the plug and plug stem firmly into the seat. Then thread down both the stem connector nut and lock nut. 2. On the actuator (8), remove the clamps of the stem connector (7) as well as the ring nut (8.2). 3. Slide the ring nut over the plug stem extension. 4. Place the actuator on the valve bonnet (5) and secure with the ring nut (8.2). 5. Read off the bench range (or signal pressure range with pretensioned springs) and the type of fail-safe action indicated on the nameplate. The type of fail-safe action "Actuator stem extends" or "Actuator stem retracts" is indicated by FA or FE for Type 3271, and by a symbol on the nameplate for the Type The lower range value of the signal pressure range corresponds to the lower signal pressure range to be adjusted, the upper range value corresponds to the upper signal pressure range. 6. For actuators of the type "Actuator stem extends", apply pressure corresponding to the lower range value (e.g. 0.2 bar) to the signal pressure connection located at the bottom diaphragm chamber. For actuators of the type "Actuator stem retracts", apply pressure corresponding to the upper range value (e.g. 1 bar) to the signal pressure connection of the top diaphragm chamber. 7. Turn stem connector nut (6.1) by hand until it contacts the actuator stem (8.1), then turn approx. 1/4 turn further and secure this position using the lock nut (6.2). Counterhold the connector nut while you turn the lock nut, so that the plug stem extension (6.3) with the metal bellows is not twisted. 8. Attach the stem connector clamps (7) and screw them tight. 9. Align the travel indicator scale (5.4) with the tip on the side of the stem connector; for "Actuator stem extends", use lower marking (valve closed), and for "Actuator stem retracts", use upper marking. Note when disassembling an actuator! For versions of the type "Actuator stem extends", and especially for versions with pretensioned springs, the signal pressure connection must be pressurized with a pressure that is a little above the lower value of the bench range (see actuator nameplate) prior to removing the actuator. 2.1 Option of pretensioning the springs with version "Actuator stem extends" In order to obtain a more powerful thrust, the springs of these actuators can be pretensioned by 12.5 % (240 cm 2 ) or 25 % (350 and 700 cm 2 ) of their travel or signal pressure range. 6 EB 8093 EN

7 Installation If a pretension of, for example 0.1 bar, is desired for a signal pressure range of 0.2 to 1 bar, the signal pressure range is shifted by 0.1 bar to 0.3 bar. When adjusting the valve, now, a lower range pressure value of 0.3 bar must be set. The newly adjusted signal pressure range of 0.3 to 1.1 bar must be marked on the nameplate as "Signal pressure range with pretensioned springs". 2.2 Actuator springs pretensioned by the manufacturer Actuator springs that are pretensioned by the manufacturer without having attached a valve are marked by a label. These actuators have three extended bolts with nuts on the diaphragm case to enable the pre-tensioned springs to be uniformly relieved for disassembly. 3. Installation 3.1 Mounting position The valve can be mounted in any position. It must be installed free of stress. If needed, support the pipelines near the connections. CAUTION! When the valve body is welded into the pipeline, the actuator should be loaded with signal pressure for control valves equipped with the actuator version "Actuator stem extends" (fail-safe position valve closed) so that the valve plug moves from the seat in order to prevent the trim from being damaged due to excessive temperatures. IMPORTANT! Remove the protective plug from the test connection (4.4), so that the metal bellows (6.3) can be tested for potential leakage. 3.2 Signal pressure line For valves with actuator version "Actuator stem extends", connect the signal pressure line to the bottom diaphragm chamber, whereas for valves with actuator version "Actuator stem retracts", to the top diaphragm chamber. For the Type 3277 Actuator, the bottom connection is located on the side of the yoke of the bottom diaphragm case. EB 8093 EN 7

8 Troubleshooting 4. Operation 4.1 Reversing the operating direction (Fail-safe position of pneumatic actuator.) Please refer to the Mounting and operating instructions of the respective actuators as follows: EB 8310 EN for Type 3271 and EB 8311 EN for Type Troubleshooting If external leakage occurs, the metal bellows (6.3) and the packing (4.2) may be defective. If the valve does not seal properly, the tight shut-off may be prevented by dirt or other impurities built up between the seat and plug, or else by damaged sealing edges. We recommend that you disassemble the parts, thoroughly clean them and, if necessary, replace them. When carrying out maintenance or assembly work on the control valve, you are required to depressurize and drain the corresponding part of the plant. CAUTION! Temperatures may be too high, let respective part of the plant cool down first. 5.1 Replacing the stuffing box packing, seat and plug Disassembling the actuator Prior to any type of work on the valve body, you are required to disassemble the actuator first. IMPORTANT! For actuators of the type "Actuator stem extends" and especially for versions with pretensioned springs, the signal pressure connection must be pressurized with a pressure that is a little above the lower value of the bench range (see actuator nameplate) prior to removing the actuator. 1. Remove the clamps of the stem connector (7) between actuator stem and plug stem, and unscrew the ring nut (8.2). 2. Lift the actuator off the valve. CAUTION! To avoid damaging the metal bellows, it is absolutely required that no torque be transmitted to the bellows that is welded to the plug stem extension (6.3, 6.3b). Packing 1. Position a wrench on the stem connector nut (6.1) for counterhold, and loosen the lock nut (6.2). Unscrew both nuts. 2. Unscrew the threaded bushing (5.2) to release the tension from the packing. 3. Remove the nuts (5.3) from the bonnet (5), and remove the bonnet from the 8 EB 8093 EN

9 Troubleshooting flange of the low-temperature extension (1.1) towards the top. 4. Unscrew the threaded bushing (5.2) and remove the packing rings (4.2), washer (4.3) and spring (4.1), using an appropriate tool. Replace damaged parts. Clean packing chamber thoroughly. Plug: CAUTION! Do not twist bellows. 1. Unscrew the bellows nut (6.4) using a SAMSON socket wrench and pull out the plug stem extension together with the bellows seal, guide piece (6.6) and plug stem including plug from the lowtemperature extension bonnet. 2. Clamp down the plug stem extension with a suitable tool Unthread the plug from the extension. 4. Loosen the nut (6.7). Unscrew the guide piece (6.6). In case of larger nominal sizes, unscrew second nut and remove guide piece. 5. Apply lubricant (order no ) to plug stem threading of the new or reworked plug. 6. Place the guide piece (6.6) on the plug extension and turn it all the way to the end of the thread. Secure with nut (6.7), i.e. slide guide piece on and then secure with two nuts. 7. Check whether the two washers (6.8) are still in the plug stem extension. If so, screw the plug stem tightly into the bellows seal of the plug stem extension. Tightening torque: For DN 25 to 80 = 50 Nm and for DN 100 to 150 = 80 Nm. Seat: If the seat must be replaced, proceed as follows: 8. Screw the seat (2) out of the valve body using the SAMSON seat wrench. 9. Apply lubricant (order no ) to the thread of the new seat and screw in tight. Observe the tightening torques listed in the table on page Fig. 3 Packing EB 8093 EN 9

10 Troubleshooting Assembly: 1. Insert the plug stem extension together with the guide piece and the plug into the body. 2. Insert the bellows nut (6.4) and screw tight (see tightening torques according to the below table). Be sure not to twist the bellows seal! 3. Insert a new sealing ring (5.5) into the flange section. Slide the valve bonnet over the plug stem extension and place it on the flange section. 4. Screw on the nuts (5.3) and tighten. Observe tightening torques listed in Table Apply lubricant (order no ) to packing parts and threaded bushing (5.2). Slide the spring (4.1), washer (4.3) and new packing rings (4.2) over the plug stem extension into the packing chamber. Place the threaded bushing (5.2) on the extension and turn it all the way to the end of the thread. 6. Screw the lock nut (6.2) and nut (6.1) loosely onto the plug stem extension (6.3). 7. Assemble the actuator and adjust the lower and upper signal pressure range as described in chapter EB 8093 EN

11 Troubleshooting Table1 Seat wrenches and tightening torques Nominal size Seat wrench Tightening torques Nm Seat (2) DN Order no All seat ranges Reduced seat range Max. seat ranges Tightening torques Bellows nut (6.4) (values in parentheses for version made of aluminum) Tightening torques Nuts (5.3) (10) (30) (60) (100) (60) 100 EB 8093 EN 11

12 Version with divided plug stem extension 6. Version with divided plug stem extension In order to keep the overall height of the valves for cold-box applications during transportation as small as possible, control valve and bonnet must be disassembled from the flanged section of the low-temperature extension, and the plug stem extension must be secured by attaching a protective cap and a stopper. In case the following measures have not been undertaken prior to delivery, proceed as follows: For assembly and disassembly, you require special tools (order no ). Only when using the special tools, can it be ensured that the metal bellows is prevented from damage. Disassembly: IMPORTANT! For actuator versions of the type "Actuator stem extends", and especially for versions with pretensioned springs, the actuator must first be pressurized with a signal pressure that is sufficiently high to retract the actuator stem a little. 1. Remove stem connector (7) clamps between the actuator stem and the plug stem, unscrew ring nut (8.2). 2. Lift off actuator from the control valve. 3. Position a wrench on the stem connector nut (6.1), then loosen lock nut (6.2). Unscrew both nuts from the plug stem extension (6.3b). CAUTION! Do not twist the plug stem extension, otherwise the metal bellows may be damaged. 4. Loosen threaded bushing (5.2) to release the tension from the packing (4.2). 5. Remove the nuts (5.3) from the valve bonnet. Carefully remove the bonnet (5) from the flange on the low-temperature extension (1.1) towards the top. 6. Place the special tool equipped with a 24-mm socket wrench (part 1) over the plug stem extension (6.3b) in such a manner on the nut (20) that the writing "disassemble/demontieren" points towards the top. Insert socket wrench (part 2) and unscrew the top section of the plug stem extension (6.3a) using the socket wrench (part 2). 7. For sizes DN 100 and 150 (4" and 6"), unscrew the nut (20), for sizes DN 25 to 30 (1" to 3"), the nut remains on the plug stem extension. 8. Insert O-ring (24) and protective cap (23). 9. Assemble washer (21) and nut (22). Tighten nut so that the plug stem extension is moved out to the measure h (see Table 2). Do not exceed tightening torques listed in Table 2 so as to prevent the metal bellows from being damaged. 10. Tighten nuts (refer to tightening torques listed in Table 2). 11. Put stopper (25) on. 12 EB 8093 EN

13 Version with divided plug stem extension Special tool, order no Socket wrench part 2 Socket wrench part 1 h b 5.3 Nut 6.3b Bottom section of the plug stem extension 20 Nut 21 Washer 22 Nut 23 Protective cap 24 O-ring 25 Stopper Fig. 4 Assembly of protective cover (for cold-box version) Assembly After transportation, the control valve must be reassembled as follows. 1. Remove stopper. 2. Remove nut (22) and washer (21). 3. Loosen nuts (5.3) and remove protective cap (23). 4. For valve sizes DN 100 and 150 (4" and 6"), screw the nut (20) all the way down fingertight. 5. Screw top section of the plug stem extension (6.3a) fingertight onto the thread of the bottom section (6.3b). 6. Place special tool equipped with a 24- mm socket wrench (part 1) on the extension so that the writing "assemble/montieren" points towards the top. Insert socket wrench (part 2) and tighten top section of the plug stem extension (6.3a) using the socket wrench (part 2). (Tightening torque 80 Nm). 7. Insert sealing ring (5.5) into the flanged section. Slide bonnet carefully over the plug stem extension (6.3a) onto the flanged section so as to prevent the packing from being damaged. 8. Screw on nuts (5.3) and tighten. Observe tightening torques according to Table 1. Table 2 Permissible tightening torques Nm/lbf Measure h Nominal size Nut (22) Nut (5.3) mm / inch Class 150/300 Class / 1...3" 8/6 20/15 30/22 15 / / 4...6" 50/37 100/74 50/37 26 / 1 EB 8093 EN 13

14 Customer inquiries 9. Tighten threaded bushing (5.2) all the way until it does not go any further. 10. Screw lock nut (6.2) and nut (6.1) loosely onto the plug stem extension (6.3a). 11. Assemble actuator and adjust lower and upper signal range as described in chapter Customer inquiries Should you have any inquiries, please submit the following details: Type and order number (stamped on the nameplate) Production number, nominal size and version of the valve Pressure and temperature of the process medium Flow rate in m 3/ h Bench range (signal pressure range) (e.g. 0.2 to 1 bar) of the actuator Installation drawing NOTE: For data regarding the dimensions and the weight of the individual valve versions, please refer to the Data Sheet T 8093 EN. 14 EB 8093 EN

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