1900 Series - Maintenance Manual

XI. Maintenance (Contd.)Determining the Correct LimitWasher LengthDetermine the correct limit washer length (see Figure 35)as follows:1. Assemble the disc (6) and disc holder (8) (installingthe bellows gasket and bellows, if applicable) asfollows:• Place the guide over the disc holder barrel andconnect the spindle (15) to the disc holder (8).• Install the eductor tube (40) in base (1), ifapplicable.• Install the adjusting ring (3) below the seat.2. Install the guide gasket (10), and insert the discassembly from Step 1 into the base (1).3. Install the bonnet gasket (12) and bonnet (11)(leaving out the spring assembly at this time).4. Tighten the stud nuts (14) to compress the bonnetgasket (12).5. Place a dial indicator on the bonnet (11) andover the spindle (15) and then zero the indicator.Measure total lift by pushing the disc (6) upward.Subtract the required lift of the valve from themeasured lift to find the required limit washer length.6. Machine the limit washer to the required length.7. Machine the inside chamfer, deburring and polishingas required.8. Disassemble the valve.ATTENTION!!Do not use an impact wrench on bellows valves.9. Install the limit washer with the chamfer downand reassemble the valve as described in Steps 2through 4.10. Measure the lift of the valve and compare it with therequired lift as given on the restricted lift nameplate(-0.000”, +0.005” [-0.000 mm, +0.127 mm]). Takeone of the following steps, based on the results, ifthe lift is not correct:• If the actual lift is less than required, machine thelimit washer as necessary to obtain the requiredlift. (Machine chamfer, deburr and polish beforeinstallation into the valve.)• If the actual lift is greater than required, obtain anew limit washer, and return to Step 7. (Machinechamfer, deburr and polish before installation intovalve.)11. Once correct lift is obtained, disassemble the valve.ATTENTION!!Ensure the limit washer has been chamfered tofit over the radius of the disc holder (8). The limitwasher must be installed so that the chamfered endis mating to the back face of disc holder.ATTENTION!!Check all dimension requirements for each valve. Donot interchange internal parts or use a different baseafter a set of parts has been custom-fit.ATTENTION!!For bellows Type D and E valves, check the outsidediameter and, if necessary, emery cloth down to.680˝ (17.3 mm) maximum diameter in order toavoid interference with the bellows threads.GuideLimit WasherDisc HolderRequired LiftMeasured LiftLimit Washer LengthGuideBellowsLimit WasherBellows RingBellows GasketDisc HolderConventionalBellowsFigure 35: Determining Lift and Limit Washer Length38 | Dresser Consolidated ®