1900 Series - Maintenance Manual

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XI. Maintenance (Contd.)• Wipe off the old compound and replace it with newcompound frequently. Apply more pressure to speedthe cutting action of the compound.• To check the seating surfaces, remove all compoundfrom the seat and the lap. Then, shine the seat withthe same lap using the lapping method as describedabove. Low sections on the seating surface show upas shadow in contrast to the shiny portion.• If shadows are present, further lapping is necessary.Only laps known to be flat can be used. It shouldtake only a few minutes to remove the shadows.• When lapping is complete, any lines appearingas cross-scratches can be removed by rotatingthe lap on its axis (which has been wiped clean ofcompound) on the seat.• Thoroughly clean the lapped seat using a lintfreecloth and a cleansing fluid.Reconditioning of LapsRing laps are reconditioned by lapping them on a flatlapping plate in a figure-eight motion (see Figure 29). Toensure the best results, recondition the ring laps aftereach use. Use an optical flat to check the quality of thelap.LAPPING PLATERING LAPATTENTION!!Before assembly, lap the contact surfaces of thenozzle, soft-seat disc (UM DA) and O-ring retainer toprovide metal-to-metal seat tightness in the event ofO-ring or Teflon seal (UM DA) failure.Lapping O-Ring SeatingSurfacesRefer to Figure 10 and assemble the O-ring retainerto the disc holder (8) (D through J orifice) or disc (6) (Kthrough U orifice) using the retainer lock screw(s) asfollows:1. Apply 3A lapping compound to the retainerseatingsurface.2. Place the retainer on the nozzle seat (see Figure 26)and lap the retainer to the nozzle (2).3. Once uniform contact is established, clean the nozzle(2) and O-ring retainer.4. Repeat the procedure with 1000-grit compound.5. Remove the retainer lock screw(s) and O‐ringretainer, and thoroughly clean the O-ring retainer,retainer lock screws, and disc holder (8) or disc (6).Nozzle laps (see Figure 27) must be re-machined torecondition the lapping surfaces. Place the nozzle lap ina lathe between centers (see Figure 30). The surfacesmarked A and B must be running concentrically.One lapping surface is 90º and the other is 85º. Theangle of each surface is marked on the lap. Machinesurfaces C and D by taking light cuts at the proper angleuntil the lapping surfaces are reconditioned.A C D BLathe CenterFigure 29: Lapping Pattern9085°Lathe CenterFigure 30: Nozzle Lap in a Lathe34 | Dresser Consolidated ®
XI. Maintenance (Contd.)Re-Machining Nozzle Seatsand Bores1. Remove the nozzle (2) from the valve to beremachined. If it cannot be removed from the base(1), re-machine it inside the base.2. Set-up the lathe and nozzle (2) as follows:• Grip the nozzle in a four-jaw independent chuck (orcollet, if appropriate) using a piece of soft materialsuch as copper or fiber between the jaws and thenozzle (see Figure 31, A).• True-up the nozzle so that the surfaces marked B,C, and D run true within .001” (.025 mm) on thetotal indicator reading (see Figure 31).CBAChuck JawNozzleFigure 31: Nozzle Positioned in a JawD• Make light cuts across surface A at 45º untilthe damaged areas are removed. Turn to thesmoothest possible finish.• Cut back the outside surface at M until dimensionJ is obtained. Re-machine radius B.The nozzle is now ready for lapping.• Discard the nozzle when the minimum dimensionD (see Figure 19 and Table 1) is reached.Re-Machining the Disc SeatMachine the standard disc seating surface (see Figure28) as follows:1. Grip the disc (6) in a four-jaw independent chuck (orcollet, if appropriate), using a piece of soft materialsuch as copper or fiber between the jaws and thedisc (see Figure 32, A).2. True-up the disc (6) so that the surface marked Band C run true within .001" (0.025 mm) on the totalindicator reading (see Figure 32).3. Make light cuts across the seating surface L untildamaged areas are removed. Turn to the smoothestpossible finish.The disc (6) is now ready for lapping.• Discard the disc if the minimum dimension Nor T (Figure 16 and Table 3) is reached. Do notreestablish surface C as (see Figure 32).Chuck Jaw3. Re-machine the metal-to-metal seat (see Figure 19and Table 1) as follows:• Make light cuts across the surface L at 5º untilthe damaged areas are removed. Turn to thesmoothest possible finish.• Cut back the outside surface at G until dimensionN is obtained. The surface at G is common to allnozzles except the D-1. Omit this step on the D-1orifice nozzles.• Re-machine diameter H, until dimension E isobtained. Reestablish angle P.The nozzle is now ready for lapping.• Discard the nozzle when the minimum dimensionD (see Figure 19 and Table 1) is reached.4. Re-machine the O-ring seat seal (see Figure 19 andTable 1) as follows:ATTENTION!!90°CLDiscFigure 32: Standard Disc Seating SurfaceDo not machine a Thermodisc, O-ring Seat disc, orSoft-seat (UM DA) disc.BA1900 Series Safety Valve (July/2010) | 35
Page 4 and 5: Table of ContentsSection Subject Pa
Page 6 and 7: I. Product Safety Sign and Label Sy
Page 8 and 9: III. IntroductionThe safety relief
Page 10 and 11: V. (Contd.)V.1.1 Standard Cap Types
Page 12 and 13: V. (Contd.)V.3 V-W Bellows Metal Se
Page 14 and 15: VI. Handling, Storage, and Pre-Inst
Page 16 and 17: VII. Recommended Installation Pract
Page 18: VIII. Disassembly Instructions (Con
Page 21 and 22: X. Parts InspectionNozzle Inspectio
Page 23 and 24: X. Parts Inspection (Contd.)Orifice
Page 25 and 26: X. Parts Inspection (Contd.)AFigure
Page 27 and 28: X. Parts Inspection (Contd.)Orifice
Page 29 and 30: X. Parts Inspection (Contd.)Guide I
Page 31 and 32: XI. MaintenanceGeneral InformationA
Page 33: XI. Maintenance (Contd.)Table 7d: N
Page 37 and 38: XI. Maintenance (Contd.)OrificeSize
Page 39 and 40: XII. ReassemblyGeneral InformationT
Page 41 and 42: XII. Reassembly (Contd.) Use a scre
Page 43 and 44: XII. Reassembly (Contd.)OrificeTabl
Page 45 and 46: XIII. Setting and TestingGeneral In
Page 47 and 48: XIII. Setting and Testing (Contd.)S
Page 49 and 50: XIII. Setting and Testing (Contd.)I
Page 51 and 52: XVI. Conversion of 1900 Series Flan
Page 53 and 54: XVII. Troubleshooting 1900 Series S
Page 55 and 56: XIX. Replacement Parts PlanningBasi
Page 57 and 58: XXI. Recommended Spare Parts for 19
Page 59 and 60: XXI. Manufacturer’s Warranty, Fie
Page 61 and 62: XXV. Optional Glide-Aloy PartsOptio
Page 63 and 64: XXVI. Sales Office LocationsMALAYSI

1900 Series - Maintenance Manual

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