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Dover MIDLAND A-1402C Series, Installation, Operation & Maintenance Manual, Page: 22 / 29

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Dover MIDLAND A-1402C Series Installation, Operation & Maintenance Manual Download Page 22

 Installation, Operation & Maintenance Manual

22

External-Style Pressure Relief Valve A-1402C Series

5 VALVE ASSEMBLY

For valve assembly, please see valve disassembly instructions. Reassemble in reverse order of those instructions.  

Figure 5-1 Exploded View of Valve 

Summary of Contents for MIDLAND A-1402C Series

Page 1: ...on Maintenance Manual www midland com Part No A 1402C Rev 1 3 Issue Date May 2 2022 Supersedes A 1402C Rev 1 2 Sept 27 2016 External Style Pressure Relief Valve A 1402C Series Installation Operation Maintenance IOM Manual ...

Page 2: ...INSTALLATION 10 2 1 Preliminary Considerations 10 2 2 Procedure 10 2 3 Leak Inspection 12 2 4 Valve Operation Notes and Precautions 12 SECTION 3 VALVE DISASSEMBLY 13 3 1 Procedure 13 SECTION 4 VALVE INSPECTION 16 4 1 Inspection Procedures 17 4 1 1 Top Guide 17 4 1 2 Adjusting Screw Threads 17 4 1 3 O Ring Retainer Grooves 17 4 1 4 Valve Body 17 4 1 5 Plug 18 4 1 6 Sealing Surface Valve Mounting 18...

Page 3: ...and and Gauge Requirements 23 SECTION 7 VALVE PRESSURE TESTING PROCEDURE 24 7 1 Without Rupture Disc Installed 24 SECTION 8 VALVE ADJUSTMENT PROCEDURE 25 8 1 Procedure Without Rupture Disc Installed 26 8 2 Valve Pressure Testing Procedure With Rupture Disc Installed 26 8 3 Post Test Procedure 27 SECTION 9 MAINTENANCE 28 9 1 Prior to Maintenance Tasks Performed 28 9 1 1 Retesting of Valves in Stora...

Page 4: ...s improved to include redundant seals to atmosphere eliminating potential leak paths and further increasing the long life and reliability in Chlorine transportation Corrosion resistant materials provide maximum protection from wet Chlorine Successfully used in Chlorine and AHCL applications Triple seals on all potential leak paths to atmosphere 1 1 TECHNICAL SPECIFICATIONS Figure 1 1 Valve Specifi...

Page 5: ...mum Vapor Tight Pressure PSIG A 14377C ML 375 7070 356 285 A 14227C ML 225 4367 213 171 Valve Model Outer Spring Inner Spring Name Plate Adjusting Screw Part Rupture Disc Part A 14377C ML 15 375 SS 14 13 SS 14 377 ML C 15 112 SS 14 23 TA 375 F A 14227C ML 15 150 MO 14 13 SS 14 227 ML C 15 11 SS 14 23 TA 225 F Table 1 1 Technical Specifications Per Valve Model ...

Page 6: ...Installation Operation Maintenance Manual 6 External Style Pressure Relief Valve A 1402C Series Figure 1 2 Exploded View 1 2 VALVE PERSPECTIVES ...

Page 7: ...op Gasket 10 1 Shaft Seal 11 1 Adjusting Seal 12 1 Seal Retainer 13 1 Inner Spring 14 1 Cap 15 1 Seal Screw 16 4 Stud 17 4 Nut 18 1 Wire Seal 19 1 Retainer 20 1 Seat O Ring 21 1 Plug O Ring 22 1 Flue O Ring 23 1 Rupture Disc 24 1 Flue 25 8 Rupture Disc Flange Bolts 26 1 Rupture Disc Flange 27 1 Purge Valve 28 1 Name Plate 29 1 Protective Cap Chain 30 1 Flange O Ring inner 31 1 Flange O Ring outer ...

Page 8: ...carefully before proceeding 1 3 3 Precautions for Mounted Valve Repair When performing maintenance on a pressure relief valve that is mounted on a railcar observe the following precautions Wear protective clothing and equipment suitable for withstanding the materials to which you may be exposed Position yourself on the upwind side of the valve when possible Work with a partner who can help you in ...

Page 9: ... Hex 3 8 Rupture Disc Flange Bolt 25 25 9 16 1 2 Top Guide Nut 50 17 1 1 2 1 Top Lock Nut 45 8 1 2 1 8 NPT Needle Valve Wrench Tight 27 1 1 16 Flats on Small Valve O ring Retainer 5 8 Mounting stud Nuts 1 1 4 Flats on Large Valve O ring Retainer 3 4 Mounting stud Nuts Table 1 2 Required Tools Other Tools and Supplies Screwdrivers Pipe Wrench Wheel Puller Lint free Cloth Silicone Grease or equivale...

Page 10: ...tuds should not exhibit excessive corrosion 2 2 3 Remove and discard all used gasket material 2 2 4 Using a lint free cloth and appropriate cleaning solvent wipe clean the valve and cover plate sealing surfaces and the mounting stud threads 2 2 5 For tongue and groove mountings examine the sides of the groove Because the valve tongue fits tightly into the groove any peening over of the edges of th...

Page 11: ...he mounting Align the body holes over the studs and lower the valve while positioning the valve tongue in the cover plate groove 2 2 11 Install the nuts and tighten them in 1 3 torque increments in a diagonally alternating sequence to a torque specified by the gasket specified as shown in Figure 2 3 Figure 2 3 Mounting Nut Tightening Sequence CAUTION To prevent Tongue Damage do not install a valve...

Page 12: ... disc setting NOTE Operation of the valve must conform with all applicable TC AAR DOT specifications Parts 173 31 174 67 etc other governmental bodies and the operating instructions of your company The pressure relief valves are spring loaded and are actuated by overpressure in the railcar tank There are no provisions for manual activation of the valve CAUTION Needle Valve Closure For valves equip...

Page 13: ...pture disc flange bolts Item 25 of Figure 1 3 from the valve base Separate the disc flange from the valve base and remove the rupture disc Item 23 inner and outer O rings Items 30 and 31 respectively see Figure 1 3 Figure 3 1 Valve Cap Removal Figure 3 2 Flue and Protective Cap CAUTION Spring loaded Assembly During valve spring disassembly the valve contains springs under load DO NOT attempt to di...

Page 14: ...the guide Item 7 3 1 13 Lift the stem Item 2 of Figure 1 3 and seal retainer Item 12 straight up and off the shaft and off the plug Item 3 3 1 14 Remove the shaft seal Item 10 of Figure 1 3 from the seal retainer Item 12 3 1 15 Lift or pry up the retainer Item 19 of Figure 1 3 It will likely lift off with the valve plug Item 3 as a single unit 3 1 16 Remove the plug from the retainer CAUTION Ruptu...

Page 15: ... two 2 O Rings Items 20 and 21 respectively see Figure 1 3 from the retainer using only a non scratching tool 3 1 18 Unscrew and remove the needle valve Item 27 of Figure 1 3 from the valve body Figure 3 7 Retainer Valve Stem O Rings and Plug Figure 3 8 Retainer with O Ring ...

Page 16: ...ent can be properly evaluated for damage or cracks only with the use of specialized techniques such as dye penetration or magnetic particle testing according to a qualified procedure by certified trained personnel Such testing is indicated within this document where mandatory Additionally specific inspections must be performed during and after reassembly of the valve to ensure proper and reliable ...

Page 17: ...The grooves Figure 4 2 must be free of gouge marks corrosion pits and rust Since the O rings must seal against these surfaces any irregularities can cause the valve to leak Clean the groove by sanding it lightly with emery paper 400 grit If this does not effectively clean the groove replace this part 4 1 4 Valve Body 4 1 4 1 The sealing surfaces are the crown of the seat and rupture disc sealing s...

Page 18: ...mounting plate on the railcar Figure 4 5 Machining of this surface is permitted A good seating surface is necessary to ensure there are no leaks in this area NOTE Repair work is limited to cleaning and polishing See Paragraph A4 11 1 of the Tank Car Specifications NOTE Please refer to paragraph A4 11 2 of the Tank Car Specifications and consult Appendix E for dimensions and applicable tolerances N...

Page 19: ...nds look for dents or gouged surfaces on the inside of the top guide Repair the damage to allow free movement of the spring guide WARNING Valve Sticking If the spring guide binds in the top guide bore the valve may stick in the open position or be prevented from opening Always ensure free travel of the spring guide before reassembling the valve WARNING Valve Spring Failure Defects in coil springs ...

Page 20: ...es radial tool marks nicks burrs or corrosion can be present in the groove or the disc will fail to maintain a pressure tight seal If dents pits or gouges are observed do not attempt to remove them by machining Discard the flange and obtain a new one 4 1 10 2 Similarly on the raised surface on the underside of the valve body flange also in contact with the rupture disc must be completely free of i...

Page 21: ...eaning inspection and specialized testing performed by agencies other than the repair facility are the responsibility of the repair facility Where numerical tolerances cannot be provided the disposition of the internal integrity and surface quality of parts is under the jurisdiction of the repair facility and dependent on its experience and judgment CAUTION O Ring Degradation O rings develop micro...

Page 22: ...enance Manual 22 External Style Pressure Relief Valve A 1402C Series 5 VALVE ASSEMBLY For valve assembly please see valve disassembly instructions Reassemble in reverse order of those instructions Figure 5 1 Exploded View of Valve ...

Page 23: ... gauge must meet the requirements of D4 5 Test Gauge Standards and must be date tagged CAUTION Safety Protection Wear appropriate safety glasses or face shield and protective clothing when conducting this procedure Valve testing involves high velocity air and water flow that can cause injury CAUTION NOTE A popping pressure is not specified It is only necessary to ascertain the STD pressure as pres...

Page 24: ...ressure until the valve STD pressure is reached The initial opening of the valve may be slightly high and not indicative of the actual STD pressure because the O ring may have been partially stuck to the valve seat 7 1 8 Reduce the air pressure until leakage stops and then reduce pressure to less than one half of the STD pressure Then slowly increase the pressure 7 1 9 Observe the STD pressure and...

Page 25: ...lief Valve A 1402C Series 8 VALVE ADJUSTMENT PROCEDURE If your company has an approved test procedure follow it If it does not these procedures provide essential guidelines in regards to pressure testing Figure 8 1 Valve Components ...

Page 26: ...nt for the midpoint in the STD pressure tolerance range 8 1 7 Retest the valve 8 1 8 If the test results are erratic troubleshooting is more complex Consult your supervising engineer or a Midland representative 8 1 9 When the test results are acceptable tighten the top nut to a torque of 45 3 ft lbs 8 2 VALVE PRESSURE TESTING PROCEDURE WITH RUPTURE DISC INSTALLED 8 2 1 Re install the rupture disc ...

Page 27: ...light to detect defects Also look at the radial seating surface of the disc for creases or small bumps that could be leak paths Since the disc is the most fragile part of the assembly imperfections in any of the parts may be most easily seen in the disc Also inspect the disc flange and mating surface on the underside of the valve body for any imperfections 8 2 9 If there are any imperfections in t...

Page 28: ...actory of a like quantity of product 2 refunding to purchaser money paid to Midland for its product or 3 issuance of written authorization for the Purchaser to repair or replace at costs comparable to Midland s normal manufacturing costs those parts proven defective provided that Purchaser has given to Midland immediate notice upon discovery of such defect Merchandise claimed to be defective shall...

Page 29: ...7733 Gross Point Road Skokie IL 60077 Tel 847 677 0333 Fax 847 677 0138 www midlandmfg com ...

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