Midland A-1076 Series Installation, Operation & Maintenance Manual
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Midland A-1076 Series Installation, Operation & Maintenance Manual

Midland A-1076 Series Installation, Operation & Maintenance Manual

Internal-style pressure relief valve
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Internal-Style Pressure Relief Valve
A-1076/A-1281 Series
Installation, Operation & Maintenance (IOM) Manual
P/N: A-1076/A-1281, Rev. 2.1
Issue Date: April 10, 2018
Supersedes: A-1076/A-1281, Rev. 2

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  • Page 1 P/N: A-1076/A-1281, Rev. 2.1 Issue Date: April 10, 2018 Supersedes: A-1076/A-1281, Rev. 2 Internal-Style Pressure Relief Valve A-1076/A-1281 Series Installation, Operation & Maintenance (IOM) Manual Manual content is subject to change. Visit www.midlandmfg.com for latest manual revision and revision history.

  • Page 2: Table Of Contents

    Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. Table of Contents " Regulations and Safety Requirements .................... 3 Regulations ..........................3 Safety Warnings and Precautions ................... 3 Introduction ............................. 6 Valve Details ........................... 6 Valve Installation ..........................

  • Page 3: Regulations And Safety Requirements

    1 Regulations and Safety Requirements 1.1 Regulations Midland internal-style pressure relief valves are used in contact with a variety of products, many of which are hazardous materials and could cause serious injury or damage if mishandled. The acceptance and transportation of products are regulated by the DOT and AAR in the U.S.A., and in Canada by CTC and Transport Canada.
  • Page 4 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. CAUTION: Valve Leakage. Improper valve-tongue seating in the flange groove, loose nuts and damaged gaskets may result in leaks at the valve-mounting joint. CAUTION CAUTION: Incorrect Spring Setting. Never adjust the spring compression of a valve while it is mounted on the vessel cover plate or incorrect settings may result.
  • Page 5 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. CAUTION: Valve Sticking. If the spring guide binds in the guide tube (nozzle), 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.

  • Page 6: Introduction

    • Available with optional flues 2.1 Valve Details VALVE MODEL NET FLOW AREA (IN FLOW RATE (SCFM) VALVE PRESSURE SETTING (PSIG) A-1076 Series 0.687 A-1281 Series 0.687 3332 280.5 Table 2-1 Valve Specifications Figure 2-1 Valve with Protective Flue & Cap Assembly A-1076/A-1281, Rev.
  • Page 7 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. Figure 2-2 Valve with Protective Flue & Cap Assembly (Top View) Figure 2-3 Valve with Protective Flue & Cap Assembly (Isometric View) A-1076/A-1281, Rev. 2.1 Page 7 of 40...
  • Page 8 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. Figure 2-5 Valve without Flue/Cap Assembly (Top View) Figure 2-6 Valve without Flue/Cap Assembly (Isometric View) A-1076/A-1281, Rev. 2.1 Page 8 of 40...
  • Page 9 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. ITEM QTY. PART NAME MATERIAL A-1076 PART NO. A-1281 PART NO. TOP GUIDE STAINLESS STEEL 10-32-SS 10-32-SS STEM STAINLESS STEEL 10-27-SS 10-27-SS RETAINER STAINLESS STEEL 10-3-SS 10-3-SS VALVE BODY...

  • Page 10: Valve Installation

    3 Valve Installation New valves are tested, adjusted and sealed at Midland. If a new valve has been left in its original packaging, is undamaged and is not more than six (6) months old, it may be installed on a tank car without retesting or recalibration.
  • Page 11 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 3.1.5 For tongue-and-groove mountings, examine the sides of the groove. The valve tongue fits tightly into the groove, any peening-over of the edges of the groove may make it difficult to properly fit the valve tongue into the groove.

  • Page 12: Leak Inspection

    Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 3.1.10 Install the nuts and tighten them in 1/3-torque increments in a diagonally alternating sequence, as shown in Figure 3-2. Consult gasket manufacturer for recommended torque requirements. NOTICE: This is for installation to the car, so the pattern is on the outside bolts.

  • Page 13: Valve Qualification

    Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4 Valve Qualification NOTICE: To ensure best practice and consistency of your qualification procedure, O-rings, gaskets and wire seals should always be replaced. Nuts, washers and studs must be closely inspected before re-use or replaced regularly. NOTICE Valve components such as the top guide, stem, retainer, body and spring must be thoroughly inspected.
  • Page 14 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.1.1 If applicable, remove the cap and 8-inch chain assembly (item 21). Figure 4-1 Remove Wire Seal 4.1.2 Remove the seal wires (item 16) from top-guide standoffs (item 14). Figure 4-2 Remove the Four Nuts 4.1.3 Then, remove the two (2) locknuts (item 15) from the top guide (item 1).
  • Page 15 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.1.5 Remove the rubber bumper washer (item 9) from the retainer (item 3) and the flue gasket (item 17), if applicable. Figure 4-5 Remove Washer 4.1.6 Loosen the top locknut (item 8) with a wrench on the stem (item 2) while holding the retainer in place (item 3) with another wrench.
  • Page 16 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.1.9 Remove the O-rings (items 10 and 11) from the O-ring groove of the retainer (item 3). TIP: Use a non-scratching tool to remove the O-rings. Figure 4-9 Remove O-Rings 4.1.10 Remove wire seal kit (item 16).
  • Page 17 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.1.12 Place the valve into a press having a support block or floorboard to allow pass-through of the valve stem. Figure 4-12 Place Valve in a Press 4.1.13 Using a press yoke having a cutaway as shown, compress the valve spring enough to allow removal of the adjustment nut (item 12) while taking care to support the valve stem.
  • Page 18 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.1.15 Remove the valve from the press, taking care to lift it by the valve stem (item 2). This will prevent the stem from falling out of the valve body. WARNING: Valve/Seat Damage.

  • Page 19: Component Inspection

    Refer to AAR MSRP C-111 [M-1002] Appendix J for requirements of non-destructive testing programs and the responsibilities for their administration. O-Rings, gaskets and wire seals must always be replaced during this step. Midland suggests that nuts, washers and studs be regularly replaced during the qualification process. A-1076/A-1281, Rev. 2.1 Page 19 of 40...
  • Page 20 Visit midlandmfg.com for latest manual revision and revision history. NOTICE: Procedures may not cover all conditions encountered in the field. Therefore, it is the responsibility of the repair agency to obtain approval from Midland for inspection, evaluation, repair and maintenance procedures not covered herein.
  • Page 21 NOTICE: Total valve-stem runout can be checked using a uni-level concentricity fixture and gauge (not supplied by Midland). For this or any other devices used to measure runout, refer to your company’s or to your specific instrument’s IOM for proper use instructions.
  • Page 22 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.2.4 Retainer Inspection Since the O-rings must seal against the retainer surfaces, any irregularities can cause the valve to leak. The O-ring retainer (item 3) grooves must be free of gouge marks, corrosion, pits and rust, if any of these are present, replace this part.
  • Page 23 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.2.6 Spring Inspection The spring (item 5) is a highly stressed part. The exterior surface must be free of pitting and cracks. Magnetic-particle or dye-penetration inspection (performed by certified and trained personnel) can be used to evaluate the exterior surface and ensure that it is free of cracks and corrosion pits.
  • Page 24 An O-ring that fits loosely in the cap, or can only be pushed into the O-ring retainer with difficulty, is quite likely not the correct size. Many of Midland’s O-rings are made on special molds to non-standard sizes and are obtainable only from Midland.

  • Page 25: Valve Reassembly And Recommended Tools

    Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.3 Valve Reassembly and Recommended Tools SAE Wrench Component(s)/Description Item # Torque (ft-lb) 9/16” Top Locknuts and Standoffs 14, 15 15/16” Locknut for Spring Adjustment 15/16”...
  • Page 26 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.3.1 Mount the bumper washer (item 9) onto the retainer (item 3). Figure 4-29 Install Washer 4.3.2 Insert the seat O-ring (item 10) and stem O-ring (item 11) into the retainer (item 3).
  • Page 27 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.3.5 Mate the spring guide tube (item 7) with the body (item 4), if applicable. Figure 4-33 Install Guide Tube 4.3.6 Insert the spring (item 5) into the spring guide (item 7). Figure 4-34 Install Spring 4.3.7 Place the valve into a press having a support block or floorboard to...
  • Page 28 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.3.8 Using a press yoke having a cutaway as shown, compress the valve spring enough to allow application of the follower (item 6) and the adjustment nut (item 12) while taking care to support the valve stem.
  • Page 29 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.3.14 Screw the top locknut (item 8) onto the stem (item 2). Figure 4-39 Install Top Locknut 4.3.15 While holding the retainer (item 3), tighten the top locknut (8) using a torque wrench calibrated to ft-lb.

  • Page 30: Testing Process

    (STD is defined as a continuous discharge in contrast to the start-to-leak pressure, which is defined as the first bubble leak. Vapor-tight is defined as the pressure at whch no bubbles are detected. Midland NOTICE recommends that no bubbles be observed for two (2) minutes at vapor-tight.)
  • Page 31 4.4.3.5 Record the values. NOTICE: If the test results are erratic, troubleshooting is more complex. Consult your supervising engineer or a Midland Manufacturing representative. NOTICE 4.4.3.6 When the test results are acceptable, tighten the bottom locknut (item 13) to torque at 85–95 ft-lb.

  • Page 32: Valve-Setting Adjustment Procedure

    Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.5 Valve-Setting Adjustment Procedure If your company has an approved test procedure, follow it. If it does not, these procedures provide essential guidelines in regard to pressure testing. 4.5.1 Remove the wire seal (item 16) from the spring adjustment nut (item 12), if required.
  • Page 33 STD tolerance range. Refer to Table 4-2 Start-To-Discharge (STD) and Vapor-Tight Pressure (VTP) Settings 4.5.8 If the test results are erratic, troubleshooting is more complex. Consult your supervising engineer or a Midland representative. 4.5.9 When the test results are acceptable, tighten the locknut (item 13) to torque at 85–95 ft-lb.

  • Page 34: Post-Test Procedure

    Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 4.6 Post-Test Procedure 4.6.1 After testing the valve, close the pressure inlet valve to the test chamber and vent the pressure in the test stand. Remove putty and drain water. Then remove the valve from the test fixture. 4.6.2 Wipe or blow away any remaining soap suds and water used in the testing.

  • Page 35: Routine Maintenance

    No regular, periodic maintenance of the mechanical working of this valve is required outside of regular standard qualification. However, Midland recommends that the installed valve be inspected on a regular basis to ensure that the tamper wire and weather cap are in place and that the external visible valve body is free of any foreign materials that could impact its intended operation.
  • Page 36 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 5.1.2 Remove the top guide seal wire (item 16). Figure 5-1 Remove Wire Seal 5.1.3 Then, remove the two (2) top guide nuts (items 15) and store them so they will not be dropped or lost.
  • Page 37 Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 5.1.6 Replace the retainer (item 3). Figure 5-5 Replace Retainer 5.1.7 Insert (2) O-rings (items 10 and 11) into the retainer (item 3). Figure 5-6 Insert O-Rings 5.1.8 Place the retainer (item 3) with the seat O-ring assembly onto the stem (item 2) so that it rests squarely on the valve assembly.
  • Page 38 CAUTION: Do not look directly down into the the valve, debris may discharge upwards. CAUTION NOTICE: If the test results are erratic, troubleshooting is more complex. Consult your surpervising engineer or a Midland Maufacturing representative. NOTICE A-1076/A-1281, Rev. 2.1 Page 38 of 40...

  • Page 39: Emergency Response For Leaking Valve

    Manual content is subject to change. Visit midlandmfg.com for latest manual revision and revision history. 6 Emergency Response for Leaking Valve NOTICE: Emergency Response is the temporary remediation to a valve observed to be emitting product in an unintended manner. It is possible to replace o-rings on an internal style valve installed on a pressurized tank car.
  • Page 40 © Copyright 2017, OPW. Printed in USA. © 2017 Delaware Capital Formation, Inc. All Rights Reserved.

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A-1281 series

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