Midland A-718C Series Installation, Operation & Maintenance Manual
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Midland A-718C Series Installation, Operation & Maintenance Manual

Midland A-718C Series Installation, Operation & Maintenance Manual

1" angle valves
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Document Number: A-718C, Revision # 1
Issue Date: March 9, 2017
Page 1 of 36
1" Angle Valves
A-718C Series
Installation, Operation & Maintenance Manual
www.midlandmfg.com
7733 Gross Point Road • Skokie, IL 60077 • (847) 677-0333 • Fax (847) 677-0138 •

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Summary of Contents for Midland A-718C Series

  • Page 1 Document Number: A-718C, Revision # 1 Issue Date: March 9, 2017 Page 1 of 36 1" Angle Valves A-718C Series Installation, Operation & Maintenance Manual www.midlandmfg.com 7733 Gross Point Road • Skokie, IL 60077 • (847) 677-0333 • Fax (847) 677-0138 •...

  • Page 2: Table Of Contents

    Table of Contents Introduction ........................... 3 Technical Specifications ......................3 Torque Values for Bolts ......................4 Valve Perspectives........................5 Pre-Installation Regulations / Requirements................7 Valve Installation ........................... 9 Preliminary Considerations ....................... 9 Installation Procedure ....................... 9 Operating Instructions ......................... 12 Valve Operation Notes and Precautions ..................

  • Page 3: Introduction

    Introduction The A-718C Series 1" angle valves are top loading transfer valves with a unique seat design that permits self- draining and ease of maintenance and repair. The energized and adjustable stem packing and soft, self-centering valve seat eliminates potential leak paths and further increasing the long life and reliability in Chlorine transportation.

  • Page 4: Torque Values For Bolts

    Torque Values for Bolts Item # Description Material Torque Value Monel 48 ft-lb Cap Screws 1/2-13 UNC 2B 38 ft-lb 20 ft-lb Top Nut 1/2-13 UNC 2B Monel 22 ft-lb Hex Nut 3/8-16 UNC 2A 20 ft-lb Inconel 38 ft-lb Slotted Nut 7/18-20 UNF 2B 32 ft-lb...

  • Page 5: Valve Perspectives

    Valve Perspectives Item Qty. Part Name Hand Wheel Stem Seal Retainer Body 1" Bonnet Cap Screw Packing Screw w/Insert Packing Insert Seat Seal-VV Packing Ring Assembly O-Ring-Stem O-Ring-Flange Lock Nut Stud 3/8" Split Lock Washer Hex Nut O-Ring Retaining Pin Slotted Nut Male Packing Adapter 1/2"...
  • Page 6 Figure 1-3 Side View and Cross-Sectional View with Callouts Doc. #: A-718C, Rev. 1 Page 6 of 36...

  • Page 7: Pre-Installation Regulations / Requirements

    1.4.1 Regulations Midland Top Transfer, Angle Valves are used in contact with a variety of products, many of which are hazardous materials. 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. Regulations of other governmental bodies must be complied with for stationary and mobile applications.
  • Page 8 1.4.4 Required Tools Before arriving at the installation site obtain the required tools and supplies prior to performing the procedures indicated in this guide. Recommended Wrenches Component Material Torque [ft-lb (N·m)] Item # Monel 48 ft-lb (65 N·m) 1/2” Socket/Wrench Cap Screws 38 ft-lb (52 N·m) 20 ft-lb (27 N·m)

  • Page 9: Valve Installation

    2.1.1 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 10 2.2.7 Take out the rubber plug from the cover plate opening. 2.2.8 The valve should be “closed” with the stem all the way up. Under no circumstances should a “cheater” or handle extension be used to close this valve, as over-tightening will damage the valve’s Teflon seat.
  • Page 11 2.2.13 Attached to the bonnet is a tag that indicates operating instructions on one side of the tag and on the reverse side are blanks to be filled in. The record of the valve’s service experience will be valuable information in evaluating the valve’s performance.

  • Page 12: Operating Instructions

    3.1.1 Bear in mind with the Midland angle valve that it will seal completely with much less torque than a metal- to-metal seated valve. It should close with the same approximate torqueing as with a faucet on a wash basin.

  • Page 13: Maintenance Instructions

    Retesting of Valves in Storage Midland valves are factory set and sealed. If they have been left in their original shipping containers, are undamaged, and are no more than six (6) months old; they may be installed without being retested.

  • Page 14: Valve Disassembly

    5.0 Valve Disassembly 5.1.1 Before valve disassembly, open and close the hand wheel to run the stem (item 2) up and down to ensure that the stem is neither bent nor binding in the threaded part of the bonnet (item 5). Bent stems must be straightened to proceed with the disassembly.
  • Page 15 5.1.3 Remove the outlet flange (item 30). If it is difficult to dislodge, screw a 1" threaded nipple about 10" long into the port. Move it back and forth gently to loosen the flange and work it off the valve body (item 4). Figure 5-4 Remove Outlet Flange 5.1.4 Loosen the packing screw (item 7).
  • Page 16 5.1.6 Rest the end portion of the stem on wood block leveled with body. Make sure there is only 3" between the body and the wood block. Drift out retaining pin using a standard 1/8" diameter drift. Then unscrew the retainer slotted nut, remove the retainer assembly, retainer O-ring and retainer seal washer.
  • Page 17 5.1.7.1 At this point, remove the seat insert (item 31) from the body (item 4). The seat insert will be held in place by pressure exerted by the two (2) O-rings (item 33). One possible option to assist in the removal of the seat insert is by placing a circular piece of hardwood or plastic on top of the seat insert on the inside of the body through the outlet hole.
  • Page 18 (item 20) , wave spring (item 28) and the two (2) stem O-rings in the body (item 11). The hook-shaped tool can be obtained from Midland (P/N: 712-27-CS). This tool should also be used to remove the stem O-rings (item 11), the outlet O-rings (item 12) and insert O-rings (item 33).
  • Page 19 (approximately 1/16"). Run your fingernail around the crown to be sure it is free of any nicks, scratches or pits. Also, any chatter or tool marks on the seat crown should removed. The overall height of the crown should not be less than 7/32". If the tongue needs to be re-dressed, the tongue’s dimensions are 4.745 ± 0.005”...

  • Page 20: Valve Inspection & Replacement Of Parts

    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 21 6.1.2 Stem (item 2). Roll the stem in “V” blocks or on a flat surface. It will be apparent if the stem is bowed. If straightening is required, do not grip or deflect it on the ground surface of the packing zone, in the Acme thread zone, in the 1/16"-20 thread area and below, where deformation of the metal would foul the threads or damage stem straightness.
  • Page 22 Replace with a new seal. This part is made of a special blend of Teflon ® other materials to provide high strength and resistance to cold flow and is not commercially available except from Midland. Figure 6-8 Seat Seal Doc. #: A-718C, Rev. 1...

  • Page 23: Special Inspection Considerations

    Special Inspection Considerations Previous 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. Facilities performing recommended dye-penetration and magnetic-particle testing must carry out such testing according to a qualified procedure conducted by certified trained personnel.

  • Page 24: Cleaning

    7.0 Cleaning NOTE: In preparation for reassembly, all metallic parts should be cleaned. Do not use solvents or grease lubricants that are incompatible with the products in the tank. For example, a petroleum-based grease may cause a chemical reaction when it comes in contact with chlorine. Contact your supervising engineer for suitable cleaning and lubricating material recommendations.

  • Page 25: Valve Reassembly

    8.0 Valve Reassembly 8.1.1 Place the bonnet on the body to ensure an accurate fit. Ensure that the body and bonnet flanges mate with no space in-between. Then take the bonnet off the body. Lightly grease the inside threads, the bore and the bottom flange face of the bonnet.
  • Page 26 8.1.3 If the packing screw and white PTFE wiper (item 24) are in good condition, apply a light film of grease on the inside and outside surfaces of the packing screw. Figure 8-5 Inspect Packing Screw and Wiper Figure 8-6 Grease Packing Screw 8.1.4 Place packing screw (item 8) into the bonnet yoke.
  • Page 27 8.1.6 Assemble five (5) Teflon V-rings (item 11) in a stack and apply grease to the inside and outside of the ® packing. Figure 8-10 Lubricate Rings 8.1.7 Lubricate interior of the body neck. Insert packing spring into the neck of the body as shown. Figure 8-11 Lubricate Body Neck Figure 8-12 Insert Packing Spring 8.1.8...
  • Page 28 8.1.9 Apply grease to the two (2) O-ring grooves recessed in the top of the body. Grease both O-rings. It should be easier to position the top O-ring, then install the other one into the lower groove. Be sure both O-rings are properly installed in the grooves.
  • Page 29 8.1.11 Grease the top part of the body flange and put the bonnet assembly on it, inserting the valve stem through the two installed O-rings of the body. Make sure the bonnet arms are in-line with the triangular outlet of the valve body as shown below.
  • Page 30 8.1.13 Put the hand wheel (item 1) on the stem and run it up and down to be sure the stem moves freely. Figure 8-20 Place Hand Wheel on Stem 8.1.14 Tighten the packing screw to 30 ± 3 ft-lb (40 ± 4 N·m) to seat the Teflon packing rings.
  • Page 31 8.1.16 Grease the cavities in the base of the body, the lower gasket (item 32) and insert gasket. Figure 8-23 Grease Body Base Figure 8-24 Install Lower Gasket 8.1.17 Grease the exterior surface of the seat insert and insert it into the body by pushing it down with the palm of your hang and slowly rotating it.
  • Page 32 8.1.18 Rotate the stem until 7/16"-20 threaded area is well below tongue on the seat insert. Lightly grease the 7/16"-20 threads. Insert retainer seal washer, O-ring and retainer assembly through the bottom of the stem and secure the seat seal in place with retaining nut. Once nut is tightly secured, insert retaining pin to prevent retainer assembly and nut from backing out.
  • Page 33 8.1.21 Press the outlet flange into the side port of the body. Install lock washers and bolts; tighten bolts to 45 ft-lb (61 N·m). Figure 8-33 Install Outlet Flange Figure 8-34 Install Washers/Bolts Figure 8-35 Tighten Bolts 8.1.22 Assemble the instruction plate (item 23), hand wheel washer rounded edge facing upwards (item 25) and hand wheel nut (item 13) on the stem.
  • Page 34 8.1.23 Install the outlet pipe plug (item 29) in the outlet flange. Figure 8-38 Install Pipe Plug 8.1.24 Attach the chain to the body. Figure 8-39 Attach Chain to Body Figure 8-40 Secure Chain to Body Doc. #: A-718C, Rev. 1 Page 34 of 36...

  • Page 35: Valve Testing Procedure

    9.0 Valve Testing 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. 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.

  • Page 36: Warranty

    FOR ANY PARTICULAR PURPOSE OR USE. Midland’s obligation under this warranty is strictly limited, at its option, to 1) repair or replacement at its factory 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...

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