Midland A-718C Maintance Manual
Document Number: A-718C, Revision # 1
7733 Gross Point Road • Skokie, IL 60077 • (847) 677-0333 • Fax (847) 677-0138 • www.midlandmfg.com
Issue Date: March 9, 2017
1" Angle Valves
A-718C Series
Installation, Operation & Maintenance Manual
Page 1 of 36
Table of Contents
1.0 Introduction ................................................................................................................................... 3
1.1 Technical Specifications ............................................................................................................ 3
1.2 Torque Values for Bolts ............................................................................................................. 4
1.3 Valve Perspectives.................................................................................................................... 5
1.4 Pre-Installation Regulations / Requirements.............................................................................. 7
2.0 Valve Installation ........................................................................................................................... 9
2.1 Preliminary Considerations ....................................................................................................... 9
2.2 Installation Procedure ............................................................................................................... 9
3.0 Operating Instructions ................................................................................................................. 12
3.1 Valve Operation Notes and Precautions .................................................................................. 12
4.0 Maintenance Instructions ............................................................................................................ 13
4.1 Prior to Maintenance Tasks Performed ................................................................................... 13
5.0 Valve Disassembly ...................................................................................................................... 14
6.0 Valve Inspection & Replacement of Parts ................................................................................... 20
6.1 Inspection & Replacement Procedure ..................................................................................... 20
6.2 Special Inspection Considerations .......................................................................................... 23
7.0 Cleaning...................................................................................................................................... 24
8.0 Valve Reassembly ...................................................................................................................... 25
9.0 Valve Testing Procedure ............................................................................................................. 35
9.1 Testing Procedure ................................................................................................................... 35
9.2 Post-Test Procedures ............................................................................................................. 35
10.0 Warranty ................................................................................................................................... 36
Doc. #: A-718C, Rev. 1
Page 2 of 36
1.0 Introduction
The A-718C Series 1" angle valves are top loading transfer valves with a unique seat design that permits selfdraining 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.
Successfully used in Chlorine-transfer applications
Self-centering valve seat permits positive shut-off with lower operating torque
Utilized in the top-loading of pressure cars
1.1 Technical Specifications
Figure 1-1 Valve Specifications
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1.2 Torque Values for Bolts
Item #
Description
Material
Torque Value
6
Cap Screws
1/2-13 UNC 2B
Monel
48 ft-lb
CS
38 ft-lb
13
Top Nut
1/2-13 UNC 2B
SS
20 ft-lb
16
Hex Nut
3/8-16 UNC 2A
Monel
22 ft-lb
CS
20 ft-lb
19
Slotted Nut
7/18-20 UNF 2B
Inconel
38 ft-lb
SS
32 ft-lb
Table 1-1 Torque Values for Bolts
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1.3 Valve Perspectives
Item
Qty.
Part Name
1 1 Hand Wheel
2 1 Stem
3 1 Seal Retainer
4 1 Body
5 1 1" Bonnet
6 3 Cap Screw
7 1 Packing Screw w/Insert
8 1 Packing Insert
9 1 Seat Seal-VV
10 1 Packing Ring Assembly
11 2 O-Ring-Stem
12 2 O-Ring-Flange
13 1 Lock Nut
14 4 Stud
15 4 3/8" Split Lock Washer
16 4 Hex Nut
17 1 O-Ring
18 1 Retaining Pin
19 1 Slotted Nut
20 1 Male Packing Adapter
21 3 1/2" Split Lock Washer
22 1 Outlet Flange Gasket
23 1 Instruction Plate
24 1 Wiper
25 1 Washer
26 1 Name Plate
27 1 Retaining Seal Washer
28 1 Packing Spring
29 1 1" Pipe Plug Assembly
30 1 Outlet Flange
31 1 Seat Insert
32 1 Lower Gasket
33 2 O-Ring-Seat Insert
34 2 Drive Screw
35 1 Placard (Not Shown)
Figure 1-2 Isometric View
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Figure 1-3 Side View and Cross-Sectional View with Callouts
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1.4 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. All personnel should be familiar with and follow these
regulations. Nothing in these instructions is intended to conflict with or supersede these regulations. The
information in this document was gathered from knowledgeable sources, but Midland Manufacturing
Corporation makes no representations or guarantees about its accuracy or completeness and assumes no
liability for this information.
Specifications are subject to engineering updates and may change without notice.
1.4.2 Safety Precautions
Midland valves are used in connection with a variety of products, many of which are hazardous materials and
could cause serious injury or damage.
CAUTION: Toxic Hazard. Always use extreme caution and proper equipment when involved with
hazardous materials. To avoid exposure to toxic or hazardous materials, make sure the tank car is
empty and clean, and that the work area is free of hazardous chemicals before removing or
installing any valve.
1.4.3 Precautions for Mounted-Valve Repair
When performing maintenance on an angle valve that is mounted on a railcar, observe the following
precautions.
o Wear protective clothing and equipment suitable for withstanding the materials to which you may
be exposed
o Position yourself on the upwind side of the valve when possible
o Work with a partner who can help you in the event of an emergency
o Follow approved safety precautions for hazardous or toxic materials
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1.4.4 Required Tools
Recommended Wrenches
SAE
Component
Material
Torque [ft-lb (N·m)]
Item #
1/2” Socket/Wrench
Cap Screws
Monel
48 ft-lb (65 N·m)
6
CS
38 ft-lb (52 N·m)
1/2” Socket/Wrench
Top Nut
SS
20 ft-lb (27 N·m)
13
3/8” Socket/Wrench
Hex Nut
Monel
22 ft-lb (30 N·m)
16
CS
20 ft-lb (27 N·m)
7/16” Socket/Wrench
Slotted Nut
Inconel
38 ft-lb (52 N·m)
19
SS
32 ft-lb (43 N·m)
1-1/16” Crow Feet/Wrench
Packing Nut
Inconel
65 ft-lb (88 N·m)
8
Other Tools and Supplies
Screwdrivers
Pipe Wrench
Loctite® (or equivalent adhesive)
Lint-free Cloth
Silicone Grease (or equivalent lubrication)
Emery Paper (400 grit, cut in 1" strips)
Torque Wrench
Wire Brush
Before arriving at the installation site obtain the required tools and supplies prior to performing the procedures
indicated in this guide.
Table 1-2 Required Tools
Table 1-3 Additional Recommended Tools & Supplies
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2.0 Valve Installation
2.1 Preliminary Considerations
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. However, if the valve’s shelf life exceeds six (6) months, retesting or recalibration is
recommended.
2.1.2 Prior to installation, ensure that the valve remains clean and that the gasket-sealing surfaces are not
damaged.
2.2 Installation Procedure
2.2.1 Remove the old valve and then insert a soft rubber plug into the tank opening to prevent debris from entering
the tank during cleaning of the valve-mounting groove and studs on the man-way cover plate.
2.2.2 Wire-brush the 3/4” stud threads of the cover plate until clean.
2.2.3 Remove the gasket in the groove of the cover plate. Avoid scratching the metal in the bottom of the groove.
Discard the used gasket.
2.2.4 Examine the sides of the groove to verify that there are no dents or burrs. Since the valve fits tightly in the
groove, any peening of the groove edges may make it difficult to properly fit the valve’s tongue into the
groove. Install a new 1/8"-thick gasket.
2.2.5 Up to this point, the new valve should have been kept in its original shipping container. Cradle the valve in
your arm and unwind the hand wheel (in the “clockwise” direction) to be in the closed position when it is
bolted onto the cover plate. The valve is in the closed position when the stem is all the way up.
2.2.6 Inspect the tongue by running your finger around the edge of the tongue to be sure it is free of nicks, dents
and burrs. The tolerance on the tongue is plus or minus 0.003", so any irregularity on this surface will make
it difficult to fit the tongue cover plate groove. Similarly, the flat surface of the tongue should be free of
imperfections that could cause a gasket leak when the valve is positioned on the cover plate.
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2.2.7 Take out the rubber plug from the cover plate opening.
Figure 2-1 Maintenance Checkpoints
Packing
Area
Seat
Side-Port
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. The
hand wheel has been purposely weakened to break if excessive force is used.
NOTE: To operate of the valve closed, turn the handle clockwise, the stem will travel all the way
up.
2.2.9 Holding the valve by the bonnet (item 5) lower it slowly onto the studs. Start all four (4) nuts on the studs
while the valve is still held off the cover plate. It may be necessary to lift the valve to make room to insert
nuts adjacent to the outlet flange to allow room to start nuts while the valve is held up. Insert the remaining
nuts and gently move the valve back and forth until the tongue goes down into the groove on the cover
plate. Hand-tighten all four (4) nuts.
2.2.10 Wrench-tighten the nuts a little bit at a time, going alternately from 1 to 3, then 2 to 4. Do not tighten down
too much on one side because this will shift the valve at an angle and may make it impossible to get a tight
gasket seal.
2.2.11 Torque the nuts according to the torque specifications from the gasket manufacture’s recommendations
and to not exceed the torques specified in Section 1.2.
2.2.12 Inspect the valve for leaks according to your company’s procedures for this testing. The primary areas to
check are in the side-port area, the packing gland area, the flange connection between the cover plate, and
the valve and seat. In order to check the seat for leaks on an
installed valve on the tank car, pressure may be applied to the
outlet flange with the valve in the “closed” position. Look for any
pressure decay. Keep in mind that some compensation would
need to be made for pressure changes as temperature changes.
This is recommended in the event that there is no procedure in
Gland
place from your company to test the valve’s seat when installed
on a tank car. When closing the valve, hand-tighten. If it does not
seal, remove the valve for repair per Maintenance Instructions in
Section 4.0.
Area
Insert
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2.2.13 Attached to the bonnet is a tag that indicates operating instructions on one side of the tag and on the reverse
Figure 2-2 Valve Information Tag
Figure 2-3 Important Operating Instructions
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. Fill in the appropriate information on this tag.
2.2.14 A placard with an adhesive backing has been provided with each car set of valves. This gives important
operating instructions. The placard should be placed on the underside of the hinged protective housing
cover for the guidance of the personnel using these angle valves.
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