NIBCO Bronze Gate Valves User Manual

NIBCO INC.

WORLD HEADQUARTERS

1516 MIDDLEBURY ST.

ELKHART, IN 46516-4740

USA

PHONE: [phone]

FAX: [phone]

WEB: www.nibco.com

INSTALLATION, OPERATION & MAINTENANCE INSTRUCTIONS

Review Date: 01/18/2012

Original Date: NA

Installation and Maintenance Guidelines for

NIBCO

®

Bronze Gate Valves

1/4” to 3” Class 125, 150 and 300

Figure Numbers

T-111-113
S-111-113
T-134-136
S-134-136

T-131
T-133
T-135

T-174-A

T-176-A
T-174-SS
T-176-SS

CAUTION: Only qualified personnel should undertake the procedures outlined in this document.
NIBCO INC., its agents, representatives and employees assumes no liability for the use of these
procedures. These procedures are offered as suggestions only.

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1.0 GENERAL INFORMATION

1.1 SCOPE

These instructions are furnished for use in the installation, operation and maintenance of
NIBCO 1/4” to 3” Class 125, 150 and 300 bronze gate valves, with screwed in or union
bonnet, rising stem or non-rising stem, and having handwheel operation.

1.2 GENERAL DATA

A. MANUFACTURER

NIBCO INC.
1516 Middlebury Street
Elkhart, IN 46516
Phone: [phone]

B. FIGURE NUMBERS AND DESCRIPTIONS

Figure
Number Description
T111 Class 125 threaded end, rising stem, screw in bonnet
S111 Class 125 solder end, rising stem, screw in bonnet
T113 Class 125 threaded end, non-rising stem, screw in bonnet
S113 Class 125 solder end, non-rising stem, screw in bonnet
T131 Class 150 threaded end, rising stem, screw in bonnet
T134 Class 150 threaded end, rising stem, union bonnet
S134 Class 150 solder end, rising stem, union bonnet
T135 Class 150 threaded end, rising stem, union bonnet, split wedge
T136 Class 150 threaded end, non-rising stem, union bonnet
S136 Class 150 solder end, non-rising stem, union bonnet
T174A Class 300 threaded end, rising stem, union bonnet, Ni-Alloy

wedge

T176A Class 300 threaded end, non-rising stem, union bonnet, Ni-Alloy

wedge

T174SS Class 300 threaded end, rising stem, stainless steel seat rings,

union bonnet

T176SS Class 300 threaded end, non-rising stem, stainless steel seat

rings, union bonnet

All end preparations of valves meet American National Pipe Thread (N.P.T.)
requirements. All solder end valves meet the requirements of ANSI Standard
B16.22.

C. IDENTIFICATION PLATES

An aluminum identification plate is attached beneath the handwheel nut. This
identification plate gives the figure number of the valve, some general information
about the trim and location of NIBCO’s corporate offices.

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When more detailed information is required, the NIBCO 5-100 catalog should be
referred to using the valve figure number as the guide.

D. SERVICE

When installing valves for service in corrosive media, the NIBCO Chemical
Resistance Guide may be consulted for specific data or contact can be made
with NIBCO Technical Services. It is, however, the obligation of the user to make
the ultimate decision of fitness for use.

E. PRESSURE TEMPERATURE RATINGS

Pressure and temperature ratings may be found in the Engineering section of the
latest printing of NIBCO catalog 5-100. This information is taken from applicable
ANSI Standards.

F. CODES & REGULATIONS

A valve used under the jurisdiction of the ASME Boiler and Pressure Vessel
Code, the ANSI code for pressure piping, government or other regulations, is
subject to any limitation of that code or regulation and to the applicable ANSI
Standard.

G. PRODUCTION TEST PROCEDURES

Valves are pneumatically shell tested and seat tested at a pressure of 80 psi in
accordance with Federal Specifications and MSS SP-80 Manufacturers

Standardization Society Requirements.
H. PRINCIPAL DIMENSIONS
Principal dimensions of the valve are specified in the appropriate catalog.

1.3 DETAILED DESCRIPTION

The gate valve listed above and covered in these instructions are bronze valves made of
ASTM B62 material for Class 125 and 150 valves and from ASTM B61 material for
Class 300 valves. Generally, there may be Class 200 valves also listed, however,
NIBCO has optioned not to provide these valves but rather give a Class 300 valve in lieu
of the Class 200.

The valves are operated with the handwheel and are used to start or stop the flow of
fluids in piping systems. Clockwise rotation of the handwheel closes the valve.

The body and bonnet are held together by threads of the male and female type; male
threads being on the bonnet section and female threads being within the body. There
are no gaskets between the body and bonnet to affect seals. This is strictly a metal-to­metal seal as required by standards. This general arrangement is used on the Class 125
and is also used on the Class 150 gate valves.

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For the union bonnet arrangement the body has male threads, the bonnet has no
threads at all; however, a threaded union nut is placed over the bonnet to fasten it to the
body. The seal between the body and bonnet is also metal-to-metal without a gasket.

Flow through the valve is stopped by forcing the wedge down between the seats of the
body. The wedge is a solid type and is guided through its entire travel by guides in the
body.

The head of the stem on the rising stem version fits into a T-slot in the top of the wedge
to allow sufficient wedge movement for effective seating with the seats of the body. On
the non-rising stem version, the wedge has internal female threads and the stem has
male threads which are left handed to cause the wedge to close when the handwheel is
turned in a clockwise direction and the wedge to rise when it is turned in a
counterclockwise direction.

All valves have back seats between the shoulder of the stem and the valve bonnet. This
is a requirement of standards so that the valve may be repacked while the valve is under
full pressure. CAUTION: This is dangerous and could result in serious injury. It is not
recommended by NIBCO. In addition, standards, organizations, and governing societies
today do not encourage valves to be repacked while the valve is transmitting a fluid at
full pressure and/or temperature.

The stuffing box is formed by the annular space between the stem and the bonnet and is
filled with non-asbestos packing. The packing is compressed in the stuffing box by a
gland bushing and the packing nut drawn down against the packing by turning the nut
clockwise.

2.0 INSTALLATION

2.1 PRELIMINARY INFORMATION

The gate valves should preferably be installed with the stem pointed vertically upward.
However, it is normally acceptable to have the valve stem pointed in a horizontal position
either in vertical or horizontal piping. Although a gate valve will function satisfactorily in
an inverted position it is not generally recommended because it allows fluids to become
trapped in the bonnet cavity resulting in contamination and inability to fully drain the
system.

Valves are shipped in the closed position to prevent damage to the seating surfaces.
There is no internal blocking used for shipment. All NIBCO valves are shipped in
cardboard boxes for protection against exterior damage and accumulation of dust or dirt
on the delicate seating surfaces. The boxes are not waterproof and, therefore, require
that they be protected from the weather.

2.2 HANDLING AND INSTALLATION

Each valve should be handled very carefully and not dropped or thrown into a dirty
environment before it is assembled into the system. Under no circumstances should the
valve be installed into the line by wrenching through the valve body, this means that

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when a valve is being threaded onto a pipe, the wrench should be on the end where the
joint is being made.

It is very important to make certain that the threads of the pipe are clean at all times and
machined properly. When improperly tapered pipe is screwed into the female valve
threads the pipe can be screwed so deep that it can ruin the seats of the valve. Care
should also be used to assure that the valve is not over tightened because the steel pipe
is much stronger than the bronze material therefore the bronze will distort and cause
valve malfunction or leakage at the joint. When screwing the valve onto the pipe, the
wedge should remain in the closed position.

On solder end type valves it is necessary to make sure that the valve wedge is in the
open position while it is being heated for soldering into the line. The major caution here
is that the valve not be overheated and that the proper amount of solder is used so that it
does not flow into the valve rendering it inoperable.

Attached to this report in the Appendix are proper instructions for soldering, brazing, and
threading type installation of valves.

In the event that it is necessary to remove the bonnet before the valve is put into a line
either for brazing, soldering or threading in, it is always essential that the bonnet be
removed with great care. It is necessary that a chain wrench rather than a pipe wrench
be used to loosen the bonnet union nut. If at all possible, it is more desirable to use a
socket wrench to remove the nut. The union nut, body and bonnet should all be marked
so they can be returned to the same position as originally assembled. After the nut has
been carefully removed or in the case of a screw in bonnet, the bonnet has been broken
loose, (which may require slight impact), it is then necessary to open the wedge
approximately to its halfway position before removing the bonnet assembly from the
valve body. After doing this, it is important that a mark be put on the wedge and the body
so that it is put back in the same position in the valve body, as it was taken out. lt is vital
that no nicks or scars be put on the body or bonnet sealing areas, as this will create a
leak path. It is extremely important to make sure that the wedge does not fall and hit any
hard surface as it is being removed from the valve. Any mark or dent may cause leakage
on the delicate seating surfaces after the valve is reassembled.

The valve body should then be installed into the pipe system using the appropriate
procedures as outlined in valve installation for soldered, brazed or threaded ends. When
reassembling the valve the wedge should be again positioned at the approximate
halfway open position. Care should also be exercised so the wedge guides are properly
engaged in the body guides.

A slight amount of lubricant equivalent to about 10 weight oil should be put on the
bonnet joint sealing surface of the body and the bonnet and on the top side of the bonnet
when union nut joints are used. This gives lubrication to the joint so good tightening
pressures can be applied. The chain wrench or socket wrench should be used to tighten
the bonnet. Stop the union nut approximately at the same place where it was when the
valve was disassembled or possibly slightly past that mark. Remember any nick on the
surfaces on the bonnet sealing area assures leakage.

After the valve has been installed, the valve should be tested to make sure that it opens
and closes easily and that the bonnet joints or pipe joints are not leaking.

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3.0 OPERATION

Gate valves should never be used for throttling purposes. They should be fully opened
or fully closed. If the valves were only slightly opened, wire drawing and erosion of the
wedge and seats would result. It is not recommended valves be tightly back-seated as
line contamination over a long period of time may lock up the valve causing problems
when the valve has to be closed..

4.0 TROUBLESHOOTING

4.1 LEAKAGE THROUGH THE BONNET JOINT

If the bonnet joint leaks, the valve should be isolated and depressurized. The bonnet
should be removed according to instructions in Section 2. The seating surfaces of the
bonnet and body should be closely inspected. If there is any scratch or mark on these
surfaces then it is necessary that a flat surface sanding plate of 400 grit be used on the
body to remove all the scratches. After the scratches are removed, blueing should be
applied to a flat plate and put onto the bonnet surface, if there are no high spots on the
bonnet surface, then it is prepared for reassembly. On the bonnet surface, if there are
scratches or nicks that are evident it is necessary that it be indicated in a lathe and a
very slight cut taken off of the bonnet sealing surface at an angle of approximately 2-1/2”
tapered outward with a very fine 32 RMS finish. The two body bonnet surfaces then can
be reassembled using procedures in Section 2.

4.2 LEAKAGE THROUGH THE VALVE SEAT

Leakage across the valve seat most of the time is generally due to foreign matter lodged
in the seat. Occasionally, such foreign material can be washed away by allowing flow
through the valve. At times the leakage may be overcome by tightening the valve further.
If the leakage persists, disassemble the valve and examine the seat surface on the
wedge and the seat surfaces within the body.

Minor scratches can be corrected by polishing the wedge face, but generally on bronze
valves if there are deep scratches in the body seats, the valve should be replaced
because it is extremely difficult to repair the surfaces in the small interior of the valve
body. If the wedge does have scratches it is generally acceptable to take a piece of 400
grit sandpaper, lay it upon a flat piece of glass, and slightly polish the surface of the
wedge. This will remove some of the scratches and possibly reduce the amount of
leakage.

4.3 LEAKAGE THROUGH THE STUFFING BOX

Leakage through the stuffing box packing may be stopped by tightening the packing nut.
Do not over tighten as excessive tightening may cause difficult operation of the valve
and could cause damage to the stem or packing nut.

If the gland has run out of travel, isolate and depressurize the valve for repacking or the
addition of more packing. Repacking of valves under pressure is not a recommended
practice. This is dangerous and could result in serious injury even if the valve appears to
be back-seated.

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Foreign matter may have accumulated on the back seat, or by accident the stem could
be knocked off the back seat position thereby allowing dangerous fluids to injure
maintenance personnel.

Remove the handwheel packing nut and gland to remove the old packing. After the
packing is removed, discard and do not try to put it back once it has been removed.
Clean the stem and examine it for damage. On very small valves the packing is
sometimes rope and is sometimes spiral wound around the stem and pushed into the
stuffing box. Install the new packing which may be one piece or split rings. If it is split
ring rope packing install one ring at a time with the diagonal cut in each ring being
staggered 90° away from the cut in the ring below. Each ring should be firmly
compressed in the stuffing box after it is placed in position before the next ring is added.
Install the gland bushing and packing nut and tighten down. The packing nut should be
tightened only enough to prevent leakage. Pressurize the valve and check the packing
for leakage. Tighten as required.

5.0 MAINTENANCE

5.1 TOOLS AND EQUIPMENT

Standard wrenches and tools are suitable for servicing valves as follows:
A. For removing bonnet of the union type – a chain wrench is normally used or the

appropriate socket that will fit the bonnet union nut. For screw in type bonnets –
generally a socket wrench or open end wrench may be used if extreme caution is
used. Pipe wrenches on union nuts or screw in bonnets have a definite crushing
action which will deform the component and are not recommended.

B. A standard packing tool can be used and/or a blunt hook is generally used to remove

packing rings. A screwdriver can be used to raise the packing gland if it is in the fully
down position and generally open end wrenches are used to tighten the packing nut.

C. Combination oil stone, flat plate glass will be used and fine 400 grit sandpaper to

polish the wedge. Flat plates to check high spots on flat surfaces such as bonnet,
seal surface and wedge in conjunction with machinist blueing.

6.0 SPARE PARTS

Normal spare parts to be maintained on hand are listed on the NIBCO spare parts list
(see Appendix).

If the bonnet or body is damaged, it is normally less expensive to remove the entire
valve from the line and install a new one.

When placing an order for spare parts it is necessary to give the size, the valve figure
number found on the aluminum identification plate and also the serial letter which is cast
into the valve body on its side. This will be an alphabetical letter A, B, C, D, etc. It is vital
to give the serial letter because over a period of time the valve designs have had
modifications which could render the parts useless if they are of a different letter series.

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7.0 MAJOR REPAIRS

For other repairs or replacements not covered in the above description, contact the
Technical Services Department of NIBCO INC. for special instructions. Always give the
figure number and size shown on the identification plate affixed to the valve along with
the general serial letter.

For any technical enquiries please call NIBCO Technical Services.

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