KSB MIL 21000 User manual

The following instructions should be thoroughly
reviewed and understood prior to installing, operating
or performing maintenance on this equipment.
Throughout the text, safety and/or caution notes will
appear and must be strictly adhered to, otherwise, serious injury
or equipment malfunction could result.
MIL 21000
Top Guided Single Seated Control Valves
Instruction Manual
Purchase Order No : ___________________________________________

TABLE OF CONTENTS
1. Introduction.........................................................................................................................3
2. General.................................................................................................................................3
3. Unpacking............................................................................................................................3
4. Installation ...........................................................................................................................3
5. Air Piping..............................................................................................................................4
6. Body Disassembly .................................................................................................................4
6.1 Threaded Trim........................................................................................................5
6.2 Quick-change Trim.................................................................................................5
7. Maintenance / Repair ...........................................................................................................7
7.1 Threaded Seat Ring Removal ................................................................................7
7.2 Guide Bush Removal..............................................................................................7
7.3 Lapping Seats ........................................................................................................7
7.3.1 Threaded Trim ........................................................................................7
7.3.2 Quick-change Trim.................................................................................8
7.4 Lo-dB Plug .............................................................................................................9
7.5 Plug Stem Pinning..................................................................................................9
7.5.1 Replacing Plug and Stem........................................................................9
7.5.2 Replacing Existing Stem only..................................................................9
7.6 Packing Box..........................................................................................................11
7.7 Soft Seat Construction.........................................................................................12
7.8 Stroke Change.....................................................................................................13
8. Valve Body Reassembly......................................................................................................13
8.1 Threaded Trim......................................................................................................13
8.2 Quick-change Trim...............................................................................................14
8.3 High Pressure & Angle Design .............................................................................15
9. Bellows Sealed Valve..........................................................................................................15
9.1 Bellow Sealed Valve Disassembly........................................................................15
9.1.1. Threaded Trim......................................................................................15
9.1.2 Quick Change Trim...............................................................................16
9.2 Repair...................................................................................................................16
9.2.1 Plug / Stem Bellows / Bonnet Extension S/A..........................................16
9.2.1.1 Replacing of Existing Plug and Stem- Bellow S/A..................16
9.2.1.2 Replacing of Existing Stem-Bellow S/A only..........................17
9.3. Plug And Seat Ring Seating Surfaces ..................................................................18
9.4 Bellow Sealed Valve Reassembly ........................................................................18
9.4.1 Threaded Trim......................................................................................18
9.4.2 Quick- Change Trim..............................................................................19
Parts List............................................................................................................................19
Note: Easily replaceable Pressure gauges for Air sets and externally mounted Pressure gauges of
positioners are normally dismantled, separately packed and bound to the actuator yoke as a
precaution against transit damages. This may be noted while opening the boxes.
Warning: Do not lift large size valves by the actuator. Lifting lugs provided on the actuators are for lifting
the actuator alone.
2

1. Introduction
The following instructions should be thoroughly
reviewed and understood prior to installing,
operating or performing maintenance on this
equipment. Throughout the text, safety and/or
caution notes will appear and must be strictly
adhered to, otherwise, serious injury or
equipment malfunction could result.
MIL has a highly skilled Aftermarket
department available for start-up, maintenance
and repair of our valves and component parts.
Arrangements for availing their service can be
made through your local representative or
Aftermarket department. In addition, a
regularly scheduled training program is
conducted at our plant, to train customer
service and instrumentation personnel in the
3. Unpacking
Warning: Care must be exercised when unpacking the valve to prevent damage to the
accessories and component parts. Should any problems arise, contact your local
representative or KSB MIL Aftermarket department. Do not remove end protection
cover before installation.
4. Installation
Caution: Before installing the valve in the line, clean piping and flush the line to
remove all foreign material such as welding chips, scale, oil, grease or dirt. End flange
gasket surfaces must be thoroughly cleaned to ensure leak proof joints.
Caution: Skilled service personnel to be
engaged for start up, maintenance and
repair of the valve.
Caution: Always use original MIL
replacement parts while performing
maintenance.
2. General
21000 series single ported top guided control
valves are designed with built-in versatility
making them well-suited to handle a wide
variety of process applications.
Standard construction offers a contoured plug
(21000 series) with a threaded seat ring or a
quick change seat ring. The heavy top plug
guiding provides maximum support to ensure
plug stability.
Tight Shut-off Class IV leakage is standard.
Optional constructions meet ANSI/FCI 70.2
Class V and Vl requirements.
Optional Low Emission Packing (Eco-lock) is
available to assure compliance with the fugitive
emission norms.
Replacing the conventional plug with the single
stage Lo-dB / anti-cavitation design (21700
series) provides excellent noise / cavitation
attenuation.
The 21800 / 21900 series double stage, anti-
cavitation / low noise valves are derived from
the 21700 single stage anti-cavitation valve
through a modification to the cage and plug.
Substitution of the standard cage, with a multi-
hole cage permits the pressure drop to be split
between the two stages effectively.
These installation and maintenance instructions
apply to all sizes and ratings of the MIL 21000
series control valves regardless of the type of
trim used. Recommended spare parts required
for maintenance are listed in parts reference of
page 15. The model number, size, rating and
serial number of valve are shown on the
identification tag located on the actuator. Refer
to Figure 1 to identify valve nomenclature.
3
operation, maintenance and application of MIL
Control Valves and Accessories. Also when
performing maintenance, please ensure that only
original MIL replacement parts are used. When
specifying parts, always include Serial Number
of the valve.

4
To allow in-line inspection, maintenance or
removal of the valve without service
interruption, provide a manually operated stop
valve on either side of the MIL 21000 series
valve with a manually operated throttling valve
mounted in the by-pass line. (See figure 2)
Numbering System
Figure 1
Body Series Plug Type Trim
Characteristic Cage Type
21. Top Guided
Globe
70. Top Guided
Angle
0. Undefined
1. Contoured
7. Single Stage Anti-cavitation / Lo-dB
8. Double Stage Anti-cavitation
9. Double Stage Lo-dB
0. Undefined
1. Linear
2. Equal %
3. Customised
X. On-Off
0. Undefined
4. Quick Change
5. Threaded
6. Soft Seat
Caution: The valve must be installed so
that the controlled substance will flow
through the valve in the direction
indicated by the flow arrow located on
the body.
Unless otherwise specified, the recommended
orientations are.
ŸWith contoured plug (21100) or Lo-dB plug
(21700/21900): flow-to-open
ŸOn anti-cavitation design (21700/21800):
flow-to-close
Main Line
By-Passs Line
By-Passs Valve
Control Valve
Isolation Valve Isolation Valve
Figure 2
Caution: Where insulation of the valve
body is required, do not insulate the
valve bonnet. Takenecessary protective
measures for personal safety.
5. Air Piping
Unless otherwise specified, the connection to the
actuator tubing shall be 1/4" NPT or ½" NPT.
Use the tubing equivalent or higher to the
connection size. Refer MIL valve specification
sheet of respective valves for more details. All
Warning : Do not exceed supply pressure
indicated on tag plate located on the
yoke of the actuator.
6. Body Disassembly
Caution: New packing & gaskets sets
should be on hand before disassembling
the valve, since itis recommended that
new packing & gaskets be used during
reassembly.
Access to the internal components of the body
should be accomplished with the actuator
removed. To remove the actuator from the
connection joints should be free of leaks.
body, refer to the appropriate actuator
instructions.
Warning: Prior to performing
maintenance on the valve, isolate the
valve and vent the process pressure.
Cut off supply air line and pneumatic or
electric signal line.

Figure 3
Threaded Seat Ring - Contoured Plug-full Capacity
1
3
5
9B
7
11
8
13
2
4
6
22
10
12
14
15
9A
(Optional)
6.1 Threaded Trim (Figure 3 or 5)
After removing the actuator, disassemble the body
using the following procedure :
Note: Refer respective instruction
manuals of actuators for removal of
actuators.
A. If there is a leak detector connection on
the lateral NPT port of the bonnet,
disconnect this piping as well.
B. Remove body stud nuts (11).
C. Remove bonnet (9B), and plug stem (1)
and plug (14) sub-assembly together as
one unit.
Note : Spiral wound body gaskets (12)
are standard in the 21000 series design
and it is imperative that a new gasket
be installed each time the valve
isdisassembled.
D. Remove packing flange stud nuts (3),
packing flange (4) and packing follower
(5).
E. Remove plug (14) and plug stem (1) sub-
assembly from the bonnet (9B).
Caution: Care must be taken to avoid
damage to the plug and plug guide.
F. Remove existing packing(7) in the bonnet.
G. Bonnet (9B), plug (14), bushing (8) and
seat ring (15) may now be inspected for
wear and service damage. After
determining the maintenance required,
proceed to the appropriate section of this
instruction manual.
6.2 Quick-Change Trim(Figure 4 or 7)
After removing the actuator, disassemble the body
using the following procedure:
A. If there is a leak detection connection on the
lateral NPT port of the bonnet, disconnect
this piping as well.
5

D. Since the cage (17), seat ring (15) and seat
ring gasket (16) are held in place by the
bonnet, they may now be removed.
B. Remove body stud nuts (11).
C. Remove bonnet (9B), and plug stem (1) and
plug (14) sub-assembly together as one unit.
Note : Spiral wound gaskets (12 & 16)
are standard in the 21000 series design
and it is imperative that new gaskets
be installed each time the valve is
disassembled.
E. Remove packing flange stud nuts (3),
packing flange (4) and packing follower
(5).
F. Remove plug (14) and plug stem (1) sub-
assembly from the bonnet (9B).
Caution : Care must be taken to avoid
damage to the plug and plug guide.
G. Remove existing packing (7)
bonnet.
H. All components may now be inspected for
wear and service damage. After
determining the maintenance required,
proceed to the appropriate section of this
instruction manual.
in the
7. Maintenance & Repair
The purpose of this section is to assist
maintenance personnel by suggesting methods
of component maintenance, which is largely
dependent on the tools and machine shop
equipment available.
7.1 Threaded Seat Ring Removal
(Figure 3)
Threaded seat rings (15) are installed tightly by
the manufacturer, and after years of service they
Figure 4
17
16
15
Quick Change Trim - Contoured Plug-full Capacity
Warning : When using heating devices,
ensure that proper safety practices are
observed. Flammability and toxicity of
the process fluid must be considered and
proper precautions to be taken.
6
may be difficult to remove.
To facilitate removal, seat ring wrenches can be
fabricated to engage the seat ring lugs and
adapted to a standard wrench. If the seat ring is
exceptionally resistant to removal, the
application of heat or penetrating oil should be
helpful.

7.2 Guide Bush Removal
The guide bush (8) is press fit into the bonnet
and does not normally require replacement. If
necessary, it may be pulled or machined out.
When machining the bush out, care must be
taken to maintain proper dimensions and
tolerances in the bonnet. These will be
furnished upon request.
7.3 Lapping Seats
Lapping is the process of working the valve
plug against the seat ring with an abrasive to
produce a close fit. If valve leakage is excessive,
lapping becomes necessary. The plug and seat
ring seating surfaces should be free of large
scratches or other defects, and the contact
surfaces of the seats should be as narrow as
possible. This may require dressing both parts
in a lathe. A good grade of fine grinding
compound is required for the lapping
operation.The compound should be mixed with
a small quantity of lubricant such as graphite.
This will slow the cutting rate and prevent
tearing of the seating surfaces. The amount of
lapping required depends on the materials,
condition of seating surfaces, and accuracy of
machining. lf a short period of lapping does not
visibly improve seating, there is usually no
advantage in continuing as excessive lapping
may result in rough seats. The only, remedy is
replacement or re-machining of one or both
parts. When lapping new plugs and seat rings,
begin with a medium compound and finish with
fine compound.
Note : Lapping should produce a line
contact area, not the entire surface, due
to the difference in seat angles.The
seating surface angle of the plug is 28
degrees and the seat ring is 30 degrees
(relative to the centerline axis).
7.3.1 Threaded Trim (Figure 3 )
1. Clean body gasket surface areas.
2. When seat has been removed, ensure
that the sealing surface in the body
bridge and the threads are thoroughly
cleaned.
3. lnstall and tighten seat ring using
fabricated wrench used for removal.
4. Apply lapping compound on the plug at
several spots equally spaced around the
seating area.
5. lnsert the stem and plug sub-assembly
carefully into the body until it is seated.
6. Place bonnet (9B) on the body and fasten
the bonnet to the body using four body
stud nuts (11) spaced equally apart. Apply
slight pressure and tighten evenly.
Caution : Before lapping, the plug and
stem sub-assembly must be concentric.
(See pinning operation, section 7.5).
Note : A sealant compatible with the
process fluid should be applied
sparingly to the seat ring threads and
sealing shoulder.
Caution: Do not over-tighten. Do not
strike seat ring lugs directly. This could
distort the seat ring resulting in seat
leakage.
Caution : Do not tighten nuts to final
torque specifications at this time. The
bonnet is used temporarily for guiding
purposes only.
Figure 5
Seat Lapping Device
7. lnsert two or three pieces of packing (7)
into the packing box to assist in guiding
the stem and plug during lapping.
8. Screw a drilled and tapped rod with a T-
handle onto the plug stem and secure with
a locknut (see Figure 5).
7

Note : As an alternative, drill a hole
through a flat steel plate and fasten to
the plug stem using two locknuts.
9. Apply slight pressure on the stem, and
rotate the stem in short oscillating strokes
(around 8 to 10 times). Repeat this step as
necessary.
Note : The plug should be lifted and
turned 90° each time before repeating
step (9). This intermittent lifting is
required to keep the plug and seat
ring concentric during lapping.
10. After completion of the lapping operation,
remove bonnet and plug. The seating area
of the seat ring and the plug must be
cleaned of all lapping compound in
preparation for reassembly. Do not
remove seat ring.
7.3.2 Quick-Change Trim (Figure 4 or 7)
1. CIean body gasket surface areas.
2. Install a new seat ring gasket (16) and insert
seat ring (15) in the body.
Note : Gasket (16) is temporarily placed
to hold the seat ring during lapping. It
is imperative to use a new gasket or a
test part having the same geometrical
characteristics in order to insure the
correct position of the seat ring during
lapping.
This gasket (or similar part) can be kept after
lapping for future lapping purpose.
Caution: The gasket used for lapping
should not be reused for the body
reassembly.
3. Apply lapping compound at several spots
equally spaced around the seating area of
the seat ring.
4. Insert the cage (17) into the body (9A).
5. lnsert the stem and plug sub-assembly
carefully into the body until it is
seated.
6. PIace bonnet (9B) on the body (9A).
7. Fasten the bonnet to the body using
four body stud nuts (11) spaced equally
apart. Apply slight pressure and
tighten evenly.
Caution : Do not tighten nuts to final
torque specifications at this time. The
bonnet is used temporarily for
guiding purposes only.
8. Insert two or three pieces of packing into
the packing box to assist in guiding the
stem and plug during lapping.
9. Screw a drilled and tapped rod with a T-
handle onto the plug stem and secure with
a locknut (see Figure 5).
Caution :Ensure that the seat ring (15),
cage (17) and bonnet (9B) are properly
aligned.
Note : As an alternative, drill a hole
through a flat steel plate and fasten to
the plug stem using two locknuts.
10 . Apply slight pressure on the stem, and
rotate the stem in short oscillating strokes
(around 8 to 10 times). Repeat this step
as necessary.
Caution: Avoid over-lapping as this can
cause damage to the seating surface
rather than
improve leakage performance.
Note : The plug should be lifted and
turned 90° each time before repeating
Step (10). This intermittent lifting is
required to keep the plug and seat ring
concentric during lapping.
11. After completion of the lapping
operation, remove bonnet and internal
parts. The seating area of the seat ring
and the plug must be cleaned of all
lapping compound in preparation for
reassembly.
8

7.4.Lo-dB PIug (Figure 6 or 7)
The procedures used for performing
maintenance on a valve equipped with Lo-dB
plugs (21700/21800/21900 series) are the same
as those used for Threaded or Quick Change
Trim.
Caution : Maintenance of the plug
should be limited to cleaning of the
ports and the procedures defined
under Sections 7.3 (Lapping) and 7.5
(Pinning) as required.
Figure 6
Quick Change Trim - Single Stage Lo dB Trim
Figure 7
Quick Change Trim - Double Stage Lo dB Trim
7.5 PIug Stem Pinning
Plug stem pinning in the field may be
required for the following:
— Replacing of existing plug and stem, or
— Replacing of existing stem only
7.5.1 Replacing of Existing Plug and Stem
If it is necessary to replace the plug, then the
plug stem must be replaced at the same time.
The original pin hole in an existing stem will
not provide the necessary fit, and might
seriously impair the strength of the assembly.
A. Reference Marking on the Plug Stem
Measure the depth of the pilot recess in
the plug (Dimension X in Figure 8), and
make a reference mark on the plug stem at
the same distance from the thread.
Note: While pinning is being
performed, care must be taken not to
damage the seating surface or plug
guide. Always use a soft metal or
plastic vice jaws with cylindrical
features to hold the plug guide area
(see Figure 8).
B. Screwing Stem to Plug
Hold the plug (with vise jaw assembly) in
a vise.
Lock two nuts against each other on the
end of the new plug stem, and screw the
stem solidly into the plug using a wrench
on the upper nut. When properly
assembled, the reference mark (see Section
A above) should be flushed with the end
of the plug guide.
17
14
18
14
C. Drilling the New Parts
If the plug is already fully drilled (typical for
440C hardened stainless steel material or
solid stellite), then drill the stem to the same
diameter (diameter C in Figure 8) as the plug
shank hole.
If the plug guide area has a center mark,
ŸPlace the plug guide on a V-block and
use a suitable drill size to either:
ŸMatch the hole size in the plug, or
match diameter C (see Figure 8)
ŸDrill through the plug-stem assembly.
If the plug guide area does not have any hole
or any center mark,
9

7.5.2 Replacing of Existing Stem Only
A. Removing Existing Pin and Stem
Place the plug guide on a V-block and use a
drift punch to drive out the old pin.
Hold the plug guide in a vise.
Lock one nut against another at the end of
the plug stem. Using a wrench on the
lower nut, unscrew the stem from the
plug. The stem is removed by turning it
counterclockwise.
B. Screwing Stem to Plug
Refer to step B of the previous section on
'Replacing Plug and Stem'.
Figure 8
Plug Stem Pinning
Plug Stem
Dia. "B"
Pin Hole
Dia "C"
½ 12.7 0.138 3.50 1.25 32.00 2.20 56.00 0.50 13
5/8 15.88 0.138 3.50 1.55 39.50 - - 0.63 16
3/4 19.05 0.197 5.00 1.88 47.50 4.63 117.50 0.75 19
1 25.40 0.197 5.00 2.50 63.50 5.59 142.00 1.00 26
Standard Valve Bellow Sealed Valve
Note : If it is necessary to drill out the
pin, use a drill bit slightly smaller than
the pin diameter.
C. Drilling the New Stem
Note : If the hole in the plug guide has
been slightly damaged while removing
the old pin, choose a drill bit and a pin
with a slightly larger diameter than the
normal pin.
Place the plug guide on a V-block and use
a suitable size drill bit to drill the stem
(use the hole in the plug as a guide).
ŸMeasure dimension D based on the
plug guide diameter and stem
diameter (see Figure 8).
ŸPlace the plug guide on a V-block,
and make a center mark on the plug
guide area using a center punch.
ŸDrill through the plug-stem assembly
using a suitable size drill bit.
In all cases after drilling : Remove any
burrs from the plug guide hole by
making a slight chamfer.
D. Pinning the Plug-Stem Assembly
Select the correct size pin based on the
plug guide diameter and stem diameter
(see Figure 8). Apply a small amount of
grease on the pin and hand assemble it
into the hole in the plug.
Press fit the pin into the hole using a
hammer. Complete the pinning operation
by taking care to ensure that the pin is
recessed by the same amount at both
sides (see Figure 8).
After the plug has been pinned, it should
be placed in a lathe to insure it is
concentric with the stem. If the assembly
is not running true, then the stem should
be placed in a collet with the plug guide
against it and the plug should be
adjusted. Alignment of plug stem can be
performed by means of a soft faced
mallet.
mm mm
"D"
"X"
mm mm mmin. in. in. in. in.
10

Note: For any type packing do not
change the sequence of packing
arrangement. Use the packing as a set
only.
D. Pinning
Select the correct size pin based on the
plug guide diameter and pin hole diameter.
Proceed as described in part D of the
previous section 'Replacing Plug & Stem',
taking care not to damage the plug guide
area. Ensure plug stem alignment
following the pinning operation.
7.6 Packing Box (Figures 9 to 11)
Packing box maintenance is one of the principal
actions in routine servicing. Tightness of the
packing is maintained by packing compression.
Compression is achieved by evenly tightening
the packing flange nuts (3) against the packing
flange (4). Care must be taken not to over
tighten as this could prevent smooth operation
of the valve. If all compression is used up and
the valve leaks, then new packing is required.
The packing is available as a set of lower and
upper packing. The height of the lower and
upper packing set is same for standard packing.
Due to the difference in the height for Eco-lock
packing, the packing sets are labeled as lower
packing and upper packing. The upper packing
set will be larger than lower packing set for Eco-
lock.
Note: While replacing packing, replace
the upper packing set completely
Caution : Valve must be isolated and the
pressure vented before performing
packing box maintenance.
Proceed as follows :
A. Disconnect the actuator stem from the
valve to maintain a gap to insert the
packing set
B. Loosen and remove packing flange nuts
(3).
C. Raise packing flange (4), and packing
follower (5) up the valve stem.
Note: They may be taped in place to
keep them out of the way before
proceeding.
D. By means of a hooked instrument, remove
packing (7) ensuring not to damage the
sealing surfaces of the packing box or plug
stem.
E. Replace packing (7) referring to Figure 9
for correct amount of packing to place
above the spacer.
Note : Assemble and compress rings
one at a time into packing box. If rings
are skive cut, the skive cut of each
packing ring must be placed about 120
degrees apart.
Figure 9
Standard Packing Box
Figure 10
Eco-Lock
Figure 11
Standard Packing
Box With Live Loading
Plug Stem
Packing Nut
Packing Flange
Packing Follower
Packing Stud
Packing
Bonnet
Plug Stem
Packing Nut
Packing Flange
Packing Follower
Packing Stud
Eco-lock Packing
Bonnet
Plug Stem
Packing Nut
Packing Flange
Packing Follower
Packing Stud
Packing
Bonnet
Disc Spring
11

Soft Seating is provided in the MIL 21000
series valve with a soft seated seat ring for Cv
less than or equal to 6 and for higher Cv, the
soft seating is provided in the plug.
If the PTFE insert in the seat ring is damaged
or eroded, the seat ring, as such has to be
F. Replace packing follower (5) and packing
flange (4).
G. Replace and tighten packing stud nuts (3).
Caution: Do not over-tighten.
H. Put valve back in service and tighten
packing only as much as is necessary to
stop leaking.
Note: A spring loaded follower
assembly is used to maintain a constant
load on the packing, and is necessary
for thermal cycling applications. As the
definition of thermal cycling can vary,
and processes are potentially subject to
unpredicted thermal gradients. Both
standard and Eco-Lock systems are
available with the spring loaded
follower (Figure 11).
Caution: Packing box should be clean
and free of burrs, rust, and any foreign
matter. Parts can be cleaned with
denatured alcohol.
Note: In an emergency, string packing
may be used as a temporary repair only.
It must be replaced with the correct
packing as soon as possible.
Caution: For Eco-lock packing, inner and
outer packing to be replaced as a set only.
7.7 Soft Seat Construction (Figure 12)
Note: MIL Ecolock packing (Fig 10) is a
high performance system to keep
fugitive emissions within allowable
limits. The packing is provided with the
inner packing and outer packing as a
set. It consists of V and double V
packing rings with varying density,
which is designed to prevent fugitive
emission from the packing effectively.
replaced. The PTFE insert is crimped to the seat
ring and is not replaceable.
The soft seat plug is provided with a
replaceable PTFE insert. It may be replaced as
follows.
Caution: The plug shank is the plug
guiding area. Extreme care to be taken,
while dismantling the PTFE insert, to
prevent any score marks or damage to
the shank area.
A. Loosen the Set Screw.
Note: The plug skirt is provided with a
slot, for valve sizes upto 2". A bar can
be inserted in the slot for unscrewing
the plug skirt. For sizes above 2" , two
machined holes are provided in the plug
skirt, into which a tool (fabricated with
appropriate size pin) can be inserted for
removal.
B. Carefully hold the plug firmly with soft
jaws, in a vise and unscrew and remove
the plug skirt portion with the tool.
C. Remove the insert and O ring (for 3" and
above only ).
D. Carefully clean the metallic parts and
replace the insert and O ring ( for sizes 3"
and above) with new items.
E. Place the insert and O ring (with a light
coat of lubricant compatible with service
fluid) in the plug shank. Install the plug
skirt into the shank and hand tighten the
plug skirt till the top of the skirt presses
the insert evenly.
F. Hold the shank firmly in the soft jaw of a
vise and tighten the skirt portion using the
tool. The plug skirt is tightened firmly,
allowed to set for 4 hours, then
retightened, again set for 4 hours and
retightened. This is to allow the insert to
cold flow into the place on the plug
subassembly.
G. Tighten the screw firmly into the plug.
Caution: The shank OD is the plug
guide. Extreme care must be taken to
prevent scoring or marring this surface.
Failure to do so could result in damage
to the guide bushing and destruction of
the plug. Two flats are provided for
holding.
12

Caution: The plug tip must be tightened,
allowed to set for approximately 4
hours, re-tightened, allowed to set
another 4 hours, then tightened one
more time. The purpose of this
tightening sequence is to allow the
insert material to “cold flow” into place
on the plug subassembly.
Figure 12
Soft Seated Plug & Seat(optional)
O Ring
Set Screw
PTFE Insert
Plug Shank
MIL 21000 series valves are equipped with
actuators. It is possible, in some cases, to
change the actuator stroke.
This relocation can be easily performed at site
provided the plug stem is adapted to the new
needed stroke. If a shorter stroke is needed, the
new plug stem shall be longer by the difference
between old and new stroke. It shall be the
other way around, if the new stroke is longer,
the new stem shall be
7.8 Stroke Change
shorter by the same difference as indicated
above.
The new stem is available from our Aftermarket
department. When ordering, do not forget to
mention original valve serial number and new
needed stroke.
8. Valve Body Reassembly
After completion of the required maintenance, the
valve should be reassembled using the following
procedures:
Note: If any of the following steps were
completed during maintenance, then
proceed to the next step.
8.1 Threaded Trim (Figure 3 or 5)
A. CIean all gasket mating surfaces.
B. Apply a small amount of sealant to the
seat ring threads and sealing shoulder.
Install seat ring into valve body.
Note: A sealant compatible with the
process should be applied sparingly.
C. lnstall and tighten seat ring using wrench
used for removal.
Caution: Do not over-tighten. Do not
strike seat ring lugs directly. This could
distort the seat ring resulting in
unwarranted seat leakage.
Caution: Ensure any lubricant used is
compatible with service conditions.
D. Carefully install plug and stem assembly.
Note: Valve should be lapped before
final assembly. See section 7.3 on
'Lapping Seats'.
E. Install body gasket (12).
Note: Spiral wound body gaskets (12)
are standard in the 21000 series
design. It is imperative that a new
gasket be installed each time the valve
is disassembled.
F. Assemble bonnet (9B) and body stud nuts
(11). Bonnet must be positioned so the
packing flange studs are at 90° to the flow
center line.
Caution: Tighten nuts (11) until metal
to metal contact is obtained with
proper bolt torque. Refer to Figure 14
for proper bolt torque and tightening
sequence specifications.
G. lnsert lower packing set (7)and lantern ring
or spacer (6). Refer to Section 7.6 for
proper packing assembly procedure for
standard or optional designs.
H. Install upper packing set and packing
follower (5) and packing flange (4).
I. lnstall packing flange stud nuts (3).
13

J. For actuator assembly and plug stem
adjustment, proceed to the actuator
instruction manual.
Caution: Do not overtighten (See section
‘7.6. Packing Box’).
Valve Size
(Inch) ASME Rating Class Stud Size Qty
(Nos)
Torque
(Nm)
0.5
150-600 1/2-13 UNC-2A 4 40
150-600 1/2-13 UNC-2A 8 30
900-2500 1-8 UNC-2A 4 320
150-600 1/2-13 UNC-2A 8 30
900-2500 1-8 UNC-2A 4 320
150-600 1/2-13 UNC-2A 8 30
900-2500 5/8-11 UNC-2A 4 320
0.75
1
1.5
150-600 1/2-13 UNC-2A 8 30
2900-2500 5/8-11 UNC-2A 8 100
2500 3/4-10 UNC-2A 8 160
2.5 2500 3/4-10 UNC-2A 8 160
3
150-600 5/8-11 UNC-2A 6 60
600 3/4-10 UNC-2A 8 100
900-1500 3/4-10 UNC-2A 8 210
4150-300 5/8-11 UNC-2A 8 60
600 1-8 UNC-2A 8 190
6150-300 5/8-11 UNC-2A 12 60
600 1-8 UNC-2A 12 180
8
10
150-300 1 1/4-8 UN-2A 12 170
150-300 1 1/4-8 UN-2A 12 250
600 1 1/4-8 UN -2A 12 500
Figure 13 - Bolting Torques And Tightening Sequence
8.2 Quick-Change Trim (Figure 4 or 7)
A. CIean all gasket mating surfaces.
B. Install seat ring gasket (16) and seat ring
(15).
Note: Spiral wound gaskets (12 & 16) are
standard in the 21000 series design. It is
imperative that a new gasket beinstalled
each time the valve is disassembled.
C. Install cage (17).
D. Carefully install plug and stem assembly.
Note: Valve should be lapped before final
assembly. See Section 7.3 on 'Lapping
Seats'.
E. Install body gasket (12).
F. Assemble bonnet (9B) and body stud nuts
(11) and tighten. Bonnet must be
positioned so the packing flange studs are
at 90° to the flow center line.
Caution: Care must be taken to
ensure that the cage, seat and bonnet
are properly aligned in the body.
14

Cage should be installed with ports at
lower end, near seat ring. Tighten nuts
(11) until metal to metal contact is
obtained with proper bolt torque. Refer
to Figure 14 for proper bolt torque and
tightening sequence specifications.
G. lnsert lower packing set (7) and lantern
ring or spacer (6). Refer to Section 7.6 for
proper packing assembly procedure for
standard or optional designs.
H. Install upper packing set and packing
follower (5) and packing flange (4).
I. lnstall packing flange stud nuts (3).
J. For actuator assembly and plug stem
adjustment, proceed to the actuator
instruction manual.
Caution: Do not overtighten
(See Section ‘7.6. Packing Box’).
Figure 14
High Pressure Design
17
16
16
8.3 High Pressure & Angle Design
(Figures 14 & 15)
Standard trim is used within these optional
body configurations. Refer to the applicable
sections within this instructions manual.
Figure 15
Angle Body Design
9. Bellow Sealed Valve
Caution: Since this is a sealing bellows,
the plug stem should never be turned
under any circumstances.
There is a built-in anti-rotation feature,
consisting of a locking on the plug stem that
slides into a rectangular slot machined in the
upper bushing of the bellows (see Figure 16 &
17). It is important to disconnect the actuator
from the valve before changing the actuator
rotational position.
9.1.Bellow Sealed Valve Disassembly
Note: Concentric serrated metallic
gaskets are standard in the 21000 BS
series design. It is recommended that
new gaskets are installed each time
when the valve is disassembled. In the
case of quick- change design, for seat,
spiral wound metalic gaskets are
used.
9.1.1 Threaded Trim
After removing the actuator, disassemble the
body S/A using the following procedure:
A. Disconnect the leak-off circuit from the
15
bonnet (if this option is included). Remove
bonnet bolts (21) from the bonnet (9B).
B. Remove packing flange stud nuts (3),
packing flange (4) and packing follower
(5). Remove bonnet (9B).
C. Remove existing packing (7).
D. Remove body stud nuts (11).
E. Remove bonnet extension (23), stem
bellows S/A (19) and plug (14) at the
same time.
F. Remove the plug pin (13), then remove the
plug from the plug stem (1). (See section
9.2.1.1 for unpinning the plug stem).
G. Remove stem bellows S/A (19) by the top
of the bonnet extension (23). If necessary,
disengage the upper bushing
of assembly using a screwdriver in the
groove provided for this purpose.
H. Remove the bonnet and spacer gaskets
(20) and the body gasket (12).
I. Bonnet extension (23), plug (14), guide
bushings (8) and seat ring (15) may now
be inspected for wear and service damage.
After determining the maintenance
required, proceed to the appropriate
section of these instructions.

Note: A lower mechanical stop has been
provided to prevent damage of the
bellows during this step.
Figure 16
Bellows Sealed Valve - Clamped Seat
17
16
17
16
19
20
23
22
21
9.1.2 Quick-Change Trim
Removal of the quick-change trim is
accomplished using the same procedures as
removal of the threaded trim. However, after
the bonnet extension (23) has been removed
from the body, remove the cage (17), the seat
ring (15) and the seat ring gasket (16).
9.2 Repair
The purpose of this section is to provide
recommended maintenance and repair
procedures. These procedures assume the
availability of standard shop tools and
equipment.
9.2.1 Plug/Stem Bellows/Bonnet
Extension S/A
Plug stem pinning in the field may be
required for:
§ Replacing of existing plug and stem-
bellows S/A
§ Replacing of existing stem-bellows S/A
only
If the plug needs replacing, the stem-bellows
subassembly should be replaced at the same
time. The original pin hole in a stem which is
being reused sometimes prevents a satisfactory
result being obtained and can also weaken the
plug-stem assembly. If the stem-bellows
subassembly is being replaced, the new assembly
can be fitted on an existing plug as long as it is
in good condition and the removal of the pin
has not deformed the hole or damaged it in any
other way.
Note: Always use soft metal vise jaws to
hold the plug guide surface. Failure to
take this precaution could result in
damage to the plug guide surface
during pinning (see figure 17).
Note: Be careful not to damage the
plug seating surface during pin
removal and assembly operations.
A. Unpinning the Plug Stem- Bellow S/A
9.2.1.1
bellows S/A
Replacing of existing plug and stem-
§Disconnect the leak-off circuit from the
bonnet (if this option is included). Remove
bonnet bolts (21) from the bonnet (9B).
§Remove packing flange stud nuts (3),
packing flange (4) and packing follower (5).
Remove bonnet (9B).
§Remove existing packing (7).
§Remove body stud nuts (11).
§
extension (23) to allow access to the plug pin
(13). Place the plug guide on a V-block.
Pull and hold the plug (14) out of the bonnet
§
pin (13).
Using a drift punch, drive out the existing
Note: If it is necessary to drill out the pin,
use a drill bit slightly smaller than the pin
diameter. Be careful not to damage the
hole of the plug guide.
16

§Lock two nuts against each other on the
end of the plug stem, and use a flat spanner
on the lower nut to prevent rotation while
unscrewing the plug from the stem. The
plug is removed by turning it counter-
clockwise.
§Remove the two nuts from the plug stem.
B. Mounting of the Plug-Stem/Bellows
S/A into the Bonnet Extension
§Clean all contact surfaces of the bonnet
extension (23) and the plug-stem/bellows
S/A.
§Assemble a new gasket (20) on the upper
flange of the bonnet extension.
§Insert the new stem-bellows S/A through the
top hole into the bonnet extension (23).
Note : Be careful not to damage the
seating surfaces of the bellows bushing
C. Plug Stem Pinning
§Lock two nuts against each other on the
end of the plug stem and use a flat spanner
on the upper nut to prevent rotation of the
stem-bellows S/A. Screw the plug onto the
lower part of the stem while inserting the
plug shank into the guide bushing (8) in the
bonnet extension (23).
§Pull and hold the plug (14) out of the
bonnet extension (23) to allow access to the
plug pin (13) area.
§If the plug is already fully drilled, (typical
for 440C hardened stainless steel material
or solid stellite), then drill the stem to the
same diameter (Diameter C in Figure 8) as
the Plug Shank Hole
If the plug guide area has a center mark,
place the plug guide on a V-block and use a
suitable size drill to either:
§Match the hole size in the plug, or
§Match diameter C (see Figure 8)
§Drill through the plug-stem assembly.
§If the plug guide area has no hole or any
center mark,
§Measure dimension D based on the plug
guide diameter and stem diameter (see
Figure 8).
§ Place the plug guide on a V-block, and
make a center mark on the plug guide area
using a center punch.
§Drill through the plug-stem assembly using
a suitable size drill bit. In all cases after
drilling: Remove any burrs from the plug
guide hole by making a slight chamfer.
Figure 17
MIL 21000 Bellows Sealed Construction
§Select the correct size pin based on the plug
guide diameter and stem diameter (see figure
8). Apply a small amount of grease on the
pin and hand assemble it into the hole in the
plug.
§Press fit the pin into the hole using a
hammer. Complete the pinning operation by
ensuring that the pin is recessed by the same
amount from both sides (see Figure 8).
9.2.1.2 Replacing Stem/Bellows S/A Only
A. Unpinning the Plug Stem-Bellow S/A
§Disconnect the leak-off circuit frm the bonnet
(if this is included). Remove bonnet bolts (21)
from the bonnet (9B).
§Remove packing flange stud nuts (3), packing
flange(4) and packing follower(5). Remove
the bonnet(9B).
17

§Remove existing packing(7).
§Remove body stud nuts (11).
§Pull and hold the plug (14) out of the bonnet
extension (23) to allow access to the plug pin
(13). Place the plug guide on a V-block.
Note: A lower mechanical stop has been
provided to prevent damage of the
bellows during this step
§Using a drift punch, drive out the existing
pin (13).
Note: If it is necessary to drill out the
pin, use a drill bit slightly smaller than
the pin diameter. Be careful not to
damage the hole of the plug guide.
§Lock two nuts against each other on the
end of the plug stem, and use a flat spanner
on the lower nut to prevent rotation while
unscrewing the plug from the stem. The
plug is removed by turning it counter-
clockwise.
§Remove the two nuts from the plug stem.
§Place the plug guide on aV-block and use a
suitable size drill bit to drill the stem (use the
hole in the plug as a guide)
B. Mounting of Plug Stem/Bellow S/A into
the Bonnet Extension
§Clean all contact surfaces of the bonnet
extension (23) and the plug-stem/bellows
S/A.
§Assemble a new gasket (20) on the upper
flange of the bonnet extension.
§Insert the new stem-bellows S/A through the
top hole into the bonnet extension (23).
Note : Be careful not to damage the
seating surfaces of the bellows bushing
C. Plug Stem Pinning
§Lock two nuts against each other on the
end of the plug stem and use a flat spanner
on the upper nut to prevent rotation of the
stem-bellows S/A. Screw the plug onto the
lower part of the stem while inserting the
plug shank into the guide bushing (8) in the
bonnet extension (23).
§Pull and hold the plug (14) out of the
bonnet extension (23) to allow access to the
plug pin (13) area.
§
suitable size drill bit to drill the stem (use
the hole in the plug as a guide)
Place the plug guide on aV-block and use a
Note: If the hole in the plug guide has
been slightly damaged while removing
of the old pin, choose a drill bit and a
pin with a slightly larger diameter than
the normal pin.
§Select the correct size pin based on the plug
guide diameter and stem diameter (see
figure 8). Apply a small amount of grease
on the pin and hand assemble it into the
hole in the plug.
§Press fit the pin into the hole using a
hammer. Complete the pinning operation by
ensuring that the pin is recessed by the same
amount from both sides (see Figure 8).
9.3 Plug and Seat Ring Seating Surfaces
It is not possible to lap the plug and seat ring
seating surfaces after the bellows has been
assembled to the stem. If the seat ring shows
signs of minor wear, it should be turned on a
lathe to clean up the worn area. The seating
surface of the seat ring is 30 degrees from
centerline axis. However, no more than 0.010
in. (0.25 mm) of material should be removed. In
cases where the seat ring cannot be repaired, or
if the plug is also damaged the only alternative
is to replace both parts.
9.4 Bellow Sealed Valve Reassembly
After completion of the required maintenance,
the valve should be reassembled using the
following procedure :
9.4.1 Threaded Trim
A. Clean all gaskets mating surfaces.
B. Apply a small amount of sealant to the
seat ring threads and sealing shoulder.
Install seat ring into valve body
Note : A sealant compatible with the
process should be applied sparingly
18

C. Install and tighten seat ring using wrench
used for removal.
D. Assemble the plug stem / bellow S/A using
9.2.1.1 or 9.2.1.2.
E. Install the bonnet extension and plug stem
bellow S/A together to the body.
F. Tighten the body stud nuts using torque
valves in the Figure 13.
Caution : Do not over-tighten
G. Insert the gasket over the plug stem S/A.
H. Install the bonnet (9B) and assemble bolts
(21). Bonnet must be positioned so the
o
packing flange studs are at 90 angle to
the flow centerline. Refer to table in
Figure 13 for proper bolt torque and
tightening sequence. The locking pin in the
plug stem/ bellow S/A must go through the
slot provided on the bonnet.
I. Insert packing set.
J. Insert packing follower and packing
flange.
K. Install packing flange studs nuts.
Caution : Do not over-tighten
9.4.2 Quick-Change Trim
A. Clean all gasket mating surfaces
B. Install seat ring gasket (16) and seat ring
(15).
Note : Spiral wound gaskets (12 & 16) are
standard in the 21000 series design. It is
imperative that a new gasket be installed
each time the valve is disassembled.
C. Install cage (17).
D. Assemble the plug stem / bellow S/A using
9.2.1.1 or 9.2.1.2.
E. Install the bonnet extension and plug stem
bellow S/A together to the body.
F. Tighten the body stud nuts using torque
valves in the Figure 13.
G. Insert the gasket over the plug stem S/A.
H. Install the bonnet (9B) and assemble bolts
(21). Bonnet must be positioned so the
o
packing flange studs are at 90 angle to
the flow centerline. Refer to table in
Figure 13 for proper bolt torque and
tightening sequence. The locking pin in the
pplug stem/ bellow S/Amust go through
the slot provided on the bonnet.
I. Insert packing set.
J. Insert packing follower and packing
flange.
K. Install packing flange studs nuts.
2
4
6
22
10
12
14
15
9A
1
3
5
9B
7
11
8
13
(Optional)
Parts List
19