Uni-Directional Knife Gate Valves

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Body :

The body is lugged type Wafer Design single piece of Cast steel / Stainless steel (Investment Cast upto 200 mm). It is designed to withstand pipeline stresses while in service. The body is available in variety of materials that provide corrosion and abrasion resistance. Guide Lugs are provided on the body to hold the gate securely against the raised face seat to assure positive shutoff. The body has drilled and tapped lugs on the outer rim drilled & tapped in accordance with different flange standards such as ANSI 150, ANSI 300, BS10 TD, BS10 TE, PN10, IS 1538 etc.

Gate :

Precision machined thick Stainless steel gate provides good sealing and smooth operation. The beveled knifelike edge pushes aside or cuts through solids in the flow stream. The gates are available in different materials to suit various applications.

Stem :

The Stem is of stainless steel with double start ACME threads, designed to reduce operating torque and for easier, faster operation & longer life.

Gland :

The Investment Cast Gland is of Cast steel / Stainless steel with precisely controlled dimensions to ensure minimum gap between Body and Gate to have better performance.

Gland Packing :

The Gland Packing is Multi-layered square PTFE Impregnated packing for complete leak tightness and to offer seal to the atmosphere. High temperature packing is available upto 1400 deg C and other options are available for different applications.

Yoke :

The heavy duty fabricated Yoke is designed to provide support, strength & withstand stresses.

Yoke Sleeve :

The Bronze Yoke Sleeve provides corrosion resistance and assures easy operation. A grease fitting provides lubrication to the sleeve and stem.

Seat Options :

The valves are available in metal seated and resilient seated round port designs.

Actuator :

The standard valves are provided with hand-wheel. The other actuators such as Chain Wheel, Lever, Bevel Gear, Pneumatic Cylinder & Electric Motor are available on request.

Size range

2″ (50 mm) to 104″ (2600 mm)
Handwheel Handwheel with Locking Arrangement Chain Wheel
The standard valves come with the Handwheel arrangement (Rising Stem Type)
Valve with non rising stem hand wheel and locking arrangement
A Chain Wheel is provided in place of hand-wheel in applications where the valve is located at an elevation.
Lever Pneumatic Electric
Lever actuators are suitable for smaller valves (below 300 mm). They are used where actuation forces are small and rapid valve operation is required or where space prevents use of standard hand-wheel or worm gear.
Pneumatic actuators are provided for on-off application service. The gate is operated by a double acting pneumatic cylinder. Accessories like solenoid valves, limit switches etc. are provided as per customer’s requirement / specification.
Electric Motor Actuators are provided for on-off or throttling applications. They are provided with manual over-ride arrangement to take care in case of power failure. The service conditions, type of application, speed of operation, electric
characteristics are the factors governing the actuator selection.
Pneumatic with Manual Override
Bevel Gear
This arrangement is provided in application where space limitations prohibit use of standard hand-wheel. A mechanical advantage makes operation of large size valves easier and faster.

Optional Accessories

Deflector Cone

Deflector cone is provided on the inlet of the valve for critical service application where abrasion is high. The Deflector cone is normally of Ni-hard material and protects the valve body. It is installed between the valve and the pipe flanges and diverts the abrasive material flow to the valve.

The typical application involve Bin bottom, for dry solids, mining slurries, fly-ash, bag-filter, cyclone bottom.


Ni-hard

Polyurethane

Purge Connection

The purge connections are used to flush the seat area and minimize the chance of material getting clogged on the seat, thus helping smooth operation of the gate.

Purge connections are located at 5 and 7 ‘O’ clock positions on 6″ and smaller size valves and at 3,5,7 and 9 ‘O’ clock positions on 8″ and larger size valves. The purge connection can also be provided in the chest area and is normally furnished with pipe plugs and are used only for flushing if required.

Pneumatic with Fail Safe System & Manual override

Surface Treatment

The valve components can be offered with protective coatings / surface treatment typically hard facing of seat areas (Stelliting / Nitriding of body, seat and gate edge) is done, depending on the application to increase the life expectancy.

Other Accessories

  • Locking Device
  • Extended Stem
  • Proximity Switches
  • Solenoid Valves
  • Limit Switches
  • Air Filter (Regulator)
  • Chain for chain-wheel actuator
  • Mating flanges & hardware

Basic Flange Drilling Dimensions

DN 50 – 600
Full Lugger Design
DN 700 & above
Flanged Design
NOTE : Blind Tapped holes on body chest area only
BS 10 Table ‘D’
SIZES Ød(PCD) n(Nos) Tap HoleØ
50 114.0 4 M16 17.5
65 127.0 4 M16 17.5
80 146.0 4 M16 17.5
100 178.0 4 M16 17.5
125 210.0 8 M16 17.5
150 235.0 8 M16 17.5
200 292.0 8 M16 17.5
250 356.0 8 M20 22
300 406.0 12 M20 22
350 470.0 12 M24 25
400 521.0 12 M24 25
450 584.0 12 M24 25
500 641.0 16 M24 25
600 756.0 16 M27 29
ANSI B16.5 class 150
SIZES Ød (PCD) n(Nos) Tap HoleØ
50 120.5 4 M16 19
65 139.5 4 M16 19
80 152.5 4 M16 19
100 190.5 8 M16 19
125 216.0 8 M20 22
150 241.5 8 M20 22
200 298.5 8 M20 22
250 362.0 12 M22 22
300 432.0 12 M22 25
350 476.0 12 M27 29
400 539.5 16 M27 29
450 578.0 16 M27 32
500 635.0 20 M27 32
600 749.5 20 M33 35
700 863.5 28 M33 35
800 978.0 28 M39 41
900 1086.0 32 M39 41
1000 1200.0 36 M39 41
1200 1422.0 44 M39 41
DIN PN 10
SIZES
Ød (PCD) n(Nos) Tap HoleØ
50
125
4 M16
19
65
145
4 M16
19
80
160
8 M16
19
100
180
8 M16
19
125
210
8 M16
19
150
240
8 M20
22
200
295
8 M20
22
250
350
12 M20
22
300
400
12 M20
22
350
460
16 M20
22
400
515
16 M24
26
450
565
20 M24
26
500
620
20 M24
26
600
725
20 M27
30
700
840
24 M27
30
800
950
24 M30
33
900
1050
28 M30
33
1000
1160
28 M33
36
1200
1380
32 M36
39

V-Orifice

The metal seated V-port design version of Knife Gate Valve is available for throttling application. The constant V-orifice is maintained to ensure maximum control accuracy.

Hopper Isolation Knife Gate Valve

This valve is specially designed for use as isolation valve for silos handling powders. The body design includes a large relieved area on the downstream side that can accommodate some material accumulation without affecting the closing operation of the valve. Tthese valves are typically mounted with seat facing downward under silo, the body is provided with large cast guides to support the material load on the gate. This design uses a thinner gate than standard knife gate valves as same is sufficient for the typical gravity flow situations where such valves are used. The valve is designed to be dust tight.

Body with relieved outlet area
and multiple cast gate supports

Flat edge beveled gate
Typical Applications
  • Gravity flow silo isolation
Specifications
Type Uni-directional knife gate valve
Size range 100,150,200,250, 300, 350, & 400mm
Pressure rating CWP-5 bar (75 psi)
Endstyle Flanged
Face-to face Proprietary
Drilling Proprietary
Body Cast iron
Seat Integral metal seat
Gate 304stainless steel
Stem SS 410, SS 304, SS 316
Superstructure Epoxy coated steel channel fabricated
Actuator options Hand wheel, chain wheel, pneumatic actuator

Coal Mill Knife Gate Valve

Typically these valves are used to isolate the coal mill from the boiler furnace and are normally kept open during service. They are closed to isolate the mill from the hot flames and gases in the boiler furnace during emergency shut downs and for routine maintenance. During normal operation, when the valve is open, mixture of air and fine pulverized fuel (eg., coal) at very high velocity passes through the valve- This is a very abrasive media and calls for a valve that offers minimum flow restriction and has internal parts with high erosion resistance.

A unidirectional flanged knife gate valve specially designed to meet these exacting service requirements. It features a body construction with the bore matching the pipeline bore which keeps the pressure drop in the valve to the minimum. This means there is no raised seat in the flow path as in the case of standard knife gate valves. The internal bore of the valve is usually hardfaced to provide high resistance to erosive wear.

This valve is designed to comply with the requirements of NFPA-85 (2001) standard which governs equipment used in coaf mills and associated piping.

These valves are normally supplied with a powered actuator, usually pneumatic or electric. Other actuation options are also available where required.

Design Highlights
Conformance  to   NFPA-8503 Designed   to   comply  with requirements of NFPA-S5 (2001)
Full bore Minimum resistance to flow with bore identical to pipe bore or more.
Hard faced valve bore For resistance to highly abrasive and continuous material flow the valve bore is provided with suitable hardfacing, Seat face steiliting is aiso available as an option.
Stem protection bellows For reliable operation in dusty environment.
Specifications
Type Uni-directional knife gate valve
Size range 100mm to 650rnm  (higher sizes on application)
Design Full port design conforming to NFPA-85 (2001)
Rating Designed to comply with the requirements of NFPA-85 (2001)
Endstyle Wafer- flanged standard; lugged versions also available
Drilling ANSI 1501b,& others
Body Carbon steel, stainless steel
Gate 304/316 Stainless steel
Packing PTFE impregnated syntex fibre as standard; other packing materials and wiper packing options available.
Purges Chest purges are provided as optional.
Actuator Pneumatic double-acting cylinder with nitrile/viton energized PTFE piston seal or electric actuator
Manual valves with rising stem handwheel or geared handwheel

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