FNW 6800 User Manual

Figure 6800

KNIFE GATE VALVES

STAINLESS STEEL BIDIRECTIONAL

RESILIENT SEATED KNIFE GATE VALVE

The  gure 6800 knife gate valve has an all cast stainless steel body and yoke with investment cast packing follower. It is a general purpose zero-leak bidirectional shutoff valve. Perimeter gate sealing is not pressure dependent, so there is no minimum differential needed for shutoff. Port sizing is similar to schedule 40 pipe, so the valve offers unrestricted ﬂ ow and minimal pressure drop.

Features

• Bidirectional Bubble-Tight Shutoff

• Maximum Pressure: 150 PSI CWP (30” is 50 PSI CWP)

• Maximum Temperature: 176°F (80°C)

• Non-Differential Pressure Dependent Shutoff

• Cast Stainless Steel Body, Yoke, & Packing Gland

• Thrust Needle Bearing

• Combination Chest Liner & Anti-Extrusion Strip

(Anti-Extrusion Strip Only on 14” and Larger Valves)

• Wire Reinforced & Retained Resilient Seat

• Stainless Steel Position Indication Arrow

• Stainless Steel Hardware

• Machined Gland Pocket Area

• Bonnetless, Outside Screw & Yoke

• Rising Stem

• Cast Iron Hand Wheel

• Gear-Operator Standard on 30” Valve

• Available in sizes 3” to 30”

• Standard design accommodates locking device

Standards

• Face-to-Face: MSS SP-81

• Flange Drilling: ANSI B16.5 (30” to MSS SP-44 Flanges)

• Testing: ○ Shell (Before Assembly): 1.5 Time Max. CWP (No Leak) ○ Seat: 1.1 Times Max. CWP (No Leak)

• Material: ASME B16.34

Figure Number Matrix

FNW 6800 Seat Size

SEAT CODE

Buna (Nitrile) = B (SS Wire Reinforced)

3 = M 4 = P 6 = U 8 = X

SIZE CODE

10 = 10 12 = 12 14 = 14 16 = 16

18 = 18 20 = 20 24 = 24 30 = 30

Cv & Weight

Size Cv Wt (Lbs)

3 565 44 4 1,040 53

6 2,440 88

8 4,460 139 10 6,250 181 12 9,400 229

Weights are for general reference only.

Size Cv Wt (Lbs)

14 12,500 364 16 16,500 397 18 21,400 463 20 27,000 573 24 39,700 617 30 60,000 882

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Hand wheel is heavy cast iron, with a rounded grip and epoxy coated hand wheel.

Double set screws prevent threaded-on hand wheel from backing off or coming loose.

Stainless steel needle bearings reduce hand wheel rim pull force.

Aluminum-Bronze thrust components for antigalling operation.

Grease  tting for maintaining smooth drive sleeve operation.

Cast stainless steel yoke arms provide optimum ﬂ exural rigidity.

Stainless steel position indication arrow is standard

Stem-to-gate clevis is deliberately loose to allow play in gate to minimize binding.

Stainless steel hardware is standard.

Horizontal clevis bolts provide ﬂ exibility of the gate during travel.

FEATURES

Multiple layers of PTFE impregnated square braid packing provides excellent gland sealing at full valve pressure differential.

Combination PTFE chest liner & anti-extrusion strips (anti-extrusion strips only on 14” and larger valves), enhance packing functionality while centering the gate. They also act as a gate wiper, and support the gate in horizontally mounted valves.

The single piece cast all stainless steel body is rugged and compact. It offers better leak tightness than fabricated or two-piece designs.

The gate is high-quality, ground- nished stainless steel. A generous gate thickness is well supported by the packing.

Port sizing is similar to schedule 40 pipe, so the valve offers unrestricted ﬂ ow and minimal pressure drop.

Perimeter gate sealing is not pressure dependent, so there is no minimum differential needed for shutoff.

Secured Wire

Reinforcement

Gate/Seat

Interference Fit

Perimeter Seat

Seat Seal Conﬁ guration

The  gure 6800 knife gate valve provides bubble-tight shutoff. When the valve is closed, there is a friction  t along the entire perimeter between the ﬂ at edge of the gate and the elastomer seat. This friction  t ensures tight shutoff without the requirement of a minimum line pressure, but is tight enough to maintain shutoff at maximum rated pressures as well. There is no recommended ﬂ ow direction because the seal is made at the gate’s edge, hence bidirectional ﬂ ow capability.

Seat seal retention is twofold. First, the seat is retained in a channel with a machined retention

Resilient Seat

Reinforcement Wire

Retention Lip

lip. This lip overhangs both sides of the seat, preventing seat removal from high velocity ﬂ ows. Secondly, the seat is reinforced with a heavy stainless steel wire. The ends of the wire are wrapped around gland bolts. The wire adds rigidity to the seat form which also prevents seat movement during high ﬂ ow or valve opening/closing operation.

Standard Materials

Ref.

Description Material Qty

No.

1 Body

1A Seat

2 Gate

3 Packing

Chest Liner

Anti

Extrusion

Strip

6 Gland

7 Gland Bolt

8 Gland Nut

9 Yoke Arm

10 Yoke Bolt

11 Stem

12 Clevis Bolt

13 Clevis Nut

14 Collar

15 Collar Bolt

16 Collar Nut

17 Hand Wheel Cast Iron, ASTM A126 Gr. B 1

18 Yoke Sleeve

Thrust

Needle

Bearing

20 Set Screws Stainless Steel, 304SS 2 (3”~24)

Position

Indicator

30 Gear-Op

Stainless Steel, ASTM A351

Gr. CF8M

Buna (Nitrile) with ASTM

A276 Type 304 Wire

Stainless Steel, ASTM A240

Type 316

PTFE Impregnated Syntex

Fiber

PTFE

Stainless Steel, ASTM A351

Gr.CF8

Stainless Steel 304,

ASTM A193 Gr. B8

Stainless Steel 304,

ASTM A194 Gr. 8

Stainless Steel, ASTM A351

Gr.CF8

Stainless Steel 304,

ASTM A193 Gr. B8

Stainless Steel, ASTM A276

Type 304

Stainless Steel 304,

ASTM A193 Gr. B8

Stainless Steel 304,

ASTM A194 Gr. 8

Stainless Steel, ASTM A351

Gr.CF8

Stainless Steel 304,

ASTM A193 Gr. B8

Stainless Steel 304,

ASTM A194 Gr. 8

Aluminum Bronze,

ASTM B148, UNS C95200

Stainless Steel, 2 (3”~24)

Stainless Steel, 304SS 1

Enclosed Type

Model BG03 (not shown)

3 (3”~24”)

4 (30”)

2 (3”~12”)

2 (14”~30”)

2~10

1 (3”~24)

2 (3”~8”)

4 (10”~24”)

2 (3”~8”)

1 (3”~24)

1 (30” only)

Figure 6800

KNIFE GATE VALVES

STAINLESS STEEL BIDIRECTIONAL

RESILIENT SEATED KNIFE GATE VALVE

Dimensions (inches)

Size A B C D E F G H J K N S

3 2.00 6.00 5.00 16.34 19.49 9.84 2 5/8”-11 0.39 2 2.95 0.47 4 2.00 7.50 6.22 18.31 21.26 9.84 2 5/8”-11 0.39 6 4.00 0.47 6 2.25 9.50 8.50 22.05 27.36 11.75 2 3/4”-10 0.43 6 6.00 0.57

8 2.75 11.75 10.63 25.59 33.27 15.98 2 3/4”-10 0.43 6 8.00 0.57 10 2.75 14.25 12.76 28.66 39.37 15.98 4 7/8”-9 0.49 8 10.04 0.69 12 3.00 17.00 14.76 33.46 46.46 20.00 4 7/8”-9 0.43 8 11.97 0.69 14 3.00 18.75 16.26 37.60 53.15 20.00 4 1”-8 0.51 8 13.11 0.75 16 3.50 21.25 18.50 41.34 58.27 20.00 6 1”-8 0.63 10 15.00 0.87 18 3.50 22.75 20.98 45.67 63.78 20.00 6 1-1/8”-7 0.59 10 16.93 0.94 20 4.50 25.00 23.03 50.39 70.47 20.00 8 1-1/8”-7 0.75 12 18.82 0.98 24 4.50 29.50 27.24 58.46 83.66 20.00 8 1-1/4”-7 0.91 12 22.64 0.98 30 4.62 36.00 33.75 81.00* 110.00 19.68 10 1-1/4”-7 0.94 18 28.74 1.12

* Dimension “D” for 30” valve is centerline of valve to centerline of gear-operator hand wheel shaft.

DOC: FNW680013 Ver. 8/2014

The contents of this publication are presented for information purposes only, and while effort has been made to ensure their accuracy, they are not to be construed as warranties or guarantees, expressed or implied, regarding the products or services described herein or their use or applicability. All sales are governed by our terms and conditions, which are available on request. We reserve the right to modify or improve the designs or specications of our products at any time without notice. Always verify that you have the most recent product specications or other documentation prior to the installation of these products.

FNW 6800 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual