Design Specifications for Knife Gate Valves
METAL TO METAL SEAT, 304/316 CAST STAINLESS STEEL KNIFE GATE VALVES (2"-24")
Valves shall be of the bonnetless knife gate valve type, rated for 150 PSI CWP. Flanges shall be drilled and tapped to ANSI B16.5, 150 pound standard with raised faces. Flange raised face machining shall be serrated-spiral or serrated-concentric grooves with a 125-250 RMS finish. Valve bodies shall be cast 304/316 stainless steel (CF8/CF8M) with an integral cast in seat. Valve face to face shall be in accordance with MSS SP-81.
Valves shall have 304/316 stainless steel gate. Gate shall be of the design and thickness to withstand full 150 PSI rated pressure with out permanent deflection to the gate.Gate shall have a rounded, beveled bottom. Seat and gate shall be machine finished for tight one way shutoff. Two gate wedges shall be provided to assist seating of the gate against the seat in the lower half of the valve body.
The packing gland shall be cast 304/316 stainless steel (CF8/CF8M) and shall have an adequate number of gland bolts to provide an even tightening of the packing by the packing gland. Packing shall be Teflon lubricated synthetic packing with a minimum of 4 rows of packing. Packing gland bolts, studs and nuts shall be type 304 stainless steel.
The valve yoke shall be cast 304 stainless steel (CF8). The valve yoke shall be the flat top design to allow bolt-on field installation of conversion of actuators without welding or machining of the yoke. The valve stem shall be 304 stainless steel with full ACME threads. The lifter shall be cast 304 stainless steel (CF8), welded to the stem and be a two horizontal bolt design. The stem nut shall be bronze. The stem nut retainer shall be of the enclosed type and shall be cast 304 stainless steel (CF8)
Manual actuated valves shall be handwheel operated. Bevel gear operators are recommended for valves 16" and above where frequent operation is required and/or where used in applications above 75 PSI.
Valves shall be designed, manufactured and tested in accordance with MSS SP-81, Standard Practice for "STAINLESS STEEL, BONNETLESS, FLANGED,WAFER,KNIFE GATE VALVES".
All valves shall be Figure 76 Knife Gate Valve or approved equal.
RESILIENT SEAT, 304/316 CAST STAINLESS STEEL KNIFE GATE VALVES (2"-24")
Valves shall be of the bonnetless knife gate valve type, rated for 150 PSI CWP. Flanges shall be drilled and tapped to ANSI B16.5, 150 pound standard with raised faces. Flange raised face machining shall be serrated-spiral or serrated-concentric grooves with a 125-250 RMS finish. Valve bodies shall be cast 304/316 stainless steel (CF8/CF8M). Valve face to face shall be in accordance with MSS SP-81.
Valves shall have 304/316 stainless steel gate. Gate shall be of the design and thickness to withstand full 150 PSI rated pressure without permanent deflection to the gate. Gate shall have a rounded bottom. The seat shall be positioned to seal around the perimeter of the gate for drip tight bi-directional shutoff in either direction and at any pressure from vacuum to 150 PSI. The resilient seat shall be a molded or extruded elastomer with an internal stainless steel rod for stiffening. Seat retainers shall be provided in the lower half of the valve body to retain the seat and guide the gate during closing. At least two gate guides shall be provided in the upper half of the valve body.
The packing gland shall be cast 304/316 stainless steel (CF8/CF8M) and shall have an adequate number of gland bolts to provide an even tightening of the packing by the packing gland. Packing shall be Teflon lubricated synthetic packing with a minimum of 4 rows of packing. Packing gland bolts, studs and nuts shall be type 304 stainless steel.
The valve yoke shall be cast 304 stainless steel (CF8). The valve yoke shall be the flat top design to allow bolt-on field installation of conversion of actuators without welding or machining of the yoke. The valve stem shall be 304 stainless steel with full ACME threads. The lifter shall be cast 304 stainless steel (CF8), welded to the stem and be a two horizontal bolt design. The stem nut shall be bronze. The stem nut retainer shall be of the enclosed type and shall be cast 304 stainless steel (CF8)
Manual actuated valves shall be handwheel operated. Bevel gear operators are recommended for valves 16" and above where frequent operation is required and/or where used in applications above 75 PSI.
Valves shall be designed, manufactured and tested in accordance with MSS SP-81, Standard Practice for "STAINLESS STEEL, BONNETLESS, FLANGED,WAFER,KNIFE GATE VALVES".
All valves shall be Figure 77 Knife Gate Valve or approved equal.
FABRICATED 304/316 STAINLESS STEEL LINED KNIFE GATE VALVES (30"-72")
Valves shall be of the bonnetless knife gate valve type, with pressure ratings as required by the customer. Flanges shall be drilled and tapped to ANSI B16.1, 125 lb. Flanges shall be raised face and machined with serrated-spiral or serrated-concentric grooves with a 125-250 RMS finish. Valve body shall have 304/316 stainless steel body liner, seat (if metal to metal seat), packing box and raised faces (all wetted parts) and carbon steel body flanges, exterior stiffeners, packing gland and yoke.
Valves shall have 304/316 stainless steel gate. Gate shall be of the design and thickness to withstand full design pressure with out permanent deflection to the gate.
FOR METAL SEATED VALVES:
Seat and gate shall be machine finished for tight one way shutoff. Two gate wedges shall be provided to assist seating of the gate against the seat in the lower half of the valve body. On valves 48" diameter and above, the gate will be square bottom.
FOR RESILIENT SEATED VALVES:
Gate shall have a rounded bottom. The seat shall be positioned to seal around the perimeter of the gate for drip tight bi-directional shutoff in either direction and at any pressure up top the design pressure. The resilient seat shall be a molded or extruded elastomer with an internal stainless steel rod for stiffening. Seat retainers shall be provided in the lower half of the valve body to retain the seat and guide the gate during closing. At least two gate guides shall be provided in the upper half of the valve body.
The packing gland will be fabricated from carbon steel. Packing shall be Teflon lubricated synthetic packing. Packing gland bolts and studs shall be 304 stainless steel.
The valve yoke shall be fabricated carbon steel. The valve stem shall be 304 stainless steel with full ACME threads. The stem nut shall be bronze. The stem nut retainer shall be of the enclosed type and shall be carbon steel.
Manually actuated valves shall be bevel gear operated.
Valves shall be designed, manufactured and tested to comply with MSS SP-81, Standard Practice for "STAINLESS STEEL, BONNETLESS, FLANGED,WAFER,KNIFE GATE VALVES".
Valves shall be Fig 76 knife gate valve (Metal seat), Fig 77 knife gate valve (Resilent seat) or approved equal.
BONNETED KNIFE GATE VALVE (2"-24")
Valves shall be of the bonneted knife gate valve type, rated for 150 PSI CWP. Flanges shall be drilled and tapped to ANSI B16.5, 150 pound standard with raised faces. Flange raised face machining shall be serrated-spiral or serrated-concentric grooves with a 125-250 RMS finish. Valve bodies shall be cast 304/316 stainless steel (CF8/CF8M) with a metal seat. Valve face to face shall be in accordance with MSS SP-81.
The valve bonnet shall be fabricated with 304/316 stainless steel liner, packing box and bonnet flange raised face. Bonnet flange and stiffeners shall be carbon steel (or optional 304 stainless steel).
A gate wiper shall be used between the bonnet and the body flanges. The wiper material shall be UHMWPE.
Packing shall be adjustment free using Viton and Teflon O-ring seals around the stem. As an option, Teflon lubricated synthetic compression packing may be used. Packing gland bolts and studs shall be 304 stainless steel.
The valve yoke shall be cast 304 stainless steel (CF8). The valve yoke shall be the flat top design to allow bolt-on field installation for conversion of actuators without welding or machining of the yoke. The wetted valve stem shall be 304/316 stainless steel. The threaded portion of the stem shall have full ACME threads. The lifter shall be cast 304/316 stainless steel (CF8/CF8M), welded to the stem and be a two horizontal bolt design. The stem nut shall be bronze. The stem nut retainer shall be of the enclosed type and shall be cast 304 stainless steel (CF8).
Manual actuated valves shall be handwheel operated. Bevel gear operators are recommended for valves 16" and above where frequent operation is required and/or where used in applications above 75 PSI.
Valves shall be designed, manufactured and tested in accordance with MSS SP-81, Standard Practice for "STAINLESS STEEL, BONNETLESS, FLANGED,WAFER,KNIFE GATE VALVES".
All valves shall be Figure 176 Knife Gate Valve or approved equal.