GATE VALVES DEFINITION BASIC AND TUTORIALS

A gate valve is a multiturn valve in which the port is closed by a flat-faced vertical disk that slides at right angles over the seat.


Recommended
● For fully open or fully closed, nonthrottling service
● For infrequent operation
● For minimum resistance to flow
● For minimum amounts of fluid trapped in line
Applications

● General service, oil, gas, air, slurries, heavy liquids, steam,
noncondensing gases and liquids, corrosive liquids

Advantages
● High capacity
● Tight shutoff
● Low cost
● Simple design and operation
● Little resistance to flow

Disadvantages
● Poor flow control
● High operating force
● Cavitates at low pressure drop
● Must be kept in fully open or fully closed position
● Throttling position will erode seat and disk
● Body cavity pressure lock on certain designs

Variations
● Gate: solid wedge, flexible wedge, split wedge, double disk, slab, expanding slab, through
conduit
● Stem: standard, packing, outside screw and yoke

Materials
● Body: bronze, iron, ductile iron, carbon steel, low-alloy steel, stainless steel, Monel, nickel
alloys, PVC plastic
● Trim: various

Special Installation and Maintenance Instructions
● Lubricate on regular schedule.
● Correct packing leaks immediately.
● Always cool system when closing down a hot line and checking closed valves.
● Never force valves closed with wrench or pry.
● Open valves slowly to prevent hydraulic shock in line.
● Close valves slowly to help flush trapped sediment and dirt.

Ordering Specifications
● Type of end connections
● Type of wedge or gate
● Type of seat
● Type of stem assembly
● Type of bonnet assembly
● Type of stem packing
● Pressure rating: operating and design
● Temperature rating: operating and design

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1 comment:

Elizabeth J. Neal said...

A wide selection of NIBCO ball valves are available in bronze, brass, lead-free, carbon steel or stainless steel materials. Anix Valve

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