Gate Valves - API 600

A gate valve, occasionally known as a sluice valve, is a valve that opens by lifting a gate (closure member / disc) out of the path of the fluid which could be liquid or gas. Gate valves requires very little space along the pipe axis and hardly restrict the flow of fluid when the gate is in fully open position. The gate faces can be parallel but however are most commonly wedge-shape with small angle with the vertical axis (in order to be able to apply pressure on the seating surface). In general, Gate valves are designed as per API 600 and API 602 standards.

Function

Gate valves are widely used to shut off the flow of liquids rather than for flow control (regulation), which is generally done with a globe valve. When fully open, the typical gate valve has no obstruction in the flow path, thus resulting in very low flow resistance. The size of the open flow path generally varies in a nonlinear manner as the gate is moved. This means that the flow rate does not change evenly with stem travel. Depending on the construction, a partially open gate can vibrate from the fluid flow.

Operation

Common gate valves are actuated by a threaded stem that connects the actuator (e.g. handwheel or motor) to the wedge (gate). They are therefore characterized as having either a rising or a non-rising stem, depending on which end of the stem is threaded. Rising stems are fixed to the gate and rise and lower together as the valve is operated, providing a visual indication of valve position. The actuator is attached to a nut that is rotated around the threaded stem to move it.

Non-rising stem valves are fixed to, and rotate with, the actuator, and are threaded into the gate. They may have a pointer threaded onto the stem to indicate valve position, since the gate's motion is concealed inside the valve. Non-rising stems are used where vertical space is limited. Gate valves may have flanges ends drilled according to pipeline-compatible flange dimensional standards. Sometimes gate valves are butt welded on pipelines. Gate valves are typically constructed from cast iron, cast carbon steel, ductile iron, gunmetal, stainless steel, alloy steels, and forged steels. All-metal gate valves are used in ultra-high vacuum chambers to isolate regions of the chamber.

cast steel valve

Construction as per API 600 & API 602

Bolted Bonnet & Welded Bonnet

Bolted Bonnets provide leak-proof enclosure for the valve body. Gate valves may generally have a screw-in, union, or bolted bonnet. A screw-in bonnet is the simplest, offering a durable, pressure-tight seal and are used for smaller sizes normally. A union bonnet is suitable for applications requiring frequent inspection and cleaning. It also gives the body added strength. A bolted bonnet is used for larger valves and higher pressure applications. Bolted bonnet is widely used for sizes 2 inch and above. Occasionally welded bonnet is used where the valves are buried or zero leak at longer service duration are required.

Pressure seal bonnet

Another type of bonnet construction in a gate valve is pressure seal bonnet. This construction is adopted for valves for high pressure service, typically in excess of 2250 psi (15 MPa). The unique feature of the pressure seal bonnet is that the bonnet ends in a downward-facing cup that fits inside the body of the valve. As the internal pressure in the valve increases, the sides of the cup are forced outward. improving the body-bonnet seal. Other constructions where the seal is provided by external clamping pressure tend to create leaks in the body-bonnet joint.

Applications

Industrial applications such as oil and gas, petrochemicals, chemical, power generation, mining and industries use this valves. What makes this useful is that the design limits flow obstruction. Additionally, there is also a minimal pressure drop. This valves are also used in fire fighting applications with some minor changes in design standard and material specifications.

Why Select and Use Flowtorq Gate Valves ?

Easy Availability
Economic Cost
Wide Range of Size from 1/2" (half inch) to 32" and above
Wide Range of pressure rating capacity from 150# low pressure to 2500# high pressure and above
Easy Operation
Easy Maintenance and handling
Available in Stock and shorter lead times
Rigid and Robust Construction
Wide Variety of internal trim parts variants
Long Service Life
ON-OFF Duty only

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gate valve

General Technical Specifications

Size Range – 1/2″ to 36″
Pressure Rating – 150#, 300#, 600#, 800#, 900#, 1500#
Certifications – IBR, CE, etc.
Inspected & Witnessed By third party agencies
API Valves, ATex Valves, CE Valves, Process Valves, Gas Valves, Water Valves, Cryogenic Service, Fire Safe