Flow Control Choke Valve Stem And Seat Flow Control System With Stable Chemical Properties

Valve is assembled product. Valve external parts and Valve trim parts such as Body, Bonnet, Disk/wedge, Seat, Steam, Gland Packing / Stud & Bolt

/ Gasket / Handwheel are all manufactured independently and assembled in valve factory.

Tungsten Carbide Materials Grade As Below:

What is Valve Trim?

The removable and replaceable internal parts of the valve that come in contact with the flow medium are collectively known as valve trim. Disc, valve seat, and stem are common for all the valve. Valve Trim components will change with types of valve. Valve specific trim includes back seat, glands, spacers, guides, bushings, retaining pins and internal springs. Here in the image, you can see the gate valve trim parts. Because of the trim parts, disk movement and flow control are possible.

Seat

The seat provides the seating surface for the disk. Here, you can see the gate valve seat in the above image. A valve may have multiple seats. In the case of globe valve and swing-check valve, there is one seat. Whereas, a gate valve and ball valve has two seats; one on the upstream side and the other on the downstream side.

The valve leakage rate is directly proportional to the effectiveness of the seal between the valve disc and seat(s). Valve seats may be integral or replaceable rings. Valves are generally provided with screwed, welded, or integrally cast or forged seat and hardened by heat treatment or by hard facing of Stellite weld overlay. A fine surface finish of the seating area is necessary for proper sealing. Some ball valve & plug valve used the non-metallic seat for non-critical services. Valve manufacturers have developed several designs of combination valve seats involving elastomer and metal seats that are effective in achieving the desired leak tightness, which cannot be achieved only by metal seats.

Stem

The stem connects the actuator and disk. It moves and positions the valve disk. The valve stem transports the required motion to the disc, plug, or the ball for opening, closing or positioning the valve. The stem connects actuator, handwheel or the lever of the valve at one end and the disc on the other end. In gate and globe valves, linear motion of the disc open or close the valve, while in the plug, ball, and butterfly valves, the disc rotates to open or shut the valve. Stems are typically forged from stainless steel and connected to the disk by threaded or welded joints.

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