Wellhead Gate Valves

Quality Systems

Unimech Oil &
Gas wellhead gate valve products feature a full bore/thru-conduit design, in-line repairability and protected long-life seats. Our gate valves are designed for all types of applications including wellhead, christmas tree, ESD, and choke and kill manifold systems. Our models can be equipped with single or double-acting hydraulic or pneumatic actuators with manual override and fail-safe closed or open systems.

Proprietary CRA

Our castable corrosion resistant alloy SCR 6191 can be substituted for solid Inconel™ type material and/or alloy-type clad valves for extremely severe and corrosive environments.

Parallel Expanding

This unidirectional expanding gate gives an extraordinarily high mechanical seating seal force that acts simultaneously against both seats. The seating force is not affected by line pressure fluctuations or vibrations.

Dual Segmented

For sweet service wellheads, Hills Flow Control, Inc offers dual segmented gate valves. The body casting has a recess to allow passage of the conduit of the other gate valve.

Solid Slab

This design is made for demanding applications including high pressure critical service choke and kill manifolds, and for use as a safety shut-off valve operated by a hydraulic or pneumatic actuator. It incorporates a bidirectional design with a floating gate that moves parallel to the seats and effects a tight seal under differential line pressure. The nonrising stem has a backseating feature which allows the stem bearings or packing to be replaced under pressure.


This bidirectional valve features a metal-to-metal seal between gates and seats, and seats to body. Sealing is enhanced by an auto-seal system whereby internal body pressure transmits sealing compound from reservoirs in the seats to grooves around the seat bore, thereby preventing leaks. The parallel nonwedging gates allow the stem to be left unstressed in either the open or closed position. Fully skirted seats provide continuous protection of gate sealing surfaces. A backseating feature allows replacement of stem bearings or packing under pressure.

Composite Block

A composite block valve has integral bodies that include studded side outlets for flanged wing valves or other equipment. They are available as single, dual or triple completions with single or double master valves. In addition, integral swab valves or wing valves with 45° ‘Y’ studded side outlets may be provided.

High Temperature

Being one of the pioneers in SAGD (Steam Assisted Gravity Drainage) equipment and other thermal applications, Hills Flow Control, Inc offers various gate valve options for high temperature service such as steam injection and heavy oil production. These valves are designed for operating temperature to 650°F (345°C).

Other End Connections (Threaded)

Gate valve end connections are available as threaded, clamp-hub or union connection in addition to the more common flanged end.