Comparison Slab Gate Valve vs Wedge Gate Valve

Slab gate valve and wedge gate valbe are the main type of gate valves that are designed for full opening or full closing service. They are installed in pipelines as isolation valves and should not be used as control or regulating valves. Gate valves are operated by a rotational movement of the stem clockwise closed (CTC) or clockwise open (CTO). When the stem is operated, the gate moves up or down on the threaded portion of the stem.

Slab gate valves

Slab gate valves have a parallel slab gate on either side of a floating seat. Sealing is provided by a pressure differential. The design ofslab gate valve is always straight through. The design is suitable for a wide range of applications, such as wellhead isolation, process piping, water tanks, etc .

Specifications Of Slab Gate Valve that you should know

(Specifications Of Slab Gate Valve that you should know)

• Low operating torque

• API Spec 6A PSL 1,2,3

• Forged body and engine cover

• Simple design ensures low cost

• Maximize valve life

• Material Class DD, EE. FF, to NACE MR-01-75

• Two-way MVTLS-B flat gate valve for high pressure

• Metal to metal seal (gate to valve seat, valve seat to body and valve body to bonnet)

• Can provide flange type, stud type, weld neck type, threaded type outlet

• Regardless of the gate location, the metal-to-metal back seal can be energized

• The gate guide retains the body lubricant and protects the gate surface

• Critical applications from 3000 psi to 15000 psi pressure

Wedge Gate Valves

Wedge discs are used to introduce a high supplemental seat load, allowing metal-seated wedge gate valves to seal not only at high fluid pressures, but also at low fluid pressures. Both solid wedge gates and flexible gates are available. One-piece solid wedges are used because they are easy to fabricate. Flexible wedges are grooved to make them sit more easily on the seat surface. Standard steel wedge gate valves should normally be specified with a male thread and yoke, rising stem, non-rising handwheel, and bolted bonnet. Wedge gate valves do not shut off high pressure gases as effectively as slab gate valves or expansion gate valves, so the latter should be specified in these cases. When ordering, we must specify to the supplier whether the seal is downstream only or upstream & downstream. 

Different Applications- Slab Gate Valve vs Wedge Gate Valve

• Slab gate valves application

Ingle or double-disc slab gate valves are suitable for oil and gas pipelines with DN50-DN300, class 150-900/ PN1.0-16.0 Mpa, 3000 psi to 15000 psi on wellheads, operating temperature -29~121 . In the case of pipeline with piggable design, use a rising stem gate valve with a diversion hole. The slab gate valve with a diversion hole with a dark rod floating seat is suitable for oil and gas recovery wellhead device. The product oil pipeline and storage equipment shall use a single gate or double gate flat gate valves without diversion holes.

• Wedge Gate Valves application

Wedge gate valves are generally used where has no strict requirements of the size of the valve and harsh occasion. Such as high temperature and high pressure working medium, the requirements to ensure the closure of the long-term sealing conditions. Normally, for the environment with reliable sealed performance, high pressure, high-pressure cut-off (differential pressure) and low pressure by the (small) differential pressure, low noise, have spirit point and evaporation phenomena, the high temperature, low temperature, cryogenic medium, it is recommended to use wedge gate valve such as the electric power industry, oil refining, petrochemical, offshore oil, tap water and wastewater treatment engineering of urban construction, chemical industry, etc . 

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