Van cửa Slab hiệu Zeco (Slab Gate Valve)

Description

Slab through conduit gate valves are designed and manufactured in accordance with API 6D and API 6A standards and specifically for on-off services. This valve is suited to withstand all types of process fluids, under high pressure and temperature conditions

What is a Slab Gate Valve?

Slab gate valves are full-port valves, which means the hole in the gate is exactly the same size as the pipe. This full port design provides full flow through the valve and low-pressure drop, and it allows for pigging the line when needed.

The flow characteristics of ZECO slab gate valve with diversion holes are the same as those of the pipeline of the same diameter. Compared with the other two kinds of valves, the flow characteristics of the adjustment type slab gate valve without a diversion hole are better than those of the ordinary type without a diversion hole. Therefore, in the long pipeline, natural gas, oil industry, slab gate valve with diversion hole is particularly widely used. ZECO Valve Group, a well-known manufacturer of slab gate valves in China, can deliver large-scale, excellent quality, and exquisite appearance slab gate valves in full accordance with API 6D standards.

Specifications of Slab Gate Valves

Sealing of Slab Gate Valves

• Body Sealing
  • All primary body gaskets are metal-to-metal, spiral wounds, or ring-type joints.
  • Available upon request:
    • Secondary soft gasket to introduce a redundant barrier
    • Leak port detector

• Stem Sealing
  • PTFE Chevron Type: Thermoplastic multiple V-rings, with or without lantern ring.
  • Available upon request:
    • O-ring sealing
    • Graphite sealing
    • Metal-to-metal stem seals in addition to the standard thermoplastic seals
    • Sealant injection capability (optional)
    • Redundant elastomeric (AED ) stem gasket
    • Leak port detector

• Seat Sealing
  • ZECO Slab gate valve construction includes spring energized floating seats, which provide positive seating on both sides, regardless of upstream or downstream pressure conditions. The seat seals are spring energized to ensure sealing under low-pressure conditions. When the line pressure increases, the seat-to-gate contact pressure increases accordingly to provide a positive shutoff. Since both seats are individually energized by differential pressure across the seat itself, the valve cavity can be vented when the upstream and/or downstream side is pressurized. The valve exhibits identical performance, regardless of the direction of flow, and /or orientation of differential pressure.

Features of Slab Gate Valves

• Slab gate valves are comprised of a single gate unit that raises and lowers between two seat rings. Due to the fact that the gate slides between the seats, slab gate valves are suitable for the medium with suspended particles. The sealing surface of slab gate valves is virtually self-positioned and is not damaged by the thermal deformation of the body. Even if the valve is closed in a cold state, the hot elongation of the stem does not overload the sealing surface, and slab gate valves without diversion holes do not require high precision in the closing position of the gate. When the valve is fully open, the bore through is smooth and linear, and the flow resistance coefficient is minimal, peggable, and no pressure loss.
• ZECO slab gate valve is equipped with a grease injection hole, in case of sealing surface damage, the maintenance personnel can easily inject sealant through the grease injection hole to maintain the sealing surface to ensure the normal switching performance of the valve or in the case of maintenance, provide injection sealant to lubricate the sealing surface to extend the normal service life of the valve;
• When ZECO slab gate valve is fully open, the channel is the straight pipeline, the flow resistance coefficient and pressure loss are very small and almost negligible, which can reduce the cost of pipeline operation for users, and the pills can be used for cleaning when cleaning the pipeline;
• ZECO slab gate valve is equipped with an automatic pressure relief protection device, which can automatically relieve pressure in the case of overpressure in the middle chamber of the valve body to protect the safe use of the valve;
• The floating seat structure of ZECO slab gate valve ensures that the valve can be sealed in both directions.

Disadvantages of Slab Gate Valve

Slab gate valves also have some disadvantages: when the medium pressure is low, the metal sealing surface may not seal completely, instead, when the medium pressure is too high, the highly-frequency opening and closing may make the sealing surface wear too much when there is no medium or lubrication. Another drawback is that a circular gate that moves horizontally on a circular channel controls flow effectively only when it is at 50% of the valve’s closed position.

Material of Through Conduit Gate Valves