RAYS Through Conduit (T.C.) Slab Gate Valves are manufactured with a full bore port, rising stem OS&Y and with floating seats and gate, pressure energized, for a bubble tight shut off upstream and downstream under both low and high differential pressure. Double block and bleed capability and automatic relief of excess body pressure are a standard feature of this seat design. The smooth, continuous bore minimizes turbulence within the valve and when in the open position it produces a pressure drop equivalent to a portion of pipe of the same length and diameter. The seat faces are outside the flow stream and therefore protected from the erosive action of the flow. Pigs and scrapers can be run through the valve without damage.
PRODUCTION RANGE FEATURES
Slab Gate Valves are available in sizes and pressure ratings as follows:
•Class 150# from 2″ through 64″
•Class 300# from 2″ through 64″
•Class 600# from 2″ through 64″
•Class 900# from 2″ through 48″
•Class 1500# from 2″ through 42″
•Class 2500# from 2″ through 24″
Slab Gate valves comply with API 6D / API 6D SS and all relevant international codes:
•ASME VIII Div. 1
RAYS Through Conduit (T.C.) Slab Gate valves are manufactured using a wide range of materials, from carbon steel to alloys.
A typical material selection is as follows:
|General non corrosive||Body||Bonnet||Trim||Seat Insert|
|Moderate corrosive||A216 WCB||A105||A105 + ENP||Nylon/RPTFE|
|Service||A352 LCC||LF2||LF2 + ENP||Nylon/RPTFE|
Features of Through Conduit Slab Gate valve
•Negligible Pressure Drop
•Self – Relieving
•Double Block and Bleed performances
•Equalized Bore (as required/operated)
•Possibility of reverse acting and
equalized bore for fail closed operation
•Double seal upstream by piston effect, down-stream with floating obturator
•Superior Seal Per formances (Bubble Tight)
•Suitable for all types of fluids (including abrasive fluids)
•Suitable for ESDV/BDV applications and Pig Traps
•Extremely flexible actuation with or without stem ejection assistance
•Full In-Line maintainability
•Fire Safe construction
The stem is designed with a threaded-in T bar allowing relative motions of the gate under line pressure. The stem seal uses braided graphite gaskets ensure sealing integrity. Stem sealant injection system is achieved through a por t located on the bonnet. In case of leakage through the stem seal it is possible to inject the sealant through the stem packing release valve.
Seats are ENP coated and are provided with thermoplastic soft inser t on their face.
A “double face seal” effect is obtained due to metallic contact between the seat and the gate, thus increasing the reliability of the valve. Metal-to-metal seating is available for abrasive ser vice. In such case gate and seat faces are coated with HVOF Tungsten Carbide coating.
RAYS Through Conduit Slab Gate valve is available in the API 6FA fire-tested design. Fire-tests have been witnessed and cer tified by independent authorities. RAYS Fire tested gate valves offer the highest resistance against fire. The body seal is a spiral wound graphite/AISI 316 gasket and the stem seal is a die-formed/braided graphite packing. The stem incorporates the back seat feature to allow stem seal re-packing with valve in ser vice. Fire-tests cer tification is available and can be provided upon request.
RAYS Through Conduit Slab Gate Valves are designed to be Fully Piggable. Pigs and scrapers can be run through the valve without any damage to the internal structure of the valve.
RAYS Srl Through Conduit Slab Gate valve design minimizes and eases the maintenance allowing for the ser vice operations to be done without the removal of the valve from the line.
Double Block and Bleed
Double block and bleed capability and automatic relief of excess body pressure are standard features of RAYS Through Conduit Slab Gate Valves. With the valve fully closed and pressure on both sides, it is possible to bleed the pressure from the body cavity to check seat seal integrity and to achieve double isolation between the two sides and avoid any risk of product contamination
Single piston effect seats
Seats rings are floating type and are energized against the gate by means of helical springs. The initial seating is enough to assure sealing between gate and upstream seat when the line pressure is applied. The gate allows axial movement and the upstream force derived from line pressure force the gate against the downstream seat creating a double, bubble tight barrier.
Additional features (Available on request)
• Metal seated/Tungsten Carbide coating for abrasive fluids
• Stem extension for buried ser vice/high temperature ser vice
• Inconel 625 cladding of the sealing sur faces for corrosive ser vice
• CRA alloys for ver y corrosive media (Duplex,UNS S31254,UNS S34565)
• Seat Sealant Injection system for Emergency Sealing
• Transition Pipe Pups welded to the valve ends
• Position indicator
• Actuation (Electric, Pneumatic and Hydraulic actuators)
Self relieving features
The single piston design with the possibility of both seats and gate to float, permits the automatic release of any overpressure in the body cavity.
Consequently, the seat rings are “self-relieving”.