Top Entry Ball Valves
CAST OR FORGED STEEL, TOP ENTRY, TRUNNION MOUNTED BALL, SPRING ENERGIZED SELF RELIEVING SEATS, SOFT OR METAL SEATED, ANTI BLOW-OUT STEM, ANTISTATIC DEVICE, FIRESAFE DESIGN
BODY
One-piece body, cast or forged in carbon, stainless and other CRA steels commonly used in the O&G industry such as Duplex, Super Duplex and Nickel Alloys . Its design is in compliance with the relevant API and ASME Standards. Threaded plugged connections are provided for the vent and drain functions.
SEAT RINGS
Floating, renewable metallic rings are supplied as a standard with a soft thermoplastic insert that provides a Zero Leakage seal. Insert material is selected based on valve pressure/temperature design conditions. Springs keep the seats pushed against the ball to ensure a tight seal at low pressure and allow the same to slide back to release any overpressure in the body cavity (Single Piston Effect). In some instances seat rings can be required to effect a double seal – from the line as well as from the body cavity – (Double Piston Effect). In this case a relief valve may be required to release the cavity overpressure. For special services (slurry, presence of solids, high temperature) the soft insert can be replaced by a hard facing with Tungsten or Chrome Carbides Coating (Metal Seated).
BALL
The ball is normally supported and guided by an integrally machined trunnion or an additional plate fixed to the body. It makes a 90° movement from the fully open to the fully closed position driven by the stem connected to a slot in the ball. Its circular opening allows for minimal pressure losses and, in Full Bore execution, for the passage of inspection/cleaning devices (Piggable). In metal seated execution the sealing area of the ball is also coated with Tungsten or Chrome Carbides and lapped with the seats to obtain a tight sealing.
STEM
The stem is designed to comply with relevant API Standard requirements. It is inserted from inside the bonnet through the gland and the adapter plate to connect with the operator and its shouldered design ensures that it cannot be ejected by the internal pressure (Anti Blow-Out). It houses the stem sealings, either elastomeric O-Rings or thermoplastic Lip Seals, designed to meet the most stringent Fugitive Emissions requirements. A Graphite ring integrates the set of sealings as a Firesafe barrier.
BONNET
The bonnet is bolted to the body by means of fully threaded studs and nuts. The peculiar design of the Top Entry valve allows direct access to the internal parts by disassembling the bonnet, without having to remove the valve from the line as in a Side Entry design.
ADAPTER PLATE
The adapter plate is the upper flange for connection to the operator, either Gear or any type of Actuator. It is designed and sized in accordance with ISO 5211.
BODY BOLTING
Body studs and nuts are supplied in materials according to ASTM standard and can be coated to any special requirement. The body to bonnet connection is designed according to ASME VIII Div. 1
OPTIONALS
Stem and/or Seats Sealant Injection System can be provided upon request