Ball Valves Standard Features:

• Double Block and Bleed:

The fluid entrapped in the valves body is bleedable with the ball in fully closed position to API Spec 6D provisions.

• Valves Bore:

Valves are of full or reduced bore design. Reduced bore is of Venturi type. Minimum bore size is to API 6D requirements.

• Body Structure:

The manufacture of the body is of three types: split-body or welded-body or top-entry. The split or welded body design is used for valves side-entry type. It consists of three forged steel pieces joined by bolting or welding respectively. The body of valves top-entry type is made of one cast steel piece.

• Antistatic Design:

Stainless steel springs ensure the electrical continuity between all the valves metal parts (e.g. body, ball, seat rings and stem) which could be isolated by electrometric or thermoplastic seals.

• Pressure unbalanced ball:

Unless otherwise requested, no hole is provided for the ball to equalize the pressure of the fluid in the pipeline to the one of fluid entrapped in the body cavity when the valves is open. It enables a preventive maintenance, allowing the check of the ball seating efficiency in any valves position, with no modification of the pipeline working condition.

• Anti-blowout stem design:

The stem, detachable from the bal, is blow proofed thanks to an integral abutment resting against the bonnet through a self-lubricating thrust washer.

• Bi-directional seat rings:

Each seat ring is independent floating type and suitably designed to shutoff the fluid aside from its pressure distribution through the valves. So both seat rings constitute a double barrier to the fluid, because of the downstream seat ring ensures shutoff of the fluid in case the upstream one fails. As any overpressure of the fluid entrapped in the valves body cannot be released back into the pipeline, a relief valves is fitted to the vent connection if the handled fluid is a liquid.

• Ball seating:

Valves with rating lower than ANSI Class 1500# have a seat insert made of elastomer to enable double ball sealing: a primary of metal-to-metal and a secondary of soft type (Fig.a). Valves with higher rating are provided with a seat insert made of thermoplastic resin (like Nylon or filled PTFE) to ensure a soft bubble-tight only against the ball (Fig.b). In addition, a double plastic+elastomer seal is recommended for valves having a stainless steel trim with no plating to be used in very low pressure service (Fig.c).

• Double Seal of stem:

Two elastomeric O-rings provided with backup in PTFE perform a double stem barrier to the fluid. The outer O-ring can be replaced with the valves under pressure.

กก