Fully Welded Ball Valve

● DESIGN FEATURE OF FULLY WELDED BALL VALVE

● Double Block and Bleed

The flow can be complete blocked when valve is at full close position. At the full close and full open position, the deposition contamination or media in valve body cavity can be bled also. And if contamination is bled regularly, the damage from contamination to valve sealing surface can be reduced and valve service life can be extended.

Double Block: Trunnion Ball Valves are made with pre-loading spring floating seat rings, the service flow can be fully blocked by upstream and downstream seat rings no matter valve is in fully open or fully close position.

Double Bleed: If the pressure of the body cavity unusually rises up, the trunnion valve can automatically relieve the pressure by compressing springs in the spring pre-tighting seat package. It is very important for the valve safety during transporting the liquid medium. 

● Full Bore or Reduced Bore

Full bore or reduced bore is chose upon request. Port dimension of full bore size can satisfy the requirement of API 6D standard, low flow resistance, suitable for piggable. 

● Anti-static Design

Electrical conductivity between metal parts, such as body, ball, seat retainer, stem, etc. isolated by rubber or plastic sealing parts, can be guaranteed by stainless steel springs per BS5351.

● Ball without Pressure Balance Hole

No balance hole in ball to balance body cavity pressure when opening valves, so medium in body cavity can be drained when valve is in full close or full open position. Customer can make effective check or maintenance without change operation conditions.

● Stem Anti-flying Away Design

Stem is separated from valve ball and designed per ASME B16.34 and BS 5351 for Anti-flying away. There is an integral shaft shoulder pressed under self-lubricating thrust bearing.

● Dual Sealing Seats

Each seat retainer is independent and floating, and is designed to cut off medium by inner pressure automatic sealing (Double Piston Effect). So the valve is bi-directional dual sealing type valve and can assure downstream’s seal when upstream seal failed.

● Stem Dual Sealing

Stem dual sealing can be realized by two pcs of O-ring made of PTFE, and outer O-ring can be replaced under pressure.

● Emergency Sealing

If seals for stem and seat retainer is damaged, sealant can be used for temporary repair. We design sealant injection holes in bonnet or cap and bonnet to prevent leakage due to damage of seals for stem and / or seat retainer. Sealant injection holes and grooves can distribute sealant. We also design one non-return valve with an instantaneous connection to injection kit in each sealant injection hole.

● Fire Proof Design

All standard design for valves is complied with API607/API 6FA/BS 6755：PART

● Drain Connection

Each valve has drain connection and vent connection for plug or valve.

● Stem Extension

For valves under ground or buried, stem can be extended. And vent valve, drain valve and sealant injection can also be extended to suitable position.

● Main Standards:

 Holy welded ball valve is available in both of butt welding ends and flanged ends.

● Material of parts