KITZ has three type of Trunnion mounted ball valves.
Soft Seated 3-piece body Trunnion Mounted Ball Valve (T-60S series)
Metal Seated 3-piece body Trunnion Mounted Ball Valve (T-60M series)
Soft Seated 3-piece body Trunnion Mounted Ball Valve (F18TK-T60 series, made in Spain)
(1) Internal Leakage Prevention
When resilient sealing materials are damaged or destroyed by a plant fire, edges of upstream and downstream metal seat retainers preloaded by seat springs come into contact with the ball to shut off line fluid to minimize internal leakage through the valve bore. And, flexible graphite seat retainer packing rings of KITZ original design prevent fluid leakage from between the valve caps and seat retainers during and after the plant fire.
(2) External Leakage Prevention
External leakage from the valve stem area is prevented by double sealing with O-rings and flexible graphite gland packing rings. Leakage through the valve body joint is protected by flexible graphite gaskets. Even after a fire has deteriorated O-rings, flexible graphite gland packing rings and gaskets remain intact to prevent external fluid leakage.
The resilient seat design adequately maintains each of the upstream and downstream ball seats in contact with the ball by means of repulsing force of seat springs inserted behind the seat retainers. Line fluid pressure also helps this contact method. This sealing mechanism features unfailing thru-the-bore sealing performance of upstream and downstream side ball seats at the same time.
Ball seats independently shut off the line fluid on the upstream and downstream side of the ball. The valve bore and the body cavity are isolated from each other when the valve is fully pressure can be discharged with a vent valve and a drain plug.
The vent valve is equipped with a blowout-proof bleeder for safe discharge. Relieving the cavity pressure with a vent valve is recommended for safe draining.
As illustrated below, ball seats are threaded into unthreaded back of seat retainers to finally reach to inner walls and lower shoulders of the seat retainers for tightly sealing surface-to-surface contact.
This unique design provides easy maintenance and blowout-proof seat assembly when ball seats are excessively loaded by back pressure due to incidental cavity pressure rise.
Spring loaded balls assembled between the stem and the bonnet and between the stem and the ball permits electric conductivity through all metallic valve components.
In case of incidental rise of servicing or ambient temperature, liquefied gas or highly volatile liquid trapped within the body cavity may vaporize, and cause an excessive rise in the cavity pressure. For safety consideration, when the cavity pressure exceeds the line pressure, either one of the ball seats will move
slightly away from the ball surface together with seat retainers to relieve the excessive cavity pressure into the valve bore.
The fugitive emission suppressing design for both resilient and metal seated valves are certified to ISO 15848 tightness class “B” (Lower than 10-4 mg·s-1 ·m-1 for stem leakage and lower than 50 ppmv for body leakage). This verifies the outstanding low emission performance of the whole sealing mechanism of the valve.
(1) Emergency Seal Restoration*2
For accidental leakage from ball seats or stem sealing area, a sealant supply mechanism may be provided as an option.
Should sealing parts be damaged or decomposed by a fire or other accidental causes, leakage can be temporarily prevented or reduced by sealant injection into this mechanism.
(2) Special Shell and Trim Materials
(3) Special Sealing Component Materials
(4) Butt-weld Piping Connection
(5) Pipe Pups Welded to Valve Ends
(6) DIB: Double Isolation and Bleed (Double Seal)*3
(7) Stem Extension
(8) Overlay for Bore and Cavity
(9) Actuation (Pneumatic and Electric)
*1 For all optional provisions, please contact your local KITZ agents or distributors.
*2 Standard design for North America.
*3 Any combination of DPE (Double Piston Effect)/SPE (Single Piston Effect) is available.