After many years of development and testing, Balon patented and introduced a ball valve that represented a dramatic turning point in valve safety. It was the first ball valve with the following:
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Backseated stem to prevent stem blowout
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Packless stem gland housing which eliminates stem adjustment mechanisms
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Stem shear groove to assure controlled stem damage above the backseat
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Full Metal spectrum fire safety for metal-to-metal secondary sealing at all potential leak points
Balon then encased these safety improvements in a rugged bolted body assembly capable of withstanding violent thrust loading and line stresses so common in high-pressure line applications.
Fire safety in ball valves has become a major consideration as more and more ball valves have been used in hazardous environments.
The Balon Ball Valve has been designed to provide maximum backup sealing in the event resilient seals are destroyed by heat or fire.
Controlled Spacing
The interior components of the valve, with seals intact, can be seen in Figure "A". In the closed position the ball is held off of the secondary metal seat position.
The seat and seat pocket are made oversized in radial dimension, allowing close spacing of the ball and metal seat provision. In operation, with prime seals in place, this controlled spacing prevents damage to the surface finish of the ball.
It can also be seen that the stem is back-seated, and with seals in place the primary stem seal holds the stem off of the metal shoulder machined in the valve body.
Secondary Stem Seal
In figure "B", the seals have been fully dissipated, the ball has moved downstream onto the secondary metal seat, and the stem has been checked, metal-to-metal, against the inner shoulder.
As can be seen, the stem is free to move upward when subjected to a slight amount of pressure, onto the machined metal inner shoulder, thus substantially restricting any flow past the stem into the atmosphere.
Straight Ahead Ball Movement
The stem tongue is keyed into a linear milled slot, straight and perpendicular to the bore of the valve. In the closed position, the ball is free to move downstream onto the secondary metal seating, functioning at that moment as a simple ball check valve.
The ball itself is confined in the body with just enough vertical and horizontal clearance to assure free and easy operation. This keeps the ball in uniform alignment so that ball movement onto backseating - should it become necessary - is consistently on a straight course, without deflection up, down or sideways.
The valve may be positioned in either vertical or horizontal installations, and retain its secondary metal-to-metal sealing capability.
These very simple provisions are intended to provide full operational safety in our valves. Every attempt has been made in our design to produce a valve that is safe and affordable.
Balon Ball Valves have been successfully tested by an independent laboratory in accordance with API Standard 6FA "Fire Test for Resilient Seated Ball Valves". Results of this testing are available on request from Balon's headquarters.
