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Gate, Globe & Check Valves
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Deterioration of water quality and changes in piping materials have amplified valve dezincification problems.
The copper alloy used in bronze valves contains zinc, tin, and small amounts of lead with copper as a base. When bronze valves are subjected to unfavorable operating conditions the zinc component contained in the copper alloy separates from the copper base, and the metal corrodes. This is called dezincification. In a bronze valve, the body, bonnet, and other bronze cast parts hardly corrode at all due to the small percentage of zinc in bronze alloy B-62. Brass parts with a 40% zinc content (stems in particular) are subject to extreme dezincification. Watts MSS-SP rated bronze valves have stems made from dezincification-resistant bronze alloy B-62.
Why Does Dezincification Occur?
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The following factors cause dezincification. These factors are generally believed to occur together, rather than independently.
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Aqueous solutions high in acidity.
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Warm water with a high free carbonic acid content and high electrical conductivity.
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High electrical conductivity with large quantities of chlorides and sulfides present.
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With copper or vinyl chloride pipes.
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With a large quantity of dissolved oxygen. |
Dezincification can occur in bronze valves when the stem is made from a brass alloy containing a high percentage of zinc. Watts MSS-SP rated bronze gate and globe valves are supplied with stems made from Bronze Alloy B-62. Bronze Alloy B-62 stems offer superior resistance to dezincification as well as superior tensile strength, hardness, and corrosion resistance when compared to brass alloy stems. This attention to detail explains why Watts valves provide excellent performance and longer service life. You can depend on Watts quality valves to resist dezincification. |
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Watts Bronze Valves are built on fully automated molding and machining lines. This highly automated process achieves consistent precision in manufacturing Commercial and Industrial valves for water, oil, gas and steam services. More than a promise of excellent performance, they deliver the needed efficiency for all around problem-free flow control.
1. |
"Sure Grip" Handwheel — for easy operation.
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Hex Head Packing Nut, made of Forged Brass (ASTM B283) for extra strength, can be easily loosened or tightened providing simple packing replacement.
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Deep stuffing box has "NON-ASBESTOS PACKING". It’s made of Aramid Fiber with PTFE, ideal for leak-free service and reduced operating torque.
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The rising stem design provides visual indication that the valve is open or closed. Stems are made of ASTM B62 bronze. This heavy duty design assures long-life service and protection from dezincification.
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Stem and integral back seat are precision machined for emergency repacking of the valve and keeps the stem thread out of direct contact with the flow media.
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Union Bonnet construction assures leak-tight performance at higher pressures and elevated temperatures. Body and bonnets are made of ASTM B62 bronze. The design, material, and workmanship effectively help to lower maintenance costs and assures long-life service.
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Discs are made of ASTM B62 bronze and are fully guided on precision seating surfaces for accurate alignment and leak-free performance. |
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Watts Cast Iron Valves are manufactured in an integrated valve works exclusively devoted to all valve manufacturing phases such as casting, machining, and assembling, under rigorous quality control. As the performance of iron valves depends greatly on the quality of the castings, we carefully control the quality of molten iron with the most advanced casting facilities and quality control. Watts Cast Iron Valves are widely used in building piping systems, water treatment plants, and industrial facilities.
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“Functionally designed handwheel for
easy gripping and operation.
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Gland bolt made of carbon steel resistant to breaking and bending under high tightening stress.
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Stuffing box of ample depth filled with
non asbestos packing to completely
eliminate leakage around the stem.
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Sturdy bonnet, designed to withstand
high internal pressure.
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Bonnet bolt and nut made of carbon
steel of high tensile strength.
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Stem made of forged brass B124,
C37700
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Body seat rings are cast bronze B62
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Flange dimensions conform to ANSI
B16.1.
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Face-to-face dimensions conform to
ANSI B16.10. |
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For more information please see our
Watts Gate, Globe & Check Valves catalog.
Click here to get the catalog.
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What is dezincification? 
