A steam trap comprising a housing, a valve seat disposed in said housing and having a first circular orifice therethrough, a valve member having a hemispherical surface, said valve member being movable between a first position in which said hemispherical surface of said valve member sealingly engages said first orifice in said valve seat to block the flow of fluid through said first orifice and a second position in which said valve member is free of contact with said valve seat,WATER POWER CONTROL VALVE said valve seat having a second circular orifice concentric with said first orifice and axially spaced therefrom, and said valve seat including pivot surface means integral with said valve seat and disposed in the diametrical plane of said hemispherical surface of said valve member which plane when said hemispherical surface of said valve member sealingly engages said first orifice passes through said second orifice, float means movable in response to changing condensate level, Butterfly Valvespivotable dual fulcrum lever means connecting said valve member and said float means for providing a relatively high mechanical advantage during initial movement of said valve member away from said valve seat and relatively lower mechanical advantage during subsequent movement of said valve member away from said valve seat,Resilient Seated Gate Valves said dual fulcrum lever means including first fulcrum surface means for contacting said pivot surface of said valve seat during initial movement of said valve member away from said valve seat and second fulcrum surface means for contacting said pivot surface of said valve seat during movement of said valve member away from said valve seat subsequent to said initial movement. The present invention provides a steam trap having a dual fulcrum lever which provides a relatively large initial mechanical advantage in a structure that is both simple to manufacture and long lasting. The high leverage fulcrums of the lever are close to the centerline of the valve orifice to provide a high initial mechanical advantage. The fulcrums pivot on a planar pivot surface which is integral with the valve seat and spaced from the valve orifice and which lies in a plane of the diameter of the valve member when the valve member is seated against the orifice in the valve seat. The planar surface on which the fulcrums pivot is integral with the valve orifice, and as a result the spacing between the valve orifice and the pivot plane can easily be controlled. The pivot surface is relatively broad so that the fulcrums make contact across a relatively large area, reducing wear and extending the operating life of a steam trap constructed in accordance with the present invention. According to the present invention a valve seat has an essentially circular orifice adopted to sealingly receive a hemispherical valve member. The valve seat also has an annular surface surrounding the orifice on which the fulcrum tips of the lever pivot. The pivot surface is coaxial and parallel with the orifice but is axially displaced from the orifice. In effect, the orifice is countersunk from the plane of the pivot surface. The distance between the orifice and the pivot surface is selected so that, when the hemispherical valve member is engaged with the orifice, a diameter of the hemisphere lies in the plane of the pivot surface. This permits the high leverage fulcrum to be moved as close as desired to the centerline of the valve orifice without causing excessive sweep. The pivot surface is an integral part of the valve seat, and consequently it is relatively easy to keep the distance between the orifice and pivot surface within a tight tolerance. The lever and valve member must still be made with a fair degree of accuracy, but this is true of all lever-type steam traps. Elimination of the bracket used in prior art devices means that a steam trap may be made more consistently to an acceptable performance standard at a reduced cost because there is no stackup of tolerances. Moreover, in the present design the fulcrum tips of the lever pivot on the pivot surface of the valve seat which is relatively broad when compared with the surfaces in the prior art bracket. Contact across a broader surface means reduced wear, hence steam traps embodying the present invention have an extended operating life.

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