Abstract: An impedance seat (10) having an impedance element (19) that can be mounted in conjunction with a seat in a ball valve (52). The impedance seat has a concave surface (16) matching the curvature of the ball (76) and a plurality of flow paths (18) formed through it. An impedance assembly can have a plurality of stacked plates (34) that define the flow paths. The impedance seat can have a full flow window (104) having a radius that matches the profile of a flow bore (86) of the ball valve in an intermediate position. The impedance seat can be easily fabricated to provide improved impedance characteristics, and can be used in an original ball valve, or in a retrofit for an existing valve.

Abstract: A method of forming a ball valve element for a rotary ball valve assembly, the method comprising the steps of: (a) inserting an impedance element through an insertion opening of a ball valve element into a bore; (b) forming a fluid opening in the ball valve element which is non-rectilinearly aligned with the insertion opening and which communicates with the bore; and (c) sealing the insertion opening. A ball valve element for a rotary ball valve assembly formed using such a method; and a rotary ball valve assembly comprising a ball valve element formed using such a method are also provided.

Abstract: A method of forming a ball valve element for a rotary ball valve assembly, the method comprising the steps of: (a) inserting an impedance element through an insertion opening of a ball valve element into a bore; (b) forming a fluid opening in the ball valve element which is non-rectilinearly aligned with the insertion opening and which communicates with the bore; and (c) sealing the insertion opening.

Abstract: A method of forming a ball valve element for a rotary ball valve assembly, the method comprising the steps of: (a) inserting an impedance element through an insertion opening of a ball valve element into a bore; (b) forming a fluid opening in the ball valve element which is non-rectilinearly aligned with the insertion opening and which communicates with the bore; and (c) sealing the insertion opening. A ball valve element for a rotary ball valve assembly formed using such a method; and a rotary ball valve assembly comprising a ball valve element formed using such a method are also provided.

Abstract: A method of forming a ball valve element for a rotary ball valve assembly, the method comprising the steps of: (a) inserting an impedance element through an insertion opening of a ball valve element into a bore; (b) forming a fluid opening in the ball valve element which is non-rectilinearly aligned with the insertion opening and which communicates with the bore; and (c) sealing the insertion opening.

Abstract: A rotary ball valve assembly for a rotary ball valve comprises a rotary closure element and an impedance assembly. The closure element is rotatable about a rotational axis, and has a through-bore defining a flow inlet and a flow outlet. The impedance assembly is positioned, at least in part, within the bore of the closure element. The impedance assembly includes a plurality of flow passages therethrough. An inlet and/or outlet of two or more of the flow passages is elongate and arcuate so that, in use, as the closure element rotates, the arcuate elongate inlet and/or outlet of each flow passage which is exposed is fully or substantially fully opened.

Abstract: A rotary ball valve assembly for a rotary ball valve comprises a rotary closure element and an impedance assembly. The closure element is rotatable about a rotational axis, and has a through-bore defining a flow inlet and a flow outlet. The impedance assembly is positioned, at least in part, within the bore of the closure element. The impedance assembly includes a plurality of flow passages therethrough. An inlet and/or outlet of two or more of the flow passages is elongate and arcuate so that, in use, as the closure element rotates, the arcuate elongate inlet and/or outlet of each flow passage which is exposed is fully or substantially fully opened.