Butterfly Valves And Construction Thereof

A butterfly type valve comprising:

• a valve body defining a flow passage therein;
• a closure disc disposed in the flow passage, the closure disc having an axis of rotation about which the closure disc rotates between open and closed positions with respect to the flow passage;
• a resilient cylindrical body liner disposed within the valve body, the resilient cylindrical body liner having a circumferential sealing surface that is engaged by the periphery of the closure disc to establish a seal when the closure disc is rotated to a closed position;
• at least one resilient band being at least partially interposed between the valve body and the resilient cylindrical body liner, wherein at least a portion of the resilient band distant from the axis of rotation is tapered to a reduced thickness, such that the reduced thickness reduces the forces associated with the engagement by the closure disc, to thereby reduce the unseating torque required to overcome the engagement with the liner's circumferential sealing surface.

A butterfly type valve comprising:

• a valve body defining a flow passage therein, the valve body having at least one bore therein transverse to the flow passage;
• a closure disc disposed in the flow passage, the closure disc having at least one stem depending therefrom that is received in the at least one transverse bore and defines an axis of rotation about which the closure disc rotates between open and closed positions with respect to the flow passage;
• a resilient cylindrical body liner disposed within the valve body, having a circumferential sealing surface that is engaged by the periphery of the closure disc when the closure disc is rotated to a closed position, which engagement establishes a seal between the circumferential sealing surface and the periphery of the closure disc;
• at least one partially circumferential resilient band being at least partially interposed between the valve body and the resilient cylindrical body liner, wherein a least a portion of the resilient band that is distant from the axis of rotation has a reduced thickness, such that the reduced thickness reduces the forces associated with the deflection of the resilient cylindrical body liner, to thereby reduce the unseating torque required to overcome the resistance to movement of the closure disc caused by the engagement with the circumferential sealing surface.

A butterfly type valve comprising:

• a valve body defining a flow passage therein;
• a closure disc disposed in the flow passage, the closure disc having at least one stem depending therefrom, about which the closure disc rotates between open and closed positions with respect to the flow passage;
• a resilient cylindrical body liner disposed within the valve body, the resilient cylindrical body liner including at least one opening therein for receiving the at least one stem, and including a circumferential sealing surface that is engaged by the periphery of the closure disc to establish a seal between the circumferential sealing surface and the periphery of the closure disc when the closure disc is rotated to a closed position;
• at least one resilient band being at least partially interposed between the valve body and the resilient cylindrical body liner, wherein the at least one resilient band includes a first portion having an opening therein for receiving the at least one stem, and at least a portion of the band depending from the first portion is tapered to a reduced thickness effective for reducing the unseating torque required to overcome the resistance to rotation of the closure disc caused by the engagement between the periphery of the closure disc and the liner's circumferential sealing surface.