Butterfly valve

Claim 2

A readily removable and replaceable butterfly valve and seat assembly, comprising: a valve body having a pair of spaced apart parallel side walls defining a valve seat cavity therebetween and having an access opening to the cavity; a substantially ring shaped resilient seat having substantially parallel opposite end surfaces; annular, rigid ring means imbedded in the resilient seat substantially concentric therewith; a butterfly valve pivotally mounted within the seat and cooperable therewith between open and closed positions; and means externally of the seat and engageable therewith to expand the seat in an axial direction into sealing engagement with the valve body side walls.

Claim 3

A butterfly valve and seat assembly as in claim 1, wherein the means engageable with the seat to expand it in an axial direction comprises an annular clamp ring disposed about the seat substantially concentric with the rigid ring means and tightenable about the seat to cause said axial expansion of the seat.

Claim 4

A butterfly valve and seat assembly as in claim 2, wherein the rigid ring means comprises metal and a pair of rings are embedded within the seat on opposite sides of the butterfly valve adjacent the respective opposite parallel end surfaces of the seat, and a clamp ring is disposed around the seat radially oUtwardly of each of said rigid metal rings.

Claim 5

A butterfly valve and seat assembly as in claim 1, wherein the means engageable with the seat to expand it in an axial direction comprises a plurality of means extended through a portion of the valve body and through the parallel side walls of the valve body into the rigid ring means embedded within the seat, said plurality of means cooperatively engaged with the valve body to draw the rigid ring means toward the parallel side walls of the valve body and thus to expand the seat in an axial direction into sealing engagement with the valve body side walls.

Claim 6

A butterfly valve and seat assembly as in claim 4, wherein said rigid ring means comprises metal and said plurality of means comprises a plurality of threaded cap screws extended from outside the valve body through the parallel side walls of the valve body and into threaded engagement with the rigid metal ring means, so that threaded adjustment of the cap screws in a first direction pulls the rigid ring means toward the side walls of the valve body to urge the seat into tight sealing engagement therewith, and threaded adjustment of the cap screws in a second direction releases the rigid ring means to enable the seat to move out of tight sealing engagement with the valve body side walls whereby the seat may be removed from the valve body.

Claim 7

A butterfly valve and seat assembly as in claim 5, wherein said rigid ring means includes a pair of rings embedded in the seat on opposite sides of the butterfly valve adjacent the opposite end surfaces of the seat, and a plurality of cap screws are threadably engaged with each of said rings in circumferentially spaced relationship around the rings.