Abstract: A butterfly valve for controlling the flow of fluid within a bore, including a butterfly and at least one ring extending at least one of substantially and completely around a perimeter of the butterfly and adapted to develop an expansion force in the radial direction when the at least one ring is in a contracted state with respect to the radial direction, wherein the at least one ring is secured to the butterfly in the contracted state and radial expansion due to the developed expansion force of the at least one ring is effectively restrained, wherein the butterfly valve is adapted to operate, when placed in a bore, without friction or substantially without friction between the at least one ring and the bore when the butterfly valve is placed in a closed position within the bore.

Abstract: A butterfly valve for controlling the flow of fluid within a bore, including a butterfly and at least one ring extending at least one of substantially and completely around a perimeter of the butterfly and adapted to develop an expansion force in the radial direction when the at least one ring is in a contracted state with respect to the radial direction, wherein the at least one ring is secured to the butterfly in the contracted state and radial expansion due to the developed expansion force of the at least one ring is effectively restrained, wherein the butterfly valve is adapted to operate, when placed in a bore, without friction or substantially without friction between the at least one ring and the bore when the butterfly valve is placed in a closed position within the bore.

Abstract: A butterfly valve for controlling the flow of fluid within a bore, including a butterfly and at least one ring extending at least one of substantially and completely around a perimeter of the butterfly and adapted to develop an expansion force in the radial direction when the at least one ring is in a contracted state with respect to the radial direction, wherein the at least one ring is secured to the butterfly in the contracted state and radial expansion due to the developed expansion force of the at least one ring is effectively restrained, wherein the butterfly valve is adapted to operate, when placed in a bore, without friction or substantially without friction between the at least one ring and the bore when the butterfly valve is placed in a closed position within the bore.

Abstract: A valve system includes a conduit having a flow of fluid therethrough, and a butterfly valve assembly. The butterfly valve assembly includes a shaft extending obliquely within the conduit, a butterfly disk, and a first bearing assembly positioned on an external surface of the conduit. The butterfly disk includes a passage sized to receive the shaft therethrough, wherein the butterfly disk is operable to restrict the fluid flow through the conduit when the butterfly valve assembly is in the closed position. The first bearing assembly is configured to receive a first end of the shaft therethough, wherein the first bearing assembly includes a plurality of tapered roller bearings circumferentially-spaced within a bearing race and configured to maintain the butterfly disk at a substantially constant axial position when the butterfly valve assembly is in the closed position.

Abstract: A vacuum toilet system comprises a tank having a sewage inlet connection for entry of sewage into the tank, a level detector establishing a maximum filling level for the tank, and a spray nozzle assembly for distributing cleaning liquid inside the tank. The spray nozzle assembly comprises an axle member having a first end portion provided with a mechanism attaching the axle member to the tank and a second end portion defining a vertical axis of rotation. The axle member is hollow and defines a passage that extends from the first end portion of the axle member and debouches at an outlet at the second end portion thereof. The spray nozzle assembly comprises a spray head mounted on the second end portion of the axle member for rotation about the vertical axis of rotation.