Abstract:
A butterfly valve (30) is described in which the plate member (32) is in facing relationship with a hollow shaft (34) and is moved by pistons (50, 52) disposed in the shaft. The pistons (50, 52) are mechanically coupled to the plate member (32) by cam followers (58, 60) which ride along cams (40, 42, 46, 48) formed in the shaft (34) and plate member. The plate member (32) is capable of both revolutionary and translational movement relative to the longitudinal axis of the shaft (34) toward the end of minimizing the externally supplied energy required to operate the valve (30). The pistons (50, 52) collectively have a center of mass that coincides with the center of the duct (68) toward the end of minimizing vibrational effects.
Abstract:
A butterfly valve (10) includes a duct (12) defining a fluid flow path (16) and a plate-like valve member (22) pivotal in the duct to in one position span and close the latter. The valve member (22) is pivotal to a second position spanning the duct and extending parallel to the flow path to allow fluid flow therein. Means (30, 32, 34, 64, 66, 68) are provided for altering the effective area distribution of the valve member (22) about its pivot axis (20) to decrease the operating torque required by the inventive valve in comparison with conventional butterfly valves.
Abstract:
A butterfly valve (10) includes a duct (12) defining a fluid flow path (16) and a plate-like valve member (20) pivotal in the duct to in one position close the latter. The valve member (20) is pivotal to a second position spanning the duct (12) and extending parallel to the flow path to allow fluid flow therein. Means (28, 34, 60) are provided for altering the effective area distribution of the valve member (20) about its pivot axis (22) to effect opening and closing of the inventive valve in response to fluid pressure forces acting thereon.
Abstract:
A flow modulator (48) for a butterfly valve (40) incorporates a first protrusion (64) on the high-pressure side (52) of the modulator and a second protrusion (66) on the low-pressure side (54). The second protrusion (66) is spaced from the leading edge (60) to define a surface portion (88) of the low-pressure side (54). In operation, the second protrusion (66) functions as a flow restrictor that increases pressure in a region (86) of the flow path (44) bordered in part by the second protrusion and the surface portion (88). This increase in pressure serves to minimize the net aerodynamically-induced closing torque exerted on the modulator (46). The height of the second protrusion and its distance from the leading edge are shown to be important design parameters. In addition, the user of a third protrusion (114) for reducing torque drop-off at high rotational angles is disclosed.
Abstract:
A butterfly-type check valve (30) employs a secondary check valve (38) that is carried on the valve plate (36). The valve plate (36) is revolvable and translatable relative to the pivot shaft (34). In operation, the check valve (30) opens in response to a change in aerodynamic forces which act on the valve plate (36), the change being effected as a response to the opening of the secondary check valve (38). As the valve plate (36) rotates to an open position, its revolutionary movement relative to the shaft (34) changes the location of pivot points (40) relative to the surface (62) of the plate. This changes the areas (42, 44) of the surface (62) on both sides of the pivot points (40) so that the aerodynamic forces cause the valve (30) to open still further.
Abstract:
A method for facilitating control of a butterfly valve, butterfly valves (40, 180) adapted for use with the method, and a fluid system (242) incorporating such valves are disclosed. All three use or incorporate butterfly valve structure that provides for relative translational movement (246) between the valve plate (42, 182, 248) and a pivot axis (232) in order to alter fluid dynamic torque exerted on the valve plate.
Abstract:
A butterfly valve method and apparatus (10) employing a variably positionable pivot shaft (30). The apparatus (10) comprises a duct (16), a valve plate (12), and a pivot shaft (30). Near closed rotational positions of the valve plate (12), the plate is pivotally supported by a support shaft (18) which is movably secured to the duct (16). Over a substantial range of open rotational positions, the valve plate (12) is pivotally supported by the pivot shaft (30), which is translationally movable relative to the valve plate (12) so that fluid-dynamic torque exerted on the plate can be altered. The method comprises the steps of rotationally moving the valve plate (12) away from the closed position whereby fluid-dynamic torque is increased, and translationally moving the pivot shaft (30) relative to the valve plate whereby the torque is then decreased.
Abstract:
A method for opening a sealingly closed, balanced-torque butterfly valve, and apparatus adapted for use with the method. The butterfly valve (40) comprises a valve plate (42) having a peripherally disposed seal (162) seated in an annular recess (160). A flow passage (164, 166) is formed in the valve plate (42) and fluidically connects the recess (160) to the downstream-facing surface of the valve plate. A check valve (168) is disposed in the flow passage (164, 166) to alternately block or permit flow therethrough. Outwardly directed pressure exerted by high-pressure fluid on the seal (162) is relieved by opening the check valve (168) in response to a slight translational movement of the valve plate (42) relative to a rotatable shaft (72) which pivotally connects the valve plate to the duct (146).
Abstract:
A balanced-torque butterfly valve (40) incorporates a pivot mechanism (52) designed to provide for bimodal movement of the valve plate (42). The valve plate (42) has a cavity (54) formed therein to receive the pivot mechanism (52) and to accommodate translational movement of the valve plate relative to the mechanism. This eliminates fluid dynamic effects that would be produced if the mechanism were positioned in the flow path (44) and external to the valve plate (42). The pivot mechanism (52) comprises a center shaft (70) rotatable relative to the valve plate (42), and a carrier shaft (72) which is in fixed rotational relation to the valve plate (42) and extends through the mounting body (46). This permits both translational movement of the valve plate (42), and detection of its rotational position from a vantage point outside of the flow path (44). In addition, the carrier shaft (72) cooperates with bearings (104) to minimize load-bearing requirements of rack and pinion gears (64, 66, 116, 118) which are used to convert rotational movement of the center shaft (70) to translational movement of the valve plate (42).
Abstract:
This invention relates to butterfly valve methods and apparatus which employ or incorporate structure that permits translational movement of the valve plate (20) relative to the pivot mechanism (52). The method having a valve plate that is moved from a first rotational position toward a second rotational position while being subjected to the net torque exerted thereon by fluid conveyed along the flow path. The net torque resists the forementioned movement and tends to rotate the valve plate (20) back toward the first rotational position. The movement of the valve plate is characterized by a succession of rotational and translational movements, the translational movements serving to facilitate the rotational movements by decreasing the net torque. In the apparatus both rotational and translational movement is provided for by a butterfly valve which comprises in combination: a mounting body (41) defining a portion of a flow path for a fluid to be conveyed therethrough; a valve plate (20) supported within and transecting the flow path; pivot means journalled in the mounting body for supporting the valve plate; a differential gear operably connected to the pivot means (52) to transmit torque thereto; and an input shaft (48) operably connected to the differential gear (50) to apply input torque to the latter. The differential gear functions as a mechanical resolver through which either rotational or translational movement of the valve plate (20) is produced in response to rotation of the input shaft (48).