Abstract: The present invention is directed for use in a valve assembly including a housing having an axis and defining an interior, with fluid provided in the housing and substantially filling the housing interior, a valve stem disposed in the housing interior and a piston attached to the valve stem, wherein the piston and valve stem are moveable along the housing axis within the housing interior between first and second positions. The present invention includes a valve actuation control device disposed in the housing interior, the valve actuation control device allowing the fluid to freely flow from one side of the piston to the other side during at least a portion of the piston's movement between the first and second positions.

Abstract: The present invention is directed for use in a valve assembly including a housing having an axis and defining an interior, with fluid provided in the housing and substantially filling the housing interior, a valve stem disposed in the housing interior and a piston attached to the valve stem, wherein the piston and valve stem are moveable along the housing axis within the housing interior between first and second positions. The present invention includes a valve actuation control device disposed in the housing interior, the valve actuation control device allowing the fluid to freely flow from one side of the piston to the other side during at least a portion of the piston's movement between the first and second positions.

Abstract: For use in a valve assembly including a housing having an axis and defining an interior, with fluid provided in the housing and substantially filling the housing interior, a valve stem disposed in the housing interior and a piston attached to the valve stem, wherein the piston and valve stem are moveable along the housing axis within the housing interior between first and second positions, a valve actuation control device is provided which is disposed in the housing interior, the valve actuation control device allowing the fluid to freely flow from one side of the piston to the other side during only a first portion of the piston's movement between the first and second positions.

Abstract: The present invention is directed for use in a valve assembly including a housing having an axis and defining an interior, with fluid provided in the housing and substantially filling the housing interior, a valve stem disposed in the housing interior and a piston attached to the valve stem, wherein the piston and valve stem are moveable along the housing axis within the housing interior between first and second positions. The present invention includes a valve actuation control device disposed in the housing interior, the valve actuation control device allowing the fluid to freely flow from one side of the piston to the other side during at least a portion of the piston's movement between the first and second positions.

Abstract: A valve stem actuator for a slurry valve or the like includes a support frame extending from the valve body to a linear operator having a cylinder and piston. Means are provided for connecting the piston rod to the valve stem and means reciprocally mounted on the support frame rotate the valve stem with respect to the valve body independently of the linear movement of the valve stem to dislodge accumulated crust to permit the valve disc to properly seat to prevent fluid flow through the valve. The linear operator is preferably pneumatically or hydraulically actuated and the rotary actuator preferably comprises an air or hydraulically actuated rack engageable with the valve stem. The valve stem actuator is useful for new valves or for retrofit of present slurry valves or the like.