Valve actuator

Abstract

The present invention relates to a valve actuator comprising a support member for supporting a rotatable positioning element operatively connected to a valve rod. The valve actuator further comprises a track follower adapted to follow at least part of a track provided in the positioning element. The track follower is biased against at least part of the track by a resilient member. The rotatable positioning element comprises a curved outer portion arranged in an associated bearing formed in the support member.

1 . A valve actuator comprising:
 a support member comprising a bearing for supporting a rotatable positioning element on the bearing, and   a track follower being operatively connected to a valve rod, the track follower being adapted to follow at least part of a track provided along an interior surface of the positioning element upon rotation thereof, the track follower being biased against at least part of the track provided by the interior surface of the positioning element,   wherein the track follower comprises a set of ball bearings or wheels rotatably mounted in relation to the valve rod, each ball bearing or wheel being biased against at least part of the track provided by the interior surface of the positioning element and arranged to follow said track upon rotation of the positioning element.   
     
     
         2 . The valve actuator according to  claim 1 , wherein the rotatable positioning element comprises a curved outer portion arranged in the bearing of the support member, and wherein the bearing of the support member comprises a curved inner portion corresponding in shape with the curved outer portion of the rotatable positioning element. 
     
     
         3 . The valve actuator according to  claim 1 , wherein the positioning element comprises a curved outer portion that is shaped as an arc of a circle. 
     
     
         4 . The valve actuator according to  claim 1 , wherein the bearing of the support member is shaped as an arc of a circle. 
     
     
         5 . The valve actuator according to  claim 1 , wherein the positioning element comprises a substantially circular disc, the circular disc having a solid part and a non-solid part. 
     
     
         6 . The valve actuator according to  claim 5 , further comprising a hand grip rigidly connected to the solid part of the positioning element. 
     
     
         7 . The valve actuator according to  claim 1 , wherein the support member comprises a guiding arrangement for the track follower. 
     
     
         8 . The valve actuator according to  claim 1 , further comprising a resilient member for biasing the track follower against at least part of the track provided by the positioning element, the resilient member comprising a helical spring arranged coaxially around the valve rod. 
     
     
         9 . A valve comprising a valve actuator according to  claim 1 , the valve actuator controlling the position of a closing arrangement relative to a valve seating of the valve.