60 sit within corresponding grooves 61 in the valve body adjacent to the channel for the valve and the flow passage although the drawings show a manually operated rotatable handle to provide linear movement of the valve paddle such movement could also be achieved by other actuating means such as pneumatic or hydraulic cylinder means digitally controlled linear actuator means and the like such other control techniques would allow remote actuation of the valve other advantageous features of this invention are the fact that the o rings provide a self cleaning function during the course of normal valve operation and usage due to the rubbing or honing of the interior contiguous surfaces of the machined valve slot the fact that two o rings are in place one on each flat surface of the valve stem paddle provides a natural back up seal if one of the two o rings sustains damage through wear or other means the second o ring provides complete sealing capabilities between the upstream and downstream orifices of the process line process line detritus i e fragments or contamination which often collects on the wetted surfaces of the internals of any manifold or valve are naturally wiped off the sealing interior surfaces by motion of the valve stem paddle and o ring arrangement in accordance with the present invention although the valve stem paddle is linearly movable until its o rings are in proper alignment with the flow passageways and the paddle can move no further i e when the paddle has reached the end of its permissible travel its o rings are automatically in proper alignment with the flow passageways.