| 摘要 |
An electrical pressure switch that can be readily adapted for either normally open or normally closed operation and that has opposed annular seats, a movable contact and ball valve movable between and individually engageable with the seats, and an O-ring uniquely associated with the ball valve and a related sealing surface in seated, unseated and all intermediate positions of the valve to maintain an effective seal at all times against fluid pressure to which the switch is connected. |
