Drainable shutoff valve with filter

A shutoff valve comprising:

• a hollow valve body having aligned rear and open front operating bore portions separated at inward ends by a centrally apertured partition;
• said front bore portion having a smooth region from its open outer end inward to a female-threaded region of reduced diameter to receive a moveable closure serving as a valve operator and the back end of the rear bore being closed, thereby defining a valving chamber partitioned at the inner ends of the aligned bore portions;
• said body having an inlet connection and an outlet connection to inlet and outlet passages opening respectively to the valving chamber on opposite sides of the apertured partition affording a flow path valved at the aperture of said partition;
• a valving member guided coaxially of and axially shiftable in the rear bore, between a valve closing location where the valving member seals against said partition to block said aperture, and valve open locations away from the partition;
• a valving-member-operating structure inlcuding a valve operator member comprising a rotatable and axially shiftable plug providing said moveable closure and having
• an inner male-threaded end engaged in the female threaded region of the front bore portion,
• and an unthreaded outer end slidably received in and rotationally and axially slidably sealing with said smooth end;
• and means forming an extension from one of, and engageable endwise with the other of, the respective inner ends of said members, whereby said valving member may be displaced from closed position by an advance of said plug into the front bore by plug rotation in one direction, and said plug may be backed out from said front bore after the valving member reaches the closed position during rotation in the other direction;
• and
• a filter element supported between said plug and aperture.