Blanking valve having threaded bolt means for increasing sealing pressure

Claim 1

A BLANKING VALVE COMPRISING A PIPE, A HOUSING ON SAID PIPE AND COMMUNICATING WITH THE INTERIOR THEREOF, AN IMPERFORATE PLATE SLIDABLY MOUNTED IN SAID HOUSING, A MANUALLY-OPERABLE STEM SECURED TO SAID PLATE AND SEALED THROUGH THE WALL OF THE HOUSING, THEREBY TO PROVIDE FOR MANUAL ACTUATION OF SAID PLATE TO MOVE THE SAME OUT OF SAID HOUSING INTO SAID PIPE, AT LEAST ONE PAIR OF BOLTS ALIGNED WITH EACH OTHER IN THE DIRECTION OF MOVEMENT OF SAID PLATE, SAID BOLTS BEING THREADED THROUGH THE WALL OF SAID HOUSING AND EXTENDING SUBSTANTIALLY PARALLEL TO THE AXIS OF SAID PIPE; AND A GUIDE MEMBER MOUNTED ON AND SECURED TO SAID BOLTS IN SUCH A MANNER THAT THE BOLTS CAN ROTATE FREELY WITH RESPECT TO SAID MEMBER BUT THE BOLTS CANNOT MOVE LONGITUDINALLY WITH RESPECT TO SAID MEMBER; SAID PLATE HAVING IN ONE FACE THEREOF AN ELONGATED GROOVE EXTENDING IN THE DIRECTION OF MOVEMENT OF SAID PLATE AND RECEIVING THEREIN SAID GUIDE MEMBER, WHEREBY SAID GUIDE MEMBER GUIDES THE MOVEMENT OF SAID PLATE OUT OF SAID HOUSING INTO SAID PIPE AND VICE VERSA; SAID GROOVE HAVING AN OVERHANGING LIP ALONG ITS OUTER EDGE WHICH COMES INTO ENGAGEMENT WITH SAID MEMBER WHEN SAID BOLTS MOVE LONGITUDINALLY PARALLEL TO THE AXIS OF SAID PIPE IN ONE DIRECTION, THEREBY TO CAUSE MOVEMENT OF SAID PLATE IN THIS SAME DIRECTION; AND THE INNER ENDS OF SAID BOLTS COMING INTO ENGAGEMENT WITH SAID PLATE WHEN THE SAME HAS MOVED OUT OF SAID HOUSING AND INTO SAID PIPE AND WHEN SAID BOLTS MOVE LONGITUDINALLY PARALLEL TO THE AXIS OF THE PIPE IN A DIRECTION OPPOSITE TO SAID ONE DIRECTION, THEREBY TO MOVE SUCH PLATE INTO SEALING ENGAGEMENT WITH THE WALL OF SAID PIPE.