Differential pressure shuttle valve

Abstract

The differential pressure shuttle valve (10) comprises a stepped bore (14) having enlarged (16) and reduced (18) diameter sections. The reduced diameter section (18) communicates with first (20), second (22), and third (24) openings, and the enlarged diameter section (16) is divided into two chambers (50, 60) by an enlarged end (42) of a valve member (40, 140, 240). The valve member (40, 140, 240) includes a central through passage (48, 148, 248) which communicates with the first chamber (50) between the enlarged end (42) of the valve member (40) and the enlarged diameter section (16) of the stepped bore (14). The second chamber (60) is defined between the enlarged end (42) of the valve member (40) and a shoulder (17) disposed between the enlarged (16) and reduced (18) diameter sections of the bore (14). The second chamber (60) communicates with a fourth opening ( 70) and includes therein a resilient member (80) which biases the valve member (40, 140, 240) away from the first opening (20). A pressure differential across the valve member (40, 140, 240) causes the valve member (40, 140, 240) to shuttle and compress the resilient member (80) so that a reduced end (44, 144, 244) of the valve member (40, 140, 240) engages an end of the bore (14) or insert (28, 90, 228) such that the first opening (20) is isolated from the second (22) and third (24) openings.