Dual pressure shuttle valve

A shuttle valve comprising:

• a first adapter having a first valve seat with a first diameter;
• a second adapter having a second valve seat with a second diameter, wherein the first diameter is larger than the second diameter;
• a body operationally attached to the first adapter and second adapter, the body including an outlet port and a shuttle, the shuttle including:
• a first portion for engagement with the first adapter, the first portion having first apertures;
• a second portion for engagement with the second adapter, the second portion having second apertures, wherein the first apertures are smaller than the second apertures.

A shuttle valve adapted for use with pressurized fluid sources of varying pressures, the valve comprising:

• a body having a pair of opposing coaxial adapter ports, a transverse function port, and a passageway allowing fluid communication between all of the ports, each adapter port in fluid communication with one of the fluid sources and the function port in fluid communication with the downstream apparatus;
• an adapter functionally attached to a first of the adapter port, the adapter having a first valve seat at one end and a inlet port at an opposing end, with a bore therebetween to permit fluid flow from the inlet port past the first valve seat;
• a shuttle valve assembly including;
• i. an elongate tubular adapter engaging the other adapter port, the elongate tubular adapter having a second valve seat at one end and an inlet port at another end, with a central bore in between to permit fluid flow from the inlet port past the second valve seat;
• ii. a shuttle coaxial with the first valve seat and the second valve seat, the shuttle slideably moving from alternative sealing engagement with the first valve seat to sealing engagement with the second valve seat, the shuttle having an elongate portion and an opposing stub portion;
• iii. a guide functionally attached to an elongate end of the shuttle, the guide sized and arranged to slide in the elongate tubular adapter;
• iv. a spring positioned in the elongate tubular adapter and surrounding the elongate portion of the shuttle, the spring captured between the guide and a shoulder in the central bore of the elongate tubular adapter, the spring urging the shuttle into sealing engagement with the second valve seat;
• and
• v. the short portion of the shuttle having a hollow center, an open end and at least one aperture, to generate substantial flow friction such that the force of the spring is substantially exceeded when the second valve seat is engaged, as fluid from the inlet port on the short adapter occurs across the hollow center in the short adapter past the first valve seat as compared with fluid flow through the second inlet port and past the second valve seat.
• vi. the elongate portion of the shuttle having a hollow center, an open end and at least one aperture proximate the spring, all to allow a substantial flow of fluid from the inlet port on the elongate tubular adapter through the hollow center in the elongate tubular adapter past the second valve seat.
• vii. a circumferential collar portion of the shuttle having an outer diameter that produces a pressure controlled area on the elongated portion of the shuttle between the starting position of the shuttle, with low pressure fluid flowing, and the mid position of the shuttle, with low pressure fluid flow diminished.