Directional flow control valve

A valve assembly for directing the flow of a fluid therethrough comprising:

• a body including a generally annular bore extending in an axial direction along a longitudinal axis intermediate a first end and an open second end, the bore having an inner surface which extends in a radial direction about the longitudinal axis, and the body having ports which open radially into the bore including a first port, a second port spaced-apart axially from the first port in the direction of the bore second end and being couplable through the bore in fluid communication with the first port along first fluid flow path, and a third port spaced-apart axially from the second port in the direction of the bore second end and being couplable through the bore in fluid communication with the second port along a second fluid flow path, and the body having valve seats defined about the bore inner surface including a first valve seat disposed axially intermediate the first and the second port, and a second valve seat disposed axially intermediate the second and the third fluid port, the second valve seat having a seating surface and an adjoining lateral wall, the seating surface facing axially in the direction of the bore second end and extending about the bore generally transverse to the bore inner surface, and the lateral wall being disposed generally transverse to and surrounding the seating surface;
• a generally cylindrical stem coaxially received within the bore for reciprocating sliding movement along the longitudinal axis in a first axial direction towards the first end of the bore to a first position opening the first fluid flow path and closing the second fluid flow path, and in a counter second axial direction towards the second end of the bore to a second position closing the first fluid flow path and opening the second fluid flow path, the stem extending along the longitudinal axis from a first end portion received internally within the bore to a second end portion, the stem first end portion having an outer surface;
• a first valve element located on the stem first end portion axially intermediate the bore first end and the first valve seat, the first valve element being axially-spaced apart from the first valve seat in the direction of the bore first end to open the first fluid flow path when the stem is moved to the first position, and contacting the first valve seat in a sealing engagement closing the first fluid flow path when the stem is moved to the second position;
• and
• a second valve element located on the stem first end portion axially intermediate the stem second end portion and the seating surface of the second valve seat, the second valve element contacting the seating surface of the second valve seat substantially along a sealing diameter closing the second fluid flow path when the stem is moved to the first position, and being axially spaced-apart from the second valve seat in the direction of the bore second end to open the second fluid flow path when the stem is moved to the second position,
• the second valve element being formed as a resilient seal ring mounted coaxially on the outer surface of the stem first end portion, the seal ring having radially spaced-apart inner and outer diameter faces and adjoining axially spaced-apart upper and lower end faces, the inner diameter face being supported on the stem first end portion and defining with the outer diameter face a midline diameter of a given radial extent therebetween, the inner diameter face and lower end face adjoining to define a inner lobe portion therebetween disposed radially inwardly of the midline diameter, the inner lobe portion contacting the seating surface of the second valve seat in the first position of the stem and defining the sealing diameter therebetween to be of a radial extent which is smaller than the radial extent of the midline diameter.