| CPC B60T 13/686 (2013.01) [B60T 15/36 (2013.01); F16K 11/22 (2013.01)] | 21 Claims |
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1. An unloading valve, comprising:
a housing having a center bore extending longitudinally between a first housing surface and a second housing surface, the housing defining a primary pump inlet, a secondary pump inlet, a collective pump outlet, and a bypass pump outlet, and the housing defining a bypass seat longitudinally between the secondary pump inlet and the bypass pump outlet;
a tappet contained within the center bore and having first and second tappet ends longitudinally spaced by a tappet body, the first tappet end being longitudinally adjacent the first housing surface and the second tappet end being longitudinally adjacent the second housing surface, the tappet being configured for selective longitudinal reciprocal motion within the center bore between first and second tappet positions responsive to fluid pressure at at least one of the primary and secondary pump inlets, the tappet including:
an internal seat defined within a tappet bore longitudinally extending into the tappet body from the first tappet end,
a tappet shoulder located on an external surface of the tappet body for selective sealing engagement with the bypass seat to allow fluid flow in a bypass direction and resist fluid flow in a collection direction longitudinally opposite the bypass direction, and
at least one first tappet cross-aperture extending laterally through at least a portion of the tappet body at a location longitudinally spaced from the first tappet end with the internal seat interposed longitudinally therebetween,
wherein the first tappet cross-aperture is at least partially longitudinally aligned with, and places the tappet bore in fluid communication with, the secondary pump inlet,
wherein the first tappet cross-aperture is in selective fluid communication with the bypass pump outlet, and
wherein at least a portion of the tappet bore is in fluid communication with the primary pump inlet and the collective pump outlet; and
a check ball maintained within the tappet bore in selective sealing engagement with the internal seat, the check ball allowing fluid flow in the collection direction and resisting fluid flow in the bypass direction;
wherein the primary and secondary pump inlets are in fluid communication with the collective pump outlet via the first tappet cross-aperture for flow in the collection direction when the fluid pressure at the primary and secondary pump inlets combined is below a predetermined bypass pressure and the tappet is located in the first tappet position; and wherein
when the fluid pressure at the primary and secondary pump inlets combined is at least one of at and above the predetermined bypass pressure, the check ball engages with the internal seat to resist fluid flow in the bypass direction and the tappet is located in the second tappet position to place the secondary pump inlet into fluid communication with the bypass pump outlet and to maintain fluid communication between the primary pump inlet and the collective pump outlet.
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