Patent ID: 8474480

Claim:
A valve comprising: a housing having interior side walls defining a bore, the bore comprising: a first chamber having no externally communicating fluid port formed in the side walls thereof; and one or more additional chambers axially offset from the first chamber; a plurality of fluid ports formed in the side walls of the said one or more additional chambers of the bore, each fluid port communicating with the housing exterior, the plurality of fluid ports including a first fluid port; and a spool disposed in slidable engagement with the housing within the bore and reciprocably movable therethrough, the spool comprising: axially spaced adjacent first and second lands closely received within the bore outside the first chamber thereof; and a third land closely received within the first chamber of the bore in axially offset relationship to the first and second lands, the third land having cross-sectional dimensions greater than the corresponding dimensions of the first and second lands; in which the one or more lower chambers comprise: a second chamber within which the first fluid port is formed; and a first passageway linking the first and second chambers; and in which the valve further comprises: a first valve seat surrounding the first passageway and sized to closely receive the second land of the spool.