Automatic switchover valve

Abstract

This invention relates generally to a valve system for the automatic switchover from one source of pressurized fluid to a second, or reserve, source. The switchover valve is actuated automatically in response to the first pressure source failing or reducing to a predetermined value whereupon the valve switches to a second pressure source while sustaining continuous operation. Upon switchover, the valve blocks the inlet of the depleted source such that it can be replaced with a recharged pressure source (gas bottle or liquid tank) without effecting the delivery of working pressure or necessitating additional, costly and complicated valving. Switchover pressure is predetermined by the designed working surface of the axial end of the spool and the force of the opposing biasing spring. Unencumbered movement of the spool during switchover is afforded by the space between the spool end and the opposing spring. Movement through this space prevents false switchovers and exact control over switchover pressure. This invention has the major advantage over the prior art in that this switchover valve affords the economic utilization of a source pressure to it's minimum, but adequate supply pressure prior to switchover. From the above description, those skilled in the art will understand that I have shown only one embodiment of the present invention and that the invention may be embodied, changed or otherwise improved or modified without departing from its spirit and scope. Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.

Dependencies are inferred from the claim text.