Abstract: A hydropneumatic monitoring device in which a hydraulic fluid passageway is controlled by a piston and plunger spring biased in one direction and shiftable by air pressure in opposition to the bias for aligning a passageway-connecting bypass in the plunger with the passageway which is intersected by the plunger. Air pressure metered through the piston passes to an air passage. Air pressure failure or blockage in the air passage cause deviation of the piston and plunger from a state of open passageway equilibrium, for blocking the passageway.

Abstract: A cyclical lubricant feeder utilizing series spool valves to dispense measured quantities of lubricant to dispensing outlets from a common feed source with a plurality of the spool valves arranged in series in valve block assemblies which in turn are in series with one another whereby dispensing through the outlet for each spool valve in a block assembly is in progression with the other outlets from the spool valves in the valve block assembly is provided with a control valve controlling inlet and outlet flow to the valve block assembly bypassing flow from the inlet to the outlet when all of the valves in the block have been shifted to one side and bypassing flow from the outlet to the inlet upon reverse lubricant flow to the block only when all of the valves in the block have been shifted to the other side.

Abstract: A lubricant applying system which may have a plurality of lubricant injectors along a lubricant supply/return passage which receives lubricant under predetermined pressure through one end from a source for discharging and sequentially recharging the injector in one phase and in a second phase after the recharging permitting return of surplus lubricant from the injector through the passage to the lubricant source. A pressure sensor connected to the opposite end of the passage monitors pressure conditions in the passage. The lubricant injector has a displacement plunger and a cooperatively related metering plunger. The displacement plunger is responsive to lubricant passage line pressure which drives the displacement plunger in a displacement stroke, during which a passageway is connected by the displacement plunger with a metering chamber from which the metering plunger is driven by the pressure and the metering chamber charged while the metering plunger closes the lubricant passage.