Centralized greasing device with multiple operational checks

Claim 1

In a stage for a centralized greasing installation which has a certain number of such stages assembled in blocks; said stage having a lubrication air chamber, a resetting air chamber, and a metering piston located between said chambers; said air chambers each being provided with an adjusting stopper which has a bore connected to atmosphere, said piston having rods with ends which close said bores at opposite ends of piston travel; supply means for supplying lubricant to said piston, said supply means including a primary duct means, a branched connection, and a double acting valve for supplying intermittently pressurized lubricant to said piston; means for connecting said lubrication air chamber to lubrication air chambers of other such stages and to a common air source having a limited flow rate and to a common pressure switch; means for connecting said resetting chamber to resetting air chambers of other such stages and to another common air source having a limited flow rate and to another common pressure switch, whereby air pressure measurements permit verification that all of the metering pistons of said installation have completed their travel; the improvement wherein said stage is provided with a secondary duct for conveying lubricant expelled by the metering piston to a point to be greased, said secondary duct including an encasing conduit with a smaller diameter tube therein to define a space, a leakage control air chamber in communication with said space, and means for connecting the leakage control air chamber to leakage control air chambers of other stages in order to check overall the absence of leakage in all secondary ducts of the installation.