Patent GB-938034-A (GB)
Title: A centralized lubrication system
IPC: F16N25/02
Filed: 1961-09-15
Abstract: 938,034. Lubricators &c. EATON MANUFACTURING CO. Sept. 15, 1961 [Nov. 16, 1960], No. 33244/61. Class 12 (3). A centralized lubrication system which incorporates a warning means in event of failure in any part of the system comprises a lubricant supply line 1 which conveys lubricant under pressure to lubricator valves in manifolds 5, 7 and 8, the supply line 1 being provided with a shut-off valve 4. The operation of the lubricator valves is effected by hydraulic fluid under pressure which is supplied from a reservoir 15, by a pump 16, through a supply line 17 to manifolds 5, 7 and 8. Ahead of the first manifold 5 an accumulator 20 with free piston 21 is located and which permits pressure interconnection between the lubricant and fluid supply lines 1 and 17, respectively. The system is operated by suitable programming means which may be in the form of a time clock 30 energized electrically with control centre 31. When this occurs the lubricant shut-off valve 4 is opened and the hydraulic fluid pump motor 16 is started. The accumulator 20 receives lubricant from the inflow via valve 4 and the fluid pump 16 supplies fluid to the accumulator at the other side of the piston, which, building up to a higher pressure than the lubricant forces said lubricant back into the supply line 1 until the accumulator piston 21 can move no farther. The fluid pressure continues to rise further until it reaches a predetermined value at the valve manifolds when pressure switch 32 in the fluid outlet from manifold 8 energizes a reset relay 33 and completes the lubricating cycle by causing valve 4 to close, fluid pump 16 to stop and relief valve 24 to open. At this point the pressure differential between the fluid supply line 17 and lubricant supply line 1 operates the lubricating valves in the manifolds 5, 7 and 8 in one direction and thus meters lubricant to half of the points served by the system. With the cycle stopped the fluid pressure will reduce, by permitting the return of fluid via pipe 23, which permits the return of the lubricators to their normal positions in the manifolds and subsequent displacement of lubricant to the other half of the points in the system. When the fluid pressure in line 17 falls to a predetermined level the pressure switch 32 makes a low-pressure contact to initiate a further cycle of operation. A highlow pressure switch 35 located in the fluid supply line 17 ahead of the first manifold 5 is preset to operate when a predetermined high-pressure is exceeded so that if a particular lubricant feed line from one of said manifolds is blocked or broken, or a lubricator valve malfunctions and causes high pressure by-pass valves to operate, said switch will energize an alarm signal which may be in the form of a signal light 36 in a bank of such lights 37. Similar switches 38, 39 for energizing lamps 40, 41 may be provided in the line 17 for manifolds 7 and 8. Other switching means may also be employed in the form indicated above to provide warning means at other points in the system. The lubricating valves for pumping the predetermined quantities of lubricant to given parts in the system are of the multi-land reciprocating piston type and comprise a pilot piston 93 and a main piston 97 and are slidably movable in respective bores 99 and 100. Lubricant enters the valve member through-bore 105 and via passage 106 to bore 99 of the pilot piston 93. At the same time fluid enters the bore 99 and acts on the other (right-hand) end 108 of the pilot piston to force said piston to the left. Lubricant at the left-hand end is therefore forced back into bore 105 until relief portion 109 connects via passage 110 in the pilot piston and uncovers passage 111 leading to the left-hand end of the main piston 97. Annular relief portion 112 of the pilot piston will then be in position to connect passage 113 leading to the righthand end of piston 97 which may then discharge lubricant to bearing B by the movement of main piston to the right. The pressure changes between the lubricant and fluid within the valve similarly provide movement of the pistons to discharge lubricant to bearing A. A centralized lubrication system of this type may handle either grease or oil and function in such a way as to indicate line leakage or stoppage without interrupting the operation of the unaffected valves and give visual indication of the point of operational failure.