Patent Publication Number: US-5289899-A

Title: Apparatus and method for lubricating conveyors

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a new and improved lubricant applicator for conveyor systems, especially in large facilities used in food processing, packaging plants, and the like. Typically, conveyors contemplated by this invention are used in food canning and soft drink manufacturing facilities, breweries, packaging facilities, dairies, etc. Moreover, this invention can be employed in industrial operations in general. 
     Conveyors employed in some of the large facilities noted 
     above are generally very long, and some can extend for as much as several hundred feet; the conveyor components themselves are also very heavy. If they are not lubricated, the conveyors will become excessively worn and ultimately break. If this occurs, and because conveyors can operate with heavy loading and under high tension, chain breakage is extremely dangerous. As a result, the industry practice is to over-lubricate these conveyors, which is not only expensive, but in addition, excessive lubricant causes a slippery condition that is dangerous to personnel. 
     It would be preferable to eliminate the need to lubricate a conveyor when a particular section of a conveyor system is shut down, either temporarily during a run, or for periods of time, say during a shift change, or for repairs, and during routine maintenance, etc. This would result in lubricant savings and also reduce sewage charges due to excessive use. 
     In Applicant&#39;s U.S. Pat. No. 5,129,481 issued Jul. 14, 1992, there is described a conveyor driven system which connects through a bladder accumulator which feeds lubricant through nozzle applicators and onto the conveyor, the application times being controlled by the conveyor movement. 
     The patented system is adapted t replace conventional electrical actuated devices which are expensive, and subject to electrical breakdowns due to moisture accumulation which causes maintenance problems and slows down plant operations. 
     One problem arising with bladder accumulators is that the response time of the accumulator is not sufficiently rapid to feed the lubricant in a pulsating manner to a very rapidly moving conveyor system. Instead, the bladder accumulator applies lubricant continuously to the rapidly moving conveyor rather than on an intermittent or pulsating basis, and this type of operation precludes an effective control of lubricant application. 
     In addition, each station where lubricant is applied requires a bladder accumulator and associated equipment. However, it would be preferred to use a single lubricant applicator system to service, say, multiple lubrication stations instead of only a single station. 
     Also, it would be preferred to control the application of lubricant, not only to a rapidly moving conveyor, and to control multiple lubrication stations, but also to avoid the use of an electrically controlled applicator system. 
     THE INVENTION 
     According to the invention, there is provided a lubricating system including an air-driven, delay valve or relay which is driven from the conveyor system to be lubricated, and which connects to a counter which controls a valve that passes lubricant in a pulsating or intermittent fashion from a lubricant feed supply to the conveyor. 
     When the conveyor is not moving, the feed supply will be turned off, and when the conveyor is in motion, the amount of lubricant supplied to the conveyor will depend on the conveyor speed. Since the response times of the system are very rapid, say about 10 milliseconds, it is easily accommodated by the lubricating system of this invention and produce pulses which will suitably lubricate a conveyor moving at speeds of up to about 1,000 ft./min. 
     Moreover, the system can be used to control a number of conveyors from a single station, and this will of course reduce overall costs of a lubricating system for a plant. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a flow diagram showing the lubrication system of this invention; and, 
     FIG. 2 is a flow diagram showing the connections between major components of the system. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A system flow diagram 10 of this invention and the connections between specific components are shown in FIGS. 1 and 2, and the component catalogue listings shown in FIG. 1 are supplied by Clayton Controls. The system flow diagram comprises a conveyor 11 which is lubricated from one or more nozzles 12, 13; suitable nozzles are described in Applicant&#39;s U.S. Pat. Nos. 5,033,676 and 5,115,978. 
     A cam follower 14 is driven by the conveyor 11 such as a belt or a conveyor shaft drive, and the cam follower is air connected to an actuator sequencer 15 which sends an air, actuating signal to a normally closed, three-way valve actuator 16. The signal from the sequencer 15 will open valve 16 which then sends an actuating air signal to a delay or pilot valve 17 that corresponds to each revolution of the cam follower. 
     A counter 18 is pre-set to determine the number of revolutions the cam follower 14 undergoes before lubricant is fed to the conveyor, and each revolution of the cam follower will cause the counter to decrement to zero from its initial pre-set number. When the counter reaches zero, a counter zero signal is sent to the delay valve 17 and an `on` signal will then be sent from the delay valve to a normally closed, on-off fluid valve 19; also, a counter reset signal is sent from the delay valve to the counter. 
     As shown in FIG. 2, an air actuated auxiliary valve 21 may be employed to ensure that an air pulse of sufficient force is applied from delay valve 17 to either reset the counter and/or turn on the fluid valve 19. 
     The fluid valve 19 is actuated by a valve actuator 20 which is set to open when a pre-set minimum pressure is applied from the delay valve. Pulse signals from the counter and on-times of the delay valve are preset to accommodate for lubricating requirements of the conveyor. Three-way valve 16, delay valve 17, counter 18, valve 21 and a lubricant supply are driven by pressurized air (S) from a common source such as a compressor (not shown). 
     Thus, actuation on-times for the nozzles are set by controlling the pulse reset times of the counter 18, while an accumulator is employed to maintain suitable pressure levels of the delay valve 17. Hence, the counter reset times will control the time between each `on` pulse signal from the delay valve, while the delay valve and accumulator settings will control the duration of each pulse, during which time lubricant solution is applied to the conveyor 11. 
     Consequently, during the on-time of fluid valve 19, lubricant will be applied from the lubricant supply to the nozzles and then to the conveyor, depending on the duration of the pulse from the delay valve to the fluid valve; also, counter 18 will determine time intervals between each pulse. 
     If desired, branch lubricating feed nozzles can be controlled in conveyors remote from conveyor 11 by teeing several delay valves in conjunction with the counter 18. This enables a single system to control the output of a plurality of feed nozzles to various conveyors which are likely to be moving at different speeds than conveyor 11. Consequently, less expense is incurred for additional components and corresponding maintenance, and fewer personnel are necessary to control the operation. 
     The use of branch lubricating feed nozzles also enables separately applying lubricant, germicides, fungicides, etc., to a conveyor, which is particularly useful, since germicides and fungicides are frequently incompatible with lubricants, and also tend to have a shorter shelf life than the lubricants into which they would otherwise be mixed. Thus lubricant would be supplied through nozzle 12 and germicides, etc. separately through nozzle 13.