Mining Equipment

Mining

May 22,2002

Take a few moments and ask yourself these five questions about your conveyor:

1. Do you experience surging of the conveyor, causing the parts to sway back and forth on the line
2. Does your conveyor squeak or grind?
3. Does your chain snap, pop or bind as it goes around turns?
4. Do the bearings on your conveyor roll or slide along the rail?
5. Do you experience rejects due to dirt contamination or debris falling from the conveyor?

If the answer to any of these questions was yes, you need to look at your conveyor maintenance program -- specifically your lubrication and cleaning methods.

Lubricating Equipment
For industrial conveyors, an automatic conveyor lubricator is the equipment of choice. There are two general types of conveyor lubricators: centralized systems and self-contained systems.

The central system uses two separate components. A central plumbing reservoir is set on the floor and supplies power and lubricant to the lubricator(s). Advantages of this system include the ability to supply multiple lubricators from one source and ease of filling the reservoir.

Self contained lubricators consist of a tank, pump and lubricator all in one package. Advantages include lower cost and easy installation. Lubricators should be mounted between the load/unload station of the conveyor where there are no parts on the conveyor to get contaminated if dripping should occur. Another possibility is to mount the lubricator prior to washing. The advantage to this is the washer cleans the part right away if a drop of lubricant gets on it, preventing a defect in the finish.

Mounting a lubricator prior to the drive is acceptable only when there are no other parts on the conveyor at that location. If there will be parts at that location, it is advisable to consider other options that will not interfere.

The lubricator is controlled by a microprocessor that is activated when a bearing or a chain pin pass through a sensor. The microprocessor is programmed to dispense lubricant into the wear points of the conveyor chain. The microprocessor controls the frequency of lubrication as well as the precise amount of lubricant applied.

The high degree of control allows the user of the automatic conveyor lubricator to prevent both under-lubrication and over-lubrication of the conveyor, reducing both chain wear and part contamination by the lubricant. E-Prom memory retains the lubrication program in the case of a power failure.

Conveyor Lubricants
High quality lubricants are required to survive the rigors of the industrial environment. These lubricants must have the following properties:

1. They should not attract dirt, powder or other abrasives;
2. They should prevent friction, seizing and rust;
3. They should penetrate into wear points;
4. They should form a film to reduce friction in the wear points;
5. They should have minimal dripping when applied.

The use of proper lubricants and lubricating devices reduce chain wear as well as decrease rejects from lubricant contamination of the parts during production. Penetrating lubricants containing solid type lubrication agents, such as moly-disulfide, graphite and synthetics are the best choices for these applications.

The lubricant, when properly applied, penetrates into the wear points of the chain and leaves behind a thin film of lubricant.

This application is readily accomplished by automatic conveyor lubricators, and helps eliminate dripping by allowing the precise control of the amount and location of applied lubricant.

Grease can be used successfully to lubricate the sealed bearings on an I-Beam conveyor. Grease selection should be based on operating temperature, conveyor speed, time in the oven and weight.

There are synthetic greases on the market that will stand up to the rigors of the average finishing system, but be sure they do not contain silicone.

Brush Cleaning Systems
In conjunction with proper lubrication, much benefit can be gained through the use of conveyor brush cleaners. There are two kinds of brushes available.

Chain and Trolley Cleaning Brushes:
These brushes mount on the rail and clean the chain and bearings. The chain and bearings are constantly being exposed to paint, powder, chemicals and dirt as they move through the system. Eventually, these contaminants build up to a point and start to fall off, causing rejected parts. It is advisable to mount chain cleaners prior to the washer so any debris falling of the brush will be washed off. Normally, brushes are used during non-production; however, some users run brushes constantly with acceptable results.

Beam and Channel Sweeps:
These brushes are mounted or attached to the chain itself and are used to “sweep” the rail or beam of debris and build-up. This helps eliminate the debris falling onto parts. These brushes, used together with proper conveyor lubrication, help eliminate parts contamination and reduce rejects.

Preventative Maintenance
It is recommended to have a regular service schedule to monitor the condition of the conveyor and to assure the proper operation of the conveyor lubrication and cleaning equipment.

By ensuring that the equipment is operating correctly and the proper lubricants are being applied, rejects and downtime can be greatly reduced. Service can be contracted with conveyor lubricator suppliers or done by plant personnel. Remember, conveyor maintenance doesn’t cost, it pays! When done properly, a systematic approach to conveyor maintenance will help your company by:

• Reducing conveyor wear
• Lowering reject rates
• Improving product quality
• Increasing operating efficiency