"How do you spray-lubricate an open gear? Are nozzles commonly available for this? What air pressure is ideal? What is the best distance between the nozzle and application area? Is spray lubrication the best way to lubricate an open gear?"
When it comes to open gears, spray lubrication is a common practice. However, it isn't the only option. A variety of greases are specially formulated to work on open gears. That said, there are some key practices to follow when using a spray system on an open gear.
As with any lubrication system, it is important to verify that the appropriate volume and type of lubricant are being used. You must also ensure that the lubricant stays in place and is of the correct viscosity.
The distance between the gear teeth and the spray system's nozzles can vary greatly. Sometimes they may be placed as close as 2 inches, while in other cases a distance of 8 inches is desirable. It depends on the speed of the gear, the gear size and the spray nozzle in use.
A variety of nozzles are available, with each offering a distinct spray pattern and requiring a different air pressure. Selecting a spray pattern is one of the more critical considerations for this application. While most nozzles do a good job of atomizing the lubricant, you must make certain that the spray pattern coats the gear surface prior to the teeth meshing. This may require several nozzles. The entire width of the gear must be sufficiently covered with lubricant, and overspray should be minimized.
It is a good practice to routinely inspect any spray system for proper operation. This includes confirming that the nozzles are actually spraying, there is adequate air pressure and there is lubricant in the reservoir. The nozzles tend to clog with debris or wax in some cases. Any clogging of the nozzles can have adverse effects on the spray pattern and the quality of lubrication that is occurring on the gear.
Spray lubrication offers a great way to lubricate open gears, but the same rules apply as with any lubrication practice. The system will only be as good as it is installed and maintained. Many excellent systems have failed due to lack of maintenance or inspections. With proper maintenance, these systems can provide increased reliability and decrease the manpower required to lubricate the gears manually.