Lubricants: Proactive SPALs
There are many advantages to using single-point automatic lubricators, but they need to be maintained “proactively.”
Many manufacturers have lube programs that were not proactively planned and implemented, but assembled piecemeal over many years with the addition of new equipment, processes and personnel. Not surprisingly, there are problems.
Single-point automatic lubricators (SPALs) are of particular concern because there is less obvious control and observation of whether too little or too much lubricant is applied, or if it’s reaching critical parts.
Single-point lubricators are a niche type but used widely in cement and steel mills, pulp and paper mills, power plants, the mining industry, and in food and beverage plants.
Mike Deckert, vice-president of FLO Components Inc., an automatic greasing systems specialist based in Mississauga, Ont., outlined compelling reasons for using SPALs to members of the Hamilton Section of the Society of Tribologists and Lubrication Engineers (STLE).
Deckert, STLE’s section president, said they provide continuous oil or grease over a set period of time and allow re-lubrication while the machine is running – obvious advantages. In addition, installation costs are much lower than those for central systems, it’s easy to add more lubrication points as the system expands, and SPALs are ideal for hard-to-reach locations for one-point applications.
There are different types of SPALs. Spring-activated units use spring pressure on a piston to dispense lubricant, and rely on back-pressure from the bearing for the dispense rate.
Gas-charged dispenser types work like Alka Seltzer. They use gas pressure on a piston to dispense lubricant with settings from one to 12 months. They have large reservoirs – 60 to 500 cc – but there is a drawback: they are very susceptible to ambient temperature.
Gas-electromechanical activated lubricators use a motor drive on a piston to dispense the lubricant and can be wired into machine electrics. One type is electrochemical-activated SPALs that work with an electrochemical cell and an electrolyte. They have time selector switches, resistors and an electronic circuit board; a bellow gas chamber; piston and lubricant reservoir; a mounting nipple; an O-ring; and an outer plug. They’re battery-operated but have a shelf life of only one year.
SPALs have red and green LED lights for troubleshooting. When the green light is blinking every 15 seconds, the operation is okay. A red light blinking every eight seconds indicates malfunction or an error. When both the green and the red light are blinking every three seconds, the unit is empty. A continuous constant red light indicates the VARIO is discharging.
Deckert outlined some options. Grease reservoirs are refillable on some units and remote lines can be used, depending on lubricant viscosity and temperature.
Suppliers have many accessories to meet various requirements. SPALs are great if you use them correctly, use check valves for oil applications, and make sure that excess lubricant doesn’t enter the motor housing because of weak seals inside the bearing cavity.
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