Pump-based systems:
like Unist’s Coolubricator and Serv-O-Spray move the fluid using a small pneumatic pump. The pump allows precise control of the fluid output though adjustments of its stroke length and frequency. The positive displacement design ensures that exactly the same volume of lubricant is metered out with each stroke. It is the most precise and repeatable fluid delivery approach and makes hitting the lubricant ‘sweet spot’ for individual applications much easier. Most pump-based systems have a modular design that allows multiple outputs, each with their own pump, to be combined in a single applicator.This makes for easy customization based on the needs of any particular machine. Pump-based systems do have moving parts which can wear over time. However, when a quality lubricant such as Coolube is used, these pumps provide years of trouble-free performance. In fact, Unist system customers who use only Coolube in their systems enjoy a lifetime warranty on their system’s positive-displacement pumps.
Pressure-based systems:
use a pressurized tank to force the lubricant through the system. The amount of lubricant delivered is controlled through a separate metering system. Higher quality pressure-based systems allow separate adjustment of the tank pressure, the output airflow and the amount of oil injected into the airflow. These systems often allow several outputs to be connected and regulated from a single tank. Pressure-based systems produce a consistent output stream and have fewer moving parts than pump-based systems. However, even with a regulator, the pressure will vary some and most fluid’s properties change with temperature. Like a venturi system, it is difficult to do precise adjustment of the amount of lubricant that is delivered. Furthermore, the number of outputs is limited by the pressure drop inherent in the design.
Venturi systems:
are the simplest and use the Venturi principle to siphon fluid from a reservoir. These types of systems create aerosol particles of approximately 0.5 μm to 5 μm. Venturi systems are single-channel only and have almost no moving parts. This makes them simple and reliable. However, external environmental conditions and variations in the incoming airflow directly affect the output; so, although reliable, they are not particularly precise. As is true in all single line systems, a venturi-based system is slow to react to changes in settings.