The aerosol quantity provided at the tool and the oil-air ratio results from a superimposition of several different aerosol generators in the unit. During the running process, individual aerosol generators continuously deactivate/activate themselves and automatically regulate their output as required on the basis of an (adjustable) dosing characteristic curve (see graphic below). A purely pneumatic regulating system is installed for this purpose. The measured variable is the tool- and process-dependent aerosol dynamic pressure, which adjusts itself in particular as a function of the current lubrication conditions (too much/too little) and the cooling channel diameter (small/large). The control system operates continuously.

For simplified illustration, three cases will be considered here as examples:

In the case of a tool with large cooling channels (x-axis, left), a low aerosol dynamic pressure occurs at the tool. The aerosol generators work according to the characteristic curve in the operating case ① with a large differential pressure (between mains pressure P_N and dynamic pressure) and consequently supply an increased aerosol quantity suitable for the tool.

The operating case ② (x-axis, center) occurs, for example, with a tool with a medium cooling channel diameter (e.g. 1 mm). In principle, smaller cooling channels cause a reduction in the aerosol volume flow. In order to still achieve sufficient lubrication, the aerosol pressure and the oil content in the aerosol are automatically increased overproportionally in accordance with the dosing characteristic, so that the lower volume flow is compensated.

Finally, a very small tool is considered with the operating case ③. For this, an additional mode is activated by a solenoid valve through a pressure switch, whereupon a special aerosol generator is operated in a pulsating manner. Intermittent operation of the aerosol generator ensures ideal lubrication of a wide range of very small tools.

In 1995, the first aerosol boosters were produced with the AB250 LC. It has 3 aerosol generators of different sizes which can be activated individually or in groups. In many applications and extensive tests, the optimum setting for each case was determined and documented together with our customers for a wide range of tools. These results formed the basis and the benchmark for the characteristic control curve of the AB250 Standard and AB250 Automatic. In a figurative sense it was the replacement of a manual gearbox by an automatic gearbox which automatically shifts into the most suitable gear.

During initial commissioning of your new AB 250, the standard characteristic curve can be fine-tuned for your individual process, if necessary, by means of the two pressure regulators P₁ and P₂ and the two switching points of the hysteresis pressure switch SP₁ and SP₂. The result: the appropriate lubricant dosage is automatically set for each tool used - without the need for external control or internal electronics. To control the devices with TKM self-regulation, all that is needed after commissioning is a switching signal to switch the lubrication on/off.