Most Dust extraction systems are designed with a big centralised fan connected to a main duct that spreads out to connect all extraction points.
This happens in all type of industries, involving the production of dust, fumes, or vapours, such as woodworking, metalworking, pharma, plastics and polimers, food and beverage, chemicals and all sorts of waste.
The common way to install extraction, offers air flow to all machines, independently if a specific extraction point is demanding extraction or not. Fans are run on their top power all the time, without consideration of the real need of the system. We have collected data for over 18 years now, in hundreds of systems, and hardly there is a simultaneous demand of extraction in more than 70% of extraction points, and the most common situation is around 50%
The consequence is that the fan uses power from the line to generate airflow to offer extraction even to a number of points that are not requesting it. And you pay for that electrical power, to generate wasted air flow. Basically, you are wasting your money.
HOW DOES DESA WORK
The way the system drives the fan speed and torque is the through the POWER UNIT (which will have an inverter fitted inside among all other things). This will be fitted close to the fan and will manage the fan. It will also have a manual switch to disengage mechanically the DESA in case of failure, assuring that you will never stop your manufacturing line for reasons depending from a DESA malfunction. The POWER UNIT will return to the DESA unit all the necessary data regarding the fan and the power consumption, heat and possible problems and related savings, so that DESA can apply its patented algorithm and determinate always the right volume and pressure needed by the system.
When the main switch starts the extraction systems, DESA will immediately activate the implosion protection dampers, and start reading the extraction demand from each machine. It will consequently operate and open the necessary extraction damper and set the POWER UNIT to the correct working point.
Once a machine shows a demand for extraction, the damper will open immediately (no delays with DESA) and generate the proper air flow for the specific machine. Same will happen for all machines in demand of extraction in the workshop.
DESA can operate in automatic mode (as described) or in manual (SAFE) mode. Manual mode lets the operator choose what damper to open and what set point to use.
The SAFE mode is operated with a mechanical switch and mechanically opens all dampers and sets the fan to top speed. This is very important, as it would not require electrical connection to operate this safety procedure, therefore fail in case of electrical breakdown, with DESA you can always run safe mode, as its setup is completely mechanical and not electrical. All dampers and fan are “normally open” in case of breakdown.