The danger of fumes and micro-dusts produced during metal polishing is known to both industry operators and the authorities responsible for diffuse emissions.
In this article we present a very effective solution developed for an important manufacturing company that has expertly invested in the health of its employees and in the cleaning of the work area.
The extraction of welding fumes and grinding dust and polishing metals generated during the various metalworking activities, by suction close as possible to the source of pollution, as required by regulations for the safety of operators and the working environment.
The customer requires a dust suction system that guarantees working flexibility considering that the welding and grinding stations can work at 100% but in some periods even at 30% of their capacity. In operational terms it means designing a system that works with the same efficiency in a flow range from 29000 mc/h to the desired reduction, without waste of electricity.
From a technical point of view the challenge was above all linked to the correct suction of the polishing dust produced by fixed workstations that disperse micro-dust in a high-speed environment, difficult to capture using the classic systems such as suction arms or hoods.
The customized design and installation of a suction plant with dust collection and fine polishing dust on each individual workstation, has been carried out through suction walls with lateral and upper containment, in order to optimize the flow.
This solution effectively contains airborne dust, protecting the respiratory tract of operators and machinery.
The various suction stations are connected to each other by a network of galvanized pipes with circular cross-section, to a cartridge filter with centrifugal fan with simple suction positioned outside the production room. An Industry 4.0 compliant electrical panel with inverter and pressure reading inside the ducts will regulate the actual suction capacity of the system and consequently the absorbed power of the fan, for maximum energy saving.
Design and development
After careful analysis of the client’s production needs, the contemporaneity of the work, and the production layout, our technical office has developed the project of the suction system articulated in the following points:
- Sizing of the correct air velocities both during the phases of dust and fumes extraction and in the suction channels;
- Calculation of the overall load losses of the circuit according to the pipe path and the filter used;
- Selection of the type of walls, benches, and suction arms, in order to facilitate the work of operators as much as possible and at the same time capture fumes and dust as close as possible to the source;
- Design and construction of all the special fittings made to measure in order to be integrated in the present plant context
- Sizing of filter and fan seasoning the overall capacity of the system and the pressure drops of the connected systems.
- Design of the electrical panel 4.0 for the command and control of the system, including the automatic regulation of the fan revolutions with inverter system that changes in real time the working range according to the number of workstations used, for maximum energy savings.
Reference standards for suction systems
D.lgs. n. 81 of 2008 “Protection of health and safety in the workplaces” which replaced the precedents in this field such as D.P.R. n. 303/56 “General rules for occupational hygiene”, D.P.R. n. 547/55 “Norms for the prevention of occupational accidents” and Legislative Decree No. 626/94 “Implementation of EEC directives concerning the improvement of the safety and health of workers at work” the famous “626”.
Compliance of the suction to industry 4.0
To comply with Industry 4.0, the dust suction system must be controlled by computerized systems or managed by appropriate sensors and drives. For this specific case, the following features have been implemented that have allowed the customer to immediately deduct 50% of the cost of the plant.
- Automatic turn control of the fan with an inverter, to reduce energy absorption in case the system is underused
- Control of the degree of clogging filters with real-time warning of the different thresholds and alarm sent via e-email to maintenance service
- Remote management and optimized for integrated systems, with indication of any anomalies.
- Control and signaling anomalies or threshold levels of all possible sensors in the suction system, such as tribometric probes, rotovalvole, exhaust augers or fire sensors.