Patent FR-2778781-A1 (FR)
Title: Soundproof tunnel as acoustic shrouding structure for lines of looms
Inventor: PETRELLI FRANCO
IPC: B08B5/04
Filed: 1998-05-12
Abstract: The system to contain the noise from machinery (4) in production lines (3), has a structure (1) to act as an acoustic shield for the work spaces and/or access (8) on site between the machine lines. The structure has at least two soundproof walls (5) placed along the machine lines (3), with moving soundproof panels (12) at the sites of the machines (4). The walls support a soundproof roof (6), to form a soundproof tunnel for the machine lines. The moving panels (12) are of a plastics and soundproof material, which reduces noise emissions to at least 15 decibels and which has a transparency of at least 30%. The moving panels (12) are flexible, rigid or semi-rigid. In a semi-rigid structure, they are formed by a number of rigid soundproof slats or strips, hinged together to form a panel. The soundproof walls are formed by fixed soundproof panels (11), at sections along the machine lines, between the moving panels. The fixed panels are of a soundproof plastics material, or are of natural materials such as from cellulose or recycled paper, natural rubber, or a combination of cellulose and plastics as a closed-cell foam layer.  The fixed soundproof panels have an exterior noise absorbent layer and an inner noise insulation layer. The noise absorbent layer is a perforated board with a cellulose material base, a metal grid and a layer of synthetic closed-cell foam and/or a layer of plastics. The insulation layer is a perforated cellulose board with a metal grid and/or a plastics layer. The noise insulation and absorbent layers are separated by an intermediate layer of lead to increase the acoustic insulation effect. The cellulose insulation board has a thickness of 0.25-3.0 mm, its plastics or foam layer is 1-15 mm thick, and the rubber layer has a thickness of 1-10 mm. The intermediate lead layer is 0.5-3.0 mm thick. The moving panels are fitted with rollers, and movement mechanisms give them lateral or vertical sliding movements, such as by powered racks and pinions or continuous worm screws and worm gears. The moving panels (12) have cleaning systems to remove dust and/or condensation which clings to them through static electricity, using revolving brushes and suction air jets at the surfaces with a central dirt collection station. Some fixed soundproof walls are extended, at the outer tunnel walls, using lateral soundproof panels on the ground, to act as sound barriers between the separate machines in the production line. Moving soundproof panels can be moved in and out of position at the tunnel ends, to seal or open them. An automatic control rolls the moving panels clear of a machine on a stoppage or at the end of its production cycle. The operation is triggered by a sensor at the machine using conventional systems such as electric, electromagnetic, magnetic, or a light beam. The moving panels are also shifted automatically when the approach of an operative is detected using a visible or infrared light beam. The movement detection sensor is within the soundproof tunnel, at a sufficient height in relation to the ground level, to register the approach of an operative at a machine and open the moving panel at that machine. The moving soundproof panel can also be opened and closed manually and/or with an acoustic or visual alarm to indicate the panel movement. The soundproof walls of the tunnel are supported by vertical posts (9) at the ground and/or horizontal beams (10) held in place at the upper level (7) of the walls by the posts. The posts also lock together neighboring sections of the soundproof wall. The fixed soundproof panels are held in place at the ground by mounting brackets at their lower sections, with socket extensions at the brackets. The fixed panels have a guide for the lateral edges of adjacent moving panels for their movement. The soundproof walls are at a gap of 3.8 m apart, with a height of at least 2.8 m.