ACOUSTIC SCREEN FOR SELF-TWISTING SPINNING MACHINES Russian patent published in 2018 - IPC D01H11/00 

FIELD: acoustics.

SUBSTANCE: invention relates to industrial acoustics, for example, directed at noise reduction of spindle drive of spinning machines. Acoustic screen for self-twisting spinning machines contains a soundproof cover that seals the aerodynamic torsion device (ATD) assembly together with the original product, the exhaust roller and the belt, cover is lined with sound-absorbing material and an acoustically transparent film, the drawer roller with a total length L and outer diameter D has at least three grooves with a diameter d: central groove with a length L₂ and lateral grooves of length L₁, while the ratio of the outer diameter D of the drawer roller to the diameter d of the grooves lies in the optimum range of values D/d=1.04…1.05, and the ratio of the total length L of the roller to the length L₂ of the central groove lies in the optimum range of values L/L₂=4.3…4.4, and the ratio of the length L₂ of the central groove to length L₁ of the lateral grooves lies in the optimum range of values L₂/L₁=2.0…2.2, sound-absorbing material on the inner surface of the cover is made on the basis of aluminum-containing alloys, followed by their filling with titanium hydride or air with a density within 0.5…0.9 kg/m³ with the following strength properties: compressive strength within 5…10 MPa, bending strength within 10…20 MPa, or in the form of crumbs of solid vibration cushioning materials, for example, elastomer, polyurethane, placed in a shell of a sound-transparent material, the size of crumb fractions lies in the optimum range of values of 0.3…2.5 mm. According to the invention, the lining of the sound-absorbing cover is formed with resonant inserts and contains a smooth and perforated surface between which a composite sound-absorbing layer of complex shape is placed, which is an alternation of solid areas and hollow sections, framework of which is made of a rigid sound-absorbing material, the hollow sections are formed by prismatic surfaces that have a parallelogram shape in the cross section parallel to the plane of the drawing, the internal surfaces of which have a toothed structure, tops of the teeth face the prismatic surfaces, and prismatic surfaces edges are fixed respectively on the smooth and perforated surfaces, wherein the cavities formed by the smooth and perforated surfaces, between which a combined sound-absorbing layer is located, are filled with a soft sound-absorbing material, and cavities of hollow sections formed by prismatic surfaces are filled with a foamed polymer, for example polyethylene or polypropylene, hollow cavities formed by prismatic surfaces are connected by resonant holes and with cavities formed by smooth and perforated surfaces, between which a composite sound-absorbing layer is located.

EFFECT: technical result is an increase in the efficiency of noise suppression due to the expansion of the frequency spectrum in resonant modes by introducing resonant elements into the lining that expand the spectrum of the noise suppression frequencies.

1 cl, 4 dwg