THERMAL AND SOUND INSULATION WITH A THERMAL AND SOUND INSULATION PRODUCT AND A MEMBRANE ON THE FRONT SIDE

Description

[0001] The invention relates to a thermal and acoustic insulation system for marine applications, such as ships, enabling the insulation of the metal walls of ships.

[0002] It is common practice to use mineral wool thermal insulation products, such as the Ultimate product sold by Saint-Gobain Isover, to insulate these types of walls. To improve sound insulation, a membrane is placed on the front face of the thermal and acoustic insulation product, that is, the face of the product that will face the room to be insulated (the face opposite the one facing the wall). This membrane typically has a surface density between 2 and 10 kg / m² and a volumetric density between 2000 and 2200 kg / m³ to significantly improve sound insulation. However, the major drawback of this membrane is that it is airtight, which negatively impacts sound absorption. The noise level in the rooms where the sound originates can then be significantly increased.

[0003] US2010 / 0224438 describes a multilayer insulator for an internal combustion engine, comprising at least a first layer having an airflow resistance of between 50 and 150 kNs / m 4< and a thickness of between 5 and 50 mm, a second layer having an airflow resistance of between 200 and 600 kNs / m 4< and a thickness of between 0.5 and 8 mm, the layers being connected in pairs and in contact, and an air layer between the engine and the first layer.

[0004] There is therefore a need for a thermal and acoustic insulation system, including a thermal and acoustic insulation product and a front-facing membrane, which significantly improves sound absorption without degrading sound insulation.

[0005] To this end, the invention proposes a thermal and acoustic insulation system according to claim 1.

[0006] The invention also relates to the use of the thermal and acoustic insulation assembly described above on a metal ship wall.

[0007] Other features and advantages of the invention will now be described with reference to the drawings on which: There Fig. 1 represents a cross-sectional view of the thermal and acoustic insulation assembly according to the present invention mounted on a metal ship wall.

[0008] Reference numbers that are identical across different figures represent similar or identical elements.

[0009] The invention relates to a thermal and acoustic insulation system comprising: a thermal and acoustic insulation product made of mineral wool comprising a first face, called the front face, intended to be turned towards the interior of a room, and a second face, called the back face, intended to be turned towards a wall, a micro-perforated membrane arranged on the front face of the thermal and acoustic insulation product.

[0010] The micro-perforations in the membrane allow for control of both sound absorption and sound insulation. The membrane acts as a resistive veil, enabling greater dissipation of the sound wave within the thermal and acoustic insulation material located behind it. The presence of these micro-perforations only slightly reduces sound insulation compared to a non-perforated membrane, while simultaneously improving sound absorption. The perforation dimensions and density are carefully calculated to control both sound absorption and sound insulation. A low density limits the degradation of insulation (compared to a sealed membrane of the prior art). Furthermore, the perforation dimensions are small to optimize energy dissipation through viscous friction of the air set in motion by the sound wave.Sound absorption is thus greatly improved.

[0011] There figure 1 Figure 1 shows a cross-sectional view of the thermal and acoustic insulation assembly according to the present invention, mounted on a wall 2, which is, for example, a steel or aluminum metal wall of a ship. The thermal and acoustic insulation assembly comprises a mineral wool thermal and acoustic insulation product 1 having a first face, referred to as the front face 1a, intended to face the interior of a room to be insulated, and a second face, referred to as the rear face 1b, intended to face a wall 2 of a room to be insulated. In this figure, the rear face 1b of the thermal and acoustic insulation product is placed against the wall 2.

[0012] The thermal and acoustic insulation product is made of glass wool or rock wool, composed essentially of aluminosilicate type glass fibers including aluminum oxide, Al 2 O 3, in a mass fraction between 13% and 28%.

[0013] The thermal and acoustic insulation assembly further includes a micro-perforated membrane 3 which is positioned on the front face 1a of the mineral wool thermal and acoustic insulation product 1.

[0014] The micro-perforated membrane 3 typically has a surface density between 2 and 10 kg / m². It is therefore a heavy membrane which provides good acoustic insulation to the overall thermal and acoustic insulation system.

[0015] The micro-perforated membrane 3 is a viscoelastic layer having optionally at least one of the following properties: A structural damping η, equal to tanδ and a function of frequency, which is greater than or equal to 5% regardless of frequency, and / or a Young's modulus E, also a function of frequency, which is less than or equal to 500 MPa. This "low" Young's modulus value gives the membrane a certain elasticity / flexibility, which is particularly useful for installation on ship walls.

[0016] Typically, the micro-perforated membrane 3 has an airflow resistance between 0.5 kPa.s / m and 10 kPa.s / m, preferably between 1 kPa.s / m and 5 kPa.s / m. The airflow resistance is measured according to ISO 9053.

[0017] The airflow resistance of the micro-perforated membrane 3 represents a limited capacity for air to pass through it, which is linked to the presence of the micro-perforations in the membrane. Since the airflow resistance of the micro-perforated membrane 3 ranges from 0.5 kPa·s / m to 10 kPa·s / m, it introduces energy dissipation through viscous friction of the air set in motion by the acoustic wave. Thus, absorption is significantly improved, particularly at low frequencies. If the airflow resistance is too low, the acoustic attenuation caused by internal friction is minimal, and the absorption effect provided by the membrane is weak. However, the membrane's high permeability allows the wave to be absorbed by the thermal and acoustic insulation material directly behind it. If the resistance is too high, most of the acoustic waves are reflected, and absorption is weakened.Typically, below 0.5 kPa.s / m, or even below 1 kPa.s / m, sound insulation is degraded. Above 10 kPa.s / m, there is no further gain in absorption.

[0018] The micro-perforated membrane 3 also has, for a thickness L, a perforation ratio ϕ and a perforation diameter D such that ϕD 2 < = 32η × L / (σL) where σL denotes the membrane's airflow resistance and η the dynamic viscosity of air. For a given airflow resistance, a perforation ratio / perforation diameter pair can thus be defined. The micro-perforated membrane can be perforated with micro-perforations of various diameters. The perforations can have any geometric shape, for example, circular, oblong, or slotted.

[0019] Thus, the micro-perforated membrane 3, for example, has: a perforation rate (as a percentage of hole area / total area) between 0.01 and 5%, preferably between 0.05% and 2%, or even between 0.1% and 1%, a perforation radius between 0.01 and 0.5 mm, preferably between 0.1 and 0.25 mm.

[0020] A perforation rate between 0.01% and 5%, preferably between 0.05% and 2%, or even between 0.1% and 1%, optimizes both sound insulation and sound absorption. Lower perforation rates tend towards a completely airtight membrane, while higher values ​​risk significantly degrading insulation. A perforation rate between 0.01% and 5% thus offers a favorable compromise between a significant gain in sound absorption and a very moderate loss of sound insulation.

[0021] The micro-perforated membrane 3 is preferably glued, bonded, or coupled, at least partially, to the front face 1a of the thermal and acoustic insulation product 1. The bonding or adhesion is preferably achieved by gluing, for example, in the form of dots or lines of adhesive. The entire surface of the membrane's back layer does not necessarily need to be coated with adhesive.

[0022] Furthermore, thermal and acoustic insulation product 1 typically has a density between 13 kg / m³ and 200 kg / m³, preferably between 13 kg / m³ and 100 kg / m³, or even between 24 kg / m³ and 100 kg / m³. This density range gives the thermal and acoustic insulation product sufficient mechanical strength for the intended application, namely the insulation of substantially vertical ship walls.

[0023] Thermal and acoustic insulation product 1 typically has a thickness between 10 mm and 150 mm, preferably between 15 mm and 150 mm, or even between 20 mm and 150 mm. This thickness range ensures good mechanical strength of the thermal and acoustic insulation product and sufficient absorption of sound waves for the intended application.

[0024] Preferably, the thermal and acoustic insulation product 1 has a Young's modulus between 5 kPa and 2 MPa and a damping factor between 0% and 50%. The Young's modulus and damping factor measurements are performed according to ISO 18437 and the article by C. Langlois, R. Panneton, and N. Atalla: "Polynomial relations for quasi-static mechanical characterization of isotropic poroelastic materials," J. Acoust. Soc. Am., 110:3032-3040, 2001. The Young's modulus is indicative of the acoustic insulation properties.

[0025] Optionally, the thermal and acoustic insulation assembly also includes a mineral wool facing 6, positioned on the side of the micro-perforated membrane opposite the thermal and acoustic insulation product 1, i.e., on the front face of the micro-perforated membrane 3, with the back face of the micro-perforated membrane 3 facing the front face 1a of the thermal and acoustic insulation product 1. The facing 6 is a thin layer compared to the thermal and acoustic insulation product 1. The facing 6 further improves sound absorption, particularly at higher frequencies than the micro-perforated membrane 3.

[0026] The 6 surface coating typically has a surface density between 0.01 kg / m² and 10 kg / m², preferably between 0.1 kg / m² and 5 kg / m². This range of surface density gives the 6 surface coating acoustic insulation properties.

[0027] The surface coating 6 typically has a density between 20 kg / m³ and 200 kg / m³, preferably between 30 kg / m³ and 150 kg / m³, or even between 30 kg / m³ and 90 kg / m³. This density range gives the surface coating 6 its mechanical strength properties.

[0028] The 6-layer surface typically has a thickness between 0.5 mm and 20 mm, preferably between 5 mm and 15 mm, or even between 5 mm and 15 mm. This density range gives the 6-layer surface its mechanical strength and acoustic absorption properties.

[0029] According to the embodiment shown in the Figure 1 The assembly formed by the thermal and acoustic insulation product 1 and the micro-perforated membrane 3 is fixed to the metal wall 2 by means of needles 5 and washers 4, the needles 5 passing through the washers 4, the micro-perforated membrane 3 and the thermal and acoustic insulation product 1, and being embedded in the wall 2. The surfacing 6, when present, can also be held by the needles 4 and washers 5 or, as shown in the figure 1 , be glued over the micro-perforated membrane. The coupling of the thermal and acoustic insulation assembly to the metal wall 2 can be done by any other known method for fixing membranes to insulation products.

[0030] Three sets of thermal and acoustic insulation were tested in sound absorption and sound insulation: a first reference assembly comprising a thermal and acoustic insulation product and a waterproof membrane; a second assembly comprising the same thermal and acoustic insulation product and a micro-perforated membrane according to the invention; a third assembly comprising the same thermal and acoustic insulation product, a micro-perforated membrane according to the invention and a surfacing.

[0031] The thermal and acoustic insulation product common to the three thermal and acoustic insulation sets is a mineral wool panel from the Ultimate brand by Saint-Gobain Isover, with a density of 24 kg / m³ and a thickness of 50 mm.

[0032] The airtight membrane of the first thermal and acoustic insulation system has an airflow resistance of 70 kPa.s / m. This is the SeaProtect dB Flex Alu membrane from Saint-Gobain Isover.

[0033] The micro-perforated membrane used in the second and third thermal and acoustic insulation systems is the same SeaProtect dB Flex Alu membrane from Saint-Gobain Isover, but with perforations. After perforation, it has an airflow resistance of 0.640 kPa·s / m, a thickness of 1.7 mm, a surface density of 3 kg / m², a perforation rate of 0.4%, and a micro-perforation radius of 0.319 mm. The micro-perforated membrane has a surface density of 3.25 kg / m².

[0034] The surface coating for the third thermal and acoustic insulation system is the Ultimate brand coating from Saint-Gobain Isover. It has a surface density of 0.36 kg / m², a density of 24 kg / m³ and a thickness of 15 mm.

[0035] The first thermal and acoustic insulation set has a sound absorption αw of 0.05 and a sound insulation Rw of 51 dB.

[0036] The second thermal and acoustic insulation set has a sound absorption αw of 0.25 and a sound insulation Rw of 50 dB.

[0037] The third thermal and acoustic insulation set has a sound absorption αw of 0.65 and a sound insulation Rw of 51 dB.

[0038] Sound absorption and sound insulation were measured on the three products. Sound absorption αs was measured according to ISO 354. The αw indicator was then calculated according to ISO 11654.

[0039] Acoustic insulation is measured according to ISO 10140-2. The Rw indicator is then calculated according to ISO 717-1.

[0040] A gain in sound absorption (αw) of 0.2 and a loss in sound insulation (Rw) of -1dB was observed between the second thermal and acoustic insulation set (according to the invention) and the first thermal and acoustic insulation set (reference), and a gain in sound absorption (αw) of 0.6 and no loss of sound insulation between the third thermal and acoustic insulation set (according to the invention) and the first thermal and acoustic insulation set (reference).

[0041] It has therefore been shown that the thermal and acoustic insulation assembly according to the invention makes it possible to greatly improve sound absorption while barely degrading, or not at all, the sound insulation, an effect which is even more pronounced when the surface is also present.

[0042] The invention also relates to the use of the thermal and acoustic insulation assembly according to the invention on a metallic wall, made of steel or aluminum, of a ship in order to greatly improve sound absorption while hardly degrading, or not at all degrading, the sound insulation of a part of the ship.

Claims

1. A thermal and acoustic insulation assembly comprising: - a thermal and acoustic insulation product (1) of mineral wool comprising a first face, called the front face (1a), intended to be directed towards the interior of a room, and a second face, called rear face (1b), intended to be directed towards a wall (2), - a microperforated membrane (3) arranged on the front face (1a) of the thermal and acoustic insulation product (1), the thermal and acoustic insulation assembly being characterized in that the microperforated membrane (3) is a viscoelastic layer and in that the microperforated membrane (3) has, for a thickness L, a perforation degree ϕ and a perforation diameter D such that ϕD2 = 32η × L / (σL), where σL represents the airflow resistance of the membrane and η the dynamic viscosity of the air.

2. The thermal and acoustic insulation assembly according to claim 1, wherein the microperforated membrane (3) is a viscoelastic layer, optionally having: - a structural damping η which is greater than or equal to 5% irrespective of the frequency, and / or - a Young's modulus E of less than or equal to 500 MPa irrespective of the frequency.

3. The thermal and acoustic insulation assembly according to claim 1 or 2, wherein the microperforated membrane (3) has an airflow resistance of between 0.5 kPa.s / m and 10 kPa.s / m, preferably between 1 kPa.s / m and 5 kPa.s / m.

4. The thermal and acoustic insulation assembly according to one of claims 1 to 3, wherein the microperforated membrane (3) has: - a perforation degree of between 0.01 and 5%, preferably between 0.05% and 2%, even between 0.1% and 1%, - a perforation radius of between 0.01 and 0.5 mm, preferably between 0.1 and 0.25 mm.

5. The thermal and acoustic insulation assembly according to one of claims 1 to 4, wherein the microperforated membrane (3) has a surface density of between 2 and 10 kg / m2.

6. The thermal and acoustic insulation assembly according to one of claims 1 to 5, wherein the thermal and acoustic insulation product (1) has a density of between 13 kg / m3 and 200 kg / m3, preferably between 13 kg / m3 and 100 kg / m3, even between 24 kg / m3 and 100 kg / m3.

7. The thermal and acoustic insulation assembly according to one of claims 1 to 6, wherein the thermal and acoustic insulation product (1) has a thickness of between 10 mm and 150 mm, preferably between 15 mm and 150 mm, even between 20 mm and 150 mm.

8. The thermal and acoustic insulation assembly according to one of claims 1 to 7, wherein the thermal and acoustic insulation product (1) is essentially composed of aluminosilicate type glass fibers.

9. The thermal and acoustic insulation assembly according to one of claims 1 to 8, wherein the microperforated membrane (3) is glued or bonded or mated at least in part to the front face of the thermal and acoustic insulation product.

10. The thermal and acoustic insulation assembly according to one of claims 1 to 9, further comprising a surfacing (6) of mineral wool arranged on the face of the microperforated membrane (3) opposite the thermal and acoustic insulation product (1).

11. The thermal and acoustic insulation assembly according to claim 10, wherein the surfacing (6) has a surface density of between 0.01 kg / m2 and 10 kg / m2, preferably between 0.1 kg / m2 and 5 kg / m2.

12. The thermal and acoustic insulation assembly according to claim 10 or 11, wherein the surfacing (6) has a density of between 20 kg / m3 and 200 kg / m3, preferably between 30 kg / m3 and 150 kg / m3, even between 30 kg / m3 and 90 kg / m3.

13. The thermal and acoustic insulation assembly according to one of claims 10 to 12, wherein the surfacing (6) has a thickness of between 0.5 mm and 20 mm, preferably between 5 mm and 15 mm, even between 5 mm and 15 mm.

14. The use of a thermal and acoustic insulation assembly according to one of claims 1 to 13 on a ship's metal wall.