Measuring instrument for flow resistance of porous sound absorption material

Abstract

The invention discloses a measuring instrument for the flow resistance of a porous sound absorption material, which comprises a specimen tube, wherein one end of the specimen tube is of a closed structure, the other end of the specimen tube is of an open structure, and the tube wall, which is close to the closed end, of the specimen tube is at least provided with a differential pressure measuring joint and an air inlet joint. The measuring instrument is characterized in that a grid plate is supported in the radial direction at the inner wall of the middle part of the specimen tube, the outer surface of the grid plate is used for placing a specimen material, the specimen material is mainly limited in the axial direction by an annular sealing assembly which his arranged in the specimen tube and located at the outer side of the grid plate, the annular sealing assembly is provided with an air flow channel, and the annular sealing assembly is closely matched with the inner wall of the specimen tube. The measuring instrument is conducive to improving and ensuring the accuracy and the reliability of flow resistance measurement of the porous sound absorption material effectively and reliably, and is high in practicability.

Description

technical field [0001] The invention relates to sound-absorbing performance testing equipment for sound-absorbing materials, in particular to a flow resistance measuring instrument for porous sound-absorbing materials. Background technique [0002] Porous sound-absorbing materials are widely used in the sound quality design and noise control engineering of halls. It is required to match the acoustic characteristic impedance of the surrounding sound-transmitting medium, so that sound energy can enter the porous sound-absorbing material without reflection, and make the incident sound energy Most are absorbed. Therefore, it is of great significance and practical value to study and improve the acoustic properties of porous sound-absorbing materials. [0003] The acoustic properties of porous sound-absorbing materials are determined by many physical quantities, including the physical quantity of flow resistance of porous sound-absorbing materials, which can clearly reflect the m...

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Problems solved by technology

Among them, the flow resistance measuring instrument mainly used in the measurement of the water tank method, such as the "water tank method flow resistance meter" disclosed in the Chinese patent literature (publication number: CN201319029, publication date: September 30, 2009), etc., although these technologies can measure the porous The flow resistance of sound-absorbing materials can be effectively measured, but it has technical problems such as bulky, inconvenient use, poor reliability and economy, and is not practical enough.

The flow resistance measuring instrument mainly used in the measurement of the compressed air method is "an instrument for measuring air flow resistance" disclosed in Chinese patent literature (publication number: CN 104458200, publication date: March 25, 2015), etc., these Although the technology effectively reduces the structural volume and improves the convenience of use and operation, when measuring the flow resistance performance of the sample material, due to the lack of reliable and effective support and positioning structures for the sample material in the sample cylinder, Therefore, it is easy to cause the sample material to be compressed and deformed in the sample cylinder during the measurement process, which leads to inaccurate and reliable measurement results, especially when the annular gap between the sample material and the inner wall of the sample cylinder is not strictly sealed more obvious below

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