Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
  • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
  • H04R1/2803—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means for loudspeaker transducers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
  • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
  • B01D53/0407—Constructional details of adsorbing systems
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
  • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
  • B01J20/16—Alumino-silicates
  • B01J20/18—Synthetic zeolitic molecular sieves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
  • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
  • B01J20/16—Alumino-silicates
  • B01J20/18—Synthetic zeolitic molecular sieves
  • B01J20/183—Physical conditioning without chemical treatment, e.g. drying, granulating, coating, irradiation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
  • B01J20/26—Synthetic macromolecular compounds
  • B01J20/261—Synthetic macromolecular compounds obtained by reactions only involving carbon to carbon unsaturated bonds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28002—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their physical properties
  • B01J20/28004—Sorbent size or size distribution, e.g. particle size
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28002—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their physical properties
  • B01J20/28011—Other properties, e.g. density, crush strength
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
  • B01J20/28016—Particle form
  • B01J20/28019—Spherical, ellipsoidal or cylindrical
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
  • B01J20/28016—Particle form
  • B01J20/28021—Hollow particles, e.g. hollow spheres, microspheres or cenospheres
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
  • B01J20/2803—Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28054—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J20/28078—Pore diameter
  • B01J20/2808—Pore diameter being less than 2 nm, i.e. micropores or nanopores
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28054—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J20/28078—Pore diameter
  • B01J20/28085—Pore diameter being more than 50 nm, i.e. macropores
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/30—Processes for preparing, regenerating, or reactivating
  • B01J20/3042—Use of binding agents; addition of materials ameliorating the mechanical properties of the produced sorbent
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/30—Processes for preparing, regenerating, or reactivating
  • B01J20/305—Addition of material, later completely removed, e.g. as result of heat treatment, leaching or washing, e.g. for forming pores
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/30—Processes for preparing, regenerating, or reactivating
  • B01J20/3078—Thermal treatment, e.g. calcining or pyrolizing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/30—Processes for preparing, regenerating, or reactivating
  • B01J20/3092—Packing of a container, e.g. packing a cartridge or column
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
  • C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
  • C01B39/026—After-treatment
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
  • C08J9/0066—Use of inorganic compounding ingredients
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/106—Silica or silicates
  • B01D2253/108—Zeolites
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/106—Silica or silicates
  • B01D2253/108—Zeolites
  • B01D2253/1085—Zeolites characterized by a silicon-aluminium ratio
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/25—Coated, impregnated or composite adsorbents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/30—Physical properties of adsorbents
  • B01D2253/302—Dimensions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/30—Physical properties of adsorbents
  • B01D2253/302—Dimensions
  • B01D2253/308—Pore size
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/30—Physical properties of adsorbents
  • B01D2253/302—Dimensions
  • B01D2253/311—Porosity, e.g. pore volume
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/30—Physical properties of adsorbents
  • B01D2253/34—Specific shapes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/10—Single element gases other than halogens
  • B01D2257/102—Nitrogen
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/10—Single element gases other than halogens
  • B01D2257/104—Oxygen
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/80—Water

Definitions

• the present invention relates to a material comprising an assemblage of highly spherical particles without protrusions and a specific porosity for fast gas sorption for the use in loudspeakers.
• spheres In contrast to such irregular formed granules, spheres have a number of advantages.
• the spheres exhibit a higher degree of mechanical robustness, as described in (Krasii, B. V., V. B. Maryshev, and T. S. Kustova. "Comparison of mechanical strength of reforming catalysts of different geometry.” Catalysis in Industry 1.4 (2009): 364-366. or US20100196213).
• the spheres do not contain sharp edges, which can lead to abrasion and dust formation as described in (ASTM D 4058-87, "Standard Test for Attrition and Abrasion of Catalysts and Catalyst Carriers") and show an enhanced flowability (no congestion during dosing - see e.g. US4687672). Furthermore, with monodisperse spheres, reproducible and dense packings with defined void spaces of a given volume are possible. In particular the ability of the spheres to fill irregular formed geometries is advantageous.
• the disclosure teaches the synthesis of highly spherical particles with a defined porosity and a high abrasion resistance for use in loudspeakers.
• FIG 1 Impedance curves recorded as described in example 5.
• FIG 2 SEM micrographs of particles produced as described in example 2.
• FIG 3 and FIG 4 SEM micrographs of particles produced as described in example 2 for roundness classification.
• the mean diameter is 1 mm.
• FIG 5 Scheme of the double nozzle used in example 3.
• FIG 6 Scheme of the pressurized-air device used in example 3.
• FIG 7 Set of SEM micrographs of the spheres produced as described in example 3.
• FIG 8 Set of SEM micrographs of the spheres produced as described in example 4.
• FIG 9 Cumulative pore volume distribution measured by mercury intrusion.
• FIG 10 Impedance curves of material synthesized in example 3 and 4 recorded as described in example 5.
• FIG 11 Image of a fragmented sphere produced as described in example 4 showing the hollow core.
• a fixed bed comprising a plurality of spheres having a smaller diameter exhibit a higher pressure drop across the fixed bed than a fixed beds with spheres of a larger diameter.
• the pressure drop should be as low as possible across the fixed bed, since the fixed bed should be accessible in bulk to high variations in the pressure of sound wave. It would therefore be contradictory to reduce the sphere diameter too much.
• the spheres with a smaller diameter might hinder the sound waves travelling through the entire bed, thus leading, by effectively “flattening" pressure variations, to a reduction in the desired effect of virtually increasing the back volume.
• FIG 1 A was recorded with an empty cavity (no spheres), FIG 1 B with the spheres of 0.4 mm diameter and FIG 1 C with spheres of 1 mm.
• the spheres were synthesized as described in example 1 and 2 and exhibited the same internal porosity.
• the incorporation of the spheres resulted in a shift of a resonance frequency to lower values in both of the cases shown in Fig. IB and 1C.
• the resonance frequency shift was higher in the case of the bigger spheres and the dampening (broadening of the resonance peak) was lower.
• the diameter of the spheres should be kept as large as possible.
• a larger sphere leads to higher diffusion path lengths inside an individual one of the spheres. Furthermore, the surface area in relation to the mass of a sphere to be accessed by intruding gas molecules is lowered. In order to compensate these negative effects on the accessibility of a sphere, it is desirable to control the porosity of the individual spheres and to introduce macropores within the spheres. Such macropores are also described e.g. in US8794373B 1.
• a well-known, cost effective and versatile method to manufacture molded paddings with controlled porosity is "freeze-casting," also known as “ice-casting”.
• ice-casting also known as “ice-casting”.
• An overview can be found in "Controlling Porosity and Pore Size Distribution in Green Ceramic Bodies via Freeze Casting Method” (D. Donchev, Ph.D. thesis, Martin-Luther-Universitaet Halle-Wittenberg, 2005).
• an aqueous slurry of a gel or a sol containing particles is frozen and subsequently freeze-dried. After evaporation of the ice at low temperatures via sublimation during the freeze- drying step, the removal of the ice crystals lead to channels and pores within the ceramic bodies. The freezing rate determines the size of the ice crystals, and thus the size of the channels and pores obtained in the final product.
• Freezing droplets comprising a zeolite suspension and subsequent freeze-drying should thus lead to the desired material, e.g. spheres with a controllable porosity.
• silicalite- 1 The zeolite type used for adsorbing the gas particles (air) in the spheres was silicalite- 1. Synthesis procedures of silicalite- 1 are well known to a person skilled in the art and can be found e.g. in (Kalipcilar, H., and A. Culfaz. "Synthesis of Submicron Silicalite-1 Crystals from Clear Solutions.” Crystal Research and Technology 35.8 (2000): 933-942.)
• Production of monodispersed spherical droplets can, for example, be realized by nano- dispensing (using a PipeJet P9 setup from Biofluidix GmbH) or an induced decay of a laminar fluid jet, as described by (Sakai, Takeshi, and Norimasa Hoshino. "Production of uniform droplets by longitudinal vibration of audio frequency.” Journal of Chemical Engineering of Japan 13.4 (1980): 263-268.).
• the monodispersed spherical droplets generated by any method can be frozen, for example, directly in liquid nitrogen or during free fall in a cold gas atmosphere.
• the freezing process of a single drop is very complex and cannot be easily controlled since the freezing process is dependent on a variety of parameters, such as the thermal conductivity of a liquid or frozen fluid (such as a suspension of water, polymeric binder and zeolite), the heat transfer from the droplet to surroundings via a rotating or non-rotating droplet or convection currents within the droplet.
• a liquid or frozen fluid such as a suspension of water, polymeric binder and zeolite
• the inventors could not completely explain when shattering or formation of protrusions occurs.
• the inventors observed an increasing number of non-spherical droplets with increasing size (volume) of the droplets (increasing volume-to- surface ratio).
• the aforementioned defects such as spikes, protrusions and cracks, lead to several disadvantages during production (e.g. deficient product) and in applications (e.g. flowability) of the beaded material.
• One disadvantage observed during usage of the beaded material is in a loudspeaker device.
• the degradation and attrition of the sharp edges, spikes or protrusions can lead to formation of dust, which might be harmful to the human lung. Such a dust formation should be avoided, especially for loudspeakers in hand-held devices.
• one of the round particles is spherical or not can be determined within a confidence interval by use of photographs or more preferable by scanning electron micrographs (SEM), as shown in Fig. 8. However, in a SEM micrograph, only about 50% of the surface of particles is visible. Thus, we assume one particle to be spherical with a probability of at least 50% if the following three conditions are fulfilled:
• the SEM-image of the particle is considered to be a 2-dimensional projection, although the SEM-image contains useful information about its 3-dimensional structure and morphology.
• the first condition will therefore be given as: I) If a particle is superimposed by a circle in a manner that the particle projection completely fills the circle and the circle has the maximum radius possible, the area of the particle projection outside the circle should be less than 20% of the area of the circle.
• the Gaussian curvature of the entire surface visible in the micrograph must be positive on a length scale of l/30th of the diameter of the perfect circle described in condition 1, meaning it cannot be distinguished from a surface with an exclusively positive Gaussian curvature with an optical resolution of l/30th of the diameter of the perfect sphere described in condition 1.
• a negative Gaussian curvature refers to hyperbolic points, in which the surface is locally saddle-shaped.
• FIG. 3 A shows an exemplary one of the particles. It is obvious that the area outside the inscribed circle in FIG 3 B is much larger than 20 % of the area of the inscribed circle. The particle is thus defined as non-spherical, as the particle does not fulfil condition I).
• FIG. 4 Al shows a particle with several visible saddle surfaces caused by a protrusion which points mainly in direction of the viewer. Some saddle surfaces are marked white in Fig 4 A2. The particle is thus defined as non-spherical, as the particle does not fulfil condition II).
• Fig. 4 Bl shows a particle, which projection allows drawing circles of curvature attached to its outline; the center of these circles lie outside the particle projection.
• One of these circles of curvature is shown in Fig. 4 B2. This particle is thus defined as non-spherical.
• Fig. 4 CI shows a particle which is defined as being spherical, despite the area outside of a circle drawn by the conditions defined in III) (Fig. 4 C2), because the area outside the circle is less than 20% of the whole area of the particle projection.
• the particle is considered to be spherical, with a probability of at least 50%.
• An assemblage of particles is considered to work properly in the back volume of a loudspeaker device without generating too much dust if at least 75% of the particles are spherical as defined above.
• An assemblage of particles is considered to exhibit 25% non-spherical particles within a given confidence interval if a control sample consisting of n particles shows a certain number of non-spherical particles. Since the probability of detection of a non-spherical particle is assumed to be 50%, the probabilities p is calculated by
• n the number of particles in the control sample and z is the number of observed non-spherical particles.
• mono- disperse refers to a collection of particles that are substantially of the same size, shape and mass.
• microporous refers to pores with a diameter smaller than 2 nm.
• macroporous refers to pores with a diameter greater than 50 nm.
• zeolite silicalite- 1 powder was dispersed in 30 g water using a high shear mixer to form a suspension.
• the pH of the suspension was adjusted to 9.5 using a 4 M solution of sodium hydroxide.
• 10 g of a polymeric binder e.g. an alkaline water-based polyacrylate suspension with a solid content of 30%
• Homogenous droplets with a diameter of 0.4 mm of the suspension were produced using a PipeJet P9 (from the company Biofluidix) and directly frozen in liquid nitrogen after a falling distance of 30 cm in ambient air. After freezing, the spheres were freeze-dried under vacuum until the moisture content was below 3 %. The volume of one sphere corresponds to appr. 34 nl.
• the stable zeolite-polymer suspension produced as described in example 1 was filled in a 250 ml pressurized glass vessel and connected to the shell inlet 1 of a concentric double nozzle (FIG. 5) with an outer nozzle 2 diameter of 0.6 mm.
• the pressure was increased using a high precision pressure controller in steps of 5 mbar until a stable laminar single jet of suspension was reached (flow: approximately 24 g/min).
• the inlet 3 of the core orifice 4 with a diameter of 0.1 mm was connected to the outlet 5 of a pressurized-air device (FIG. 6) with a high precision pressure controller connected to the inlet 6.
• the air-pressure was increased until air was ejected from the inner nozzle 4 and destroyed the laminar flow of the jet of the suspension.
• the air-pressure was reduced in 5 mbar steps until no air was ejected from the nozzle anymore and the jet was laminar again.
• the loudspeaker 7 was switched on and driven via a function generator with a sinus wave of varying frequency.
• the distance between the loudspeaker membrane and the core orifice 4 was less than 30 cm, thus within the nearfield of generated pressure waves of approx. 700 Hz.
• the drops were frozen in a cylindrical cold gas container made of EPS with a height of 3 meters and a inner diameter of 60 cm that was cooled by spraying enough liquid nitrogen from the top into the container so that the temperature inside the container did not exceed -180° C.
• the drops were collected in a liquid nitrogen bath.
• the frozen hollow spheres were freeze-dried and sieved as described in example 3.
• Measurement of the electrical impedance is a well-known method for a person skilled in the art.
• the size effect of particles is shown for a cylindrical back cavity with a high length-to- diameter aspect ratio of 10: 1 together with a small loudspeaker that is commonly used in mobile devices.
• the spherical particles synthesised in example 1 and 2 with two different diameters were filled into a cylindrical back volume (0.5 ccm) with an inner diameter of 4 mm and a length of 40 mm.
• the measurement was performed using a setup e.g. as described for the program LIMP that can be found under http://www.artalabs.hr and in US20130170687A1.
• the material synthesized in example 2 and 4 were measured in a cubic backvolume (0.5 ccm).
• US4671909 As described in US4671909, the injection of air or gas into the center of a laminar liquid jet can lead to individual drops with included gas volume (bubbles).
• the object of the invention US4671909 is to use a coaxial nozzle to blow a dispersed particle film forming composition to form hollow green microspheres with uniform thin walls.
• the introduced gas volume therefore has to be sufficiently small in order to keep the void space in the back volume as low as possible and to guarantee a high loading with gas absorbing material, e.g. zeolite, respectively.
• gas absorbing material e.g. zeolite
• Example 4 describes a method for the production of spheres with an improved pore system. As shown in FIG 8, the obtained spheres are similar to the ones in FIG 7 and are also round and free of protrusions. However, as shown in FIG 9 by mercury intrusion measurements, the percentage of macropores could be increased.
• the material obtained in example 4 exhibits 22 % of its total pore volume as macropores in the range between 2 and 40 ⁇ pore radius (FIG 9 A) compared to 10 % in the material obtained in example 3 (FIG 9 B). The effect of this macroporosity on the acoustic performance of the materials is believed to be relevant, as shown in FIG. 10.
• example 2 The material of example 2 (FIG 10 A) was compared to the material with improved porosity of example 4 (FIG 10 B) by measuring the electrical impedance in a 0.5 ccm back cavi- ty in a setup as described in example 5. The resonance frequency of the improved material is shifted to a lower frequency range.
• the hollow nature of the particles can be seen in high magnification images (FIG. 11).
• the improved material showed no dust abrasion in the back cavity during filling and operation of the loudspeaker. Since the particle has an diameter of approximately 1000 ⁇ , the cavity with an diameter of approximately 500 ⁇ can be clearly seen if the optical resolution is at 1/30 of the particle diameter, e.g. at approximately 17 ⁇ .

Landscapes

• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Inorganic Chemistry (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Nanotechnology (AREA)
• Thermal Sciences (AREA)
• Health & Medical Sciences (AREA)
• Otolaryngology (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Polymers & Plastics (AREA)
• Medicinal Chemistry (AREA)
• Silicates, Zeolites, And Molecular Sieves (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Separation Of Gases By Adsorption (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Details Of Audible-Bandwidth Transducers (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=54013595

Family Applications (1)

Country Status (8)

Cited By (6)

Families Citing this family (7)

Citations (8)

Family Cites Families (50)

• 2015
  • 2015-07-07 GB GB1600709.8A patent/GB2567608B/en active Active
  • 2015-07-07 GB GB1511875.5A patent/GB2540160B/en active Active
• 2016
  • 2016-06-28 WO PCT/US2016/039911 patent/WO2017007644A1/en not_active Ceased
  • 2016-06-28 DE DE112016003091.6T patent/DE112016003091T5/de not_active Ceased
  • 2016-06-28 US US15/195,999 patent/US10349164B2/en active Active
  • 2016-06-28 AU AU2016289385A patent/AU2016289385C1/en active Active
  • 2016-06-28 JP JP2018520380A patent/JP2018531150A/ja active Pending
  • 2016-06-28 CN CN201680039806.9A patent/CN108025283B/zh active Active
  • 2016-06-28 KR KR1020187003765A patent/KR20180054564A/ko not_active Ceased

Patent Citations (8)

Also Published As

Similar Documents

Legal Events