Abstract: A sampling device samples gas from a gas stream flowing through a tube to means utilizing the gas to detect the presence or otherwise of particulate contaminants. The device ensures that the sampled flow has at least as many particulate contaminants/unit volume as the main flow. The device divides the flow into two parallel flows and then decelerates one flow before providing the sampled flow. The other flow passes to the utilizing means. The device is particularly useful in the sterile packaging of product to detect microorganisms and other culturable contamination.

Abstract: A gas sampling assembly takes a sample of a gas and passes the gas through a monitoring unit. A material within the unit removes particulates from the gas and a port is provided for feeding into the unit a material for indicating the presence of particulates. A transparent portion of the unit allows the indication to be viewed. The unit can be used in sterile packaging apparatus.

Abstract: A method of producing a porous film comprises subjecting a fibrous material comprised of fibers of a film forming material to conditions of heat and pressure to covert the fibrous material to a porous film. The method allows the production of film material having substantially uniform pore sizes. For example, the pore size distribution of the film may be such as to have a ratio of maximum pore size:mean flow pore of less than 1.2, e.g., less than 1.1.

Abstract: A method of coating porous webs wherein porous materials having a range of pore sizes are given desired characteristics by selective depostion in the large pores of particulate treatment agents. Thus some characteristics are achievable by control variation of pore size distribution (e.g. sample, uniformity, liquid filtration properties) while others depend on specific attributes of the treatment agents (e.g. response to calendaring, catalysis, security marking adhesion properties).

Abstract: A material, which may have a highly open structure such that it has negligible barrier properties, is treated with expandable particles. These are then caused to expand within the material, reducing its openness and improving its barrier properties. The product may be a porous material. The pores may be modified by an agent applied together with the particles or after the expansion. The particles may be thermoplastic microspheres containing gas. The material may be a network material, with a fiber matrix with many voids.

Abstract: A method of treating a porous material comprising establishing a pressure differential across the material and treating the higher pressure side with a suspension dispersion or aerosol of droplets of a liquid. The droplets enter at least some of the pores, with the treatment conditions being such that the aerodynamic forces within the pores exceed the surface tension forces maintaining the integrity of the droplets. The droplets thus spread to provide a surface coating within the pores.

Abstract: A nebulizer for liquids, particulate materials or liquids/solids suspensions, comprising, within a vessel (10) containing a reservoir (11), an upright duct (13) with a plurality of circumferentially spaced outlet apertures (20), enclosing a coaxial air line (14) feeding a plurality of jets (16) duly aligned with outlet apertures (20) in the upright duct (13) so that an annular column of material is drawn from reservoir (11) to be dispersed by entrainment in the air streams from the jets (16). Larger droplets may return to the reservoir (11) while the smaller fraction issues from the vessel through an outlet (12). The relatively large outlet apertures (20) and the large cross-sectional area of the column of the material prevent blockage at the nebulizer head.

Abstract: A porous material, e.g. a paper, has pores with a range of sizes. A pore modifying agent comprising particles of a narrow size range is selectively incorporated within the larger pores to provide zones of high surface area. These greatly reduce the penetrability of the material, e.g. by mirco-organisms, while having relatively little effect on its air-permeability. The modifying agent may be incorporated by creating a pressure difference across the material, and treating it with a dispersion, e.g. an aerosol, of the modifying agent, under conditions of low inertia, and incorporating only a small amount of the agent, e.g. not more than 1% w/w.