Abstract: A detection system for anaerobic micro-organisms involves the addition to a nutrient medium for the micro-organisms of an indicator species which is electrochemically reducible, soluble in the nutrient medium and consumed by the micro-organisms during growth. Two electrodes are immersed in the nutrient medium and changes in an electrical property of the nutrient medium are monitored. A preferred indicator species is riboflavin.

Abstract: A process for the production of a wall for a package including producing a preform of the wall and stretching the preform of the wall where the preform includes a layer containing a polymer and having oxygen-scavenging properties. The preform and the stretching ratios applied are chosen (i) so that the time (t.sub.I) which the permeance of the wall for oxygen would take to rise to 1/5 of the value it would have in the absence of oxygen scavenging would be at least 10 days and (ii) if the preform were stretched at that time (t.sub.I) after the preform were produced, the time (t.sub.D) which the permeance of the wall for oxygen would take to rise 1/5 of the value it would have in the absence of scavenging would be at least 1/4 of the time (t.sub.I). The time between completion of step (A) and the commencement of step (B) is at least 10 days.

Abstract: An electro-magnetic induction heater has a heating coil which defines a throat through which a metal strip (moving towards a plastics film laminating station) passes thereby to be heated to a laminating temperature. The coil turns are flexible, and are braced at spaced positions in braces which are mounted for movement towards and away from the metal strip. Each brace has an associated adjustment means. The positions of the respective braces are adjusted during heating, preferably automatically, so as to adapt the coil throat shape to the varying cross section (and/or other characteristics) of the strip to be heated, thereby to ensure uniform temperature distribution across the width of the strip. Under automatic control each adjustment means is operated in closed loop manner by associated actuating means in response to deviation from a reference level of a sensed temperature signal provided by an associated sensor positioned adjacent the emergent heated strip.

Abstract: Apparatus for resistance welding an elongate seam in a tubular article, comprises a first electrode wheel outside the article, a second electrode inside the article and a continuous electrode wire arranged to pass over the electrodes to provide surfaces of contact between the electrodes and seam material. The second electrode has a stationary block having a guide surface of like curvature to that of the outer electrode wheel so that the contact arcs of wire passing over the guide surface with the seam material is substantially equal to the contact area of wire passing over the external wheel. The use of this stationary inner electrode improves the weld of geometry and permits welding of can bodies of relatively smaller diameter without use of mercury contact bearings.

Abstract: A method is described for stretch blow-moulding thermoplastics bottles (50) from heated parisons of thermoplastics material such as polypropylene. The parisons are severed from thermoplastics sticks (51) each of which is formed of several, e.g. five, parison lengths. The sticks are severed from the leading end of a continuously extended thermplastics tube, and are individually heated in an oven to orientation temperature. After heating, the sticks are presented for severance as successive groups of associated sticks which are advanced longitudinally one parison length at a time while disposed in parallel, laterally aligned relation. The bottles are formed by repeated stretch blow-moulding operations upon the groups of parisons so produced.

Abstract: A metal can end (10) has a metal pull tab (16) attached to a score-defined detachable portion (15) of the can end by direct welding of protective polymer coatings (19,20) whose surfaces at least are derived from the same monomer and which are provided on the upper side of the can and the under side of a shank portion (18) of the pull tab. The coatings may be composite films each comprising an inner layer of a bonding resin and an outer layer of a polyolefin, polyamide or polyester. The welding may be effected by heat or preferably by ultrasonic energy.

Abstract: A laminated metal sheet having adhered to one of its major surfaces a composite co-extruded polyolefin-containing film (B) comprising a plurality of layers in the following order:(B1) an inner layer of a bonding resin which is an acid modified polyolefin resin containing carboxyl or anhydride groups,(B2) a layer of a polyolefin,(B3) a further layer of a bonding resin which is as defined for layer (B1), and(B4) a layer of a polyamide.The laminates of the invention are useful for forming into containers or various components therefor.

Abstract: A method of making a laminated structure in which a polyethylene element is bonded directly to a metal substrate by the application of heat and pressure is characterised by the selection of the polyethylene, for the purpose of obtaining good adhesion, to be a linear low density polyethylene having a density from 0.91 to 0.94 g/ml.sup.-1 and a melt flow index in the range 0.2 to 2.0 g/10 min, produced by low pressure co-polymerisation of ethylene and but-1-ene. The polyethylene may be pre-treated, e.g. by corona discharge, glow discharge or flame treatment to further improve the adhesion. The polyethylene element may be a film applied to one or both sides of the metal substrate which may be a sheet or foil.

Abstract: A plastics collar for retaining a plug lid 45 in a ring 44 double seamed to can body 1, has a peripheral skirt 38 portion having on its interior surface a snap fit bead 41 for entering under the double seam 3; a planar annulus 37 extending radially inwards from the top of the skirt over the seam 3 and at least part of the ring 44 and lid 45; and an annular rib 43 extending down from the planar annulus to hold the lid in the ring. The collar may be provided with a jacking screw 39 to assist removal from interlock with the double seam 3 and progressive removal is facilitated by a radial slit or line of weakness at which the collar first parts from the can.

Abstract: Solid foodstuffs, such as chips, are sterilized for subsequent aseptic packaging and non-refrigerated storage in a hot fluid medium within a closed reaction vessel, under an applied pressure such as to elevate the boiling point of water in the product to at least the minimum lethal temperature for the most harmful micro-organisms and spores that may be present.

Abstract: A tray-type food container for food which is to be heated or re-heated in the container comprises both a flat outer lid heat-sealed to a horizontal flange on the tray and a perforated inner lid of substantially rigid and preferably transparent material which is supported on a step in the wall of the tray and is shaped so as to extend above the level of the step and to provide finger holes whereby it may be grasped and removed after the outer lid has been removed. The inner lid may support the outer lid flush with the flange. The flange may have a peripheral groove to form a guide for a knife for removal of the outer lid. The flange may also carry heating instructions in a machine readable code. A vending machine comprising a microwave oven may be provided with means for selecting a container from a number of stacks and with means for reading the coded heating instructions and regulating the energy supply to the microwave oven accordingly.

Abstract: A metal can end with a one-piece tear-open closure of a polymeric material (e.g. a polyolefin or polyamide) moulded thereon so as to fill an aperture therein and to form a rim surrounding the aperture on the underside and a pull tab lying against the upper side of the can end, wherein the underside of the can end has a coating of a polymeric material bonded to the polymeric material of the rim and the upper side has a coating whose outer surface is of a different polymeric material which will not bond to the polymeric material of the closure, the materials of the coatings being chosen to be capable of being laminated simultaneously to the metal of the can end, e.g. by the use of bonding resins such as an acid-modified polyolefin resin.

Abstract: In a high speed apparatus having a rotating turntable, an infeed device has a rotatable turret from which radiate a plurality of can holders which act to transfer cans from an infeed conveyor along an encircling guide rail to the rotating table. A cam element enclosed in the turret may cyclically retract each holder to cause the can to follow the periphery of the rotating turntable.

Abstract: A machine for filling packaging containers with a flowable product comprises a control valve in the form of a plug valve having a body defining a bore forming a frusto-conical valve seat, a plug having a complimentary frusto-conical surface, and a valve chamber for pressurized fluid formed at the wider end of the plug. The chamber communicates with the bore. The plug is axially displaceable between a first position, in which the frusto-conical surface seals against the valve seat and in which it is rotatable to control flow through the valve, and a second position, in which it is withdrawn into the chamber to provide clearance between the mating surfaces of the plug and the seat but retaining clearance between its wider end and the opposite surface of the chamber so that all surfaces of the plug are exposed for cleaning and sterilization.

Abstract: An apparatus for flanging tubular articles of a thermoplastic polymer which has been drawn and heat-set to an elevated temperature comprises a heating die (20) shaped to receive an end of one of the tubular articles (10) and to restrain it from shrinkage, transfer means such as a star wheel (24) to transfer the article (10) from the heating die (20) to a forming die (22) shaped to form an outward flange (12) on said end. Heater coils (33,40) are provided to maintain the dies at the required temperatures; namely the heating die (20) at a softening temperature above the glass transition temperature of the polymer but below the elevated temperature to which it has been heat-set and the forming die (22) at a forming temperature below the softening temperature.

Abstract: A method of removing a layer of cobalt from an underlying nickel surface of an article comprises the steps of immersing at least part of the article in an aqueous solution of a caustic alkali having a pH value not less than 12.5 and preferably not less than 14, and applying an electrical potential difference between the article and a counter electrode which acts as a cathode to strip the cobalt from the article leaving the nickel passive. The method is particularly suitable for removing a defective cobalt layer from a data storage disc so that the disc can be recoated.

Abstract: A method of making a metal can end with a tear-open plastics closure, for a can intended to be resistant to leakage when subject to internal pressures, such as arise from carbonation of a beverage or thermal processing, wherein the undersurface of the can end is provided with a plastics coating, and the can end is pierced to form an aperture with a peripheral downturned flange at an angle of 70.degree. to 110.degree. to the plane of the can end and having a flat end. A one-piece ring pull closure is injection-moulded onto the can end from a plastics material resistant to softening at up to at least 65.degree. C., without additional heating of the metal, so as to fill the aperture, bond with the coating, and enclose the flange, with a residual thickness below the flange of 0.125 to 0.5 mm. The thickness of the plastics material of the closure is such that it can be sheared against the flange when the ring pull is pulled manually.