Adjustable form for casting concrete culverts

Adjustable form for casting concrete culverts

in amount of up to 60 weight % of the resin. The resultant creep-free prepreg contains about 30-80 weight %, based on the weight of the resin, of rein...

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in amount of up to 60 weight % of the resin. The resultant creep-free prepreg contains about 30-80 weight %, based on the weight of the resin, of reinforcing mat. Method for makine ulaas fibre mats usintt controllable fibre g&s&and feeders Bailev P.E. and Rauf S. (PPG Industries. Inc.. Pittsburgh, PA, USA) ‘US Pat 4963176 (18 October 1990) At least one strand feeder traverses back and forth across the surface of a moving conveyor thereby depositing at least one strand from a supply onto the surface of the conveyor. The position of the feeder is sensed and the data the deposition rate so that a uniform mat is produced. Method of making a composite body Rasmussen G. (Plouahmann & Vinatoft, Copenhagen K, Denmark) US Pat 4963212 (16 October 1990) A number of sheets of wood with roughly parallel longitudinal grains are overlaid with a curable adhesive between the layers. The sheets are bent transversely to the grain and cured to form a shaped solid laminate which is cut parallel to the grain to form shaped strips which are positioned with curable adhesive between them and further bent in a direction perpendicular to the grain (but different to the first one) and cured to form a three dimensional furniture frame. Method for debulking precured thermoplastic composite lnminae Ayers D.J. (The Boeing Company, Seattle, WA, USA) US Pat 4963215 (16 October 1990) A number of non-tacky, partially precured thermoplastic composite layers are placed on top of a forming tool to give a bulky laminate stack that is thicker than the desired laminate thickness. A vacuum bag is placed over the stack and the tool and pressure is applied to debulk the laminate stack to approximately the &sired thickness. The bag is tensioned to remove wrinkles and then sealed whilst the pressure is maintained. Method for fabrication of refractory composite tubing Davis H.O. and Barrier J.M. (Kaiser Aerotech, San Leandro. CA. USA) US Pat 4963301(16 October 1996) ’ Continuous reinforcement fabric is rolled under tension onto a mandrel under heat and pressure. The fabric is pre-impregnated with a refractory matrix precursor or served with a thermoplastic. The precursor or serving on the rolled fabric are cured under vacuum at elevated temperature and the cured material is converted by pyrolysis to the refractory matrix whilst the fabric is on the mandrel which has a coefficient of thermal expansion 1 .l - 10 times greater than that of the refractory matrix. The fabric is impregnated with additional matrix precursor which is then converted and this is repeated until the desired matrix density is achieved. Programmably controlled fibre glass strand feeders and improved methods for making fibre mats Schaefer, W.L. (PPG Industries, Inc., Pittsburgh, PA, USA) USA Pal 4 964 891 (23 October 1990) A method for making a mat of continuous fibre strands in which at least one strand feeder traverses the width of a conveyor whilst it deposits strand onto the surface of the

Composites

Manufacturing

No.

2 1992

conveyor. The transverse motion and the deposition of the strand are controlled by separate electric motors which can be adjusted independently so that a loose mat with substantial uniform thickness and density can be deposited. Process for making gypsum plasterboard Stipek, J., Bahner, F., Hose, H., Freisinger, K. and Eidam, H. (Babcock-Bsh Aktiengesellschaft Vormals Buttner-Schilde-Haas AG, Krefeld, Germany) US Pat 4 966 739 (30 October 1990) Boards are moulded and cut from a mash containing calcium sulphate dihydrate and a fibrous material which releases setting retardant impurities on heating. These boards are autoclaved at a temperature of 115-180°C to dehydoxylate the calcium sulphate dihydrate and generate the retarder impurities. The boards are then cooled; the impurities removed by drawing or forcing an aqueous liquid through them and finally they exposed to temperature and humidity sufficient to convert the dehydroxylated calcium sulphate back to calcium sulphate dihydrate. Adjustable form for casting concrete culverts Strauch, C.R. (Hyway Concrete Pipe Company, Findlay, OH, USA) US Put 4 969 626 (13 November 1990) A form of fabricating concrete structures on a horizontal surface which has four side wall panels in two opposed pairs. These panels may be maintained in a pre-selected angular orientation and are secured to a pair of haunch forms which are then each connected to a leg form. The side wall panels are releasably hinged. Apparattw for producing fibre-reinforced thermoulastic material for the production of mouldiigs Ehnert, G. and von Paumgartten, R. (Menzoht GmbH. Kraichtal-Menziaen. Germanv) US Pat 4 9b9 971 (13 November’l990) *’ The apparatus consists of a supply duct and a melting channel for softening the fibrereinforced thermoplastic to a viscous condition. The thermoplastic from the supply duct is forced through the channel as a continuous strand by a piston and is subsequently divided into mouldable charges at a dosing station. Method of producing and using a cement-type __ binding materiel Koslowski. T.. Ludwig. U. and Froehlich. A. (Kalkwerke Rheine GmbH, Bochum, Germany) US Pat 4 971627 (20 November 1990) Flue gases are desulphurised to provide a starting product containing calcium as calcium sulphite, calcium sulphide, calcium hydroxide or calcium carbonate. The starting product is mixed with flue ash or flue dust in such proportions so that any free lime present or produced by subsequent processing is completely bound by aluminates and silicates capable of reaching with water. The mixture is heated to 700-950°C to form a multiphase product containing S-60 parts by weight Cs, 2-35 parts by weight C,,A, l-20 parts by weight C,A,Cs and 3-50 parts by weight C,S where C = CaO, s = SO,, A = Al,O, and S = SiO,. The product is ground to a Blaine fineness of 3000- 10 000 cm* g-i and is then mixed with a slag sand milled to a Blaine fineness of 25OC-5000 cm2 g-i in the proportions of 100 parts by weight to lo-50 parts by weight respectively to form a cement material.

Concrete forming system Miller, B.J. and Turner, D.W. (Foam Form Systems, Inc., McHenry, IL, USA) US Pat 4 972 646 (27 November 1990) A forming system comprised of at least one pair of wall panels with a skeletal grid between them. The ends of this grid are attached to a similar grid between panels arranged at an angle to the first pair of panels. The grids are designed to embed in the concrete that is poured between the panels. Continuous concrete mixing apparatus Zmarlicki, H. (Deborah La., Farmington, CO 06032, USA) US Pat 4 973 167 (27 November 1990) An apparatus for the continuous mixing of cement, aggregate and water comprised of a rotatable drum with loading and unloading points at the extremities of the axis of rotation. The mix is directed from one opening to the other by a series of vanes some of which direct the mix towards one opening and some of which direct it towards the other. Method for production of fibre-reinforced thermosetting resin moulding material Tamura, K., Yamamoto, S., Hashimoto, T. and Saijyo, H. (Nippon Shokubai Kagaku Kogyo Co., Ltd, Osaka, Japan) US Pat 4 973 440 (27 November 1990) Liquid thermosetting resin is supplied to at least one spreading roller which spreads it out in the form of particles and allows it to be mixed with separately spread reinforcing fibres. The resultant mixture is piled and then deaerated thus causing the reinforcing fibres to be impregnated with the resin composition. Process for producing fibre reinforced plastics linear materials Hattori, M., Komada, M., Ioka, H. and Yamamoto, Y. (Nitto Denko Corporation, Osaka, Japan) US Par 4 975 232 (4 December 1990) Reinforcing fibres are continuously moved sideways and firstly impregnated with resin before being shaped and semi-cured to produce a reinforced linear plastic with at least one lengthwise groove in it. This material is then twisted before being fully cured. Method of moulding a fibrereinforced composite steering wheel Henigue, C. (ECIA-Equipements et Composants Pour I’Industrie Automobile, Audincourt, France) US Pat 4 975 235 (4 December 1990) The wheel is comprised of a central hub and rim connected by at least one radial branch. It is manufactured by firstly filling a mould with blanks of at least one synthetic material charged with long fibres and then stamping the blanks with a punch to shape them in one operation into a lightened steering wheel. Winding apparatus for sheet-shaped moulding material Tsujimoto, Y., Kurita, M. and Aoki, M. (Takeda Chemical Industries, Ltd, Osaka, Japan) US Pal 4 976 473 (11 December 1990) An apparatus for winding a carrier film covered sheet-shaped moulding material comprised of a paste-like resin impregnated with glass fibre or the like into a roll of moulding material. The apparatus is comprised of a frame with at least one winding means on it that can support a detachable winding core tube. The sideways movement of the moulding material is restricted by side plates and the material is fed onto the core roll by a guide sheet which can be cut after the material has started to be fed onto the winding core.

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