GB748760A - Improvements relating to nets, especially fishing nets, and methods and machines forproducing and treating same - Google Patents

Abstract

A net, especially a fishing net, made with knotted meshes from thermoplastic synthetic resin twine, has the knots heat-set to <PICT:0748760/IV(a)/1> <PICT:0748760/IV(a)/2> inhibit subsequent slippage. Slippage of the knots prior to the heat treatment may be avoided by treating the twine, before formation into the net, with a temporary binding agent (see Group IV (c)) which is washed out during the heat treatment or at a later stage. The twine may be formed from continuous filaments or staple fibre; the thermoplastic material may be "Orlon," "Terylene," "Saran," "Vinyon," "Dynel," "Acrilan" (Registered Trade Marks), or nylon, or a mixture of two or more of these. As shown, a net A is drawn in loose form from a container 5, past a beater 3 which loosens any tangles in the net, and around tensioning rods 10, 11, 12, whereby the net assumes a ribbon or rope-like form. The net passes over pulleys 13, 14 and around a treble pulley 15 and double pulley 16, at least one of which has sections of increasing diameter, whereby the net is increasingly tensioned. The net then passes in successive loops around rollers 17, 18 in a tank 1 of boiling water; at least one of rollers 17, 18 increases in diameter towards its output end, to tension the net further, and the rollers are set at an angle to each other, to effect movement of the net from one end to the other. The net is cooled by passing around pulleys 20, 21, similar to pulleys 15, 16, in a tank 2 of running cold water, whence the net passes to a laying device 4 which lays the net in superposed layers in a receptacle 6. Each portion of the net stays in the hot water for 75 seconds, though a period of 30 seconds for 420 denier nylon is stated to be satisfactory. The net is subsequently dried while free from tension; alternatively it may be dried while still under tension. Boiling water is preferred to steam or dry heat as the heat-setting medium. When the net has not been pre-shrunk by dyeing or other pre-treatment, some shrinkage takes place in the machine, and the net is formed with a mesh size calculated to give the desired size after treatment.ALSO:<PICT:0748760/IV(c)/1> <PICT:0748760/IV(c)/2> A net made with knotted meshes from thermoplastic synthetic resin twine has the knots heat-set, to inhibit subsequent slippage, by being passed while tensioned through hot water. As shown, a net A is drawn in loose form from a container 5, past a beater 3 which loosens any tangles in the net, and around tensioning rods 10, 11, 12, whereby the net assumes a ribbon or rope-like form. The net passes over pulleys 13, 14 and around a treble pulley 15 and a double pulley 16, at least one of which has sections of increasing diameter, whereby the net is increasingly tensioned. The net then passes in successive loops around rollers 17, 18 in a tank 1 of boiling water; at least one of rollers 17, 18 increases in diameter towards its output end, to tension the net further, and the rollers are set at an angle to each other, to effect movement of the net from one end to the other. The net is cooled by passing around pulleys 20, 21, similar to pulleys 15, 16, in a tank 2 of running cold water, whence the net passes to a laying device 4 which lays the net in superposed layers in a receptacle 6. Each portion of the net stays in the hot water for 75 seconds, though a period of 30 seconds for 420 denier nylon is stated to be satisfactory. The twine of the net may be formed from continuous filaments or staple fibre; the thermoplastic material may be "Orlon," "Terylene," "Saran," "Vinyon," "Dynel," "Acrilan" (Registered Trade Marks), or nylon, or a mixture of two or more of these. Slippage of the knots prior to the heat-treatment may be avoided by treating the twine, before formation into the net, with a temporary binding agent which is washed out during the heat-treatment or at a later stage; binding agents specified are (i) a solution made up of 10 gallons water, 2 lbs. soap and 10 lbs. "Syton" (Registered Trade Mark), (ii) a rosin dip made up of 1.5 lbs. rosin soap, 3 ozs. powdered rosin and 3 gallons water.