Patent GB-334768-A (GB)
Title: Method of and apparatus for making laminated glass
IPC: C03C27/12
Filed: 1929-10-25
Abstract: 334,768. Kolb, L. J., (Assignee of Worrall, A. G.). Oct. 30, 1928, [Convention date]. Compound transparent sheets.-In apparatus for making laminated safety glass, the glass assembly is placed within an open-ended rubber bag and is surrounded by strips or templets which serve to protect the edges of the assembly during the pressing operations, the bag being then clamped in an airtight manner at its open end, exhausted of air, vapour, moisture &c. by means of a pump, and placed on the upper surface of a supporting table adapted to be placed within a chamber for heat and pressure treatment. The bag support comprises a surface 23b and side members 23d, both being perforated to allow access of the heating fluid to the lower part of the bag. The bag 25 is composed of two rubber sheets strengthened on the outer sides by thin fabric 25<c> and partially covered on the inner side by canvas, the sheets being cemented together at three edges. The glass assembly 28 to be placed within the bag is surrounded by templet strips 29 preferably of slightly greater height than the glass. The templets may be of lead or other flexible metal. For placing the assembly in the bag, one end of a strip of canvas 25a is placed over a metal plate 23a, the glass assembly with the templets is placed thereon, and the canvas folded over to the dotted position, Fig. 4. The plate is then inserted with its load into the bag and then withdrawn, leaving the glass assembly with the canvas enclosure in position. In some cases a number of assemblies of different shapes, each with an enclosing templet, may be arranged within the bag. In another form, Fig. 6, particularly for making lenses or goggles, the templet may consist of a sheet of metal 29<a> having apertures to accommodate the glass assemblies. After inserting the glass, the open end of the rubber bag is clamped between plates 24a, 24<c>, connected to a suction pipe to withdraw air &c. from the bag, and then a plug 30 is inserted to maintain the vacuum within the bag. A number of supporting tables, each with a superposed bag, may be mounted in the pot 2 so that the side walls of the bag fit closely against the pot but alternate spaces are left at the ends of the bags to allow circulation of fluid, as shown in Fig. 8. The pot is then closed and fluid is circulated from a steam-heated coil 14 by means of a pump 8. The system may be initially charged by means of a pump 6. After circulating water at a temperature of 250 F. for about  hour, the pressure is raised either by injecting further water by the pump C or preferably by means of compressed air admitted from a cylinder 9 through a motor valve 11. Steam is then shut off from the heater 15 by a valve 16<a> and cold water admitted by a pipe 26 and motor valve 27, this water being allowed to overflow through motor valve 23 and pipe 22. In this way the temperature of the circulating water is reduced to 100 F., whereupon valves 11, 16<a>, and 26<a> are closed, the pressure in the pot is released by valve 3<a>, the pot drained by a pipe 2<a>, and the enclosures removed. Steam is admitted to the heater 15 through the valve 16<a>, and motor valve 17, and condensed water escapes through a motor valve 19. The motor valves are operated from a compressed air cylinder 41, the air pipes 38, 43 having valves 39, 45, respectively, which are interconnected by a link 52 so that a single control handle 50 may be employed to actuate, all the valves in the required sequence.