GB331594A - Improvements in methods of and apparatus for manufacturing rubberized fabric or the like - Google Patents

Abstract

331,594. Firestone Tyre & Rubber Co., Ltd., (formerly Firestone Tyre & Rubber Co. (1922), Ltd.), (Firestone Tire & Rubber Co.). Jan. 10, 1929. Resistances, measuring; wire resistances, threaded and enclosed.-In the manufacture of rubberized fabric by passing the fabric through a bath of rubber dissolved in benzol and drying in a chamber containing an inert gas such as carbon dioxide or producer gas, the proportion of producer gas to benzol is determined by submitting streams of the producer gas and of the gaseous content of the chamber simultaneously to a device for comparing their thermal conductivities. As shown in Fig. 1, producer gas is led into the chamber 1 from a pipe 12 in such quantity as to form a non-explosive mixture with the benzol vapour, the gaseous mixture passing out through a pipe 13 for recovery of the benzol. Producer, gas and chamber gas respectively are passed through branch pipes 14, 15 and closed chambers 19, 21 respectively, passing out through pipes 26 and discharging below the surface of water in a vessel 27, the level being maintained constant by means of a supply pipe 30 and overflow pipe 31. Before passing to the chambers 19, 21, the gases are passed through filters 16 and narrow orifice plates 17 so that the gases are freed from foreign substances and given a constant velocity with low pressure. The chambers 19, 21 contain resistances 25 wound through holes and across an aperture 24, Fig. 3, in a plate 23 of mica which is clamped between the halves 22, Fig. 2, of the chambers 19, 21 so that the gas passes across the resistance wire in its passage through the chamber. The chambers 19, 21 are surrounded by heating coils 36 in order to maintain their temperature constant. The resistances 25 are connected to form two arms of a Wheatstone bridge adjusted so as to be balanced when the proportion of producer gas to benzol is correct. Change in this proportion causes change in the thermal conductivity of the mixture, thus causing a change in the value of the corresponding resistance 25, and causing an indication of the galvanometer 35.