Patent GB-638175-A (GB)
Title: Improvements in or relating to lehrs for glassware
IPC: C03B25/06
Filed: 1947-07-14
Abstract: 638,175. Glassware leers. HARTFORD-EMPIRE CO. July 14, 1947, No. 18734. Convention date, Nov. 5, 1941. [Class 51 (ii)] In a muffle-heated glassware leer, products of combustion are caused to pass rearwardly from a combustion chamber located below the entrance or preheating section and then upwardly into a passage which extends forwardly above the combustion chamber and directly beneath the floor of the tunnel. In the leer shown, the ware is transported on an openwork conveyer 22 through a tunnel 21 divided into a preheating zone extending from the front of the leer to the line 28, Fig. 5, a firing zone extending from the line 28 to the line 29, a rapid cooling zone extending from the line 29 to the line 30, an annealing and slow cooling zone extending from the line 30 to the line 31, Fig. 9, and a final cooling zone extending to the rear end of the leer. The front portion of the preheating zone is heated by a burner 35, Fig. 1, which discharges into a transverse combustion chamber 34, the combustion products passing from the opposite end of this chamber into a second transverse chamber 38 and thence upwardly through longitudinally-spaced ports 43 - 45 into a longitudinal passage 46 defined by the upper wall of the chambers and a corrugated metallic wall 47 forming the floor of the tunnel. This passage communicates at its front end with vertical flues 49 leading to exhaust stacks 50, and at its rear end with an aligned longitudinal passage 51 supplied with combustion products from a chamber 52 communicating through a diffusion chamber 64 with a combustion chamber 58 fired by a burner 61. Air supplied through pipes 67 may be admitted to the chamber 52 to reduce the temperature of the gases. Communication between the passages 46 and 51 is controlled by a damper 54 which may be swung from 'an open horizontal position to the position shown in which slight leakage of gas is allowed from the passage 51 to the passage 46 but the greater part of the gases from the passage 51 escape through lateral and vertical flues, 55, 56 to exhaust stacks 57. By adjustment of the damper, the amount of heat supplied to the forward end of the preheating zone may be increased or decreased as desired.. Gases from the chamber 58 also pass rearwardly into a heating chamber 69 closed at its rear end by a partition 71 and containing a pair of air-heating coils 78, Fig. 6, supplied through pipes 80 and connected to pipes 81 which extend longitudinally through the partitions 71 and a chamber 73, Fig. 8, below the annealing zone. These pipes are closed at their rear ends and are formed with nozzles 82 through which jets of heated air 83 are discharged into lateral passages 84, Figs. 8 and 16, which direct the air over pipes 72 through which are gases from the chamber 69 pass rearwardly to exhaust stacks 77, Fig. 9. The heated air then flows under baffles 85 and upwardly through passages 86 into the leer tunnel. The firing zone is heated at the top by a burner 96, Fig. 5, discharging into a combustion chamber 93 communicating with a forwardly-extending passage 102 ' defined by the bottom wall of the chamber and a corrugated metal wall 103 forming the roof of the tunnel. The gases flow through this passage into a vertically-extending heating chamber 105 containing air heaters 106 supplied through pipes 107 embedded on the leer structure. Air from these heaters passes into pipes 110 which extend longitudinally in the preheating zone and are formed with nozzles 111 through which jets of heated air are discharged against a central baffle 113, Fig. 17, to create a transverse circulation of the tunnel atmosphere as indicated by the arrows. The gases from the chamber 105 escape through exhaust stacks 118. The preheating zone of the tunnel is provided with damper-controlled outlets 119 and 121, Figs. 1 and 3. The rapid cooling zone is provided with cooling air pipes 123, Fig. 5, formed with nozzles 127 through which jets of air are discharged towards the middle of the upper part of the tunnel, the air being directed downwardly by central baffles to create a transverse circulation of the atmosphere. The pipes 123 are supplied through pipes 124, Figs. 7 and 16, extending longitudinally in the annealing zone. The cooling apparatus in the final cooling zone comprises longitudinally-extending pipes 129, Figs. 9 and 10, formed with nozzles through which jets of air are discharged against the inclined walls 130 of deflectors 131. The deflectors may be arranged to induce a forward or rearward drift of the tunnel atmosphere. The air supply apparatus comprises a blower 132, Fig. 3, and a blower 133, Fig. 10, the former supplying combustion air to the burners 35, 61 and 96 and pressure air to draught inducers in the exhaust stacks 50, 57, 77 and 118, and the latter supplying the various air heaters and airdischarge pipes.