Patent GB-190610852-A (GB)
Title: Improvements in and relating to Muffle Furnaces
Inventor: FORSBACH OTTO
Filed: 1906-05-09
Granted: 1906-09-20
Abstract: 10,852. Forsbach, O. May 9. Regenerative muffle furnaces.-Relates to furnaces for enamelling, distilling zinc, and other purposes. Pre-heated air for combustion, before its admixture with gas generated in the contiguous producer furnace, traverses passages arranged at the side of or enclosing the furnace flues, and is led thence into the combustion chamber through a passage beneath the latter, the air flowing in a contrary direction to the gases. In some cases, an arrangement of pipes, through which the air passes on its way to the passages surrounding the furnace flues and along the outside of which the waste gases pass on their way to the outlet, is provided at the sides of and parallel to the muffle. In the arrangement shown in Figs. 1 and 3, gas generated on the grate 1 is led through a passage 2 into a combustion chamber consisting of passages 3 arranged side by side, where the mixing of hot air and gas takes place. The burning gases pass through passages 5 into the furnace flues 6 which completely surround the muffle. These furnace flues are alternately connected above and at the side of the muffle, and thus the gases are compelled by tongues 7, 8 to take a zigzag path on the surface of the muffle. The gases on reaching the back or grate end of the furnace pass through passages 9, 10, 11 into horizontal ducts 12, along the furnace, and finally by way of vertical passages return along ducts 14 arranged parallel to and below ducts 12. They then descend by passages 15 into the outlet 18, iu which a water receptacle 17 is placed. Air for combustion, entering the rear end of the furnace, traverses the length thereof through the ducts 19, and by short vertical passages enters into and returns along ducts 21. It is then led through passages 22 to passages 23 arranged at the sides of the vertical parts of the furnace flues 6. Finally, it is taken down by passages at the front end of the furnace and brought into horizontal passages 26, whence it is discharged to mix with, and support the combustion of, the gas through orifices 27 and openings in the base of the combustion chamber. Air is admitted to the underside of grate 1 through passages 29, 30. In a modification, the passages 23 completely enclose the muffle arch as well as the side flues of the furnace. Tongues built in passages 23 cause the air to take a zigzag path over the outer surfaces of the muffle arch. A further modification, Figs. 9, 10, and 11, provides for cases in which the height of the furnace will not allow of sufficient room for the passages 19, 21 or 12, 14. At the sides of the heating-passages 23, tubular passages 33 are arranged parallel to the muffle. Air enters the passages 33 at the front of the furnace and is led by angular passages 34 at the back of the furnace into passages 23. Tongues 36, 37 hold the pipes 33, which are built into the furnace flues 35. The vertical tongues 36 merely support the passages 33, whereas the horizontal tongues 37 divide the passages 35 into upper and lower chambers. These latter communicate by openings 41 formed in tongues 37 at the front end of the furnace. Hot gases, after passing through the rearmost chamber of the flue 6, pass laterally into passages 9, 38 and thence into the upperchambers of the flues 35. The gases are drawn above the tongues 37, through the openings 41, and are returned by way of the lower chambers of the passages 35 to the rear end of the furnace. They are then led to the outlet by the passage 40.