GB514106A - Improvements in or relating to muffle furnaces - Google Patents

Abstract

514,106. Furnace atmospheres. GAS LIGHT & COKE CO., LLOYD, P., and VYSE, C. March 23, 1938, No. 8949. [Class 51 (ii)] A neutral or slightly reducing or oxidizing atmosphere gas is supplied to a muffle by means of an aerated gas burner located externally of the muffle and arranged to provide a flame to which secondary air is accessible from the surrounding atmosphere, means being provided for collecting the products of combustion and conducting them to the muffle. In the construction shown a bunsen burner 60 having means for controlling the gas and primary air supplies is vertically adjustable in the bracket 52 and burns beneath the flared lower end 59 of a tube 50 having branches 49 delivering either directly or through perforated pipes to the muffle beneath the work support 29. The tube 50 can be adjusted vertically to vary the amount of secondary air drawn in by the flame by means of cam collar 55 fixed to the tube and a cam track 57 on the bearing 51. The whole of the fittings with the exception of the burner may be covered by the muffle door which may also, have a controlled outlet for the gases. In order to prevent surges of back pressure which may develop in the muffle from affecting the burner the tube connection may include a T-piece one limb of which is open to the atmosphere. A form of muffle is described, Fig. 7, not shown, having an oil bath seal at the discharge end, into the casing of which the atmosphere gas is delivered.