Patent GB-547916-A (GB)
Title: Improvements in or relating to apparatus for flame hardening the internal surfaces of tubular metal articles
IPC: C21D9/14
Filed: 1941-03-27
Abstract: 547,916. Hardening hollow articles; burners. SHORTER PROCESS CO., Ltd. (Linde Air Products Co.). March 27, 1941, No. 4148. [Class 72] [Also in Group XI] In apparatus for surface hardening the inner surface portions of tubular articles, a flame heating and quenching device is provided with flame and quenching fluid outlets disposed about its periphery in alternate longitudinal relation. The periphery of the device is provided with a plurality of spaced wings, at least one longitudinal row of flame outlets being located in each wing, and the quenching outlets in valleys between each adjacent wings. When each wing carries a plurality of longitudinal rows, the tips of a central row extend outwardly a greater distance than the tips of rows on either side so as to conform to the curvature of the portions of the article being treated. For hardening the inner surface of a tapered female pipe coupling P, the heating and quenching device D is provided with three longitudinal wings W which taper outwardly from front to rear as do the threads 10 of the coupling P and each wing W is provided with three rows of heating tips T and quenching pipes 12, each with two rows of slo'ts 13 arranged in the valleys between the wings W. The device is also provided with three tip blocks K carrying heating tips T' which direct heating flames against the shoulder 11 of the coupling P. The tips T, T' are supplied with a mixture of gases formed in three blowpipes B which with the device D and other parts of the apparatus are supported on a carriage C slidably mounted on a frame F which may form part of a lathe. The gases are fed to the blowpipes B by hoses 14, 15 provided with valves 16 operated by a common handle 17 and the supply is controlled by valves 24, 25 ; the combustible mixture passing from the pipe B through tubes 26 provided with cooling jackets 27 connected by pipes 32 to a header 30 from which pass also pipes 31 leading to the wings W. Cooling medium is also passed by pipe 33 to the pipe B and leaves by pipes 34, being discharged into a sump 35.. For quenching, a suitable medium, such as water, is passed from hoses 39 through a valve 40 and hose 41 into a header 42 which feeds three quenching tubes 12. The tips T and device D are provided with a central chamber 48, Fig. 5, closed by a plug 49 fed with water through the header 36 and are also provided with two passages 56, Fig. 6, for the outer row of tips T and a central passage 55 for the central row of tips T which are screwed into apertures 54 in these passages, the passages 54 being fed with gas by tubes 57 branching off the supply pipe for the passage 54 fed with gas from the pipe 26. A branch pipe 60 from the lower passage 54 feeds gas to the device K on which the tips T<SP>1</SP> are mounted. The head is provided with four cooling passages 65 two of which are connected to bosses 52 to which are connected the supply tubes 31 and the four passages connected by a passage 66, radial passage 67 leading into the chamber 48. From the front of each wing the cooling liquid passes into this chamber whence it passes by pipe 36 into the sump 35. To prevent the overheating of the blocks K, cooling medium is passed from one of the passages 65 into a passage 72, Fig. 5, and thence through an outlet tube into one of the passages 67.