Patent GB-957518-A (GB)
Title: Improvements in and relating to the fixing of tubular electric heating elements
IPC: H05B3/04
Filed: 1960-07-19
Abstract: 957,518. Jointing. A. BLECKMANN, E. DAMHOFER, and H. BLACKMANN, [trading as BLECKMANN & CO.]. July 19, 1960 [July 23, 1959; Sept. 4, 1959; Feb. 23, 1960], No. 25175/60. Headings B3Q and B3V. [Also in Divisions H2 and H5] A method of fixing tubular electric heaters in openings of container walls, flanges and the like, with the aid of fittings having passage openings for the heaters, is in that thin walled fittings of deformable but shape retaining material provided with at least one passage opening are connected with the heater ends in liquid tight fashion, the said fittings being introduced in common with the heaters into the wall opening as far as a stop formed on the fitting and then clamped in a replaceable and liquid tight manner against the container or like wall surrounding said opening by deformation of the fitting so as to change the shape of the said passage opening or openings therein, a sealing packing being interposed between said fitting and said container or like wall. In an embodiment a sleeve 2 is fitted on the end of a tubular heater 1 and one end 2a of the sleeve is radially pressed on to the heater tube. A corrugation 3 in the sleeve accommodates a gasket 4 so that when the corrugation is upset axially and radially the gasket is compressed between the sleeve and the heater tube. The assembly is introduced into an opening 5 in a housing wall 6 until the corrugation firmly engages a gasket 7 bearing on the housing wall. An apertured plate 8 is placed over the protruding end 2b of the sleeve which is flanged to secure the assembly in the housing wall. The plate 8 is formed with a break notch 9 and a slot 10 for receiving the blade of a screwdriver to break the plate along the notch to enable the heater tube and sleeve to be removed from the housing wall. Alternatively, the sleeve is first fixed in the wall and then the heater tube is inserted in the sleeve which is upset into the tube. In another embodiment a pair of heater tubes are mounted in a sleeve 11 having a pair of sleevelike extensions 12, Fig. 4. A reinforcing plate 14 and a gasket 17 are accommodated in the corrugation 13 and the protruding portion of the sleeve which is expanded to fix the assembly in the wall 6 is provided with a tab 19 with which the expanded portion of the sleeve can be pulled off. The wall gasket may be of U-shaped crosssection for engaging the edge of the wall opening and the corrugation may include a tear-off wire which when pulled separates the sleeve adjacent the corrugation. Figs. 6 and 7 show modifications of the embodiment shown in Fig. 2. In another embodiment the opening in the housing wall is elongated to accommodate a pair of heater tubes 1, Fig. 9, mounted in an elongated sleeve 55. A bead 60 is provided on the sleeve for facilitating its removal from the wall 6 by compression of the bead which disengages the expanded portion of the sleeve from the wall and enables the sleeve to pass through the wall opening. In a further embodiment, Fig. 11, a circular fitting 61 is inserted in an opening in the housing wall 6 and then flanged at 63 with a gasket 62 interposed. The fitting 61 has an opening 64 in which a heating element 1 is affixed with the aid of a fixing sleeve 2 and a gasket 64. In a still further embodiment the sleeve fitting is bowl shaped and is provided with a flange 78, Fig. 18, for engaging a gasket 79 surrounding the wall opening 5. When assembled in the opening the sleeve is corrugated with an expanding tool having two jaws 80 along the longitudinal sides of the fitting to secure the fitting to the wall. The flange 78 carries two protruding lugs 81 to which tongs or the like can be applied when it is desired to remove the fitting by squeezing the lugs together. The bowl-shaped sleeve is used in conjunction with an S-shaped sleeve 84 and gaskets 85 and 86, Fig. 2, the sleeve 84 being upset axially to firmly engage the heater tube and the rim of the opening in the bowl-shaped sleeve 82. Apparatus for carrying out the method comprises a housing 95, Fig. 25, in which expanding tongs 97 consisting of pivoted toggle levers 96 and slidable back stays 98 are mounted. The tongs are operated by a conical cam 99 displaceable by a fluid operated piston 103 in a cylinder 102. When piston 103 reaches the end of its stroke with the tongs expanded fluid pressure is supplied to a cylinder 109 to operate a piston 110 which moves the back stays 98 to compress the sleeve fitting and complete the jointing operation. The amount of deformation can be adjusted by a stop nut 113 mounted on the piston rod 111.