a certain fixation of the position for the coil section 12 in this case as well the lower end edge of the insulating plate 10 may be provided with a notch not shown the notch is used as a deflecting edge for the coil section 12 in this embodiment as is shown by the example according to fig1 through 20 b it is also possible to establish an insulating distance from the bottom 3 by inserting a spacer ring 40 made of an insulating material e g ceramic on which the lower edge of the insulating plate 10 is seated the cavity of the tubular body 2 between the bottom 3 and the closing disk 5 is filled with an insulating material granulated insulating material 13 which may consist of quartz sand or a metal oxide especially magnesium oxide a granular product consisting of heat resistant plastic may also be used for this purpose it shall be pointed out here that the drawings show the cartridge heater 1 in the noncompressed state in case of relatively small overall lengths of the tubular body 2 the two heating coils 8 and 9 are sufficiently guided within the tubular body 2 by the insulating plate 10 and the two terminal screws 7 which are rigidly connected to the upper ends of the heating coils 8 and 9 and are protected against bending out radially and thus against touching the wall of the tubular body if the cartridge heater has a greater overall length it is useful to secure the heating coils 8 and 9 by holding clamps 14 arranged distributed over the length these holding clamps 14 consist of u shaped flat bodies made of insulating material and are provided with u shaped recesses 15 in which the heating.