Ceramic heating resistor, electrical heating element, and device for heating a fluid

An electrical heating element for heating a fluid, comprising at least one tubular element through which a fluid flows or can flow, and a ceramic heating resistor disposed in the tubular element, the heating resistor being produced by sintering a green body, comprising at least one ceramic raw material, and comprising an electrically insulating component and an electrically conducting component, and the electrically insulating component forming a matrix in which the electrically conducting component is accommodated, characterized in that the heating resistor comprises an arrangement of two open helicoid bodies having respective central screw axes, the screw axes of the helicoid bodies being collinear with one another and the helicoid bodies being helically wound inside one another in a contactless manner, the central screw axes of the helicoid bodies being oriented substantially parallel to the central axis of the tubular element, the helicoid bodies being connected to one another in an electrically conducting manner in the region of one end of the helicoid arrangement and designed as separate connecting electrodes at an opposing further end of the helicoid arrangement, an electrically insulating element being disposed in at least one central cavity formed by the open helicoid bodies along the screw axes of the open helicoid bodies, the electrically insulating element having a tubular, rod-shaped or sectionally tubular and rod-shaped design, and the tubular element having an inner surface with a shape and size when viewed in transverse cross-section perpendicular to the central axis of the tubular element that is only insignificantly larger than a maximum outer surface of the heating resistor when viewed in transverse cross-section perpendicular to the central screw axes of the helicoid bodies, so as to enable insertion of the heating resistor into the tubular element, and maximize fluid flow through a helical path defined by the helicoid bodies body of the heating resistor, and is such that thermal expansion of the heating resistor during operation does not result in direct contact between the heating resistor and the tubular element.