Abstract: The present invention relates to a method of purification of compound of formula (I) which comprises the step of crystallization of compound of formula (I) from a composition comprising the compound of formula (I) and the compound of formula (II) and a specific solvent system containing ethanol, 1-propanol, 2-propanol, 2-methyl-1-propanol, 1-butanol or 2-butanol.

Abstract: The present invention relates to a method of purification of compound of formula (I) which comprises the step of crystallization of compound of formula (I) from a composition comprising the compound of formula (I) and the compound of formula (II) and a specific solvent system containing ethanol, 1-propanol, 2-propanol, 2-methyl-1-propanol, 1-butanol or 2-butanol.

Abstract: This disclosure relates to a method for producing a heating rod for a vehicle heating apparatus, said method comprising the following steps: arranging at least one PTC element and at least one contact element in a tube, which is formed from sheet metal and is open along a longitudinal side; welding portions of the sheet metal that bear against one another by means of a weld seam running in the longitudinal direction of the tube. This disclosure also relates to such a heating rod.

Abstract: The invention relates to a electric heating device for heating fluids, comprising at least one heating resistor, a screw, which defines a helical flow channel, and a tube housing, which surrounds the screw. In accordance with this disclosure, the screw has a core in which the at least one heating resistor is arranged.

Abstract: The invention relates to a heating rod comprising a tube housing, at least one ceramic heating element, which is arranged in the tube housing, a first contact plate, which in the tube housing bears against the heating element or the heating elements, and an insulating frame, which surrounds the longitudinal edges of the first contact plate. In accordance with this disclosure, a second contact plate is provided, which carries a second insulating frame, wherein the at least one heating element is arranged between the two contact plates and the two frames are plugged into one another.

Abstract: The invention relates to an electric heating device for heating fluids, comprising at least one heating rod, which has at least one heating element, a housing, which encloses the heating rod and has an inlet opening and an outlet opening, wherein the inlet opening and the outlet opening are interconnected by a winding flow channel. According to the invention, the flow channel forms a helix that has a longitudinal axis, wherein the heating rod is disposed next to the longitudinal axis of the helix and extends through a helically winding wall of the flow channel at a plurality of points.

Abstract: The invention relates to an electric heating device for heating fluids, comprising at least one heating rod, which has at least one heating element, a housing, which encloses the heating rod and has an inlet opening and an outlet opening, wherein the inlet opening and the outlet opening are interconnected by a winding flow channel. According to the invention, the flow channel forms a helix that has a longitudinal axis, wherein the heating rod is disposed next to the longitudinal axis of the helix and extends through a helically winding wall of the flow channel at a plurality of points.

Abstract: This disclosure relates to a method for producing a heating rod for a vehicle heating apparatus, said method comprising the following steps: arranging at least one PTC element and at least one contact element in a tube, which is formed from sheet metal and is open along a longitudinal side; welding portions of the sheet metal that bear against one another by means of a weld seam running in the longitudinal direction of the tube. This disclosure also relates to such a heating rod.

Abstract: The invention relates to a electric heating device for heating fluids, comprising at least one heating resistor, a screw, which defines a helical flow channel, and a tube housing, which surrounds the screw. In accordance with this disclosure, the screw has a core in which the at least one heating resistor is arranged.

Abstract: The invention relates to a heating rod comprising a tube housing, at least one ceramic heating element, which is arranged in the tube housing, a first contact plate, which in the tube housing bears against the heating element or the heating elements, and an insulating frame, which surrounds the longitudinal edges of the first contact plate. In accordance with this disclosure, a second contact plate is provided, which carries a second insulating frame, wherein the at least one heating element is arranged between the two contact plates and the two frames are plugged into one another.