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US 9,167,628 B2Granted
Electric heating device for hot runner systems
AssigneeGunther Heisskanaltechnik GmbH
InventorHerbert Gunther
Life of this patent
Estimating the term…
Abstract
An electric heating unit for hot runner systems, and in particular for hot runner nozzles and/or hot runner manifolds includes at least one tubular or muff-like support and at least one heating layer fitted with heating conductor tracks. The heating layer is a fired foil or a fired thick-film paste and the muff-like support is able to be slipped onto a material feed pipe.
Claims27
A hot runner nozzle having a cylindrical material feed pipe and an electrical heating unit, the material feed pipe comprising:
- a first end and a second end;
- a wall;
- a base at the first end of the cylindrical material feed pipe;
- and
- a nozzle tip at the second end of the cylindrical material feed pipe;
- and
- the heating unit comprising:
- a tubular or muff-like support made of a sintered ceramic;
- a heating layer deposited on said ceramic support, said heating layer comprising meandering heating conductor tracks;
- and
- an outer cover layer externally covering and electrically insulating the heating conductor tracks and the tubular or muff-like support below;
- wherein
- the heating layer and the cover layer being a fired foil or a fired thick-film paste;
- wherein
- the cylindrical material feed pipe has a greater thermal expansion than the tubular or muff-like support;
- and further wherein
- in a first state before heating the tubular or muff-like su ort of the heating unit is slipped at a clearance fit with a predetermined clearance on the cylindrical material feed pipe, the clearance fit allowing the heating unit to be exchanged in the first state, the predetermined clearance being such that in a second state, which is a heated state of the heating unit, an expansion of the cylindrical material feed pipe as a result of the thermal expansion of the cylindrical material feed pipe being greater than the thermal expansion of the tubular or muff-like support achieves a direct heat transfer between the tubular or muff-like support and the cylindrical material feed pipe.
14 more elements
A hot runner nozzle having a cylindrical material feed pipe and an electrical heating unit, the material feed pipe comprising:
- a first end and a second end;
- a wall;
- a base at the first end of the cylindrical material feed pipe;
- and
- a nozzle tip at the second end of the cylindrical material feed pipe;
- and
- the heating unit comprising:
- a tubular or muff-like support made of a metal, a metal alloy, steel or a steel alloy;
- an insulating layer deposited on the tubular or muff-like support;
- a heating layer deposited on said insulating layer, said heating layer comprising meandering heating conductor tracks;
- and
- an outer cover layer externally covering and electrically insulating the heating conductor tracks and the insulating layer;
- wherein
- the cylindrical material feed pipe has a greater thermal expansion than the tubular or muff-like support;
- wherein
- the heating layer, the insulating layer, and the cover layer being a fired foil or a fired thick-film paste, and
- in a first state before heating, the tubular or muff-like support of the heating unit is slipped at a clearance fit with a predetermined clearance on the cylindrical material feed pipe, the clearance fit allowing the heating unit to be exchanged in the first state, the predetermined clearance being such that in a second state, which is a heated state of the heating unit, an expansion of the cylindrical material feed pipe as a result of the thermal expansion of the cylindrical material feed pipe being greater than the thermal expansion of the tubular or muff-like support achieves a direct heat transfer between the tubular or muff-like support and the cylindrical material feed pipe.
14 more elements
Dependencies are inferred from the claim text.