Preheating screw
AssigneeKlockner-Humboldt-Deutz Aktiengesellschaft
InventorsHeinz Caspelherr, Ulrich Huwel
Life of this patent
Estimating the term…
Abstract
A preheating screw for the simultaneous mixing and heating of fine-grained or paste-like substances, in which intensive heat transfer takes place during transport of the substance by use of a rotating hollow screw that is filled with a heat-transfer medium, preferably a fluid, heat being transfered from the heat-transfer medium to the product by way of the heated hollow screw. An electrical heating device is installed in a hollow screw shaft, and is supplied with electrical energy via sliding contacts positioned on the outside of the screw shaft.
Claims7
A preheating screw for the simultaneous mixing and heating of fine-grained or paste-like substances, comprising:
- a screw trough,
- a hollow screw rotatably mounted in said screw trough including a hollow screw shaft having a shell and a hollow helical flight secured to said shell, said screw shaft and said helical flight having cavities filled with a heat-transfer fluid,
- an electrical heating device (15) inside said hollow screw shaft (11),
- means supplying electrical energy to said heating device including sliding contacts (18, 19) on the outside of said screw shaft (11),
- a plurality of axially spaced openings (23) along the axial length of said screw shaft shell, said openings being equally spaced around the circumference of said shell and connecting said cavities of said screw shaft (14) and of said screw flight (13) to one another.
Dependencies are inferred from the claim text.