US 7,461,523 B2
Apparatus for contactless measurement of the temperature in a melting furnace
Markus Mersmann, Stelle (Germany); and Heinz Lambrecht, Bremen (Germany)
Assigned to BEGO Bremer Goldschlägerei Wilh. Herbst GmbH & Co., Breman (Germany)
Filed on Oct. 12, 2005, as Appl. No. 11/247,595.
Claims priority of application No. 10 2004 049 789 (DE), filed on Oct. 12, 2004.
Prior Publication US 2006/0075784 A1, Apr. 13, 2006
Int. Cl. C03B 18/22 (2006.01)
U.S. Cl. 65—29.21  [65/158; 65/162] 18 Claims
OG exemplary drawing
 
1. A melting furnace having a crucible and an apparatus for contactless temperature measurement of a melting charge located in the melting crucible (2) inside the melting furnace by means of a pyrometer (5) with an optical system (8) and at least one sensor (6) optically connected to said optical system (8), wherein said optical system (8) can be directed by means of a sight glass (18) onto at least one section of the melting crucible (2),
wherein the optical system further comprises
a tube (17) which is connected at its upper end (31) to the sight glass (18), and extends into a melting chamber (11) of the melting furnace and points in the direction of the melting crucible (2), and where the tube has a lower end that is open to the crucible and has a length and inner diameter sufficient to inhibit smoke and particulates from entering the tube.