David P. Keller

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Morrisville, PA, US

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Patents Grantslast 30 patents

Information Patent Grant
Muffle calciner having counter-rotating screw conveyors
- Patent number 4,222,987
- Issue date Sep 16, 1980
- Cities Service Company
- David P. Keller
- F27 - FURNACES KILNS OVENS RETORTS