US 5,393,209 AGranted

Double-ended ceramic helical-rotor expander

AssigneeThe United States of America as represented by the United States Department of Energy

InventorsPeter B. Mohr, Wendell B. Myers

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Abstract

A ceramic helical rotor expander using a double-ended or tandem herringbone type rotor arrangement with bearing and seal assemblies remote from the hot gas inlets and especially capable of operating at an inlet temperature of above 1100.degree. C. The rotors are solid or hollow and bonded to hollow metal shafts, and mounted in a composite or simple prismatic casing. The rotors, casing and shafts are constructed from low expansivity materials. In the preferred embodiment the rotors are constructed of silicon nitride and the shafts constructed of an molybdenum alloy, with the metal shafts being supported in bearings and secured to synchronizing gears. The rotors and casing may be provided with coolant channels therein, and are constructed to eliminate the problem of end leakages at inlet temperature and pressure, and the need for high temperature bearings and seals.

Claims22

Dependent claims

A helical rotor apparatus comprising:

a casing including a body section and end sections, at least entire body section being constructed of reaction bonded silicon nitride;
a first pair of rotors interconnected at inner ends thereof and having helical lobes thereon, said lobes on one of said rotors interconnecting at a point with lobes on another of said rotors, said lobes on each of said rotors extending at an angle from said interconnecting point thereof;
a second pair of rotors interconnected at inner ends thereof and having helical grooves thereon, said grooves on one of said rotors interconnecting at a point with grooves on another of said rotors, said grooves extending at an angle from said interconnecting point thereof;
said lobes of said first pair of rotors being constructed to extend into said grooves of said second pair of rotors;
said first pair of interconnected rotors being secured to a first shaft means;
said second pair of interconnected rotors being secured to a second shaft means;
a first pair of bearing assemblies;
a second pair of bearing assemblies;
said first shaft means being mounted in said end sections of said casing via said first pair of bearing assemblies;
said second shaft means being mounted in said end sections of said casing via said second pair of bearing assemblies;
said bearing assemblies each being located adjacent outer ends of said interconnected rotors;
said first shaft means and said second shaft means being interconnected by gears, and one of said shaft means being adapted to be connected to an associated mechanism;
and
said body section of said casing being provided with at least one intake opening and a plurality of exhaust openings, said intake opening being located in alignment with said inner ends of each pair of interconnected rotors and with said interconnecting points of said lobes and grooves on said rotors defining an intake zone, said exhaust openings being located adjacent said outer ends of said interconnected rotors.

11 more elements

A herringbone rotor type expander into which hot medium is directed for expansion therein and thereby driving an output shaft, comprising:

a case including a pair of end plates;
at least said entire case being constructed of reaction bonded silicon nitride;
a pair of interconnected male rotors secured to a first shaft;
a pair of interconnected female rotors secured to a second shaft;
said male rotors and said female rotor being positioned in said case and said first and second shafts extending through bores in said end plates;
one of said shafts constituting said output shaft;
a bearing assembly being positioned in each of said bores in said end plates, extending around said shafts, and located at outer ends of said interconnected rotors;
synchronized gearing connected to one end of each of said first and second shafts;
each of said interconnected male rotors provided with a plurality of outwardly projecting members, an inner end of each of said projecting members on one of said male rotors being in aligned abutment with inner ends of each of said projecting members on another of said male rotors and extending at an angle therefrom;
each of said interconnected female rotors provided a plurality of grooves therein,, an inner end of each of said grooves on one of said female rotors being in aligned abutment with inner ends of each of said grooves on another of said female rotors and extending at an angle therefrom;
said case including a centrally located inlet and a pair of outlets, said centrally located inlet being positioned in fluid communication with said inner ends of said projecting members and said grooves so as to define and inlet zone, each of said pair of outlets being located adjacent outer ends of said projecting members and said grooves;
whereby hot medium directed through said centrally located inlet expands between said male and female rotors causing rotation thereon and rotation of said output shaft, and exhausts through said pair of outlets.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/038,421Filed 29 Mar 1993
Granted: 28 Feb 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

F01C 1/16
With toothed rotary pistons: with helical teeth, e.g. chevron-shaped, screw type
F01C 1/082
Of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing: details specially related to…
F01C 11/002
Combinations of two or more machines or engines, each being of rotary-piston or oscillating-piston type: of similar working principle
F01C 21/003
Component parts, details or accessories not provided for in groups F01C1/00 - F01C20/00: systems for the equilibration of forces acting on the…