Claims
- 1. A process for forming a regenerator assembly comprising the steps of mounting a glass ceramic cylindrical regenerator core and a metallic ring in a fixture with the ring surrounding the periphery of the core in radially spaced relationship, an annular space thus being defined between the periphery of the core and the inside diameter of the ring, inserting in the annular space at least one heat shrinkable element, injecting elastomeric material in the annular space surrounding said element, and curing said elastomeric material with heat to shrink said element and form a cavity in said elastomeric material to form a torque transmitting path between the ring and the core with sufficient compliance to resist development of excessive stresses in the core.
- 2. The process as set forth in claim 1 wherein the step of injecting elastomeric material into said annular space is preceded by the steps of blending glass fibers with the elastomeric material and, cleaning and priming the surface of the core and the surrounding surface of the ring.
- 3. The process as set forth in claim 1 wherein said element is in the form of tubing arranged in tangential disposition around the periphery of said core and in a geometric pattern that allows one tubing portion to be radially offset with respect to the other, whereby a direct radial force transmitting path between the ring and the core is interrupted by the spaces, the force distribution pattern thereby including oblate force vectors as radial and tangential forces are distributed through the elastometric material.
- 4. The process as set forth in claim 3 wherein the step of injecting elastomeric material into said annular space is preceded by the steps of blending glass fibers with the elastomeric material and cleaning and priming the surface of the core and the surrounding surface of the ring.
- 5. The process as set forth in claim 1 wherein the step of injecting the elastomer is preceded by the step of inserting in the annular space surrounding the core a plurality of spheres formed of heat shrinkable material, said spheres when surrounded with elastomeric material creating cavities in the elastomeric material as the elastomeric material is cured.
- 6. The process as set forth in claim 5 wherein the step of injecting elastomeric material into said annular space is preceded by the steps of blending glass fibers with the elastomeric material and cleaning and priming the surface of the core and the surrounding surface of the ring.
GENERAL DESCRIPTION OF THE INVENTION
REFERENCE TO RELATED DISCLOSURE
This disclosure is related to co-pending patent application, Ser. No. 864,078 filed concurrently herewith by V. Durga Nageswar Rao, entitled "REGENERATOR AND DRIVE GEAR CONSTRUCTION." That application is assigned to the assignee of this application.
Our invention relates to methods for making rotary regenerators for use with an external combustion engine, such as a gas turbine engine, where heat is recovered from the engine exhaust and transferred to the engine intake gases to raise the temperature of the intake gases thus improving combustion efficiency of the burner for the engine. The regenerator core constructed of a glass ceramic material (2M.sub.g O.2Al.sub.2 o.sub.3.5SiO.sub.2) in the form of a cylinder is rotatable about its central axis during operation. The cylindrical core is surrounded by a ring gear which powers a regenerator, and the ring gear is yieldably connected to the ceramic core by elastomer material.
The ring is formed of steel and its rate of thermal expansion differs substantially from the rate of thermal expansion of the glass ceramic regenerator core. The elastomeric material accommodates differential rates of expansion that occur during operation of the regenerator as well as during the processing of the core and the ring gear assembly. Increased compliance of the ring gear with respect to the core is achieved thereby preventing an undesirable radial force transfer between the ring gear and the core which would tend to cause failure of the glass ceramic material of which the regenerator core is formed. This is done without reducing to an unacceptable level the ability of the elastomer to transmit tangential forces between the ring gear and the core.
The compliance of the ring gear with respect to the core during differential expansion is achieved by providing a space or cavity within the elastomer at strategic locations. These cavities permit compliance in both a radial direction and in a tangential direction. As the ring gear is displaced radially relative to the core by reason of differential rates of expansion and as the ring gear is displaced relative to the core in a tangential direction by reason of the driving forces transmitted between them, excessive stresses in the glass ceramic of the core are eliminated and cracking of the regenerator core is avoided.
US Referenced Citations (10)
Foreign Referenced Citations (2)
| Number |
Date |
Country |
| 243518 |
Dec 1925 |
GBX |
| 1308168 |
Feb 1973 |
GBX |
Patent Grant
4170620
