| All Patents in class 237/12.1 |
Patents 1 -
10
of 11
      |
| Picture | Number | Date | Patentee | Title |
| | 33,497 | Oct. 15, 1861 | P. Shaw | Air Engine |
 | 100,211 | Feb. 22, 1870 | B.F. Sturtevant | Heating and Ventilating Apparatus |
 | 193,086 | Jul. 17, 1877 | B. Holly | Steam Apparatus |
 | 260,097 | Jun. 27, 1882 | B. Holly | Apparatus for Supplying Steam |
| | 529,452 | Nov. 20, 1894 | M. Lorois | Gas Motor |
| | 575,720 | Jan. 26, 1897 | J. Ledent | Gas Engine |
| | 2,189,895 | Feb. 13, 1940 | F.P. Grutzner | Heating and Ventilating System |
| | 2,200,379 | May 14, 1940 | R.D. Williams | Utilization of Waste Engine Heat |
| | 2,208,157 | Jul. 16, 1940 | F.P. Grutzner | System for Recovering and Utilizing Waste Heat |
| | 2,256,303 | Sep. 16, 1941 | R.D. Williams | Recovery and Utilization of Waste Engine Heat |
