Hotbox detector
US4068811A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 28, 1977 |
| Grant date | Jan 17, 1978 |
| Priority date | — |
| Expiry date | Apr 28, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S246/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for determining the temperature of railroad car wheel journals (i.e., "hotbox" detector) includes a sensor including a pyroelectric cell responsive to infrared radiation signals, which are focused onto the cell, to output voltage signals as a function of the radiation signals inputted thereto. The sensor exhibits a nonlinear gain response to different frequencies of input signals and compensation is provided by coupling the output of the sensor to a differentiating circuit which has a similar but relatively negative gain response. The output of the differentiating circuit is a substantial voltage replica of the infrared input signal and this voltage signal may be applied to a suitable utilization device such as one which records journal temperature and/or provides a suitable alarm when a sensed journal temperature exceeds a predetermined value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.