Road condition monitoring devices

• US 3,891,979 A
• Filed: 10/23/1973
• Issued: 06/24/1975
• Est. Priority Date: 11/07/1972
• Status: Expired due to Term

• Current Assignee: Horst Oehler, Otto Paul Braun
• Original Assignee: Horst Oehler, Otto Paul Braun
• Inventors: Braun, Otto Paul, Oehler, Horst
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US05/408,377
• Time in Patent Office: 609 Days
• Field of Search: 340/234,235
• US Class Current: 340/581
• CPC Class Codes: G01W 1/06 giving a combined indication of weather conditions catathermometers for measuring "cooling value" related either to weather conditions or to comfort of other human environment G01W1/17; computers per se G06
• CPC Class Codes: G01W 1/14 Rainfall or precipitation gauges measuring volume in general G01F
• CPC Class Codes: G08B 19/02 Alarm responsive to formation or anticipated formation of ice

Abstract

A device for detecting the danger of black ice on the roads has at least one road temperature sensor, a moisture sensor and a salinity sensor. Electrical circuitry converts the salt content of moisture on the road surface, as measured by the salinity sensor in the form of a conductivity cell, into the freezing point of the road moisture and compares this freezing point with the actual road temperature. If the latter is the lower there is a danger of black ice, unless the moisture sensor shows that the road is dry, and an audible and/or visible signal of the danger is produced. Gritting of the road can then be promptly undertaken. A second road temperature sensor can be used to switch on parts of the device when the temperature falls below a value slightly above 0*C.

Claims

1. A device for detecting the danger of ice or snow on roads, comprising an electrical ground temperature sensor, an electrical salt content sensor, said sensors being adapted to be applied to the road surface, means connected to said sensors for comparing the ground temperature with the freezing point of the particular salt soluton present, and means for producing a warning signal when the ground temperature approaches the freezing point of the solution on the road surface.

2. The device of claim 1 further comprising means for indicating the ground temperature.

3. A device according to claim 1, in which said warning signal is a visible warning signal for vehicle drivers.

4. A device according to claim 1, which further comprises a moisture sensor which is adapted to be applied to the road surface and which is connected to a logical gate to provide said warning signal only in the presence of moisture.

5. A device according to claim 1, in which at least one of said sensors has a heating system.

6. A device according to claim 5, in which the heating system is controllable by means of said electrical ground temperature sensor.

7. A device according to claim 5 further comprising a second electrical ground temperature sensor for controlling said heating system.

8. The device of claim 1 further comprising means for indicating the freezing temperature of the particular salt solution present.

9. A device according to claim 1 including radio means for transmitting signals between parts of the device which are disposed at points spatially separated from one another.

10. A device according to claim 1 in which said electrical salt content sensor includes a chamber adapted to be filled with salt solution from the road surface and at least a pair of electrodes vertically disposed in said chamber.

11. A device according to claim 10, in which said chamber has an overflow located above the uppermost one of said electrodes.

12. A device according to claim 10 in which said salt content sensor includes two separate electrode units, said electrodes of the salt content sensor being disposed in said separate electrode units.

13. A device according to claim 12, in which said two electrode units are identical.

14. A device according to claim 12, in which an alternating current source for said salt content sensor is provided and in which each of said electrode units contains two said electrodes of which one is connected to said alternating current source, the output signal of the salt content sensor being present at the other electrode.

15. A device according to claim 10 which further comprises a temperature sensOr disposed in said chamber and adapted to compensate for the influence of the temperature of the salt solution upon the conductivity thereof.

16. A device according to claim 1, which further comprises a collecting bath, said bath having an overflow and defining a chamber to be filled with salt solution and in which said electrical salt content probe includes at least a pair of electrodes disposed in said chamber.

17. A device according to claim 16, further comprising means for flushing the chamber by the liquid running into the chamber.

18. A device according to claim 1 in which the warning signal is provided by alarm means and a transmitter whose signal serves to trigger said alarm means.