DE202009016129U1 - Temperature scanner for asphalt surfaces - Google Patents

Abstract

Contraption ( 1 ) for measuring the temperature of the surface of hot asphalt, consisting of a moving infrared temperature measuring head (1), a motor (2) for moving this sensor and an evaluation.

Description

Field of use:

The The invention relates to a temperature measuring system for measuring the asphalt temperature on a road paver while of the installation.

State of the art:

Become streets newly built or repaired, then on the gravel substructure several layers of hot Asphalt applied. This happens with so-called pavers. These Mobile machines have storage tanks, conveyors and and compaction systems. The hot asphalt is at temperatures distributed from 100 to 130 degrees, put on the road and compacted.

to quality control The temperature of the laid asphalt should be recorded behind the paver and saved. Thus it is possible, with later damages of the surface verify whether errors are pre-programmed during installation due to incorrect temperatures were.

From the "Texas Department of Transportation "was a system developed with many individual infrared temperature sensors. These are on a beam that is transverse to the direction behind the Vehicle is mounted. arranged. The distance from sensor to sensor is about 33 cm, that is for one Scanning width of 4 meters needed you already have 12 sensors. about an interface, the individual sensors are queried, graphically and numerically displayed and saved.

The Disadvantages of this system consist of the with the number of sensors associated costs and the unwieldiness of the attachment of the bar.

task this utility model is to describe a system which avoid the aforementioned disadvantages and ease of use guaranteed at moderate cost.

Solution:

Instead of Many sensors use a single measuring element which for longer distances and fast measurements is suitable. About suitable mechanical deflections the one-dimensional infrared radiation is distributed on a surface and thus gives a two-dimensional measurement (scanner).

Out The industry already has temperature scanners on the market. These however, are often overspecified and therefore too expensive. Here are the infrared rays over a rotating mirror on a stationary sensor transmitted and evaluated.

The solution described here uses a motor that makes the entire measuring head in an angular movement offset and thus dispensed with the mirror. Be about suitable procedures both the energy to operate the sensor and the data from the rotating to the fixed part. As an engine can both a DC motor with gearbox as well as a stepper motor used become. The stepper motor is a bit more expensive to control, but can be used without gear.

at Using a DC motor, an encoder is used for position feedback Use, for the Stepper motor variant, an index signal at zero crossing (middle) is sufficient.

There the sensor is not completely rotated, but only one Angle of plus or minus 70 degrees (from the center of) moves, is sufficient in the simplest Case for the power supply and the measuring signal a cable connection from the stationary part to the movable sensor head. By the permanent Movement, however, the cable is heavily loaded and therefore error prone. Better is to ensure the energy supply contactless. Suggested an inductive transmission like an electric toothbrush.

The Data can easily be transferred digitally via infrared cutters.

The Raw value determination takes place in the sensor element. This transmits the data to the evaluation unit where the data is linked to the angles and associated with a distance measurement associated with the individual areas are.

1 schematically shows the structure of such a sensor.

In 2 is shown how the Infrarotmeßstrahl first moves from the center to the left and thus -n measuring points (-1, -2, ... -n) generated. After detecting the temperature drop, it swings back and generates further measured values in the + n direction.

at a scan time of 1 second and a measuring distance of 10 cm, the time constant maximum 20 msec. be to scan a width of 5 meters. Sensors with a time constant of 10 msec. are too moderate Costs available on the market.

Claims (5)

Contraption ( 1 ) for temperature measurement the surface of hot asphalt consisting of a moving infrared temperature probe ( 1 ), a motor ( 2 ) to move this sensor and an evaluation. Apparatus for measuring the temperature of asphalt surfaces, at the sensor moves transversely to the direction of travel and thus the surface scans line by line. In conjunction with the speed results a zigzag-shaped Record the temperatures. Device for temperature measurement, in which the sensor head scans the surface to be measured by means of a suitable mechanism in such a way that the measurements start when the sensor is upright ( 2 ). If the sensor is now turned in one direction, the measuring point moves to the side. At the angle where a rapid drop in temperature is measured, the scan area is over, changing direction and thus reversing towards the center. The same process will now continue on the other side. This results in an approximately uniform swinging back and forth of the temperature sensor. Apparatus for measuring temperature, the surface of hot Asphalt, consisting of a stepper motor, the infrared sensor rotating moves. Device for measuring the temperature of the surface of hot asphalt, consisting of a DC motor with gearbox that turns off the infrared sensor. and swings around.