READS REMOTE TEMPERATURES

Press, Volume CIV, Issue 30841, 28 August 1965, Page 17

READS REMOTE TEMPERATURES

Equipment which gives remote readings of temperature at different levels at any or all of six alpine stations has been built by the industrial development department of the University of Canterbury and put into use by the Forest Sendee.

Although carried by cable up to three miles, the readings are accurate to .2 degrees centigrade, a result never before achieved in this country. Earlier equipment showed errors up to 20 degrees. The Forest Service has been studying the effects of temperature above the timberline. on the line, and below It in the bush. It was not previously possible to get accurate continuous readings at all times and in all weathers. The new equipment gives this visually at a base station in the Broken river region, and it is so constructed that eventually card-punching gear can be attached directly to it to give records which can be processed at first by sorting machines and eventually by computer. Six thermometer stations at different levels each record air, ground, and soil temperatures, and at the base three miles away any of these readings can be selected on a dial in much the same way as is done in tuning in to a radio station.

The industrial development department’s design is such that the equipment can also test itself, checking for shortcircuits or irregular resistance at any point in the cable. The basic elements are thermistors, which record a large change in electrical

resistance when temeperature changes. These were built in Germany, where the method has been used, but not with such accurate success as in Canterbury. The thermistors were sealed to the cable by special chemicals prepared in Canterbury. These joints are protected by neoprene sleeves specially made by a Christchurch factory. The main polythene-pro-

! tected cable was specially i made by a Christchurch cable I factory. With all these special i prescriptions errors through i cable faults have been virtually eliminated. I The installation will record ■ temperatures from 130 de- • grees Fahrenheit to 20 de- ’ grees of frost. Visually read at the base, these recordings • have given the Forest Service much useful information this

winter. When punch-card equipment is attached the range of research will be increased considerably. The only difficulty in the whole operation was caused by the weight of cable. Delivered in two lengths a mile and a half long to minimise the number of joints, it was a very heavy load to manhandle up steep mountain slopes.