Aneroid barographs are used to measure and record the history of atmospheric pressure. The measuring element in the Fischer barographs is a set of 7 aneroid capsules, manufactured of a copper-beryllium alloy that essentially eliminates age-hardening, hysteresis, and elastic after effects that could otherwise degrade the accuracy. The influence of temperature on the set of aneroid capsules and the transmission system is compensated by use of bimetal components over the full measuring range and for temperatures between -30 to +40 °C (-22 to 104 °F). All contacts in the movements are jewelled to reduce friction.
For each model there is a choice of mechanical wind-up clockworks or quartz clockworks, which can be shifted in an instant for daily, weekly or monthly revolution. The actual periods are 25.6 hrs. 176 hrs., and 783 hr. The recording instruments are delivered complete with fibre pens and a year’s supply of recording charts.
Fischer instruments are unique in offering an option on each model with enhanced dampening for barograph use at sea.
Models
225 Barograph with mechanical clockwork
225Q Barograph with quartz clockwork
227 Marine Barograph with mechanical clockwork
227Q Marine Barograph with quartz clockwork
Specification
Sensor
- 7 aneroid capsules ±0.7 hPa
Measuring ranges
- 955 to 1055 hPa 0 to 150 m above sea level - 930 to 1030 hPa 150 to 350 m above sea level - 905 to 1005 hPa 350 to 600 m above sea level
- 880 to 980 hPa 600 to 850 m above sea level - 855 to 955 hPa 850 to 1.100 m above sea level
Clockworks
- Mechanical drum recording clockwork according to DIN 58658
revolution times changeable: daily revolution 25.6 h,
weekly revolution 176 h
autonomous operation 1 week
- Electronic quartz clockwork
revolution times changeable: daily revolution 25.6 h, weekly revolution 176 h, monthly revolution 783 h
autonomous operation 12 month with battery type LR6
Registration drum
- height 93 mm diameter 93.3 mm
- height of registration 80 mm - chart division 1 hPa
Accessories (contained in delivery)
- 60 sheets of chart paper for weekly revolution - 2 pieces of fibre tips - battery type LR6 (electronically quartz clockwork)
