Who would use an Aneroid Barograph?
- Larger yachts and ships,
- Land based weather bureaus,
- Many are in use in the UK Met Offices and other European weather services, as well as by individual weather watchers, worldwide.
- Fischer barographs are used by navies and weather services, worldwide.
Measuring
- It uses a set of 7 aneroid capsules with a diameter of 62 mm made from copper-beryllium alloy. This material 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 bi metal components over the full measuring range and for temperatures between -30 to +40 °C (-22 to 104 °F).
- All contacts in the movements are jeweled to reduce friction.
Measuring Ranges
Measuring range used for altitude
955 to 1055 hPa
930 to 1030 hPa
905 to 1005 hPa
880 to 980 hPa
855 to 955 hPa 0 to 150 m above sea level
150 to 350 m above sea level
350 to 600 m above sea level
600 to 850 m above sea level
850 to 1,100 m above sea level
Clockworks
- Mechanical clockwork
- Can be shifted to take daily weekly measurements
- Revolution times changeable: daily revolution 25.6 h, weekly revolution 176 h, monthly revolution 783 h
- Autonomous operation 12 month with battery type LR6 autonomous operation 1 week
- Note that the mechanical clocks do not have a monthly mode.
- Weekly rotations are the most common used with barographs.
Quartz Clockworks
- Runs in 3 modes: daily, weekly, and monthly
Recording Instruments
- The recording instruments are delivered complete with fibre pens and a year's supply of recording charts.
- Weekly charts are the standard that are provided unless requested otherwise.
Dampening
- Fischer instruments are unique in offering an option on each model with enhanced dampening for barograph use at sea.
- After you chose your model and timing option, the extra dampening can be selected.
- There is no need for this option for land based operations.
Charts
- The paper charts are the same size for all models: 92mm tall by 302 mm long.
- Charts marked in inches of mercury are also available on request.
Registration Drum
- height 93 mm diameter 93.3 mm
- height of registration 80 mm
- chart division 1 hPa
Weight
4.5kgs
What is the Difference between models 267 models and the 287 models ?
in principle the function of both Barograph version is the same, the measuring & recording of the absolute air pressure.
Nevertheless there a some differences between 267M and 287M which causes the significant price difference:
The 267M has another housing with 5 glasses (faceted float glass), the 287M housing has only 4 glasses (closed cover).
Besides of this the mechanics are different. All parts of the movement of the 267M are made of polished brass, the 287M
has a black movement holder (aluminum), the transmission is also made of polished brass.
