A Barogram is the finished record traced by a barograph or similar meteorological instrument. The better the trace on your barograph chart the easier it is to read accurately. Metcheck specialise in supplying traditionally made Barographs and Barograph consumables such as charts, pens and ink. We often get asked for best practice advice so if you are new to using a Barograph for pressure measurements or have inherited a family heirloom the following steps may help when it comes to setting or calibrating your instrument.
Traditional barographs which use a metal pen with ink reservoir which can sometimes be substituted for a modern fibre nib which hold their own ink supply. A metal pen will require a drop or two of ink every 2 weeks or so to draw an even line. If you are putting more than two drops a week into your metal pen or your barograph trace is blotting follow these simple checks to improve your records.
1. What type of paper are you using?
Barograph charts must be of a special grade of paper that will not soak up the recording ink. Photocopies of existing charts will not do.
2. What type of ink are you using?
Barograph ink is a special slow drying / slow evaporating product that has been specifically designed for chart recorders. Using any standard type of ink can result in a horrible mess!
3. Is your pen in working order?
An old metal pen may need cleaning carefully to get it back to working order. If your metal nib is rusty or corroded it will need replacing. Metcheck metal barograph nibs can be adjusted by altering the gap between the points carefully. The two halves of the nib bucket should be of even length, the wider apart they are the fatter the line is drawn. It is common with new nibs or nibs that have not been used for some time to be dry on the ends and even with ink in them they will not draw a line. As with a fountain pen the Metcheck barograph nib works by capillary action. It is best practice to start a new or very dry metal nib by using a small needle or pin to break the surface tension of the ink, once started the nib will continue to draw a line until the ink is exhausted.
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Take the chart currently mounted on your barograph drum and look along the edge to check for a product code or chart reference. If there is no reference, try these tips.