Chart recorder

A chart recorder is an electromechanical device that records an electrical or mechanical input trend onto a piece of paper (the chart). Chart recorders may record several inputs using different color pens and may record onto strip charts or circular charts. Chart recorders may be entirely mechanical with clockwork mechanisms or electro-mechanical with an electrical clockwork mechanism for driving the chart (with mechanical or pressure inputs) or entirely electronic with no mechanical components at all (a virtual chart recorder).

They are built in three primary formats. Strip chart recorders have a long strip of paper that is ejected out the side of the recorder. Circular chart recorders have a rotating disc of paper that must be replaced more often, but are more compact and amenable to being enclosed behind glass. Roll chart recorders are similar to strip chart recorders except that the recorded data is stored on a round roll, and the unit is usually fully enclosed. Dickson is the largest US manufacturer of circular chart recorders.

Chart recorders pre-dated electronic data loggers which have replaced them in many applications.

A patent for a 'Pressure Indicator and Recorder' was issued to William Henry Bristol, on September 18, 1888^[1]. Bristol went on to form the Bristol Manufacturing Company in 1889. The Bristol Company was acquired by Emerson Electric Company in March 2006, and continues to manufacture a number of different electro-mechanical chart recorders, as well as other instrumentation, measurement, and control products.

The first chart recorder for environmental monitoring was designed by American inventor J.C. Stevens while working for Leupold & Stevens in Portland, Oregon and was issued a patent for this design in 1915^[2]. Chart recorders are still used in applications where instant visual feedback is required and/or where users do not have the need, opportunity or technical ability to download and view data on a computer or where no electrical power is available (such as in hazardous zones on an oil rig or in remote elecological studies). However, dataloggers' decreasing cost and power requirements allow them to increasingly replace chart recorders, even in situations where battery power is the only option.

See also

• Barograph
• Electrocardiograph
• Polygraph
• Seismograph
• Thermo-hygrograph

References

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