Circular chart recorder working

A circular chart recorder is used to record data in a circular chart.

Main components in the circular chart recorder:

It consists of a measuring element, an operating mechanism, a chart drive, and a recording device that can be installed on a single panel.

Usually, the chart is mounted on a flat supporting plate and fastened by spring clips in position to prevent curling. A helical pressure tube or any other element could be the measuring element.

The operating mechanism consists of helicopters a and b and connectors c which transmit motion from the measuring element to the recording device.

Inking system:

The fibre tip pen capsules are used by the writing system. Where two or more measuring systems are available, different colour tints are used to distinguish the traces.

The tip of the fibre is protected by a rubber cap that should be removed by pulling in line with its length, only grabbing the end and twisting gently.

Chart drives:

A chart drive mechanism drives the chart paper, mounted on a clamping hub. A mechanical spring wound, battery operated or electrically powered mechanism will be the chart drive depending on the requirement.

Linkage and pivot attachment:

Whether the measuring system is temperature, pressure or differential pressure, the instrument employs a similar connection attachment.

The diagram above is provided to supplement the figures presented throughout this manual to illustrate the terminology and correct arrangement to ensure free movement of friction linkage and thus accurate pen traces.

The assembly of recording pen mechanism, mounted via a bracket on the base plate, provides attachment to the elements of measurement. Each measuring element provides output movement via an adjustable take-off assembly arm or direct drive arm.

Either type is terminated in a tapped hole to which is attached the adjustable horizontal link via a shoulder screw forming a pivot without excess side movement for smooth friction free movement.

At its opposite end, the adjustable horizontal connection is screwed into the ratio post, providing a smooth pivot without excessive free movement or playing, eliminating hysteresis.

The ratio post provides an adjustable pivot point for the adjustable horizontal connection and the span adjustment is thus provided by the position of the ratio post in the pen bracket and clay through the slot.