Thermo Hygrograph

The Thermo-hygrograph is designed for measuring and recording atmospheric Temperature• & Humidity as a function of time on recording chart. The Thermo-hygrograph uses a simple mechanisms for measuring both temperature & humidity. Measurements are recorded onto a rotating paper chart. A rotating drum is driven by a precision electronic Quartz clock. The chart paper used on the drum. recorder has two separate sections, an upper section• for temperature and a lower section for humidity. Both sections have the zero or low-scale at the bottom edge of the scale and the full-scale or high-scale at the upper edge.

A curved, bi-metal element bends and straightens as the air temperature around it changes. The bending of the curved element moves the temperature pen arm and results in the recording on the chart paper.

Relative humidity measurements are made with a human hair sensing element. Changes in the moisture content of the air causes the length of the hair to change. The hair is attached firmly to the frame of the Hygro thermograph so that the expansion and contraction of the hair can be translated into the movement of the pen arm.

Individual models Thermograph & Hygrograph are also available. Instrument is made as per IS specifications.

Parameter	Temperature	Humidity
Sensing Element	Bi-metallic Assembly	Human Hair Bundle
Range	-20 to 60 Degree C	O to 100 % RH
Accuracy	± 1 Degree C	± 2% (Above 20%)
Recording Resolution	0.5 Degree C	1%
Housing Material	FRP / Aluminium / Metal
Recording Mechanism	Drum driven by Quartz Clock