HYGROGRAPH

This instrument is manufactured as per IS: 5900-1970. The humidity sensor consists of a bundle of Human Hair held between two adjustable jaws, the whole assembly being mounted on a hair movement plate. The variations with length of the hair stands due to changes in the relative humidity are measured by the displacement of the centre of the hair strands transmitted by a lever and a pair of cams to the pen arm so that the movement of the pen is a linear function of the relative humidity. Available with mechanical clock.

The Thermoygrograph is itended to measure and to record air temperature and relative humidity verses time on a double field paper recorder chart. It is used in Meteorological service, as well as in drying rooms, stores, measuring rooms etc. in order to measure air temperature the metal Thermal Expansion Effect has been utilised. The sensor is a thermobimetalic strip consisting of two layers of Alloys having different co-effecients of expansion, one end is fixed and other end connected to the linkage. Bending stresses arising within the strip due to temperature variations results in deformation of the strip & alter the position of its free end. The displacement is transmitted on to the writing pen by means of linkages and resulted in a diagram being platted on the olwer field of the recorder chart. Similarly to measure the relative air humidity and hydroscopic properties of prepared human hair band whose one end is fixed in a hosder and other end is connected to a linkage variatin in length of human band is transmitted on to writing pen by linkages. The Motion of which results in a diagram being plotted on the higer field of the recorder chart.

Also available with mechanical clock.