Renseignements généraux

Nº de série

S/O

Nº de partie

1

Nombre total de parties

1

Ou

S/O

Brevets

S/O

Description générale

metal hygrometer casing with metal dial cover, synthetic window/ bundle of possible hair/ metal frame and radiation shields/ synthetic covered electrical cable

Dimensions

Remarque : Cette information reflète la taille générale pour l’entreposage et ne représente pas nécessairement les véritables dimensions de l’objet.

Longueur

54,0 cm

Largeur

34,0 cm

Hauteur

82,0 cm

Épaisseur

S/O

Poids

S/O

Diamètre

S/O

Volume

S/O

Lexique

Groupe

Météorologie

Catégorie

Mesure hygrométrique de l'atmosphère

Sous-catégorie

S/O

Fabricant

Ou

Lambrecht

Pays

Allemagne

État/province

Inconnu

Ville

Göttingen

Contexte

Pays

Canada

État/province

Inconnu

Période

1980's to mid 2000's; this instrument was apparently in use for twelve years (Ref. 5)

Canada

A humidity gauge of the type used by the Meteorological Service of Canada to gather relative humidity data from across Canada. Part of a large collection of meteorological instruments acquired from the Meteorological Service of Canada (previously Atmospheric Environment Service) by the CSTM since 1967. MSC is the government agency responsible for collecting and disseminating meteorological data and forecasts in Canada. It was founded in 1871 in Toronto where it is still headquartered. The MSC was originally on the University of Toronto downtown campus but moved to Downsview in 1971 on land owned by UofT. The headquarters houses laboratories, research facilities and calibration and instrument maintenance facilities (now largely contracted out).

Fonction

An instrument used to measure the relative humidity of the atmosphere, mounted in a frame and radiation shield for installation on an anemometer tower at an automated meteorological observing station.

Technique

An example of a hair hygrometer with mounting bracket and sun shield. The mount and shield supplied are typical of the installations at MAPS1 and IWD automatic station installations from about 1980 to the present (2004). A hygroscopic humidity element depends upon water causing mechanical swelling within a material such as human hair, intestine (goldbeaters skin), or nylon. Hair becomes longer as the relative humidity increases and shorter as it decreases. The hair hygrometer uses strands of blond human hair with the oils carefully removed. Bundles of this hair are attached to levers that magnify small changes in the length of the hair. The hair hygrometer, developed by Horace Bénédict de Saussure in 1775, was the first reliable humidity sensor. A pen attached to the hair bundles and clock driven cylinder, known as a hygrograph, provides a record of the changes in relative humidity over time. In Canada the hair humidity sensors can be found in the Lambrecht 252C hygrothermograph (1989.0094). The Pernix sensor which is used at some remote automatic stations has the hairs connected to a potentiometer so that its resistance changes with changes in humidity. The advantage of the Pernix was that it does not require power. Under very dry conditions these sensors will stop reacting until very humid conditions occur again. Also their response time is very slow particularly at cold temperatures (Ref. 2).

Notes sur la région

Inconnu

Détails

Marques

black lettering on white dial face reads in part ' % rel. Feuchte/ 560473/ 5-100-5' with scale for 0 to 100 and 'PERNIX/ Made in Germany'

Manque

appears complete

Fini

textured blue painted casing exterior/ grey painted dial cover with white face, colourless transparent cover/ glossy white painted MSC frame/ glossy white painted MSC radiation shield with black painted interior/ white wire covering

Décoration

S/O