Extension of Messrs. Negretti and Zambra's Works

Abstract

MESSRS. NEGRETTI AND ZAMBRA, whose high reputation for scientific and industrial instruments is well known, have just completed a fourth extension of their works consisting mainly of a double floor building of approximately 10,500 square feet. The first floor comprises a new electrical thermometer department and experimental department with an extension for aircraft instruments. In the assembly of certain electrical thermometers it is very desirable to have a dust-free atmosphere, and very special care has been taken to ensure cleanliness in this department. For this purpose, an air-conditioning plant is installed which supplies the shop with filtered air, and if required, heated air free from dust and dirt. The air is led through a comparatively large duct along the roof and into the shop through adjustable nozzles placed at intervals along one side of the building. As the whole building is practically airtight, a series of exhaust fans are provided in the window frames on the opposite side of the shop for exhausting the air. This ensures a flow of pure air across the shop with no entry of impure air. Consideration has also been given to the flooring to avoid dust, and this is a wood block floor of Austrian oak. The test room is separated from the main shop by partitions, and this is likewise kept dust-free. The equipment of the test room includes standard potentiometer, millivoltmeters, thermometer-testing baths, etc. The expansion has resulted also in an enlargement of the existing machine shop and a further expansion for the manufacture of mercury-in-steel thermometers.