Abstract: A fume hood comprising: a hood, a work chamber, and a front wall formed with an opening toward an indoor environment; an air supply system, and an air exhaust system to discharge air that enters the work chamber through a front opening and enters the work chamber through the air supply system, out from the work chamber; the air supply system provided with at least one air supply outlet in an upper portion and a lower portion of the hood, and the air supply outlet supplying air towards the work chamber. The fume hood can reduce energy consumption of air conditioning and suppress overflowing of harmful substances in the work chamber, with a low installation cost and a high consistency of product quality.

Abstract: The present invention provides a steady flow structure and a ventilation apparatus having the steady flow structure.

Abstract: A ventilation valve, comprising a cylindrical valve body (1), a gear box (2), a plurality of fan-shaped vanes (3) and a drive device (4), the gear box (2) being arranged in the center of the valve body (1), and a geared mechanism being provided inside the gear box (2). The drive device (4), by means of a geared drive mechanism, cause the vanes (3) to rotate in a same direction, each around its own central shaft; the vanes (3) are arranged within the valve body (1) in a uniform distribution; the geared mechanism comprises a first central gear (23) and a second central gear (24) fitted on a same supporting shaft (25); between the first central gear (23) and the second central gear (24) are provided a plurality of gears, one each of which is arranged at the end of one of said central shafts which extends to within the gear box (2), each of said gears engaging with both said first central gear (23) and said second central gear (24).

Abstract: The present invention provides a steady flow structure and a ventilation apparatus having the steady flow structure.