Ventilation cabinet

A system, comprising:

• a fume hood and a top module above the fume hood, the fume hood comprising
• a hood including an upper portion;
• a lower portion;
• a work chamber;
• a rear wall;
• a front wall formed with an opening toward an indoor environment;
• an air supply system, configured to connect to a building air supply channel to supply air to the work chamber;
• an air exhaust system, configured to connect to a building air exhaust channel to discharge air that enters the work chamber, wherein
• the air supply system comprises a first air supply outlet in the upper portion of the hood and inside the front wall for supplying air into the work chamber, a second air supply outlet in the lower portion of the hood for supplying air into the work chamber, and a third air supply outlet in the upper portion of the hood and outside the front wall for supplying air into the work chamber and toward the lower portion of the hood;
• a first air supply channel located on the upper portion of the hood and configured to connect an air supply blower and an air supply valve to the first air supply outlet;
• a second air supply channel located on the lower portion of the hood and configured to connect the air supply blower and the air supply valve to the second air supply outlet;
• a third air supply channel located on the upper portion of the hood and configured to connect the air supply blower and the air supply valve to the third air supply outlet;
• a sliding window located between the first air supply channel and the third air supply channel, and configured to slide within the front opening and for adjusting an open area of the front opening;
• and
• a hollow left side wall and a hollow right side wall, wherein the first air supply channel, the second air supply channel and the third air supply channel are communicated through the hollow left and right side walls;
• the top module comprising the air supply blower and the air supply valve for the air supply system and an air exhaust blower and an air exhaust valve for the air exhaust system,
• wherein the air supply blower and the air exhaust blower are power adjustable blowers, the air supply valve and the air exhaust valve are opening degree changeable valves, and wherein,
• the fume hood further comprises:
• a position sensor for detecting a position of the sliding window, an air velocity transducer for detecting velocity of air entering into the work chamber from the front opening, an infrared detector for detecting whether operators are in a disposed region;
• and
• a control unit, that connects with the position sensor, the air velocity transducer, the air supply valve and the air exhaust valve, and adjusts the opening degree of the air supply valve and the opening degree of the air exhaust valve based on detections of the position sensor and detections of the air velocity transducer,
• wherein the air exhaust system further comprises an air exhaust region, which is provided on the upper portion of the hood and close to the rear wall of the hood, said air exhaust region extending in a left and a right width direction of the hood, and configured to connect with the air exhaust blower and the air exhaust valve, and
• wherein the lower portion of the hood includes at least one hood base, the hood base including an inner cavity that connects with the air exhaust region through a hood base air exhaust channel, said hood base air exhaust channel disposed in at least one of the hollow left and right side walls and extending along an up and down direction closing to the rear wall.