A pressure measuring device can be set up in the kitchen. When the kitchen exhaust fan is all working and the negative pressure increases, the return air electric valve closes, the return air fan stops, and a large amount of restaurant air is supplied to the kitchen; when a small amount of When the exhaust fan is on or not working, and the negative pressure is not very large, the electric return air valve opens and the return air fan starts to prevent all the air from the air conditioner being exhausted. Two units are used to serve the restaurant and the kitchen respectively. The kitchen is equipped with fresh air. The DC system directly supplements the exhaust air from the kitchen stove, while the restaurant is a new air system with primary return air. This solution can ensure the air conditioning effect of the restaurant and kitchen, and the kitchen and restaurant systems do not interfere with each other. The disadvantage is that the initial investment is relatively large for gas collection ( Smoke) hood Gas (smoke) hood is generally processed as a whole, including filtering, oil collection, water collection and other equipment, and is mostly made by professional kitchen companies. Its appearance should be uniform, beautiful, and easy to clean. During kitchen ventilation, a certain amount of fresh air needs to be added. On the one hand, it can balance the air pressure and avoid excessive negative pressure in the kitchen (generally should not be greater than 5Pa). On the other hand, it can reduce the temperature in the kitchen. , improve the working environment. For the collection of cooking fume, there are three main types of gas (smoke) hoods used. Simple gas hoods without oil baffles and air supply equipment are suitable for various flexible and mobile places, easy to process and install, and cheap. However, since there is no air supply equipment, the air collection effect is relatively poor, which easily causes the oil smoke to swirl in front of the kitchen staff, and easily causes oil droplets to scatter. The air collection hood containing the oil baffle and air supply equipment can better collect the gas generated during the cooking process. The oil fume and oil droplets do not scatter. As long as the air supply volume is reasonable, the air quality at the kitchen operator's work surface will be good. However, the installation requirements are higher and the investment is larger. The design principle of the water-carrying and gas-collecting (smoke) hood is to form a water curtain circulation, which collides with the oil fume to achieve the purpose of purifying the oil fume. The key to affecting the effectiveness of the water transport gas (smoke) hood is to form a continuous water curtain, and the circulating water system needs to be cleaned regularly. ?