Regulating valves for ventilation are core control components in ventilation and air conditioning systems. They control air volume and pressure by adjusting the cross-sectional area of air ducts, realize air distribution and working condition regulation of the system, and have the functions of regulation, shut-off and backflow prevention. Widely used in building HVAC, industrial ventilation and other scenarios, they are divided into several commonly used types according to functions and structures.

Air volume regulating valves are basic models, including single-blade and multi-blade types; the latter is further classified into opposed and parallel blade types. They adjust air volume through blade angles, featuring a simple structure and a wide regulation range, and are suitable for air volume distribution in general air ducts. Some with sealing structures can achieve semi-shut-off. Fire and smoke control valves are special valves combining fire protection and ventilation, with a built-in fusible alloy (fusing at 70℃). They regulate air volume under normal conditions and automatically close when the alloy fuses in case of fire, blocking the spread of fire and flue gas. They are usually installed on air ducts at the junctions of fire compartments.

Smoke exhaust fire valves are adapted for smoke exhaust systems, remaining closed in normal state and opening manually or electrically during smoke exhaust. When the flue gas temperature reaches 280℃, the fusible part fuses and the valve closes automatically to prevent fire from spreading to smoke exhaust ducts, serving as a key component of fire smoke exhaust systems. Check valves, also called non-return valves, include swing and wafer types. They open and close automatically by air flow thrust, preventing air backflow in ducts and avoiding air cross-contamination in the system and equipment reverse rotation, and are mostly used at fan outlets, exhaust shafts and other positions.

Airtight valves have high air tightness; their blades and valve frames adopt rubber sealing structures to achieve complete shut-off of air ducts, applicable to scenarios with high sealing requirements such as civil air defense projects and clean rooms. Some are electrically controlled for accurate opening and closing. In addition, there are three-way regulating valves, used for air flow reversing and volume distribution at air duct branches to realize precise regulation of one air inlet splitting into two air outlets.

Most of these ventilation valves are made of cold-rolled steel plates or stainless steel plates. Electric types are equipped with actuators, enabling manual/ automatic linkage and adaptation to intelligent control systems. Selection shall be determined according to system functions, air duct pressure, medium temperature and fire protection requirements. The accuracy of installation and commissioning directly affects the operating efficiency and safety performance of the ventilation system.