The multi-functional air valve is a protective device used in water supply pipelines. Its primary function is to prevent water hammer (the impact caused by sudden pressure changes) through exhausting and inhaling. The core function is to exhaust and inhale, automatically exhausting when the pipeline pressure drops to balance the internal and external air pressure; when the pressure rises, it closes the exhaust port to prevent liquid backflow. It also takes into account water hammer protection by delaying the exhaust time to form an elastic compression space, thus suppressing the sudden pressure rise during water column reunion. The main working principle of Zhejiang Shanliu's water hammer proof air valve is under low pressure conditions: when the pipeline pressure drops, the valve automatically opens the exhaust port to exhaust accumulated air, avoiding negative pressure that can cause water column separation; under high pressure conditions: when the pressure rises, the valve closes the exhaust port to prevent gas or liquid backflow, maintaining system stability. The structure is simple, requiring no complex accessories, with flexible installation and low cost. It is widely used in municipal water supply, wastewater treatment, industrial fluid transportation, cooling water systems, and other applications requiring water hammer protection.

An exhaust valve is a device used to eliminate gas from pipelines, widely applied in various pipeline systems such as tap water transmission pipelines in urban water plants, independent heating systems, central heating systems, heating boilers, central air conditioning, floor heating, and solar heating. The primary working principle and function of the exhaust valve produced by Zhejiang Shanliu is to prevent gas accumulation in pipelines, enhance pipeline efficiency, and reduce energy consumption. There are various types of exhaust valves, primarily including: single-port exhaust valves for exhausting gas in independent heating systems, central heating systems, heating boilers, central air conditioning systems, floor heating systems, and solar heating systems; double-port exhaust valves suitable for pipelines with water as the medium, serving as a device to eliminate gas from pipelines, thereby enhancing the efficiency of water conveyance equipment and protecting pipelines from deformation and rupture; quick exhaust valves, the most advanced cylinder-type exhaust valves in China, capable of continuously and rapidly exhausting gas from pipelines, applicable to various pipeline environments; and composite exhaust valves suitable for complex pipeline systems requiring the removal of large amounts of gas.

A breathing valve is a specialized safety accessory used for storage tanks (such as those for petroleum, chemical, food and other liquid storage tanks). Its core function is to automatically regulate the internal pressure of the tank, preventing deformation or damage caused by overpressure or vacuum. When the pressure inside the tank rises beyond the set value due to factors such as temperature changes or filling and unloading operations, the breathing valve automatically opens to release pressure (exhale). When the pressure drops to the negative set value, it automatically opens to inhale and replenish pressure, thereby maintaining the tank pressure within a safe range. At the same time, the breathing valve effectively reduces product evaporation loss and minimizes atmospheric pollution. Common types produced by Zhejiang Shanliu Valve Technology Co., Ltd. include all-weather breathing valves, explosion-proof flame arrester breathing valves, and recovery type with connection pipes. Materials can be selected from aluminum alloy, stainless steel, carbon steel, etc. These valves are widely used in petrochemicals, oil depots, chemical industries, and environmental protection fields.