Automatic Air Vents for Liquid Processes (SA3, VC, VS1C Series) Get a QuotePrintable PDF Overview Continuously discharge air and gas that build up inside water supply pipes Automatic air vents feature a relatively small orifice and are suitable for discharging air and other gases during normal operation. By installing them in places where air tends to accumulate, it is possible to prevent issues caused by air trapped in water supply pipes. Air vents can also help to prevent a vacuum from forming in pipes. When the main valve is open and pressure inside the pipes falls below the pressure of the surrounding atmosphere, air will enter the valve, preventing vacuum conditions from forming and allowing liquid to be easily passed downstream. Due to the relatively smaller discharge capacity of automatic air vents, in cases where it is necessary to discharge large amounts of air/gas rapidly upon startup, it is best to use these products in combination with a dedicated rapid initial air vent. Rapid Initial Air Vents for Liquid Processes (VAS & VA Series) Features Automatic Air Vents (all series) Simple construction with no levers or hinges Only one moving part: the Free Float®. This eliminates concentrated wear and provides long service life. Can function as a vacuum breaker by allowing air to flow in when a vacuum forms Provides a tight, reliable seal VC Series Precision-ground float, rubber valve seat VS1C Series High precision-ground float, 3-point seating Can be used with liquids with specific gravities as low as 0.8 SA3 Series Light-weight, compact Auxiliary valve seat enables maintenance during operation Provides a tight seal, even at pressures as low as 0.01 MPa Applications Automatic air vents are suitable for: processes which require the continuous discharge of air/gas under normal operation conditions water supply pipes, cooling & heating equipment (SA3, VC) use in small and narrow installation spaces (SA3) fan coils, radiators, and other air conditioning equipment (SA3) suitable for non-water liquid processes (VSC1, non-flammable and non-corrosive liquids only) * When rapid discharge of large quantities of air is required upon startup, please use together with a rapid initial air vent. Rapid Initial Air Vents for Liquid Processes (VAS & VA Series) Utilization Examples Lineup Applications Type of vent required Rapid initial air vent Automatic air vent Water supply pipes, water tanks, etc. ● ● Fan coils, radiators, etc. - ● Water pumps etc. ● - Purpose of use Compatible fluid Operation pressure (mpag) Max. discharge capacity (l/min) Body material Model Product photo Product specifications Initial air venting + automatic air venting during operation Water, hot water 0.01-0.3 5.4 Forged brass SA3-3 No Data Sheet 0.1-1.0 9.2 SA3-10 0.05-0.5 25 Cast bronze VC2 81 kb 0.1-0.6 90 Cast iron VC3 0.1-1.0 380 VC4 Water & other liquids (non-corrosive, non-flammable) 0.01-1.0 170 Cast stainless steel VS1C-10 271 kb 0.01-2.1 130 VS1C-21 Operation Animation VS1C When liquid is pumped through the system at startup, the initial air inside the piping is pushed into the air vent by the pressure of the flow. The float remains in the lower part of the air vent, allowing the valve to remain open and continuously discharge air. After the initial air venting, liquid flows into the air vent. The float rises with the rising liquid and closes the valve. If air enters the air vent while it is closed, the liquid level drops and the float lowers, allowing the valve to open and discharge air once more. Free Float® & 3-point Seating Free Float® These products contains no levers, hinges, or other delicate components which typically cause valves to malfunction. As the float is the only moving part, wear and malfunctions are minimized. The float surface provides a nearly infinite number of valve faces to close against the seat, allowing the valve to excel in durability. 3-point Seating 3-point seating supports the high-precision ground float at 3 separate points when the valve is closed, allowing for an extra tight seal. (VS1C only)
