The KITO VS/KS-…-IIB3, type D11N, is a self-actuated vacuum relief valve designed for air intake on storage tanks, vessels, and pipelines. Its function is to prevent unacceptable vacuum conditions and incorporates an integrated flame arrester element for protection against flame transmission.
Suitable for installations handling flammable liquids of explosion group IIB3, with MESG ≥ 0.65 mm and maximum operating temperature 60°C. Typical applications include chemical, fuel, solvent, and volatile product tanks where vapor evacuation, cooling, or contraction may generate vacuum conditions.
Available in sizes DN 50 to DN 400. Standard flanged connections per EN 1092-1 type A: PN 16 for DN 50–150, PN 10 for DN 200–400. ASME B16.5 Class 150 RF option available. Set pressure range depends on size and configuration, typically 1.8 to 200 mbar.
Standard construction: carbon steel body/cover, with stainless steel 1.4571 option. Valve seat and spindle in stainless steel 1.4571. Standard seal is NBR; alternatives include Viton, PTFE, EPDM, or metal-to-metal. For setpoints ≥100 mbar, PTFE or metal sealing is recommended. Flame arrester element is replaceable.
Valve sizing should consider:
Flow curves are based on air at 1.29 kg/m³ density and 40% accumulation above valve setpoint, per DIN 4119.
Is an actuator required?
No. Operation is mechanical, based on differential pressure.
When is stainless steel construction recommended?
For corrosive environments, marine atmospheres, or media incompatible with carbon steel.
Which points are checked during maintenance?
Seat, disc, sealing elements, free movement of mechanism, and cleanliness of flame arrester element.
KITO® VS/KS-…-IIB3
