AFS-G1 Hygrostat

Brand: KOBOLD Instruments, Inc.

The KOBOLD Hygrostat AFS-G1 serves as a two-position controller to regulate relative humidity indoors or in air ducts. The moisture sensing element in the sensor comprises several strips of plastic fabric each with 90 fibers of 3 µm diameter.

These plastic fibers undergo a special process to acquire hygroscopic properties, this means that they absorb and release moisture. The molecular structure of the fibers changes when they absorb water, giving rise to a measurable change in length.

The length of the plastic fibers is thus a measure of the relative humidity. The swelling effect, acting primarily in longitudinal direction, is transferred over a suitable lever system to a microswitch with an extremely small changeover movement.

The measuring element reacts quickly and accurately to the change in humidity. The setpoint is set with the setpoint button so that the microswitch is actuated by the lever system when the humidity setpoint is reached.

The special treatment of the measuring element ensures that its hygroscopic properties remain stable, that is sensitivity is maintained until destroyed by external influence.

Regeneration found in conventional instruments is not required, but is also not damaging. The harp-shaped measuring element is protected by a perforated probe tube and is open to the housing. The hygrostats are designed for unpressurized systems.

Specifications

Accuracy

  • ± 3.5 % Relative Humidity: > 50 % Relative Humidity - Measuring Accuracy
  • ± 4 % Relative Humidity: < 50 % Relative Humidity - Measuring Accuracy

Ambient Temperature Range

  • -30° to 60° C (-22° to 140° F)

Applications

  • Air Ducts in Air Conditioning Systems
  • Air Conditioning Cabinets
  • Building Management Systems
  • Film Industry
  • Glasshouses for Horticultural Businesses
  • Grain Dryers
  • Hospitals
  • Paper Industry & Printing Trade
  • Refrigerated Rooms for Fruit & Vegetables
  • Textile Industry
  • Warehousing of Foodstuffs & Semi-luxury Foods & Tobacco

Cable Entry

  • Cable Gland Pg 13.5 - Cable Connection

Differential Pressure

  • 3 to 6 % Relative Humidity - Approximately Differential Gap (Microswitch)

Electrical Connectors

  • Conductor Cross-sections to 1.5 mm - Connection Terminals

Electrical Contacts

  • Silver - Contact Material

Electrical Rating

  • 100 mA - Minimum Contact Rating
  • 125 Vac - Minimum Contact Rating

Enclosure, Body Material

  • ABS (Acrylnitril-Butadien-Styrol)

Environmental Protection

  • IP54

Humidity

  • 30 to 100 % Relative Humidity - Measuring Range (Full Scale Range)
  • 35 to 100 % Relative Humidity - Setting Range (Operating Range)

Media

  • Air
  • Pressureless, Non-Aggressive

Mounting

  • Duct Mounting - Bore Holes in Housing Base
  • Surface Mounting - Bracket (Optional)

Mounting Position

  • Horizontal
  • Vertical - Sensor Vertical Pointing Down

Operating Temperature

  • 0° to 60° C (32° to 140° F)

Output

  • 15 A - Resistive Load
  • 2 A - Inductive Load (Cos φ = 0.7)
  • 230 Vac - Resistive Load & Inductive Load (Cos φ = 0.7)

RFI/EMI Protection

  • EN 50081-2 - Emitted Interference
  • EN 50082-2 - Noise Immunity

Sensor / Probe Material

  • Stainless Steel

Supply Voltage

  • 250 Vac - Maximum

Temperature Effect

  • -0.2 % Relative Humidity/K (At 20° C & 50 % Relative Humidity) - Average Temperature Coefficient

Documentation

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