RS PRO 6871 Series Momentary Air Switch, 250mm Fly Lead, Surface Mounted

Introducing the series of excellent quality Air Switches from RS PRO. Air switches are a type of push button switch that uses air pressure instead of electricity to activate the device it is connected to. This series of single-pole momentary or latching air-operated switches are suitable for use with all air actuators and accessories.

Air Switches are available in two mounting options:

• Surface mounting with side connection of the air tube: 319-714 & 319-708
• Through panel fixing with the air tube connection via the base: 319-720 & 319-736

The Surface Mounting type is ideal where it is required to seal all electrical connections from the environment in an enclosure. Through panel, fixing is by means of a 9/16 UNF nut (supplied) or may be surface mounted using the additional 3.2mm dia fixing holes, suitable for M3 or No. 6 self-tapping screws. SPDT microswitch contacts are rated at 16A 250 Vac/30Vdc and connection is via 250 ( 1/4 in) terminals. Operating temperature range -10°C to +60°C (subject to tube length limitations - see additional data tables below)

• The single pole changeover switch
• Electrical rating 16A 250V AC
• Back entry 4mm spout
• Use with 3mm I/D tubing
• Approx. 1PSI of operating pressure

The air switch works in a similar way to electrical switch but instead of electricity, it uses air pressure. When the air switch button is pressed it triggers a pulse of air towards the power control unit. The air goes through tubing connected between the button and the control unit. Once the control unit receives the "air signal", it turns on the power. To turn off, the button needs to be pressed again.

They are usually used for:

• Safe actuation of electrical devices in hazardous environments or in close proximity to water
• Actuation of sensitive electrical circuits

CSA

Actuators, Switch Elements, Tubing & Accessories

The air operated switch system offers enhanced safety in hazardous areas by allowing remote operation of electrical circuits.
The actuator is a bellows which, when compressed moves air down the air tubing to the switch element. This compressed air then expands a bellows in the switch, which operates the electrical contacts.
When used in wet environments or where electrical switching would be dangerous due to arcing, the switch and all electrical wiring can be located outside the hazardous area giving the operator total electrical isolation for the equipment.
Such applications include: Battery charging rooms, laboratories, garages, or wherever explosive gases, vapours or powders may exist.

When assembled the air switch and actuator form a sealed system, therefore temperature variation will cause pressure changes, which can in extreme cases affect the performance of the switch. To prevent this the total volume of the system must be kept below a critical value for a given temperature range and, to this end, a maximum length of air tubing (and hence volume) can be given for any combination of switch and actuator.
The additional data tables give these lengths in metres; for moderate and extreme temperatures.