Aljac Electric Deadman Handswitch

Introduction

Intrinsically safe electric control of a pneumatically operated valve is now the most widely used method of controlling aircraft refuelling from either bowsers, hygrant dispensers, or fixed sytems. This method is also increasingly used to control tanker loading and offloading operations. Simply holding the handswitch allows the operation to commence and continue, while releasing the handswitch invokes the 'deadman' principle and will close down the operation, terminating flow. Because the handswitch is the point of control, it must be reliable, and yet sufficiently robust to survive the most ardulous operating conditions. A failure could have catastrophic consequences.

The Handswitch

Aljac Fuelling Components offers you a lightweight Polypropylene handswitch which is comfortable for the operator to hold for long periods, and yet robust enough to survive in the hostile operating enviroment.

The handswitch is based on a magnetic reed switch housed in a hermetically sealed glass phial which in turn is encapsulated inside an easily removable element. The body of the handswitch is fully sealed against water, fuel, dirt or dust ingress to IP67 standard and has an integral cable strain relief feature which works. The cable will not pull out of the switch if it fitted corectly. The reed switch is operated by a postively retained permanent magnet fitted to a Stainless Steel trigger, which is secured to the main switch body by a Stainless Steel pin. 

Cable termination is inside the body and uses a two way screwed terminal block, and we can supply the handswitch either with or without cable fitted. The free end of the cable can be terminated in your own junction box or with a weatherproof Niphan 2 pin Plug and Socket. A full range of operating spares is also available.

Specification

• Nett Weight: 250g (Deadman Handswitch only).
• Contacts: Normally Open, 15A rated.
• Switching Current: 0.5A max (AC or DC).
• Switching Voltage: 200V DC or 125V AC max.
• Switching element hermetically sealed and potted, so no approvals are required for use as an intrinsically safe switch.
• Cable Gland: To suit cable 5 - 10 mm diameter.

This switch is for use in intrinsically safe current limited circuitss only. If it is installed or tested in higher Voltage or Current applications the Reed Switch contacts will be welded toether and warrently claims will not be accepted.