Silicone Rubber Heater Makes Microfilm Imaging Possible In Wide Ambient Temperature Range


A manufacturer of table-top microimagers was in the midst of final testing prior to release for manufacture when they discovered the florescent lamps used for imaging would not produce the amount of light necessary for optimal results when operated below 65°F (18°C).

The pressure was on to improve the current design and make product introduction time tables. A call was made to Watlow where a brief discussion of the problem resulted in the Watlow Sales Engineer securing some appropriate size and power flexible heaters from stock for the customer to experiment with. These were affixed to the aluminum tubes that surrounded the florescent lamps and provided the aperture opening.


After exact wattage requirements were determined, temperature control was addressed. The solution was to wire the heaters in series so that a single, internal thermostat and thermal fuse would power both heaters when ambient dropped below 70°F (21°C); and protect the system from overheating.

With production held up, the solution was turned from design into a production order within six weeks; with Watlow affixing the heaters to the aluminum aperture tubes and supplying a complete sub-assembly.

Additionally, Watlow's pioneering efforts in securing UL® and CSA approvals for silicone rubber flexible heaters met requirements for agency approval.

Continual product improvement resulted in using a creep-action thermostat for quieter operation, indexed connectors to avoid incorrect electrical connection and securing a new aluminum tube supplier to yield better vulcanizing and anodizing. By taking full responsibility for securing and assembling the heated aperture tubes, Watlow could conduct a ground check and stamp the assembly CSA approved. Finally, customer Class A Certification permitted Watlow to manufacture and ship-to-stock for final assembly.