AIA: Seals Create Safe Environment for Electronics
Daisy Data Inc. (New Haven, PA) specializes in manufacturing electronics equipment enclosures and purging controls for use in hazardous areas like those found in the food processing and pharmaceutical manufacturing industries.
The basic function of the enclosures is to keep electronics that have the potential of producing sparks or high temperatures isolated from explosive environments. This is done by placing the equipment-often a computer or monitor-in a sealed stainless steel enclosure. The enclosure is then protected by a microprocessor-controlled purge system that replaces the enclosure atmosphere with inert gas under slight pressure. The enclosure system includes viewing windows, internal fans and alarm contacts.
To ensure that the enclosures are airtight, Daisy Data assembles them using sealing boots for each enclosure's purge device switches and self-sealing fasteners from APM Hexseal Corp. (Englewood, NJ).
The switch sealing boots are single-piece and manufactured from silicone. A panel sealing rib encircles the mounting hole and a second inner seal encompasses the toggle itself in the event of damage to the end of the boot. The boot incorporates a molded-in mounting nut that allows easy and secure attachment.
As fasteners, Daisy Data uses Seelskrew bolts, which incorporate an O-ring in a sealed groove in the head. The bolts are reusable and the O-rings provide both vibration resistance and a seal against liquids, gases and dust under pressures of up to 6,000 psi. The O-rings are also silicone, making them chemically and thermally resistant over temperatures ranging from -160 to 500 F.
According to Daisy Data engineering manager Ray Ravida, the company uses the fasteners throughout its product lines, with around a dozen screws per enclosure. He says the fasteners are ideal since the O-rings seal against both the internal pressure of the inert gas system as well as external gasses and contaminants.
"They are also easy to install," he says, noting that the Seelskrew bolts are similar to and interchangeable with conventional fasteners.
For more on self-sealing fasteners and switch boots, call 201-569-5700, visit www.apmhexseal.com or eInquiry 6.
For more on equipment enclosures, call 717-932-9999, visit www.daisydata.com or eInquiry 7.