Chromalox Tubular Seal Meets Challenging Third-Party Demands

Chromalox catalog tubular lp


The Problem

Changes were made to the UL 197 9th Edition titled, Commercial Electric Cooking Appliances. These changes required the manufacturer to confirm that the electric sheathed heating elements used as components in their equipment met the Conditions Of Acceptability specified for that component in its UL file. For electric sheathed heating elements, this meant that the material used as a end seal on the element had to be operating within its temperature specification limit in the OEMs equipment.

This particular manufacturer used electric sheathed heating elements in food warmers, toasters, and heated cabinet drawers, which fall under the domain of the UL 197 standard. As this company is an industry leader, they took a proactive approach and started to assess their product requirements immediately. Not only did they have to meet the new UL standard, they also served a global export market where their products were required to meet stringent import inspection standards for leakage current and resistance values. This was compounded by the fact that ocean transport is an extremely humid environment, and these elements can be in transit for weeks at a time where the environmental conditions can be relentless for the duration of shipment. During this period, water vapor pressure drive from humidity can compromise heater resistance values by moisture absorption into the electrical heating elements insulation material. This results in elements having higher than desired leakage current values, and the possibility of being refused upon inspection at the point of entry into the other country.

Given these challenges, it was the goal of the manufacturer to exceed both the domestic UL and international import inspection requirements with the use of a single end seal specification that would accommodate both. Working with Chromalox they specified V-Seal for this requirement. The patented seal prevents moisture ingress into a tubular element, and meets the strict UL 197 standards. 

The Advantages
The V-Seal enabled this food equipment manufacturer to satisfy global markets, and protect its position as the industry leader in offering this technology.  

  • Tubular element parts have a longer shelf-life, and are not damaged in high moisture storage areas. 
  • End-product meet or exceed UL 197 requirements
  • Elements pass import inspections