Electric Heating Co., Inc

The Tip

We have had a number of instances where distributor salespeople want to specify the hot tip for the Watt-Flex® cartridge heaters and one or more factors cause us to reconsider. As a quick review, when we bend our heater over on itself, we have the option of leaving the coil compressed so that it passes right across the tip of the heater, producing a fully heated tip or stretching the coil so it de-rates the tip wattage.

The fully heated tip is exclusive to our split sheath design and should only be used when the heat can be drawn off the tip of the heater through contact with the end of a closed bore. This is particularly necessary if the watt density is high,because the tip will generate substantial heat with no ability to lose it. That will cause the resistance coil to work harden and become brittle, eventually becoming unable to carry the electrical load. The only other instance of effective use of the hot tip is the continual presence of air flow, sufficient to wipe the heat away from the heater. The hot tip is ideal for use in branding tools, heat stake machinery, punch sealing machines, hot air knives and gate probes for injection molding.

The cool tip design produces heat to the end of the heater, but essentially takes heat off the "crown" of the tip. If you look into an open bore, it will appear that the heater has a hot tip as the capillary heat will move down the sheath to the tip. The fear is that, if the heat cannot be pulled off a hot tip, it will decrease the ability of the MgO insulation to act as a dielectric and a short to sheath will occur.

Therefore, a heater to be used in an open bore should be designed as a cool tip. Any hole that is drilled through a laminating press, heat seal platen, packaging sealing bar, extrusion head, plastic or rubber mold or manifold, thermoforming die and screen changer will employ a cool tip.

Friday Funnies

Actual Doctor's Stories

1. A man came into the ER and yelled, "My wife's going to have her baby in the cab!" I grabbed my stuff, rushed out to the cab, lifted the lady's dress, and began to take off her underwear. Suddenly, I noticed that there were several cabs -- and I was in the wrong one.

Submitted by Dr. Mark MacDonald, San Antonio , TX .

2. At the beginning of my shift, I placed a stethoscope on an elderly and slightly deaf female patient's anterior chest wall. "Big breaths," I instructed.

Submitted by Dr. Richard Byrnes, Seattle , WA.

Dalton Electric Heating Co., Inc (978)356-9844
28 Hayward Street Ipswich, MA 01938 USA

(C) Copyright 2006 - 2008. Dalton Electric Heating Co, Inc. All Rights Reserved.