An instructional blog about specialized electric heating elements and vacuum feedthroughs for the OEM, analytical, semiconductor, aerospace, pharmaceutical, chemical, water, environmental, food processing, and alternative energy markets. Please feel free to contact us at (510) 274-1990 with any questions. BCEmfg.com
Here is a very handy "cheat-sheet" for calculating Ohm's Law and other engineering constants that come in very handy when calculating wattages, voltages and current draw of electric heating elements.
A cartridge heater is a cylindrical electric heating element constructed by tightly winding nichrome wire around a ceramic bobbin, and inserting the wound bobbin into a metallic tube (sheath). The tube is then backfilled with magnesium oxide (MgO) powder to electrically insulate the nichrome wire from the sheath. The heater diameter is then reduced (swaged) to compact the magnesium oxide for better dielectric, while at the same time improving thermal conductivity.
Cartridge heaters come in many diameters and lengths. They vary in voltages, wattages and watt densities. Sheath materials are typically Stainless Steel of Incoloy 800. The electrical leads terminate from one end of the heater and vary in length and insulation material, depending on application and operating temperatures.
Most cartridge heaters are used in some form of die or platen heating. A close tolerance hole is drilled into a metal block, and the proper diameter heater is then inserted in to the hole. It is best to make sure the diameter of the heater is just a few thousands of an inch less than that of the hole, so that maximum surface contact, thus thermal conductivity, can be achieved. A loose fit will cause the internal temperatures of the cartridge heater to climb and the heater will fail prematurely.
Common die heating, or platen heating, applications are:
Injection mold platen heating
Heating medical equipment components
Compressor sump heating
Bolt heating
Extruders
Packaging equipment
Sealing equipment
Analytical equipment
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OEMs often need custom designed heating elements for their equipment. Designing an electric heating element, or a complete thermal system, requires both electrical and mechanical engineering skills. Often, you can save time and money by calling in an expert with the proper experience to assist.
Belilove Company-Engineers has decades of experience developing custom thermal solutions in many industries - from low tech to cutting-edge high tech, from foodservice appliances to semiconductor processing equipment, Belilove has "been there, done that". So the next time you need an electric heating element, temperature sensor, or controller, Think Belilove.
Annunciators are found in industrial control rooms, boiler rooms, power substations and just about any type of process control operations room where the process conditions need to be closely monitored and where constant status indication is important.
Here is an outline for the primary selection criteria for an integrated logic alarm annunciator:
Chassis
Panel mount
Surface mount
Rack mount
Alarm Points
How many alarm points do you have? Annunciators break down alarm points by "cell" and you call out the number of cells based on the layout desired. For instance, a 1x4 would be 1 annunciator cell tall by 4 cells wide.
Pushbuttons (and Location)
Occupying bottom right
module cell space
On the bottom right trim of the chassis
Located remotely
The Available Panel, Box or Cabinet Space Available
Dictates how alarm points and pushbuttons are arranged.
Networkable or Stand-alone?
Configuration via software?
Event recording?
Do you need electrical outputs?
Audible and visual signals: horn, beacon, bell
Common Trouble Alarm (CTA) Relay: notification of any alarm within the system (commonly used
for remote beacon or dial-up)
Group CTA functions: for critical and noncritical groups
Auxiliary Contact Repeat Relay: individual repeater output per input
High-temperature refractory metallization is the only solution for some packaging applications. Tungsten and Moly-Manganese metallizations have higher adhesion to the substrate than thick-film metallization. This makes it the ideal process for hermetic packages, brazed lead frames and packages requiring high operating temperatures. These metals can be screen printed, sprayed or hand-painted onto alumina oxide or beryllium oxide substrates. Patterns can be plated with gold and nickel or gold alone. Once gold plated, these surfaces are solder-able and wire bond-able with aluminum or gold wire.
Batch furnaces are ideal for accurate brazing of small quantities and large. Kovar, stainless steel, copper and copper/tungsten as well as many other metals can be brazed to metallized ceramic. When the application requires, step brazing can be performed to combine several sub-assemblies into the final product.
For more information on hi-temperature refractory metallization contact:
Thermocouple "Types", based upon standardized color designations is discussed, as well as thermocouple connectors, polarity and some aspects of construction (such as grounded vs. ungrounded vs. open tip).
Thermocouples are a fairly accurate, economic temperature sensor used in many industrial applications. They operate on the "Seebeck Effect" which is the phenomena of dissimilar metal conductors producing a measurable voltage difference between two substances.
Thermocouples are used widely in industrial thermal system design in industries such as power generation, primary metals, pulp and paper, petro-chemical, and OEM equipment.
For more information contact: Belilove Company Engineers
21060 Corsair Blvd
Hayward, CA 94545
Phone: (510) 274-1990
Fax: (510) 274-1999
E-mail: sales@belilove.com
Thick filmheating elements, originally designed for the automotive and military industries, are manufactured by depositing several layers of conductor, resistors and dielectric on to an insulator via a screen printing process. The dielectric is normally some type of glass or ceramic and provides electrical insulation for the screen printed heating tracks.
Thick film heating elements are almost always custom designed for OEM applications. They can be designed in all shapes and sizes, and have an ability to provide very high watt densities with excellent controllability. The largest markets for these heating elements are appliances, analytical instruments, automotive, semi-conductor, medical device, scientific and military equipment.
Because of their inherent low mass, and their ability to carry high watt densities, thick film heaters are very efficient and are an excellent choice where a rapid heat-up (response) is required.
