Suggested Watt Densities for Electric Heating Elements

Always consider proper watt density
for your electric heater application.

Reprinted with permission from Hotwatt

The rates below are recommended watt densities for use with various materials. Safe values vary with operating temperature, flow velocity, and heat transfer rates. In general, the higher the material temperature, the lower the watt density should be, especially those materials which coke or carbonize, such as oils. Watt densities should be low if a material is being heated to a temperature near where the change of state to a vapor occurs (water to steam @ 212°F) since the vapor state has much poorer heat transfer capabilities.

Material being heated	Maximum Operating Temp.°F	Maximum Watts Per Sq. In.*
Acid Solutions:    Acetic    Chromic (5%)    Citric Ferric    Chloride (40%) Hydrochloric Nitric (50%) Sulphuric	212 Boiling Boiling Boiling 150 Boiling Boiling	40 40 40 40 30 40 30
Alkali & selected oakite cleaning solution	212	40
Asphalt binder, tar, other viscous compounds	200 300 400 500	8 7 6 5
Caustic Soda 2%                     10%                     75%	210 210 180	45 25 25
Coffee (Direct Immersion)	Boiling	90
Dowtherm A®    flowing at    1 ft/sec or more    Non-flowing	750 750	22 10
Ethylene glycol	300	30
±Fuel Oils    Grades 1 & 2 (Distillate)    Grades 4 & 5 (Residual)    Grade 6 & Bunker C    (Residual)	200 200 160	22 13 8
Gasoline, kerosene	300	20
Glue (heating indirectly using water bath Lead-Stereotype pot)	600	35 on casting
Liquid ammonia plating baths	50	25
** Lubrication Oils    SAE 10, @ 130°F    SAE 20, @ 130°F    SAE 30, @ 130°F    SAE 40, @ 210°F    SAE 50, @ 210°F	250 250 250 250 250	22 22 22 13 13

* * Some oils contain additives that will boil or carbonize at low watt densities. Where oils of this type are encountered, a watt density test should be made to determine a satisfactory watt density.

Material being heated	Maximum Operating Temp.°F	Maximum Watts Per Sq. In.*
Metal melting pot	500 to 900	20-27
Mineral oil	200 400	20 16
Molasses	100	2-3
Molten salt bath	800-950	40
Molten tin	600	20
Oil draw bath	600 400	20 24
Paraffin or wax	150	16
Photographic solutions	150	70
Plating solutions:    Cadmium plating    Chrome plating    Copper plating    Nickel plating    Tin plating    Zinc plating		40 40 40 40 40 40
Salt Bath	900	30
Sea Water	Boiling	90
Sodium cyanide	140	40
Steel tubing cast into aluminum	500 to 750	50
Steel tubing cast into iron	750 to 1000	55
Heat transfer oils    flowing at 1 ft/sec or more	500 600 650 750	22 22 22 15
Trichloretylene	150	20
Vapor degreasing solutions	275	20
Vegetable oil (fry kettle)	400	30
Water (process)	212	60
Water (washroom)	140	80-90

* Maximum watt densities are based on heated length, and may vary depending upon concentration of some solutions. Watt density should be kept as low as possible in corrosive applications since higher watt densities accelerate corrosive attack on element sheaths. Consult BCE for limitations.

Important: The above values are estimates. It is strongly suggested that you discuss your requirement with an application expert before you apply any electric heating element in to a process where the proper watt density is unknown.

Attending MD&M West and the Value of Exhibitions

Visit BCE at booth 2184

This week BCE is exhibiting at MD&M West (Medical Design and Manufacturing West) in Anaheim, CA. While the title implies medical equipment design, the exhibition also includes packaging equipment and other related equipment. The show runs Feb. 9, 10 and 11.

MD&M is the world's largest medical design and manufacturing exhibition. It "offers three days of technical presentations, hands-on design workshops, demonstrations and ticks and tricks to help you stay ahead of the game in 2016."

Representatives from many well-know "Medtech" companies will attend and a full 3 days of presentations are planned. Some of the more interesting titles are "The Creative Keys: How to Turn a Thought Into a Thing with Ease and Grace", "New Product Development Technologies and NexGen Applications", and "Leading the Smart Manufacturing Revolution".

BCE's Applied Resistance Group will showcase its thermal system design capabilities, advanced ceramics machining, laser machining, and thick film circuits and heaters. BCE is quickly developing a nation-wide reputation as an excellent partner for these products.

BCE is exhibiting their
years of experience in
thermal system design,
thick film, laser machining,
and advanced ceramics.

BCE has decades of hands-on experience with thermal systems and advanced ceramics. The result is a strong expertise in analytical instrumentation, semiconductor equipment, photovoltaic devices, medical equipment, plastics processing machinery, foodservice equipment, packaging machinery, aerospace technologies, and laboratory R&D.

Exhibitions and trade shows are great places to network and build business relationships. Face-to-face contact with prospective customers and vendors provide an opportunity for strong business relationship foundations. Meeting with someone in person is far better than meeting online.

One huge benefit of attending an exhibition is the ability to meet large numbers of helpful people in one place. When attending an exhibition, it's best to plan ahead and utilize your time efficiently. Set up appointments in advance so that you don't waste time wondering. Make a list of booths and people you really want to get to know. And please, stop by the BCE booth (2184) - you'll be glad you did.

Engineered Thick Film Heating Elements

Thick film heating elements were developed as an outcropping of long-time technology used for production of printed circuit boards and hybrid circuitry. The term “thick film” refers to the resistance circuit (or heating element) that is deposited by a screen printing process, typically 0.0005” thick and deposited on a ceramic or metal substrate.

A thick film heating element provides precise layout of the resistance element exactly where the heat is required. Additionally, intimate contact of the heating element to the substrate is guaranteed delivering maximum heat transfer by eliminating any air gap there between between the heating element and the substrate.

Thick film heaters give engineers broad design flexibility of the heating circuit itself. Designers can precisely distribute heat where its required and also dictate the uniformity in temperature distribution. This design flexibility can be applied to curved and irregular shapes, as well as flat, to accommodate custom heating applications.

Highly machined ceramic parts, with intricate designs, high dielectric properties,  and smooth surfaces are ideal for thick film heating elements. Advanced ceramic's chemically inert, non-porous properties facilitates the careful and exact control of the trace pattern and trace dimensions, thus providing a “heated part” approach to equipment design.

Features of Ceramic Thick Film Heaters:

• High dielectric
• High thermal efficiency
• Very rapid heating
• Uniformity of heated area / pattern
• High watt densities
• Chemically inert
• Custom shapes and sizes
• Custom wattages and voltages
• Embedded temperature sensors

Thick film heating elements are used in many industries today, particularly in advanced technologies such as analytical instruments, medical equipment, aerospace, semiconductor, and research & development.

BCE, located in the San Francisco Bay Area, has decades of experience in consulting, designing, and applying thick film heaters. Their reputation has grown nationally as a premier custom thermal solutions provider.  For more information, contact:

BCE
21060 Corsair Blvd
Hayward, CA 94545
Phone: (510) 274-1990
Fax: (510) 274-1999
E-mail: sales@belilove.com

www.belilove.com

Engineered Ceramics for the Analytical, Semiconductor, Electronics, Defense, Medical, and Aerospace Industries

Advanced ceramics machining

Ceramics are inorganic, non-metallic materials made from compounds of a metal and a non-metal. They include such compounds as oxides, nitrides, and carbides. Ceramics are typically insulators (electrically and thermally), but their properties can vary widely - for instance some ceramics actually belong to the super-conductor class. Advanced ceramics, such as alumina, zirconia, silicone carbide and silicone nitride are very resistant to corrosive chemicals and high temperatures. They posses higher stiffness and lower fracture toughness than metals.

Ceramics behavior under mechanical, thermal and chemical stress differs widely from other materials such as metals, which makes machining ceramics very difficult and requires knowledge, experience, equipment, and expertise. As the need for higher performance / higher precision parts has increased, advances in ceramics machining has overcome many of yesterdays machining challenges, and today's high-tech processes are yielding extremely close tolerance parts and ultra precise shapes.

Ceramic machining is the process of shaping the advanced ceramic material into high precision parts used in industry. Machining removes unwanted material by mechanical means, using very hard abrasive particles. If the machining is done before sintering (to achieve a "near-net-shape" to save time and money), the ceramic is referred to as in the "green state". Green state machining offers considerable advantages in quality, lower production costs, and manufacturing flexibility.

Grinding, the material removal process where abrasives is used, is the most prevalent machining process for advanced ceramics. Polycrystalline diamond and cubic boron nitride are the grinding materials of choice because of their hardness. Their particles are fixed to a grinding tool (or wheel) via resin or vitreous bonding, and are turned against the ceramic part at high speeds. Variation in grinding efficiency is a challenge though, due to the constant changing state of the grinding tools because of wear and abrasion.

The following chart is a helpful reference guide to the properties of some common advanced ceramics (click on chart for larger view).

For any inquiry on precision machined ceramics or thick film ceramic heaters, contact BCE at:

21060 Corsair Blvd
Hayward, CA 94545
Phone: (510) 274-1990
Fax: (510) 274-1999
www.belilove.com
E-mail: sales@belilove.com

Happy New Year from BCE

Everyone at BCE (Belilove) would like to wish all of our customers, vendors, suppliers, families and friends a very happy, healthy and prosperous 2016!

We look forward to serving our customers and working alongside our partners and employees for our mutual success and growth.

Cheers!
The BCE Team

Electric Heating Elements in Life Science and Analytical Instruments

Life science and analytical instrumentation are designed to determine the identity and structure of inorganic and organic liquids and gases, and then detect, separate and analyze their individual compounds.

These processes require the application of heat to the sample. Very specialized heating elements are normally required to achieve the temperatures (300 deg. C to 500 deg. C) to achieve breakdown of the samples into base components. Since sample sizes are normally very small, the heating elements must also be small, react quickly, and be easy to control.

Typical applications for these heaters are mass spectrometers (MS), high performance liquid chromatographs (HPLC), other gas chromatography (GC), flow instrumentation, toxic gas analyzers, and laboratory culture instruments.

BCE is a leading designer and fabricator of high performance, highly accurate, fast responding heating elements for life science and analytical instruments.

Intrinsic Safety for Hazardous Areas Explained

Intrinsic Safety Barriers are devices that limit power delivered from a safe area into a hazardous area. The possibility of an explosion is prevented, not merely contained (by a housing or a conduit). The total energy is maintained within safe limits, not electrical energy (voltage and current), eliminating an ignition from excessive heat. The use of an intrinsically safe design offer many cost and safety advantages.

• Easy access to components - no time spent opening/closing explosion proof enclosures.
• Safety assured due to low voltage system.
• Use of standard wiring, cable runs, and light gauge cable.
• Calibration and maintenance the same as if in a general purpose area.
• No special hazardous area procedures for opening enclosures, area gas testing, or shut-down process.
• Simple use of plug-in modules.

The document below provides an excellent explanation into Intrinsic Safety and goes far more in to the background, concepts, principles, and devices used in this approach to safety in hazardous areas.

Intrinsic Safety Explained from Belilove Company-Engineers

For more information, contact:

BCE

P.O. Box 55936
21060 Corsair Blvd
Hayward, CA 94545

www.belilove.com
Phone: (510) 274-1990
Fax: (510) 274-1999
E-mail: sales@belilove.com