Industrial and OEM Electric Heating Elements

Electric heating elements are used to provide localized heat for people, animals, and equipment. Because electricity is widely available, it's a logical source of energy for the creation of heat. Electricity is converted to heat by the resistance to electrical current flow by a conductor. This process is known as Joule heating or Ohmic heating. The transfer of heat from heating element to the workpiece needing to be heated is done through conduction, convection, or radiation. Electric heat is simple, clean, and efficient. Unlike other forms of energy to create heat, such as fossil fuel or nuclear sources, there are no concerns with flammable fuels, radioactive materials, or harmful by-products.

There are many places where electric heaters comes in touch with our lives each day. They are used to keep living spaces warm for human beings and animals (commonly referred to as "comfort heating"). Electric heating elements are found in common home appliances such as toasters, stoves, and hair dryers. But beyond the day-to-day consumer applications, electric heaters are also ubiquitous in industry. Industrial heating elements are critically important to many manufacturing processes, wether as an equipment component (OEM heaters), or directly used in the the processing of raw materials (industrial electric heaters).

In industry, electric heating elements are commonly used in the manufacture of electronics, semiconductors, medical devices, food equipment, plastics equipment, pharmaceuticals, glass, ceramics, primary metals, aerospace equipment, and HVAC equipment.   While the industries that use electric heaters vary widely, the application of electric heaters narrows to the heating of flowing fluids (which include gases and air) or the heating of a solid metallic, or non-metallic, workpiece.

Types of Electric Heaters Used in Industry and Original Equipment Manufacturing

While the modes of transferring heat from on body to another will always be conduction, convection, or radiation, the mechanical and physical properties of industrial heaters change dramatically, depending on the media being heated, the physical and limitations of the application, and the application's temperature requirements. The following are the most common types of industrial and OEM heating elements used.

Tubular Heating Elements

Tubular elements are a common form of electric heater. Essentially a metal tube with resistance wire and electrical insulation inside, tubular elements can be configured into almost uncountable shapes and sizes.

Cartridge Heating Elements

Cartridge heaters provide localized heat to restricted work areas requiring close thermal control. Dies, platens and a variety of other types of processing equipment are efficiently heated.

Flexible Heating Elements

Flexible Heaters are made from a variety of materials such as Silicone rubber, Kapton, Mylar, or Neoprene and have etched foil or wirewound resistance elements. Fast responding with excellent heating profiles, these heaters solve many tough equipment heating challenges. Custom shapes and terminations are designed to suit. Rapid prototype service available.

Ceramic Heating Elements

Composed of high temperature materials such as alumina ceramic substrates. The metal heating resistance element is thickfilm technology or wire.

Thick Film Heating Elements

A process of depositing a resistor “trace” of tungsten paste on top of a ceramic part in a process very similar to screen printing. The deposition process allows for close control of thickness and width of the resistor, thus accurately controlling the conductor resistance, wattage, watt density, and uniformity of the heated part.

Happy New Year!

Heated Cube for Next Generation Mass Spectrometry

BCE Heated Cube

BACKGROUND

An analytical company approached BCE for their small space and high temperature heated gas requirement.  They needed to reduce the length and diameter of the current heat source to be able to fit into a more compact design for their next generation mass spectrometry tool.

SCOPE

• The Heated Cube needed to satisfy the following:
• Temperature up to 500°C   
• Small, compact footprint 
• Insulate heat source to retain heat and reduce outer temperature 
• Reduce size from a 36” long cylinder to a 2” square cube 
• 120-Volt 200-Watt 
• Must pass all electrical safety and Meg-Ohm requirements 
• Air path must be clean and free from ni-chrome wire exposure (chromium flaking) 

OUTCOME

BCE produced a highly effective high temperature clean gas electric air heater with a major reduction in size.  A stainless steel gas heating package with a footprint of 2” x 1 ½”x 1” was the result.  This heater is compact and has an inlet of 1/8” BSPP and a 1/16” NPT outlet with a 36” long heated path that maximizes heat transfer to the fullest.

There are two zones of heat each at 100 watt with two sensors, one to control and one to monitor the temperature.  The outlet temperature can reach up to 500°C.

The Heated Cube comes complete with insulation and a SST jacket.  It can be mounted in an extremely tight space for most OEM tools that put a premium on space and performance.  Liquid and gas medium can be processed with this design.

Call BCE today at 510-274-1990 for more information, or visit their web site at https://bcemfg.com.

BCE Thanks Our Veterans

Veterans Day is a day of observance and celebration for those who have served in the United States military. Veterans Day was originally called Armistice Day because of the November 11 Armistice that ended World War I. In 1954 it was officially changed to Veterans Day to include Veterans of all wars. This holiday honors those who took an oath to defend the United States and our Constitution, from all enemies, foreign and domestic. Through the observance of Veterans Day, we remind ourselves of our Veterans patriotism, love of country and willingness to serve and sacrifice for the common good.

BCE thanks our Veterans, past and present, for serving our country and protecting our freedom.

Resistive Heating Elements for Gas Chromatography

Custom gas chromatograph heater by BCE.

What is Gas Chromatography?

The most basic understanding of gas chromatography (GC) is that of a separation technique. It is used in analytical chemistry for the prompt separation, identification and quantification of compounds that can be vaporized without decomposition. Common uses of GC include testing the purity of a substance or separating and identifying the different components of a mixture.

The basic components of the GC system are:

1. A long thin tube, referred to as a "column", and an oven or direct heating element that provides accurate temperature control and profiling. 
2. The injector, which provides the means for the sample to enter the column.
3. The detector, which provides the means for the sample to exit the column.
4. The temperature control system.

Basic Understanding of Gas Chromatography

The sample (analyte) is transported through the column by the flow of an inert, gaseous mobile phase (typically nitrogen, helium, argon, or carbon dioxide). The GC column contains a liquid referred to as the "stationary phase" which, as it traverses the column, is repeatedly adsorbed onto the surface of an inert solid and desorbed back into the carrier gas stream. Based on an adsorbent's composition, it can have varying affinities to "hold". Because some constituent components are likely to spend more time in the stationary phase, while others are likely to spend less time, the separation process occurs.

Constant demand for optimized analytical throughput, GC portability, and less costly analysis propels the development of new gas chromatography designs and technologies. In recent decades, resistive heating technologies designed for the sample column heating have become commercially available and have grown in popularity. Resistive heaters have clear advantages over traditional air bath ovens, most notably direct, low-mass heating through conduction. The growth of portable GC systems has also benefitted from small, compact, low power resistive heaters.

The temperature control system is at the heart of gas chromatography accuracy, sensitivity and speed. This system is comprised of the electric heating elements, temperature controllers, and temperature sensors. All are critical in sample and column temperature regulation.

Gas Chromatography Heaters

This specialized category of electric heating element is designed to provide extremely uniform temperature profiles across the length of the GC column. This uniformity accommodates a stable temperature environment for the capture of repeatable and consistent data between runs. Gas chromatograph heaters allow for very precise temperature ramping and set point control to very tight tolerances. This is critical because the slightest fluctuation in column temperature during analysis will have significant effect on analysis outcomes.

Controlling the Temperature of the GC Column

Once the temperature profile of the column is established, a precision thermal control system is required to provide precision temperature control during the operation of the profile. The control system must be highly accurate and responsive, and must include advance control algorithms to handle a wide variety of column profiles.

Temperature Programmed Elution

In most cases, a ramping temperature profile is required when the analyte enters the column. The ramping temperature profile starts at a lower temperature and increases over time in a precise and linear fashion. At different points along the temperature profile, compound movement changes according to temperature exposure. This precise exposure to changing temperature enhances analyte separation and reduces cycle time.  Considering this, the heating element must be sized properly and have sufficient wattage to sustain the power requirements of the ramping temperature profile at all points along the ramp.

For more information about the application of resistive heaters for gas chromatography, contact a BCE applications engineer.

High Temperature 16 Pair Type J Thermocouple Feedthrough

16 Pair, High Temp Type J Thermocouple Feedthrough

BACKGROUND

A 3D Printer company specializing in Aerospace parts provided BCE a challenge in creating a High Temperature Feedthrough for their new composite 3D printer.  The 3-D composite company needed a high enough temperature in the sealed area with a vacuum chamber being essential in printing aircraft components.  They had difficulties integrating their existing thermocouple design into their expanded chamber with an off the shelf feedthrough.

SCOPE

The 16 (32-wire) Pair Thermocouple feedthrough needed to satisfy the following:

• Operating temperatures between -25 C to 300 C
• Low vacuum leak rate of 10^-9 ATM-CC/S or better
• Able to withstand a 450 C Bake-out temperature
• Type J thermocouples (customer preference) with ring terminations 
• Fiberglass lead wires to withstand the high temperature

OUTCOME

BCE successfully designed a Thermocouple Feedthrough with a type J T/C extension wire so that the customer could integrate the component with ease into their 3D Printer. The High Temperature Feedthrough went through extensive pressure and temperature cycling before being shipped.  One final helium leak check was made and a polarity verification for all connectors was done too.

For more information, contact BCE by calling 510-274-1990 or by visiting https://bcemfg.com

Copper Flange Heater for Gas Chromatograph

A gas chromatography application was brought to BCE involving a custom heater to ramp a cell end plate to 105°C. The customer had issues finding a solution due to the small surface area that needed to be heated (~ 0.75” diameter).  The requirement was a 25-Watt 120-Volt source, which resulted in a high resistance value (576 ohms) eliminating many heater options for this size and surface area.

Scope:

• Heater plate to be 105°C 
• Good temperature uniformity (+/- 1.5%C)
• 25 W 120 V
• 1/8” Plate thickness max
• Geometry to allow for three tubes to exit
• 0.75” Diameter

Outcome:

Since etched foil polyimide heaters were not an option for this application, BCE engineers designed a 110 copper plate with a rod heater welded within the groove.  The rod style heater allowed for a higher resistance value and was more robust compared to other types of heaters.  Additionally, the cold section and lead orientation can be easily modified by the customer to accommodate their assembly.  BCE’s Copper Flange Heater was able to efficiently heat the small surface and save the customer from an expensive assembly redesign.

For more information, contact BCE by calling 510-274-1990 or by visiting https://bcemfg.com