Continuous conveyor ovens are widely used in a variety of industrial processes including composite curing and heat treating. The entrance and exit points of these ovens represent significant areas for potential heat loss and energy inefficiencies. Without a proper heat barrier system these openings can be the culprit for thousands of dollars in wasted energy cost. In addition, regulating and controlling critical process temperatures can become a daunting task with inadequate heat containment.
Utilizing Worbo’s unique high temperature strip curtain system, energy costs may be significantly reduced and process temperatures may be accurately controlled. These strip curtains serve as an effective thermal barrier while allowing for the passage of parts through the oven chamber. Unlike traditional PVC strips that will break down at moderate temperatures the Worbo solution can withstand excessive temperatures and will continue to function effectively up to 1000oF.
A typical example of a proven and extremely effective Worbo strip curtain design consists of a double layer heat barrier system. In this system the inside face of each strip if fabricated from Worbo’s exceptional Eko-ThermTM heat reflective material. This unique material serves to retain convective heat with in the oven chamber in addition to preventing radiant heat from escaping through the oven door. The outside face of each strip is fabricated from Worbo’s extreme duty MSA96 (96 oz/yd2) silicone coated fabric offering outstanding durability and abrasion resistance as moving parts are transferred though the oven opening.
In addition to generating significant energy cost savings, Worbo’s high temperature strip curtains offer the following key benefits:
Strips are easy to install and individual strips are simple to replace should they become damaged without the need to replace the entire curtain.
Excellent abrasion resistance and exhibit outstanding durability as parts move in and out of a conveyor oven.
Allows for oven temperatures to be accurately controlled ensuring product consistency and quality is upheld.
Manufacturing cycles are increased as the thermal barrier facilitates faster oven pre-heat time.
Strip curtains may be supplied in a variety of widths and lengths to custom fit virtually any oven opening.
Worbo’s heat resistant strip curtains are tailor made for each specific application in consideration of temperature constraints, environmental conditions, cycle frequency, oven geometry, etc. Contact the design team at Worbo to assist with your continuous conveyor oven application.
In response to a growing demand from our customers, Worbo is excited to announce the release of a new product line of easy to install elbow and tee insulation sleeves for high temperature applications. Introducing Cool-Skin elbows and tee sleeves by Worbo.
These products offer a fantastic complement to our extremely popular line ofCool-SkinTM sleeves. They are a perfect solution for insulating hoses and process lines that contain a tight bend radius or for lines that have tee intersections. Traditionally it has been a challenge for plant engineers and insulation contractors to provide a satisfactory and effective thermal barrier in these areas. Worbo’s wonderfully simple solution enables our customers to quickly and easily install these removable Cool-SkinTM insulation components around elbows (from 45’s to 90’s) and at tee junctions. They offer a very precise fit around a wide variety of diameters to maximize insulation coverage to minimize heat loss and to prevent burn injuries at these tricky locations.
Cool-SkinTM elbows and tees are fabricated from the same tried and tested materials that make up our existing Cool-SkinTM sleeve products. They are equipped with a durable abrasion resistant jacketing system that encapsulates a clean non-fibrous insulation medium exhibiting an extremely low thermal conductivity to provide a very efficient thermal barrier. As with many of our Cool-SkinTM products our elbows and tees are supplied with a hook and loop closure for easy installation and removal.
For applications where radiant heat is a concern our Eko-ThermTM jacketing system may be supplied as an alternative to the standard yellow jacket. The combination of our shiny aluminized Eko-ThermTM material coupled with our non-fibrous insulation medium offers an effective barrier from conductive heat sources as well as from radiant heat sources. Up to 90% of radiant heat will be reflected away from the low emissivity and shiny surface of the insulation component. This doubly effective technology will ensure that the process temperatures can be accurately maintained with a minimal insulation wall thickness.
This new exciting line of products is yet another example of the how the Worbo research and product development team has demonstrated out of the box thinking to create cost effective and innovative thermal protection solutions.
Here at Worbo Inc., we are often asked by our customers to design and supply insulation components for unusual or unique high temperature applications. We pride ourselves on our ability undertake these unique challenges and to deliver effective thermal barrier solutions.
A critical step to determining the most effective type of thermal barrier system is to understand the mode of heat transfer within the application. It is generally recognized that heat travels from areas of higher temperatures to areas of lower temperatures but it is important to also understand the mechanism for this heat flow. Heat may be transferred by one of three (3) possible modes: thermal radiation, convection or conduction. Depending on the application it is often feasible that heat transfer will occur through more than one of these modes.
Our engineering team must review each application individually to gain an understanding of the modes of heat transfer and how they relate to the required thermal objectives. Once armed with this information, our engineers will begin the detailed design phase to determine the appropriate material construction, thickness and type of thermal barrier that will produce the desired outcome.
Thermal Radiation (Electromagnetic Radiation)
All objects or materials that have a temperature greater than absolute zero will emit electromagnetic waves through a process called thermal radiation. Here’s how it works à all matter (above absolute zero) contains kinetic thermal energy that is produced by atoms and molecules interacting with each other. The continuous interaction between charged particles within these atoms leads to the emission of protons radiating energy away from the boundary surface in the form of electromagnetic radiation. It is important to note that this electromagnetic radiation can travel through an air space and it does not require the presence of matter for its propagation.
Examples of thermal radiation would include the heat that can be felt from a racing car exhaust even a few feet away or the intense heat that radiates from a molten iron blast furnace.
An effective way to inhibit the transfer of heat by thermal radiation is with a reflective insulation barrier that reflects electromagnetic radiation away from its surface. The property of a material that characterizes its ability to prevent radiation heat transfer is called surface emissivity. The lower the surface emissivity the more effective a barrier is at reflecting radiant heat. Worbo’s Eko-ThermTM blanket material is an excellent example of a very good reflective insulation barrier. It is supplied with a shiny aluminized surface that has a very low emissivity and is capable of reflecting up to 90% of radiant heat away from its surface.
Unlike thermal radiation that occurs through an air space, conductive heat transfer only occurs when two bodies (with different temperatures) come into contact with each other. A body with a high temperature has an abundance of thermal energy that is generated from the rapid collision of particles within the material. Thermal conduction occurs when fast-moving particles of a warmer material collide with slower-moving particles of a colder material. These collisions cause the slower moving particles of the colder material to speed up thus increasing its temperature, and the faster moving particles of the warmer material to slow down resulting in a lower temperature.
An example of conductive heat transfer occurs when an employee sustains a skin burn from accidental contact with a hot process line.
When considering conduction it is important to understand that not all materials are created equal. Some materials are more effective at conducting heat than others. The ability of a material to transfer thermal energy is measured though a property called thermal conductivity. Materials with a low thermal conductivity such as fiberglass or Styrofoam have a lower capacity for heat transfer and therefore these materials are often utilized as thermal insulators. Worbo Inc. offers a wide variety of effective thermal insulators that exhibit very low thermal conductivity including our InsulmatTM and Cool-SkinTM products. What differentiates these Worbo products from residential grade materials is that they are effective at elevated temperatures. Unlike residential insulation materials these products won’t break down when exposed to extreme temperatures.
The final mode of heat transfer is convection. Convection is a means of transferring thermal energy into or out of an object by the physical movement of a surrounding fluid (liquid or gas). When a fluid is heated it expands and becomes less dense and lighter than the surrounding fluid. The lighter fluid then rises. The cooler fluid rushes in from the sides where it is heated and rises creating a convective column. This process repeats itself, resulting in a continuous convection current in which warmer fluid moves up and away from a heat source and cooler air rushes down toward the heat source.
An example of convective heat transfer occurs when an overhead crane charges a furnace in a steel producing facility. The extreme heat from the charging furnace rises in a convection column toward the crane which can expose the cranes power cables to intense heat.
Among one of the most innovative of Worbo’s thermal protection solutions is the development of a unique festoon cable protection system. This system has been implemented in steel mills around the world and has proven to be a very effective solution to prevent damage to overhead crane power cables from extreme convective heat. In addition, this robust system provides an excellent barrier to protect against molten metal splash.
Often a thermal protection system will need to address all three (3) modes of heat transfer to produce the best possible outcome. Worbo Inc. has an extensive array of materials each with its own unique thermal properties, specifically designed to mitigate the potential negative impact of heat transfer. The best possible insulation system will quite often utilize a combination of select Worbo materials to create a successful insulation solution.
The engineers and designers at Worbo Inc. understand the complex nature of high temperature problems and they are very good at analyzing specific applications to develop effective solutions.
It is not uncommon for electrical cables in heavy industrial centres to be vulnerable to heat exposure.
Worbo was approached by a steel refinery to develop a thermal protection system for flexible power cables. These cables were in close proximity to extreme infrared radiant heat and flames.
Worbo Engineers were able to develop a customized solution employing Worbo’s Eko-Therm™ technology and high temperature velcro enclosures resulting in a flexible, removable thermal barrier sleeve providing complete thermal protection for the adjacent power cables.