Category Archives: Design capability

High Temperature Strip Curtains

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.

Worbo strip curtain
Worbo strip curtain

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.

 
MSA96 side of strip curtain
Outside face of strip from extreme duty MSA96
 
Eko-Therm side of strip curtain
Inside face of strip from heat reflective Eko-Therm

In addition to generating significant energy cost savings, Worbo’s high temperature strip curtains offer the following key benefits:

  • Reduce the risk of workplace burn hazards near the opening of the oven.
  • 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. 

 

Attention HMA Plant Operators

Reduce energy cost by 68% with Cool-SkinTM insulation sleeve on hot oil “jumper” hoses.

A typical Hot Mix Asphalt (HMA) plants makes use of hundreds of feet of flexible metal “jumper” hoses to transfer hot oil across connection flanges. These hoses are frequently overlooked by insulation contractors as they usually have a tight bend radius and they are difficult to protect.  In addition the neglected jumper hoses are often considered unimportant because they represent a small portion of the hot oil system.  The reality is that these un-insulated lines result in huge inefficiencies and cost thousands of dollars in wasted energy.  This would is similar to leaving a window open all winter long.  It just doesn’t make good sense.

uninsulated jumper hose

Worbo has developed an effective thermal insulation solution that enables HMA plants to recover significant heat losses on small diameter and tight radius hoses with ease.  Introducing Cool-SkinTM sleeve! 

cool-skin sleeve on jumper hose

Unlike traditional methods such as mineral wool and hard aluminum cladding, Cool-SkinTM is easy to install and does not require expensive insulation contractors.   A hook and loop self gripping fastener is incorporated into its design allowing operations staff efficient access to process lines while performing maintenance procedures or trouble-shooting system components.  Once line interruption is complete, Cool-Skin™ is simply re-installed in a few short seconds. 

An additional important and impressive benefit to the Cool-SkinTM technology is that it incorporates a closed cell insulating structure that will not absorb water or moisture making it an effective insulator even in wet conditions.

Ongoing field monitoring has proven that insulating a flexible metal hose (1 ½” OD) with Worbo’s Cool-Skin™ sleeve at a typical HMA plants will reduce heating cost an average of $30 for every foot of jumper hose in just one short seven (7) month operating season.  In most cases Cool-Skin™ pays for itself within the first four (4) months of installation.

Contact the Worbo team to learn more about how Cool-SkinTM can reduce energy costs at your HMA plant.

Cool-Skin Elbows and Tee’s

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 of Cool-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-Skin 90 elbow
Cool-Skin 90 elbow
 
Cool-Skin 90 elbow
Cool-Skin 90 elbow
 
Cool-Skin Tee
Cool-Skin Tee
 
Cool-Skin 45 elbow
Cool-Skin 45 elbow

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.

Eko-Therm elbow
Eko-Therm elbow

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.   

 

 

Holding It Together

Here at Worbo Inc. we pride ourselves on providing top quality custom fabricated high temperature insulation components for process lines and equipment. In our view, an essential characteristic of a successful insulation cover is that it must be user friendly. It should be easy to install and easy to remove and reinstall for maintenance. This eliminates the need for expensive insulation contractors and minimizes the loss of valuable production time. Ease of installation is often achieved through the implementation of simple and effective mechanical closures. At Worbo we offer a wide range of fastening systems to create easy to install insulation components that are suitable for thousands of high temperatures applications.  Here’s how we “hold it together”.

 

Grommets and Wire Ties

This method for securing a Worbo insulation component in place employs the use of high temperature grommets in combinations with wire ties. It often consists of a series of grommets (ranging in diameter from ¼” ID up to 1” ID or larger) placed around the perimeter of an insulation component. Grommet holes on one side of an insulation cover will line up with adjacent grommet holes on the opposite side of the cover and will be joined together with a wire tie or metal banding. In many cases this is can be the most cost effective solution.

grommets on Worbo high temp curtain
grommets on Worbo high temp curtain
grommet and wire tie closure on high temperature festoon cable protection system
grommet and wire tie closure on high temperature festoon cable protection system

 

Grommets and Carabiners

In the case of a high temperature insulation curtain application, grommets may be used in combination with spring snap carabiners.   This mechanism will enable a curtain to be suspended from a supporting rod or structure and it will allow for the curtain to slide back and forth creating an access opening when the curtain is not in use. A simple “S” hook also works well for this application as a substitute for the carabiners.

carabiners on high temperature insulated curtain
carabiners on high temperature insulated curtain
high temperature curtain
high temperature curtain

 

Hook and Loop

This is one of our favorites and it comes standard on our Cool-SkinTM sleeve line of products. High temperature hook and loop (Velcro®) is a fantastic closure option that may be exploited on a huge assortment of insulation components.   It’s simple and dynamic. We offer hook and loop in a broad array of widths from as narrow as a ½ inch wide up to six inches wide and beyond. It is available in various profiles that can maximize gripping strength or maximize opening and closing cycles depending on the application. A hook and loop closure provides a very good seal to allow for maximum heat retention and it can be incorporated into virtually any configuration of insulation cover. Thanks for the invention George de Mestral, great idea!

Cool-Skin cover with hook and loop closure
Cool-Skin cover with hook and loop closure
High temperature sleeve with hook and loop
High temperature sleeve with hook and loop
Worbo MSA curtain
Worbo MSA curtain

 

¼ Turn Fasteners

Another great option is the ¼ Turn or Common Sense fasteners. These are great for creating a strong mechanical union between two mating surfaces. They are particularly effective in situations where ease of installation and maximum connections strength are critical. Here’s how it works….a small turnbutton post is secured to the perimeter edge along one side of an insulation cover. This post is then inserted through an oval eyelet mounted on the opposite side of the cover and then it is simply rotated 90 degrees to lock it in place creating a mechanically positive attachment.   The photo below illustrates how this closure works on a trolley skirt installed on an overhead crane festoon protection system.

quarter turn fasteners on high temp trolley skirt
quarter turn fasteners on high temp trolley skirt

 

D-rings and Straps

D-rings and straps are a fantastic option for providing a very snug fit between an insulation sleeve and a hot process line to ensure that heat retention is maximized. This mechanism works in a similar fashion to a chin strap on a standard motorcycle helmet. A high temperature tension strap is inserted through two d-rings that are secured to an insulation component. The strap is then fed back between the two d-rings and pulled tightly. By drawing the strap firmly, this mechanism ensures that the insulation component will fit tightly around the process line. This system also allows for some flexibility with respect to the size of the components being insulated and often a single insulation part may be used for multiple process lines. In this scenario an insulation sleeve is overbuilt to accommodate a largest possible shape and then it may be drawn in with the straps and d-ring arrangement to fit snugly around a smaller line. In many cases this is a one size fits all solution.

d-rings and strap on high temp cover
d-rings and strap on high temp cover
high temp cover for plastic extrusion line
high temp cover for plastic extrusion line

 

Lacing

This is another great low tech option that offers an effective and inexpensive solution for securing an insulation component in place. As with the d-rings and strap method the lacing option will provide a forgiving range of adjustment to allow for a tight fit around various sizes and shapes of equipment.

lacing on a Worbo insulation cover
lacing on a Worbo insulation cover
lacing on an MSA cover
lacing on an MSA cover

 

Zippers

A high temperature zipper is yet another option for securing an insulation component in place. Below is a photo of a zipper that has been effectively utilized in a bellows style insulation boot. The boot has been designed to protect a hydraulic cylinder from molten splash and it is easily installed without disassembling any of the heavy equipment. Notice that the zipper has been secured to the boot in a spiral fashion along its length. This allows for the zipper to be offset between each the corrugations of the bellows to ensure that when the bellows is collapsed it occupies the minimum amount of space.

Worbo high temp bellows with zipper
Worbo high temp bellows with zipper

 

Combination of Different Closure Mechanisms

When one type of closure just won’t do to the trick we can easily incorporate multiple closure mechanisms into a custom fabricated high temperature insulation component for maximum thermal protection and minimum heat loss.

grommets, quarter turn fasteners and hook and loop
grommets, quarter turn fasteners and hook and loop
draw string and d-rings with strap
draw string and d-rings with strap
zipper and hook and loop
zipper and hook and loop

At Worbo one of our primary business objectives is customer satisfaction. We believe we can achieve this through providing high quality and cost effective insulation components that are easy to install. Our expertise and experience with a large assortment of closure mechanisms and fastening systems allows us to provide easy to install components that satisfy our customers.

Understanding Heat Transfer: Radiation, Conduction and Convection

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.

extreme temperature  exhaust
Hot exhaust
blast furnace curtain
Radiant heat from a 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.

Eko-Therm sleeve
Eko-Therm sleeve
Eko-Therm Curtain
Eko-Therm Curtain

Conduction

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.

Caution%20Hot%20surface

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.

Insulmat 2300
Insulmat 2300
Cool-Skin Blanket
Cool-Skin Blanket

Convection

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.

Overhead crane used to charge furnace at Steel mill
Overhead crane used to charge furnace at Steel mill

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.   

NPT Cable Connector 014
Festoon cable protection

 

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.