This vlog is based on a previous blog we posted called “Temperature versus Heat Loss in a Heater”. In this video, Thermal Corporation Engineer, Kyle Otte, explains how to calculate the exact wattage needed for any type of industrial heater for your heating process.
How Wattage Is Calculated
The Rate of Energy Consumption equation above is used to calculate the wattage, where
E is the energy required for the process (or the total watts needed)
Why We Urge to Avoid Contamination of Industrial Heaters
This video topic focuses on why it is so important to make sure that your heaters do not get contaminated by substances. Contamination causes industrial heaters, like this ceramic band heater, to fail very quickly and have an extremely short heater life.
Related Blog Posts on Extending Heater Life
We have several blog posts that go into more detail on how to extend the life of specific types of industrial heaters like cartridge heaters, mica band heaters, and strip heaters. If you are interested in checking them out, they are listed below:
The Differences Between Band Heaters: Mica Bands vs Ceramic Bands
There are two types of band heaters that Thermal Corporation manufactures: mica band heaters and ceramic band heaters. There are strong points with each type, and the general differences are laid out below:
Temperatures
Ceramic band heaters can withstand a higher temperature than mica band heaters. Ceramic band heaters have a maximum operating temperature of 1200⁰F vs a maximum operating temperature of 800⁰F for a mica band heater.
Heater Life
Ceramic band heaters typically (but not always) have a longer life expectancy. This is due to the coiled resistance wire that is fed through ceramic blocks (called knuckles) vs. the thin resistance ribbon that is used in mica band heaters. The coiled resistance wire has a smaller ratio of surface area to internal cross-sectional area and thus doesn’t really oxidize and burn through as fast as the ribbon.
Watt Density
Mica band heaters can have a higher watt density than ceramic band heaters. Because the resistance ribbon in a mica band heater is tightly clamped between pieces of mica, there is better heat transfer from the ribbon to the exterior surfaces of the heater. Also, in general, mica band heaters will have less unheated area than a ceramic band heater, especially in smaller band heaters.
Customizability
Mica sheets can be cut into custom shapes and sizes, whereas ceramic band heaters are limited by the size of the knuckles. Because of this, mica band heaters are also much more customizable when it comes to dimensions. Ceramic band heaters are limited to 1/2″ width increments, whereas mica band heaters can be any width within the upper and lower limits of at least 1″ by 1″, depending on the specific mica band configuration.
Pricing
Ceramic band heaters are more expensive than mica bands. The ceramic knuckles are quite expensive when compared to the thin sheets of mica that mica bands are constructed from. However, this difference may be compensated for by the increased efficiency of the ceramic band heater.
Insulation Options
Standard ceramic band heaters have one layer of 3/8″ thick ceramic paper insulation over the knuckles, and then a stainless-steel outer sheath that reflects heat back into the process. The “Heat Saver” ceramic band insulation option has one layer of 1/8″ thick ceramic paper topped with a reflective stainless-steel sheath, and then an additional 2 layers of 3/8″ thick paper, topped by an additional sheath. All of this insulation yields a higher efficiency heater vs. a mica band heater. Ceramic band heaters also offer a “Vented Outer Sheath” option, seen in the image below. This allows heat to escape from the process, if needed for your application.
Closing Remarks
In conclusion, you just need to examine your heating process and specific needs for a band heater and decide between a mica band heater or a ceramic band heater. If we can be of any assistance, please let us know. Mica bands are cheaper, can have higher watt density, and are more easily customizable. Ceramic bands are more efficient, can withstand higher temperature, and generally last longer.
In this video, Kyle Otte gives some tips on how to extend the life of your Thermal Corporation band heater. These tips include those such as: handling the band heater with care, avoiding excessive cycling, and process temperature limits for both mica bands and ceramic bands.
The mica band heater used in this video features our NEW! Latch and Trunnion Closure System! For more information about our latch and trunnion option for band heaters, read our blog post!
To request a quote for a mica band heater, click here! Direct any questions you have to our customer service department by phone at (800) 633-2962, by email at sales@thermalcorp.com, or by using our instant chat feature located at the bottom of the page.
A few weeks ago, we published a blog post and sent out an email to our subscribers about a new band heater option: the Monel sheath. Thermal Corporation is proud to announce a second new band heater option this Fall. We can now manufacture our high temperature mica band heaters with a latch and trunnion closure system attached to the heater! We have had several customers request this option in the past, and once again we, at Thermal Corporation, have listened.
Latch and Trunnion Closure System
A latch and trunnion closure system allows for quick closing of a heater and eliminates the time consuming process of starting a bolt into a threaded barrel nut. Once the latch is secured, a nut is tightened against a spring, which provides a constant closing force even as the band heater expands on startup.
Construction of a Latch and Trunnion
Our technicians begin construction by using a stainless steel outer sheath and welding stainless steel tabs onto the sheath. This gives us the ability to roll the heater before we attach the latch and trunnion system. This is an important step in making the heater the appropriate diameter per the customer’s specifications. The latch and trunnion is too bulky to go through the rolling process, thus it must be attached once the band is already rounded.
Direct Questions to Our Technicians
Our technicians can answer any questions you have about this new option. Contact our band heater product technician, Matt Blackburn, by email at matt.b@thermalcorp.com or by phone at (800) 633-2962 x153.
Future Options
What would you, as our customer, like to see offered next? Any suggestions for a product or option that you would like to see us start offering in the near future can be directed to our sales and customer service department. Thank you and we appreciate your business!
Written by Kyle Otte and Shelby Reece Edited by TC Marketing Team Date Published: 08.16.2019 Last Updated: 08.16.2019
Monel Option Now Available for Thermal Corporation Band Heaters
You Asked, We Listened!
Thermal Corporation is now offering a new option for our mica band heaters — sheaths and straps made from Monel material!
What is Monel?
Monel is an alloy that is primarily composed of nickel and copper. It also contains small amounts of iron, manganese, carbon, and silicone. Monel’s appearance is similar to that of stainless steel. Because of its resistance to corrosion and acids, Monel is often used in caustic atmospheres.
Several of our Thermal Corporation customers have requested band heaters with Monel sheath. And we listened! Thermal Corporation can now make band heater sheaths, both inner and outer, out of Monel! We can also use the Monel material to construct band heater straps.
Interested in More Information Regarding This New Option?
A customer phoned our engineering department here at Thermal Corporation complaining that he was experiencing very poor life with a mica band heater– a life of only one week! He explained that the application was to heat a flange that was attached to a gate at the end of an extruder. The extruder was adding a layer of nylon to wire-in cross-head die. The flange sat between the gate and the cross-head die. (The cross-head die had its own separate heater.) The flange also had a thermocouple, extending radially, out of it. The application looked something like the image you see below.
The flange had a width of 1″ or so and a diameter of 5″. The mica band heater was our configuration 514 with a hose at 90° from the gap. This gap measured 1/2″ to accommodate the thermocouple. The heater the customer had been using had 675 watts at 240 volts. The watt density of this heater was 66.5 watt/in2 and the operating temperature was 520°F.
What questions should we ask? What could we recommend?
Based on the diameter and operating temperature, the maximum watt density for this heater should be in the mid-30’s. The watt density the customer was getting was twice that (at 66.5 watts/in2). Earlier, Thermal had supplied the heater with 500 watts (49.3 watts/in2), but this heater did not last either.
By looking carefully at the flange width, we noticed that the width of the flange was about 11/4“. The mica band heater we had been supplying had only a 1” width. Next, we looked at the configuration of the mica band. A configuration 500, while not providing much more heated area, did provide a lower ribbon, or wire watt density. Then, we examined how much heat was required to control the process. Looking at the ammeter (a meter which displays the current being drawn by the heater), we saw that the heater was staying on for a total of 8 seconds. Then, it was turning off for only 6 seconds before turning on again. This means that the heater was on for 8/(6+8)%, or 57%, of the time. Thus, the heat required to control the process was 57% of the 675 watts, or 385 watts. To provide a safety margin, we would want to add 15% or so more heat to this minimum in the heater.
Therefore, with the wider width and the change in configuration from 514 to configuration 500, we could get 450 watts in the heater with a watt density of 33.25 watts/in2. We made a sample of this configuration for the customer to try.
Additional Notes
We also noticed that in the process, following the cross-head die, was a laser sensor used to measure the diameter of the nylon coating. Because the smoke from the extrusion process got on the laser sensor lens, the customer had installed a fan. The purpose of this fan was to blow the smoke away from the lens. As it turns out, the fan was blowing directly on the heater and the gate it was attempting to heat. This increased the heat loss and the heat required from the heater. The customer agreed to place a shield, if needed, between the fan, and the heater and gate. This would most likely permit the wattage and watt density to be further reduced.
Written by Jim Dixon and Shelby Reece Edited by Kyle Otte Date Published: 07.19.19 Last Updated: 09.03.19
Our resellers, along with our other valued customers, are one of the major parts of Thermal Corporation and what help keeps our company going. We, at Thermal Corporation, are always looking to reach out to new resellers for our products. Our goal for this post? To grab your attention — if you are a part of an industrial heating sales company who is interested in buying and reselling Thermal Corporation products, then this post is for you!
What We Sell
As you may already know (or not), Thermal Corporation designs, manufactures, and sells industrial heating products. The types of industrial heaters we manufacture can be standard, or designed to exact customer specifications. Our products are used mainly for the plastics industry, but can also be used for other industrial applications such as food processing. These products include:
Our delivery time is second to none! Ask about our express line of heaters that ship on the same day with no extra cost! Limitations do apply. We also specialize in custom and unique heaters. We can provide these heaters with short lead times.
How to Become a Reseller
So, are you an industrial heating sales company looking for new product categories to offer or who wants more of a variety of brands to sell? Then, contact Thermal Corporation today and chat with us about becoming one of our resellers! Don’t forget about the discount you can receive if you decide to resell Thermal Corporation products. Resellers have the opportunity to get the largest available discount from Thermal Corporation. Discounts are based on annual sales of Thermal Corporation products.
Thermal Corporation is looking to reach out to new possible resellers right now! Need more specific information on our products? Check out the products page on our website at www.thermalcorporation.com/products.
Interested in chatting with us and getting more information about doing business with Thermal Corporation? Contact Ushma today by email at ushma.s@thermalcorp.com or by phone at 256-837-1122 x127.
Written by Shelby Reece Edited by TC Marketing Team Date Published: 03.04.2019 Last Updated: 09.04.2019
Moisture is one of the most immediately noticeable contaminants. If sufficient moisture is present at start-up, the heater fails as soon as power is applied. Sometimes, when the heater has been cool for a prolonged period and has been subject to a high humidity environment, there will be enough moisture absorbed to cause failure at start-up. When insulated lead wire has gotten wet near the heater, the moisture can be wicked into the heater and cause failure. Anytime heaters fail as soon as the power is supplied, moisture is a strong suspect as the culprit.
Oil and other organics can cause heater failure if they get inside the metal sheath, but they behave differently than water. Most oils and organics do not conduct electricity very well as lower temperatures, but carbonize and become conductors at elevated temperatures. Thus, if such contaminants are present, the failure occurs only after the heater has gotten hot enough to cause carbonization. Like water, oil that gets on the lead wire insulation can be wicked into the heater.
#2 Avoiding Over-Temperature
A loose fit of the band heater on its cylinder will reduce the heater’s lifetime because the heat generated is not transferred efficiently to the cylinder being heated, causing the heater to run at a higher temperature to transfer its energy. The higher the operating temperature, the shorter the lifetime. It is good practice to retighten the clamping strap or clamping tabs after the first time that the heater has been used, because the heater will be better conformed to the cylinder during its first heat-up. Anything that prevents a smooth fit of the heater on the cylinder, such as a cylinder surface irregularity, will shorten the life of the heater because the net effect of the irregularity is to make a “loose fit” in spots.
Choose the lowest wattage heater than will maintain the desired operating temperature of the cylinder being heated and still provide a short enough start-up time. Choosing a heater with higher wattage than required will result in the controller turning the heater on and off to maintain the desired temperature and a higher operating temperature during on-time. These conditions will shorten the heater life.
#3 Excessive Cycling
The way that Thermal Corporation evaluates the lifetime of their own band heaters and those from competitors is to cycle the units from 150°F to 900°F and count the cycles to failure. Cycling reduces lifetime because the surface of the element wire oxidizes rapidly at higher temperatures; if the higher temperature is maintained, the oxide coating actually protects the wire from further rapid oxidation, but if the wire temperature is reduced substantially, the oxide coating breaks off due to contraction and exposes fresh metal to more oxidation. With continuous cycling, the wire diameter is eventually reduced, and the resistance of the element is increased to the point that it becomes too hot. At that point, the element wire either melts and breaks open the circuit, or it causes the insulation over the wire to break down, causing a short to the sheath.
#4 Physical Abuse
Never carry a band heater by the lead wires. If the heater has post terminals, use two wrenches; one to hold the bottom nut and one to do the tightening on the top nut.
Edited by Shelby Reece Date Published: 07.05.2018 Last Updated: 09.06.2019
is the change in temperature (°C)
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Discounts are based on annual sales of Thermal Corporation products.
