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Why Cartridge Heaters Fail

One of the key ways to lower equipment costs for any business it to make sure that each piece of equipment last as long as possible. And when it comes to heating equipment this can be quite a challenge. Logic would suggest that equipment such as cartridge heaters would naturally have a short life due to their very nature. However, cartridge failure is not always due to age. There are other factors that can lead to their failure. Here we outline some of the most common reasons why this happens and offer our top tips on how to prevent cartridge heater failure in the future.

  • Improper fit: Perhaps the most common cause for cartridge heater failure of all is improper fit. If a heater cannot dissipate the heat to the outside of its sheath properly the temperature will rise until it ultimately fails. Eventually, this will cause a breakdown of wires and heater itself.
  • The watt density is too high: All cartridge heaters have a voltage at which they are designed to work. Outside of this voltage rating they may be ineffective or may fail eventually. So, if the applied voltage is too high then this will increase the watt density of the heating element. This will result in heat not being dissipated in the way that it should. The result can be that the unit fails to operate.
  • Frequent temperature cycling: Excessive temperature cycling places undue stress on cartridge heaters. This can cause them to expand and contract at a fast rate (i.e. every 30-60 seconds). Eventually, this will reduce the lifespan of your heating element.
  • Moisture and impurities: These elements can be drawn into your heating cartridge from the surrounding environment. These two elements can often cause a short circuit to occur which can lead to the heater failing.
  • High temperatures and excess movement: Cartridge heaters can also be damaged by two other external factors – high temperatures and excess movement. To give your heater an added level of protection, make sure that you supply it with a suitable level of insulation when it is mounted onto moving machinery. In other words, the heating element should be as stable as possible or at the very least protected from excess movement which can lead to an eventual breakdown.jobco

The takeaway from all this is that just because your cartridge heater has a difficult job to perform does not mean that it has to burn out quickly. When certain precautions are taken your Watlow cartridge heater can have a life that is as long as any other vital equipment you own. Moreover, our customer cartridge heaters are made to fit the needs of all kinds of businesses. Check out our models and the specs and you will see how they can be an asset to your company.

Spotlight on Watlow Electric Manufacturing Company: Powered by Possibility

One of the manufacturers we are proudest to be associated with is Watlow Electric Manufacturing Co. We sell their high quality products to the industrial sector with pride and confidence that clients will receive machine and machine parts that will perform at or above their expectations. We admire the company for their constant efforts at perfection in the products they produce. But innovation and excellence such as that achieved by Watlow Electric Manufacturing Company does not happen overnight nor is their story a simple one. Here is a little about one of our manufacturers that we hope will inspire your company as you peruse our products such as our hot air heater and oil tank heater blanket.

History

Watlow is a family owned business that began back in 1922 when its founder rented a space on the second floor of a machine shop and began making electric heating elements for the shoe company. The St. Louis businessman/inventor – Louis Desloge Sr. – eventually began selling his products locally then expanded beyond the local market during the 1930s and 1940s. HIs first innovation came with the swaged cartridge heater which improved heat transfer efficiency greatly. This innovation and his company’s hard work formed the basis of him expanding to a 185,000 square foot facility eventually.

Whereas some companies rest for some time on one accomplishment, innovations continued throughout the next several decades for the Watlow Company. For example, it introduced the first thermocouple product back in the 1970s. Thermocouples have the ability to accurately measure extreme temperatures, with ranges from 270 to 2,500 degrees Celsius, and errors within 0.5 to 2 degrees Celsius and are used in gas appliances such as boilers, water heaters, and ovens.watlow

Today and Tomorrow

Today, the company continues to innovate with products such as its new F4T with INTUITION, a touch-screen controller that combines the functions of several devices into one process control. It also continues to provide products to numerous industries, including semiconductor processing, environmental chambers, energy processes, diesel emissions, medical and foodservice equipment. Moreover,, Watlow holds more than 450 patents and currently employees more than 2,000 employees who work in many parts of the world.

Finally, we know that your company will be well served by any of the Watlow products we sell on our site as your company makes its own push towards excellence and innovation.

Tips for Handling Cold Weather Equipment Failure

In all the industries that we serve it is critical that owners be able to keep their equipment at a specific temperature. Unfortunately, that responsibility becomes difficult to fulfill when cold weather sets in. Our coil heaters, band heaters, ring heater, hot air heater etc are products that can help businesses stay productive and avoid the loss of time and money. If you use cartridge heaters, for example, in any of the following applications you can relate to this problem in particular:

  • Immersion tank heating
  • HVAC compressors
  • Fuel cells
  • Semiconductors
  • Medical devices
  • Sensor measurement devices
  • Extrusion
  • Die casting
  • Hot melt adhesives

But what do you do for equipment that has failed because your current heating product has stopped working due to cold weather, etc? Here are our suggestions for business owners.
temperature
Troubleshoot the equipment: The first step is to properly diagnose the problem. This is should be done with the goal of getting the machine up and running as soon as possible so as not to slow down productivity. Often, if a particular malfunction has occurred often and has been diagnosed in the past, then the whole troubleshooting process can be shortened considerably. Trouble shooting should involve:

  • Verifying that a problem exist
  • Narrowing down the cause(s)
  • Correcting the problem
  • Work to prevent future issues

On the last point, we can help you by supplying you with products that will help your equipment run smoothly.

Implement a contingency plan: It is wise at some point to have a contingency plan in place if a major piece of equipment does break down. This way, your business will be able to save product, by switching to the temporary solution. Hopefully, your business will have planned for a contingency such as equipment breakdown.

Finally, many problems that involve heat product related breakdown are caused by owners failing to purchase and maintain the proper equipment. On our site, we will help you choose the right equipment for your industry and for the machine (s) you need to keep up and running.

Cartridge Heater Lead Wires

Lead Wire Type Temperature Rating Comments Products
Duraflex 1022° F/ 550° C Excellent all around wire. Flexible, easy to strip. Not waterproof. Standard on all cartridge heaters, band heaters, strip heaters. Optional on silicone rubber heaters.
TGGT 482° F/ 250° C Durable, not waterproof. Optional on all heater products
Teflon 482° F/ 250° C Easy to pull through conduit, abrasion resistant, waterproof. Smaller OD than other wire types. Standard on silicone rubber heaters. Optional on all others.
Silicone Rubber 302° F/ 150° C Very flexible, water proof. Nicks easily. Optional on all heaters. Forms excellent moisture seal when used with RTV potting.
Braided Silicone Rubber 392° F/ 200° C Very flexible, waterproof. More abrasion resistant than plain silcone, but less so than other types. Standard on nozzle heaters, optional on all others.
HPN Cord 194° F/ 90° C Inexpensive, compact two conductor cord. Sometimes called lamp cord. Optional on all heater products.
SJO Cord 194° F/ 90° C Available in 2 or 3 conductor. More rugged than HPN cord. Also available with molded plug. Optional on all heater products.

Types of Cartridge Heater Terminations

swaged in leadsSwaged in Leads

Swaged in leads are ideal for applications where there is a lot of movement or the leads must be bent sharp upon exiting the heater. Standard lead wire type is Duraflex wire, rated to 550 deg C. Other lead wire types are available.


crimped on leads

Crimped or Welded on Leads

Crimped on leads are generally used where the temperature at the end of the heater exceeds the maximum rated temperature of the lead wire. Since the connection between the leads and power pins is made outside the heater, the unheated length at the lead end of the heater is kept to a minimum. Crimped on leads are not recommended for applications where the leads must be bent sharply near the heater, or in applications where the leads will be subject to a lot of flexing. For flexing applications, a welded on connection would be better. The high temperature connectors are covered by 1- 1/2″ of 2500 volt silicone rubber coated fiberglass sleeving.


post terminalsPost Terminals

Also called screw terminals or stud terminals are used in applications where easy lead replacement is desirable. They work great with ring terminals or fork terminals. Post terminals are only available on 1/2″ diameter heaters and larger. Terminals are #6-32, other sizes are available.


right angle leadsRight Angle Leads

Right Angle Leads are ideal for applications where space is limited. leads are covered with silicon impregnated fiberglass sleeve where they exit the heater.

 


swaged in braid

Stainless Steel Braid

Provides excellent abrasion protection while allowing the leads to be bent in a tight radius. Because the braid is swaged in, it is extremely resistant to pulling out of the heater.


right angle braidRight Angle Stainless Steel Braid

Right angle stainless steel braid offers the same advantages as swaged in stainless steel braid, but allows use in tight spaces. When ordering, please specify the overall length.


swaged in conduitStainless Steel Flexible Conduit

Also known as armor or hose, Stainless Steel Flexible Conduit provides maximum lead protection from abrasion, but can not be bent quite as sharply as stainless steel braid. Conduit is swaged into the heater for maximum durability.


gala-convoluted-conduitConvoluted Conduit

Unlike standard conduit, convoluted conduit is sealed and provides complete water resistance at any temperature, while forming a positive seal against contamination entering the heater. It is available on standard 5/8″ and 3/4″ diameter cartridge heaters. In most cases, Convoluted Conduit is brazed directly to the heater. Convoluted Conduit is best used in applications where moisture or contamination is an issue. Located to the left, see close-up cross-section of convoluted conduit.


StrainReliefStrain Relief

This is used for applications that require the leads to flex repetitively