Difference Between Distributed Wattage Heaters, Zoned Heaters, And Dual Voltage Heaters
TUTCO can provide a wide variety of heater options for many of our product lines. Some of those lesser known but very useful options are distributed wattage heaters, zoned heaters, and dual voltage heaters. They allow for better performance and better control over heaters so you can get the most out of them.
Distributed Wattage heaters are built to provide different amounts of heat over different sections of a heater while applying voltage to a single set of leadwires or screw terminals. A wattage distribution can be built into most types of heaters though it is most common in cartridge, band and some strip heaters. The purpose of the distributed wattage is usually to attain a better temperature profile (more even temperature) due to sections of a heater exhibiting greater heat loss than other sections.
Winding of resistance wire inside a heater is arranged so that it will produce different wattages over different lengths of the heater (in the case of cartridge heaters) or different wattages over different areas (in the case of band or strip heaters).
In the case of cartridge heaters, the ends are naturally cooler than the center of the heater, and applying the right wattage distribution to the heater can make the temperature more consistent over a longer length of the heater. The evenness of this temperature profile is most important for sealing applications where an even temperature is required across a sealing bar to provide a good melt across the material being sealed. The more even the temperature profile, the faster the sealing process can operate, which many customers want. There are some common wattage distributions that work in most cases. We call them 35-30-35 and 40-20-40 meaning that the heated length is split into three equal lengths and each section produces 35%, 30% and 35% or 40%, 20% and 40% of the total wattage. Those ‘hotter’ ends of the heater lead to a more even temperature profile. There are plenty of other distributions that a customer may want and they’ll specify the unique wattages and lengths that they’re looking for.
In the case of band heaters, a hole might be present in a heater to avoid a large bolt or some other obstruction. That obstruction might pull an excessive amount of heat from the heater thereby lowering its temperature near the hole. A distributed wattage can ‘fix’ that by putting more wattage around the hole, thereby producing a heater that generates heat with a more even temperature profile.
As the name states, a distributed wattage heater is a heater where wattage has been distributed or ‘moved around’ so the heater can provide the best performance for your situation. Zoned heaters are used when you want to be able to control different sections of a heater independently. There are a few different types of zoned heaters. They can be designed as cartridge heaters, most band heaters, and a few types of strip heaters.
In instances when there are two zones, there are typically 2 sets of leads (or screw terminals) where a set consists of two leads, so there are four leads in total. You could consider a band heater built with a flexible hinge option to be a zoned heater if it’s a continuous single heater yet has two sets of screw terminals or leads on either side of the gap. Those zones are operated independently in the same heater.
With cartridge heaters it can be a little tricker, but in most cases a heater with four leads can be produced and it gives you two zones to control independently, where the heating occurs at each end of the heater.
If you want a three-zone cartridge heater, that’s more of a challenge but still something we can offer. Due to the nature of the internal components of a cartridge heater we can only design it with 4 leads exiting at most. In that case, one of the leads would be a common lead, and the other three leads would be there for each zone. To control ‘Zone A’ in Figure 3, you would apply voltage from the Common Lead to the leadwire labeled ‘Zone A’. To operate Zones B and C, you would apply voltage between the Common Lead and the corresponding leadwire. All three zones can be operated simultaneously, and independently.
It should be noted that a three-phase power source cannot be used with this type of heater because you cannot adjust the voltage of each leg of a 3-phase power source, nor turn any of them off independently.
Zoned heaters give you the options to control separate sections of a heater as if they were their own separate heaters.
Dual Voltage heaters are built so that they can operate at one of two voltages and produce the same wattage over the entire length of the heater in both scenarios. A bit of clever wiring is how we build these types of heaters. This is helpful if a heater will be operated in the US and Europe and the customer needs to be able to account for that, by a simple wiring change. Dual voltage heaters (as either cartridge or band heaters) are built with 3 leadwires or screw terminals and voltage is applied either between only two of the connection points, ignoring the third, such as 1 and 3 in Figure 4 below or to that third terminal (2) and the other two terminals (1 and 3) connected together. It should be noted that dual voltage configurations are only possible when one voltage is exactly twice or exactly half of the other voltage. 110V/220V is a good combination, as is 230V/460V, but something like 110V/230V or 230V/480V is not possible.
For situations where you need to account for your applications being operated by possibly two different voltages, consider using a dual voltage heater.
As you can see there are several electric configuration options available that you may not be aware of or may have never taken advantage of. Consider the options available when you want to get the best performance out of your heaters.
