Flat tubular heaters boost efficiency for fryer technology

FROM fryers to griddles to ovens, heat is an important component in most foodservice applications. When it comes to the heat source for frying, not all heating elements are created equal. Electric fryer heaters can be segmented into two broad categories ?round tubular heaters and flat tubular heaters. When first introduced, fryer heaters were round tubular, but engineers found that a flat tubular design offered many benefits ?the most important being that the shape lifts the oil into the cook zone far better than round heaters. An innovation was born ?incorporating these efficient features.

Flat surface geometry.

Because of its design and geometry, flat tubular heaters will heat viscous fluids from ambient temperature faster than round tubular elements with the same wattage and at a lower sheath temperature. As the graphic shows, the round tubular has a much more erratic flow pattern due to the tubular's round shape, which causes a wider and less efficient flow of liquid around the heater surface. In contrast, the flow pattern around the flat tubular heater is streamlined; the flat surface has less restriction on the liquid as it moves up and past the heater sides. This efficient and faster flow pattern permits the liquid to move heat away from the sheath very quickly, resulting in the flat tubular heater's lower operating sheath temperature.

Greater buoyancy force.

This natural convection phenomenon partially depends on the ratio of a buoyancy force to the viscous force of the fluid being heated. The length of the heater sides mainly determines the buoyancy force or the flow of liquid up and across the heater surface. The side of a flat tubular heater is typically 25mm (1 inch), compared to the 10.9mm (0.43 inch) or less dimension of a round tubular element. The flat tubular heater's smaller edge and longer side creates a buoyancy force up to ten times greater than a round tubular heater depending on the material being heated.

Smaller dimension normal to flow.

Typically, a narrower dimension will give a smoother and faster liquid flow. For example, the round tubular's wide dimension, nearly a half-inch, inhibits the flow of liquid. It causes currents that disrupt the flow and the flow rate is somewhat slower. The flat tubular heater, on the other hand, has a much thinner dimension (5.97 mm), which reduces the drag forces on the liquid flowing past the heater. This allows the liquid to move past the flat heater faster than the round heater. The end result ?the flat tubular gets the heated liquid into the work zone faster than when using a round tubular. The flat tubular heater also has about a 50% greater surface area than a round tubular. This surface area design improvement is the key to lowering watt density for the same length heater or reducing the heater size while maintaining the same watt density.

Faster heat up

Flat surface technology provides faster heat up and recovery times than round tubular heaters. Their unique shape minimizes coking and oil degradation, and enhances the flow of the oil past the element's surface, helping to pull heat away from the heater sheath. Compacted magnesium oxide (MgO) insulation transfers heat away from resistance wire to sheath material and media more efficiently, shortening heat-up time. In addition, the heater lasts longer because it runs at a significantly lower sheath temperature than an equal watt density round tubular. This also prolongs the life of the oil, which shortens and reduces costs from frequent changing. If coking is a problem, it is an indication that the sheath temperature is too hot and is burning the oil. A flat tubular heater will provide a lower sheath temperature than a round tubular element, without reducing wattage or watt density. Coking is also reduced by the wiping action that occurs as the heated liquidAir Jordan XIII 13 Shoes