A limitation of current pellet grills on the market, is they only offer single zone cooking. Beyond that, there can also be dramatic temperature difference at different spots in the grill. The temperature gradient in the grill is a design byproduct and not something that can be controlled. Oklahoma Joe’s is looking to change that with a controllable, two zone pellet grill.
How it Works
According to a patent filing this week, Oklahoma Joe’s has been working on a way to create two zones in a pellet grill. With a setup similar to their Marshal Centerbox charcoal grill, the pellet grill design has two exhaust vents on the top of the grill.
In the patent they describe the possibility that the vents could be actuated by the controller to direct heat and smoke to the desired side of the grill.
The image above shows the flow of heat and smoke being directed. While the image looks like randomly scribbled lines, we’re assuming it was done with fluid dynamics modeling.
In the image, the exhaust vent on the right is opened more than the one on the left. This pulls the hot air that way, creating a cooler zone on the left side of the grill.
The grill controller knows how much to modulate the exhaust vents based on having two temperature sensors. It’s hard to make out in the picture above, but item 500 is a temperature sensor on both sides of the grill.
Benefits of Two Zone Control
There are two benefits from having two zone control on a pellet grill. The first is so that you can cook different food at two different temperatures at the same time. This is a big convenience when grilling on a pellet grill.
The second is the controller can adjust the zones to achieve better temperature uniformity across the grill. If you want a rack of ribs cooked at 265°, the controller can make the two zones much closer to 265°. That’s better that the variability that is seen on current pellet grills.
More Temperature Control
While a two zone setup is the main design feature of the grill in Oklahoma Joe’s patent, it does have one more innovation. It has the ability to control the volume of air going into the intake of the fan.
By controlling the amount of air that the fan pulls in prior to hitting the fire pot, it can give more temperature and smoke control to the burn. The patent includes different way to accomplish this, but one way is through an adjustable damper (item 1000 in the diagram). Like the exhaust vents, the damper could be manually or automatically controlled.