To start a long cook on a pellet grill, the first step is to fill your pellet hopper with pellets. Grill companies claim long burn times, so once you do that, you should be all set, right? Not necessarily.
A common physics problem with pellet hoppers is the pellet level doesn’t stay uniform as the grill cooks. Instead, like digging on the beach, the pellets directly above the auger feed down leaving the pellets on the perimeter stuck at a higher level.
It also renders pellet level sensors less useful because the level isn’t uniform. The only current solution is to occasionally open your hopper, then use your hand to level everything out.
Hopper Shaker
According to a new patent filing from Weber Blackstone, they’re working on a solution to this problem. You can call it a shaker, vibrator, or agitator, but it helps with a pellet grill annoyance that’s always existed.
They have different options for this, but it revolves around mounting a motor with an eccentric weight on the end of it to shake the hopper and level out the pellets. They also suggest different control methods for the motor.
One is that it’s time based, so it just intermittently turns on. Another more advanced solution is to have it based on cooking temperature. You could use the feed rate calculation from the temp setting to also calculate the fluid dynamics of the mound of pellets and estimate how frequently it should turn on.
Final Touches
Attaching a motor to shake down the pellets is a good way to solve a common complaint, but just as if you give a mouse a cookie, it can come with other unintended consequences. Usually, vibration and mechanical components don’t play well together. Vibration can loosen hardware, make noise, and cause other mechanisms to not work correctly.
Weber Blackstone proposes potential solutions for this problem in the patent too. They talk about using a elastomers to isolate the motor and control the vibration in the pellet hopper. They also mention isolating the vibration between the pellet hopper and the cook chamber.