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Four minute video demonstrating the technical aspects of the LintAlert®. Topics include three calibration attempts and advanced description of the firmware.
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LintAlert® Measuring Dryer Exhaust Transcript   Click Here to Close Transcript

Hi, I’m Rick Harpenau, the inventor of the LintAlert. Let me introduce you to LADI. LADI is our dryer demonstration instrument (Lint Alert Demonstration Instrument). We use this to test and demonstrate how the LintAlert deals with lint build up in a typical home environment.

To minimize its footprint, we will only be dealing with the core components of the dryer’s exhaust system. Here we’ve added a typical flex transition hose connected to an iris-style damper that we’ll use to simulate lint build up by closing down the aperture or choking the airflow.

Here, we’ve teed off the tubing to display the analog pressure levels with an industry standard magnehlic gauge that quickly indicates low air pressures up to two water column inches. In order for the LintAlert to accurately monitor the air pressure in the specific dryer’s exhaust duct, the device needs to be calibrated to your particular system at a like-new or very clean state.

In technical terms, a clean value must be recorded to memory in order to determine the proper interval proportions. These intervals are then progressively illuminated over time through the LED light bar.

Let’s start with demonstrating three calibration attempts of the LintAlert.

  1. Dryer Off
  2. Duct Clogged
  3. Most Likely State

First I’ll show that the LintAlert will not allow calibration if the dryer is off. Calibration is necessary and is achieved by holding the button in for five seconds. In this case, since the dryer is not running, the LED light bar illuminates indicators one and two which indicates that no pressure was found and will not allow a calibration.

Next, I’ll attempt a calibration with a simulated clogged duct. In this case (with back pressure at 1.10 water column inches) the LED light bar displays indicators four and five which indicate excessive back pressure and also will not allow a calibration.

In this final effort, we’ll attempt a calibration with a typical, or likely, home environment. Pressure levels in this group (typical dryer exhaust) range from .2 to .8 inches of water column pressure. Depending on what the LintAlert sensor finds, will determine what pressure intervals the microprocessor will use to illuminate the blockage indicator lights.

The lower the initial clean value pressure found, the larger the intervals between a graduation to the next warning level. And, on the flip side, the higher initial clean value pressure found, the smaller the intervals.

In this example, we successfully captured a clean value pressure of .5 water column inches, a pretty good mid-range or typical level. And, after a slight pause, we observe that the first green LED is illuminated, indicating to us that the dryer is on and about the same back pressure exists as when we initially calibrated. As I choke the airflow by slowly closing the aperture, you’ll observe in some unison that as the gauge needle rises, so does the blockage indicator light bar. If I turn off the dryer, the light bar goes out, as no pressure exists. Upon restarting the dryer, the LintAlert reveals that the same level of back pressure still exists in the system.

Over time, as lint continues to build up, so will the blockage indicator until the final stage which includes the combination of blinking lights and audible tone. The audible tone can be muted with a single push of the button. The blinking will remain as a reminder to asses the cause of the severe back pressure found.

Once the back pressure has been relieved, most likely by cleaning the exhaust conduit or termination hood, the LintAlert can be recalibrated. If the alarm state was accidental (perhaps the kids were interfering with the termination hood) simply power cycle the LintAlert to restore the original calibration level.

Remember to calibrate with no clothes in the drum, and with a clean lint screen.

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