Walking on Air (Pressure)

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.

Walking on Air (Pressure)

Perhaps more accurately it’s walking with air pressure. Re-released five years ago in 2016, the Nike Air Pressure sneaker initially appeared in 1989. They have a built-in pressure chamber and come with a pump for the user to apply the desired amount of pressure to achieve improved custom fit, comfort and stability. Nike also offered two other models with the pump system. However, they were not the only sneaker maker to offer a pressure system. In fact, they weren’t the first.

Nike Air Pressure Sneakers Nike Air Pressure Sneakers Pump

Nike Air Pressure sneakers and their pump
Source: https://sneakerbardetroit.com/nike-air-pressure-retro-release-date/

Using the pump to apply pressure to Nike Air Pressure sneakers

Using the pump to apply pressure to Nike Air Pressure sneakers
Source: https://sneakerbardetroit.com/nike-air-pressure-retro-release-date/

Exhibited earlier in 1989, the Reebok PUMP (which stands for performance under maximum pressure) was the first sneaker to have a totally contained inflation mechanism. Pressure was applied by a built-in ball (pump) in the tongue and released by a valve on the back of the shoe.

The air bladders were actually manufactured by a medical supply company in Boston, MA and then shipped to Korea for assembly into the shoes. This meant testing the bladders for initial quality in the US and then testing again after assembly in Korea to make sure the bladders were not punctured during the sewing process.

How much pressure is created? While the amount of pressure each individual applies will vary, applying more than 80 mmHg (1.5 psi) exceeds the normal diastolic (the lower number) blood pressure level but it can be uncomfortable at half this pressure.

In use, the bladder was quilted to control the amount of air that could be pumped into different locations around the foot. This meant that less air was applied to flexing locations and more to areas where gaps exist between the foot and the shoe, like between the heal and the ankle. This avoids the foot sliding and improves stability, especially under strenuous situations in basketball.

Reebok has also incorporated the technology into other products such as tennis, running, golf and aerobics shoes. More recently, Reeebok announced that its Pump Omni Zone II basketball sneaker would be available once again beginning March 5 and in a different color on May 21.

The Reebok Pump’s built-in orange pump

The Reebok Pump’s built-in orange pump
Source: Reebok

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Pressure for a Comfortable Ride

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.

Pressure for a Comfortable Ride

Compressing air in shock absorbers has been an effective way for automotive engineers to minimize the impact of bumps to a vehicle’s ride and take the harshness out of surprise potholes on poorly maintained or unimproved roads. One of the problems with the pneumatic design in these air suspension systems is the space requirement for the air cavity to be effective. Using activated carbon, a given amount of air space can produce at least twice the desired results. When force is applied to the load bearing surface of the activated carbon in a pressurized storage container, the activated carbon changes and limits how closely the air (or carbon dioxide, CO2) molecules can be compressed. As a result, the stiffness of the pressurized air increases more gradually and more linearly instead of exponentially, as it normally would without the activated carbon.

The activated carbon is not unlike the material used in some gas or liquid filter designs based on organic carbon. In this case, the material can be coal dust, sawdust or coconut shells. The exact consistency and additional processing can tune its response for a different adsorption rate in different designs and applications. In the air suspension application, the pressure in the container is around 0.5 to 5 MPa (72.5 to 725 psi).

This patented approach is already used in Audi A6 and A7 air suspension systems. It has applications in ride control and air suspension seats in numerous vehicles as well as in speakers and noise cancellation systems

A cup full of activated carbon | Source: Carbon Air Limited

At room temperature a cup full of activated carbon will contain about 6 times as much air as a cupful of air.
Source: Carbon Air Limited.

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Pressure on a Front-Loading Washing Machine Seal

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.

Pressure on a Front-Loading Washing Machine Seal

Unlike a top load washing machine, a front-load washer has a door boot, a flexible bellows-like seal, to prevents leaks. So, how much pressure can it withstand? Too much detergent can produce an excessive amount of soap bubbles or suds. Without answering the question, it turns out that the better response is you don’t want to find out, so use less detergent and avoid the problem.

High efficiency (HE) washing machines, like front loaders, are designed to use less HE detergent specially formulated with suds suppressors to prevent the machine from over-sudsing. In some washers, when the use of too much soap is detected by either a pressure switch (or sensor) or by the motor control unit sensing a suds-lock condition (by analyzing the current draw on the drive motor), a SUD error code flashes. Usually, just letting the machine rest to allow the bubbles to dissolve is the recommended response for the user. However, the error can also be caused by an obstructed drain that can require a repairman to resolve. The solution remains: use less detergent and avoid the problem.

Front-Load Washing MachineSource: Diego Cervo/Shutterstock

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Pressure Measurements for Comfort

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.

Pressure Measurements for Comfort

Pressure normally implies some level of discomfort. However, if the right amount of pressure is applied and not exceeded, a comfortable fit can be ensured. With this design goal in mind, companies have used pressure measurements to provide comfortable products from grip strength to earmuffs, headbands and headsets. In fact, one company makes test systems specifically for head applications.

Headsets and hearing protection need a comfortable fit so they can be worn for extended periods of time, especially in a work environment. The TactileHead pressure measurement and mapping system quantifies pressures exerted on the head from wearable head products such as these. Sensor measurements from the curved area around the ear of the mannequin head are compared to those from a sensor mounted to a flat plate on the other side of the head. With this controlled comparison, visualization and acquisition software can display the data and perform real-time analysis for evaluating the fit and comfort of an end product.

Full scale range for the pressure measurements is 2 Psi and the minimum detectable pressure for each sensor element is 28 Pa, or 0.004 psi. The system is calibrated in units of pressure (i.e., psi or N/cm²) and calculates force values (F=P*A) using the known area of the sensor element.

TactileHead customizable pressure measurement and mapping system

The TactileHead customizable pressure measurement and mapping system.
Image source: Pressure Profile Systems, Inc.

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