Sleep on a Layer of Pressurized Air

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. In this blog we’ll discuss air pressure in mattresses and air beds.

Sleep on a Layer of Pressurized Air

Air mattresses and air beds use air pressure to provide an adjustable comfort level to users.  An air mattress can be easily stored in a small amount of space when it is deflated and brought back into service by “simply” inflating it.

For users that do not want to use lung power for the inflation process, how much pressure should be applied? Most manufacturers seem to recommend something around 1 psi maximum. For measurement purposes, a 5 psi pressure sensor can easily handle this range.

The pump can be built in or external to the mattress or bed. One inflator pump supplier offers a high-volume, low-pressure inflation with a pump pressure of 52 psi and pump volume of 3047 cubic feet/minute. With 1 psi as a max setting, the mattress can be filled quickly and its rating easily exceeded.

However, with this low level of internal pressure, barometric pressure can impact the feel and comfort level and even the life of an air mattress. One manufacturer recommends, “Partially deflate your mattress when leaving it inflated during the day, especially when in a car or tent on a hot day. (Barometric pressure and significant changes in weather and temperature will affect your air mattress’s inflation and possibly damage it.)

Air beds that have a dial setting where the user can determine his or her ideal comfort level may have an inappropriate setting if the weather changes significantly.

According to its website, “Comfortaire designed the first air bed over 28 years ago.” One of their beds even has a psi reading to determine the right comfort level.

With air pressure providing the desired comfort level, the old saying of “sleep tight” may need to be rephrased to “sleep at your ideal pressure.”

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Figure courtesy of Comfortaire.

What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
-Han Mai, Senior Marketing Specialist, All Sensors Corporation (hmai@allsensors.com)

The Pressure Impact from Higher to Lower Altitudes

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. In this blog we’ll discuss pressure and the difference in impact from high to lower altitudes.

The Pressure Impact from Higher to Lower Altitudes

If you have ever driven from a high altitude, say 5000’ above sea level to about 1000’, and you have a flexible sealed empty bottle in the car, at some point, you notice the creaking sound as the bottle collapses due to lower atmospheric pressure sealed inside and higher atmospheric pressure outside.  With the sound effect, the pressure increase on the sealed bottle taken from higher to lower altitude is quite noticeable. Obviously the pressure decreases (externally) during the reverse process and a gas tank (or other similar sealed vessel) taken to a higher altitude winds up visibly expanding.

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This is just one example of the impact of altitude pressure. Athletes performing at higher altitudes know that the altitude affects their performance, especially their endurance, since high altitude (HA) causes faster and deeper breathing. Altitude also affects sleep and cardiac output, so those accustomed to living at lower altitudes need to take appropriate precautions to adjust to the change. Training at higher altitudes can actually enhance the performance of athletes when they compete at lower altitudes.

Humans aren’t alone in their need to adjust to altitude. Internal combustion vehicles must adjust to altitude as well. When electronics was first used to adjust spark and fuel to reduce emissions and improve fuel economy, carmakers used barometric pressure sensors to adjust for altitude.

The pressure change from one altitude to another can be calculated by calculating the pressure for each altitude and then subtracting.  Air pressure above sea level is:

p = 101325 (1 – 2.25577 10-5 h)5.25588

where,

p = air pressure (in Pa)

h = altitude above sea level (in m)

What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
-Han Mai, Marketing Coordinator, All Sensors Corporation (hmai@allsensors.com)

Welcome to All Sensors Blog

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

Barometric or air pressure – either rising or falling – indicates a change in weather and is usually included in weather reports with temperature, rain or snowfall and wind measurements. While the temperature, rain and wind information is quickly verified by just going outside, the pressure measurement is a longer term issue. The absolute pressure measurement in inches of mercury for the U.S. is typically about 30.00 for a steady reading depending on height above sea level. The rate and amount of a falling barometer indicates how quickly a storm will occur and its severity. Barometric pressure change may be several days or only a few hours before the weather front. Accurate and precise pressure measurements need to consistently resolve a rather small pressure range since the pressure drop or rise from a steady barometer is usually within 00.20 inches of mercury.

What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
-Dan DeFalco, Marketing Manager, All Sensors Corporation (ddefalco@allsensors.com)