The Pressure in an Air Cannon

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.

The Pressure in an Air Cannon

A compressed air cannon may sound a little weird, but it’s surprising what a sudden pulse of air can do. For simply having fun, the AirZooka can blow a harmless ball of air up to 20 feet. Also for play is the Zero Blaster that launches 2-to-6-inch diameter non-toxic fog rings, which travel up to 14 feet. The fog allows the user and observers to see the toroid shape of the pressure pulse.

AirZooka Air Gun

Image Source: AirZooka on Amazon

The sudden release of a diaphragm allows pressure to build inside a chamber. With a restriction on the opposite end the pressure is increased according to Boyle’s law (P1 x V1 = P2 x V2).

One do-it yourself website for an air-powered cannon recommends attaching a bicycle pump or air compressor to build up pressure to 50-80 psi on a design that uses water pipe in a sealed chamber with a release valve. Depending on the design, air cannons are also used to launch potatoes, tennis balls and other stuff.

The world’s largest air cannon, built in the Czech Republic in collaboration with the TV show “Wonders of Nature,” can shoot air more than 300 feet. Its effectiveness was demonstrated by knocking down a wall of cardboard boxes. Smoke added to the pulse shows the toroid shape of the moving air.

Popular Mechanics Air Cannon DemoImage source: Popular Mechanics

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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 to Resuscitate

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 to Resuscitate

Unless you have had specific training, what you know about cardiopulmonary resuscitation (CPR) may be based on what you have seen on television or in a movie. You push on the unresponsive patient’s chest when they are not breathing. The compressions (pressure on the chest) take the place of a non-beating heart to keep blood flowing.

According to “Technique for chest compressions in adult CPR,” “Chest compressions have saved the lives of countless patients in cardiac arrest as they generate a small but critical amount of blood flow to the heart and brain.”

And, unlike other medical actions, chest compressions can be initiated by any healthcare provider without a physician’s order.

First aid response for CPR

First aid response for CPR
Image source: Science Photo Library.

For those not trained in CPR, the American Heart Association recommends hands-only CPR: uninterrupted chest compressions of 100 to 120 a minute until paramedics arrive. This means pushing straight down to compress the chest using your upper body weight (not just your arms) at least 2 inches (or about 5 centimeters) but not greater than 2.4 inches (about 6 centimeters). With the compression, the heart is squeezed and increases both the aortic and the right atrial pressures. Normal aortic pressures during systole (from the time the aortic valve opens until the peak aortic pressure), range from 80 mmHg to 120 mmHg. So how much pressure is required for the heart and for the brain in CPR? In a laboratory environment, researchers continue to explore the implications to improve the outcomes of CPR.

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Pop goes the Chip Bag

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.

Pop goes the Chip Bag

Transitioning from lower altitude to a higher altitude decreases the pressure on a sealed container. Normally this would be recognized by the bloated appearance of the product in a sealed bag and a rapid release of the pressurized air inside when the bag is opened.  However, if the bag’s seal is weak, the bag can explode with a surprisingly load pop, en route.

This occurred recently on a trip where the altitude changed from 1248 feet to 7500 feet. Taking the temperature difference into account, the external air pressure changed from 14.08 psi (97.8 kPa) to 11.25 psi (77.6 kPa). This resulted in the decrease in external pressure of 2.83 psi (20.2 kPa or 78.3 inches of water) – sufficient to explode the weak seal.

Surprisingly, this wasn’t the only time that a bag of the same brand of chips lost its seal during the same trip but previously the bag did not explode. Since several other brand of pretzels and other munchies did not experience a bag failure during many trips, it appears that a little product line pressure testing during packaging is in order to minimize a weak seal.

Air Pressure in a Chip Bag

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