Body Pressures

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.

Body Pressures

Common  body pressure measurements include blood pressure  (80/120-mm (300 mm Hg, max)), respiratory pressure (4 kPa) and intraocular pressure for glaucoma testing (15 mm Hg). However, there are several other pressure measurements made at different body locations, most are made for diagnostic purposes. These include:

  • intra-bladder pressure (IBP) 12.3 ± 4.5 mmHg depending on body position to about 22 mmHg.
  • intragastric pressure, (IGP) 15.5 ± 3.5 mmHg vs 18.0 ± 8.7 mmHg
  • intra-abdominal pressure (IAP) typically less than 12 mmHg
  • anorectal manometry (ARM) 49 ± 3 mmHg resting to 238 ± 38 mmHg maximum squeeze range
  • vacuum (negative pressure) for an electric breast pump 0-270 mmHg

Similar to blood pressure and intraocular pressure, higher than normal readings identify potentially dangerous health situations. For example, an IAP equal to or above 12 mmHg is called Intra-abdominal Hypertension (IAH). Also, an IAP above 20 mmHg with evidence of organ dysfunction/failure defines abdominal compartment syndrome (ACS). Both of these higher than normal readings are known to cause significant morbidity and mortality among critically ill patients.

For healthy subjects, anal pressure is highly reproducible on separate days. ARM measurements in resting mode vary from 49 ± 3 to 58 ± 3 mmHg in women and from 49 ± 3 to 66 ± 6 mmHg in men. In contrast, maximum pressures range from 90 ± 9 to 159 ± 45 mm Hg in women and from 218 ± 18 to 238 ± 38 in men.

Oral to anal pressures vary depending on the location of the muscle cross sectional area (MCSA).

Oral to anal pressures vary depending on the location of the muscle cross sectional area (MCSA).
Source:  Physiology of the Gastrointestinal Tract .

Depending on the location, a significantly lower pressure can be a problem, too. For most people, blood pressure in the foot is similar to the blood pressure in the arm. A pressure drop of as little as 10% can indicate peripheral artery disease (PAD).

Not all pressures are positive measurements or made for diagnostic purposes. For example, an electric breast pump uses a vacuum (negative pressure) as high as 270 mmHg to collect milk for newborns.

For all of these body pressure measurements, highly accurate microelectromechanical systems (MEMS) pressure sensors can provide an essential tool for optimum healthcare.

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Pressure in the Salmon 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.

Pressure in the Salmon Cannon

Dams are helpful to control water flow in rivers but they pose a major problem for migratory fish like salmon. The dam restricts the salmon’s ability to swim upstream and spawn. In the United States alone, there are 85,000 dams. To solve the problem, Whooshh Innovations created its Fish Transport System, also called the Salmon Cannon.

With the Salmon Cannon, fish are either manually placed in a tube or slide in via a gravity slide below the dam. Then the soft tubing conforms to the size of the fish so a column of water does not have to be moved. Moving a column of water in, for example, a 1,700 feet project would require 0.433psi/ft x 1700ft = 736 psi.

In contrast, by conforming to the fish, they are essentially pushed through the system using an average of one to two psi. According to Whooshh CEO Vince Bryan III, “The system builds lower air pressure in front of the fish and more behind them with just a single blower motor, working just like a pneumatic tube at a bank.”

Based on independent studies that showed no scale loss, eye damage or other injuries, the amount of pressure safely transports fish from one area to another. The Whooshh tubes can handle a variety of fish sizes but generally transport fish between 2 and 34 pounds. In a typical system, the fish travel between 16 and 26 feet per second or about 18 miles per hour.

Whooshh Fish Cannon

Salmon fed into the Salmon Cannon below the dam transport through a tube to be safely returned to the water upstream, where they can continue their journey to spawn.
Source: The Guardian and Whooshh Innovations.

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Pressure and Driving by Propane

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 and Driving by Propane

Liquefied petroleum (LP) gas or propane is commonly used for heating but it can also be used for powering vehicles, especially those that have to operate indoors. Forklift manufacturers often offer a propane version in addition to diesel or electric versions. The propane version provides an alternative to diesel and is suitable for both inside and outside operation. A propane powered forklift can also be used in remote locations where additional tanks can be used to ensure that they work as long as required. When a tank is empty or near empty as indicated by its gage, the tank easy relatively easy to replace. Pressure in a propane tank can range between 100 and 200 psi or even higher, especially when the tank sits in the sun, and is not a good indicator of the precise content of the tank. So, a gage similar to ones used on consumer propane tanks is used to provide a rough pressure indication for the fuel level.

Propane tank in a forklift

 

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The Pressure in Tornadoes

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 Tornadoes

The pressure inside a tornado is less than the surrounding atmospheric pressure. That pressure differential causes flow into the tornado of objects such as cars, mobile homes, other structures and more (reference Dorothy and Toto). Since tornadoes travel and are only in a specific location for a short time, getting a pressure measurement inside the tornado is quite difficult, so the database is quite small. However, according to the National Oceanic and Atmospheric Administration (NOAA) of the U.S. Department of Commerce, “A barometer can start dropping many hours or even days in advance of a tornado if there is low pressure on a broad scale moving into the area.” Of the measurements that have been made in the U.S., the lowest recorded pressure difference is 194 millibars. While it could be damaged like anything else sucked into a tornado, an All Sensors digital output ADO Series barometric pressure sensor could provide the measurement for indicating the pressure drop usually indicative of changing weather conditions.

Tornado (National Center for Atmospheric Research (NCAR))

This tornado formed during a large thunderstorm in Wyoming.
Source: National Center for Atmospheric Research (NCAR).

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