Tag Archives: air pressure

Progression of MEMS Pressure Sensing

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.

At Sensors Expo 2017, Jim Brownell, one of All Sensors’ sales managers, explained the progression of microelectromechanical system (MEMS) pressure sensing over the past 30+ years from All Sensors’ perspective.

Check out that interview here, courtesy of EE World Online’s Sensor Tips.

 

Comments/Questions?
Do you have a pressure sensing question? Let us know and we’ll address it in an upcoming blog.
Email us at info@allsensors.com

Sensing Pressure in Washing Machines

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 be discussing the pressure in washing machines.

Sensing Pressure in Washing Machines

Initially, timing was used to estimate the amount of water for various washing machine cleaning cycles. Today, many manufacturers sense the pressure developed in an air dome that is referenced to the water level and provides a much more accurate measurement. The air pressure level is measured either by a pressure switch or a pressure sensor with air providing isolation from the long term effects of operating a diaphragm in direct contact with water and other contamination.

The pressure switch can close and/or open contacts to provide an input to other circuitry. In contrast, the pressure sensor can provide either an analog or digital output to the washing machine control unit. Since the pressure sensor’s output directly results in a power control function such activating a pump or motor, in some manufacturers products, the pressure sensor is mounted in a Power Control and Pressure Sensing Module. The water level in most washing machines is well below 2 feet (0.87 psi), so a pressure sensor that can measure 1 psi would work in this application.

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Air pressure is sensed to measure water level in washing machines. Source: http://removeandreplace.com/wp-content/uploads/2013/12/washer-overfill.jpg

 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 in Hospital Isolation Rooms

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 be discussing pressure in hospitals.

The Pressure in Hospital Isolation Rooms

Infectious diseases and chronically ill patients require special air handling equipment in hospital isolation rooms. The isolation could dictate either positive or negative pressure in the room.

An isolation room at negative pressure has a lower pressure than that of adjacent areas. This keeps air from flowing out of the isolation room and into adjacent rooms or areas. In contrast, higher (positive) air pressure in the isolation room than in the adjacent corridor or anteroom prevents transmission from the outside environment to severely immunosuppressed patients.

Historically, the transmission of tuberculosis has been a concern for many years.  The Centers for Disease Control and Prevention (CDC) published and updated “Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Settings, 2005” a little over a decade ago and identified the need for a negative pressure of at least 0 .001 inch of water to prevent spreading the disease. More recently, Avian Bird Flu H5N1, another highly contagious disease, has raised the need for isolation and negative pressure control. A pandemic disaster or chemical warfare could further increase the number of negative pressure isolation rooms/wards required in a community.

Monitoring the room to outside differential pressure can be performed with manual techniques such as visually observing the direction of airflow using smoke tubes or with a pressure gauge. Both of these approaches require the person monitoring the room pressure to be at the room. With today’s lower pressure and cost-effective MEMS sensors, remote monitoring can easily be implemented so an expert (or experts) responsible for ensuring the positive pressure does not have to physically close to the patient’s room – and receives the warning of a problem in real-time.

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A pressure monitoring gauge is part of the isolation room equipment to monitor airflow. Source: http://biologicalcontrols.com/excbb.shtml

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)

Making Waves

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 be discussing artificial waves created by underwater gates and hydraulic pumps.

Making Waves

If you are not lucky enough to be within an easy drive from an ocean, a few companies make machines to generate waves, so you can surf where you live. The oldest location in the U.S., called Big Surf (1969), is in the middle of the desert in Arizona. With 15 underwater gates and hydraulic pumps, 50,000 gallons are released in 1.7 seconds creating 40-foot wide,  5-foot high waves that advance over a 2 ½ acre pool. The waves occur every minute.

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Surfing in the desert. Courtesy of Big Surf.

One wave machine manufacturer uses air pressure to create a variety of waves with reproducible point, beach and reef breaks. The largest waves generated by wave machines are about 3 meters (9.8 ft). In addition to pumping the water to heights of 9m (29 ft) or so, the pumping system also pushes the water through filters to keep the water clean.

Pressure sensors can be used at various points in the system to monitor the status of the process.

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)