Monthly Archives: May 2015

Pressure Sensing and the Internet of Things

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 the importance of sensing as a driving force for the Internet of Things.

Pressure Sensing and the Internet of Things

The Internet of Things (IoT) is certainly a hot topic these days. Sensing is among the driving forces for the IoT, Cloud, Smart Factories and many other popular terms for highly connected networks since the data from combinations of different types of sensors and distributed sensors provides entirely new functionality and performance capabilities. Pressure is among the sensing data required for the new levels of connectivity in consumer electronics, medical, industrial and other applications.

Among the added challenges for these advanced systems are: the need for digitized data, handling the added amount of information, decisions of local (sensor node/sensor hub) versus remote computing, added software/algorithms, and communicating the measured data to the internet.

For a supplier focused strictly on the pressure sensor measurement, this means enlisting and utilizing the support of expertise in other technology areas and referring customers to these experts.

Sources for IoT Design Support:

Embedded computing

Software/algorithms/sensor fusion

Wireless communications

Wired communications

Development platforms

All Sensors does not endorse or recommend these companies and organizations to the exclusion of other sources.

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)

May: National High Blood Pressure Education Month

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 the importance of high blood pressure and creating visibility for this important health issue.

May: National High Blood Pressure Education Month

Do not over inflate! For tires this means air pressure but for humans it means blood pressure. With high blood pressure, a person’s artery walls can fail and ultimately be the cause of death. With this in mind, the US Centers for Disease Control and Prevention (CDC) has designated May as National High Blood Pressure Education Month. The facts are:

  • Data from 2010 indicates that 1,000 deaths occurred each day in America due at least in part to high blood pressure.
  • In the US, about 1 of 3 adults or 67 million people has high blood pressure.

Target desirable readings are 120 over 80: a systolic (top) number of 120 millimeters of mercury (mmHg) and a diastolic (bottom) number of 80 mmHg. The top number is the pressure caused by the heart pumping blood and the bottom number is the value between beats. Higher values of 139 systolic and 80–89 diastolic indicate prehypertension. A person with a systolic reading of 140 or greater or diastolic value of 90 or greater has hypertension.

The mechanical sphygmomanometer remains one of the tools to measure blood pressure. However, MEMS pressure sensors provide accurate and easily automated measurements for digital pressure measurements and monitoring, especially in post-surgery and other critical situations. The American Heart Association has stated, “Accurate measurement of blood pressure is essential to classify individuals, to ascertain blood pressure–related risk, and to guide management.” While technique, cuff size, position, time of day and other factors are important for accurate measurements, accuracy starts at the level of the basic sensing element.

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)

Pressure Sensing and Improved HVAC Efficiency

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 look at pressure sensing and how it improves HVAC efficiency.

Pressure Sensing and Improved HVAC Efficiency

Clean air in heating, ventilating and air conditioning (HVAC) systems requires filtering to eliminate dust, pollen and other airborne contaminants in residential, commercial and industrial buildings for the health of occupants and equipment. Some locations such as clean rooms in semiconductor and other manufacturing operations as well as hospital operating rooms and research laboratories have very special requirements. Clean air depends on the filter’s initial efficiency and the pressure drop across it, which increases with usage. The pressure drop is also called the air filter resistance.

The National Air Filtration Association (NAFA) says, “Most large HVAC commercial grade systems are designed to handle pressure drops of one inch, possibly more, for the air filter resistance. Matching filter initial, final and average resistance to the system is critical for proper air filtration and air exchange rates. Also, providing pressure drop reading devices such as manometers or electronic pressure sensors is an absolute requirement.”

According to the Lawrence Berkeley National Laboratory (Berkeley Lab or LBL) Design Guide for Energy-Efficient Research Laboratories – Version 4.0, for HEPA filters, the “pressure drops can be as low as 0.1 inches water gage (w.g.) (24.9 Pa) and as high as 1.0 inches w.g. (249 Pa), with significant energy use impacts resulting from the nonlinear power use requirements of higher pressure drop filters.”

Filters are rated in static pressure at a specified cubic feet per minute (CFM) air flow. In 103 – Filtration Fundamentals, one company states that most heating /cooling systems in the residential and light commercial markets are designed to move 900 CFM to 2000 CFM at a total system static pressure of approximately 0.5″ to 0.7″ total pressure drop including the resistance through the ductwork and the filter.

With usage, the total pressure drop increases causing the filter to draw more power and increase the stress on the air handling equipment. The point where the pressure drop increases the electrical power consumption and overtakes the initial cost of the filter indicating that a filter change is required is called the optimal change-out point and is shown in Figure 1.

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Figure 1. The optimum final pressure drop across an air filter.

The equation used to determine the energy cost based on the final pressure drop is:

Energy Consumption (in kWh)= Q ∆P t / η 1000

Where:

Q = airflow (m3/sec)

ΔP = avg. pressure loss (Pa)

t = time in operation (hours)

η = fan efficiency

In the summary for pressure drop considerations for air filters, NAFA concludes, “Pressure drop reading devices are essential to determine optimum performance results and filter change-out frequency.”

Achieving the optimum performance leads to efficient filter operation and safe, clean air.

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)