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

Power Washing or Pressure Washing?

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.

Power Washing or Pressure Washing?

Washing your car or hosing off the driveway typically uses about 40 to 50 PSI of pressure. In contrast, the pressure in a power washer or a pressure washer can be 40 to 200 times higher. While these terms are sometimes used interchangeably, a power washer uses a high pressurized stream of hot water and pressure washer almost always uses high pressure cold or normal water. The operating pressure of the pressure washer varies considerably depending on the level of the machine.

Commercial grade pressure washers, can be from 1000 to 4000 PSI with pressures below 2000 PSI more common in more affordable units. For example, one electric pressure washer operates at 1600 PSI (max) and delivers 1.2 GPM (max). Another example, operates at maximum volume of 1.6 GPM and a maximum pressure of 2000 PSI.

Semi-pro pressure washers have a significantly higher power output, PSI and GPM ratings than commercial washers with 1800 to 3000 PSI and 1.6 to 4 GPM being typical ranges. These units typically use only cold water. Unlike an electric unit that operates at 1800 to 2000 PSI max, a gas type unit can deliver 2500 to 4000 PSI.

At the high end, professional pressure washers are rated at 3000 to 8000 PSI and 2 to 8 GPM and deliver cold and hot water. Pressure regulation is common in these units that allows decreasing the pressure for mixing with detergent, increasing the pressure for removing mold from brick or decreasing the pressure to sanitize commercial kitchens with hot water. Common applications of profession pressure washers include car washes, kitchens, meat packing facilities and more.

All Sensors CPA 602 Series media isolated ceramic amplified pressure sensors can address pressure measurements in pressure and power washing systems up to 6000 PSI.

Vortexx Pressure Washer

 

This professional pressure washer operates at 4000 PSI and 4 GPM max.
Source: Vortexx.

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

Turbocharged Performance

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.

Turbocharged Performance

Vehicle manufacturers offer turbochargers and use smaller displacement and/or fewer cylinder engines to optimize power vs. fuel economy trade-offs. For example, instead of 6-cylinder engine, a manufacturer can offer a 4-cylinder with a turbocharger. When the turbo is operating, customers get the performance and power benefits of a 6-cylinder engine and when the turbo is off, they get the fuel economy of a 4-cylinder.

Since, an engine’s power is proportional to the amount of air and fuel delivered to the cylinders, the turbocharger increases the inlet manifold pressure and density so the cylinders get a greater mass of air during each intake stroke. The pressure ratio (πC) versus air flow determines the performance of the turbocharger.

πC = P2C/ P1C

Where:

P2c = Compressor discharge absolute pressure

P1c = Compressor inlet absolute pressure

The typical increase in intake manifold pressure (boost pressure) is around 12 psi gauge. Calculations for P1c must account for intercooler pressure drop and P2c must account for air filter pressure drop. With a sea level atmospheric pressure of 14.7 psi, intercooler pressure drop of 2 psi and air filter pressure drop of 0.5 psi:

πC = (12 + 2 + 14.7) / (14.7 -.5) = 2.02

The absolute pressure sensors used in an engine control system are typically rated at 200 kPa (2 atmospheres or 29.4 psia).

55

Pressure ratio vs. corrected airflow plot for a Garrett GT3582R compressor.

Source: EPI Inc.

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

Communicating Using Nasal 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.

Communicating Using Nasal Pressure

Blink once for yes, twice for no. This technique is frequently used in movies, TV and real life to communicate with a person who is severely injured. It is also used to communicate with “spirits” and even as a secret code for perfectly healthy individuals. In either case, the communications are always limited to yes or no. With the help of pressure sensors, the ability to communicate and even control objects could improve dramatically.

In the report, “Sniffing enables communication and environmental control for the severely disabled,” researchers investigated and confirmed a premise that in addition to eye control, sniffing may remain unimpaired following a severe injury. This is of interest especially for quadriplegic and “locked-in syndrome” patients. Locked-in syndrome patients have intact cognition but are completely paralyzed, so communicating using eye blinks is a harsh reality.

For their analysis, researchers needed to measure nasal pressure and convert it into electrical signals; they needed a pressure sensor that could provide very accurate, high resolution linear measurements of low pressure signals. For their sniff controller, the researchers used All Sensors’ 1-INCH D1-4V-MINI  Miniature Amplified Output pressure sensor. With this sensor, common mode errors and output offset errors due to change in temperature, stability to warm-up, stability to long time period, and position sensitivity are significantly reduced.

To confirm their theory and the possible capabilities of nasal pressure variations, measurements on healthy subjects were made using a mouse, joystick and the sniff controller. Figure 1 shows the approach, data and sensor used for the measurements. With the theory confirmed on healthy individuals, the next step was testing on the target test group.

54A

 

(A)54B

(B)

 

Figure 1. Data from sniff controller measurements (a) using the 1-INCH D1-4V-MINI low pressure sensor (b) show excellent results compared to well-established mouse and joystick control techniques.

Using precise nasal pressure measurements, the researchers’ test results show that sniffing allowed completely paralyzed locked-in participants to write text and quadriplegic participants to write text and even maneuver an electric wheelchair. They also determined that the sniff controller can be used independently of respiration, so even artificially-respirated individuals can benefit from its implementation in end products.

In addition to its use in those end products, the 1-INCH D1-4V-MINI can provide the required accuracy for many other respiratory measurements and other low pressure measurements in medical and other applications.

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