Sandblasting 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.

Sandblasting Pressure

Removing paint, rust or an old finish from furniture and even polishing and finishing is less work with a sandblaster with the right abrasive and the right pressure. Small cabinet blasters often use pressures below 100 psi. In contrast, a heavy-duty sandblaster with a single-stage air compressor, air pressure over 120-150 psi is used to reduce the time involved. A pressure gauge is a common part of cabinet and portable sandblasters to obtain repeatable results.

Stark Tools 10 Gallon Air Sand Blaster

With a working pressure of 60 to 125 psi, this Stark Tools sandblaster has a 0 to 150 psi pressure gauge to obtain the desired operating pressure.
Image Courtesy of ToolPlanet.com

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Do you have a pressure sensing question? Let us know and we’ll address it in an upcoming blog.
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Critical Flight Measurements Using 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. In this blog we’ll be discussing critical flight measurements using pressure.

Critical Flight Measurements Using Pressure

Amplifying the low level signal from a higher pressure range sensor for a low pressure application can frequently lead to unacceptable noise problems in the application. This can occur if the sensor supplier performs this task as part of an amplified and signal-conditioned product offering or if the customer performs the amplification and signal conditioning. The limitation is inherently in the sensor die. Specially designed lower pressure range sensors, such as All Sensors DLVR Series mini digital output pressure sensors offer a solution to the noise problem.  The low mass, high-sensitivity die are less sensitive to errors due to vibration or changes in time, temperature and position.

All Sensors’ CoBeam2 TM die technology achieves a high level of pressure sensitivity without using boss structures and larger die topologies commonly used in microelectromechanical system (MEMS) designs. This design approach significantly reduces gravity and vibration sensitivities. As shown in Figure 1, CoBeam2 technology combines bonded strain gage sensor insight with state of the art MEMS processing.

31A

Figure 1 MEMS pressure sensor die using CoBeam2 technology

Figure 2 shows active dual-die compensation with electrical cross coupling of the sensors’ outputs and pneumatic cross coupling of the pressure used in the DLVR Series and other All Sensor products. By performing both electrical and pneumatic cross coupling, the signal strength is not reduced and the common mode error compensation is optimized. Some products use just the electrical cross coupling. Pressure Point 4: Dual Die Compensation for MEMS Pressure Sensors provides more details. Combined with CoBeam2 Technology, the amplified, digital output sensor reduces many errors associated with pressure measurements.

31B

(a)                                                                                      (b)

Figure 2  (a) Electrical cross coupling compensation of active die (Die 1) using a reference die (Die 2) and (b) pneumatic cross coupling compensation using fluidic channels in the pressure sensor package.

Drones, multicopters, quadcopters, small unmanned air vehicles (UAVs) and micro air vehicles (MAVs)  are not only the rage in modern flying craft, they are among the applications that can benefit from the improved sensor performance of a small form factor MEMS sensor.  Low pressure sensors such as the 1 inH2O DLVR-L01D up to the 10 inH2O DLVR-L10D can be used for measuring differential pressure on the wing in multiple locations to provide improved control and stability. Higher pressure ranges are also available.

Wind tunnel testing has traditionally used several pressure sensors on the wings of a test aircraft to provide a pressure-based estimation of the flow field above an airfoil. Recently, for increased control in drones, aerodynamics-based feedback using onboard active flow control schemes relies on a set of pressure measurements taken across the aircraft through pressure ports and through multi-hole probes. The aerodynamic feedback can be especially useful when switching control modes during various flight conditions.

Highly turbulent situations can also pose attitude control difficulties for fixed-wing MAVs. In Bioinspired Wing-Surface Pressure Sensing for Attitude Control of Micro Air Vehicles, researchers are investigating alternate technique using pressure sensors to solve this problem.

Other flight measurements can benefit from highly stable pressure sensors. For example, the DLV-015A DLV Series mini digital output absolute sensor can provide the barometer or altimeter readings in these same aircraft.

CoBeam2 is a trademark of All Sensors Corporation.

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)

Another PSI Sighting: Pressure Shows Up Everywhere

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.

Another PSI Sighting: Pressure Shows Up Everywhere

While I could be more sensitive than many other people, any indication of the need to measure and/or control pressure in everyday situations usually catches my attention. A recent observation was the number on a neighborhood fire hydrant – in big letters it stated 200 psi. It turns that this is a common working pressure design criteria for residential fire hydrants.

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Conducting flow and pressure testing measurements require a pitot gauge and a fire hydrant cap gauge. Pressure measurements on fire hydrants are performed primarily using analog gauges with a 0 to 300 psi range although digital instruments do exist with one digital gauge specifying 0.5% accuracy. Static pressure is the normal pressure existing on a system before the hydrant flow valve is opened. Local requirements vary but in one case, normal minimum water pressure in a distribution system cannot be below 35 psi when a fire hydrant is opened downstream and the minimum water pressure (residual psi) cannot be below 20 psi. Observed pressure requirements include: 75 psi for larger cities and 50 psi for smaller cities.

In addition to the pressure range and accuracy, environmental aspects for a fire hydrant pressure sensor include the ability to withstand the contact of water and possibly other materials. Properly specifying the “designed for” and other operating pressures and environmental requirements are just the beginning of getting the right pressure sensors for testing fire hydrants or measuring the pressure of any flowing/static liquid.

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)