TECHSTAR BLOG

Absolute Pressure Sensors in Varying Applications

Posted by TechStar on Nov 25, 2021 10:38:00 AM

Widely used in most industries, absolute pressure sensor applications provide specific measurements to meet both design and production needs. The steady growth of the global food packaging market size is one proof – where the main contributor is the consistent use of absolute pressure transmitters for their vacuum-sealed packaging.

This type of sensor has one of its sides exposed to a vacuum, while the other side receives pressure from liquid or gas. The sensor then sends an output signal to an electronic unit – an absolute pressure transmitter. This instrument takes absolute zero as its reference, providing an accurate reading without any external influence from factors such as elevation and temperature.

Absolute pressure transmitters, including all varieties, are essential in production environments requiring absolute pressure value.

Now the question is, where are absolute pressure sensors used?

As surprising as it sounds, various fields require this equipment – working exceptionally well in measuring pressure, gases, and flow rate in closed systems. As such, you will find pressure sensors used in numerous industries.

Automotive

Absolute pressure sensors also have various purposes in the automotive industry. Some companies use this instrument to develop highly accurate pressure sensors intended for harsh media applications. They integrate the sensors to help with external NTC temperature measurements. Other uses include direct injection and turbocharged engine applications.

Both petrol and diesel vehicles use manifold absolute pressure sensors, or MAP sensors, in measuring pressure in the engine manifold. They transmit the information to the engine's electronic control unit, or ECU, to determine the optimal combustion for ignition timing and air-fuel mix.

Another use of absolute pressure sensors in the automotive industry is securing vehicle safety, allowing the vehicle to sense side impacts and provide pedestrian protection.

Aviation

An altimeter is a vital component of many aircraft instruments because it is crucial to get precise pressure measurements as the aircraft changes altitude. Other instruments requiring absolute pressure values are manifold pressure gauges and rate-of-climb indicators. Interpreting these values using aneroid devices can calculate nearly all information to ensure proper aircraft operation.

Industrial

In industrial applications, absolute pressure sensors are often necessary for processes requiring partial vacuum, such as applications necessitating highly accurate measurements of vacuum in low-pressure ranges.

A great example is the meat packing industry, which requires specific quality of vacuum to enable maximum shelf life for various meats. Using a relative pressure sensor leads to fluctuations in measurement due to atmospheric changes, usually up to +/- 30mbar, and can result in inconsistencies with the expiry date. But with an absolute pressure sensor, manufacturers can ensure consistent pressure on every package.

Medical

One of the most obvious uses of absolute pressure sensors in the medical field is the vacuum sealing of equipment. They are part of high-grade vacuum pumps, ensuring medical products are free from bacteria and completely sealed upon transportation and before use.

You will find direct usage of equipment installed with absolute pressure sensors when delivering hyperbaric therapy. It involves increasing the air pressure in a sealed chamber where the patient is. The medical procedure treats decompression sickness experienced mainly by drivers and patients with burn injuries and skin grafts.

The sensors monitor pressure inside the chamber, including the amount of pressure applied during treatment. Absolute pressure sensors capable of measuring pressures of up to 100kPa play a significant role in the chamber's effectiveness.

Semiconductors

The semiconductor industry requires different measurement solutions such as pressure, vacuum, and temperature. In this field, it is critical to precisely control process parameters for reliable and accurate data measurement. Some of the specific processes and equipment utilizing absolute pressure sensors, together with other instruments of similar type, are as follows:

  • Load-lock vacuum pressure monitor and control of venting process

  • X-ray inspection

  • Leak detection

  • Wafer polishing

  • Crystal growth

  • Gas delivery and distribution systems

  • Cleanroom pressure control

  • E-beam lithography

  • Physical vapor deposition equipment

  • Hydrostatic level measurement

  • EUV lithography

  • DI water system supply pressure and temperature control

Weather Forecasting

Since absolute pressure sensors can take measurements independent of the current weather conditions and altitude, they are essential for weather forecasting. Compared to other sensors, this type notes the current ambient pressure relative to an enclosed vacuum fixed reference point – 0 bar ambient pressure.

Here are two examples of weather equipment utilizing absolute pressure sensors:

  • Barometer:

    This device can help predict weather changes by comparing the current ambient pressure with its variations.

  • Altimeter:

    Also known as altitude meter, this equipment measures atmospheric pressure and converts it to an altitude reading which references the mean sea level. Determining the atmospheric pressure requires the measurement from the altimeter and subtracting the altitude.

Absolute Pressure Sensor Applications Improves Human Lives

Aside from the ones mentioned above, absolute pressure sensors and transmitters have numerous other applications. No matter what industry you are in, the importance of this particular type of pressure sensor is evident. This versatile and reliable instrument will indeed continue to play a significant role in advancing human civilization.