What is a pressure sensor? Pressure sensor classification and practical applications

1. What is a pressure sensor?

1. A pressure sensor (sometimes called a pressure transducer or pressure transmitter) is used to measure the pressure of a fluid (gas or liquid). Pressure is a representation of the force required to prevent a fluid from expanding and is usually stated in terms of force per unit area.
2. Pressure sensor is an electronic device that converts pressure signals into electronic signals. Through an integrated circuit, this device provides information about the pressure level being measured to the user. It is often used in measuring pressure in different environments or in systems that require continuous pressure monitoring.

2. Structure of pressure sensor

1. Pressure Media In: Where the environmental pressure is introduced into the sensor.
2. Process Connection Thread: The thread that secures the sensor to the system or device to which it is connected.
3. Sensing Diaphragm: A thin membrane that senses environmental pressure, converting the pressure into a measurable signal.
4. Capsule: Contains electronic components that sense pressure from the sensor membrane.
5. Connecting Pins: Serves to transmit signals from the sensor to the outside.
6. Conditioning Electronics: This part processes the signal from the sensor membrane and normalizes it before outputting it.
7. Housing: Protects the internal components of the sensor.
8. Cable: Used to connect the sensor to external devices, transmitting electrical signals.
9. O-Ring Seals: Provide sealing, preventing leakage of liquid or gas from the outside environment into the sensor.
10. Output: This section shows where the processed signal from the sensor is sent to subsequent devices or systems.

3. Pressure sensor classification

Absolute pressure sensor

1. Absolute pressure sensors measure pressure relative to a perfect vacuum (0 PSI or no pressure). Atmospheric pressure is 101.325 kPa (14.7 PSI) at sea level relative to a vacuum.
   Absolute pressure sensors are a type of pressure sensor designed to measure the pressure of a medium relative to an absolute vacuum. This is the actual pressure of the medium, independent of variations in the surrounding atmospheric pressure. This value is useful in applications that require high precision, such as in scientific instrumentation or in manufacturing industries where pressure must be strictly controlled.
2. Absolute pressure measurement works on the principle of comparing the pressure of the medium being measured to the absolute vacuum pressure. Absolute vacuum is considered the ‘0’ reference point – similar to how temperature is measured in Kelvin, where ‘0 K’ (zero Kelvin) is the lowest possible temperature.
3. For example, if an absolute pressure sensor measures 1 bar, it means that the pressure of that medium is 1 bar higher than the vacuum pressure. This method of measurement eliminates any influence from changes in atmospheric pressure, thus providing an accurate and consistent measurement, which is essential for applications such as scientific analysis and precision industrial processes.
4. Boyle's Law, which the description mentions, is a physical principle that states that the pressure of an ideal gas (with no change in mass) at a fixed volume and constant temperature will not change. This explains why measuring absolute pressure is important - it helps ensure that other variables such as volume and temperature are kept constant in order for the pressure to be measured accurately.

Absolute pressure sensors measure relative pressure to a sealed vacuum reference in a sealed chamber.

Pressure measurement sensor

1. A gauge pressure sensor is a type of pressure sensor designed to measure pressure relative to the current local atmospheric pressure. Unlike an absolute pressure sensor, a gauge pressure sensor does not measure the exact pressure value relative to an absolute vacuum but rather relative to the surrounding atmospheric pressure, making it suitable for many applications where the pressure difference is more important than the absolute pressure value.
2. In variable pressure environments such as on mountains or when the weather changes, atmospheric pressure can change significantly, and pressure gauge sensors provide accurate data on pressure differences without being affected by these changes. They are often used in medical systems such as vacuum pumps to ensure that the suction is not too strong or too weak, depending on the ambient pressure.
3. The construction of the pressure gauge sensor includes a connection port that can be connected to a pipe leading to the area where the pressure is to be measured and a vent that is open to the atmosphere. This vent is important because it allows the sensor to directly reference the surrounding atmospheric pressure to determine the differential pressure. In the design, you need to ensure that the vent is not blocked and is always exposed to the outside air to maintain measurement accuracy.

Pressure sensors measure pressure relative to local atmospheric pressure

Vacuum pressure sensor

1. Power supply: 24VDC
2. Pressure measurement range: from -1 to 0 bar
3. Output signal options: 4-20mA, 0-10V, 0-5V
4. Sensor housing material: Full stainless steel
5. Connection type: G1/2″ or G1/4″
6. Protection index: IP65
7. Operating temperature range: from -25 to +85 degrees C
8. Shock resistance: 40g in 60ms
9. Applicable environments: compressed air, water, and oil

1. Food and Pharmaceuticals: Helps create a vacuum environment to remove air, limit bacterial penetration, improve safety and ensure product hygiene.
2. Packaging and Packaging: Ensures the necessary vacuum during the packaging process to better preserve the product.
3. Cosmetics and Chemicals Industry: Used in the production process to ensure clean and safe products for consumers.

• Devices with integrated vacuum pressure sensors:

1. Vacuum Pumps: Used in factories to create the necessary vacuum environment.
2. Boiler Exhaust Fans: Used in industrial processes that require vacuum pressure.
3. Vacuum Pumps and Water Pumps: Important in maintaining pressure and flow in the system.

• Special applications:

1. In seafood processing industry: Negative pressure sensors are used in refrigeration systems to control internal pressure, ensuring efficient and stable freezing process.

Differential pressure sensor

1. Operating Principle: Differential pressure sensors measure the pressure difference between two points. They can operate on a variety of principles, such as diaphragm sensors, sphere sensors, or piezoelectric sensors.
2. Accuracy: The accuracy of the sensor is very high, typically ranging from ±0.25% to ±1% of the measuring range. This accuracy is important in applications that require high precision measurements, such as in the pharmaceutical or food processing industries.
3. Measuring range: The measuring range of the sensor can vary widely, depending on the specific application and system requirements. It can measure from a few Pascals in HVAC applications, to hundreds of bars in heavy industrial applications.
4. Material: The material used to make the sensor must be compatible with the working environment. Commonly used materials include stainless steel, titanium, and engineering plastics, suitable for highly corrosive environments or strict hygiene requirements.
5. Output signal: The sensor output signal can be an analog signal (e.g. 4-20 mA or 0-10 V) or a digital signal, suitable for integration into automatic control systems and remote monitoring.
6. Compatibility: The sensor must be compatible with other components in the system to ensure efficient and safe operation. It also needs to comply with relevant safety and environmental standards.
7. Applications: Differential pressure sensors are widely used in industries such as oil and gas, chemical, medical, water and wastewater treatment, HVAC and many others.

Sealed pressure sensor

1. High Accuracy: Sealed pressure sensors are typically very accurate, making them suitable for applications in the medical industry, precision manufacturing, and harsh environments.
2. Sealed Design: Environmental resistance is an important feature of this type of sensor, protecting against the ingress of water, dust, and other liquids, ensuring the sensor operates reliably in harsh conditions.
3. Wide Applications: Sealed pressure sensors can be used in applications such as altimeter, barometric pressure measurement, HVAC systems, in the automotive industry for measuring oil or fuel pressure, and in the oil and gas industry.
4. Sensor Technology: Many sealed pressure sensors use MEMS (Micro-Electro-Mechanical Systems) technology, allowing them to be compact and responsive while maintaining high accuracy.
5. Output signal: Similar to other types of pressure sensors, sealed pressure sensors can provide an analog or digital output signal, usually a voltage, current, or coded digital signal.

4. Some important factors to consider when selecting a pressure sensor

Pressure environment

Ambient temperature pressure

Operating environment

Pressure range to be measured

Accuracy

Electrical output signal

Process connection type

Electrical connection type

1. Media: Hydraulic oil.
2. Sensor selection: A sensor with a flat diaphragm should be selected to avoid clogging by impurities that may be present in the hydraulic oil.

1. Operating temperature: Hydraulic oil can heat up to 80°C during operation.
2. Sensor selection: Sensors that can withstand high temperatures, up to at least 100°C to ensure safety and reliability.

1. Conditions: The factory has a dusty, high vibration environment.
2. Sensor selection: The sensor is well protected against dust and is resistant to vibration.

1. Pressure range: From 0 to 300 bar.
2. Sensor selection: The sensor has a suitable measurement range and a backup pressure resistance of up to 450 bar to avoid damage due to sudden pressure increases.

1. Required accuracy: Error not exceeding 1%.
2. Sensor selection: High-precision sensor, suitable for the exact technical requirements of the system.

1. Signal: The control system uses a voltage signal.
2. Sensor selection: Sensors with voltage output signals (e.g. 0-10 V).

1. Connection type: Thread.
2. Sensor selection: Sensors with threaded connections to fit pipes and valves in the system.

1. Electrical connection: Cable.

1. Sensor selection: Sensors with cable connections for easy installation and maintenance.

5. Pressure sensor application

1. Pressure sensors are widely used in a variety of applications. When used directly to measure pressure, applications include weather instruments, aerospace and defense, research and development, the automotive industry, and many other types of machinery or equipment that have a pressure function. They can be used in hydraulic systems, water depth measurement, pneumatics, marine, wastewater, gas, medical, food and beverage processing, tank level/content measurement, HVAC systems, agricultural equipment, aerospace, and chemicals.
2. Other notable versions include high temperature, three-in-one, ATEX certified, hygienic and adjustable in-situ pressure sensors. Other popular variants include ceramic pressure capsules, low-cost strain grate sensors, water level/depth transmitters and differential pressure transmitters (wet/wet and dry for air/gas).

1. Here, the pressure sensor uses the Venturi Effect to measure the flow. The differential pressure is measured between two sections of the Venturi tube having different orifices. The pressure difference between these two sections is proportional to the flow rate through the Venturi tube. Usually a low capacity pressure sensor is required because the pressure difference is relatively small.

1. This is useful in commercial and military aircraft, missiles, satellites, and weather instruments. These types of applications all use the relationship between pressure change and altitude.
2. By understanding the applications of pressure sensors in different fields, you can select and use them more effectively for your specific needs.

6. Top 5 popular pressure sensor brands on the market

Autonics Pressure Sensor

1. High Accuracy: Suitable for applications requiring high reliability.
2. Wide Pressure Range: Accurate measurement in a variety of environments and conditions.
3. Anti-interference: Stable design, withstands harsh environmental conditions.
4. Easy installation: Compact design, easy integration into automated systems.
5. Long life: Reduced maintenance costs thanks to durable materials.

Buy genuine Autonics pressure sensors at: Amazen Industrial Electrical Equipment

1. Rectangular design and compact size, there are analog voltage and analog current models that can be directly connected to HMI, PC, and PLC of many different brands,..
2. Rated pressure range

1. Compact design:

1. Analog output: voltage (1-5VDC), current (DC 4-20mA)

1. Power supply: 12-24 VDC ±10%

1. Measures the pressure of gas, liquid or oil (except substances that can corrode 304/316L stainless steel)
2. Automatic adjustment function: When the initial pressure changes, the external input will adjust the pressure level to match this change (only applicable to models with automatic hold/adjustment function)
3. Hold function: maintains the current display value or control output value
4. Forced output control mode for device inspection and maintenance
5. Easy wiring and maintenance with 1-touch plug
6. Zero point adjustment function, peak value monitoring function, oscillation prevention function.

1. High-precision pressure sensor
2. Bright red LED (character height: 9.5mm)
3. High resolution: negative pressure 0.1kPa / standard pressure 0.1kPa, 1 kPa / mixed pressure 0.2kPa
4. Pressure unit conversion function
   - Vacuum pressure, Mixed pressure: kPa, kgf/cm², bar, psi, mmHg, mmH₂O, inHg
   - Standard pressure: kPa, kgf/cm², bar, psi
5. Various output modes: Hysteresis mode, Automatic sensitivity setting mode, Independent 2-point output mode, Comparison output mode
6. Vibration prevention function (response time: 2.5, 5, 100, 500ms)
7. Analog output (1-5VDC)
8. Zero point adjustment function
9. High and low value display
10. Built-in circuit protection against reverse power polarity, overcurrent

Huba pressure sensor

1. High quality: Huba Control sensors are manufactured to Swiss quality standards, ensuring high accuracy and reliability.
2. Diverse models: Huba Control offers a wide range of pressure sensor models for various applications, from low pressure to high pressure.
3. Advanced sensor technology: Using MEMS and ceramic sensor technology allows for more accurate measurements and faster response.
4. Flexible Applications: The sensors can be used in many industries, including harsh environments such as the chemical industry or marine.
5. Easy integration: The design is compatible with many control and monitoring systems, making installation and integration into automation systems easier.

See more information about Huba pressure sensors at: https://amazen.com.vn/cam-bien/huba.html

1. Meidum: Liquids and gases
2. Pressure range: 0 ... 10 — 100 mbar
3. Output: proportional. 10 ... 70%
4. Accuracy: < 0.3% of speed
5. Electrical connection: RAST 2.5 connector
6. Pressure connection: Ø 6.2 mm tube connector

1. Meidum: Refrigerant
2. Pressure range: -1 ... 7 – 60 bar
3. Output: proportional. 10 ... 90%
   0 ... 5V
   1 ...6V
   0 ... 10V
   4 ... 20mA
4. Accuracy: < 0.5% of speed
5. Electrical connection: DIN EN 175301-803-A or C connector
6. M12x1 cable 1.5 m
7. Pressure connection: Male or female thread

1. Medium: Liquids, gases and refrigerants
2. Pressure range: -1 ... 9 bar / 0 ... 2.5 – 1000 bar
3. Output: 0 ... 5 V

1. Accuracy: typ. < 0.3% FS
2. Electrical connection: Swift connector

1. Pressure connection: Inside thread or outside thread

TPC Pressure Sensor

1. High Brightness LCD Display: Provides clear, easy-to-read display even in low light conditions.
2. High Resolution (1/1000): Enables precise measurements with high accuracy.
3. Versatile Unit Conversion:
   • Composite Pressure: Can be displayed in kPa, kg/cm², bar, psi, mmHg, mmH2O, and inHg.
   • Static Pressure: Can be displayed in kPa, kg/cm², bar, psi, and MPa.
4. Various output functions:
   Pre-independent output mode: Comparison between two pressure values
   Delay output mode: Allows flexible response time setting.
5. Interference suppression function:
   Response time adjustment: Response time can be selected from 2.5 msec to 500 msec, minimizing the influence of interference.
6. Analog output (1~5VDC): Built-in analog signal output for demanding applications.
7. Protection function: Overcurrent and reverse voltage protection (ensure safety and service life of the device).
8. Zero adjustment function: Allows resetting the zero point for more accurate measurement.
9. Peak and bottom display: Helps to monitor the largest and smallest fluctuations of pressure.
10. Auxiliary battery compatible: Capable of working with an auxiliary battery, enhancing portability.

Where to buy cheap TPC pressure sensors: Amazen Industrial Electrical Equipment

Georgin Pressure Sensor

1. Pressure measuring range: 0 to 600 bar.
2. Overpressure resistance: Up to 200% of measured value.
3. Material: Connection pins and sensor membrane made of 316L stainless steel, increasing corrosion resistance and durability
4. Protection standard: IP65, dust and water resistant
5. Size: Compact, convenient for installation
6. Response time: Less than 4ms
7. Output signal: 4-20mA, 0-5V, 0-10V
8. Error: 1%
9. Origin: France​​​​​​​

Keller Pressure Sensor

1. Sensor membrane material: Using 316L stainless steel, allowing the sensor to operate effectively with 99.9% of different types of fluids, superior to other materials such as Ceramic.
2. Isolated output signal: The analog signals of the sensor are highly accurate and are designed to be isolated against interference, very suitable for applications using inverters where signals are often susceptible to interference.
3. Sensor housing material: Made entirely of 316 stainless steel, increasing durability and the ability to withstand harsh environmental conditions.
4. Goods status: Available in large quantities at the warehouse in Ho Chi Minh City, ensuring a variety of measuring scales and quickly meeting delivery schedules.
5. Price: Due to being manufactured entirely in Switzerland and imported directly in large quantities, Keller agents in Vietnam can offer competitive prices compared to products in the same segment from Germany or Switzerland.

7. Conclude