Liquid pressure sensor is widely used for pressure measurement of various liquids. Like water or oils tank. IP68 waterproof.
Liquid pressure sensors also called a water level pressure sensor, or water pressure transducer. SI-10 liquid pressure sensor uses waterproof device to achieve IP68 waterproof rating. Like: water, oil pressure for pipe or tank. SI-10 liquid pressure sensor is a piezoresistive silicon pressure sensor. The main component of liquid pressure sensor is diffused silicon, with high stability. SI-10 liquid pressure sensor supports analog output, and 4-20mA, HART. For open tank, the liquid pressure sensor is easier to install than the differential pressure level measurement.
Features of SI-10 Liquid pressure sensor
- Adopt stainless steel integral components. High precision strain process. After highly reliable amplifier circuit and precise temperature compensation. With stable performance, good EMC electromagnetic compatibility and impact resistance.
- National standard 304 stainless steel seal welding. The structure is small and compact. Has good moisture resistance and excellent media compatibility.
- Adopt waterproof device to achieve IP68 waterproof rating.
- Integrated structure design, electrical part adopts fully sealed waterproof structure.
- Can be customized flat membrane waterproof pressure sensor. The diaphragm isolation technology is adopted, and the test head has no pressure hole. There is no clogging of viscous medium during the measurement. It is suitable for pressure measurement and control of viscous media such as chemical coatings, paints, mud, asphalt, crude oil and other harsh environments.
Specifications of Liquid Pressure Sensor
|Range:||-0.1 ～ 0, 1-5, 10, 20, 30-60, 80-150MPa (other ranges can be customized)|
|Comprehensive accuracy:||0.1% FS, 0.25% FS, 0.5% FS|
|Output signal:||4-20mA (2-wire system), 0-5 / 1-5 / 0-10V (3-wire system)|
|Power supply voltage:||24DCV (9 ～ 36DCV)|
|Medium temperature:||-20 ～ 75 ℃|
|Ambient temperature:||normal temperature (-20 ～ 65 ℃)|
|Load resistance:||current output type: maximum 800Ω; voltage output type: greater than 50KΩ|
|Insulation resistance:||greater than 2000MΩ (100VDC)|
|Long-term stability:||0.1% FS / year|
|Vibration effect:||In the mechanical vibration frequency 20Hz ～ 1000Hz, the output change is less than 0.1% FS|
|Electrical interface:||waterproof sealed outlet|
|Thread connection:||G1 / 4, M20 × 1.5 other threads can be customized.|
Applications of SI-10 Liquid pressure transducer
- Off-Highway Vehicles
- Natural Gas Equipment
- Semiconductor Processing
- Power Plants
How does a water pressure sensor work?
The core of the water pressure sensor is usually diffused silicon. The working principle of the water pressure sensor is that the pressure of the measured water pressure directly acts on the diaphragm of the sensor, so that the diaphragm produces a micro-displacement proportional to the water pressure. As a result, the resistance value of the sensor changes. Use an electronic circuit to detect this change. And convert and output a standard measurement signal corresponding to the pressure.
About the working principle of water pressure sensor, WIKA made a great introduction. Of course, if you need to know more about how the water pressure sensor works, please refer to Wikipedia: Pressure sensor
A pressure sensor may also be used to calculate the level of a fluid. This technique is commonly employed to measure the depth of a submerged body (such as a diver or submarine), or level of contents in a tank (such as in a water tower).
For most practical purposes, fluid level is directly proportional to pressure. In the case of fresh water where the contents are under atmospheric pressure, 1psi = 27.7 inH20 / 1Pa = 9.81 mmH20.
The basic equation for such a measurement is:
where P = pressure, ρ = density of the fluid, g = standard gravity, h = height of fluid column above pressure sensor
Liquid pressure sensor Calibration
If the transmitter is used for a period of time, it may cause a change in metering performance. There will be zero drift, and the measurement error will increase. Therefore, it is necessary to perform regular calibration.
The accuracy of the calibrator used for calibration should be more than 3 times the required calibration accuracy.
Use the pressure calibrator to input the standard pressure values of 0%, 25%, 50%, 75%, and 100% of the range to the transmitter in the forward and reverse directions.
Check whether the current output signal is within the allowable accuracy range. If it is out of tolerance, it needs to be adjusted.
The adjustment method is as follows (4 ~ 20mA output):
(1) Input a standard pressure of 4mA with a pressure calibrator. Adjust the ZERO (zero) potentiometer. Make the 4mA current output within the accuracy range;
(2) Input a standard pressure of 20mA with a pressure calibrator. Adjust the SPAN (range) potentiometer. Make the 20mA current output within the accuracy range;
(3) ZERO and SPAN will contain each other. Repeat steps (1) (2) until the current output of 4mA point and 20mA point meets the accuracy requirements at the same time. Then check whether the current output of 25%, 50% and 75% range points meet the accuracy requirements. The transmitter is qualified if it meets the requirements.
Differental pressure liquid level sensor
SMT3151LT differential pressure level transmitter is usually used to measure the liquid level in a closed container. The differential pressure level transmitter uses the differential pressure generated by the gravity of the liquid to measure the liquid level in the container.
The high-pressure side measuring tube is always filled with water due to steam condensation, keeping the pressure constant. The low-pressure side measuring tube forms a communication device with the container. The pressure changes with the liquid level in the container.
Sino-Inst offers overs 100 DP transmitters, for liquid level, pressure measurement. Our differential pressure (dp) level transmitters suit to measeure water and other liquid level.
A wide variety of DP level transmitters are available to you, such as SMT3151LT Differential pressure level transmitter.
Water pressure sensor
Water pressure sensors are usually used to measure the water level in the water tank or the rate of change of the water level. The sensor is mounted on top of an open tube submerged in the container.
As the water level rises, the air above the water in the tube is compressed, which increases the pressure on the sensor. An analog-to-digital converter (ADC) is used to convert the signal from the sensor to a digital value.
They can also be used to measure the pressure in running water pipes (for example, in a water supply system). It automatically determines whether it is necessary to start the pump to increase the flow rate.
They can be used to measure the depth of submerged objects. For example, in deep sea diving.
Of course, we can also calculate the liquid level based on water pressure. Or you can directly refer to our static pressure level transmitter.
Q & A
How does pressure sensor work?
What is the working principle of a pressure sensor?
A pressure sensor works by converting pressure into an analog electrical signal.
The demand for pressure measuring instruments increased during the steam age.
When pressure sensing technologies were first manufactured,
they were mechanical and used Bourdon tube gauges to move a needle,
and give a visual indication of pressure.
Nowadays we measure pressure electronically using pressure transducers and pressure switches.
What is a capacitive pressure sensor?
Capacitive pressure sensors typically use a thin diaphragm, as one plate of a capacitor.
The applied pressure causes the diaphragm to deflect and the capacitance to change.
You may like: Diaphragm Seal Pressure/ Differential Pressure Transmitters
This change may or may not be linear, and is typically on the order of several picofarads out of a total capacitance of 50-100 pF.
The change in capacitance may be used to control the frequency of an oscillator or to vary the coupling of an AC signal through a network.
The electronics for signal conditioning should be located close to the sensing element,
to prevent errors due to stray capacitance.
Read more about Capacitive pressure transducer [What is & How does it work]
What are the various types of sensors used to measure pressure?
Pressure measurements can be taken to determine a range of different values,
depending on whether the pressure is relative to the atmosphere,
vacuum conditions, or other measuring factors.
Pressure sensors are instruments that can be designed
and configured to detect pressure across these variables.
Absolute pressure sensors are intended to measure pressure relative to a vacuum,
and they are designed with a reference vacuum enclosed within the sensor itself.
These sensors can also measure atmospheric pressure.
Similarly, a gauge pressure sensor detects values relative to atmospheric pressure,
and part of the device is usually exposed to ambient conditions.
This device may be employed for blood pressure measurements.
For more information on the differences between the gauge and absolute pressure.
How to take off a high pressure sensor on thr liquid line?
Generally, the pressure sensor is installed behind the pressure valve. When you need to remove the pressure sensor, simply close the pressure valve.
When purchasing a pressure transmitter, the manufacturer will recommend configuring a valve block. Or according to the measurement situation, install the pressure guiding tube. This can facilitate the installation and disassembly of the pressure transmitter, while ensuring continuous flow of the pipeline.
How do you test a pressure sensor?
There are 3 commonly used detection methods for pressure sensors. Hope it can help you.
1. Pressure test. The method of detection is to power the sensor. Use your mouth to blow the air hole of the pressure sensor. Use the voltage file of a multimeter to detect the voltage change at the output of the sensor. If the relative sensitivity of the pressure sensor is large, this amount of change will be significant. If there is no change at all, you need to use a pneumatic source to apply pressure.
Through the above method, you can basically detect the condition of a sensor. If accurate testing is required, a standard pressure source is required. Give pressure to the sensor, and calibrate the sensor according to the pressure and the change of the output signal. And when conditions permit, the temperature detection of relevant parameters.
2. Zero point detection. Use the voltage range of the multimeter to detect the zero output of the sensor under no pressure. This output is generally a voltage of mV level. If it exceeds the technical specifications of the sensor, it means that the zero deviation of the sensor is out of range.
3. Detection of bridges. It mainly detects whether the circuit of the sensor is correct. It is generally a Wheatstone full-bridge circuit. Use the ohm file of the multimeter. Measure the impedance between the input terminals and the impedance between the output terminals. These two impedances are the input and output impedances of the pressure sensor. If the impedance is infinite, the bridge is disconnected. It means there is a problem with the sensor or the definition of the pin is not correct.
What is the difference between pressure switch and pressure transmitter?
When the pressure in the system is higher or lower than the rated safety pressure. The disc in the sensor moves instantaneously. Push the switch connector on or off by connecting the guide rod. When the pressure drops or rises to the rated recovery value, the disc resets instantly. The switch automatically resets. Or simply put, when the measured pressure exceeds the rated value, the free end of the elastic element is displaced. Push the switching element directly or after comparison. Change the on-off status of the switching element. To achieve the purpose of controlling the measured pressure. The elastic elements used in the pressure switch include single-turn spring tube, diaphragm, diaphragm box and bellows.
When the pressure signal acts on the sensor. The pressure sensor converts the pressure signal into an electrical signal. Amplified by differential amplifier and output amplifier. Finally, the V / A voltage and current are converted into a 4-20mA standard current output signal in linear correspondence with the measured medium (liquid) level pressure.
Pressure sensors for corrosive liquids and gases
Sino-Inst’s absolute pressure, gauge pressure and real gauge pressure and miniature pressure sensors are produced from the beginning. Can meet the most demanding tests and measurement specifications in some of the harshest environments. From general industrial process requirements to highly specialized sensors used in pressure hazardous locations.
Special products include micro-sized, ultra-micro-sized high-pressure high-temperature and flushing diaphragm models. To fit the space with narrow gaps.
Sino-Inst provides pressure and differential pressure sensors based on silicon or foil-based strain gauge technology. Very suitable for many types of applications in automotive, aerospace, chemical, semiconductor manufacturing and general industry.
All our pressure products are highly configurable. Can meet the unique requirements and environment of customers. On some pressure sensor models, intrinsically safe and explosion-proof options for use in hazardous locations are provided.
If you need special modifications or complete custom designs to meet your unique requirements, please feel free to contact us.
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