Pressure sensors are critical in keeping water systems safe.
In wastewater management and water treatment facilities, pressure measurement is employed in operations such as filtration, system pressure, flow and levels.
Pressure sensors utilized in this business must be able to deliver reliable readings in corrosive materials, effluents, solids, vibration and pulsation-prone situations.
They are utilized to monitor the system and offer vital information for proactive response to any abnormal conditions that may occur.
What is the pressure sensor?
a pressure sensor is an instrument that consists of a pressure-sensitive element that determines the actual pressure applied to the sensor (by various operating principles) and other components that turn this information into an output signal.
What are the applications of pressure sensors?
Because pressure sensors have a wide range of uses, there are many different types of sensors available with a wide range of features, whether for severe or corrosive environments, diagnostic supplies, or mobile devices.
When picking a pressure sensor, you must consider a wide range of technologies, packages, performance levels and features to meet multiple criteria for accurate pressure measurement, such as:
Measuring The pressure of the gas inside a tank, Measuring the level or volume of liquid contained by sensing the pressure at the vessel’s bottom and Monitoring or quantifying the movement of liquids or gases by measuring pressure variations between two points in a system.
Aeration basins, chemical feeds, chlorination, chlorine removal, distribution, flocculation, raw material inlets, mixing vessels, pumping stations, sedimentation operations and storage activities all use pressure sensors.
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Pressure sensors for leakage
Water is often delivered by a permanent subsurface network of pressurized pipes.
The water flow rate in pipelines can be controlled by altering the system pressure.
When new distribution pipelines are laid, their leak tightness is tested and documented before the pipes are put into service.
Employees can track pressure levels on-site using the manometer’s display screen throughout the test.
A large reduction in pressure during the test indicates a leaking pipeline, which can be repaired while the pipeline is still in production.
Pressure sensors for tanks
One of the most common methods for measuring the height of a fluid is to utilize a pressure sensor.
Any change in the liquid level above the pressure sensor is proportional to the change in pressure applied by the liquid head immediately above the pressure sensor.
A hydrostatic pressure sensor should be positioned at the lowest required measurement point, which could be an outlet or inlet, for example, at the bottom of the tank, to monitor the fluid level.
However, if there is a high flow rate, suction, or positive pressure at the outlet or inlet for a significant amount of time, this will also be registered by the hydrostatic pressure sensor, resulting in a false measurement of the liquid level.
The mechanism’s work of pressure sensors
An electronic pressure sensor measures the proportional change that occurs as a result of a physical reaction to applied pressure.
Changes in capacitance or ohmic resistance of a strain gauge or piezoelectric device, which are proportional to the magnitude of the deflection when pressure is applied, are common examples.
Important parameters like measurement range, environmental appropriateness, physical size, power requirements and the type of pressure measurement required will all affect engineers seeking an application-specific solution.
A pressure sensor, in a nutshell, turns pressure into a tiny electrical signal that is communicated and displayed.
Because of this, they’re also known as pressure transmitters. A 4 to 20 milliamps signal and a 0 to 5 Volts signal are two frequent signals.
The piezoelectric effect is used in most pressure sensors.
In response to stress, a material generates an electrical charge.
The most typical form of stress is pressure, although it may also come from twisting, bending, or vibration.
The pressure sensor measures the pressure and uses the electrical charge to calculate the amount of pressure.
Pressure sensors must be calibrated so that they can determine which voltage or milliamp (mA) output corresponds to which pressure.
This is a standard maintenance procedure that involves a basic “Zero” and “Span” (minimum and maximum) calibration.
Different types of pressure sensors
Since pressure sensors are used in many different applications, there are many types of sensors with distinct features, whether it’s for severe or corrosive environments, medical equipment, or mobile devices.
Gauge, absolute, and differential pressures are the three types of pressures that may be measured.
Pressure gauge
The pressure measured against the ambient air pressure is known as gauge pressure.
It can be positive or negative depending on whether the pressure is greater or lower than the atmospheric.
A gauge pressure sensor will have two ports, one for the reference pressure and the other for the pressure.
The difference in hydrostatic pressure and ambient air pressure is used to monitor liquid levels in a vented tank, which is a typical use for a gauge pressure sensor.
Pressure in absolute terms
Absolute pressure sensors will produce a value that is proportional to zero (a perfect vacuum).
Sensors will have a single port through which the medium will enter and apply pressure on the sensitive element, causing a positive variation of the flow proportional to the applied pressure.
This is helpful in applications that need the measurement of atmospheric pressure, such as height determination.
Because air pressure fluctuates with height, gauge pressure would not provide an accurate reading.
Absolute pressure sensors are also utilized in pressure measurement applications that will be used at different altitudes.
To improve tire performance, this sort of sensor is employed in tire pressure monitoring systems.
Pressure
Differential pressure sensors, like gauge sensors, measure the difference in pressure between two places.
However, the standard pressure in this situation is one of the system’s points, as established by the system designer.
Whichever is greater, the change in the differential output is positive or negative.
The pressure differential between the two domains determines the amount of the change.
Differential sensors, for example, are sometimes used to measure pressure differences on the opposite side of an item.
In HVAC applications, differential pressure sensors are often used to measure airflow.
References
[1] Pressure sensors: The design engineer’s guide, [online] Available at: https://www.avnet.com/wps/portal/abacus/solutions/technologies/sensors/pressure-sensors/
[2] What is a Pressure Sensor? [Online] Available at: https://www.hbm.com/en/7646/what-is-a-pressure-sensor/
[3] What is a Pressure Sensor? [Online] Available at: https://realpars.com/pressure-sensor/
[4] What is a Pressure Sensor? [online] Available at: https://www.variohm.com/news-media/technical-blog-archive/what-is-a-pressure-sensor-
[5] Pressure sensors for different media types, [online] Available at: https://www.avnet.com/wps/portal/abacus/solutions/technologies/sensors/pressure-sensors/media-types/water/
[6] Pressure Sensors, [online] Available at:
https://www.microsensorcorp.com/Product_Pressure-Sensor.html
