A Little Knowledge About Differential Pressure Sensor Before Buying It

Before discussing further about differential pressure sensors, it is better to understand what a pressure sensor is. In theory, pressure is an expression of the force exerted on a surface per unit area. A pressure sensor is a device that converts pressure into small electrical signals that are sent and displayed. The pressure sensor detects pressure and can determine the amount of pressure by measuring the electric charge. Usually, this tool is used to measure the pressure of liquids, air, and other gases. There are several pressure sensor devices that are often applied in the industrial sector; they are Gauge Pressure Sensors, Absolute Pressure Sensors, and Differential Pressure Sensors. The differential pressure sensor works by measuring two sensor differences (high and low) , the value of the pressure difference being the result of the Differential Sensor. It is usually used to measure the pressure level of a substance in a closed tube.

It is very important to understand some important points when choosing a differential pressure sensor. First of all you need to understand that a differential pressure sensor has the task of measuring the difference between two or more pressures level. You need accurate values as input to an industrial process feedback system. The value that appears on the sensor will be valuable data to ensure that the industrial process runs within the desired parameter range.

Thus, differential pressure sensors play an important role in every industrial process to avoid confusion about pressure ratings. The pressure rating describes the difference between pressure values such as gauge pressure or absolute pressure. Highly accurate pressure sensors are indispensable in pressure gauges to protect against extreme environments, such as in industrial of oil, gas and chemical applications; where in these areas the system will definitely experience vibration and corrosion.

Data sources from differential pressure sensors are useful for monitoring pressure in industrial piping systems. The measurement of differential pressure will be the basis for industrial measurements such as flow, altitude, density, viscosity, even for temperature measurement. Differential pressure is not affected by changes in fluid pressure, temperature pressure or other things such as environmental and weather influences. Good differential pressure sensors work by reading the differential pressure accurately, precise parameters, and various influencing factors and sending signals to represent the differential pressure displayed in other places such as the control room.

So, do you want to apply good pressure management to your industry? If yes, then you should use a Differential Pressure Sensor from Strainsense which can be used for various applications including filter blockage detection or HVAC.

Choosing the Best Pressure Sensor

While choosing the pressure sensor for your design, you have to look for some critical parameters, that are very important. Based on these parameters, you have to choose the available sensors. Of course, you have to look through the economical angle also.

These are the main parameters to look for –

Accuracy – First and foremost parameter is accuracy. What kind of accuracy you are looking for? Is your pressure very dynamic? Changing very fast? Or is the change slow? What is the rate of change? Do you have to continuously monitor the pressure and record the data or you have to measure it periodically? Based on your process, you have to decide, what kind of accuracy you are looking for. This will decide the type of sensors. Sensors are available with 0.5% accuracy to 0.1%, 0.25% and 0.05% accuracy. As the accuracy increases so as the prices.

Output – After you decide the accuracy, you have to look for the kind of output. These sensors come with Voltage and current output.

Sensors with voltage output, are generally used,where the sensors and measuring instrument or Data Acquisition system, both are near to each other. These sensors give out put in mV (millivolt-1000th of a volt) in the range of around 0 – 30 or 100 mv. Some sensors also have internal amplifier that offer output in the range of 0-5V or 0-10V. These kinds of sensors generally use strain gauges. The sensors with inbuilt amplifiers also provide internal zero and span adjustment facility. Though, because of these internal amplifiers, the frequency response is slow.

Sensors with current output are generally used when the distance between sensors and the measuring instrument or Data Acquisition system is more, like in big plants. As the output is in current form, they have high noise immunity. They also provide zero and span adjustment besides offering high frequency response.

Environment – The location of the sensors. This criteria is also very important in deciding the type of sensor. The operating environment will decide the mechanical structure of the sensor. If the sensor has to be used in harsh environment, it will have extra protection and because of these, it will cost more. While the sensors,which are used indoors,cost less.

Fitting – This is also an important factor. How you are going to fit the sensor? Does the sensor come with easy fitting couplings? Or you have to make a spatial mechanical arrangement for fitting? You have to consider all these factors before considering a particular type of pressure sensor which will fit into your design.

Pressure Sensors Work

Data on the possible applications of pressure transducers is also provided. There are many applications of these devices, especially in the industrial setting although they are also helpful in monitoring the tire pressure of automobiles. A frequent design for them, such as the Keller pressure sensors, is one that makes use of piezoresistive materials. These materials have the unusual characteristic whereby their resistance changes correspondingly with the force or pressure that is applied on them. These materials make up the key component of the sensors, which is the sensing diaphragm. This diaphragm is designed in such a way that its movement depends on the amount of pressure that is applied. However, it is also common for people to inquire on “how do pressure sensors work?,” because they realize that they are part of the systems for continuously monitoring the pressure of their car tires.

For those who are inquiring “how do pressure sensors work?” and are also interested on the mechanisms of the tire pressure sensor, this is a kind of technology that is designed for safety. It warns the driver in the event of a low tire pressure. This type of tire pressure monitoring system (TPMS) was mandated by the National Highway Traffic Safety Administration for all vehicles that are sold after 2008. There are two categories for TPMS and these are the direct and indirect systems. The direct TPMS has pressure transducers installed for every tire to constantly check on the tire pressure. However the indirect TMPS calculates the air pressure in the tire by measuring other variables, including the tires’ revolution per minute.

They can be of various kinds and include the differential, gauge, air, piezoresistive, digital, vacuum, and absolute pressure sensor. However, one of the most common designs uses piezoresistive materials, which means that the current is directly proportional to the pressure applied. The material is normally utilized is the semiconductor silicon. Several thin wafers of silicon are sandwiched in between protective materials.

So, how do pressure sensors work when they are specifically applied for ensuring that car tire pressure is within the proper range? Well, there are two basic components of the direct TPMS and these are the radio transmitter for sending the collected information to the vehicle’s on-board computer and the pressure sensor that is placed within the tire rim. Radio transmission is through the car antenna, which detects the signals and then routes them to the central monitoring system. However, for the indirect type of TPMS, the pressure transducers are not needed. The amount of pressure in the tires is estimated by determining the diameters of the tires. In turn, the diameters of the tires are calculated by using the rotational speed as input. If the on-board computer detects a somewhat faster rotational speed for one of the tires, it warns the driver that this particular tire has a lower air pressure because it has a smaller diameter.