How To Select A PH Measurement Device For Your Process //
The instruments designed to measure the pH level of a solution are simple in appearance. They're composed of electrodes and a readout that displays a numeric value. That value reflects the level of acidity or alkalinity in the measured substance.
Below, we'll briefly describe how pH levels are used in various applications. We'll also cover several criteria that should be taken into account when buying a pH meter.
What Is pH And Why Is It Important?
pH is a numeric measurement that reflects the acidity or alkalinity of a substance. A value between 1 and 14 is assigned, with 1 representing the highest level of acidity and 14 representing the highest level of alkalinity. A substance given a value of 7 is considered to be neutral. For example, lemon juice has a pH of 2.2; bleach has a pH of 13; and water has a pH of 7.
pH plays an important role in many industries, particularly those that are involved in the production or packaging of foodstuffs. The degree of acidity or alkalinity in a substance affects the function of living systems. In the case of people, it can have a significant influence on their health.
Common Applications For Which pH Is Measured
To appreciate the importance of pH measurement, it's helpful to consider the different ways it is used. One example is brewing. Beers tend to have a pH of 3.4 to 4.0. Brewers work low on the scale because a higher degree of acidity allows them to include stronger hops without the accompanying bitterness.
The coal industry measures the pH of surface runoff to control the degree of acidity before the runoff makes contact with watersheds. Surface runoff can have a pH as low as 2. That value must be raised - typically, with anhydrous ammonia - before it drains off.
Food processing manufacturers measure pH to control a number of qualities of the foodstuffs they produce. The acidity or alkalinity of an item can affect its flavor and shelf life.
Agricultural concerns measure pH to ensure the soil they use offers an hospitable environment for crops. Beneficial bacteria in the soil flourish with a slightly acidic balance. Select nutrients become unavailable to plants when the pH level is too high.
Ensure The Device Can Withstand The Temperature
In order for a pH measurement device to deliver accurate readings, it must be able to tolerate the temperature of the target environment. Many sensors are not designed to endure intense heat or cold. The glass that houses the sensor can break down, affecting the tool's accuracy.
Some instruments are built to withstand temperatures that reach 100 ºC and above. Others can tolerate temperatures that fall well below zero.
Balance Your Need For Durability And Accuracy
Accuracy is, of course, important when measuring pH levels for industrial processes. But the level of accuracy needed varies by application. For example, a laboratory may need to determine the pH of a target substance to +/- 0.001 pH units. A brewer may only need to measure within +/- 0.02 pH units.
Oftentimes, devices that are designed to provide a high degree of measurement precision are unsuitable for use in harsh environments. If you need an instrument that offers durability, expect to forgo a level of accuracy.
Choose A Device That Offers 2-Point Calibration
A pH measurement device must be calibrated to the target substance before it can deliver an accurate reading. Some instruments using single-point calibration. Others use 2-point calibration. The latter option is strongly advised for most industrial applications since it allows for better accuracy.
Selecting a pH measurement device doesn't have to be difficult or confusing. The key is to consider your process environment and identify the level of precision and accuracy you need in the readings. The service engineers and support staff at Applied Engineering can help you choose from among your options based on your process needs and budget.