PH meter, measuring medium: absorption tower slurry, power supply: 220VAC 50Hz, four wire system, output: 4-20mA, measurement range: 0-14, glass electrode, accuracy: ≤± 1%. Flange connection: GB/T9124.1-2019 DN80 PN1.0MPa, protection level: IP65, installation method: side mounted, insertion depth: 0.75 meters, sensor to instrument cable not less than 5 meters, with secondary display instrument, wall mounted or column mounted, replaceable online, equipped with plug-in installation brackets and other accessories. 、

What is pH meter? PH is the abbreviation of the Latin word "Pondus hydrogeni" (Pondus=pressure, pressure hydrogenum=hydrogen), used to measure the activity of hydrogen ions in a substance. This activity is directly related to the acidity, neutrality, and alkalinity of aqueous solutions. Water is chemically neutral, but it is not without ions, and even chemically pure water has trace amounts of dissociation: strictly speaking, hydrogen nuclei do not exist in a free state before hydration with water molecules.

H2O+ H2O=H3O+ + OHˉ， Due to the fact that the concentration of hydrated hydrogen ions (H3O+) is considered equivalent to the concentration of hydrogen ions (H+), the above equation can be simplified into the following commonly used form:

H2O=H+ + OHˉ

The positive hydrogen ion here is represented as "H+ion" or "hydrogen nucleus" in chemistry. Hydrated hydrogen nuclei are represented as "hydrated hydrogen ions". Negative hydroxide ions are called "hydroxide ions".

Using the law of mass action, an equilibrium constant can be found to represent the dissociation of pure water:

K=H3O+×OH------H2O

Due to the fact that only a very small amount of water is dissociated, the mass molar concentration of water is actually a constant, and there is an equilibrium constant K that can be used to calculate the ion product KW of water.

KW=K×H2O KW= H3O+·OH-=10-7·10-7=10-14mol/l(25℃)

That is to say, for one liter of pure water at 25 ℃, there are 10-7 moles of H3O+ions and 10-7 moles of OH - ions.

In neutral solution, the concentrations of hydrogen ion H+and hydroxide ion OH - are both 10-7mol/l. For example:

If there is an excess of hydrogen ions H+, the solution becomes acidic. Acid is a substance that can ionize hydrogen ions H+in aqueous solutions. Similarly, if OH - ions are ionized, the solution becomes alkaline. So, giving the H+value is sufficient to indicate the characteristics of the solution, whether it is acidic or alkaline. In order to avoid using this molecular concentration negative exponent for calculation, biologist Soernsen suggested in 1909 to replace this inconvenient value with a logarithm and define it as the "pH value". Mathematically, pH is defined as the commonly used logarithmic negative value of hydrogen ion concentration. That is, pH=- log [H+].