Laundry equipment is very popular now, in our life everywhere, hotels, hotels, hospitals, laundry and other fields can be seen very industrial washing machine, so how to correctly use industrial washing machine still needs certain knowledge. Today we look at first, the water problems of industrial washing machine, not all of the water can be used for cleaning the oh, as you all know, water quality, divided into hard water and soft water. So in the washing is engineering with hard water, or use soft water good? I how can we detect water quality? 
 
Soap in hard water with calcium and magnesium ions generated difficult soluble calcium magnesium soap. Use of this characteristic, can simply identify soft water and hard water. 
 
To use soft water preparation transparent soap solution. The sample under test in a test tube, gently shake into good soap drops, static observation in a few minutes. If the generated bubble is not completely disappear, soap solution does not appear cloudy, can preliminary determination is soft water, otherwise known as hard water. True, accurate identification method should be adopted method for determination of the amount of calcium and magnesium. 
 
Methods to determine the amount of calcium and magnesium, also known as the EDTA titration method. Is in a certain pH value (pH = 10) and under the condition of complexometric titration with EDTA solution of calcium and magnesium ions. Measurement process, using then disodium magnesium, ammonium chloride and ammonia as the solution as a buffer solution, with chrome black T (also known as mordant black 11) as indicator, ED - TA disodium standard solution as the titration solution. 
 
When water quality determination, will first quantitative buffer solution to the sample under study, then quantitative winding black T indicator to the sample under study, the complex black T indicator react with the water calcium, magnesium, solution is purple or purple, the pH value shall be the 10 + / - 0.1 o to prevent settling, add the buffer and indicator, should immediately oscillation water samples, and under the condition of constant vibration wave, burette join EDTA disodium standard solution. Started titration, speed can be faster, the end of titration speed should be slower, and fully oscillation, every drop interval of 2 ~ 3 s. Solution of the color from purple or violet gradually to blue, in the last a little purple tones disappear, just a sky blue as the destination. Record the consumption of ml of EDTA disodium solution volume, again through the formula to calculate the amount of calcium, magnesium, water (c) : 
C = C1V1 / where V0 
Type of C1 - EDTA disodium solution concentration, tendency/L; 
V1, the volume of a solution of a titration cubits the consumption of EDTA disodium, mL 
Where V0 - water volume, ml. 
Amount of calcium and magnesium tendency for 1 / L is equivalent to 100 mg/L expressed in calcium carbonate hardness. 
EDTA titration method is the determination of calcium and magnesium in washing water amount of commonly used methods. For ease of washing water quality determination, be exempted from the operation of the various solution, Beijing innovative companies to develop the corresponding reagents. Reagent is equal to the buffer 1, no. 2 reagent is equal to the indicator, reagent no. 3 is equal to the standard EDTA disodium salt solution. Practical application, the first in the solution under test with 20 ml glass tube plug a scale to wash it twice, take water samples under test 10 mi, plus 3 1 drops shake, shake and add 5 2 drops, with 3 agent finally drops to solution from purple to blue for the end. The use of the 
The calculation results of reagents are as follows: 
 
Water hardness (1016 x) = 10 x 3 agent drips. 
 
According to the above analysis, we can understand that we are in the use of industrial washing machine. It is best to use hard water is better, oh.