Technical articlesARTICLE

Provide a complete set of equipment and solutions for the laboratory

Index  >  News  >   Technical articles   >   Answers to common resistance problems of ultrapure water machine

Answers to common resistance problems of ultrapure water machine

Release time:2021-12-20    Views:1204

      The ultra pure water machine is roughly divided into four units: pretreatment, reverse osmosis, ultra purification and terminal ultrafiltration. Tap water first passes through the pretreatment unit to remove large particles, suspended solids and some organic matter in the water. During the use of ultrapure water machine, we often see or listen to 18.25m & omega Cm is the resistance value. What is the resistance value and why is it 18.25m & omega Cm, is there a higher value, such as 20.25m & omega Cm, let's discuss why the resistance value of ultrapure water machine usually does not exceed 18.25m & omega cm。


1. Understand the resistance value


To analyze the above problems, we must first have a certain understanding of the resistance value. Water contains anions and cations, and ions are conductive media. The measurement of water resistance can indirectly reflect the purity of water and the amount of ions contained. Generally, the lower the ion concentration in water, the lower the conductivity, the worse the conductivity, and the higher the resistance value; The higher the ion concentration in water, the higher the conductivity, the better the conductivity and the lower the resistance.


2. Why 18.25m & omega cm?


At 25 ℃, the dissociation constant of water is 1.01 * 10-14. This means that 1mol of water molecules will electrolyze 10-7 mol of H + and oh - respectively. Theoretically, water without any impurities (total salt concentration below 1ppb) will also have weak conductivity after electrolysis, and the conductivity is about 0.055-mu; S/cm。 The resistance value and conductivity are reciprocal to each other, and the corresponding resistance value is 18.25m & omega Cm (resistance value at ionization equilibrium of H + and oh - at 25 ℃). With simple design and excellent quality, YOUPU ultra pure water device provides you with laboratory grade pure water and ultra pure water in line with the national standard gb6682-2008.


3. Why not exceed 18.25m & omega cm?


It should be noted that 18.25m & omega Cm is the resistance value of ultrapure water machine under 25 ℃ and ideal state, which is the limit of ultrapure water purity under this state. In other words, there is no substance in water except water molecules, H + and oh -. Once there are impurities, the conductivity increases and the resistance value decreases. Therefore, the resistance value will not exceed 18.25m & omega; at 25 ℃ cm。


The above are the answers to some questions about the resistance of ultra pure water machine. I hope it can help you better understand the product.

WeChat official account

copyright © 2022 Nanjing Yipu Yida Technology Development Co., Ltd Al Rights Reseved    Record number:苏ICP备19073731号-1    Sitemap.xml    Manage login    technical support:Chemical Industry Instrument Website