How to choose pure water and ultrapure water suitable for this unit

At present, the laboratories of universities, research institutes and other institutions basically use pure water and ultra-pure water machines instead of distilled water to make water, and the units above the municipal level in the eastern region have reached the level of popularization. Such as: environmental monitoring station, food and drug inspection office, disease control center, quality inspection office, agricultural soil and fertilizer station. Many enterprises' laboratories also use distilled water and ultra-pure water machines instead of distilled water to make water, especially in the eastern region and the central and western regions.

Compared with electric distilled water or buying water outside, the laboratory ultra-pure water machine provides more benefits and convenience. This has been recognized by the majority of chemical analysts, but the instrument is the basic equipment of the laboratory. Although many technicians are using ultra-pure water machines, their understanding of ultra-pure water machines is still not much, and there are often misunderstandings in the purchase. How to choose the ultra-pure water machine suitable for this unit, please refer to the following content, I hope to help you.

one. Water consumption

At present, the ultra-pure water machine on the market generally produces 5-20 liters/hour, and 20 liters or more is a non-standard model. The customer should select the specifications of the ultrapure water machine according to the actual water consumption, and generally follow the principle of 2 times relationship. If the water consumption is 10 liters/day, the machine with the specification of 20 liters/hour is selected. If the specification is too small, the consumption of the ultra-pure water machine will be very fast, and the selection specification is too large, which will result in waste. If the concentrated water consumption is large, you need to buy a larger pure water bucket, otherwise the water can't keep up.

two. Water quality

The standard water for national laboratories has three water types: first grade water, second grade water and third grade water. However, most laboratories can use two kinds of water quality, one is tertiary water, such as distilled water, used for cleaning glassware, etc. It is a first-grade water, mainly used for chemical analysis or precision instrument analysis such as liquid phase and atomic absorption. Customers should choose the grade of ultra-pure water machine according to the actual water quality requirements. The ultra-pure water machine with tap water as the water source has two (two water quality) outlets, one is pure water, that is, three-stage water; the other is first-grade water, that is, ultra-pure water (strictly speaking, first-grade water) The resistance is greater than 10 megohms, while the resistance of ultrapure water is greater than 18 megohms.

Most customers are not clear about their water quality requirements. Although the relevant national departments have various water quality standards, they do not have complete quantitative indicators for specific experimental projects or instrumental analysis. It is often found after purchasing ultra-pure water machines. not to standard. According to experience, you can follow the following purchasing principles and respond accordingly.

1 . Experimental content

Inorganic and organic experiments, inorganic experiments only need to have a water quality of more than 18 megohms, while organic experiments usually remove organic matter in water, so in addition to the resistance of more than 18 megohms, the total organic carbon is needed. If it is a biological experiment, it is necessary to remove bacteria from the water.

2 . Instrument type

Customers can choose ultra-pure water machines depending on the type of instrument used. The resistance of the liquid phase water is greater than 18 megohms; and the organic matter is removed; the atomic absorption, atomic fluorescence and environmental monitoring instruments use more than 18 megohms; the life science equipment such as PCR requires sterilization in addition to the resistance greater than 18 megohms. In addition to organic matter, in addition to heat.

3 . Current water source

If the customer's current water consumption is qualified, the source of the pure water can also be informed to the ultra-pure water machine manufacturer, and the technician will recommend the corresponding specification model according to the situation.

The above three principles are based on actual application experience and can be referenced, but the most accurate model selection is to provide detailed water quality parameters such as resistance, trace elements, bacteria, and total organic carbon levels.

three. Raw water quality

When purchasing ultra-pure water machine, customers must provide the manufacturer with the water quality of raw water, such as more sediment, high hardness, groundwater, etc. The process of ultra-pure water machine is determined according to the quality of raw water, sediment More, to add a pretreatment device, high hardness, to add a softening device, high salt content, to use a two-stage reverse osmosis process. If you choose an ultra-pure water machine that uses pure water as the water source, you only need to provide water quality requirements and water consumption.

four. How to use modular to choose pure water machine