Designing a laboratory pure water system, you also need to know these principles

      When designing a laboratory pure water system, the key points in the four subsystems that make up the pure water system should be considered first. To meet the water needs of the high-end analytical instruments used in laboratories today, a typical pure water system should include the following four parts:

1) Pure water preparation system 2) Pure water storage system 3) Pure water distribution system 4) Ultra pure water system

1. Pure water preparation system

The pure water preparation system uses tap water as the input water to prepare sufficient pure water that meets the specific water quality required by the laboratory, which is the starting point of the overall pure water system in the laboratory. The daily volume of pure water in the laboratory may vary from a few liters to several thousand liters. The first thing that should be considered in the design is to determine the daily water consumption of each user and each instrument, the quality of pure water required, and the regularity of water consumption. The pure water design department can then calculate the total daily water consumption and peak water consumption of the entire laboratory.

The quality of pure water required in the laboratory may also vary. It may be commonly used secondary water (analytical grade), tertiary water (experimental grade) or primary water (ultrapure water) for special application needs. The preparation of pure water can also adopt various purification techniques, such as reverse osmosis, ion exchange, continuous electrodeionization technology, distillation. Pure water quality standards and guidelines issued by many international standards organizations (ASTM, NCCLS, CAP, USP) will help us determine appropriate water quality.

The pure water control system is very important for the operation, maintenance and operation of the whole system. Therefore, the information displayed on the display panel of the pure water preparation system should be simple and clear, and the operation of the control panel should also be simple and quick. At the same time, in order to ensure the normal operation of the pure water preparation system and the quality of the produced water, not only the water quality of the produced water should be monitored, but also the quality of the influent water (tap water quality) should be monitored. Then the space occupied by the entire pure water preparation system and the cost of system operation should also be considered.

2. Pure water storage system

The second task of the overall laboratory pure water system design is to accurately evaluate the storage capacity of the pure water storage system. The pure water storage system should be able to balance the relationship between the pure water preparation system and the total daily water consumption and peak water consumption in the laboratory. Every laboratory has its own water usage rules, so the pure water storage system should not only meet the daily water consumption of customers, but also meet the peak water demand of the laboratory.

The storage system can act as a buffer between the daily peak water consumption, so that the pure water preparation system has enough time to produce the pure water required by the laboratory every day. At the same time, the pure water storage tank must be able to ensure that the water quality of pure water is stable and free from pollution. The material of the tank and many design details can affect the quality of the pure water stored in the tank. These design details include: closed design, tapered bottom, respirator, choice of filter elements in respirator and sanitary overflow. For example, an unsuitable respirator or filter element can cause airborne contaminants to enter the tank, thereby reducing the quality of pure water in the tank.

3. Pure water distribution system

The main purpose of the pure water distribution system is to deliver pure water to each water point through the distribution pump and the pure water distribution pipeline. In order to ensure the flow rate and pressure of pure water in the pipeline, laboratory pure water designers should accurately calculate the pressure loss caused by the pipeline system and equipment in the pipeline, so as to select the appropriate distribution pump.

4. Ultrapure water system

At the beginning of considering the ultrapure water system, the designer of the laboratory pure water system should clarify the purpose of ultrapure water. Generally speaking, pure water can already meet the water needs of most experiments. The quality of ultrapure water also varies according to different applications. Therefore, the purification method and water production volume of ultrapure water should be determined according to the use and amount of ultrapure water, so as to select the appropriate ultrapure water equipment. At the same time, the resistivity tester and total organic carbon monitoring equipment required for ultrapure water quality monitoring should also be considered. An important consideration for ultrapure water systems is the space required for installation of the ultrapure water system. The bench space occupied by the ultrapure water system should be minimized. The ease of operation and maintenance of the ultrapure water system and the operating cost are also issues that need to be considered.