Method and apparatus for measuring concentration of dissolved gas in liquid, and apparatus for producing nitrogen gas dissolved water
A technology of dissolved gas and measurement method, applied in the direction of degassing by filtering liquid, separation method, chemical instrument and method, etc., can solve problems such as impossible measurement
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Embodiment 1
[0055] Embodiment 1 (degassing degree evaluation of preliminary degassed water)
[0056] According to the flow rate of 16.7L / min, the dissolved oxygen concentration of 8.0mg / L of ultrapure water without degassing treatment is passed into the degassing membrane module "4-inch module, trade name: ヘキセル, produced by ヘキスト・セラニ-ズ" In ", a vacuum pump is used for membrane degassing. Part of the pre-deaerated water was passed at 1.67 L / min into a 2.5-inch module having the same structure as the above-mentioned deaeration membrane module, and the gas phase was sealed to measure the degree of vacuum. The area A of the gas permeable membrane of the 2.5-inch module is 14000cm 2 , the flow rate B of the tested liquid is 1670cm 3 / min, A / B is 8.4min / cm. In addition, the volume of the gas phase chamber of the 2.5-inch module is 150cm 3 , the capacity of the liquid phase chamber is 400cm 3 , the capacity of the gas phase chamber is 0.375 times that of the liquid phase chamber.
[0057] U...
Embodiment 2
[0060] Embodiment 2 (degassing degree evaluation of preliminary degassed water)
[0061]The same operation as in Example 1 was carried out by using ultrapure water in which the dissolved oxygen concentration was 5 μg / L and the dissolved nitrogen was in a saturated state, which was subjected to denitrogenation treatment. It is difficult to precisely measure the dissolved oxygen concentration of pre-deaerated water, but the vacuum degree of the gas phase of the 2.5-inch module is -0.09 MPa, the same as in Example 1. From this result, it was found that the total value of the dissolved gas concentration was reduced to 1 / 10 of that before degassing. Use a dissolved nitrogen meter to measure the dissolved nitrogen concentration before and after degassing. At this time, compared with 18.6 mg / L before degassing, it is 1.9 mg / L after degassing, which is the same as the dissolved gas concentration calculated by vacuum degree. Changes are well consistent.
[0062] However, when the dis...
Embodiment 3
[0064] Embodiment 3 (evaluation of ultrapure water)
[0065] In recent years, in order to prevent the deterioration of water quality, the ultrapure water used in the electronics industry factory is often cleaned with nitrogen in the tank. Even when the concentration of dissolved oxygen in ultrapure water is strictly controlled, in many cases, the concentration of dissolved nitrogen is left to its own accord. When the produced ultrapure water is used quickly, the dissolved amount of nitrogen gas is small, but when the time of keeping it in the tank becomes longer, the dissolved amount of nitrogen gas increases.
[0066] In the electronics industry factory, the ultrapure water through membrane degassing is stored in the tank through nitrogen cleaning, in the ultrapure water system, the same 2.5-inch assembly as in Example 1 is set, and the measurement maintains the equilibrium state with the ultrapure water The vacuum degree of the gas phase, and the dissolved nitrogen meter is...
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