Heated ultrapure water production system

Abstract

A heated ultrapure water production system includes: an ultrapure water production unit that comprises a primary pure water production apparatus and a secondary pure water production apparatus 1; a heated ultrapure water supply pipe 21 that supplies ultrapure water W1 from the ultrapure water production unit to a second point of use 25; and a remaining-heat device 22 and a heating device 23 that heat the ultrapure water W1. The heated ultrapure water production system has connected thereto a water sampling line 31 that branches off from the heated ultrapure water supply pipe 21. The heated ultrapure water supply pipe 21 is made of a polymer material that contains a halogen element in a repeating unit. The water sampling line 31 is made of: a polymer material that contains no halogen element in a repeating unit; or a metal material. With such a heated ultrapure water production system, it is possible to accurately evaluate the water quality of heated ultrapure water, and it is possible to provide a heated ultrapure water production system that comprises a water sampling line made of inexpensive and easily available material for which a stable supply can be expected.

Description

Hot ultrapure water production system

[0001] The present invention relates to a hot ultrapure water production system, and more particularly to a water sampling line for a hot ultrapure water production system equipped with a hot ultrapure water sampling line.

[0002] Ultrapure water used for semiconductor cleaning is produced by treating raw water (industrial water, city water, well water, etc.) in an ultra-high temperature ultrapure water production system that has a pretreatment system, a primary pure water production unit, and a subsystem (secondary pure water production unit).

[0003] The pretreatment system, consisting of coagulation, pressurized flotation (sedimentation), and filtration (membrane filtration) devices, removes suspended solids and colloidal substances from the raw water. This process also allows for the removal of high-molecular-weight organic compounds and hydrophobic organic compounds.

[0004] The primary pure water system includes a heat exchanger, a reverse osmosis membrane treatment system (RO system), an ion exchange system (mixed bed type or 4-bed 5-column type, etc.), and a degasser. The primary pure water production system removes ions and organic components from the raw water. Note that the viscosity of water decreases and the permeability of the RO membrane improves as the temperature of the water increases. For this reason, a heat exchanger is installed before the reverse osmosis membrane treatment system to heat the water so that the temperature of the water supplied to the reverse osmosis membrane treatment system is above a predetermined temperature. The reverse osmosis membrane treatment system removes salts, as well as ionic components and TOC. The ion exchange system removes salts and inorganic carbon (IC), as well as TOC components that are adsorbed or ion-exchanged by ion exchange resin. The degasser removes inorganic carbon (IC) and dissolved oxygen.

[0005] The primary pure water produced by the primary pure water production system is sent to a subsystem. This subsystem includes a sub-tank (pure water tank), a low-pressure ultraviolet oxidation system (UV system), an ion exchange system, etc. In the low-pressure ultraviolet oxidation system, 185 nm ultraviolet light emitted from a low-pressure ultraviolet lamp converts TOC into organic acids and then CO2. ２ It decomposes to this extent. Organic matter and CO2 are produced by the decomposition. ２ These are removed by a subsequent ion exchange device.

[0006] A warm ultrapure water production system produces warm ultrapure water by raising the temperature of ultrapure water produced by such an ultrapure water production device to 60-75°C using heating means such as a heat exchanger, and then filtering it through an ultrafiltration membrane (UF membrane).

[0007] In a hot ultrapure water production system, the hot ultrapure water flowing through the piping is at a high temperature, so utmost care is required during water sampling for accurate water quality evaluation of the hot ultrapure water. Patent Document 1 describes a method for sampling hot ultrapure water for such water quality evaluation, which avoids the generation of elutes by cooling the hot ultrapure water before sampling, thereby enabling accurate water quality evaluation of the hot ultrapure water. Patent Document 1 also describes using tubes made of materials that do not substantially contaminate ultrapure water, such as fluororesin or PEEK resin.

[0008] Japanese Patent Application Publication No. 11-64184

[0009] However, these fluororesins and PEEK resins are relatively expensive components, and using them to construct a water sampling line increases the cost of the line. Furthermore, fluororesins have the problem of being difficult to obtain due to the risk of unstable supply. In addition, since the hot ultrapure water supplied by the hot ultrapure water production system is at a high temperature of 60-75°C, utmost care is required during water sampling for accurate water quality assessment of the hot ultrapure water.

[0010] Because the ultrapure water circulating through these pipes is at a high temperature, utmost care is required during water sampling for accurate water quality assessment. However, there is a need to construct a water sampling line using readily available components that can accurately assess the water quality of ultrapure water, is inexpensive, and can be supplied stably, but such a system has not existed until now.

[0011] This invention has been made in view of the above problems, and aims to provide a hot ultrapure water production system that can accurately evaluate the water quality of hot ultrapure water and is equipped with a water sampling line made of readily available components that are inexpensive and can be expected to provide a stable supply.

[0012] In view of the above objectives, the present invention provides a hot ultrapure water production system comprising: an ultrapure water production unit equipped with a primary pure water production device and a secondary pure water production device; a hot ultrapure water supply pipe for supplying ultrapure water from the ultrapure water production unit to a point of use; a heating means provided in the hot ultrapure water supply pipe; and a water sampling line branching from the hot ultrapure water supply pipe, wherein the hot ultrapure water supply pipe is made of a polymer material containing halogen elements in repeating units, and the water sampling line is made of a polymer material or metal material that does not contain halogen elements in repeating units (Invention 1).

[0013] According to this invention (Invention 1), by forming a hot ultrapure water supply pipe with a polymer material containing halogen elements such as fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) as repeating units, while forming a water sampling line with a polymer material that does not contain halogen elements as repeating units, such as an olefin resin, or a metal material, it is possible to suppress the addition of elution from the water sampling line to the elution from the hot ultrapure water production supply pipe, thereby enabling accurate water quality evaluation of the hot ultrapure water produced by the hot ultrapure water production system. Furthermore, since olefin resins and metal materials are less expensive than polymer materials containing halogen elements as repeating units, cost reductions for constructing the water sampling line can be expected, and they are readily available, making them suitable as components for the water sampling line. In particular, when using metal materials, there is no permeation of gases, so it is possible to collect water without inhaling dissolved gases or volatile organic compounds from the surroundings, even in environments with poor surrounding conditions.

[0014] In the above invention (Invention 1), it is preferable that the water intake line is composed of two or more of the following: a nipple, a valve, a fitting, a pipe, or a tube (Invention 2).

[0015] According to this invention (Invention 2), a suitable water sampling line can be configured depending on the configuration of the apparatus.

[0016] In the above invention (Invention 2), it is preferable that the water sampling line has a heat exchanger for cooling (Invention 3). In the above invention (Invention 3), it is preferable that the heat exchanger for cooling is a metal shell-and-tube type or plate type heat exchanger (Invention 4). In the above invention (Invention 4), it is preferable that the heat exchanger for cooling is capable of cooling the temperature of the warm ultrapure water collected in the water sampling line to 40°C or below (Invention 5).

[0017] According to these inventions (inventions 3 to 5), by effectively lowering the temperature of the warm ultrapure water, the generation of elutes from nipples, valves, fittings, pipes, or tubes that constitute the water sampling line can be further avoided, and accurate water quality evaluation of the warm ultrapure water can be performed.

[0018] In the above inventions (inventions 3 to 5), it is preferable to have one or more bottle sampling mechanisms, online concentration devices, and introduction mechanisms to online monitors located downstream of the heat exchanger for cooling the water sampling line (invention 6).

[0019] According to this invention (Invention 6), the water collection line can be effectively utilized by arranging elements that have functions according to the purpose of water collection.

[0020] The present invention provides a thermal ultrapure water production system in which the thermal ultrapure water supply piping is made of a polymer material containing halogen elements in repeating units, and the water sampling line is made of a polymer material or metal material that does not contain halogen elements in repeating units, thus enabling accurate water quality evaluation of the thermal ultrapure water production system. Furthermore, it is possible to reduce the cost of constructing the water sampling line, and the materials are readily available, making them suitable components for the water sampling line. In particular, when metal materials are used, there is no permeation of dissolved gases, so it is possible to collect water without inhaling dissolved gases or volatile organic compounds from the surroundings, even in environments with poor surrounding conditions.

[0021] This is a flow chart showing a thermal ultrapure water production system according to one embodiment of the present invention.

[0022] The following description of the thermal ultrapure water production system and the method for producing thermal ultrapure water using the present invention will be explained with reference to the attached drawings.

[0023] (Hot Ultrapure Water Production System) The hot ultrapure water production system of the present invention comprises an ultrapure water production unit equipped with a primary pure water production device and a secondary pure water production device, a hot ultrapure water supply pipe that supplies ultrapure water from the ultrapure water production unit to a point of use, and a water sampling line that branches off from the hot ultrapure water supply pipe and has heating means for heating the ultrapure water.

[0024] Hereinafter, an embodiment of the thermal ultrapure water production system of the present invention will be described with reference to the attached drawings. In this embodiment, the primary pure water production apparatus is not particularly limited, and a general-purpose, known primary pure water production apparatus can be applied with normal control, so this will be omitted.

[0025] The thermal ultrapure water production system of this embodiment has a configuration as shown in Figure 1, for example. In Figure 1, the thermal ultrapure water production system includes, as a secondary pure water device (subsystem) 1, a sub-tank 2 for storing primary pure water W supplied from the primary pure water device, a water supply pipe 2A as an ultrapure water supply pipe, a water supply pump 3 whose output can be controlled by an inverter, a heat exchanger 4, an ultraviolet oxidation device 5, a hydrogen peroxide decomposition device 6 filled with a platinum catalyst, a membrane degasser 7, a booster pump 8 whose output can be controlled by an inverter, a non-regenerative ion exchange resin device 9, and an ultrafiltration membrane (UF membrane) 10. An ultrapure water supply pipe 11 is connected downstream of the ultrafiltration membrane 10, and this ultrapure water supply pipe 11 is connected to a first use point 12 that uses ultrapure water W1 at room temperature, and the unused ultrapure water W1 at this first use point 12 is returned to the sub-tank 2 from the return pipe 13.

[0026] Meanwhile, the ultrapure water supply pipe 11 branches off when the hot ultrapure water supply pipe 21 is connected to it. This hot ultrapure water supply pipe 21 is equipped with a preheater 22 as a first heating means for heating the ultrapure water W1, a heater 23 as a second heating means, and an ultrafiltration membrane (UF membrane) 24. The ultrapure water W1, or hot ultrapure water W2, heated here is supplied to the second use point 25 at the end of the hot ultrapure water supply pipe 21. The unused hot ultrapure water W2 at the second use point 25 is then returned to the sub-tank 2 via the return pipe 26, through the preheater 22, and then through the return pipe 27 which is continuous with the return pipe 26.

[0027] Furthermore, downstream of the ultrafiltration membrane (UF membrane) 24 of the hot ultrapure water supply pipe 21 and upstream of the second use point 25, a water sampling line 31 is connected, branching off from the hot ultrapure water supply pipe 21. This water sampling line 31 is equipped with an on / off valve 32 and a heat exchanger 33 for cooling the hot ultrapure water W2. Downstream of this cooling heat exchanger 33, various elements 34 such as a water sampling means, an online concentration device, and an online monitor are provided.

[0028] In the above-described hot ultrapure water production system, in this embodiment, the hot ultrapure water supply piping 21 is made of a polymer material containing halogen elements such as fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) as repeating units. Specifically, examples include polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene (ETFE), ethylene-chlorotrifluoroethylene alternating copolymer (ECTFE), perfluoroalkoxyalkane (PFA), and polyvinyl chloride (PVC) as wetted members. In this embodiment, piping made of these polymer materials is used not only for the hot ultrapure water supply piping 21 but also for the ultrapure water supply piping 11 from the non-regenerative ion exchange resin device 9 of the secondary pure water device 1. In Figure 1, piping made of polymer material containing these halogen elements as repeating units is shown with a thick line.

[0029] Furthermore, the water sampling line 31 is made of a polymer material or metal material that does not contain halogen elements in its repeating units. Examples of polymer materials that do not contain halogen elements in their repeating units include polyethylene (PE), polyolefins such as polypropylene (PP), polyphenylene sulfide (PPS), polycarbonate (PC), polyimide (PI), and styrene-based elastomers. Among these, polyolefins such as polyethylene (PE) and polypropylene (PP) are preferred in terms of versatility, and low-eluting polyethylene is particularly preferred. Examples of metal materials include SUS material (SUS304, SUS316, etc.) and Ti material. This water sampling line 31 includes not only piping but also nipples, valves, fittings, gaskets, tubes, etc.

[0030] The heat exchanger 33 for cooling can be made of a metal material such as Ti or SUS, and a shell-and-tube type or plate type heat exchanger can be suitably used. Specifically, it is preferable to select and use one that can cool the temperature of the warm ultrapure water W1 collected in the water sampling line 31 to 40°C or lower, particularly to 20-25°C, depending on the temperature of the warm ultrapure water W1.

[0031] Element 34 is a device or component that is installed as appropriate depending on the purpose of water sampling, and includes water quality measuring instruments such as resistivity meters and TOC meters, introduction units for online monitors such as particulate meters, introduction units for online concentration devices, bottle sampling components for metals and ions, and in particular, water sampling equipment such as bottle sampling components for anions.

[0032] (Method for producing warm ultrapure water) Next, the method for producing warm ultrapure water using such a warm ultrapure water production system will be described below.

[0033] In the pretreatment system, raw water is pretreated by filtration, coagulation and sedimentation, and microfiltration membranes, primarily to remove suspended solids.

[0034] A primary pure water production system is equipped with a reverse osmosis (RO) membrane separator, a degasser, a regenerative ion exchange system (such as a mixed-bed or 4-bed 5-column type), an electrodeionizer, an ultraviolet (UV) irradiation oxidation system, and other oxidation devices to remove most of the electrolytes, particulate matter, and live bacteria from the pre-treated water. For example, a primary pure water production system consists of a heat exchanger, an RO membrane separator, a mixed-bed ion exchange system, and a degasser.

[0035] In this embodiment, the primary pure water W produced by this primary pure water production device is processed by the secondary pure water device 1 as follows. That is, when the primary pure water W at about 25°C is stored in the sub-tank 2, it is supplied from the water supply pipe 2A by the water supply pump 3, sequentially processed by the ultraviolet oxidation device 5, the hydrogen peroxide decomposition device 6, and the membrane degassing device 7, then the water supply pressure is increased by the booster pump 8 and processed by the non-regenerative ion exchange resin device 9, and finally the fine particles are removed by the ultrafiltration membrane 10 to produce ultrapure water W1 at about 20 to 30°C. The produced ultrapure water W1 is supplied from the ultrapure water supply pipe 11 to the first use point 12 that uses ultrapure water W1 at room temperature, and the unused ultrapure water W1 is refluxed from the return pipe 13 to the sub-tank 2 and reused.

[0036] On the other hand, a part of the produced ultrapure water W1 is also supplied from the ultrapure water supply pipe 11 to the warm ultrapure water supply pipe 21 made of a polymer material containing a halogen element as a repeating unit. This warm ultrapure water supply pipe 21 is heated by the waste heat exchanger 22 to 30 to 50°C, for example, about 42°C, and then heated by the heater 23 to 60 to 75°C, for example, about 70°C, and supplied as warm ultrapure water W2 to the second use point 25 through the UF membrane 24.

[0037] Then, the surplus warm ultrapure water W2 not used at the second use point 25 flows through the return pipe 26, is introduced into the waste heat exchanger 22 as a heat source fluid, exchanges heat with the ultrapure water W1 introduced into the warm ultrapure water supply pipe 21, cools down to about 40°C, and then is sent from the return pipe 27 to the sub-tank 2.

[0038] In the supply of the warm ultrapure water W2 as described above, the on-off valve 32 is opened to introduce the warm ultrapure water W2 into the sampling line 31 for water quality inspection of the warm ultrapure water W2. This warm ultrapure water W2 is cooled to a water temperature of 40°C or less, particularly 20 to 25°C, in the heat exchanger 33 for cooling. If the temperature of the cooled warm ultrapure water W2 exceeds 40°C, it is not preferable because it becomes difficult to reduce the generation of eluates from the nipples, valves, joints, gaskets, and sampling bottles that constitute the sampling line 31.

[0039] Then, the warm ultrapure water W2 cooled by the water sampling line 31 is used in the element 34 to measure water quality such as resistivity and TOC, measure fine particles or the like with an on-line monitor, introduce it into an on-line concentrator for trace analysis, or pour it into a bottle sampling member for metals, ions, etc., particularly an anion bottle sampling member.

[0040] At this time, in this embodiment, since the water sampling line 31 is made of a polymer material or a metal material that does not contain a halogen element in the repeating unit, the elution component of the halogen from the warm ultrapure water supply pipe 21 made of a polymer material containing a halogen element in the repeating unit is not added, so that accurate water quality evaluation of the warm ultrapure water production system can be carried out. Particularly when a metal material is used, there is no permeation of dissolved gas or the like, so it is possible to collect water without sucking in dissolved gas or volatile organic substances from the surrounding environment even when the surrounding environment is bad. In addition, olefin resins and metal materials are cheaper than polymer materials containing a halogen element in the repeating unit, so cost reduction for the water sampling line can be expected, and they are suitable as components of the water sampling line because they are easily available.

[0041] Further, as a secondary effect, when a polymer material that does not contain a halogen element in the repeating unit is used, it can be cited as an advantage that the environmental load is low when discarded. Particularly for members such as the water sampling line that are consumables for short-term water sampling purposes, it is not preferable that the polymer material contains halogen. In addition, for polymer materials containing a halogen element, particularly F, the raw material is fluorite (calcium fluoride (CaF ２ )), and elution of Ca derived from the raw material is characteristic. By constructing the water sampling line with a polymer material that does not contain a halogen element, elution addition from the water sampling line can be suppressed, and accurate water quality evaluation of the warm ultrapure water production system can be carried out. On the other hand, when a metal material is used, combined with the above effects, there is almost no absorption of dissolved gas or the like, so it is also possible to collect water without sucking in dissolved gas or volatile organic substances from the surrounding environment even when the surrounding environment is bad.

[0042] Although the present invention has been described above based on the embodiments described, the present invention is not limited to the embodiments described above and can be implemented in various modified forms. For example, the configuration of the primary pure water production apparatus and the secondary pure water production apparatus is not particularly limited, and as long as the temperature ultrapure water supply piping is made of a polymer material containing halogen elements in repeating units, and the water sampling line is made of a polymer material or metal material that does not contain halogen elements in repeating units, the present invention can be applied to primary pure water production apparatus and secondary pure water production apparatus with various configurations. Furthermore, the first use point 12 that uses ultrapure water W1 at room temperature is not required. Moreover, the element 34 is not limited to water sampling equipment such as an online monitor, an introduction section to an online concentration device, or bottle sampling members for metals or ions, but can be equipped with various devices and components.

[0043] The present invention will be described in more detail based on the following specific examples, but the present invention is not limited to the following examples.

[0044] [Comparative Example 1] Treatment volume: 15 m³ ３ A verification system for producing ultrapure water at 75°C was used, as shown in Figure 1, with a scale of 1 / hour. The ultrapure water W2 from the outlet of the UF membrane 24 was sampled from the sampling line 31 to verify its quality. The ultrapure water supply piping 21 was made of polyvinylidene fluoride (PVDF), and the sampling line 31 used stainless steel nipples, stainless steel ball valves, and stainless steel fittings as common components. The sampling tube material was a 5m tube made of a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene (PFA) (manufactured by Nitta Corporation, TA-4-6x4), and its effects were confirmed. This equipment has been in operation for more than two years, and there is almost no leaching from the equipment.

[0045] The 75°C ultrapure water W2 produced here was sampled in two forms: one without any additives and another with a NaF solution added to achieve a fluoride ion (F-) concentration of 15 ng / L. These were continuously passed through the sampling line 31 at a rate of 0.25 L / min. After cooling to room temperature (23-24°C) in a heat exchanger 33 on the secondary side of the sampling line 31, the water was introduced into the sampling booth, and bottle sampling was performed one week after the water was passed through. The F- of the sampled ultrapure water W2 was measured. ―The concentration was measured by ion chromatography. The results are shown in Table 1.

[0046] For the warm ultrapure water W2 at 75°C, samples with nothing added and those with CaCl added so that the Ca concentration is 5 ng / L were each used as the water sampling targets. Continuous water flow was carried out at 0.25 L / min in the water sampling line 31. After cooling to room temperature (23 - 24°C) with the heat exchanger 33 on the secondary side of the water sampling line 31, it was introduced into the sampling booth, and bottle water sampling was carried out after 1 week of water flow. The Ca concentration of the sampled warm ultrapure water W2 was measured by ion chromatography. The results are shown in Table 2. ２ For the warm ultrapure water W2 at 75°C, samples with dissolved oxygen removed and those with dissolved oxygen adjusted to 10 μg / L were each used as the water sampling targets. Continuous water flow was carried out at 0.25 L / min in the water sampling line 31. After cooling to room temperature (23 - 24°C) with the heat exchanger 33 on the secondary side of the water sampling line 31, it was introduced into the sampling booth, and bottle water sampling was carried out after 1 week of water flow. The dissolved oxygen concentration of the sampled cooled warm ultrapure water W2 was measured online using a dissolved oxygen meter. The results are shown in Table 3.

[0047] For the warm ultrapure water W2 at 75°C, samples with dissolved oxygen removed and those with dissolved oxygen adjusted to 10 μg / L were each used as the water sampling targets. Continuous water flow was carried out at 0.25 L / min in the water sampling line 31. After cooling to room temperature (23 - 24°C) with the heat exchanger 33 on the secondary side of the water sampling line 31, it was introduced into the sampling booth, and bottle water sampling was carried out after one week of water flow. The dissolved oxygen concentration of the sampled cooled warm ultrapure water W2 was measured online using a dissolved oxygen meter. The results are shown in Table 3.

[0048] 〔Example 1〕 In Comparative Example 1, as the water sampling tube material of the water sampling line 31, 5 m of a PE tube (manufactured by AS ONE Corporation, cross-linked two-layer polyethylene tube, heat-resistant temperature ~90°C) was used, and the F － concentration, Ca concentration, and dissolved oxygen concentration of the similarly cooled warm ultrapure water W2 were measured. The results are shown together in Tables 1 - 3.

[0049] 〔Example 2〕 In Comparative Example 1, as the water sampling tube material of the water sampling line 31, 5 m of a SUS304 tube (manufactured by KOMOORI Corporation, stainless steel round pipe) was used, and the F － concentration, Ca concentration, and dissolved oxygen concentration of the similarly cooled warm ultrapure water W2 were measured. The results are shown together in Tables 1 - 3.

[0050]

[0051] As is clear from Table 1, in the case of no addition, for the PFA tube of Comparative Example 1, the F at 20 ng / L －Elution of was confirmed, but in Examples 1 and 2, it was below the analytical limit (<5 ng / L). Also, F was added to warm ultrapure water W2. － When NaF solution was added to achieve a concentration of 15 ng / L, the PFA tube in Comparative Example 1 had a concentration of 35 ng / L of NaF. － The elution of F was confirmed, but in Examples 1 and 2, the added amount was 15 ng / L. From these findings, in the verification of the tube material, the standard sampled water W2 contains F － Although it contains almost no F, an additional 20 ng / L of elution is added from the PFA tube, while by selecting a material that does not contain halogen elements, the F in the hot ultrapure water production system － It was confirmed that accurate water quality assessment based on concentration can be performed.

[0052]

[0053] As is clear from Table 2, in the case without additives, a Ca elution of 0.4 ng / L was confirmed in the PFA tube of Comparative Example 1, while in Examples 1 and 2 it was 0.1 to 0.2 ng / L. Furthermore, CaCl was added to warm ultrapure water W2 to achieve a Ca concentration of 5 ng / L. ２ When Ca was added, 5.5 ng / L was detected in the PFA tube of Comparative Example 1, but it was lower in Examples 1 and 2, ranging from 5.1 to 5.3 ng / L. From these findings, it was confirmed that in the verification of tube materials, although the standard sample of warm ultrapure water contains almost no Ca, an additional 0.4 ng / L is leached from the PFA tube. On the other hand, by selecting a material that does not contain halogen elements, it is possible to accurately evaluate the water quality of Ca concentration in a warm ultrapure water production system.

[0054]

[0055] As is clear from Table 3, an increase in dissolved oxygen was observed in Comparative Example 1 and Example 1, but no increase in dissolved oxygen was observed in Example 2. Furthermore, when the dissolved oxygen concentration of warm ultrapure water W2 was adjusted to 10 μg / L, dissolved oxygen was detected at 15-20 μg / L in Comparative Example 1 and Example 1, but at 10 μg / L in Example 2. From these results, it was confirmed that using a metal material in the verification of the tube material eliminates the influence of the surrounding environment (such as the inhalation of dissolved gases) and allows for the simultaneous sampling of other parameters.

[0056] 1. Secondary pure water system (subsystem) 2. Subtank 2A. Water supply piping 3. Water supply pump 4. Heat exchanger 5. Ultraviolet oxidation device 6. Hydrogen peroxide decomposition device 7. Membrane degasser 8. Booster pump 9. Non-regenerative ion exchange resin device 10. Ultrafiltration membrane (UF membrane) 11. Ultrapure water supply piping 12. First use point 13. Return piping 21. Hot ultrapure water supply piping 22. Preheater (first heating means) 23. Heater (second heating means) 24. Ultrafiltration membrane (UF membrane) 25. Second use point 26. Return piping 27. Return piping 31. Water collection line 32. On / off valve 33. Heat exchanger for cooling 34. Element W: Primary pure water W1: Ultrapure water W2: Hot ultrapure water

Claims

1. A hot ultrapure water production system comprising: an ultrapure water production unit equipped with a primary pure water production device and a secondary pure water production device; a hot ultrapure water supply pipe for supplying ultrapure water from the ultrapure water production unit to a point of use; a heating means provided in the hot ultrapure water supply pipe; and a water sampling line branching from the hot ultrapure water supply pipe, wherein the hot ultrapure water supply pipe is made of a polymer material containing halogen elements in repeating units, and the water sampling line is made of a polymer material or metallic material that does not contain halogen elements in repeating units.

2. The hot ultrapure water production system according to claim 1, wherein the water sampling line is composed of two or more of the following: nipples, valves, fittings, pipes, or tubes.

3. The hot ultrapure water production system according to claim 2, wherein the water collection line has a heat exchanger for cooling.

4. The thermal ultrapure water production system according to claim 3, wherein the cooling heat exchanger is a metal shell-and-tube or plate heat exchanger.

5. The hot ultrapure water production system according to claim 4, wherein the heat exchanger for cooling is capable of cooling the water temperature of the hot ultrapure water collected in the water collection line to 40°C or below.

6. A thermal ultrapure water production system according to any one of claims 3 to 5, further comprising one or more bottle sampling mechanisms, online concentration devices, and introduction mechanisms to online monitors downstream of the heat exchanger for cooling the water sampling line.

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