Ultra-pure water supply piping system

Details Ultra-pure water supply piping system Ultra-pure water supply piping system

1990-08-22

1992-04-21

Sever, Frank

Liquid purification or separation

Adjuncts

210542, B01D 6120

Patent

active

051065037

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

1. Technical Field
The present invention relates to a supply piping system for ultra-pure water to be used in large quantity in electronics industry for semiconductor products, biotechnology and pharmaceutical and medical industry.
2. Technical Background
The system according to this invention is applied widely in various industrial fields. Here, description will be given on the ultra-pure water piping system for electronics industry including the manufacture of semiconductor integrated circuits.
In recent years, ultra-pure water for electronics industry is produced by ultra-pure water producing system as shown in FIG. 3, and water is mostly supplied to the equipment to use ultra-pure water (may be called "use point" hereinafter, referring to the place to use ultra-pure water) through a piping system. In FIG. 3, an ultra-pure water supply piping system having 3 use points is shown as an example. In normal system, the number of the use points is far more than this. In FIG. 3, the primary pure water producing system is not shown.
In the following, description is given on the ultra-pure water manufacture and ultra-pure water supply to the use points in connection with FIG. 3. Key points to maintain water quality of ultra-pure water are the removal of dust and solid particles, removal of bacteria, and complete removal of various ions, silica, organic substances, etc. dissolved in water. In FIG. 3, primary pure water is supplied to a circulating water tank 102 through a primary pure water supply pipe 101. The primary pure water stored in the circulating water tank is pressurized by the pressure pump 103 and is purified by passing through an ultraviolet sterilizing unit (UV sterilizing unit) 104, a cartridge polishers 105, 106 and 107 and ultrafiltration units 108 and 109. 122 is a drain pipe of the ultrafiltration unit. The ultra-pure water thus purified is supplied to the use points 119, 120 and 121 through outward pipe 110, connection pipes 113, 114 and 115, and branching valves 116, 117 and 118 respectively. The ultra-pure water passing through the connection pipes 113, 114 and 115 are returned to the circulating water tank 102 through the inward pipe 112, and the circulation is repeated.
FIG. 4 is an emphasized view of an ultra-pure water supply piping system of FIG. 3. 201 comprehensively shows the ultra-pure water producing system. 131, 132 and 133 are the branching points of the connection pipes 113, 114 and 115 to the use points. The branching valves 116, 117 and 118 are integrated with the branching points 131, 132 and 133 respectively.
For the piping material, macromolecular materials such as clean vinyl chloride, PVDF, PEEK, etc. having circular and smooth surface and containing few contaminants in ultra-pure water are used. As the piping material with lowest dissolving ratio of contaminants, stainless steel pipe is used, which is produced by electropolishing the inner surface, by cleaning and drying thereafter and having passive film through oxidation in ultra-high purity oxygen at 500.degree.-600.degree. C. for 5-10 hours--particularly the passive film mainly consisting of Cr.sub.2 O.sub.3. Above all, the surface oxidized at 550.degree. C. for more than 9 hours has excellent property.
The supply piping system to the use points are provided with an outward pipe and an inward pipe as shown in FIGS. 3 and 4, and the connection pipes to the use points are furnished between them. The reasons are as follows: In FIGS. 3 and 4, only 3 use points are shown, whereas the number of the use points are normally far more than that. Therefore, the quantity of ultra-pure water flowing in the outward pipe is gradually decreased, and the quantity of water in the inward pipe is gradually increased. However, regardless of the using condition of each use point, the predetermined quantity of ultra-pure water is supplied to the use points from each connection pipe. Namely, the same quantity of water flows in the connection pipe upstream of the outward pipe and in the connection pipe downstream

REFERENCES:
patent: 4216185 (1980-08-01), Hopkins
patent: 4595498 (1986-06-01), Cohen et al.
Japanese Publication-Science Forum.
Ultra Pur Water Supply System, Chemical Engineering (1987) vol. 32, No. 2.

Affiliated with

Also associated with

Rating

Ultra-pure water supply piping system does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Ultra-pure water supply piping system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ultra-pure water supply piping system will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1583996