CA1218870A - Apparatus for measuring impurities in ultrapure water - Google Patents
Apparatus for measuring impurities in ultrapure waterInfo
- Publication number
- CA1218870A CA1218870A CA000448449A CA448449A CA1218870A CA 1218870 A CA1218870 A CA 1218870A CA 000448449 A CA000448449 A CA 000448449A CA 448449 A CA448449 A CA 448449A CA 1218870 A CA1218870 A CA 1218870A
- Authority
- CA
- Canada
- Prior art keywords
- detector
- ultrapure water
- impurities
- hollow
- tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 229910021642 ultra pure water Inorganic materials 0.000 title claims abstract description 38
- 239000012498 ultrapure water Substances 0.000 title claims abstract description 38
- 239000012535 impurity Substances 0.000 title claims abstract description 33
- 230000035945 sensitivity Effects 0.000 claims abstract description 7
- 239000003792 electrolyte Substances 0.000 claims description 33
- 238000005259 measurement Methods 0.000 claims description 24
- 239000007788 liquid Substances 0.000 claims description 23
- 238000005868 electrolysis reaction Methods 0.000 claims description 7
- 239000007789 gas Substances 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 229920003002 synthetic resin Polymers 0.000 claims description 6
- 239000000057 synthetic resin Substances 0.000 claims description 6
- 239000011244 liquid electrolyte Substances 0.000 claims description 4
- PYVHTIWHNXTVPF-UHFFFAOYSA-N F.F.F.F.C=C Chemical compound F.F.F.F.C=C PYVHTIWHNXTVPF-UHFFFAOYSA-N 0.000 claims description 2
- 229920005989 resin Polymers 0.000 claims description 2
- 239000011347 resin Substances 0.000 claims description 2
- 229920002050 silicone resin Polymers 0.000 claims description 2
- 238000000034 method Methods 0.000 abstract description 16
- 238000001514 detection method Methods 0.000 abstract description 6
- 241000894006 Bacteria Species 0.000 abstract description 4
- 239000000428 dust Substances 0.000 abstract description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 239000011521 glass Substances 0.000 description 5
- 238000007796 conventional method Methods 0.000 description 4
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 238000005034 decoration Methods 0.000 description 3
- 238000005070 sampling Methods 0.000 description 3
- 238000000149 argon plasma sintering Methods 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 230000000994 depressogenic effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000790 scattering method Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000615 nonconductor Substances 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 210000002741 palatine tonsil Anatomy 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/12—Coulter-counters
-
- G01N15/131—
Abstract
ABSTRACT
A novel apparatus is provided for measuring the number of sizes of micro impurities such as fine dust or bacteria floating in ultrapure water. The apparatus is improved over the electrical pulse method for a high detection sensitivity and high precision and which does not operate erratically.
A novel apparatus is provided for measuring the number of sizes of micro impurities such as fine dust or bacteria floating in ultrapure water. The apparatus is improved over the electrical pulse method for a high detection sensitivity and high precision and which does not operate erratically.
Description
- ~218870 APPARATUS FOR MEASURING IMPURITIES
IN ULTRAPURE WATER
background of the Invention 1. Field of the Invention:
The present invention relates to an apparatus for measuring the number or sizes of micro impurities such as fine dust or bacteria floating in ultrapure water.
IN ULTRAPURE WATER
background of the Invention 1. Field of the Invention:
The present invention relates to an apparatus for measuring the number or sizes of micro impurities such as fine dust or bacteria floating in ultrapure water.
2. Description of the Prior Art:
Ultrapure water is water which has a specific resistivity of 16 MQ-cm (25C) and contains impurities such as fine particles, organic materials, inorganic materials or bacteria only in units of pub (1/1,000 of the Pam). Ultrapure water is indispensable to the manufacture of IT semiconductors. Especially, regarding micro impurities, since the pattern size of current Lois is as small as 1 em, ultrapure water must not contain micro impurities having a size of 0.1 em or more.
Methods of measuring micro impurities (to be referred to as impurities for brevity hereinafter) floating in ultrapure water currently include the light blocking method, the light scattering method, the laser scattering method, the filter method, and the electrical pulse method.
Of these methods, the light blocking method, the light scattering method, and the laser scattering method which utilize light provide only a low precision and cannot measure or detect impurities having a size issue of 0.5 lam or less or transparent impurities such as dead bacteria. Although the filter method which measures the impurities trapped by a microscope allows measurement of impurities having a size of 0.1 em or less, sampling and measurement procedures require much labor and time.
In the electrical pulse method, a change in resistance which is obtained when an impurity passes through a small hole in a detector is obtained as a voltage pulse. The electrical pulse method theoretically allows measurement of impurities having a size of 0.1 em or less and allows easy sampling and measurement. However, it sometimes happens that the electrolyte or ultrapure water causes electrolysis between the electrodes, bubbles become attached to the surfaces of the electrodes, and the detection sensitivity is significantly degraded.
When a high current is flowed to improve detection sense-tivity, electrolysis becomes more vigorous to present danger. Furthermore, since the interior of a detector is kept at a reduced pressure to draw by suction ultrapure water through the small hole in the detector, dissolved gases in the electrolyte in the detector or a manometer appear in the form of bubbles and adversely affect the operation of the manometer.
Summary of the Invention The present invention has been made in consideration of the drawbacks of the conventional methods and has for its object to provide an apparatus for measuring impurities in ultrapure water, which is improved over the electrical pulse method for a high detection sensitivity and high precision and which does not operate erratically.
In order to achieve this object, according to the present invention, there is provided in an electrical pulse apparatus for measuring impurities in ultrapure water which includes a container for the ultrapure water whose impurities are to be measured, a hollow detector which has a portion extending into said container so as to be surrounded by said ultrapure water, said portion of said hollow detector having a small hole therein to enable ultrapure water in said container to pass into said hollow detector, a supply tank for a liquid electrolyte, a first conduit system connected between said supply tank and said hot-low detector for delivering said liquid electrolyte from said supply tank to said hollow detector, a second conduit system connected to said hollow detector to remove liquid therein, a first electrode positioned in said hollow detector, a second electrode extending into said container outside said hollow detector so as to dip into the ultrapure water therein, and elect tribal means connected to said first and second electrodes to cause a current to flow there between through said ultrapure water in said container and the liquid in said hollow detector and to detect voltage pulses produced by impurities passing through said small hole in said hollow detector, the improvement wherein a decoration device is connected to said first conduit system to decorate the electrolyte passing through said first conduit system such that bubbles formed by electrolysis at said first and second electrodes will be redissolved, thus increasing the speed and sensitivity of measurement and reducing the current needed for ~Z1~8~0 measurement, said decoration device comprising a chamber, a vacuum pump connected to said chamber and a tube extending through said chamber, said tube being connected into said first conduit system, said tube being made of a synthetic resin which is previous to gases but not liquids.
An embodiment of the present invention will now be described with reference to the accompanying drawings.
Brief Description of the Drawings Figure 1 is a view showing an embodiment of a measuring apparatus of the present invention;
Figure 2 is a sectional view showing an embodiment of a decorating device to be used in the measuring apparatus of the present invention; and Figure 3 is a cross-sectional view of the decorating device shown in Figure 2.
Detailed Description of the Preferred Embodiment A detector 1 has a hollow shape and consists of an electrical insulator such as glass. A small hole 2 is formed in the lower portion of the side wall of the detector to communicate the interior and exterior of the detector 1. An internal elect trove (positive electrode) 3 is placed in the detector 1, while an external electrode (negative electrode) 4 is placed outside the detector 1. An electrolyte supply tube 5 and an exhaust tube 6 are connected to the detector 1.
-pa-~218870 The small hole 2 is formed in the lower portion of the side wall of the detector 1 such that a chip of a rugby or sapphire with the small hole 2 therein is fitted in the side wall of the detector 1. The small hole 2 has a small size (e.g., 10 em diameter) so as not to allow simultaneous passage of more than one impurity.
The internal electrode 3 and the external electrode 4 are arranged at inside and outside the detector 1. A
constant DC current is flowed between the electrodes 3 and 4, which are connected to a pulse detecting circuit 7.
The detecting circuit 7 is connected to a series circuit of an amplifying circuit 8 for amplifying a voltage pulse having a small amplitude, a discriminating circuit 9 for discriminating and shaping the amplified voltage pulse, a measuring circuit 10 for counting the voltage pulse, a correcting circuit 11 for correcting an error of the count of the voltage pulses, and a displaying circuit 12 for digitally displaying the number of the impurities thus measured.
The electrolyte supply tube 5 is for supplying electrolyte a from a water supply bottle 13 to the interior of the detector 1. A decorating device 14 is disposed at the part of the path of the tube 5 which is at the side of the water supply bottle 13. A
manometer 15 for measuring the liquid level by means of a photo sensor is disposed at the part of the path of the tube 5 which is at the side of the detector 1. A branch tube 5' is connected between the decorating device 14 and the manometer 15. The branch tube 5' is connected to the exhaust tube 6 of the detector 1 through a three-way 12~8870 electromagnetic valve 16. A glass tank 17 communicates with an exhaust bottle 18 and a vacuum pump lo is connected to the exhaust bottle 18. Reference numeral 20 denotes a pressure sensor for maintaining the interior of the exhaust bottle at a given negative pressure.
The decorating device I decorates dissolved gases in the electrolyte _ contained in the water supply bottle 13 and supplies the decorated electrolyte _ to the detector 1. As shown in Figs. 2 and 3, the decorating device 14 comprises a tube 21 for flowing the electrolyte a there-through, and a reduced pressure tank 22 housing the tube 21 therein and communicating with a vacuum pump 23.
The tube 21 consists of a synthetic resin material which passes gases only and does not pass liquids, such as an ethylene tetrafluoride resin material or silicone resin material. The inner diameter, wall thickness or length of the tube 21 vary in accordance with the material used and combinations of the adopted inner diameter, thickness and length. According to an experiment conducted, when the inner diameter of the tube 21 was 1.0 to 2.0 mm, the wall thickness was 0.2 to 0.5 mm, the length was 10 to 20 m, and the flow rate of the electrolyte which is to be decorated was 10 to 25 ml/min, decoration could be performed substantially completely. The tube 21 is housed in the reduced pressure tank 22 in a wound form without forming any bent or twist.
The reduced pressure tank 22 is formed into a sealed box shape using a synthetic resin material or a metallic material and is connected to the vacuum pump 23 to be evacuated thereby. One end of the tube 21 in the wound form is connected to an inlet port connector 2g, while the other end thereof is connected to an output port connector 25. The reduced pressure tank 22 is connected through the connectors 24 and 25 to the path for supplying the electrolyte a from the water supply bottle 13 to the detector 1, that is, an intermediate portion of the electrolyte supply tube 5. While the electrolyte a to be decorated is flowed through the tube 21, the dissolved gases are decorated from the electrolyte a and the decorated electrolyte is supplied to the interior of the detector 1.
The mode of operation of the apparatus according to the present invention will now be described.
The electrolyte a contained in the water supply bottle 13 is supplied to the liquid circuit. When a water supply switch (not shown) is depressed (ON), a valve (to be referred to as an A valve hereinafter) 26 for opening/closing between the decorating device 14 and the electrolyte supply tube 5 is opened, and NC and COY
sides of a three-way electromagnetic valve (to be referred to as a B valve hereinafter) 16 for opening/closing the branch tube 5' of the electrolyte supply tube 5, the exhaust tube 6 and the glass tank 17 are opened. By the suction force of the vacuum pump 19, the electrolyte a in the water supply bottle 13 is supplied to the decorating device 14 and is decorated through the tube 21. The decorated electrolyte is supplied to -the interior of the detector: through the A valve 26 and the manometer 15. The decorated electrolyte inside the detector 1 is flowed to the glass tank 17 through the exhaust tube 6 and the B valve 16 and is then exhausted into the exhaust 121~870 bottle 18. Then, the overall liquid circuit is filled with the decorated electrolyte a.
Subsequently, the A valve 26 is closed, and a reagent bottle 27 holding ultrapure water _ to be measured therein is placed below the detector 1. The small hole 2 of the detector 1 is immersed into the ultrapure water _ to be measured, and a current is flowed between the internal and external electrodes 3 and 4 through the electrolyte a and the ultrapure water _. Measurement is thus started.
The electrolyte is mixed with the ultrapure water b for providing a good conductivity.
When a measurement start switch (not shown) is depressed (ON), the A valve 26 is closed, and the NC
and the COY sides of the B valve 16 are opened. At the same time, the NO and COY sides of a three-way electromagnetic valve (to be referred to as a C valve hereinafter) 29 interposed between the A valve 26 and the B valve 16 are opened. Then, the electrolyte in the liquid circuit is drawn from the exhaust tube 6 of the detector 1 to the exhaust bottle 18 through the glass tank 17 by means of the suction force of the vacuum pump 13. At the same time, air is introduced into the liquid circuit from the NO side of the C valve 29, and the liquid level in the manometer 15 is lowered to level Pi through level Pi. When the liquid level of the manometer 15 reaches level Pi, a photo sensor aye is turned on. Upon turning on of the photo sensor aye, the NC side of the B
valve 16 is closed and the NO and COY sides thereof are opened. At the same time, the NO side of the C valve 29 is closed and the COY and NC sides thereof are opened, 12~8870 and the liquid level of the manometer 15 begins to rise by the suction force of the vacuum pump 19. Since the interior of the detector 1 is kept at a negative pressure, the ultrapure water b in the reagent bottle 27 is drawn into the detector 1 through the small hole 2. When the liquid level of the manometer 15 reaches level Pi, a photo sensor 15b is turned on. The detecting circuit 7 and so on are operated through a controlling circuit 28 to start measurement. When the ultrapure water _ in the reagent bottle 27 is drawn into the detector 1 through the small hole 2, impurities in the ultrapure water b are also drawn. When an impurity passes through the small hole 2 of the detector 1, a resistance between the internal and external electrodes 3 and 4 is instant tonsil increased, and an electrical pulse having an amplitude proportional to the size of the passed impurity is generated. The pulse is then detected by the detecting circuit 7 and is processed by the amplifying circuit 8, the discriminating circuit 9, the measuring circuit 10, and the correcting circuit 11. The number of impurities is digitally displayed at the displaying circuit 12.
When the liquid level in the manometer 15 reaches level Pi; a photo sensor 15c is turned on and the measurement is terminated. While the liquid level in the manometer 15 rises from level Pi to level Pi, the amount of the ultrapure water drawn into the detector 1 through the small hole 2 reaches the unit suction amount. Thus, the number of impurities contained in the unit suction amount of ultrapure water b is thus counted.
1218~370 Since the apparatus of the present invention has the construction as described above, it provides the following effects:
I The apparatus of the invention allows easy sampling and measurement as in the case of the convent tonal electrical pulse method. The apparatus allows quick measurement of the number and size of impurities contained in ultrapure water with east.
(2) When the size (diameter) of the small hole in the detector is properly selected, theoretically measurement of impurities having a size of 0.1 my or less can be performed. An actual apparatus allowed measurement of impurities having a size of 0.1 my.
Ultrapure water is water which has a specific resistivity of 16 MQ-cm (25C) and contains impurities such as fine particles, organic materials, inorganic materials or bacteria only in units of pub (1/1,000 of the Pam). Ultrapure water is indispensable to the manufacture of IT semiconductors. Especially, regarding micro impurities, since the pattern size of current Lois is as small as 1 em, ultrapure water must not contain micro impurities having a size of 0.1 em or more.
Methods of measuring micro impurities (to be referred to as impurities for brevity hereinafter) floating in ultrapure water currently include the light blocking method, the light scattering method, the laser scattering method, the filter method, and the electrical pulse method.
Of these methods, the light blocking method, the light scattering method, and the laser scattering method which utilize light provide only a low precision and cannot measure or detect impurities having a size issue of 0.5 lam or less or transparent impurities such as dead bacteria. Although the filter method which measures the impurities trapped by a microscope allows measurement of impurities having a size of 0.1 em or less, sampling and measurement procedures require much labor and time.
In the electrical pulse method, a change in resistance which is obtained when an impurity passes through a small hole in a detector is obtained as a voltage pulse. The electrical pulse method theoretically allows measurement of impurities having a size of 0.1 em or less and allows easy sampling and measurement. However, it sometimes happens that the electrolyte or ultrapure water causes electrolysis between the electrodes, bubbles become attached to the surfaces of the electrodes, and the detection sensitivity is significantly degraded.
When a high current is flowed to improve detection sense-tivity, electrolysis becomes more vigorous to present danger. Furthermore, since the interior of a detector is kept at a reduced pressure to draw by suction ultrapure water through the small hole in the detector, dissolved gases in the electrolyte in the detector or a manometer appear in the form of bubbles and adversely affect the operation of the manometer.
Summary of the Invention The present invention has been made in consideration of the drawbacks of the conventional methods and has for its object to provide an apparatus for measuring impurities in ultrapure water, which is improved over the electrical pulse method for a high detection sensitivity and high precision and which does not operate erratically.
In order to achieve this object, according to the present invention, there is provided in an electrical pulse apparatus for measuring impurities in ultrapure water which includes a container for the ultrapure water whose impurities are to be measured, a hollow detector which has a portion extending into said container so as to be surrounded by said ultrapure water, said portion of said hollow detector having a small hole therein to enable ultrapure water in said container to pass into said hollow detector, a supply tank for a liquid electrolyte, a first conduit system connected between said supply tank and said hot-low detector for delivering said liquid electrolyte from said supply tank to said hollow detector, a second conduit system connected to said hollow detector to remove liquid therein, a first electrode positioned in said hollow detector, a second electrode extending into said container outside said hollow detector so as to dip into the ultrapure water therein, and elect tribal means connected to said first and second electrodes to cause a current to flow there between through said ultrapure water in said container and the liquid in said hollow detector and to detect voltage pulses produced by impurities passing through said small hole in said hollow detector, the improvement wherein a decoration device is connected to said first conduit system to decorate the electrolyte passing through said first conduit system such that bubbles formed by electrolysis at said first and second electrodes will be redissolved, thus increasing the speed and sensitivity of measurement and reducing the current needed for ~Z1~8~0 measurement, said decoration device comprising a chamber, a vacuum pump connected to said chamber and a tube extending through said chamber, said tube being connected into said first conduit system, said tube being made of a synthetic resin which is previous to gases but not liquids.
An embodiment of the present invention will now be described with reference to the accompanying drawings.
Brief Description of the Drawings Figure 1 is a view showing an embodiment of a measuring apparatus of the present invention;
Figure 2 is a sectional view showing an embodiment of a decorating device to be used in the measuring apparatus of the present invention; and Figure 3 is a cross-sectional view of the decorating device shown in Figure 2.
Detailed Description of the Preferred Embodiment A detector 1 has a hollow shape and consists of an electrical insulator such as glass. A small hole 2 is formed in the lower portion of the side wall of the detector to communicate the interior and exterior of the detector 1. An internal elect trove (positive electrode) 3 is placed in the detector 1, while an external electrode (negative electrode) 4 is placed outside the detector 1. An electrolyte supply tube 5 and an exhaust tube 6 are connected to the detector 1.
-pa-~218870 The small hole 2 is formed in the lower portion of the side wall of the detector 1 such that a chip of a rugby or sapphire with the small hole 2 therein is fitted in the side wall of the detector 1. The small hole 2 has a small size (e.g., 10 em diameter) so as not to allow simultaneous passage of more than one impurity.
The internal electrode 3 and the external electrode 4 are arranged at inside and outside the detector 1. A
constant DC current is flowed between the electrodes 3 and 4, which are connected to a pulse detecting circuit 7.
The detecting circuit 7 is connected to a series circuit of an amplifying circuit 8 for amplifying a voltage pulse having a small amplitude, a discriminating circuit 9 for discriminating and shaping the amplified voltage pulse, a measuring circuit 10 for counting the voltage pulse, a correcting circuit 11 for correcting an error of the count of the voltage pulses, and a displaying circuit 12 for digitally displaying the number of the impurities thus measured.
The electrolyte supply tube 5 is for supplying electrolyte a from a water supply bottle 13 to the interior of the detector 1. A decorating device 14 is disposed at the part of the path of the tube 5 which is at the side of the water supply bottle 13. A
manometer 15 for measuring the liquid level by means of a photo sensor is disposed at the part of the path of the tube 5 which is at the side of the detector 1. A branch tube 5' is connected between the decorating device 14 and the manometer 15. The branch tube 5' is connected to the exhaust tube 6 of the detector 1 through a three-way 12~8870 electromagnetic valve 16. A glass tank 17 communicates with an exhaust bottle 18 and a vacuum pump lo is connected to the exhaust bottle 18. Reference numeral 20 denotes a pressure sensor for maintaining the interior of the exhaust bottle at a given negative pressure.
The decorating device I decorates dissolved gases in the electrolyte _ contained in the water supply bottle 13 and supplies the decorated electrolyte _ to the detector 1. As shown in Figs. 2 and 3, the decorating device 14 comprises a tube 21 for flowing the electrolyte a there-through, and a reduced pressure tank 22 housing the tube 21 therein and communicating with a vacuum pump 23.
The tube 21 consists of a synthetic resin material which passes gases only and does not pass liquids, such as an ethylene tetrafluoride resin material or silicone resin material. The inner diameter, wall thickness or length of the tube 21 vary in accordance with the material used and combinations of the adopted inner diameter, thickness and length. According to an experiment conducted, when the inner diameter of the tube 21 was 1.0 to 2.0 mm, the wall thickness was 0.2 to 0.5 mm, the length was 10 to 20 m, and the flow rate of the electrolyte which is to be decorated was 10 to 25 ml/min, decoration could be performed substantially completely. The tube 21 is housed in the reduced pressure tank 22 in a wound form without forming any bent or twist.
The reduced pressure tank 22 is formed into a sealed box shape using a synthetic resin material or a metallic material and is connected to the vacuum pump 23 to be evacuated thereby. One end of the tube 21 in the wound form is connected to an inlet port connector 2g, while the other end thereof is connected to an output port connector 25. The reduced pressure tank 22 is connected through the connectors 24 and 25 to the path for supplying the electrolyte a from the water supply bottle 13 to the detector 1, that is, an intermediate portion of the electrolyte supply tube 5. While the electrolyte a to be decorated is flowed through the tube 21, the dissolved gases are decorated from the electrolyte a and the decorated electrolyte is supplied to the interior of the detector 1.
The mode of operation of the apparatus according to the present invention will now be described.
The electrolyte a contained in the water supply bottle 13 is supplied to the liquid circuit. When a water supply switch (not shown) is depressed (ON), a valve (to be referred to as an A valve hereinafter) 26 for opening/closing between the decorating device 14 and the electrolyte supply tube 5 is opened, and NC and COY
sides of a three-way electromagnetic valve (to be referred to as a B valve hereinafter) 16 for opening/closing the branch tube 5' of the electrolyte supply tube 5, the exhaust tube 6 and the glass tank 17 are opened. By the suction force of the vacuum pump 19, the electrolyte a in the water supply bottle 13 is supplied to the decorating device 14 and is decorated through the tube 21. The decorated electrolyte is supplied to -the interior of the detector: through the A valve 26 and the manometer 15. The decorated electrolyte inside the detector 1 is flowed to the glass tank 17 through the exhaust tube 6 and the B valve 16 and is then exhausted into the exhaust 121~870 bottle 18. Then, the overall liquid circuit is filled with the decorated electrolyte a.
Subsequently, the A valve 26 is closed, and a reagent bottle 27 holding ultrapure water _ to be measured therein is placed below the detector 1. The small hole 2 of the detector 1 is immersed into the ultrapure water _ to be measured, and a current is flowed between the internal and external electrodes 3 and 4 through the electrolyte a and the ultrapure water _. Measurement is thus started.
The electrolyte is mixed with the ultrapure water b for providing a good conductivity.
When a measurement start switch (not shown) is depressed (ON), the A valve 26 is closed, and the NC
and the COY sides of the B valve 16 are opened. At the same time, the NO and COY sides of a three-way electromagnetic valve (to be referred to as a C valve hereinafter) 29 interposed between the A valve 26 and the B valve 16 are opened. Then, the electrolyte in the liquid circuit is drawn from the exhaust tube 6 of the detector 1 to the exhaust bottle 18 through the glass tank 17 by means of the suction force of the vacuum pump 13. At the same time, air is introduced into the liquid circuit from the NO side of the C valve 29, and the liquid level in the manometer 15 is lowered to level Pi through level Pi. When the liquid level of the manometer 15 reaches level Pi, a photo sensor aye is turned on. Upon turning on of the photo sensor aye, the NC side of the B
valve 16 is closed and the NO and COY sides thereof are opened. At the same time, the NO side of the C valve 29 is closed and the COY and NC sides thereof are opened, 12~8870 and the liquid level of the manometer 15 begins to rise by the suction force of the vacuum pump 19. Since the interior of the detector 1 is kept at a negative pressure, the ultrapure water b in the reagent bottle 27 is drawn into the detector 1 through the small hole 2. When the liquid level of the manometer 15 reaches level Pi, a photo sensor 15b is turned on. The detecting circuit 7 and so on are operated through a controlling circuit 28 to start measurement. When the ultrapure water _ in the reagent bottle 27 is drawn into the detector 1 through the small hole 2, impurities in the ultrapure water b are also drawn. When an impurity passes through the small hole 2 of the detector 1, a resistance between the internal and external electrodes 3 and 4 is instant tonsil increased, and an electrical pulse having an amplitude proportional to the size of the passed impurity is generated. The pulse is then detected by the detecting circuit 7 and is processed by the amplifying circuit 8, the discriminating circuit 9, the measuring circuit 10, and the correcting circuit 11. The number of impurities is digitally displayed at the displaying circuit 12.
When the liquid level in the manometer 15 reaches level Pi; a photo sensor 15c is turned on and the measurement is terminated. While the liquid level in the manometer 15 rises from level Pi to level Pi, the amount of the ultrapure water drawn into the detector 1 through the small hole 2 reaches the unit suction amount. Thus, the number of impurities contained in the unit suction amount of ultrapure water b is thus counted.
1218~370 Since the apparatus of the present invention has the construction as described above, it provides the following effects:
I The apparatus of the invention allows easy sampling and measurement as in the case of the convent tonal electrical pulse method. The apparatus allows quick measurement of the number and size of impurities contained in ultrapure water with east.
(2) When the size (diameter) of the small hole in the detector is properly selected, theoretically measurement of impurities having a size of 0.1 my or less can be performed. An actual apparatus allowed measurement of impurities having a size of 0.1 my.
(3) Although slight electrolysis is caused between the internal and external electrodes during measurement, the electrolyte in -the detector is sufficiently decorated so that bubbles formed upon electrolysis are easily dissolved in the electrolyte and may not become attached on the surfaces of the electrodes. Since bubbles are not attached to the surfaces of the electrodes, a current easily flows and only a small current need be flowed during the measuring operation. For this reason, electrolysis between the internal and external electrodes is hard to occur, and attachment of bubbles on the electrodes is prevented.
Since a constant current flows between the internal and external electrodes, measurement reproducibility is good and high detection sensitivity is obtained.
Since a constant current flows between the internal and external electrodes, measurement reproducibility is good and high detection sensitivity is obtained.
(4) In the conventional methods, when the measurement time it prolonged, bubbles are attached on the surfaces of the electrodes and the detection sensitivity is degraded as time elapses. Accordingly, the unit suction amount of ultrapure water is small (0.1 ml) and measurement error is large. However, in the apparatus of the present invention, the unit suction amount of ultrapure water can be increased (0.25 to 0.5 ml) and measurements free from errors can be obtained.
(5) In the conventional methods, after each measure-mint, bubbles formed on the surfaces of the electrodes must be washed away, resulting in much labor and loss of electrolyte. The apparatus of the invention does not require such a procedure.
(6) In the conventional methods, when a liquid circuit is kept at a negative pressure by a vacuum pump for drawing ultrapure water through a small hole of a detector, dissolved gases in the electrolyte form bubbles which are introduced in the manometer during measurement, thus causing erratic operation. However, in the apparatus of the invention the electrolyte in the liquid circuit is decorated substantially completely. Accordingly, even if the liquid circuit is reduced in pressure to a pressure of 560 Torn by a vacuum pump, bubbles are not formed.
Thus, the manometer may not operate erratically, and the liquid circuit can be kept at a high negative pressure to draw ultrapure water into the detector through the small hole within a short period of time. Measurement time can thus be reduced to the minimum.
.
~L~18870
Thus, the manometer may not operate erratically, and the liquid circuit can be kept at a high negative pressure to draw ultrapure water into the detector through the small hole within a short period of time. Measurement time can thus be reduced to the minimum.
.
~L~18870
(7) Since the measurement time is shortened, the portion of the electrolyte which is subjected to electoral-skis is reduced. The effects of items (3) and (4) are further enhanced.
(8) The decorated electrolyte from the decorating device can be supplied to the detector and the liquid circuit on the on-line basis. Operability of the apparatus is thus improved.
(9) The decorating device is compact in size and can be easily assembled in the measuring apparatus.
Thus, the object of the present invention can be achieved.
It is further understood by those skilled in the art that the foregoing description is that of preferred embodiments of the disclosed apparatus for measuring impurities in ultrapure water and that various changes and modifications may be made in the invention without departing from the spirit and scope thereof.
Thus, the object of the present invention can be achieved.
It is further understood by those skilled in the art that the foregoing description is that of preferred embodiments of the disclosed apparatus for measuring impurities in ultrapure water and that various changes and modifications may be made in the invention without departing from the spirit and scope thereof.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In an electrical pulse apparatus for measuring impurities in ultrapure water which includes a container for the ultrapure water whose impurities are to be measured, a hollow detector which has a portion extending into said container so as to be surrounded by said ultrapure water, said portion of said hollow detector having a small hole therein to enable ultrapure water in said container to pass into said hollow detector, a supply tank for a liquid electrolyte, a first conduit system connected between said supply tank and said hollow detector for delivering said liquid electrolyte from said supply tank to said hollow detector, a second conduit system connected to said hollow detector to remove liquid therein, a first electrode positioned in said hollow detector, a second electrode extending into said container outside said hollow detector so as to dip into the ultrapure water therein, and electrical means connected to said first and second electrodes to cause a current to flow there-between through said ultrapure water in said container and the liquid in said hollow detector and to detect voltage pulses pro-duced by impurities passing through said small hole in said hol-low detector, the improvement wherein a deaeration device is connected to said first conduit system to deaerate the electro-lyte passing through said first conduit system such that bubbles formed by electrolysis at said first and second electrodes will be redissolved, thus increasing the speed and sensitivity of measurement and reducing the current needed for measurement, said deaeration device comprising a chamber, a vacuum pump con-nected to said chamber and a tube extending through said chamber, said tube being connected into said first conduit system, said tube being made of a synthetic resin which is previous to gases but not liquids.
2. The electrical pulse apparatus as defined in claim 1, wherein said synthetic resin is an ethylene tetrafluoride resin material.
3. The electrical pulse apparatus as defined in claim 1, wherein said synthetic resin is a silicone resin material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58-117841 | 1983-06-28 | ||
| JP58117841A JPS608734A (en) | 1983-06-28 | 1983-06-28 | Measuring apparatus of impurity in ultrapure water |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1218870A true CA1218870A (en) | 1987-03-10 |
Family
ID=14721586
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000448449A Expired CA1218870A (en) | 1983-06-28 | 1984-02-28 | Apparatus for measuring impurities in ultrapure water |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4651087A (en) |
| JP (1) | JPS608734A (en) |
| CA (1) | CA1218870A (en) |
| DE (1) | DE3407442A1 (en) |
| FR (1) | FR2549229B1 (en) |
| GB (1) | GB2142434B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6271831A (en) * | 1985-09-25 | 1987-04-02 | Hitachi Ltd | Method and instrument for measuring impurity in liquid |
| JPH0814529B2 (en) * | 1986-02-17 | 1996-02-14 | 株式会社日立製作所 | Liquid foreign matter measurement system |
| JPH0663961B2 (en) * | 1986-03-24 | 1994-08-22 | 日本科学工業株式会社 | Method for measuring impurities in liquid and its measuring device |
| US4833622A (en) * | 1986-11-03 | 1989-05-23 | Combustion Engineering, Inc. | Intelligent chemistry management system |
| US4972137A (en) * | 1989-05-31 | 1990-11-20 | Coulter Electronics, Inc. | Isolation circuit for blood cell counter |
| US5183486A (en) * | 1990-12-04 | 1993-02-02 | Spectra-Physics, Inc. | Apparatus for degassing a liquid |
| US5945831A (en) * | 1997-06-10 | 1999-08-31 | Sargent; John S. | Volume charge density measuring system |
| JP4629901B2 (en) * | 2001-04-26 | 2011-02-09 | 株式会社四国総合研究所 | Defoaming pretreatment device for fine powder metering device in oil |
| US20160192880A9 (en) * | 2004-05-28 | 2016-07-07 | David Scott Utley | Intra-Oral Detector and System for Modification of Undesired Behaviors and Methods Thereof |
| JP5231028B2 (en) * | 2008-01-21 | 2013-07-10 | 東京エレクトロン株式会社 | Coating liquid supply device |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3921006A (en) * | 1974-09-16 | 1975-11-18 | Coulter Electronics | Particle counting apparatus including isolated manometer |
| GB2014870B (en) * | 1978-02-24 | 1982-09-02 | Du Pont | Degasser |
| JPS551816A (en) * | 1978-06-15 | 1980-01-09 | Mitsubishi Rayon Co Ltd | Vapor-liquid contactor |
| US4361803A (en) * | 1980-08-26 | 1982-11-30 | Coulter Electronics, Inc. | Apparatus for recirculating sweep flow electrolyte without a pump |
| US4434647A (en) * | 1981-07-27 | 1984-03-06 | Lockheed Corporation | Dynamic spot calibration for automatic particle counters |
-
1983
- 1983-06-28 JP JP58117841A patent/JPS608734A/en active Granted
-
1984
- 1984-02-24 US US06/583,355 patent/US4651087A/en not_active Expired - Fee Related
- 1984-02-27 FR FR8402942A patent/FR2549229B1/en not_active Expired
- 1984-02-27 GB GB08405041A patent/GB2142434B/en not_active Expired
- 1984-02-28 CA CA000448449A patent/CA1218870A/en not_active Expired
- 1984-02-29 DE DE19843407442 patent/DE3407442A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| DE3407442A1 (en) | 1985-01-03 |
| GB2142434B (en) | 1987-07-15 |
| FR2549229B1 (en) | 1989-06-02 |
| JPH0237979B2 (en) | 1990-08-28 |
| US4651087A (en) | 1987-03-17 |
| GB2142434A (en) | 1985-01-16 |
| GB8405041D0 (en) | 1984-04-04 |
| JPS608734A (en) | 1985-01-17 |
| FR2549229A1 (en) | 1985-01-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |