JP2000180367A - Tape-type gas measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tape-type gas measuring device which prevents a gas from creeping during a measurement and by which the gas can be detected with high reliability, by a structure wherein the side face of a contact part in which the gas comes into contact with the measuring region of a gas detecting tape comes into contact with the edge part on the side of the unused region of the detecting tape. SOLUTION: This tape-type gas measuring apparatus which is applied to a silane-gas monitoring operation or the like uses a cassette which houses a detecting tape 9. In the cassette, a window by which the detecting tape 9 is brought into contact with a measuring head 20 comprising a contact part 21 in which an opening 24 is formed/ Slopes which are expanded and opened to the outside are formed in the edge part 10a and the edge part 0b of the window, Then, in a measurement, the measuring head 20 makes its way from the window so as to elastically press the detecting tape 9 between itself and a receiver part 3c so that air or the like which contains a gas to be detected is made to flow to the surface of the detecting tape 9. Then, the edge parts 10a, 10b of the window are sealed by the slope 21a and the slope 21b of the contact part 21. As a result, it is possible to prevent the discoloration of the detecting tape 9 in its unused region due to a reactive gas which is contained in the air or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the concentration of a gas to be processed discharged from a gas processing apparatus.

[0002]

2. Description of the Related Art Among gases used in production sites, gases whose emission to the atmosphere is prohibited, for example, silane gas, etc.
Detoxified via the decomposition unit and released to the atmosphere. Since such a decomposition unit has a limit on the total amount of gas that can be decomposed, usually, the concentration of the gas to be decomposed discharged from the decomposition unit is monitored by a detector, and the concentration is increased to a predetermined concentration equal to or lower than a discharge allowable reference level. At this stage, the processing magazine of the disassembling unit is replaced.

Since such an extremely low concentration gas has a large detection error in an electrochemical gas sensor or a semiconductor gas sensor, a tape type gas in which a chemical which reacts with the test gas and develops a color is carried on a tape or the like. A concentration measuring device is frequently used.

[0004]

In such a tape type gas concentration measuring device, the reaction amount increases in proportion to the time of exposure to the test gas, and therefore cannot be detected by other detectors due to the integration effect. Although extremely low concentration gas can be detected with high reliability, there is a disadvantage that a detection error occurs in response to gas contained in the environment.

[0005] In order to alleviate such a problem, for example, as described in Japanese Patent Application Laid-Open No. 8-94529, a detection tape is housed in a cassette in which a window for partially inserting a measuring head is formed. Although discoloration due to contact with the glass has been prevented, there is still a problem that discoloration occurs in an unused area due to gas entering through a window. The present invention has been made in view of such a problem, and an object of the present invention is to prevent a gas from entering through a window of a cassette during measurement and to detect a test gas with high reliability. It is to provide a gas detection device which can be used.

[0006]

According to the present invention, there is provided a cassette for accommodating a gas detecting tape which changes an optical density by reacting with a measurement gas and having a window in a measurement area. A tape-type gas measuring device, comprising: a contact portion provided with an opening through which a gas is brought into contact with a measurement region of a gas detection tape; and a measurement head containing means for detecting the optical density in opposition to the opening. , The side surface of the contact portion is configured to contact at least the edge of the gas detection tape on the unused area side, which forms the window.

[0007]

During the measurement period, the unused area side of the window is sealed by the measurement head to prevent the gas detection tape from contacting the reactive gas.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of a gas detection tape type gas detection device according to the present invention. An operation panel 3 is provided on one side surface of a frame 2 which can be inserted into and removed from a frame 1 provided on a rack or the like of a gas decomposition unit. A cassette holder 4 for accommodating a later-described cassette is provided so as to be able to advance and retreat, and a sampling pump and a substrate on which a later-described signal processing circuit is provided are accommodated therein. Further, an inlet 2a for a purge gas such as nitrogen supplied to the gas decomposition unit is provided as necessary.

FIG. 2 shows an embodiment of the above-mentioned cassette, in which a housing reel 7 and a take-up reel 8 are wound on one side 6 of a long side of a case 5 constituting the cassette. A first window 10 for contacting the gas detection tape 9 with a detection head to be described later and a second window 11 for contacting a paper feed roller 26 are formed.

The first window 10 is formed substantially at the center of the side surface of the case 5, and its edges 10a and 10b are formed with sloping surfaces expanding outward. Tape guides are provided on both sides of the window 10. A part 12 is formed. In the vicinity of the window 10, a narrow portion is formed by protrusions 10c and 12a which protrude toward the tape side and are longer than the width of the tape 9.

On the other hand, the second window 11 is formed on the take-up reel 8 side of the case 5, and the pressing roller 13 which contacts the paper feed amount detecting roller 26 is arranged here. Note that reference numerals 14 and 15 in the drawings indicate guide rollers.

FIG. 3 is a block diagram showing one embodiment of the present invention. A driving mechanism (not shown) in which a measuring head 20 is provided outside the conveying path of the gas detecting tape 9 exposed from the window 10 of the cassette 16 is shown. Are disposed so as to be able to contact and separate from the gas detection tape 9.

As shown in FIG. 4, when the measuring head 20 is pushed into the first window 10 of the cassette, as shown in FIG.
A contact portion 21 having slopes 20a and 21b corresponding to the side edge 10a is formed, and an opening 24 communicating with the inlet 22 and the outlet 23 of the gas to be detected is provided here.

At the other end of the opening 24, an optical density sensor 25 comprising a light emitting means and a light receiving means is accommodated so that a reaction mark formed on the detection tape 9 can be detected.

The take-up motor 27 is connected to the take-up reel 8 in a state where the cassette is mounted.
To take up the amount necessary for one measurement.

Reference numeral 28 in the figure denotes a control unit, which is a measuring means 29 for calculating a gas concentration based on a signal from the optical density sensor 25 before starting sampling and after sampling for a predetermined time.
Paper feed control means 3 for retracting the measurement head 20 in accordance with the cycle of the measurement operation and feeding the detection tape 9 by a predetermined amount.
0, the measuring head 20 enters the window 10 after the paper is fed,
And a sampling control means 31 for operating a sampling pump (not shown).

In this embodiment, a cassette 1 accommodating a detection tape 9 which changes an optical density by reacting with a test gas.
When the holder 6 is loaded in the holder 4 and then the holder 4 is pushed into the frame 2, the contact portion 21 of the measuring head 20 faces the window 10 of the cassette 16 and the paper feed amount is detected in the second window 11. The rollers 26 face each other.

When it is detected that the cassette 16 has been loaded, the measuring head 20 and the paper feed amount detecting roller 26 enter the windows 11 and 12, respectively, and the measuring head 20 Crack down between. In this state, as shown in FIG. 4B, the edge 10a of the window 10 on the side where the unused area of the detection tape 9 is accommodated is sealed by the slope 20a of the measuring head 20, and the window 10 is moved to the unused area. Of the detection tape 9 due to other reaction gas contained in the atmosphere or the like is prevented.

In this state, the measuring means 29 detects and stores the signal from the optical density sensor 25, and the sampling control means 31 operates the sampling pump to start sampling. The air containing the test gas flows into the opening 24 from the inlet 21 by the operation of the sampling pump, flows on the surface of the detection tape 9, and is discharged from the outlet 22.

The coloring agent carried on the gas detection tape reacts in proportion to the concentration of the test gas, and reaction marks are formed on the gas detection tape. When the sampling for a predetermined time is completed in this way, the sampling control means 31
Stops the sampling pump, and the measuring means 29 detects the gas concentration from the optical density sensor 25 and detects the concentration of the test gas from the stored difference from the signal before the start of sampling.

At the stage when the detection of the gas concentration is completed, the paper feed control means 30 retracts the measuring head 20 as shown in FIG. The unused area is pulled out to the window 10 to prepare for the next measurement.

In the above-described embodiment, the gas to be detected passes through one surface of the gas detection tape. However, the gas detection tape based on a carrier having gas permeability has the following disadvantages. A similar effect is obtained even if a gas inlet is formed on one side of the tape and a suction port is formed on the other side of the tape so that the test gas can pass therethrough as seen in JP-A-8-94529. .

[0023]

As described above, in the present invention,
A cassette containing a gas detection tape that changes the optical density by reacting with the measurement gas and having a window in the measurement area, and a contact part with an opening for making gas contact with the measurement area of the gas detection tape. A tape-type gas measuring device comprising a measuring head containing means for detecting an optical density facing an opening, wherein at least an edge of an unused area side of the gas detecting tape forms a window, Is contacted, so that the unused area of the gas detection tape of the cassette window can be sealed even during the measurement period, and discoloration of the gas detection tape due to the reactive gas can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a measuring device of the present invention.

FIGS. 2 (a) and 2 (b) are front views showing one embodiment of a cassette used in the above-mentioned apparatus, with a cover removed,
It is a top view.

FIG. 3 is a configuration diagram showing one embodiment of the gas measuring device of the present invention.

FIGS. 4 (a) and 4 (b) are diagrams showing the operation of the above-described device, with the detection area enlarged.

[Explanation of symbols]

 Reference Signs List 4 cassette holder 7, 8 reel 9 gas detection tape 10 window 10a, 10b edge 12 guide portion 16 cassette 20 measuring head 21 contact portion 21a, 21b side surface 22 gas inlet 23 gas outlet 24 opening 25 optical density sensor

Continued on the front page F term (reference) 2G042 AA01 BD20 CA10 CB01 DA08 FB07 HA07 2G054 AA01 CA30 EA05 FA02 FA15 FA28 FA39 FB02 FB03 GE02 JA11

Claims (3)

[Claims] 1. A cassette containing a gas detection tape that changes optical density in response to a measurement gas and having a window in a measurement area, and an opening for making gas contact with the measurement area of the gas detection tape are provided. A tape-type gas measuring device comprising a contact portion and a measuring head containing a means for detecting the optical density in opposition to the opening, wherein the window is formed, at least an unused area side of the gas detecting tape. A tape-type gas measuring device in which a side surface of the contact portion is in contact with an edge portion of the gas measuring device. 2. The tape-type gas measurement device according to claim 1, wherein the edge portion is formed as a slope that expands outward, and a side surface of the contact portion has a slope that matches the slope. 3. The tape-type gas measurement device according to claim 1, wherein narrow portions are formed on both sides of the window.