JP3485238B2 - Tape type gas concentration measurement device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas concentration measuring device using a gas detection tape impregnated with a chemical agent that causes a color reaction with a test gas.

[0002]

2. Description of the Related Art A gas concentration measuring device using a gas detecting tape in which a tape-shaped carrier is impregnated with a chemical agent that develops a color reaction with a test gas is usually wound in a certain length and housed in the device. It is configured to be drawn out to a sampling region at regular intervals to react with a gas, and a reaction mark generated at this time is optically detected and converted into an electric signal. With this device, the concentration of extremely dilute gas can be measured by adjusting the sampling time of the test gas, and it has a certain level of recordability, so it is widely used for continuous monitoring in the environment. It is used.

In addition, when replacing the tape, it is not only necessary to pass one end of the tape through the sampling area and fix it on the take-up reel, but it may also be discolored by sweat or the like depending on the chemicals used. There are problems such as vandalism. In order to solve such a problem, the applicant of the present invention stores a gas detection tape in a cassette as shown in Japanese Patent Laid-Open No. 8-94529, and also a measuring head and a suction means so as to sandwich a tape transport path. Tape type including a suction head communicating with the suction head, a paper feed mechanism that intermittently feeds the gas detection tape, and a head drive mechanism that interlocks with the paper feed mechanism and relatively separates the measurement head and the suction head from each other. A gas concentration measuring device was proposed.

[0004]

According to this, since the gas detection tape can be loaded on the measuring head through the cassette, it is possible to prevent discoloration of the tape and rough skin, but to measure the cassette by a fixing means such as a screw. There is a problem that it is necessary to mount it on the device, and the attaching / detaching operation is relatively complicated. The present invention has been made in view of the above problems, and an object of the present invention is to provide a tape-type gas concentration measuring device capable of exchanging a cassette loaded with a gas detection tape by a simple operation. That is.

A second object of the present invention is to provide a tape type gas concentration measuring device capable of easily checking the optical means for measuring the optical concentration of the gas detecting tape.

[0006]

In order to solve such a problem, according to the present invention, there is provided a cassette holder which is vertically movable on the upper surface of a main body case and also serves as a positioning member for a cassette containing a gas detection tape. A winding motor that drives a winding shaft that engages with the reel of the cassette to wind the tape by a certain amount, and a position that is arranged on a surface that faces the tape outlet of the cassette and that faces the suction head.
Is equipped with a measurement chamber, and the axis is perpendicular to the gas detection tape.
The holes are drilled so that they coincide with each other and communicate with the measurement chamber.
The light receiving element housed in the hole and the front
That of a plurality of through holes formed so as to communicate with the measurement chamber
The light-emitting element housed in each is connected to the measurement chamber.
A measuring head having a through hole of the test gas extraction necessity which is urchin formed, are movably arranged relative to the measuring head to the opposite side across the tape feeding path, from the pump unit
The suction head on which the suction force acts and the gas detection table
A pressing roller and a pinch roller, which are arranged with the pump interposed therebetween,
A cam surface that is rotationally driven by a driving unit to move the suction head forward and backward with respect to the measurement head, and the pinch roller.
A cam plate formed with a cam surface for advancing and retracting the pressing roller with respect to
With the winding motor in pressure contact with the pinch roller,
Rotate to measure a new area of the gas detection tape
Face the head, then rotate the cam plate to
The pressing roller is retracted from the pinch roller, and
With the suction head sandwiching the detection tape,
It is configured to move to the position where it makes elastic contact with the
It

[0007]

When the cassette is loaded into the cassette holder and pushed down, the cassette engages with the winding shaft. When the cam plate rotates in this state, the suction head makes elastic contact with the measurement head via the detection tape to enable measurement. Also, for turning the cam plate
The pressure roller is retracted from the pinch roller and suctioned.
Elastically contact the measuring head with the head sandwiching the detection tape.
Unused position due to the contact of the roller to move it to the position
Prevents discoloration of the area and prevents detection errors.

[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 the present invention, in which a main body case 1 has a front surface 2 as a panel surface, a display means 3, a control switch 4 and the like, and an upper surface 5.
Is used as a cassette housing, and a cassette holder 7 that can be moved up and down by a link mechanism 6 is provided here.

FIGS. 2, 3 and 4 show an embodiment of a mechanism for pulling out the gas detection tape of the cassette loaded in the cassette holder to the measuring head, and at a position facing the tape reel of the cassette A. , The idler 8 and the winding shaft 9 are arranged, and the holder 7 is pushed into the main body case 1 (FIG. 1A), the reels C and D of the cassette A are
Is adapted to engage with. A winding motor 11 (FIG. 4) is connected to the lower end of the winding shaft 9 via a train wheel 10.

As shown in FIG. 3, the measuring head 12 is located on the surface of the cassette A facing the cover E of the tape withdrawal port, and a cam to be described later is located at the cassette side across the tape transport path. A suction head 14 that moves back and forth perpendicularly to the transport path is arranged by the plate 13.

Further, as shown in FIG.
As shown in FIG. 5, a pressing roller 16 is arranged which is advanced and retracted by the cam plate 13 and presses the tape against the pinch roller 15. A code plate 17 for detecting the rotation amount is attached to the lower end of the pressing roller 16.

As shown in FIG. 5, the cam plate 13 is fixed to a shaft 19 of a geared motor (not shown), and in the tape drawing step, the shaft 21 also serving as a flow path of the suction head 14 is formed on the cassette A side by the first cam surface 20. The second cam surface 22 moves the pressing roller 16 back to the pinch roller 15
Further, in the detection process, the pressing roller 16 is retracted from the pinch roller 15, while the suction head 14 is moved to the measuring head 12 side.

Further, detection pieces 23, 24, 25 are formed on the outer circumference of the cam plate 13, and when the cam plate 13 is rotated by a predetermined amount, the detection pieces 23, 24, 25 output signals. Photo interrupters 26, 2
7, 28 are arranged. In the figure, reference numeral 29 is a projection for opening and closing provided at a position facing one end of the cover E, reference numeral 30 is a window through which the link 6 penetrates, and reference numeral 31 is a lever for instructing the pressing roller 16. The respective cam followers are shown.

Next, the measuring head 12 will be described. As shown in FIG. 3, the axis L1 perpendicular to the detection tape T
A light-receiving element 33 is provided on the upper side, and a plurality of light-emitting elements are provided at equal intervals so as to surround the light-receiving element 33. In this embodiment, three light-emitting diodes 34, 34, 34 irradiate the light-receiving area of the light-receiving element 33, and The holder 36 is arranged so that the light from the same enters the light receiving element 33 with almost the same amount of light.
The measurement chamber 37 is formed in a region facing the irradiation surface.

The measuring chamber 37 is connected to a dust removing filter 39 through a through hole 38 similar to the mounting hole of the light emitting element 34, and the other end of the filter 39 is connected to the measuring environment by a flow path. The suction head 14 has a through hole 21a of the shaft 21.
Is connected to a pump unit (not shown) via the tape, and is configured to suck the air in the environment to be measured through the tape T.

In this embodiment, when the cassette holder 6 and the main body case 1 are unlocked, the cassette A is loaded in the cassette holder 6 and the holder 6 is set in the case main body 1, the cassette A is set to a predetermined size. The cover E is pushed up and opened by the projection 29 in the process of being positioned in the position, and the reels C and D engage with the idler 8 and the take-up shaft 9 at the stage where the cover E is lifted and opened to various positions. To do.

When the power is turned on, the cam plate 13 is rotated by a geared motor (not shown) and is rotated until the detection piece is positioned at the first photo interrupter 26, and the cam plate 1 is rotated.
Position 3 in the home position.

Further, the cam plate 13 is rotated to move the detection piece to the second position.
When it is positioned on the photo interrupter 27, the shaft 21 is pushed by the first cam surface 20 of the cam plate 13 and retracts from the detection tape T, while the pressing roller 16 is pressed against the pinch roller 15 by the second cam surface 22. It

In this state, the take-up motor 11 rotates and stops when the pressing roller 16 reaches a certain amount, that is, an amount that allows a new area of the detection tape T to face the measuring head 12.

Then, the cam plate 13 is moved by a predetermined amount, that is, the pressing roller 16 is retracted from the pinch roller 15, and instead the suction head 14 is rotated to a position where it is elastically contacted with the measuring head 12 via the detection tape T. By releasing the elastic contact between the pinch roller 15 and the pressing roller 16 after the paper feeding operation, it is possible to prevent the unused areas from being discolored by the rollers 15 and 16.

When the new area of the detecting tape T is set on the measuring head 12 as described above, the optical density measuring sequence is started. In this sequence, the light emitting elements 34, 34, 34 are sequentially turned on, and it is detected whether or not the amount of light from the light receiving element 33 changes according to the number of lighting. In this step, if the change in the signal level of the light receiving element 33 is not proportional to the number of light emitting elements 34, 34, 34, at least one of the plurality of light emitting diodes 34, 34, 34 fails and the tape T Since the amount of the reflected light from is decreasing, an alarm is issued to prompt the user to inspect the measuring head 12.

When the pump unit is operated at the stage where the function check of the light receiving element 33 and the light emitting element 34 is completed, the gas to be measured is sucked into the measuring head 12 through the through hole 21a of the shaft 21, and the detection tape T is removed. It passes and is discharged to the outside.

The test gas reacts with the drug on the detection tape T in the process of passing through the detection tape T to form a reaction mark having an optical density corresponding to the concentration on the surface of the detection gas.
When a predetermined sampling time has elapsed, the pump unit is stopped and sampling is completed.

The light emitted from the light emitting diodes 34 and 35 is absorbed and reflected according to the optical density of the reaction mark formed on the surface of the detection tape t, and is received by the light receiving element 33. The ratio of this signal and the signal detected immediately after feeding the tape, and the difference in optical density is detected from the difference,
The gas concentration is converted and displayed on the display means 3, and is also output to a monitor (not shown).

When the cam plate 13 is driven in the reverse direction and the detection piece is positioned on the second photo interrupter 27 at the time when the measurement for one sampling is completed in this way, the shaft 21 causes the first cam of the cam plate 13 to move. While being pushed by the surface and retracted from the detection tape T, the pressing roller 16 is pressed against the pinch roller 15 by the second cam surface 22.

In this state, the take-up motor 11 rotates and stops when the pressing roller 16 reaches the amount where a new area of the detection tape T can be opposed to the measuring head 12. The winding amount of the winding motor 11, for example, in the case of a pulse motor, the number of drive pulses in the case of a pulse motor correlates with the tape amount of the reel D in order to wind the tape T of a certain amount. The tape remaining amount or consumption amount of the cassette A can be detected by the rotation amount of 11. Therefore, even when a cassette in use is loaded or unloaded, the remaining amount of the tape T can be surely known.

Then, the cam plate 13 is rotated in the normal direction to retract the pressing roller 16 from the pinch roller 15 to release the contact between the pinch roller 15 and the pressing roller 16 and the tape T,
In addition, the suction head 14 is attached to the measuring head 12 via the tape T.
The test gas can be sucked by making elastic contact with.

When the new area of the detection tape T is set on the measuring head 12 as described above, the above-mentioned optical density measuring sequence is activated to start the next measuring operation.

[0029]

[Brief description of drawings]

1A and 1B are views showing an embodiment of a gas detecting tape type gas concentration measuring device of the present invention in a state where a cassette holder is housed and a state where it is pulled out, respectively.

FIG. 2 is a diagram showing a top surface structure of a detection unit of the same apparatus.

3A and 3B are a side view showing a structure of a detection region in the same apparatus and a front view showing an embodiment of a measuring head, respectively.

FIG. 4 is a side view showing a structure of a tape feeding area of the same apparatus.

FIG. 5 is a rear view showing the structure near the cam plate for controlling the operation of the above apparatus.

[Explanation of symbols]

1 body case 7 cassette holder 11 winding motor 12 Measuring head 13 Cam plate 14 Suction head 15 pinch rollers 16 pressure roller 17 code plate 19 Cam plate drive shaft 20 First cam surface 22 Second cam surface 33 Light receiving element 34 Light emitting element 37 Measuring room 38 Through-hole for intake of test gas A cassette E cover T gas detection tape

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-8-94529 (JP, A) JP-A-7-161104 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01N 31/22 121 G01N 21/78

Claims (3)

(57) [Claims] 1. A cassette holder which is provided on the upper surface of a main body case so as to be vertically movable and also serves as a positioning member for a cassette containing a gas detection tape, and a winding shaft which engages with a reel of the cassette is driven to drive the tape. A winding motor that winds a fixed amount of the tape , a measurement chamber that is arranged on the surface of the cassette facing the tape outlet, and that faces the suction head.
It is pierced to match the axis perpendicular to the scanning tape,
A light receiving element housed in a through hole communicating with the measurement chamber
So as to surround the through hole and communicate with the measurement chamber.
Luminescent element housed in each of a plurality of through holes formed in
Child and test gas formed so as to communicate with the measurement chamber
A measuring head having a through hole for taking in and a measuring head which are arranged so as to be able to move forward and backward with respect to the measuring head on both sides of the tape transport path so that suction force from the pump unit
The suction head that acts, and a pressing roller that is arranged with the gas detection tape interposed therebetween, and
And the pinch roller, the cam surface causes rotationally driven forward and backward the suction head relative to the measuring head by a driving means and
A cam plate formed with a cam surface for advancing and retracting the pressing roller with respect to the pinch roller , wherein the cam plate transforms the pressing roller into the pinch roller.
The gas is rotated by rotating the take-up motor under pressure.
With the new area of the detection tape facing the measuring head,
Then, by rotating the cam plate, the pressing roller is pushed
Of the suction head and the suction head.
Position where the measuring tape makes elastic contact with the measuring head
Tape-type gas concentration measuring device that moves up to . 2. The measuring head includes at least one light receiving element and a plurality of light emitting elements, and the light emitting elements are sequentially turned on at the beginning of measurement, and the light receiving element is operated by changing a level of a signal from the light receiving element. The tape type gas concentration measuring device according to claim 1, wherein the function of the element or the light emitting element is inspected. 3. The tape type gas concentration measuring device according to claim 1, wherein the tape remaining amount of the cassette or the tape consumption amount is determined based on the rotation amount of the motor when the tape is wound.