JPH07294458A - Contained sulfur measuring device for rubber sheet - Google Patents

Abstract

PURPOSE:To provide a contained sulfur measuring device for a rubber sheet by which contained sulfur can be measured without stagnating a manufacturing process. CONSTITUTION:An X-ray source to radiate an X-ray to cause fluorecent reaction on sulfur and an X-ray detector to detect and count this fluorescent X-ray are arranged at a prescribed microscopic clearance to a rubber sheet surface in a rubber sheet molding line to carry this rubber sheet 2 in the long size direction by continuously molding sulfur-mixed raw material rubber in a sheet shape, and a concentration measuring part 8 is arranged to find the sulfur containing concentration of the rubber sheet from this counting dosage.

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 content of sulfur in a rubber sheet produced by blending sulfur,
The present invention relates to an apparatus for measuring contained sulfur in a rubber sheet, which enables measurement without delaying the manufacturing process.

[0002]

2. Description of the Related Art Rubber products such as tires have desired properties by containing sulfur or the like. In order to make a rubber product contain sulfur, a step of mixing sulfur into the raw material rubber is required. Taking the case of a tire as an example, there is a step of first adding sulfur, carbon black, and other chemicals to the raw material rubber and kneading, and then there is a step of continuously forming the kneaded raw material rubber into a sheet. This rubber sheet is stretched from roller to roller and conveyed in the lengthwise direction, and is discharged after undergoing steps such as cooling during the conveyance. The tire is formed by reworking and shaping this rubber sheet and then curing it by heat treatment.

Since important properties such as the hardness of the tire depend on the sulfur content, it is necessary to control the sulfur content. For that purpose, it is necessary to measure the sulfur content of the rubber sheet before shaping it into a tire. Conventionally, a part of a rubber sheet is punched out to obtain a sample, the sample is burned, and the combustion gas is subjected to gas analysis to measure the contained sulfur, or an elasticity test of the rubber is performed after a vulcanization reaction.

[0004]

By the way, in the conventional measuring method, the work of punching out the sample is required. This work is done by people. It is desired to save labor and time required for punching work, and to improve efficiency.

Further, since it takes a long time to carry out tests such as sample combustion and gas analysis of combustion gas, it takes a long time to obtain an analysis result. Since the rubber sheet cannot be subjected to the next step until the analysis result is obtained, the rubber sheet becomes stagnant and the efficiency becomes poor in terms of time. Then, a space for accumulating the rubber sheets is required, and the spatial efficiency becomes poor.

Therefore, an object of the present invention is to solve the above-mentioned problems and to provide an apparatus for measuring sulfur contained in a rubber sheet, which enables measurement without delaying the manufacturing process.

[0007]

In order to achieve the above object, the present invention provides a rubber sheet forming line for continuously forming a raw material rubber mixed with sulfur into a sheet shape and conveying the rubber sheet in a longitudinal direction. , An X-ray source that irradiates sulfur with an X-ray that causes a fluorescent reaction, and an X-ray that detects and counts this fluorescent X-ray
The line detector is arranged at a predetermined minute gap from the surface of the rubber sheet, and a concentration measuring unit for determining the sulfur-containing concentration of the rubber sheet from the counted dose is provided.

The movement of the rubber sheet in the direction intersecting the rubber sheet surface may be restricted near the X-ray source and the X-ray detector.

The X-ray source and the X-ray detector may be housed in a shielding box in which an atmosphere that easily transmits X-rays is maintained.

A comparing section may be provided for comparing the measured concentration measured by the concentration measuring section with a predetermined standard concentration, and a marking section may be provided for marking the rubber sheet when the measured concentration deviates from the standard concentration.

The X-ray source and the X-ray detector may be configured to operate at two or more locations in the width direction of the rubber sheet.

The X-ray source may emit titanium characteristic X-rays, and the X-ray detector may detect sulfur fluorescent X-rays.

The concentration measuring unit stores the count dose / concentration characteristic previously obtained from a rubber sheet whose sulfur content is known,
The sulfur content concentration of an unknown rubber sheet may be calculated based on this characteristic.

Further, a cooling liquid tank for submerging the rubber sheet coming out from the sheeting roll in a cooling liquid is connected to a seating roll for continuously forming a raw material rubber mixed with sulfur into a sheet shape. A shielding box whose top is closed and whose bottom is opened in the cooling liquid is provided, and a conveyance roller that raises the rubber sheet above the cooling liquid surface is provided in this shielding box, and the rubber sheet that is raised above the cooling liquid surface is also provided. An X-ray source for irradiating X-rays that cause a fluorescent reaction to sulfur and a X-ray detector for detecting and counting the fluorescent X-rays are arranged at a predetermined minute gap with respect to the surface, and a rubber sheet is obtained from the counted dose. A concentration measuring unit for determining the sulfur-containing concentration of is provided.

[0015]

It is known that sulfur emits fluorescent X-rays in other specific wavelength bands when it is irradiated with X-rays in a specific wavelength band. The dose of fluorescent X-rays corresponds to the amount of sulfur. A method of utilizing this characteristic to measure the amount of sulfur is known as fluorescent X-ray analysis. The present invention is to provide an X-ray source and an X-ray detector in a rubber sheet forming line to measure the sulfur content concentration of the rubber sheet online.
However, X-rays in the above-mentioned wavelength band are easily absorbed by the object to be measured and the atmosphere, and it is a problem whether sulfur in rubber can be quantitatively detected.

Here, when the present applicant investigated the penetration depth of X-rays in the above wavelength band into the rubber material, it was several mm. On the other hand, the rubber sheet is usually several mm. The reflected depth of the fluorescent X-rays generated with respect to the incident X-rays is several tens of μm. Therefore, several tens of μm from the surface of the rubber sheet
X-rays can be obtained from sulfur at a depth of. It was also found that even if the atmosphere is air, if the transmission distance is short, the amount of absorption is small and measurement is possible. It was experimentally confirmed that the counted dose of fluorescent X-rays has a one-to-one correspondence with the sulfur content.

With the above structure, the X-ray source and the X-ray detector are arranged with a predetermined minute gap from the rubber sheet surface. X-rays from the X-ray source pass through the atmosphere of a minute gap,
Penetrates most of the depth of the rubber sheet. The fluorescent X-rays emitted from the sulfur in the rubber sheet pass through the atmosphere of the minute gap and are counted by the X-ray detector. Since this counted dose has a one-to-one correspondence with the sulfur content, the sulfur content is quantified. Since the rubber sheet is conveyed in the lengthwise direction, the measurement can be performed substantially continuously in the lengthwise direction.

When the rubber sheet is conveyed in the lengthwise direction, vibration may appear in the direction intersecting the surface of the rubber sheet. This vibration changes the minute gap and changes the amount of X-rays transmitted in the atmosphere, which is not preferable. By restricting the movement of the rubber sheet in the direction intersecting the rubber sheet surface in the vicinity of the X-ray source and the X-ray detector, the transmission distance in the atmosphere can be stabilized.

As described above, the measurement can be performed even if the atmosphere is air, but it is ideal to perform the measurement in vacuum in order to eliminate the absorption of X-rays. However, it is not economical to place a vacuum device on the rubber sheet forming line. Therefore, the X-ray source and the X-ray detector are housed in a shielding box in which an atmosphere that easily transmits X-rays is maintained. Here, the atmosphere that easily transmits X-rays means a high vacuum, a low vacuum, or a gas atmosphere. This reduces the absorption of X-rays and improves the measurement accuracy.

By providing a comparison unit for comparing the measured concentration measured by the concentration measuring unit with a predetermined standard concentration, it is possible to judge the quality of the rubber sheet and evaluate the quality based on the sulfur content concentration. Then, by providing a marking portion for marking the rubber sheet when the measured concentration deviates from the standard concentration, the evaluation result is marked on the rubber sheet, so that only defective products or defective portions can be easily processed in the subsequent process. Can be excluded.

If the rubber sheet has only one measurement point, even if the measurement can be performed substantially continuously over the lengthwise direction, only the same measurement point can be measured in the width direction. When the raw material rubber mixed with sulfur is continuously molded into a sheet shape, it is possible that the concentration is uneven in the width direction. If the X-ray source and the X-ray detector are configured to be able to operate at two or more locations in the width direction of the rubber sheet, it is possible to detect the concentration deviation in the width direction.

When sulfur is irradiated with titanium characteristic X-rays, sulfur emits sulfur fluorescent X-rays in a wavelength band different from this, and sulfur fluorescent X-rays are emitted.
The X-ray has a different wavelength band from the fluorescent X-rays from other substances. Therefore, if the X-ray source emits titanium characteristic X-rays and the X-ray detector detects sulfur fluorescent X-rays, only sulfur can be specified and the amount can be measured.

Since it has been experimentally confirmed that the counted dose of the fluorescent X-rays has a one-to-one correspondence with the sulfur content, the concentration measurement part was obtained from a rubber sheet having a known sulfur content in advance. If the count dose / concentration characteristic is stored, the sulfur content concentration of the unknown rubber sheet can be obtained by applying the count dose of the unknown rubber sheet to this count dose / concentration characteristic.

The sulfur concentration in the rubber sheet molding line can be measured in any step from sheet molding to payout, but it is important to maintain the measurement atmosphere while conveying the rubber sheet in the longitudinal direction. This cooling process is used for the configuration in which a cooling liquid tank that dives the rubber sheet coming out of the sheeting roll into the cooling liquid is connected to a sheeting roll that continuously forms raw rubber mixed with sulfur into a sheet shape. Then, the sulfur concentration should be measured. Specifically, by providing a shielding box in which the upper part is closed and the bottom part is opened in the cooling liquid in the cooling liquid tank, the space above the cooling liquid surface in the shielding box is shielded from outside the shielding box. The rubber sheet is raised on the cooling liquid surface by the conveying roller. Even when the rubber sheet is conveyed in the lengthwise direction, the rubber sheet is submerged in the cooling liquid, so that no gas enters and leaves the shielding box and a constant atmosphere is maintained. By arranging the X-ray source and the X-ray detector in the shielding box, the measurement atmosphere can be maintained and the measurement can be performed.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a diagram of a rubber sheet molding line equipped with the sulfur-containing measuring apparatus of the present invention. At the uppermost stream of the line, a sheeting roll 3 for continuously molding the raw material rubber 1 mixed with sulfur into a rubber sheet 2 having a thickness of 10 mm is provided. A transport roller 4 is provided downstream of the sheeting roll 3.
Are sequentially provided to convey the rubber sheet 2 in the longitudinal direction. A dusting liquid tank 5 for the step of applying the release agent and a batch-off machine 6 for the cooling step and adjusting the payout amount are provided in the middle thereof. The sensor unit 7 of the sulfur-containing measuring device is provided above the conveying roller 4 in front of the dusting liquid tank 5 so as to be movable in the width direction of the rubber sheet 2. The sensor unit 7 houses an X-ray source and an X-ray detector in a shielding box. The concentration measuring unit 8 is provided outside the drawing. The concentration measuring unit 8 stores a count dose / concentration characteristic previously obtained from a rubber sheet having a known sulfur-containing concentration, and obtains the sulfur-containing concentration of an unknown rubber sheet based on this characteristic.

FIG. 2 shows the details of the sensor section. X
The radiation source 21 is an X-ray tube that generates titanium characteristic X-rays.
The line detector 22 is a proportional counter equipped with an X-ray filter so as to detect only sulfur fluorescent X-rays. The X-ray source 21 and the X-ray detector 22 are arranged at a predetermined minute gap with respect to the rubber sheet surface, and are inclined at a predetermined angle with respect to the rubber sheet surface. The vertical distance d between the X-ray source 21 and the X-ray detector 22 is preferably 10 mm or less, and here, 5.5 m.
It is set to m.

The movement of the rubber sheet 2 in the direction intersecting the rubber sheet surface is restricted so that the vertical distance d does not fluctuate near the X-ray source 21 and the X-ray detector 22. For this purpose, a member such as a spacer may be inserted in the minute gap, but in this embodiment, the member for restricting the motion is not provided specially, but the motion is originally restricted due to the tension. The vicinity of the transport roller 4 is used. That is, the sensor unit 7 is provided above the transport roller 4 of the batch-off machine 6 to regulate the vertical movement of the rubber sheet in the sensor unit 7. As described above, the method of attaching the sensor unit 7 to the location where the movement of the rubber sheet is originally restricted, such as in the vicinity of the conveying roller 4, is effective in the case where a sulfur-containing measuring device is added to the existing rubber sheet molding line. is there.

FIG. 3 shows the details of the shielding box. Figure 3
The shielding box 31 of (a) is a shielding box 31 having an open bottom, and the rubber sheet 2 covers the opening. The shielding box 32 in FIG. 3B is a shielding box 3 having a substantially closed structure.
2 and only the X-ray transmitting portion 33 is a perforated or thin polymer film window. In either configuration,
The shielding boxes 31 and 32 are filled with gas or depressurized. It is desirable that the gas has a high transmittance for X-rays used for measurement and that there is no fluorescent action by X-rays, and generally, a light gas satisfies this condition. For safety, it is desirable that they are incombustible and inert. Therefore, helium is used here. Shield box 31,
32 has a structure in which at least the upper part is sealed so that helium does not escape.

The measurement atmosphere is ideally a vacuum, but any atmosphere that allows X-rays to easily pass therethrough may be used, and the structure for maintaining the atmosphere in the shielding boxes 31 and 32 is used as described above. In addition, the measurement can be performed without opening the shielding box to the atmosphere, and a gas such as helium may be blown to make the measurement atmosphere only at a necessary place.

FIG. 8 shows an example of a rubber sheet molding line different from that shown in FIG. At the uppermost stream of the line, a sheeting roll 3 for continuously forming a raw material rubber mixed with sulfur into a sheet shape is provided. A conveying roller 4 is sequentially provided downstream of the sheeting roll 3 to convey the rubber sheet 2 in the lengthwise direction. A cooling liquid tank 81 for submerging the rubber sheet 2 coming out of the sheeting roll 3 in the cooling liquid W is provided in the middle thereof.

In the cooling liquid tank 81, there is provided a shielding box 82 partially immersed in the cooling liquid W. This shielding box 82
Has a closed top and a bottom open to the coolant W. In the cooling liquid tank 82, a pair of conveying rollers 4a is provided in the cooling liquid W, and a pair of conveying rollers 4b is provided on the surface of the cooling liquid. These transport rollers 4a, 4b
The rubber sheet 2 is stretched over the sheet, the rubber sheet 2 coming out from the sheeting roll 3 once dives in the cooling liquid W, is raised to the cooling liquid surface in the shield box 82, and dives in the cooling liquid W again. It is adapted to be sent out of the cooling liquid tank 81. In the shielding box 82, the X-ray sources 21 and X already described
A sensor unit 7 that houses the line detector 22 is provided.
The shielding box 82 is filled with helium gas.

The computer 83 comprises a concentration measuring unit 8 for obtaining the sulfur-containing concentration of the rubber sheet from the counted dose and a comparing unit 84 for comparing the measured concentration measured by the concentration measuring unit 8 with a predetermined standard concentration. The shielding box 82 is provided with a marking unit 85 that marks the rubber sheet 2 when the measured concentration deviates from the standard concentration.

The marking unit 85 may be provided outside the shielding box 82.

Next, the operation of the embodiment will be described.

FIG. 6 shows energy spectra of titanium characteristic X-rays and sulfur fluorescent X-rays. The titanium characteristic X-rays emitted from the X-ray source 21 penetrate into the rubber sheet to a depth of 7 mm and are saturated. Part of the titanium characteristic X-rays excites sulfur in the rubber sheet, and the excited sulfur emits sulfur fluorescent X-rays. The amount of sulfur X-ray fluorescence is almost proportional to the amount of sulfur. The remaining titanium characteristic X-rays are scattered. The X-ray detector 22 is irradiated with sulfur fluorescent X-rays and titanium characteristic X-rays, but since the X-ray detector 22 is equipped with an X-ray filter, it detects only sulfur fluorescent X-rays. Note that the sulfur content concentration can be measured even when the X-ray detector 22 detects the sulfur fluorescent X-rays and the titanium characteristic X-rays. The X-ray detector 22 outputs the counted dose representing the amount of sulfur fluorescent X-rays to the concentration measuring unit 8.

FIG. 7 shows the count dose / concentration characteristics stored in the concentration measuring unit 8. The horizontal axis represents the sulfur content of the rubber sheet, and the vertical axis represents the count dose. This counted dose / concentration characteristic is obtained by measuring the concentration of a rubber sheet whose sulfur content is known in advance. Since the counted dose has a one-to-one correspondence with the sulfur content (concentration), the concentration can be obtained by giving the counted dose. The concentration measuring unit 8 obtains the sulfur content concentration from the count dose of the unknown rubber sheet obtained by the X-ray detector 22.

In the rubber sheet molding line equipped with the sulfur-containing measuring apparatus shown in FIG. 1, the measurement is performed almost continuously as the rubber sheet 2 is conveyed in the longitudinal direction, so that the manufacturing process is not delayed. You will be able to measure.

A structure for operating the X-ray source and the X-ray detector at two or more positions in the width direction of the rubber sheet will be described with reference to FIGS. 4 and 5.

The example shown in FIG. 4A is an example in which the sensor portion 7 containing the X-ray source and the X-ray detector is movable in the width direction of the rubber sheet. The black circles are the measurement points.
As the rubber sheet is conveyed in the lengthwise direction, the sensor portion 7 moves in the width direction, so that the measurement point moves the rubber sheet 2 obliquely as shown in FIG. 4B. It is possible to measure the entire width of the rubber sheet 2 with one sensor unit 7.

The example shown in FIG. 5A is an example in which a plurality of sensor portions 7 for accommodating an X-ray source and an X-ray detector are provided and fixed in the width direction of the rubber sheet 2. The black circles are the measurement points. As the rubber sheet 2 is conveyed in the longitudinal direction, FIG.
As shown in (b), each measurement point moves the rubber sheet 2 in the longitudinal direction. Since the sensor unit 7 is fixed, a moving mechanism is unnecessary. Further, it is possible to perform parallel measurement at a plurality of points at the same time.

Alternatively, each sensor unit 7 may be moved in the width direction of the rubber sheet 2 for measurement.

In the structure of FIG. 8, the rubber sheet 2 is raised on the cooling liquid surface by the conveying rollers 4a and 4b. A scraper 4c for removing the aqueous solution (containing lime) attached in the dusting tank is attached between the rollers 4a and 4b. This is to prevent X-ray absorption. Even when the rubber sheet 2 is conveyed in the lengthwise direction, the rubber sheet 2 is submerged in the cooling liquid W, so that no gas enters and leaves the shielding box 82 and a constant atmosphere is maintained. By disposing the X-ray source 21 and the X-ray detector 22 in the shielding box 82, the measurement atmosphere can be maintained and the measurement can be performed.

The concentration measuring unit 8 in the computer 83 obtains the sulfur-containing concentration of the rubber sheet from the counted dose obtained by the sensor unit 7. The comparing section 84 compares the measured density measured by the density measuring section 8 with a predetermined standard density. A rubber sheet used for an ordinary tire has a sulfur content of 5% or less, and an accuracy of 0.1% is required in manufacturing. Therefore, the standard concentration is 0.1 above and below the concentration to be manufactured.
Set to%. When the measured concentration deviates from the standard concentration, the marking unit 85 marks the rubber sheet 2. Since the labeling unit 85 is placed immediately downstream of the sensor unit 7,
The mark can indicate a defective portion of the rubber sheet 2. The marking may be provided on the upper surface or the side edge of the rubber sheet 2. When applied to the side edges, the rubber sheets 2 can be recognized from the side even if they are stacked after being dispensed. When applied on the upper surface, the marker applying unit 85 moves in the width direction together with the sensor unit 7, and the defective position can be specified in the width direction. In any case, since the evaluation result is marked on the rubber sheet 2, it is possible to easily exclude only defective products or defective parts in a later step.

[0045]

The present invention exhibits the following excellent effects.

(1) Since the X-ray source and the X-ray detector are provided in the rubber sheet molding line, the sulfur content concentration of the rubber sheet can be measured online, and the manufacturing process is not delayed.

(2) It is not necessary to punch or burn the rubber sheet, and the measurement can be performed automatically, so that the production line can be labor-saving.

[Brief description of drawings]

FIG. 1 is a perspective view of a rubber sheet molding line equipped with an apparatus for measuring sulfur content according to an embodiment of the present invention.

FIG. 2 is a side view of the sensor unit of the present invention.

FIG. 3 is a sectional view of the shielding box of the present invention.

FIG. 4 is a plan view of the rubber sheet of the present invention.

FIG. 5 is a plan view of the rubber sheet of the present invention.

FIG. 6 is an X-ray energy spectrum diagram of the present invention.

FIG. 7 is a counting dose / concentration characteristic diagram of the present invention.

FIG. 8 is a block diagram of a rubber sheet molding line equipped with an apparatus for measuring sulfur content according to another embodiment of the present invention.

[Explanation of symbols] 2 rubber sheet 3 sheeting roll 4, 4a, 4b transport roller 7 sensor unit 8 concentration measuring unit 21 X-ray source 22 X-ray detector 31, 32, 82 shielding box 84 comparing unit 85 labeling unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shiro Yajima 3-15-1, Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries Co., Ltd. Toni Technical Center (72) Inventor Yoshinori Kawasaki 3-chome, Toyosu, Koto-ku, Tokyo No. 1-15 Ishikawajima Harima Heavy Industries Co., Ltd. Toni Technical Center (72) Inventor Yumi Ogata 3-15-15 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries Co., Ltd. Toji Technical Center

Claims (8)

[Claims] 1. An X-ray for irradiating a rubber sheet forming line for continuously forming a raw material rubber mixed with sulfur into a sheet shape and conveying the rubber sheet in a longitudinal direction with an X-ray for causing sulfur to cause a fluorescent reaction. A source and an X-ray detector for detecting and counting the fluorescent X-rays are arranged at a predetermined minute gap with respect to the rubber sheet surface, and a concentration measuring unit for determining the sulfur content concentration of the rubber sheet from the counted dose is provided. An apparatus for measuring sulfur contained in a rubber sheet, which is characterized in that: 2. An apparatus for measuring sulfur contained in a rubber sheet according to claim 1, wherein movement of the rubber sheet in a direction intersecting the rubber sheet surface is restricted in the vicinity of the X-ray source and the X-ray detector. 3. The sulfur contained in the rubber sheet according to claim 1, wherein the X-ray source and the X-ray detector are housed in a shielding box in which an atmosphere that easily transmits X-rays is maintained. apparatus. 4. A comparison unit for comparing the measured concentration measured by the concentration measuring unit with a predetermined standard concentration and a marking unit for marking the rubber sheet when the measured concentration deviates from the standard concentration. The sulfur content measuring device for rubber sheet according to any one of claims 1 to 3, characterized in that. 5. The rubber sheet according to claim 1, wherein the X-ray source and the X-ray detector are configured so as to be operable at two or more locations in the width direction of the rubber sheet. Sulfur measuring device. 6. The X-ray source emits titanium characteristic X-rays,
The sulfur content measuring device for rubber sheet according to any one of claims 1 to 5, wherein the X-ray detector is configured to detect titanium characteristic X-rays and sulfur fluorescent X-rays. 7. The concentration measuring unit stores the count dose / concentration characteristic previously obtained from a rubber sheet having a known sulfur content concentration, and determines the sulfur content concentration of an unknown rubber sheet based on this characteristic. The sulfur content measuring device for a rubber sheet according to claim 1. 8. A cooling liquid tank for submerging the rubber sheet coming out of the sheeting roll into a cooling liquid is connected to a seating roll for continuously forming a raw material rubber mixed with sulfur into a sheet, and the inside of the cooling liquid tank is connected. A shielding box whose top is closed and whose bottom is opened in the cooling liquid is provided, and a conveyance roller that raises the rubber sheet above the cooling liquid surface is provided in this shielding box, and the rubber sheet that is raised above the cooling liquid surface is also provided. An X-ray source for irradiating X-rays that cause a fluorescent reaction to sulfur and a X-ray detector for detecting and counting the fluorescent X-rays are arranged at a predetermined minute gap with respect to the surface, and a rubber sheet is obtained from the counted dose. An apparatus for measuring sulfur content in a rubber sheet, comprising a concentration measuring unit for determining the sulfur content concentration of.