JP3440658B2 - Hose with wear sensing function - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hose with a wear detecting function.

[0002]

2. Description of the Related Art Muddy water generated in tunnel construction and the like is pumped up to the ground using an abrasion resistant hose. In the case of this wear-resistant hose, a wear-resistant inner rubber layer is formed, but if this wear-resistant inner rubber layer is completely worn, the hose may burst due to high internal pressure. It is necessary to replace the hose before that. For that purpose, it is necessary to know the life of the wear resistant hose.

A method that has been conventionally used as a method of knowing the life of a wear-resistant hose is a method of empirically calculating the life based on the usage time of the hose, the transport amount, and the like. However, this is an inaccurate calculation of the life expectancy, and the life is set shorter than the original life in order to replace the hose early in anticipation of safety in order to avoid the risk of bursting. There is no choice but to do that. In this case, naturally, the usage (consumption) of the hose increases, and the cost becomes high.

Therefore, there have been conventionally proposed means for detecting when the hose actually reaches the wear limit.
The main one is that the conductor is buried inside the hose,
When the wear amount of the hose reaches a certain wear amount, the buried conductor is exposed to cause a break in the conveyed product, and the hose life is known by detecting the break (for example, JP-A-5-272469). ).

[0005]

However, in this case, even if the hose is worn to the limit and the conductor is exposed, the conductor is not immediately broken, and thereafter, the hose is continuously used for a certain period of time and then the conductor is broken. Therefore, there is a problem that the sensitivity of wear detection is low and there is a problem that the wear detection timing is delayed.In some cases, even if the conductor is exposed, the conductor does not pull out the conductor from the inside of the hose and the wire is not broken. There is a problem that the limit may not be sensed.

In order to prevent this, when the conductor wire is made thin so that the wire is likely to be broken, even if the hose is not actually worn due to bending deformation of the hose or pressure applied to the hose, the conductor wire is not damaged. May cause a disconnection.

[0007]

The invention of the present application has been made to solve such a problem. Thus, the hose of the present invention is a hose that conveys a fluid having electrical conductivity, in which a pair of linear sensing elements made of a conductive material for the positive electrode and a negative electrode are located at the same radial position in the cross section of the hose. And is embedded at a position separated by a predetermined distance in the axial direction, and wear is sensed based on conduction between the pair of sensing bodies (claim 1).

According to another aspect of the present invention, in the hose of claim 1, the pair of the positive electrode and the negative electrode of the pair of sensing bodies are spirally wound in parallel with each other over the entire length of the hose. It is embedded in (2).

According to still another aspect of the present invention, there is provided a hose according to claim 1.
Or 2, an insulating rubber layer not containing carbon black as a reinforcing filler is provided outside the wear-resistant inner rubber layer in the cross section of the hose, and the pair of sensing bodies is provided inside the insulating rubber layer. It is embedded (claim 3).

According to still another aspect of the present invention, there is provided a hose according to claim 3.
In, the abrasion-resistant intermediate rubber layer is provided further outside the insulating rubber layer (claim 4).

[0011]

As described above, the invention of claim 1 is one in which a pair of positive and negative electrode sensing bodies are embedded in the hose. In the case of the hose of the present invention, when the hose wears from the inner surface side and the wear amount reaches a certain wear amount, the pair of sensing bodies is exposed. Here, the pair of sensing bodies are brought into conduction with each other using a conductive fluid, for example, water as a medium, and are in a state of forming a circuit. Therefore, if a voltage is applied between the pair of sensors, a weak current will flow through the sensors, and based on the current detection, it can be known that the hose has reached a certain wear amount, for example, the wear limit. .

In the case of the hose of the present invention, the wear is not sensed by the breakage of the sensing body, but the wear is sensed by bringing the pair of exposed sensing bodies into a conductive state through a fluid. As soon as the hose reaches a certain amount of wear, that is, when the pair of sensors are exposed, the wear can be sensed immediately. Therefore, the wear can be sensed with high sensitivity without causing a time delay in wear detection. .

Further, there is no inconvenience that the sensor is dragged out by a fluid such as mud without breaking the wire and the wear detection based on the wire disconnection is not performed, and the present invention detects wear by the wire breaking of the sensor. Not
Since the wear is sensed by the exposure itself of the sensor, the sensor can be made to have a high strength, and it is possible to avoid the inconvenience that the sensor is disconnected due to bending of the hose or the like.

Here, in the present invention, the sensing element is
It can be a plain weave of copper wire. As a result, the sensor can be made to have a high strength, and when the sensor is exposed, it can be in contact with a fluid over a wide area, increasing the sensitivity of wear detection. be able to.

According to a second aspect of the present invention, the pair of sensing members for the positive electrode and the negative electrode are embedded in a spiral shape in parallel with each other while keeping a constant distance over the entire length of the hose. The wear can be immediately sensed when any of the points along the longitudinal direction of the hose reaches the set wear amount.

Further, according to the present invention, since the sensor can be embedded in the hose by the same method as that of winding the reinforcing fiber, there is an advantage that the sensor can be embedded and the hose can be easily manufactured. .

In a third aspect of the present invention, an insulating rubber layer containing no carbon black is provided on the outer side of the wear-resistant inner rubber layer, and a pair of sensors are embedded in the insulating rubber layer. By doing this, it is possible to reliably prevent the pair of sensing bodies from becoming conductive through carbon black before the hose wears and the pair of sensing bodies is exposed, and the sensitivity is high. Wear detection can be performed.

According to a fourth aspect of the present invention, a wear-resistant intermediate rubber layer is provided further outside the insulating rubber layer. According to the present invention, the wear-resistant rubber layer is provided after the wear is sensed. There is enough time to completely wear it,
It is possible to ensure safety.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment in which the present invention is applied to a wear-resistant hose used for carrying muddy water containing mud during tunnel construction will be described in detail with reference to the drawings. FIGS. 1 and 3 show the cross-sectional structure of the wear-resistant hose. As shown in the figure, the wear-resistant hose has a hose body part from the inside to the wear-resistant inner surface rubber layer 10 and an insulating rubber on the outside thereof. The layer 12, the wear-resistant intermediate rubber layer 14, the fiber reinforcing layer 16, the embedded rubber layer 18, the fiber reinforcing layer 20, and the outer rubber layer 22 have a laminated structure. In this example, the thickness of each layer is as follows, that is, the inner rubber layer 10 has a thickness of 5 mm and the insulating rubber layer 12 has a thickness of 4 mm.
mm, the intermediate rubber layer 14 is 1 mm, and the outer rubber layer 22 is 2.
It has a thickness of 5 mm.

The inner rubber layer 10 is made of NR / BR rubber (black rubber) containing carbon black as a reinforcing filler, and the insulating rubber layer 12 contains carbon black as a reinforcing filler. NR / BR rubber (white rubber), the intermediate rubber layer 14 is made of the same material as the inner rubber layer 10, and the buried rubber layer 18 on the outer side thereof is made of carbon black-containing SBR rubber (black). The rubber) and the outer rubber layer 22 are made of NR / SBR rubber (black rubber) containing carbon black.

Reference numeral 24 is a spirally wound steel wire, which is embedded between the fiber reinforcing layers 16 and 20. The portion between the steel wires 24 and 24 is filled with the embedded rubber layer 18. The fiber reinforcing layers 16 and 20 are spirally wound high-strength polyester fibers (2 plies),
A required strength is given to the hose together with the steel wire 24.

In this example, an inner metal fitting 30 having a flange portion 30A and a nipple portion 30B having an outer peripheral surface which is uneven in the axial direction and a tubular outer metal fitting 32 are provided at the end of the hose body. It is fixed in a state of nipping the body in the radial direction.

In the present example, inside the insulating rubber layer 12, a pair of continuous linear sensors 2 for positive and negative electrodes are provided.
6 and 28 are embedded in a spirally wound state so as to be parallel to each other (see FIG. 3). These sensing elements 26, 28 are made of copper wire in a plain weave pattern,
The + pole sensing body 26 and the − pole sensing body 28 are arranged at a constant pitch L in the same radial position over the entire length of the hose so as to alternate in the axial direction of the hose and in a state of being separated from each other in the axial direction. It is buried so as to be eggplant.

As shown in FIG. 2, the sensor 26,
Strictly speaking, 28 is a bundle of 5 stainless steel wires with a wire diameter of 0.12 mm and 6 tinned copper wires, and 12 of them are plain woven, and are bonded inside the insulating rubber layer 12. It is buried. However portion located between the inner metal member 30 and the outer fitting 32, the fixed portion of the words fitting 30, 32 outer surface is coated with Teflon tube 34,
In that state, it is buried inside the insulating rubber layer 12.

As shown in FIG. 1, the positive electrode sensor 26 and the negative electrode sensor 28 are connected to a detector 36 outside the hose. A constant voltage is applied between the sensing bodies 26 and 28. The detector 36 includes a sensor 26,
An alarm sound (buzzer) is generated when a current flows between 28, or together with this, a lamp is lit to warn that the hose has reached the wear limit. still,
In this example, when the hose reaches the wear limit, the pair of sensors 26 and 28 are exposed so that the sensors 2 and 28 are exposed.
6,28 buried positions are selected.

In the case of the wear-resistant hose of this example, when the hose is worn from the inner surface side and the entire inner rubber layer 10 is worn, and the pair of sensing bodies 26 and 28 are exposed and brought into contact with the muddy water inside. The pair of sensing bodies 26 and 28 are brought into a conductive state via muddy water. That is, the circuit is in a closed state, and a weak current flows there. The detector 36 senses this weak current and sounds the buzzer or, together with this, lights the lamp to indicate to the user that the hose has reached the wear limit.

As described above, in the case of the hose of this example, the wear is not sensed by the disconnection of the sensing bodies 26, 28, and the pair of sensing bodies 26, 28 that have been exposed are brought into a conductive state via the carrier fluid. By doing so, it is possible to detect wear, so that when the hose reaches the wear limit, this can be detected immediately. That is, it is possible to detect wear with high sensitivity without causing a time delay in wear detection.

Further, there is no inconvenience that the sensing bodies 26, 28 are dragged out by the carrier fluid without being broken and the wear detection based on the breaking is not carried out, and the hose of this example has the sensing bodies 26, 28. To detect wear by the exposure of the sensor itself,
Can be made strong, and it is possible to avoid the inconvenience that the sensors 26 and 28 are disconnected due to bending of the hose or the like.

Further, in this example, since the pair of sensing members 26 and 28 for the positive electrode and the negative electrode are buried over the entire length of the hose, any position along the longitudinal direction of the hose is set to the set wear amount. The wear can be sensed immediately when it is reached.

Further, according to this example, the sensing bodies 26 and 28 can be embedded in the hose by the same method as that of winding the reinforcing fiber, and the burying work of the sensing bodies 26 and 28 and the hose manufacture can be facilitated. is there.

In addition, in this example, since the insulating rubber layer 12 containing no carbon black is provided and the pair of sensing bodies 26, 28 is embedded therein, the pair of sensing bodies 26, 28 are It is possible to surely avoid the state of being conductive from the beginning, and it is possible to perform wear detection with high sensitivity.

Further, since the abrasion-resistant intermediate rubber layer 14 is provided further outside the insulating rubber layer 12, it is sufficient until the abrasion-resistant rubber layer is completely worn and the risk of rupture occurs after the abrasion is sensed. There is time to spare and safety can be secured.

[0033] Other in hose end fitting 30, 32 is fixed, because it covers and protects the sensing element 26, 28 in the Teflon tube 34, fixing the bracket 30, 32
In part content can be prevented such cause rubber breakage based on the embedded sensing member 26, can be avoided such wear sensing based on the rubber breakage becomes inaccurate.

<Experimental Example> Next, the results of a wear sensing test using the above hose (diameter 300 mmφ, length 2 m) will be described below. The experiment was conducted as follows. That is, as shown in FIG. 4, at a position 300 mm from one end of the hose body, the rubber in the portion indicated by the broken line in the drawing is cut off to remove the pair of sensing bodies 26, 2
8 was exposed, and the both ends of the hose were closed with a closing jig, and the inside thereof was filled with industrial water at a predetermined pressure, and the electric resistance value between the pair of sensing bodies 26 and 28 was measured. The results are shown in Table 1.

However, in Table 1, the electric resistance value at the time of new article is the measured value when such rubber cutting is not performed, and the blank is the measurement value when the inside of the hose is empty. It is a value. Further, in the table, “A side” indicates the measured electric resistance value between the sensors 26, 28 extending from the end of the hose close to the rubber cut portion, and “B side” indicates the measured value at the opposite end. ing.

[0036]

[Table 1]

From the above results, the measured values are not so different between the state in which the internal pressure is applied to the hose and the state in which the internal pressure is not applied to the hose.
When the hose 28 is exposed and when the sensors 26 and 28 are not exposed, that is, when the hose reaches the wear limit and when the hose is new, the electric resistance value largely changes (about one to two digits). Therefore, it can be seen that the wear limit of the hose can be detected with high sensitivity.

Although the embodiment of the present invention has been described in detail above, this is merely an example. For example, in the present invention, it is possible in some cases to double the sensor bodies in the thickness direction of the hose with a predetermined gap, and to detect the wear amount stepwise according to the degree of wear of the hose. However, the present invention can be applied to a hose for pouring fresh concrete and other hoses, and various modifications can be made without departing from the scope of the invention.

[Brief description of drawings]

FIG. 1 is a view showing a cross-sectional structure of a main part of a hose with a wear detecting function according to an embodiment of the present invention.

2 is an enlarged cross-sectional view of an essential part of a metal fixture fixing portion in FIG. 1 and a diagram showing a configuration of a sensing body in FIG.

FIG. 3 is a perspective view showing the hose of FIG. 1 with a part thereof cut open.

FIG. 4 is an explanatory diagram of a test method when a wear sensing test is performed using the hoses of FIGS. 1 to 3.

[Explanation of symbols] 10 Inner rubber layer 12 Insulating rubber layer 14 Intermediate rubber layer 26,28 sensor 30 Inner bracket 32 Outer metal fittings 34 Teflon tube 36 detector

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16L 51/00-55/24 F16L 11/08 F16L 11/12 F17D 5/00

Claims (4)

(57) [Claims] 1. A hose for transporting a fluid having conductivity, wherein a pair of linear sensing elements made of conductive materials for + and − electrodes are provided at the same radial position in the hose cross section and in the axial direction. A hose with a wear detecting function, wherein the hose is embedded at positions separated by a predetermined distance, and wear is detected based on conduction between the pair of sensing bodies. 2. The pair of sensing members for the positive electrode and the negative electrode according to claim 1, wherein the pair of sensing members for the positive electrode and the negative electrode are embedded in the hose in a state of being spirally wound in parallel with each other over the entire length of the hose. A hose with a wear detection function. 3. The insulating rubber layer according to claim 1 or 2, wherein an insulating rubber layer containing no carbon black as a reinforcing filler is provided outside the wear-resistant inner rubber layer in the cross section of the hose. A hose with a wear detecting function, characterized in that the pair of sensors are embedded inside. 4. The hose with a wear detecting function according to claim 3, further comprising an abrasion-resistant intermediate rubber layer further outside the insulating rubber layer.