JP2938377B2 - Rubber sleeve and its wear detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber sleeve used for a pipe joint or a pinch valve in the field of storing, discharging, or transporting powder, liquid, or a mixture of liquid and powder. .

[0002]

2. Description of the Related Art Conventionally, a rubber sleeve used for a pinch valve or a joint of a pipe is subjected to an internal pressure when powder is stored or transported, so that a pressure-resistant design corresponding to the pressure is made. When rubber alone is not sufficient, the pressure resistance is maintained by reinforcing a reinforcing cord or cloth. If the inner rubber of the rubber sleeve wears and the wear progresses to the reinforcing portion, it bursts without enduring the pressure, and there is a risk of fluid loss and personal injury. Conventionally, color rubber is lined inside the rubber, and when the color rubber is exposed by visual inspection, it is replaced or a metal electrode is embedded inside the rubber to detect changes in current to prevent rupture, The amount of spill was determined on the safe side in advance and replaced. Visual precautions must be taken on a regular basis, and long inspection intervals may not reliably prevent rupture.
Visual observation itself may be difficult depending on the usage state of the rubber sleeve.

The method of embedding a metal electrode is superior to visual inspection because it can be continuously detected, but the area in which abrasion can be detected depends on the size of the electrode. If the electrode is small, only a small area can be detected and only local wear can be detected. This is effective when the position of wear is locally determined, but is useless if wear occurs at a position other than the electrode. In this case, it is sufficient to increase the area of the electrode, but as the area of the metal electrode increases, the entire rubber sleeve becomes hard, and the flexibility of the rubber sleeve is sacrificed.

[0004]

SUMMARY OF THE INVENTION The present invention aims to provide a rubber sleeve and a method for detecting its wear which can continuously monitor the risk of rupture without visually observing the flexibility of the rubber sleeve. Is what you do.

[0005]

According to the present invention, the above-mentioned objects are provided.
The present invention has solved the problem by developing a rubber sleeve with a structure in which a thin sheet of conductive rubber is contained inside the rubber of the rubber sleeve and a current can flow through the conductive rubber portion through an electrode connected to the conductive rubber. That is, a thin conductive rubber sheet is entirely or partially lined inside the rubber of the rubber sleeve, and a plurality of metal or conductive rubber electrodes are brought into contact with a part of the conductive rubber sheet, and a lead wire is formed from the electrode. Pull out the rubber and connect to the power supply.

When the rubber on the inner surface side is worn by the fluid flowing on the inner surface of the rubber sleeve and the conductive rubber is exposed on the surface,
Current leakage occurs due to contact between the conductive rubber and the fluid, and by detecting the leakage, wear of the inner rubber is detected. In the method of detecting wear of the rubber sleeve, a voltage is applied to the entire surface of the conductive rubber sheet, and the amount of current flowing when the inner rubber is worn and the conductive rubber is exposed and comes into contact with a fluid is detected.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A rubber sleeve is composed of an inner surface, an inner surface rubber, a conductive sheet, a reinforcing layer, and an outer surface rubber.
In some cases, if the pressure resistance is sufficient, a conductive rubber sheet may be lined between the reinforcing layers. The reinforcing layer is made of reinforcing cord, cloth, wire, etc.
Since the reinforcement layer covers most of the pressure resistance of the rubber sleeve, the conductive rubber is lined at a position where the conductive rubber is exposed before the reinforcement layer is worn. In the case of a rubber sleeve having no reinforcing layer at a low pressure, a conductive rubber sheet is lined at a position where a rubber thickness that withstands pressure resistance is guaranteed. The rubber sleeve has a cylindrical shape with a circular or elliptical cross section. The sleeve of the hopper discharge section may be a funnel-shaped or the like. The configuration of the current detection includes a conductive rubber, an electrode, a lead wire, a current detector, an alarm, and the like.

[0008]

1 and 2 show a first embodiment of the present invention. A rubber sleeve 1 used as a granulated slag discharge valve is a kind of a pinch valve and has a shape. As shown in Fig. 1, it has a funnel shape and consists of a large-diameter part (inlet side) 1a, a cone part 1b, and a small-diameter part (discharge side) 1c. When storing slag, shut off the small-diameter part with the pinch rod 2 and pinch it when discharging. The rod 2 is released. 1-2 during storage
Since a pressure of kg / cm ² is applied to the sleeve, a pressure-resistant design is made with a reinforcing cord. The inner rubber is worn by the granulated slag at the time of discharge, but the wear of the cone is the largest and the wear of the cone governs the life of the rubber sleeve. Lining and attaching two or more small electrodes 3 to a conductive rubber sheet having the composition shown in Table 1, connecting the electrodes to the lead wires 4,
Connect to the power supply outside the sleeve. The position of the conductive rubber sheet and the mounting of the electrodes are shown in FIG. As shown in Table 2, the conductive rubber sheet is adjusted to have a hardness of about 70 Hs and a surface resistance of about 200 Ω, and a voltage of 24 V is applied through a lead wire during use of the sleeve. When the inner rubber 7 is worn and even a part of the conductive rubber is exposed, the leakage occurs due to the granulated slag. You can know. When there is a reinforcing layer 9 such as a fiber knit in the funnel-shaped rubber sleeve 1, the sheet of the conductive rubber 6 is embedded in the inner rubber 7. It may be provided.

[0009]

[Table 1]

[0010]

[Table 2] Physical properties Hardness 70Hs Tensile strength 300KG / cm ² Elongation 500% Surface resistance 200Ω

Embodiment 2 FIG. 3 shows an example in which a pipe A and a pipe B perpendicular to the pipe A are connected by a rubber sleeve 10 according to a second embodiment of the present invention. In this example, the rubber sleeve has an elbow shape, and the inner wall of the portion bent at a right angle is most likely to be worn. Therefore, similarly to the above-described embodiment, when the inner rubber 7 is worn and even a part of the conductive rubber is exposed, it is detected that a leakage occurs due to contact with the internal fluid.

This is a round L-shaped tube (90 ° bend tube) rubber sleeve used as a silica sand slurry transport piping joint, having an inner diameter of 70φ total thickness of 10 mm, an inner rubber thickness of 5 mm from the inner side of the sleeve, and a conductive rubber. With 1 mm, 1 ply of reinforcement cord, and 4 mm of outer rubber, 6 layers of conductive rubber are lined over the entire circumference, and two metal electrodes in contact with the conductive rubber are attached to the end of the L-shaped tube. (Operating current 3m
A and below, the voltage between electrodes is 24V) and it is connected to the alarm and monitored.
About six months after the actual operation, the 90-degree corner of the rubber sleeve was worn, exposing the conductive rubber, and an alarm could be issued before the reinforcing cord was worn.

[0013]

Conventionally, in the case of a discharge valve of a granulated slag hopper, a visual inspection is periodically performed, an upper limit of a safe discharge amount is determined, and when the upper limit value is reached, replacement is performed regardless of the life of the rubber sleeve. However, the present invention can eliminate visual inspection,
Since the rubber sleeve can be used for its entire life, the amount of emission per sleeve is increased from approximately 60,000 tons to approximately 100,000 tons, enabling significant cost savings.

[Brief description of the drawings]

FIG. 1 is a side view of an example in which a rubber sleeve of the present invention is used for a discharge valve of a granulated slag hopper.

FIG. 2 is a sectional view of a main part of the rubber sleeve.

FIG. 3 is a cross-sectional view when orthogonal pipes are connected by a rubber sleeve of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rubber sleeve (funnel shape) 2 Pinch rod 3 Electrode 4 Lead wire 5 Electric leakage detector 6 Conductive rubber 7 Inner rubber 8 Alarm 9 Reinforcement layer 10 Rubber sleeve (elbow shape)

Claims (2)

(57) [Claims] 1. A rubber sleeve in which a thin sheet-shaped conductive rubber layer is provided inside rubber of a rubber sleeve, and an electric current can be applied to the conductive rubber portion through an electrode connected to the conductive rubber. 2. A fluid flowing on the inner surface of the rubber sleeve,
When the rubber on the inner surface wears and the conductive rubber is exposed on the surface, current leakage occurs due to contact between the conductive rubber and the fluid,
A method for detecting wear of a rubber sleeve, which detects wear of the inner surface rubber by detecting the leakage.