JPS6239750A - Method for detecting abnormal of nozzle of high pressure water jet cutter using abrasive material - Google Patents

Abstract

PURPOSE:To make it possible to detect abnormality by monitoring the state of a nozzle, by providing an electrode to the end part of a nozzle and supplying a current to said nozzle. CONSTITUTION:A nozzle 19 comprises a material having relatively good conductivity and a pair of electrodes 30, 31 each having a predetermined resistance value are mounted in the vicinity of the leading and base ends of the nozzle 19. High pressure water comes to high pressure water jet having an abrasive material mixed therein and, hen said high pressure water jet flows out from the leading end of the nozzle 19, a current is supplied to a nozzle abnormality detection circuit to monitor the state of the nozzle 19. This nozzle 19 receives abrasion on the inner wall of the jet passage 26 thereof with the elapse of time and the diameter of the passage 26 is gradually enlarged. When this change is normal, the current value detected by an ammeter 33 gradually changes according to a definite rule. When offset abrasion is generated in the passage 26 and partial abrasion markedly advances in the nozzle 19, the current value detected by the ammeter 33 changes irregularly and violently and the nozzle 19 is destructed at an area where abrasion excessively advanced. Therefore, offset abrasion is detected by catching the irregular change of the current value.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention provides a method for detecting nozzle abnormality in a high-pressure water jet cutting machine using an abrasive material, in particular detecting the state of wear of the nozzle, and detecting nozzle damage at an early stage. The present invention relates to a nozzle abnormality detection method that can be used to detect and prevent major accidents.

<Prior Art> There is a method of using a high-pressure water jet for processing metals and other materials, but in order to improve the cutting and polishing efficiency of the workpiece, there is a method of mixing an abrasive in the nozzle part. The nozzle of a high-pressure water jet cutting machine that uses such an abrasive material has conventionally had a structure as shown in FIG. .

A high-pressure water jet mixed with an abrasive material passes through the water passage hole la.

<Problems to be Solved by the Invention> However, in the conventional nozzle 1 as described above, when high-pressure water and abrasive material pass through the water passage hole 1a, severe wear occurs inside the nozzle 1. .

In this case, if the nozzle 1 itself is normal, the inner diameter of the water passage hole 1a will gradually expand approximately evenly.

Replace the nozzle after a certain lifespan. However, when uneven wear occurs in the water passage hole 1a of the nozzle 1, the inner diameter does not expand uniformly, but expands partially, resulting in partial destruction as shown in FIG. Then, high-pressure water mixed with abrasive material flows out from this broken part 2,
The flow rate from the tip of the nozzle 1 is reduced, and the cutting ability is significantly reduced.

Such a situation occurs suddenly, and it is difficult to predict the destruction of the S nozzle. Furthermore, it has been impossible for humans to constantly monitor the nozzle due to the presence of flying objects and the risk of the nozzle being destroyed.

The present invention has been made in view of these conventional problems, and its purpose is to monitor the condition of the nozzle, understand the state of wear, determine when it is time to replace the nozzle, and detect the very early stages of breakage or the like. The object of the present invention is to solve the above-mentioned conventional problems by providing a method that can detect an abnormality immediately before it occurs.

<Structure of the Invention> In order to achieve the above object, the present invention attaches a pair of electrodes to the nozzle of a high-pressure water jet cutting machine that uses an abrasive material, configures an electric circuit with the nozzle itself as a component, and injects a current into this circuit. The gist of the system is to conduct electricity and monitor changes in the current.

Effect> If a high-pressure water jet containing an abrasive is injected while conducting current to the circuit for detecting nozzle abnormality, if the water passage hole of the nozzle is uniformly worn, the current flowing through the circuit will decrease. changes with certain regularity. However, when uneven wear occurs and a portion of the wall surface of the water hole rapidly wears down, the circuit current also changes irregularly. In addition, the change becomes sudden during destruction.

Abnormality detection is performed by capturing such changes. This abnormality detection may be performed by measuring the current flowing through the circuit or by measuring the voltage between the electrodes. -<Example> FIG. 1 is a sectional view showing a nozzle part of a high-pressure water jet cutting machine using an abrasive material to which the nozzle abnormality detection method of the present invention is applied. This nozzle part is a high-pressure water generator (not shown)
It consists of a nozzle base 11 that is coupled to a nozzle base 11 and receives high-pressure water supplied from the nozzle base 11, a nozzle holder 14 attached to the tip of the nozzle base 11, and a nozzle 19 held by the nozzle holder 14. .

The nozzle base 11 has a threaded fastening hole 20 that connects to a hose or piping, and a high-pressure water path 21 that extends in communication with the fastening hole 20. A filter 12 is arranged in the high-pressure water path 21. It is set up. The nozzle base 11 and the nozzle holder 14 are fastened together by a mounting thread 22, and an orifice mount 13 for generating a high-pressure jet water stream is disposed at the joint between the two members. A water road 23 communicating with the high-pressure water road 21 via the orifice mount 13 is formed in the nozzle holder 14, while an abrasive supply path 24 is formed which branches off and joins the water road 23.

The nozzle holder 14 and the nozzle 19 are connected to each other by a nozzle adapter 16 fastened to the nozzle holder 14 by a mounting thread 25 .

That is, the base end of the nozzle 19 is inserted into the nozzle adapter 16, the valve member is firmly connected by the screw 17 of the compression nut 18, and the nozzle adapter 16 is further screwed to the nozzle holder 14 to attach the nozzle 19.

A tapered sleeve 15 is interposed between the base end of the nozzle 19 thus attached and the distal end of the nozzle holder 14.

The nozzle 19 has a longitudinally extending jet passage 26 in its center. The tapered sleeve 15 has a tapered hole 27 having a large diameter almost the same as the waterway 23 on the base end side and a small diameter almost the same as the jet passage 26 on the distal end side, which gradually widens from the tip to the rear end. are doing. Further, the nozzle 19 is made of a relatively conductive material, and a pair of electrodes 30, 31 having a predetermined resistance value are attached to the nozzle 19 near its tip and base ends.

A schematic configuration of this nozzle 19 is shown in FIG. Nozzle 1
A power source 32 and an ammeter 33 are connected to the electrodes 30, 31 attached to the nozzle 9, forming an abnormality detection circuit that detects wear and breakage of the nozzle, which includes the nozzle 19 itself as a component.

With this configuration, when high-pressure water is supplied from the high-pressure water generator and this high-pressure water becomes a high-pressure water jet mixed with an abrasive material and flows out from the tip of the nozzle 19, current is conducted to the nozzle abnormality detection circuit and the nozzle is activated. monitor the status of

The inner wall of the jet passage 26 of the nozzle 19 is worn over time, and the diameter of the jet passage 26 gradually increases. When this enlarged change is normal, the current value detected by the ammeter 33 gradually changes according to a certain rule. However, uneven wear occurs in the jet passage 26 and the nozzle 19
When wear progresses significantly in a part, the ammeter 33
The current value detected by the current value changes irregularly and drastically. Then, the nozzle 19 breaks at a portion where wear has progressed to an extreme degree. Therefore, uneven wear is detected by detecting irregular changes in the current value, and the main body of the high-pressure water generator is stopped or the nozzle is replaced.

In the above embodiment, the abnormality of the nozzle 19 is detected by measuring the current value, but as shown by the dotted line in Figure 2, a voltmeter 34 is placed between the electrodes 30 and 31, and the abnormality is detected by measuring the voltage. Of course it's fine. Further, in the above embodiment, the case where the nozzle 19 itself is made of a good electrical conductor is explained, but unlike this, the nozzle 1
If 9 is a non-good conductor, a metal film that is an electrically good conductor is attached to the entire side surface of the nozzle 19, and electrodes 30 and 31 are attached on top of this to form a nozzle abnormality detection circuit. It may also be possible to detect abnormalities in

<Effects of the Invention> As explained above, according to the present invention, abnormalities in the nozzle are detected by providing an electrode at the end of the nozzle and conducting current through the nozzle, so that abnormalities in the nozzle can be detected before the nozzle breaks down. It is possible to remotely detect abnormalities in the nozzle at an early stage when the nozzle is damaged or broken, thereby improving the efficiency of cutting work using a high-pressure water jet cutting machine and making it possible to perform the work safely.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the nozzle structure of a high-pressure water jet cutting machine using a nozzle to which the present invention is applied. FIG. 2 is a diagram schematically showing the configuration of a nozzle abnormality detection circuit, and FIG. 3 is a perspective view schematically showing the structure of a conventional nozzle.
FIG. 4 is a perspective view showing a state in which the nozzle shown in FIG. 3 is partially destroyed. 1.19... Nozzle, 11... Nozzle base, 14... Nozzle holder, 26... Jet passage, 30. 31... Electrode, 32... Power supply, 33... Ammeter, 34... Voltmeter.

Claims (1)

[Claims] The nozzle of a high-pressure water jet cutting machine that uses abrasive material is made of a conductive material, and electrodes are attached to both ends of the nozzle. Electric current is passed through the nozzle and changes in this current are monitored to prevent wear and tear on the nozzle. A method for detecting abnormality in a nozzle of a high-pressure water jet cutting machine using an abrasive material, characterized by detecting.