JPH0357953A - Method for removing scale of rotary body of ultrasonic flaw detection apparatus - Google Patents

Abstract

PURPOSE:To wash and discharge scale within a short time by repeating the normal and reverse rotation of a flaw detection rotor for required time in the number of rotations within a range of 200 - 400 rpm at every flaw detection work for a definite time. CONSTITUTION:A flaw detection rotor 1 is rotated at a required speed by driving a motor and flaw detection water is injected into the rotor 1. A rubber packing 3 has function for forming a water film between the material to be inspected transferring through the rotor 1 and a flaw detection sensor 2 without forming a gap. The scale on the rotor 1 is removed by repeating the normal and reverse rotating of the flaw detection rotor 1 for a required time in the number of rotations within a range of 200 - 400 rpm for each flaw detection work for a definite time. That is, since the normal rotation and reverse rotation of the rotor 1 are repeated while flaw detection water is allowed to continuously flow, the impulsive turblent movement of water is generated in the rotor 1 and the scale adhered to the sensor 2 is effectively released by the notion and discharged along with stayed scale so as to flow over a rubber partition wall and washing is completed within an extremely short time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for removing scale from a rotating body for maintaining the accuracy of an apparatus for ultrasonic flaw detection of rolled steel bars, wire rods, etc.

(Prior Art) All rolled steel bars, wire rods, etc. are inspected for flaws using, for example, ultrasonic flaw detection to ensure quality. This flaw detection method uses a rotating body (hereinafter referred to as "
A device is used that rotates a flaw detection rotor at high speed and detects flaws in a spiral pattern. FIG. 3 shows a schematic structure of this type of flaw detection device, where l is a flaw detection rotor, 2 is a flaw detection sensor 3, and is a rubber packing. The flaw detection water is injected. Note that the rubber packing 3 is used to hold the material to be inspected that passes through the flaw detection rotor 1 and the sensor 2.
It serves to create a water film with no gaps between the two.

The material to be inspected is detected in a spiral pattern through water by a flaw detection sensor 2 that rotates at high speed, and the detected vertical and oblique signals are output as flaw signals by a vertical ultrasonic flaw detector and an oblique ultrasonic flaw detector, respectively. The signal is processed by a microcomputer and then output to a CRT and printer. Note that the microcomputer calculates the presence or absence of flaws, depth, length, width, etc.

(Problem to be solved by the invention) By the way, the steel bars, wire rods, etc. that are the materials to be inspected have been rolled and cooled, and many of them have scales such as black scale attached to their surfaces, which can peel off in the flaw detection rotor. However, it remains without being discharged and thickly covers the surface of the sensor, which not only reduces sensitivity but also causes flaw detection failure. Conventionally, flaw detection rotors have been cleaned and replaced on a regular basis, but this has forced the operation line to stop for long periods of time, resulting in a decline in operating rates. Note that this type of equipment is classified as a precision machine and has problems such as requiring advanced technology for disassembly and cleaning.

The present invention was made to solve this problem, and an object of the present invention is to provide a scale removal method that can clean and discharge scale in a short time without requiring disassembly and assembly of the device. do. (Means for Solving the Problems) In order to achieve the above object, a method for removing scale from a flaw detection rotor of an ultrasonic flaw detection device according to the present invention requires 200 to 400 rpm for each flaw detection operation for a certain period of time. p. The flaw detection rotor is repeatedly rotated forward and reverse at a rotational speed within the range of m for the required time.

In the present invention, the number of rotations of the flaw detection port which rotates forward and reverse is set at 200 to 400 r. p. m is 200r
．． p. This is because if it is less than 400 r.m, the water impact during reversal will be too small and the cleaning power will be too small. This is because if it exceeds p and m, one cycle of forward rotation and reverse rotation becomes longer and the cleaning effect decreases.

According to the inventors' experiments, 250 to 350 r. p. m
is most preferred.

(Function) In the present invention, since the flaw detection rotor is repeatedly rotated forward and reverse while the flaw detection water continues to flow, an impactful turbulence of water occurs within the flaw detection rotor, thereby effectively peeling off the scale attached to the sensor. The scale is then discharged over the rubber partition, and cleaning is completed in a very short time.

(Example) In the conventional flaw detection device described above, the motor power source is a so-called one-way thyristor converter that rotates only in the forward direction. Therefore, when implementing the present invention, for example, a magnetic contactor In addition to switching the power supply polarity,
For example, 320r.
p. A design change to the automatic forward/reverse operation control circuit is required to reduce the speed from m to speed O.

Figure 1 is an oscillograph during a cleaning operation showing an embodiment of the present invention.Since it is preferable to complete cleaning in a short time, for example, forward and reverse rotations are performed at intervals of 4 seconds within a 60 second cleaning time. It is set to repeat. By the way, the time point at which the cleaning operation is performed differs depending on the size of the material to be tested. For example, the relationship between the size of the material to be tested and the time point at which the cleaning operation is performed is shown in the table below.

The table, that is, the cleaning pattern may be defined based on the relationship between the number of flaw detection materials and the S/N ratio, as shown in FIG. Figure 2 shows 32O when the number shown in the table above is reached.
r. p. Figure 2 shows the change in S/N ratio when the rotation speed of m is rotated forward and reverse for 60 seconds at 4-second intervals, and the effect of the method of the present invention can be seen from this figure.

(Effects of the Invention) As explained above, the present invention provides a 200 to 400 R.P.I. P. It repeats forward and reverse rotation for the required time at a rotation speed within the range of A complete cleaning is completed in no time. Therefore, it can be expected to prevent a decrease in flaw detection sensitivity and improve flaw detection ability and productivity.

[Brief explanation of drawings]

FIG. 1 shows an example of an oscillograph during a cleaning operation according to the present invention, and FIG. 2 is a cleaning pattern diagram. Moreover, FIG. 3 is a schematic structural diagram of the flaw detection device. 1 is the flaw detection rotor, 2 is the flaw detection sensor Figure 1 Figure 2 = 9! ! Figure 3

Claims (1)

[Claims] (1) A method for removing scale deposited on the inner surface of a rotating body constituting an ultrasonic flaw detection device, which requires 200 to 400 r.p.m. for each flaw detection operation for a certain period of time. p. A method for removing scale from a rotating body of an ultrasonic flaw detection device, characterized by repeating forward and reverse rotation for a required period of time at a rotational speed within a range of m.