JPH0576885B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention accurately detects the occurrence of abnormal galling wear due to metal contact between the screw and cylinder of a screw-type kneading/conveying device composed of a screw and a cylinder. It is about the method.

(Prior Art) An example of this type of screw-type kneading/conveying device is one designated by the reference numeral 100 in FIG. In this screw type kneading/conveying device 100, the hopper 1
When the raw material 5 is supplied to the cylinder 2, the raw material 5 is kneaded by the screw 3 and discharged from the die 4. Normally, in such a screw-type kneading/conveying device, the screw 3 is supported by a cantilever bearing of only the screw base 3a, which improves the kneading performance of the raw materials and stabilizes the state of discharge from the die. Therefore, the diameter of the screw valley is increased near the tip of the screw.

As a result, if the operating conditions of the device do not match the screw specifications, a pressure imbalance will occur within the cylinder 2, and the screw 3 will come into direct strong metal contact with the cylinder 2, causing galling wear. be. Conventionally, the method used to detect the occurrence of galling wear is to record and observe the internal pressure state using a pressure sensor inserted into the cylinder from outside the cylinder 2, but this detection method Since the pressure state changes depending on the raw material and the operating conditions of the equipment, it has been difficult to accurately detect and determine whether galling wear has occurred. In addition, this detection method had a problem in that the raw material remained in the insertion hole for inserting the pressure sensor, and it was not satisfactory as a method for detecting galling wear.

(Problems to be Solved by the Invention) In other words, the conventional method for detecting galling wear between the screw and the cylinder attempts to detect it based on pressure changes inside the cylinder, which is susceptible to other factors and cannot accurately detect galling wear. In many cases, it is difficult to judge whether the pressure sensor is in the cylinder or not, and there is also the problem that the raw material accumulates in the insertion hole for inserting the pressure sensor into the cylinder.

The present invention was developed in view of these conventional drawbacks, and aims to provide a method for accurately detecting occurrence of galling wear due to metal contact between the screw and the cylinder without performing any processing on the cylinder itself. It is.

(Means and effects for solving the problem) For this reason, the present invention provides a screw-type kneading and conveying device in which a screw rotates within a cylinder, in which an acoustic emission (AE) sensor is installed on the outer wall of the cylinder. The apparatus is configured to detect abnormal noise occurring within the cylinder, and to process this detection signal to determine that it is galling wear occurring between the screw and the cylinder,
This is a means to solve the above problem.

That is, an AE sensor is attached to the outer wall of the cylinder to detect the sound called acoustic emission (AE) that occurs when solid materials undergo plastic deformation or breakage, and the sound generated inside the cylinder is detected.
For example, the same detection signal is processed by selecting a signal wave outside a predetermined band using a waveform processor, and then converted into a pulse wave and compared with a set value as a function of time.
If it is larger than the set value, it is determined that galling wear has occurred.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. Screw type kneading/conveying device 100
An AE sensor 6 is attached to the outer wall of the cylinder 2. In the figure, 200 indicates an AE processing device.

Now, if the screw 3 and the cylinder 2 come into contact for some reason and cause galling wear, AE occurs and is detected by the AE sensor 6. The output of the AE sensor 6 is transmitted via a signal line 7 to an amplifier 8 to each signal processor described below.

Here, the amplifier 8 amplifies the output signal of the AE sensor 6 to a processable level. FIG. 2a shows the output state at this time. The bandpass filter section of the waveform processor 9 selects a processing frequency band, the signal is detected by the detection section, and the signal having a level higher than the level set by the level setter 10 is selected and sent to the next gate shaper 11. As shown in FIG. 2b, the gate shaper 11 shapes a signal having a set level or higher into a gate pulse corresponding to its duration.

The pulse oscillator 12 is an oscillator that has a pulse having a sufficiently short cycle compared to the gate time, and in response to the gate signal from the gate shaper 11, outputs a pulse corresponding to the gate time as shown in FIG. 2c.

The pulse counter 13 counts this pulse for the count gate time set by the count time setter 14.

The clock oscillator 15 is a count time setter 1
4 reference time oscillator.

The count number setter 17 sets a count number previously determined to be abnormal, and the count number comparator 16 compares this set count number with the pulses counted by the pulse counter 13. At this time, if the pulse count number is larger than the set count number, the count number comparator 16 sends a signal to the alarm transmitter 18, and the alarm transmitter 18 issues an alarm.

(Effects of the Invention) As described above in detail, the present invention provides the following effects.

(1) Since the contact status between the screw and the cylinder is directly detected from the outer wall of the cylinder, abnormality detection is more reliable than with conventional monitoring methods. It has no effect on the condition.

(2) Since the processing setting level and time for the generated AE signal can be changed arbitrarily, it is possible to detect an abnormality at an extremely minor stage of damage to the screw and cylinder.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an abnormality detection system that is an embodiment of the present invention, and FIG. 2 is a diagram of each signal waveform within the AE processing device. Explanation of the main parts of the diagram, 2...Cylinder, 6...
AE sensor, 100...screw type kneading/conveying device, 200...AE processing device.

Claims (1)

[Claims] 1 In a screw-type kneading/conveying device in which the screw rotates within the cylinder, an acoustic emitter (AE) attached to the outer wall of the cylinder
A screw-type kneading/conveying device characterized in that it uses a sensor to detect abnormal noise occurring within the cylinder, and by processing this detection signal, it is determined that it is galling wear occurring between the screw and the cylinder. Anomaly detection method.