JPS62271327A - Leak detection of exhaust head - Google Patents

Abstract

PURPOSE:To be able to detect even a minute leak for reducing generation of inferior goods caused by the leak by setting the least upper bound value and the greatest lower bound value of output value to be detected by a vacuum pressure detector provided on an exhaust machine fitted with a tubular sphere. CONSTITUTION:The levels such as the least upper bound value A and the greatest lower bound value C of a set point are set up in anticipation of a usual fluctuation by measuring in a series of three rounds every exhaust head 4 with a vacuum pressure detector 9 fitted with a Pirani-vacuum gauge and when the values within the limits between the least upper bound value A and the greatest lower bound value C reach a plural number of pieces (for example, ten pieces), their average value B is found utilizing the fact that the fluctuation of a zero point or the like of the vacuum pressure detector 9 is relatively gentle. Said average value B is recognized as the average reference output value while an output value detected exceeding the preset anomaly decision output value E above said average reference output value B is recognized as an unusual exhaust head 4 and when an equally-numbered exhaust head 4 exceeds the anomaly decision output value E in a sieries of every round, the exhaust head 4 of said number is treated as unusual so as to be able to detect a leak of the exhausthead 4 with high probability.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a leak detection method of an exhaust head of an exhaust machine for a fluorescent lamp.

[Conventional technology]

The fluorescent lamp is held in communication with a plurality of exhaust heads provided in the exhaust machine through the exhaust pipe of the sealed bulb, and the inside of the bulb is evacuated and the filament of the electrode of the bulb is energized. It is made by activating the cathode material and then filling it with a small amount of mercury and a rare gas such as argon.

This exhaust machine is equipped with a vacuum pressure detector that detects airtightness defects such as cracks in the tube. An example of such a device is Public Utility Model Publication No. 58-91840, which is for tubes! The circuit configuration diagram of the airtightness defect detection device of the J1 aircraft is shown in Figure i4. In the figure, the tube 5 has an exhaust pipe 7 held by a plurality of exhaust heads 4, respectively.
It is connected to the manifold 6 through a rubber tube 10, a rotary valve 2, and a fixed valve 1. Then, the tube 5 is evacuated by the vacuum pump 3. A vacuum pressure detector 9 equipped with a Pirani vacuum gauge is installed between the fixed valve 1 and the manifold 6.

If there is a large airtight failure, the air cylinder 12 is moved via the electrode valve 13 and the rubber tube 10 is closed with the pincher 11, thereby shutting off the exhaust system. In addition, 21, 23 and 25 are switches, 22 is a solenoid valve,
24 is an electromagnetic relay.

In addition to cracks in the tube, poor airtightness in tube exhaust machines can also occur due to leaks in the exhaust head itself. The detected value of leakage from this exhaust head is often extremely small compared to the detected value of leakage from a tube rack or the like. In fluorescent lamps, even a minute leak causes impure gas to enter the bulb, preventing discharge and causing problems such as an increase in starting voltage.

To detect airtightness in exhaust machines, thermocouple vacuum gauges or Pirani vacuum gauges that utilize heat conduction are generally used as vacuum pressure detectors because they can perform continuous measurements. These vacuum pressure detectors are described in Chapter 4 of Vacuum Technology Course 3 Vacuum Measurement published by Nikkan Kogyo Shimbun, Inc. Vacuum Gauges Using Thermoelectric Power (49)
As described in page 12, there are disadvantages in that the sensitivity, zero point, etc. change greatly, and because it is a thermal measurement, it is easily affected by the influence Δ of the outside world. Furthermore, the output of an amplifier that amplifies the output of a vacuum pressure detector also fluctuates somewhat depending on the ambient temperature and the like.

Therefore, in order to improve the accuracy of detecting poor airtightness of the tube, there is a method as shown in the above-mentioned Utility Model Publication No. 58-91840.This detection method can detect minute leaks such as leaks from the 1st air head. It is not a highly accurate detection method.

[The problem that the invention attempts to solve]

As mentioned above, the vacuum pressure detector in the conventional exhaust machine does not have a highly accurate detector for detecting minute leaks such as in the exhaust head, and there is no way to reliably detect abnormalities in the exhaust head.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a leak detection method for an exhaust head that can detect even minute leaks and reduces the occurrence of defective products caused by leaks. It is.

[Means for solving problems]

The upper and lower limits of the output value detected by the vacuum pressure detector installed in the exhaust machine equipped with the tube are set, and multiple units detected within the range of the upper and lower limits of the output value are set. The output values are averaged and set as the average and semi-output values, and an abnormality judgment output value is set, and the output value exceeding the above abnormality judgment output value than the above average standard output value is repeatedly and continuously from the same exhaust head. This is a detection method that detects a leak in the exhaust head.

(Example) Hereinafter, a method for detecting a leak in an exhaust head according to the present invention will be explained with reference to the drawings.

FIG. 3 shows an embodiment of a device for detecting airtightness caused by an exhaust machine according to the present invention. In the figure, 1 to 1
3 is the same as the conventional device described above. The signal from the vacuum pressure detector 9 is converted into a digital signal by an ND converter 16 via an amplifier 15 and then input to a computer 17 . This computer 17 receives signals from a sensor (not shown) for detecting basic heads for recognizing the numbers of the plurality of exhaust heads 4 and a sensor (not shown) for detecting indexing of the rotary valve 2. It is used to check the timing of data acquisition and the number of the non-air head 4. The computer 17 is equipped with an external storage device 18 such as a generally used magnetic disk, and various reference values set in advance are input manually from a terminal device 19. The computer 17 performs calculations according to a predetermined program, and if it detects a large airtight failure, it immediately sends a signal (No. 2) to the control device 14 to operate the air cylinder 12 via the solenoid valve 13 and close the rubber pipe 10 using the pincher 11. By closing, the exhaust air is blocked.

Figures '5tS1-1 to 1-3 show that the vacuum pressure detector 9 equipped with a Pirani vacuum gauge is used to detect the
This is a graph of values that have been constant for 1 jll in consecutive cycles. In the figure, the vertical axis is the output value P detected by the vacuum pressure detector 9, and the horizontal axis is the head number (N
o,) was shown. Figure 1-1 is 'f, 1 round [1, 1st-
Figure 2 is a detection graph for the second round, and Figures 1-3 are detection graphs for the third round [1]. In the figure, the lower the output value P, the higher the degree of vacuum.

1-1 (Exhaust head number or No. as shown in /il)
, 7 indicates a large output value F, indicating a large leak, and exhaust head number No. 13 indicates a relatively low output value G, indicating a small leak. Also, tube 5
When the exhaust head 4 is not attached to the exhaust head 4 with the fastening rubber 8, or when it is a rough airtight detection device and the rubber pipe IO is closed by the pincher 11, the exhaust head number shown in Fig. 1-2 is As with the output value of N008, the load on the vacuum pump 3 is small and the degree of vacuum is improved. The occurrence of poor airtightness due to leakage of the tube 5 occurs sporadically in the exhaust head 4 with the same number as shown in the output value F shown in Figure 1-1, and in the exhaust head 4 with the same number, it occurs continuously at 2. The probability of it occurring twice or three times decreases. That is, since failures due to leakage of the tube 5 occur randomly, it is extremely rare for them to occur continuously. However, the tightening rubber 8 of the exhaust head 4
If a defect occurs due to a leak, there is a high probability that it will occur repeatedly every cycle. In a line where fluorescent lamps flow continuously at high speed, the upper limit value A for detected abnormal output values is set in anticipation of fluctuations in the vacuum pressure detector 9 and the amplifier 15, so it is relatively easy to use. Leakage from a small exhaust head or the like with a small output value G cannot be detected.

Therefore, in the present invention, levels such as the upper limit value A and lower limit value C of the measured value are set in anticipation of normal fluctuations, and the fluctuation of the zero point of the vacuum pressure detector 9 is relatively gentle. , there are multiple values within the range of upper limit value A and lower limit value C (
For example, when the number of pieces reaches 10, the average value B is calculated. This average value B is defined as an average standard output value, and an output value detected exceeding a preset abnormality judgment output value E than this average standard output value B is recognized as an abnormal exhaust head 4, and an exhaust head with the same number is recognized as an abnormal exhaust head 4. 4 continuously exceeds the abnormality determination output value E every lap, the exhaust head 4 with that number is treated as abnormal, thereby making it possible to detect a leak in the exhaust head 4 with a high probability.

FIG. 2 is an example of a flowchart processed by the computer 17. In the initial value settings, the output values of the upper limit value A, lower limit value C1, average reference value B, and abnormality judgment value E are obtained from the external storage device 18, but when these values are changed, this flowchart is obtained by another program. program. When the measurement start signal is received, the data is input and the head number is recognized. This head number is recognized only when the reference head is detected, and the number of the exhaust head inputting data is obtained by incrementing it by 1 each time the index is performed.

The data is compared with an upper limit value A and a lower limit value C of the output value, and if it exceeds the upper limit value A of the output value, it is unconditionally determined that the airtightness is poor. Further, as shown in FIG. 1-2, if the data K is smaller than the lower limit C of the output value (as in the output value), it is determined that the tube 5 is not attached to the iJc. A≧
If ≧C, it is treated as data for calculating the average reference output value B, and when such data is used, for example, 10 times, the average reference output value B is calculated and becomes the new reference output value. The measured data is stored in a table on the memory for each head number, and the average standard output value B is subtracted from the data, and if it is larger than the preset abnormality judgment output value E, it is determined to be abnormal and stored in the table for each head number. is memorized.

Next, it is checked whether an abnormality has occurred in the data up to the previous time for the exhaust head with the same number.

In the example of the flowchart of FIG. 2, if an abnormality occurs three times in a row, it is determined that there is an abnormality in the exhaust rad 4 of that number, and an alarm is issued.

(Effects of the Invention) The exhaust head leak detection method according to the present invention has the following effects.

(b) Set the upper and lower limits of the output value in anticipation of fluctuations in the R device itself, such as a vacuum pressure detector, and also set the upper and lower limits of the output value by taking advantage of the gradual fluctuation of the zero point of the vacuum pressure detector. When multiple output values are detected within a period of time, the average value is calculated and used as the average reference output value, and an abnormality judgment output value is set. (b) Since even minute leaks in the exhaust head can be reliably detected, the occurrence of tubes with poor airtightness can be prevented to a minimum.

(8) Since exhaust machine data is processed by a computer, it is possible to easily check the output value detected for each exhaust head number and take appropriate measures.

[Brief explanation of drawings]

1-1 to 1-3 are graphs showing an embodiment of the exhaust head leak detection method according to the present invention, FIG. 2 is a flowchart showing an embodiment of the exhaust head leak detection method, and FIG. FIG. 4 is a circuit configuration diagram of an airtight tube detection device for an exhaust machine to which the exhaust head leak detection method according to the present invention is applied, and FIG. 4 is a circuit configuration diagram of a conventional exhaust machine airtightness tube detection device. 1...Fixed valve 2...Rotating pulp 3...Vacuum pump 4...Exhaust head 5 ......Tube 6...Manifold 7...Exhaust pipe 9...Vacuum pressure detector 14... ... Control device 16 ... A/D converter 17 ... Computer 18 ... External storage device 19 ... Terminal device

Claims (1)

[Claims] The upper and lower limits of the output value detected by the vacuum pressure detector installed in the exhaust machine equipped with the tube are set, and multiple units detected within the range of the upper and lower limits of the output value are set. The output values of are averaged and set as the average reference output value, and an abnormality judgment output value is set.
A method for detecting a leak in an exhaust head, characterized in that when an output value exceeding the abnormality determination output value is repeatedly and continuously detected from the same exhaust head, it is determined that the exhaust head is leaking.