JPS593237A - Percussion detector for inspecting internal pressure of can or the like - Google Patents

Abstract

PURPOSE:To obtain a stable detection value by passing a can through a demagnetizer prior to inspection with an expanded can detector. CONSTITUTION:A demagnetizer 9 is arranged before a probe an expanded can probe 7. As passing through a base frame 11 of the demagnetizer 9, a case (x) to be inspected is demagnetized receiving an alternate magnetic field with a coil 12 fixed on a bakelite plate 13. The demagnetization brings the detection value with an expanded can detector to the normal level to reduce the standard deviation thereby assuring a stable detection value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inspection device for inspecting the internal pressure of sealed containers such as bottled and canned containers, particularly for inspecting cans housed in carton cases from the outside.

In the case of general foods such as bottled and canned foods, they are filled under a specified vacuum condition to prevent oxidation and spoilage of the filled food, but the degree of vacuum inside the bottle or can decreases due to causes such as poor sealing due to spoilage of the contents. There are things to do. In the case of carbonated beverages, etc., the contents are filled under pressure, but leakage caused by poor seaming may cause a drop in pressure.

These pressure fluctuations appear after some time has passed after filling the bottles, cans, etc., so after filling the bottles, put them in the carton case, and - weeks @ 50 o'clock till have elapsed.
Communication is what is inspected before shipping. Therefore, it is required to detect internal pressure defects without unpacking the cart/case.

Recently, type 1 can detectors and automatic sound percussion detectors have been used as this type of internal pressure testing equipment.

Expansion can detectors detect changes in the magnetic field due to changes in the distance between the sensor and the can lid as changes in inductance (-2); This device detects defective cans by vibrating the can lid using lines of magnetic force and sensing the sound generated.

(For example, Japanese Unexamined Patent Publication No. 53-119087) By the way, in the filling process of canned goods, etc., it is often necessary to inspect the internal pressure of each can after seaming. A test instrument has been installed. '1f
rWi is generally made of soft iron and is easily magnetized. Therefore, when the can lid passes through an automatic sound tester, lines of magnetic force act in a certain direction, and the can lid becomes magnetized. When a magnetized can lid is measured with an expansion can detector, the detected value will change depending on the state of magnetization. In particular, when scanning a can lid and taking its profile, if the entire lid is magnetized uniformly, the detected value will not be affected, but the position of the can lid and the part of the automatic sound detector that generates magnetic field lines Generally, the state of magnetization differs in each part of the can lid depending on the relationship.

As a result, the detected value will be affected. FIG. 1 shows the relationship between the can internal pressure and the detected value, and is an example of the influence of magnetization by the automatic sound detector on the detected value (MD value) of the expansion can detector.

From this graph, the cans magnetized by the automatic sound tester are compared with those before being magnetized. This shows that the MD value is 3-7 higher than the actual can internal pressure, which is equivalent to 0.1-0°3''ii lower than the actual can internal pressure. If the MD exclusion setting value is set to 5 for the purpose of eliminating
If it is not Jl-, it will not be excluded, n-n, 25m
The filth is purified by 17 degrees and 1 degree. As a measure for this, use the exclusion setting value as an example 'F! -f' can be changed to 10, but as mentioned in L, the shift value of and changes depending on the positional relationship between the can lid and the magnetic force generation part of the automatic sound tester, so it is not possible to set a constant optimal shift value. 5. The present invention solves the above problems by rounding and dilating? 9
Before inspection with a detector, pass through a degaussing device for 12 minutes to stabilize it. DaM
D It was better to get @.

The case percussion detector shown in Fig. 2, which will be explained in detail with reference to the drawings below, is composed of an expansion can detector and an automatic sound percussion detector, including a one-note percussion probe and a two-note percussion indicator. Control department, 3
7 is a scanner, 7 is an expansion can detection unit, 8 is an expansion can detection instruction control unit, 9 is a degaussing device, 4 is a measurement conveyor, 6
5 is the control panel, and 5 is the sorting conveyor.

This percussion tester is generally used in such a way that if a carton case is rejected as containing defective cans during the first or second inspection, it is passed through the percussion tester again to reconfirm the quality of the case. Ru. In the first case, the MD value for the first and second use will be different even for the same can), making it even more difficult to select the reject setting value.

In the present invention, a degaussing device 9 is provided before the expansion can detection probe.
It is characterized by the placement of As shown in Figure f$3, the degaussing device is composed of a magnetic field generating section and a cooling section. As is well known, demagnetization is done by applying a damped alternating magnetic field. It is done. The case 10 to be inspected is the underframe 11 of the degaussing device 9
When passing through the inside, it moves through an alternating magnetic field caused by an alternating current flowing into a magnetic field generating section consisting of a coil 12 mounted on a Bakelite plate 13, and is effectively subjected to an attenuating alternating magnetic field, so that it is demagnetized by cracks. Ru. Since supplying AC current to the coil is accompanied by multiple heat generation, it is necessary to cool the cooling unit 14 (therefore, cooling is required), which is composed of a heat sink and a fan. 15 is a cover.

If you are working on a coffee drink and there is no degaussing (
Here is an example of a comparison of MD values between (without) and (with).

Table 1. Effect of demagnetization on MD value (after passing through the line inspection machine) N = 30 cans It can be seen that if p1 demagnetization is performed, the measured value will not only be lower than the original value but also the standard deviation will be small, improving detection accuracy. As a result, it is possible to minimize the error of overlooking a can with poor internal pressure or eliminating it from can production.

In the above example, the case was explained as a percussion tester for reconfirming rejected cases, but the magnetization of can lids is not only caused by the automatic percussion tester; It also occurs during the can manufacturing process, etc., so it can be used before any expansion can detector, such as inspecting the internal pressure of not only cans packed in cartons but also individual cans, and has a significant effect on improving the accuracy of determining good or bad. It is.

[Brief explanation of the drawing]

@ 1 +q is the can internal pressure and vf l) (Graph showing the relationship with IT, Figure 2 is a front view of the percussion inspection machine of the present invention, Figure 3 is a front view and plan view of the degaussing device 1: Sound percussion Test probe 2:
Sound inspection instruction control section 3: Scanner 4: Measurement conveyor 5: Sorting conveyor 6: Operation panel 7: Expansion can detection probe 8: Expansion can detection instruction control section Q: Demagnetization device fF! t, 1
1: Underframe 12: Demagnetizing filter 14: Heat dissipation part Patent application Toyo Seikan Co., Ltd. Applicant's agent Patent attorney Aya Sato (and 1 other person) 71

Claims (1)

[Claims] In a device that measures the distance between a magnetic gold layer lid and a sensor as a change in inductance to test the internal pressure of sealed containers such as cans, a degaussing device is placed in front of the expansion detection probe that detects the lid profile. A striking device for inspecting the internal pressure of cans, etc.