JPS59105535A - Detecting method for pinhole of packed article - Google Patents

Abstract

PURPOSE:To detect pinholes efficiently by a construction wherein air bubbles occurring from a packed article by the action of vacuum in a vacuum box are gathered in the top part of a bubble-gathering conical element and the air bubbles thus gathered in said top part are caught electrically by a sensor. CONSTITUTION:A number of sets of vacuum boxes 2 each containing water are conveyed by a conveyor 1 so that air bubbles occurring from pinholes of a packed article A are gathered in one place by a bubble-gathering conical element 16, and these air bubbles are caught and taken out as electric signals by a sensor 22. By supplying packed articles one by one into these vacuum boxes in a part in which the vacuum boxes are opened, the packed articles having the pinholes are detected automatically, and thus these packed articles with the pinholes can be sorted efficiently by a small number of operators.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for efficiently detecting the presence or absence of pinholes in a packaged product formed by sealing an article such as a food product with a packaging material such as a plastic film or aluminum foil.

Bags made of thin flexible materials are often used as a relatively low-cost packaging material for sealing items to be packaged, but pinholes often occur in these packaging materials due to poor welding at sealing points. do. Pinholes can cause the packaged items inside the packaging material to absorb moisture, but pinholes in packaging products filled with inert gas or oxygen absorbers can cause the items inside to absorb moisture for a short period of time. This constitutes a cause that is affected by oxygen (outside air). Particularly in the case of food, mold grows after shipping and the product is returned, and it is also unreliable in terms of hygiene.

Conventionally, the method of detecting pinholes from the air bubbles generated when packaged products are submerged in water has been extremely difficult, but compared to the number of packaged products that can be efficiently produced by automatic packaging machines. Therefore, a large number of inspectors were required to balance the number of packaged products produced.

In view of the above-mentioned points, the present invention circulates a large number of vacuum boxes each consisting of a container containing water and a lid plate covering the water container using a conveyor, and furthermore, A shelf for placing packaged products on the side and a dome-shaped bubble collecting element on the top of the shelf are provided, and the vacuum action inside the vacuum box (=the top of all the bubble collecting elements that are bubbles generated from the packaged product) is provided. The pinholes are efficiently detected by electrically catching the bubbles collected at the top of all the bubble collecting elements using a sensor.

Embodiments of the present invention will be described below based on the drawings.

In Figure 1, the conveyor (1) is a circular table type conveyor, and eight vacuum boxes (2
) has been attached. As shown in FIG. 2, the vacuum box (2) is composed of a container Vυ fixed to the upper surface of the table-shaped conveyor (1) and a lid plate l14 placed above the container I. The lid plate A is connected to a rod (1) via an arm uS, and the reciprocating movement of the rod I in the axial direction causes the mouth edge of the container (lυ) to touch and separate. A cylindrical material (15) is hung down from the center of the lower surface of the li4, and an umbrella-shaped foam collection element ([0] is fixed at the end of the intermediate material, and a packaged product is attached to the bottom of the foam collection element (16). A shelf board (17) on which is placed is fixed.The tube material is made of a transparent material, and as shown in FIG. A communicating passage (11) is formed, and airtight chambers UQclD are formed on both sides of the tube (151), and a sensor shift consisting of a phototube (22a) and a light receiving tube (22b) is installed in these airtight chambers. Furthermore, each vacuum box (21
+21... are connected to each hose (7! The other end is connected to the rotary pulp tZ3 provided at the center of the conveyor (1)) with one end connected to each cover plate (121), and the valve and the vacuum pump ( (not shown) are connected.

The illustrated embodiment is constructed as described above, and its operation will be explained below.

Water is supplied to each container Uυ from the water supply pipe (25) to a predetermined water level. The conveyor (1) is then continuously rotated clockwise. The competition 3 is placed on the F side of the conveyor (1).
- The rod I, which is mounted on a cam (not shown) provided in the opposite direction, moves up and down following the shape of the cam, and the cover plate (one is moved up and down, but in Fig. ,D,E.

At three locations, the lid plate opens the container (1υ), and at other locations, the lid plate and container are in close contact with each other.Then, the rotary pulp (
The second floor is hose c! 4, the sealed vacuum box is connected to a vacuum pump. Therefore, sealed packaged products @ are placed on the same shelf from position D to position E as shown in FIG. When the cover plate circle is lowered by the rotation of the conveyor (1) and the vacuum box is sealed, '! As shown in If13, the packaged product ■ is also submerged in water (B). If there are pinholes in the packaged product ■, air bubbles will be generated from them, but since the air pressure inside the vacuum box (2) is lowered by the action of the vacuum pump, air bubbles will also be generated from smaller pinholes. . When the bubbles are concentrated at the center of the bubble umbrella element t16) and caught by the phototube device, the generation of the bubbles is notified to the outside by an electric signal. Note that when the pressure inside the vacuum box is lowered, the air film on the surface of the packaged product becomes bubbles and rises; however, between this type of bubbles and the bubbles generated from the holes in the bottle, the latter naturally have a larger volume. The sensor t24 is adjusted in advance so as to detect only bubbles of a certain amount or more.

In addition to the phototube, the sensor 4 can also use a device that catches air bubbles using ultra-frequency waves. At the same time as the lid plate is opened at point C, the packaged products that have been inspected are taken out to the outside and sorted, and a new packaged product is supplied in their place.

If the degree of vacuum is 760'3; Hgl2 is too close, water (B)
Since the water (B) causes a boiling phenomenon and its bubbles are caught by sensors, it goes without saying that the degree of vacuum in the vacuum box should be controlled within a range that does not allow the water (B) to boil.

As mentioned above, the present invention circulates a large number of vacuum boxes (2) containing water using a conveyor (1), and the air pressure inside the vacuum box is adjusted to the pressure difference (2) generated from the pinhole in the packaged product (2). The air bubbles are collected in one place by the collecting umbrella element ue, and these air bubbles are caught by a sensor (7!) and taken out as an electric signal, so the part where the vacuum box opens is used to collect the air bubbles in one place. By supplying packaged products one after another, packaged products with pinholes are automatically detected, which has the effect of efficiently sorting out packaged products with pinholes with fewer workers.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a view taken along the line U--N of the previous figure, and FIG. 3 is a partially enlarged view for explaining the operation of the previous figure. ■...Packaged products. (B)...Water. (1)...Conveyor. (2)...Vacuum box. μυ...container. u21... Lid plate. 0 yen...Cylinder material. (16)...Umbrella element. Uη...Shelf. (2) Sensor. Ke... Rotary valve. 71

Claims (1)

[Claims] A conveyor (1) circulates a large number of vacuum boxes (2) each consisting of a container (ul) containing water and a lid plate 1121 covering it.
Each vacuum box is sealed in a predetermined range during one rotation to reduce the internal pressure, and in other ranges, the lid plate is flipped upward to open the vacuum box, and the vacuum box is opened. When the packaged product is being used, the packaged product is placed on the shelf U7J fixed through the lower part of the lid plate (a dome-shaped umbrella element μ), and the packaged product is submerged in the water in the sealed area of the vacuum box. , a method for detecting pinholes in packaged products, in which air bubbles squared are attached to the top of the bubble collecting umbrella element (2), and the air bubbles are caught at the top of the bubble collecting umbrella element and taken out as an electrical signal. .