JP5067552B2 - Pinhole inspection machine with self-diagnosis function - Google Patents

Description

  The present invention relates to a pinhole inspection machine with a self-diagnosis function, in particular, a pinhole detection of the pinhole inspection machine itself without introducing a test piece having a pseudo pinhole perforated on a conveyance line and without depending on the number of inspections. The present invention relates to a pinhole inspection machine with a self-diagnosis function that has a built-in self-diagnosis function capable of checking accuracy as appropriate.

Synthetic resin bottles, particularly PET bottles, have been produced in large quantities in recent years as containers for beverages, foods, and the like because they are lightweight and easy to handle.
In this PET bottle, first, a primary molded product called a preform is manufactured by injection molding or the like, then this preform is set in a predetermined mold, and heated to a temperature at which it can be oriented and stretched by heating means such as a heater, Next, a stretch rod for injecting high-pressure air is inserted into the preform and stretched biaxially with the stretch rod and the high-pressure air. In this way, the biaxial stretch blow molding method stretches a heated preform biaxially in a direction perpendicular to the axial direction with a stretching rod and pressurized air, so there are subtle differences in processing force (stretching force) and resin. There is a possibility that pinholes and the like are generated in the manufactured PET bottle due to the mixing of extremely small foreign matters into the material. Therefore, it is necessary to inspect whether or not defects such as pinholes have occurred on the PET bottle after blow molding. As an inspection method therefor, for the PET bottle gripped along the outer periphery of the main rotor, the pressure head is brought into contact with the bottle mouth to fill and seal the inside of the bottle, and the air sealed state Is known for a pinhole inspection method for determining whether or not a pinhole has occurred from the amount of pressure drop of the bottle internal pressure after the predetermined time has elapsed (for example, Patent Document 1 and Patent Document 1) 2).
In these inspection machines, there is no function (self-diagnosis function) to check the inspection accuracy (pinhole detection accuracy) of the inspection machine itself, and confirmation of the inspection accuracy of the inspection machine itself is left to the discretion of the user. .
The user periodically inserts test pieces with pseudo pinholes into the pinhole inspection machine, and when these test pieces are reliably rejected by the inspection machine, the pinhole inspection machine has the specified pinhole detection accuracy. It was judged that it was maintained. However, this type of inspection accuracy check requires not only a lot of labor and time for accuracy check work, but also because the hole diameter of the pseudo pinhole increases when the test piece is used multiple times, In order to check the detection accuracy, it was difficult to say that it was necessary to manufacture a test piece accurately drilled each time. In addition, it was difficult to put the test piece itself into the line that continuously conveys the PET bottle at a high speed.

JP 2004-205453 A JP 2002-310843 A

As described above, in the conventional pinhole inspection machine, when checking the inspection accuracy, it is necessary to set up (work) to set a test piece having a pseudo pinhole drilled in the transport line. In addition, a test piece for that purpose is also required. In addition, the diameter of the pseudo pinhole gradually increases in proportion to the number of times the test piece is used, and at the end it becomes considerably larger than the actual pinhole. As a result, the pinhole detection accuracy of the pinhole inspection machine is confirmed. There was a problem that it was difficult to do.
Therefore, the present invention has been made in view of the problems of the prior art, and does not depend on the number of inspections without inserting a test piece in which a pseudo pinhole is perforated in the conveyance line. It is an object of the present invention to provide a pinhole inspection machine with a self-diagnosis function that incorporates a self-diagnosis function that can appropriately check the pinhole detection accuracy of the inspection machine itself.

In order to achieve the above object, a pinhole inspection machine with a self-diagnosis function according to claim 1, wherein a predetermined amount of gas is sealed in a bottle and the bottle mouth is sealed, and the bottle internal pressure is lowered after a predetermined time has elapsed. It is a pinhole inspection machine that measures the amount and determines the presence or absence of a pinhole based on the measurement result, and has a branch line in the middle of the gas supply side line or pressure detection side line of the bottle, and a valve in the branch line An orifice serving as a pseudo pinhole is connected via the orifice , and the orifice is configured to have a variable hole diameter .
In the above-mentioned pinhole inspection machine with a self-diagnosis function, a predetermined amount of gas is introduced into the gas circuit through a normal bottle (without holes), and the gas supply valve is closed, whereby the gas is supplied to the bottle. Form a sealed state. Further, a gas supply line upstream of the bottle or a pressure detection line for detecting the bottle internal pressure is branched, and an orifice as a pseudo pinhole is provided in the branch line via a valve (self-diagnostic valve). Therefore, by opening the valve (self-diagnostic valve) of the branch line, it is possible to form a pseudo leak state as if a pinhole exists in the bottle and gas leaks through the pinhole. become. In other words, the above pinhole inspection machine makes it appear that a pseudo pinhole is formed in a normal bottle by connecting a test piece called an orifice to a circuit in which a normal bottle (without holes) is gas-sealed. The detection accuracy of the pinhole inspection machine is confirmed. This eliminates the need to put a test piece in which a pseudo pinhole is perforated in place of a normal bottle in the transport line, and as a result, all the labor and time involved in putting the test piece, including the creation of the test piece, are eliminated. It will be saved. Further, since a metal part called an orifice is used, the phenomenon that the hole diameter increases in proportion to the number of inspections does not occur.

In addition , since the orifice is configured such that the hole diameter is variable according to the purpose of inspection, it is possible to simulate (simulate) various assumed pinholes.

In the pinhole inspection machine with a self-diagnosis function according to claim 2 , the orifice is configured as a member constituting a part of the flow path of the branch line , and the orifice having a different hole diameter is configured to be replaceable with respect to the branch line. It was decided.
In the above-described pinhole inspection machine with a self-diagnosis function, various assumed pinholes can be simulated by replacing the orifice with another member having a different hole diameter.

According to the pinhole inspection machine with a self-diagnosis function of the present invention, a pinhole of the inspection machine itself can be used without introducing a test piece in which a pseudo pinhole is drilled in place of a normal bottle (without a hole) in the transport line. The detection accuracy can be confirmed as appropriate. This saves all of the labor and time associated with test piece insertion, including test piece creation. In addition, since the pseudo leak state of the bottle is formed by the orifice of the self-diagnosis valve provided in the gas supply side line or the pressure detection side line of the bottle, confirmation of pinhole detection accuracy does not depend on the number of inspections. In addition, various bottle pseudo-leak states can be easily formed by a variable-diameter orifice according to the purpose of the self-diagnostic valve inspection . For example, when the self-diagnostic valve is opened and the bottle is not discharged . As described above, it becomes easy to find defects such as the bottle discharge mechanism. As described above, since the inspection accuracy of the inspection machine itself (that the inspection function is not deteriorated) can be confirmed as appropriate, the quality of the pinhole inspection is improved. In addition, since a pseudo pinhole is reliably provided in the inspection circuit, all the bottles that are put into this inspection machine during the inspection of the inspection machine are out-of-order regardless of whether there is a pinhole in the bottle itself. It is judged and rejected from the inspection machine. At this time, if the bottle is determined to be a non-defective product and is not rejected by the inspection machine, it is possible to find out a problem that has occurred in the bottle removal mechanism of the inspection machine.

  Hereinafter, the present invention will be described in more detail with reference to embodiments shown in the drawings.

FIG. 1 is an explanatory view showing a main part of a pinhole inspection system 100 according to the present invention.
The pinhole inspection system 100 includes an air injector 10 that supplies air to the bottle 1 and outputs (feeds back) the bottle internal pressure, a gripper 2 that stabilizes the posture of the bottle 1 while gripping the neck of the bottle 1, an air Supply valve 3 for intermittently supplying air to the injector 10, self-diagnosis valve 4 for forming a pseudo leak state of the bottle 1, and pressure detection for measuring a pressure drop amount from a reference internal pressure after a predetermined time of the bottle 1 5, an air source 6 that stably supplies air regulated to a constant pressure downstream, an air supply line 7 that transfers air, a pressure detection line 8 that propagates pressure, a supply valve 3, and a self-diagnosis valve 4 is opened and closed, and when the pressure drop exceeds the threshold based on the signal from the pressure detector 5, the bottle 1 to be inspected is judged as an out product and discharged from the line. It is configured by including a control device 9 to issue so that instructions. Details of the self-diagnosis valve 4 and the pressure detection unit 5 will be described later with reference to FIGS. The “reference internal pressure of the bottle 1” is the internal pressure of the bottle 1 immediately after the supply valve 3 is closed.

  The bottle 1 is a synthetic resin bottle such as a PET bottle. After being blow-molded from a preform, the bottle 1 is gripped by a gripper 2 arranged at equal intervals on the outer periphery of the main wheel, and the air jet is in an upright state. It is transported directly below 10.

  The supply valve 3 and the self-diagnosis valve 4 are preferably electromagnetic valves from the viewpoint of responsiveness. Further, the supply valve 3 and the self-diagnosis valve 4 are so-called normal close valves that are controlled by the control device 9 and are opened for a predetermined ON time, and the others are kept closed.

  The self-diagnosis valve 4 has an orifice 41 at the outlet. The orifice 41 simulates the pinhole of the bottle 1. The details will be described later with reference to FIGS. 2 to 6. When the self-diagnosis valve 4 is opened, the air sealed in the bottle 1 flows out of the orifice 41 to the outside, and a pinhole is formed in the bottle 1. It exists and forms a pseudo leak state as if air leaks from the pinhole. At this time, the control device 9 determines that there is a leak from the pinhole of the bottle 1 based on the pressure drop amount of the bottle 1, drives the gripper 2 and discharges the bottle 1. Thus, by opening the self-diagnosis valve 4, so-called self-diagnosis can be performed in which the inspection accuracy of the pinhole inspection machine itself (inspection function is not deteriorated) is confirmed. In addition, the orifices are interchangeably attached so that the pinholes of the various bottles that can be assumed can be accurately simulated.

  The orifice 41 may be a variable orifice that includes, for example, a throttle mechanism and whose hole diameter continuously changes. Alternatively, a plurality of members that can be replaced with respect to the branch line may be provided, each having a different hole diameter. Furthermore, the means for varying the orifice diameter is not limited to these, and known means can be used as appropriate.

  The pressure detection unit 5 includes a pressure sensor that measures the internal pressure of the bottle 1 and a differential pressure sensor that measures the amount of pressure drop from the reference internal pressure after a predetermined time has elapsed.

  The air source 6 stably supplies air adjusted to a constant pressure within a range of, for example, 20 to 25 [kPa] by a pressure adjusting valve or a pressure reducing valve downstream.

  The air supply line 7 starts from the supply valve 3 and branches in two directions through a joint part in the middle thereof, and one end is connected to the supply port 13 and the other end is connected to the self-diagnosis valve 4.

  The pressure detection line 8 connects the pressure port 14 and the pressure detection unit 5. Moreover, the pressure detection line 8 has a joint part connecting the branch line in the middle. Therefore, the self-diagnosis valve 4 can be connected to this joint part in the same manner as the joint part provided in the air supply line 7 to check the inspection accuracy of the system before the pinhole inspection.

  The control device 9 controls opening and closing of the supply valve 3 and the self-diagnosis valve 4. Further, based on the pressure signal from the pressure detector 5, if the amount of pressure drop from the reference internal pressure after a certain time has exceeded a preset threshold, it is determined that a pinhole exists in the bottle 1, Bottle 1 is discarded.

  The air injector 10 includes a pressurizing head 11 that abuts against the air tightness at the bottle mouth, a main body 12 having an air supply passage 12a and a pressure detection passage 12b formed therein, The pressure port 13 serving as the introduction port, the pressure port 14 that outputs the internal pressure of the bottle 1, and the spring mechanism 15 that absorbs an impact when the pressure head 11 comes into contact with the bottle mouth portion are configured. Yes.

  The air injector 10 can be moved up and down by an elevating device (not shown). Therefore, when the air is supplied to the bottle 1, the elevating device lowers the pressure head 11 to contact the bottle mouth portion, while exhausting the air from the bottle 1 (releasing the air-sealed state). Raises the pressure head 11 and separates it from the bottle mouth. Further, the pressurizing head 11 may be constituted by an elastic body such as a synthetic rubber in order to secure a sealing property (sealing property) with the bottle mouth portion. Further, the air injector 10 may be provided with an alignment adjusting mechanism that corrects a deviation between the axis of the pressure head 11 and the axis of the bottle 1 together with or instead of the spring mechanism 15.

  FIG. 2 is an explanatory diagram showing the main parts of the self-diagnosis valve 4 and the pressure detector 5.

  The self-diagnosis valve 4 includes an orifice 41 at the outlet. The self-diagnosis valve 4 is normally closed and maintains the sealing performance of the bottle 1 together with the supply valve 3. Further, the orifice 41 is configured such that orifices having different hole diameters can be attached and detached so that pinholes of various bottles can be accurately simulated. Therefore, when the self-diagnosis valve 4 is opened, the air in the bottle 1 flows out through the orifice 41, and as a result, a pseudo leak state is formed as if the air leaks through the pinhole of the bottle 1. Will come to be. Therefore, if the leak inspection system itself is normal, it is determined that a pinhole is present in the bottle 1 from the amount of pressure drop caused by air outflow, and as a result, the bottle 1 is rejected.

  As described above, the self-diagnostic valve 4 eliminates the need to set the test piece in which the pseudo pinhole is drilled in the transport line in place of the bottle 1, and the pseudo leak state in which the pinholes of various bottles are accurately simulated. Self-diagnosis can be performed. Thereby, confirmation of the inspection accuracy of the pinhole inspection system is appropriately performed.

  The pressure detection unit 5 includes a pressure sensor 51 that constantly measures the internal pressure of the bottle 1, a differential pressure sensor 52 that measures a pressure drop amount from a reference internal pressure after the bottle 1 has elapsed for a fixed time, and a differential pressure sensor 52. And a differential pressure valve 53 for bringing the two chambers into communication / non-communication. As will be described later, the opening / closing operation of the differential pressure valve 53 is synchronized with the opening / closing operation of the supply valve 3. When the supply valve 3 is open (ON), the differential pressure valve 53 is simultaneously opened (ON). Thus, when the supply valve 3 is closed (OFF), the differential pressure valve 53 is simultaneously closed (OFF).

  The differential pressure sensor 52 has two chambers: a first chamber 52a that always communicates with the bottle 1 and a second chamber 52b that communicates with the bottle 1 only when the differential pressure valve 53 is ON. Therefore, the pressure in the first chamber 52a constantly monitors the internal pressure of the bottle 1. The second chamber 52b is not in communication with the bottle 1 and the second chamber 52b when the differential pressure valve 53 is OFF (the supply valve 3 is OFF). The pressure in the two chamber 52b indicates the internal pressure of the bottle 1 immediately after the supply valve 3 is turned off. Therefore, the pressure in the second chamber 52b becomes the reference internal pressure when measuring the amount of pressure drop after a fixed time has elapsed in the bottle 1. Therefore, the differential pressure sensor 52 is monitoring (the internal pressure of the bottle 1 immediately after the supply valve 3 is turned off) − (the internal pressure of the bottle 1 in real time) = the pressure drop amount of the bottle 1 after a lapse of time. become.

3 to 5 are explanatory diagrams showing the operation of the self-diagnosis valve 4 and the pressure detection unit 5.
First, as shown in FIG. 3, when the control device 9 opens (ON) the supply valve 3, the differential pressure valve 53 also opens (ON) at the same time, and the bottle 1, the first chamber 52 a of the differential pressure sensor 52, and the first pressure sensor 52. Air is supplied to the two chambers 52b. The inside of the bottle immediately after the introduction of air is in an excessive state in which air molecules collide violently, so that the temperature of the air rises. However, with the passage of time, the inside of the bottle approaches a steady state, and the body of the bottle swells outward. As a result, the internal pressure of the bottle 1 gradually decreases and converges to a constant pressure. At this time, the self-diagnosis valve 4 is closed (OFF).

  As shown in FIG. 4, after a certain ON time of the supply valve 3, that is, after a predetermined amount of air is supplied, the control device 9 turns off the supply valve 3 and the differential pressure valve 53. As a result, the first chamber 52a and the second chamber 52b are not communicated. The indicated value of the pressure sensor 51 at this time becomes a reference internal pressure for pressure drop measurement, and is used in a step of checking whether or not the reference internal pressure exceeds a predetermined threshold and determining the presence or absence of a pinhole. At this time, the pressure in the first chamber 52a and the pressure in the second chamber 52b are equal to each other, and as a result, the differential pressure sensor 52 indicates zero. At this time, the self-diagnosis valve 4 is closed (OFF).

  As shown in FIG. 5, the inside of the bottle 1 is in a steady state after a certain time has elapsed. If the bottle 1 does not have a defect such as a pinhole that impairs the airtightness of the bottle, only a slight pressure drop mainly due to a temperature drop occurs. Accordingly, a slight pressure difference corresponding to the pressure drop is generated between the first chamber 52a and the second chamber 52b of the differential pressure sensor 52. At this time, the self-diagnosis valve 4 is closed (OFF).

  As shown in FIG. 6, when the indicated value of the differential pressure sensor 52 (the amount of pressure drop from the reference internal pressure) does not exceed a predetermined threshold value (when there is no pinhole in the bottle 1), the control device 9 The diagnostic valve 4 is opened (ON). As a result, the air in the bottle 1 gradually flows out through the orifice 41, and a pseudo-leak state is formed as if the air is leaking from the pinhole of the bottle 1.

  As described above, according to the pinhole inspection system 100, the pinhole detection accuracy of the inspection system itself can be appropriately checked without introducing a test piece having a pseudo pinhole perforated in place of the bottle 1 in the transport line. Will be able to. This saves all of the labor and time associated with test piece insertion, including test piece creation. Moreover, since the pseudo leak state of the bottle 1 is formed by the orifice 41 of the self-diagnosis valve 4 provided in the air supply line 7 of the bottle 1, confirmation of pinhole detection accuracy does not depend on the number of inspections. In addition, since the pseudo-leak state of the bottle 1 can be easily formed by the orifice 41 of the self-diagnosis valve 4, the bottle 1 is not discharged when the self-diagnosis valve 4 is open (ON), for example. It is easy to find defects such as the discharge mechanism. As described above, since the inspection accuracy of the inspection system itself (inspection function is not deteriorated) can be confirmed as appropriate, the quality of the pinhole inspection is improved.

  In the above embodiment, air is used as the bottle pinhole inspection gas. However, the present invention is not limited to this, and an inert gas such as helium and nitrogen or a mixed gas of these and air may be used. .

  The pinhole inspection system of the present invention is a bottle pinhole inspection machine that determines the presence or absence of a pinhole in a bottle by sealing the gas with respect to the bottle of the conveyance line and measuring the amount of decrease in the bottle internal pressure after a lapse of a certain time. It can be suitably applied.

It is explanatory drawing which shows the principal part of the pinhole inspection system which concerns on this invention. It is explanatory drawing which shows the principal part of a self-diagnosis valve and a pressure detection part. It is explanatory drawing which shows operation | movement of the self-diagnosis valve and pressure detection part immediately after a supply valve is opened. It is explanatory drawing which shows operation | movement of the self-diagnosis valve and pressure detection part immediately after a supply valve is closed. It is explanatory drawing which shows operation | movement of the self-diagnosis valve and a pressure detection part after a supply valve is closed and a fixed time passes. It is explanatory drawing which shows operation | movement of the pressure detection part immediately after a self-diagnosis valve is opened.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bottle 2 Gripper 3 Supply valve 4 Self-diagnosis valve 5 Pressure detection part 6 Air source 7 Air supply line 8 Pressure detection line 9 Control apparatus 10 Air injector 11 Pressure head 12 Main body 13 Supply port 14 Pressure port 15 Spring mechanism 100 Pin Hall inspection system

Claims (2)

It is a pinhole inspection machine that seals the bottle mouth with a predetermined amount of gas, measures the amount of decrease in the bottle internal pressure after a certain period of time, and determines the presence or absence of pinholes based on the measurement results. A branch line is provided in the middle of the gas supply line or pressure detection side line of the bottle, and an orifice as a pseudo pinhole is connected to the branch line via a valve .
A pinhole inspection machine with a self-diagnosis function , wherein the orifice is configured to have a variable hole diameter . The orifice is configured as a member that forms part of the flow path of the branch line ,
Self-diagnosis function pinhole inspection apparatus according to claim 1 having a pore diameter different orifice to the branch lines you characterized in that it is configured to be interchangeable.

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