CA2572028A1 - Inspection system for bottles or other containers - Google Patents
Inspection system for bottles or other containers Download PDFInfo
- Publication number
- CA2572028A1 CA2572028A1 CA 2572028 CA2572028A CA2572028A1 CA 2572028 A1 CA2572028 A1 CA 2572028A1 CA 2572028 CA2572028 CA 2572028 CA 2572028 A CA2572028 A CA 2572028A CA 2572028 A1 CA2572028 A1 CA 2572028A1
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- Prior art keywords
- inspection
- inspection system
- bottle
- bottles
- station
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- 238000007689 inspection Methods 0.000 title claims abstract description 72
- 238000012546 transfer Methods 0.000 claims abstract description 15
- 230000007246 mechanism Effects 0.000 claims abstract description 12
- 238000001514 detection method Methods 0.000 claims description 16
- 238000012360 testing method Methods 0.000 description 43
- 238000000034 method Methods 0.000 description 12
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000007789 sealing Methods 0.000 description 4
- 230000000712 assembly Effects 0.000 description 3
- 238000000429 assembly Methods 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 240000004859 Gamochaeta purpurea Species 0.000 description 1
- 241000845077 Iare Species 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- 229920005372 Plexiglas® Polymers 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 238000000071 blow moulding Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002372 labelling Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000010408 sweeping Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000009966 trimming Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
- 230000003245 working effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G15/00—Arrangements for check-weighing of materials dispensed into removable containers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
- G01M3/32—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Examining Or Testing Airtightness (AREA)
Abstract
An inspection system comprises at least one inspection station inspecting each received container and a rotating transfer carriage receiving containers to be inspected in series from a conveying mechanism. The transfer carriage slides each received container from the conveying mechanism to the at least one inspection station and once inspected, slides each container back to the conveying mechanism.
Description
INSPECTION SYSTEM FOR BOTTLES OR OTHER CONTAINERS
Field of the invention The present Invention relates generally to inspection systems and in particular to an inspection system for bottles or other containers.
Background of the Inyention Systems to inspect bottles and other containers are well known in the art and many variations have been considered. For example, U.S.
Patent No. 6,473,169 to Dawley et al. discloses an integrated leak and vision inspection system for inspecting bottles or other containers for manufacturing defects. The system comprises a series of visual inspection stations with cameras and lighting that are integrated onto a rotary inspection system for on-line inspection of containers. A microprocessor In data communication with each of the inspection stations receives and analyzes image data of the particular area or parameter of each container being inspected or tested, and generates data relating to the container based upon predetenrined criteria.
The stations are arranged to provide an integrated and fully automated and efficient inspection system. In the preferred embodiment, the system is structured with a first station integrated with an entry starwheel to inspect the top seal surface of the container. As the container moves out of the starwheel, a probe from a leak test assembly seals the container opening and the container is tested for leaks as it moves on a main tumtable into and through a second station to visually inspect the neck finish. The container is then transported on the turntable to a third station integrated with an exit starwheel to visually inspect the base of the container. The exit starwheel shifts the container onto the line conveyor to a reject station, which removes any containers that are below the set standards.
U.S. Patent No. 5,571,949 to MacLaughlin discloses a leak detection device including a container-rotating disc mounted for rotation about a rotation axis. Multiple container-supporting test heads are mounted to the disc for rotation about the rotation axis. Each test head includes a sealing assembly supported by a first cam follower and comprising a cylinder and a piston supported by a second cam fnilower and received in the cylinder. First I
Field of the invention The present Invention relates generally to inspection systems and in particular to an inspection system for bottles or other containers.
Background of the Inyention Systems to inspect bottles and other containers are well known in the art and many variations have been considered. For example, U.S.
Patent No. 6,473,169 to Dawley et al. discloses an integrated leak and vision inspection system for inspecting bottles or other containers for manufacturing defects. The system comprises a series of visual inspection stations with cameras and lighting that are integrated onto a rotary inspection system for on-line inspection of containers. A microprocessor In data communication with each of the inspection stations receives and analyzes image data of the particular area or parameter of each container being inspected or tested, and generates data relating to the container based upon predetenrined criteria.
The stations are arranged to provide an integrated and fully automated and efficient inspection system. In the preferred embodiment, the system is structured with a first station integrated with an entry starwheel to inspect the top seal surface of the container. As the container moves out of the starwheel, a probe from a leak test assembly seals the container opening and the container is tested for leaks as it moves on a main tumtable into and through a second station to visually inspect the neck finish. The container is then transported on the turntable to a third station integrated with an exit starwheel to visually inspect the base of the container. The exit starwheel shifts the container onto the line conveyor to a reject station, which removes any containers that are below the set standards.
U.S. Patent No. 5,571,949 to MacLaughlin discloses a leak detection device including a container-rotating disc mounted for rotation about a rotation axis. Multiple container-supporting test heads are mounted to the disc for rotation about the rotation axis. Each test head includes a sealing assembly supported by a first cam follower and comprising a cylinder and a piston supported by a second cam fnilower and received in the cylinder. First I
and second annular cams are mounted above the disc to operate the first and second cam followers, respectively, such that the sealing assemblies and the pistons are moved between respective upper and lower positions as the disc rotates with respect to the cams. The cams are shaped to press the sealing assemblies against the containers, to raise the pistons to draw a partial vacuum in the containers, and then to lift the sealing assemblies and any sealed containers for a vacuum test.
U.S. Patent No. 4,019,370 to Aliocco, Jr. discloses a leak testing device comprising reciprocable test heads disposed over a conveyer and associated lateral ejectors on one side of the conveyor. The leak testing device receives bottles from the conveyer and supports the battles using movable side gates so that the bottles are registered with the test heads. The test heads are lowered into air tight communication with the mouths of the bottles and a constant vqiume of pressurized air is discharged Into each bottle from a reservoir. When a defective bottle is detected, the associated side gate is moved to a clearance position allowing the defective bottie to be ejected.
U.S. Patent No. 4,184,362 to Standley et al. discloses an apparatus and method for detecting leaks at a fast rate in plastic bottles or similar containers wherein the bott{es are secured in a multipiic'rty of open pocket members and arranged in a piurality of rows on a rotatable turret. The rotating turret comprises a multiplicity of wheels having a multiplicity of pockets each which index through a sequence of different positions. A
detecting gas is introduced into the bottles and the bottles are subsequently moved to a detecting station where a mass spectrometer is activated by gas leaking from the bottles. In a preferred manner, air is utilized to effect a sweeping action over the botties to move leaking gas in the direction of the mass spectrometer. Air is also utilized to purge leaking gas from the pockets.
In order to detect leaking bottles/containers, many leak detection stations a pressure decay method In order to detect non-sealed or leaky botfiles. During this method, the bottle under test is pressurized to a certain level and then the drop in pressure is measured as a function of time. If the pressure drop at the end of the allocated test time exceeds a threshold value, the bottle is assumed to be leaky and is rejected. As will be appreciated, this pressure decay method is very attractive due to its simplicity and relatively low cost. Unfortunately this leak detection methodology has disadvantages.
Unfortunately, the accuracy by which this method is able to detect leaky bottles is fairly low, generally speaking, and this fact significantly limits the area of applications. As will be appreciated, there is a strong trend in industry for less expensive and more reliable testing methods. The everlasting quest for better and less expensive product necessities faster production rates, which of course translate into reduced test times for pressure decay thus further reducing accuracy. Therefore, leak flow rates of 1 D" to 10"3 cm3/min to be practically achievable at given production rate.
Another disadvantage of leak detection stations that employ the pressure decay method results from the fact that the initial low cost, is often offset by maintenance costs due to special, custom-made electronics and low end pressure transducers that are typically required in such stations.
Although the above-identified references disclose inspection systems, those of skill in the art will appreciate that improvements are desired.
It is therefore an object of the present invention to provide a novel inspection system.
Surnrnary-of the lnyention Accordingly, in one aspect there is provided an inspection system comprising:
at least one inspection station inspecting each received container; and a rotating transfer carriage receiving containers to be inspected in series from a conveying mechanism, said transfer carriaga sliding each received container from said conveying mechanism to said at least one inspection station and once inspected, sliding each container back to said conveying mechanism.
..Q._ Brief descrition of the Embodiments Embodiments wilf now be described more fuliy with reference to the accompanying drawings in which:
Figure 1 is an isometric view of an inspection system;
Figure 2 is a front elevatlonal view of the inspection system of Figure 1;
Figure 3 is an and elevational view of the inspection system of Figure 1;
Figure 4 is an isometric view of the inspection system of Figurei 1 in a partially opened condition;
Figure 5 Is a top view of the inspection system of Figure 1 in the partially opened condition;
Figure 6 Is a top view of the inspection system of Figure 1 in a fully opened condition;
Figure 7 shows pressure versus time graphs;
Figure 8 is a flowchart showing the steps performed during leak detection;
Figure 9 is an isometric view of an altemative inspection system;
Figure 10 is a front elevational view of the inspection system of Figure 9;
Figure 11 is a top view of the inspection system of Figure 9;
DetMfied Descriution of the Embodiments Turning now to Figures 1 to 6, an inspection system for bottles or other containers (hereinafter "bottles") is shown and is generally identified by reference numera150. As can be seen, inspection system 50 comprises a box-like main frame 52 mounted on a base frame 54. The base frame 54 comprises a pair of laterally spaced beams 56 spanned by a centrally positioned crossbar 58. A pair of legs 60 depends from each beam 56. Each leg 60 is positioned adjacent an opposite end of the beam 56 and supports a wheel 62. The wheels 62 are typically in contact with a ground surface and support the legs 60 slightly above the ground surface allowing the inspection system 50 to be readily moved. A jack 64 is mounted on each leg 60. The jacks 64 are moveable downwardly into contact with the ground surface thereby to lift the wheels 62 from the ground surface and condition the inspection system 50 to a parked condition.
The main frame 52 comprises a plurality of upright posts 70 mounted on the beams 58. A C-shaped boom 72 extends from one top comer of the main frame 52 and supports an operator control console 76. An electrical cabinet 80 is fixedly mounted on the rear of the main frame 52 and houses a controller. An inspection cabinet 82 is pivotally mounted on the front of the main frame 52 between open and closed positions. In this embodiment, the inspection cabinet surrounds a plurality of inspection stations as will be described. The inspection cabinet 82 has plexiglass panes so that the inner workings of the inspection cabinet are visible. The inspection cabinet 82 is disposed above a conveyer 90. In this manner, bottles travelling along the conveyer 90 are received by the inspection cabinet 82 in series through a bottle inlet 84 in one side of the inspection cabinet, subjected to inspection by the inspection stations before exiting the inspection cabinet 82 fihrough a bottle outlet 86 in the opposite side of the inspection cabinet via ttie conveyer 90.
Bottle guides 100 and 102 are associated with the bottle inlet 84 and boitfe outlet 86. tn particular, bottle guide 100 extends through the b.ottle inlet 84 above the conveyer 90 to guide movement of bottles into the inspection cabinet 82. Bottle guide 102 extends through the bottle outlet 86 above the cxmveyer 90 to guide movement of botfiles leaving the inspection cabinet 82.
Sensors 108 are positioned adjacent the bottle guide 84 to detect the orientation of bottles entering the inspection cabinet 82. A nozzle is positioned downstream of the sensors on one side of the conveyer and communicates with a pressurized air source. A discharge chute 110 is positioned on the other side of the conveyer 90 opposite the nozzle. If a bottle passes by the sensors in the improper orientation, the sensors generate signals which result in a jet of air being discharged by the nozzle thereby to push the bottle off of the conveyer 90 and onto the discharge chute 110. A
discharge chute 112 is also positioned to one side of the conveyer 90, upstream of the bottle guide 102. The discharge chute 112 receives bottles that do not pass inspection.
A transfer c2rriage 120 is centrally disposed within the inspection cabinet 82 and is positioned above the conveyer 90. The transfer camage receives bottles in serles from the conveyer via the bottle guide 100 and moves the botties through the inspection stations in succession. As each bottle passes through the last inspection station, the bottle Is either pushed onto the conveyer 90, if the bottie passes inspection, or is directed onto the discharge chute 112 if the bottle fails inspection.
The transfer carriage in this embodiment comprises a wheel 130 having a plurality of radial spokes 132. The spaces between adjacent spokes define nests 134 to receive botttes. Each nest is bordered by three sides, namely a back wall, a leading wall and a trailing push wall. The wheel is mounted on one end of an upright shaft 136. The other end of the shaft is coupled, through a reduction gearbox 138 mounted on the main frame 52, to a stepper motor 140.
A support table 150 having a top slide surface is positioned to one side of the conveyer 90 beneath the wheel. The top slide surface of the support table is generally in the same plane as that of the conveyer to facilitate sliding movement of bottles as they are moved from the conveyer to the inspection stations and then back to the conveyer. In this embodiment, as a single conveyor 90 is employed, the wheel moves the bottles in an accurate path that circumscribes 180 degrees.
ln this embodiment, the inspection stations 50 comprises a leak detection station and a weigh station. Of course, other primary stations such as for example, a vision inspection station and one or more secondary stations such as for example a machining stations, a flame treatment station and a labelling station. The leak detection and weight stations are positioned at circumferentially spaced locations above the support table thereby to enable the transfer carriage to deliver each bottle to the stations in succession as the wheel is rotated by the stepper motor.
The leak detection station comprises a generally vertical post mounted on a bracket 160. The post supports a pneumatic test head cylinder 170. The bracket is slidably adjustable along the post in order to adjust the height of the bracket and hence, the pneumatic test head cylinder above the support table. The test head cylinder accommodates a reciprocating rod having a test head 172 at one end. The test head comprises a seal to contact and form a seal with the neck of each bottle to be tested when the rod is extended. The test head and Its seal have a round shape. A pump hole is provided through the seal and the test head. The pump hole communicates with the inner chamber of the test head. The inner chamber of the test head is connected to a pump/shut-off valve and to a pressure transducer via hoses.
Pump/shut-off valve communicates with a pressurized air source.
The pump/shut-off valve allows air at regulated pressure from the source to be pumped into the bottle being tested and then sealed in order to allow the pressure transducer to measure the pressure decay over a period of time. Figure 7 shows the pressure decay for both the prior art and subject leak testing methodologies. The support table is perforated beneath the test head cylinder. A vacuum source is positioned beneath the support table at the perforations and creates a vacuum that is sufficiently strong to support the bottle being tested in a stable manner thereby to inhibit the bottle from moving as the rod brings the test head into engagement with the neck of the bottle.
The weigh station comprises a general horizontal weigh platform having an upper surface mounted generally flush with the top surface of the support table. The width of the weigh platform is equal the width of each nest of the wheel. The weigh platform is mounted on a load cell which generates an electrical signal proportional to the weight of the bottle supported thereon.
To deal with the disadvantages associated with conventional pressure decay inspection methods, the leak detecting station, the inspection system controls air flow and uses software routines that run on the controller to measure the rate of pressure rise anticipating the closing of the air pump/shut-off valve. The result is a more linear-like characteristic and lower overpressure peak. If the measured pressure at the end of the allocated test time does not reach an expected fill test pressure signifying an obviously bad bottle i.e. one with a big leak, an alarm is sounded.
The controller constantly monitors the resutis of successful pressure tests and recalculates the expected test pressure and the standard deviation d, lf the measured pressure at the end of the settle time falls outside of a defined range, an alarm is sounded. This criterion for rejection is very useful in that it allows situations when changes in production (blow-molding, trimming, flame-treatment, etc) have changed the properties of the botHes slightly, but the bottles are still acceptable, quality-wise. The above test avoids the need to re-adjust the leak detection station every time such production process change happens, because the leak detection station automatically adjusts the average values and deviation accordingly. Another benefit is that it assures consistency in testing conditions for all bottles as significant differences in test pressure are not permitted If the drop in pressure at the end of the test time is higher than a threshold level signifying a leaky bottle, an alarm is sounded. As will be appreciated, the above leak detecting procedure employs three measurements, making the leak detection system superior in detecting different leaking phenomena. Figure 8 shows the leak detection methodology.
The pressure transducer incorporates hi-end pressure sensors, which are equipped with built-in amplifier and driver circuitry. Analog PLC
modules with up to 4 A/D channels communicate with the pressure sensors.
The PLC modules are fast enough to provide multiple conversions sufficient for leak test applications. The PLC modules average 256 samples of pressure measurements in a very narrow dead band (10%). As a result, errors are reduced, which may be caused by internal or external noise, electromagnetic interference or other intermittent disturbances. In addition, the selection of a power supply easier becomes easier as there is no need for expensive power supply solutions.
-~-The controller in this embodiment is a Siemens S7-200 series, shoebox micro PLC. The PLCs are poweriul enough, to perform complete leak testing, calculations and I/0 control processing. Different test profiles can be saved by the controller.
Implementing a zero-pressure reference level, the testing results are relatively independent of the absolute pressure levels, which may drft over the time and when the bottle is initially sealed. Practically, this reduces the need for frequent system calibration.
The leak detection station provides reliable and accurate leak testing using a pressure decay method. Leaking holes of 0.005-0.007" iare reliably detected in fast testing cycles (less than 2 seconds), even at relatively low testing pressure of only 0.5 psi.
During operation, the conveyor feeds bottles into the inspection cabinet. If the wheel is stationary, the first bottle in the line enters the nest and is sensed by a presence sensor. The sensor in tum signals the controller which rotates the wheel. If the wheel is tuming at the moment when the bottle approaches it, the bottle is stopped by the outside circumference of the wheel until a nest is in line with the conveyor.
With the bottle in the nest, as the wheel turns it sweeps the bottle from the conveyor onto the support table thereby to position the bottle under the test head. The leak test procedure is then immediately commenced by lowering the test head and seal onto the bottle neck. After leak testing has been performed, the wheel is rotated thereby to deliver the bottle to the weigh station. Once weighed the wheel is rotated again thereby to return the bottle to the conveyor.
Failure to pass any of the quality control stations results In the bottle being rejected from the conveyor. This can be achieved in several ways, namely boities can be blown off of the conveyor by a jet of air as they pass in front of a reject photo detector or pushed away by a reject cylinder.
The bottle can also prevented for the exiting the nest resulting in continued travel of the bottle off the conveyer.
Figures 9 to 11 show an altemative embodiment of an inspection system. In this embodiment, the inspection system is designed to inspect larger bottles. Accordingly, as can be seen, the nests in the wheel are larger. The inspection system also includes a capping station downstream of the leak detection and weight stations. Capping station caps botties that have passed lnspection by both the leak detection and weigh stations. The capping station comprises a capping mechanism and a hopper that feed caps to the capping mechanism.
Although the transfer carriage is shown disposed above a continuous conveyor, those of skill in the art will appreciate that the transfer carriage may be disposed between an input conveyer and an exit conveyer.
In this case, the support table extends beneath the wheel to support bottles received by the nests. Also, the gearbox and motor used to rotate the wheel may be positioned either above or below the wheel.
Although embodiment have been described, those of skill in the art will appreciate that variations and modifications may be made without departing from the spirit and scope thereof as defined by the appended claims.
U.S. Patent No. 4,019,370 to Aliocco, Jr. discloses a leak testing device comprising reciprocable test heads disposed over a conveyer and associated lateral ejectors on one side of the conveyor. The leak testing device receives bottles from the conveyer and supports the battles using movable side gates so that the bottles are registered with the test heads. The test heads are lowered into air tight communication with the mouths of the bottles and a constant vqiume of pressurized air is discharged Into each bottle from a reservoir. When a defective bottle is detected, the associated side gate is moved to a clearance position allowing the defective bottie to be ejected.
U.S. Patent No. 4,184,362 to Standley et al. discloses an apparatus and method for detecting leaks at a fast rate in plastic bottles or similar containers wherein the bott{es are secured in a multipiic'rty of open pocket members and arranged in a piurality of rows on a rotatable turret. The rotating turret comprises a multiplicity of wheels having a multiplicity of pockets each which index through a sequence of different positions. A
detecting gas is introduced into the bottles and the bottles are subsequently moved to a detecting station where a mass spectrometer is activated by gas leaking from the bottles. In a preferred manner, air is utilized to effect a sweeping action over the botties to move leaking gas in the direction of the mass spectrometer. Air is also utilized to purge leaking gas from the pockets.
In order to detect leaking bottles/containers, many leak detection stations a pressure decay method In order to detect non-sealed or leaky botfiles. During this method, the bottle under test is pressurized to a certain level and then the drop in pressure is measured as a function of time. If the pressure drop at the end of the allocated test time exceeds a threshold value, the bottle is assumed to be leaky and is rejected. As will be appreciated, this pressure decay method is very attractive due to its simplicity and relatively low cost. Unfortunately this leak detection methodology has disadvantages.
Unfortunately, the accuracy by which this method is able to detect leaky bottles is fairly low, generally speaking, and this fact significantly limits the area of applications. As will be appreciated, there is a strong trend in industry for less expensive and more reliable testing methods. The everlasting quest for better and less expensive product necessities faster production rates, which of course translate into reduced test times for pressure decay thus further reducing accuracy. Therefore, leak flow rates of 1 D" to 10"3 cm3/min to be practically achievable at given production rate.
Another disadvantage of leak detection stations that employ the pressure decay method results from the fact that the initial low cost, is often offset by maintenance costs due to special, custom-made electronics and low end pressure transducers that are typically required in such stations.
Although the above-identified references disclose inspection systems, those of skill in the art will appreciate that improvements are desired.
It is therefore an object of the present invention to provide a novel inspection system.
Surnrnary-of the lnyention Accordingly, in one aspect there is provided an inspection system comprising:
at least one inspection station inspecting each received container; and a rotating transfer carriage receiving containers to be inspected in series from a conveying mechanism, said transfer carriaga sliding each received container from said conveying mechanism to said at least one inspection station and once inspected, sliding each container back to said conveying mechanism.
..Q._ Brief descrition of the Embodiments Embodiments wilf now be described more fuliy with reference to the accompanying drawings in which:
Figure 1 is an isometric view of an inspection system;
Figure 2 is a front elevatlonal view of the inspection system of Figure 1;
Figure 3 is an and elevational view of the inspection system of Figure 1;
Figure 4 is an isometric view of the inspection system of Figurei 1 in a partially opened condition;
Figure 5 Is a top view of the inspection system of Figure 1 in the partially opened condition;
Figure 6 Is a top view of the inspection system of Figure 1 in a fully opened condition;
Figure 7 shows pressure versus time graphs;
Figure 8 is a flowchart showing the steps performed during leak detection;
Figure 9 is an isometric view of an altemative inspection system;
Figure 10 is a front elevational view of the inspection system of Figure 9;
Figure 11 is a top view of the inspection system of Figure 9;
DetMfied Descriution of the Embodiments Turning now to Figures 1 to 6, an inspection system for bottles or other containers (hereinafter "bottles") is shown and is generally identified by reference numera150. As can be seen, inspection system 50 comprises a box-like main frame 52 mounted on a base frame 54. The base frame 54 comprises a pair of laterally spaced beams 56 spanned by a centrally positioned crossbar 58. A pair of legs 60 depends from each beam 56. Each leg 60 is positioned adjacent an opposite end of the beam 56 and supports a wheel 62. The wheels 62 are typically in contact with a ground surface and support the legs 60 slightly above the ground surface allowing the inspection system 50 to be readily moved. A jack 64 is mounted on each leg 60. The jacks 64 are moveable downwardly into contact with the ground surface thereby to lift the wheels 62 from the ground surface and condition the inspection system 50 to a parked condition.
The main frame 52 comprises a plurality of upright posts 70 mounted on the beams 58. A C-shaped boom 72 extends from one top comer of the main frame 52 and supports an operator control console 76. An electrical cabinet 80 is fixedly mounted on the rear of the main frame 52 and houses a controller. An inspection cabinet 82 is pivotally mounted on the front of the main frame 52 between open and closed positions. In this embodiment, the inspection cabinet surrounds a plurality of inspection stations as will be described. The inspection cabinet 82 has plexiglass panes so that the inner workings of the inspection cabinet are visible. The inspection cabinet 82 is disposed above a conveyer 90. In this manner, bottles travelling along the conveyer 90 are received by the inspection cabinet 82 in series through a bottle inlet 84 in one side of the inspection cabinet, subjected to inspection by the inspection stations before exiting the inspection cabinet 82 fihrough a bottle outlet 86 in the opposite side of the inspection cabinet via ttie conveyer 90.
Bottle guides 100 and 102 are associated with the bottle inlet 84 and boitfe outlet 86. tn particular, bottle guide 100 extends through the b.ottle inlet 84 above the conveyer 90 to guide movement of bottles into the inspection cabinet 82. Bottle guide 102 extends through the bottle outlet 86 above the cxmveyer 90 to guide movement of botfiles leaving the inspection cabinet 82.
Sensors 108 are positioned adjacent the bottle guide 84 to detect the orientation of bottles entering the inspection cabinet 82. A nozzle is positioned downstream of the sensors on one side of the conveyer and communicates with a pressurized air source. A discharge chute 110 is positioned on the other side of the conveyer 90 opposite the nozzle. If a bottle passes by the sensors in the improper orientation, the sensors generate signals which result in a jet of air being discharged by the nozzle thereby to push the bottle off of the conveyer 90 and onto the discharge chute 110. A
discharge chute 112 is also positioned to one side of the conveyer 90, upstream of the bottle guide 102. The discharge chute 112 receives bottles that do not pass inspection.
A transfer c2rriage 120 is centrally disposed within the inspection cabinet 82 and is positioned above the conveyer 90. The transfer camage receives bottles in serles from the conveyer via the bottle guide 100 and moves the botties through the inspection stations in succession. As each bottle passes through the last inspection station, the bottle Is either pushed onto the conveyer 90, if the bottie passes inspection, or is directed onto the discharge chute 112 if the bottle fails inspection.
The transfer carriage in this embodiment comprises a wheel 130 having a plurality of radial spokes 132. The spaces between adjacent spokes define nests 134 to receive botttes. Each nest is bordered by three sides, namely a back wall, a leading wall and a trailing push wall. The wheel is mounted on one end of an upright shaft 136. The other end of the shaft is coupled, through a reduction gearbox 138 mounted on the main frame 52, to a stepper motor 140.
A support table 150 having a top slide surface is positioned to one side of the conveyer 90 beneath the wheel. The top slide surface of the support table is generally in the same plane as that of the conveyer to facilitate sliding movement of bottles as they are moved from the conveyer to the inspection stations and then back to the conveyer. In this embodiment, as a single conveyor 90 is employed, the wheel moves the bottles in an accurate path that circumscribes 180 degrees.
ln this embodiment, the inspection stations 50 comprises a leak detection station and a weigh station. Of course, other primary stations such as for example, a vision inspection station and one or more secondary stations such as for example a machining stations, a flame treatment station and a labelling station. The leak detection and weight stations are positioned at circumferentially spaced locations above the support table thereby to enable the transfer carriage to deliver each bottle to the stations in succession as the wheel is rotated by the stepper motor.
The leak detection station comprises a generally vertical post mounted on a bracket 160. The post supports a pneumatic test head cylinder 170. The bracket is slidably adjustable along the post in order to adjust the height of the bracket and hence, the pneumatic test head cylinder above the support table. The test head cylinder accommodates a reciprocating rod having a test head 172 at one end. The test head comprises a seal to contact and form a seal with the neck of each bottle to be tested when the rod is extended. The test head and Its seal have a round shape. A pump hole is provided through the seal and the test head. The pump hole communicates with the inner chamber of the test head. The inner chamber of the test head is connected to a pump/shut-off valve and to a pressure transducer via hoses.
Pump/shut-off valve communicates with a pressurized air source.
The pump/shut-off valve allows air at regulated pressure from the source to be pumped into the bottle being tested and then sealed in order to allow the pressure transducer to measure the pressure decay over a period of time. Figure 7 shows the pressure decay for both the prior art and subject leak testing methodologies. The support table is perforated beneath the test head cylinder. A vacuum source is positioned beneath the support table at the perforations and creates a vacuum that is sufficiently strong to support the bottle being tested in a stable manner thereby to inhibit the bottle from moving as the rod brings the test head into engagement with the neck of the bottle.
The weigh station comprises a general horizontal weigh platform having an upper surface mounted generally flush with the top surface of the support table. The width of the weigh platform is equal the width of each nest of the wheel. The weigh platform is mounted on a load cell which generates an electrical signal proportional to the weight of the bottle supported thereon.
To deal with the disadvantages associated with conventional pressure decay inspection methods, the leak detecting station, the inspection system controls air flow and uses software routines that run on the controller to measure the rate of pressure rise anticipating the closing of the air pump/shut-off valve. The result is a more linear-like characteristic and lower overpressure peak. If the measured pressure at the end of the allocated test time does not reach an expected fill test pressure signifying an obviously bad bottle i.e. one with a big leak, an alarm is sounded.
The controller constantly monitors the resutis of successful pressure tests and recalculates the expected test pressure and the standard deviation d, lf the measured pressure at the end of the settle time falls outside of a defined range, an alarm is sounded. This criterion for rejection is very useful in that it allows situations when changes in production (blow-molding, trimming, flame-treatment, etc) have changed the properties of the botHes slightly, but the bottles are still acceptable, quality-wise. The above test avoids the need to re-adjust the leak detection station every time such production process change happens, because the leak detection station automatically adjusts the average values and deviation accordingly. Another benefit is that it assures consistency in testing conditions for all bottles as significant differences in test pressure are not permitted If the drop in pressure at the end of the test time is higher than a threshold level signifying a leaky bottle, an alarm is sounded. As will be appreciated, the above leak detecting procedure employs three measurements, making the leak detection system superior in detecting different leaking phenomena. Figure 8 shows the leak detection methodology.
The pressure transducer incorporates hi-end pressure sensors, which are equipped with built-in amplifier and driver circuitry. Analog PLC
modules with up to 4 A/D channels communicate with the pressure sensors.
The PLC modules are fast enough to provide multiple conversions sufficient for leak test applications. The PLC modules average 256 samples of pressure measurements in a very narrow dead band (10%). As a result, errors are reduced, which may be caused by internal or external noise, electromagnetic interference or other intermittent disturbances. In addition, the selection of a power supply easier becomes easier as there is no need for expensive power supply solutions.
-~-The controller in this embodiment is a Siemens S7-200 series, shoebox micro PLC. The PLCs are poweriul enough, to perform complete leak testing, calculations and I/0 control processing. Different test profiles can be saved by the controller.
Implementing a zero-pressure reference level, the testing results are relatively independent of the absolute pressure levels, which may drft over the time and when the bottle is initially sealed. Practically, this reduces the need for frequent system calibration.
The leak detection station provides reliable and accurate leak testing using a pressure decay method. Leaking holes of 0.005-0.007" iare reliably detected in fast testing cycles (less than 2 seconds), even at relatively low testing pressure of only 0.5 psi.
During operation, the conveyor feeds bottles into the inspection cabinet. If the wheel is stationary, the first bottle in the line enters the nest and is sensed by a presence sensor. The sensor in tum signals the controller which rotates the wheel. If the wheel is tuming at the moment when the bottle approaches it, the bottle is stopped by the outside circumference of the wheel until a nest is in line with the conveyor.
With the bottle in the nest, as the wheel turns it sweeps the bottle from the conveyor onto the support table thereby to position the bottle under the test head. The leak test procedure is then immediately commenced by lowering the test head and seal onto the bottle neck. After leak testing has been performed, the wheel is rotated thereby to deliver the bottle to the weigh station. Once weighed the wheel is rotated again thereby to return the bottle to the conveyor.
Failure to pass any of the quality control stations results In the bottle being rejected from the conveyor. This can be achieved in several ways, namely boities can be blown off of the conveyor by a jet of air as they pass in front of a reject photo detector or pushed away by a reject cylinder.
The bottle can also prevented for the exiting the nest resulting in continued travel of the bottle off the conveyer.
Figures 9 to 11 show an altemative embodiment of an inspection system. In this embodiment, the inspection system is designed to inspect larger bottles. Accordingly, as can be seen, the nests in the wheel are larger. The inspection system also includes a capping station downstream of the leak detection and weight stations. Capping station caps botties that have passed lnspection by both the leak detection and weigh stations. The capping station comprises a capping mechanism and a hopper that feed caps to the capping mechanism.
Although the transfer carriage is shown disposed above a continuous conveyor, those of skill in the art will appreciate that the transfer carriage may be disposed between an input conveyer and an exit conveyer.
In this case, the support table extends beneath the wheel to support bottles received by the nests. Also, the gearbox and motor used to rotate the wheel may be positioned either above or below the wheel.
Although embodiment have been described, those of skill in the art will appreciate that variations and modifications may be made without departing from the spirit and scope thereof as defined by the appended claims.
Claims (6)
1. An inspection system comprising:
at least one inspection station inspecting each received container; and a rotating transfer carriage receiving containers to be inspected in series from a conveying mechanism, said transfer carriage sliding each received container from said conveying mechanism to said at least one inspection station and once inspected, sliding each container back to said conveying mechanism.
at least one inspection station inspecting each received container; and a rotating transfer carriage receiving containers to be inspected in series from a conveying mechanism, said transfer carriage sliding each received container from said conveying mechanism to said at least one inspection station and once inspected, sliding each container back to said conveying mechanism.
2. An inspection system according to claim 1 wherein said rotating transfer carriage slides each received container from said conveying mechanism to said at least one inspection station across a support table.
3. An inspection system according to claim 2 wherein each container is swept along an accurate path by said rotating transfer carriage.
4. An inspection system according to claim 3 wherein said accurate path circumscribes generally 180 degrees.
5. An inspection system according to any one of claims 1 to 4 comprising a plurality of inspection stations, said transfer carriage delivering said containers to the inspection stations successively.
6. An inspection system according to claim 5 wherein one of said inspection stations is a leak detection station
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2572028 CA2572028A1 (en) | 2006-12-22 | 2006-12-22 | Inspection system for bottles or other containers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2572028 CA2572028A1 (en) | 2006-12-22 | 2006-12-22 | Inspection system for bottles or other containers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2572028A1 true CA2572028A1 (en) | 2008-06-22 |
Family
ID=39551444
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2572028 Abandoned CA2572028A1 (en) | 2006-12-22 | 2006-12-22 | Inspection system for bottles or other containers |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2572028A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108482768A (en) * | 2018-03-14 | 2018-09-04 | 浙江金正检测有限公司 | The food cans air-tightness automatic checkout system of canned food |
| CN109655206A (en) * | 2018-12-24 | 2019-04-19 | 广东鑫美精密机械有限公司 | One kind is leaked hunting weighing all-in-one machine |
| CN113291783A (en) * | 2021-06-09 | 2021-08-24 | 东莞市冠佳电子设备有限公司 | Full-automatic electronic component material loading machine |
-
2006
- 2006-12-22 CA CA 2572028 patent/CA2572028A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108482768A (en) * | 2018-03-14 | 2018-09-04 | 浙江金正检测有限公司 | The food cans air-tightness automatic checkout system of canned food |
| CN109655206A (en) * | 2018-12-24 | 2019-04-19 | 广东鑫美精密机械有限公司 | One kind is leaked hunting weighing all-in-one machine |
| CN113291783A (en) * | 2021-06-09 | 2021-08-24 | 东莞市冠佳电子设备有限公司 | Full-automatic electronic component material loading machine |
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