US2593311A - Apparatus for detecting the presence of foreign bodies in transparent containers - Google Patents

Description

April 1952 P. M. JOHNSON .1-:'r AL APPARATUS FOR DETECTING THE PRESENCE OF FOREIGN BODIES IN TRANSPARENT CONTAINERS 2 SHEETS-SHEET 1 Filed April 5, 1948 April 15, 1952 P. M. JOHNSON ETAL 2,593,311

APPARATUS FOR DETECTING THE PRESENCE OF FOREIGN BODIES IN TRANSPARENT CDNTAINERS Filed April 3, 1948 2 SHEETS-SHEET 2 Patented Apr. 15, 1952 APPARATUS FOR DETECTING THE PRES- ENCE OF FOREIGN BODIES IN TRANS-- PARENT CONTAINERS Paul M. Johnson, Evanston, and Lansing M.

Hinrichs, Wilmette, Ill., assignors, by direct and mesne assignments, to Watson D. Harbaugh, Evanston, 111.

Application April 3, 1948, Serial No. 18,818

The present invention relates generally to apparatus for detecting the presence of foreign bodies in transparent containers and more particularly' to the detection of foreign bodies in beverage bottles.

Beverage bottles are generally made of a transparentg-lass, although other plastics have come into use. in recent years as a substitute icr glass. Frequently, these bottles are provided with irreg- 6 Claims. (Cl. 88--14) absorption as the material of the bottle or to employ mono-chromatic light or other rays of undulating energy and a water-white solution to accomplish a similar result.

A further object. is to mask the bottle with a medium having the same index refraction and approximately the same transmissivity for rays of a particular wave length as the material of the bottle and. testing the medium and bottle for ular contours or embossed designs on their outer 1 the presence of o e n bodies y pa said surfaces to achieve a distinctive appearance or ray therethrough and detecting any variations in greater strength. Other bottles have markings said ray from a predetermined norm either by or permanent. labels which may be printed, y r r il resp e device painted, or glued thereon. Although the inven- A further object is to inspect bottles in a liquid tion is described herein as applied to the dete l5 maintained at a low temperature which aids in tion of foreign bodies in beverage bottles, it is the inspection process by virtue of the fact that not 8.0: limited, and its principles may be emthe refractive index of a liquid is higher at low plcyed to detect the presence of foreign bodies in temperatures and also aids in the bottlin Process other types of transparent containers, wherever where carbo a d e a s a e bottled by p high standards of cleanliness must. be kept. cooling the bottles. just prior to filling so that a One object of this invention is to provide a higher degree Ofearbonation y be achievedsimple and effective method and apparatus for Other additional objects and'advantagesof the automatically inspecting either plain bottles, em.- invention will present themselves to those familbossed bottles, or bottles having permanent labels iar with the a t 01 read the following p flthereon for foreign bodies contained therein, cation in conjunction with the drawings and the preferably justbefore bottling, and for rejecting appended claims. bottles which are not found to be clean. In the drawings:

The earlier automatic devices have been unable Fig. 1 is a vertical section showing t preferred to operate to fine enough limits to detect minute embodiment of the pp of this inventionforeign bodies such. as dirt particles or insects g Fig. 2 is an enlarg p View h i a D because of the tolerances that-have to be allowed the bottle conveying and TeJectm-g mach because of the optical non-uniformity of indiviclamsmual'beverage bottles- Consequently, afurther 013- For purposes of illustmimfg the mventlon, but ject of this. invention is provide an arrange, not in limitation thereof, It is preferred to wash v whereby. the irregular contours of the bottles to be filled m the convent onal manner bottles arising either from manufacturing irregu including h use of brushes a en splfay larities or embossing are obviated during the inthemand P m to a rinsing bath. in which spection they are submerged Wlllh their necks up. The

Another object of this invention is to eliminate bath fills the bottles and the b s are then the inspection errors resulting from drops of 40' moved mm a chamber from Whlch read-y acces rinsing'solution clinging to the bottles byinspectremoved- In chamber bath constl ing the bottles while submerged in. the rinsing tutes a medium which has subsiaptlally S solution and also to thereby eliminate discrep index of refraction as the material of which the ancies arising due. to. irregularities in bottle conf fi are made Preferably the a trans m missivity to certam rays of undulating energy Another object is to immerse the bottles in a such as night Thls' medium .Wets the exposed liquid having a greater refractive index than air v P through-out and F the t duringinspectionthereof in order to minimize the Vlrtually; mvlsibl? as a Separate 9 mdependent degregof refra tion caused by the glass body which has l1ttle or no refractive or reflective When colored bottles are to be inspected, dii- Q On beam of lightficulty has been incurred because of variations The bottle-in this eonditionis .p b y in. the color of the bottles. Consequently, another by step motio along through the Chamber P object is to eliminate the effect of color by subns. between two pre y Vertically sp c merging the bottle in a fluid medium having subtransparent windows. While present between stantially the same properties of color and light the windows, parallel rays are passed" through eign bodies in the bottle decreases the amount of the ray falling on the detector, foreign bodies are detected and the bottles containing them can be rejected.

The preferred embodiment of the rinsing and inspecting apparatus I is shown in Fig. 1. The apparatus ll] comprises a pair of elevators H and I2, a longitudinal chamber 13 connecting the elevators H and 12, a conveying mechanism in the chamber I3, and the detecting apparatus l5 which inspects the bottles as they pass through the chamber I3. The apparatus I0 is filled with the rinsing liquid whose top surface is indicated at l6.

The elevators H and I2 are substantially identical in structure, one being employed to lower bottles I! to the chamber l3 with vibration to jar bubbles loose in the bottles, and the other |2 lifting the bottles I! out of the chamber I3.

In the elevator M an endless belt |8 passes over a pair of pulleys or sprockets 20 and 2!. The pulley 2| is preferablydriven by a motor (not shown) and is synchronized with the rest of the conveying apparatus. The belt l8 carries a number of bottle supporting platforms 22 provided with spring clips 23 whichsecure the bottles thereto. Bottles I! are automatically inserted into the elevator II at the opening 24 from a conventional conveyor (not shown) and held there by the clips 23 in inverted position. The bottles I! are rotated to the upright position as they pass over the top of pulley 2| and then are carried downwardly to the level of the chamber l3 filling with liquid during the latter stages of travel as they drop below the liquid level It. The spring clips 23 serve to prevent the bottles from floating off of the platforms 22 as they descend into the liquid.

When the bottles I! reach the level of the chamber I3 they are pushed off the platforms 22 by a pair of reciprocating finger-like members 26 similar to those shown in Fig. 2. The reciprocating members 26 are synchronized with the drive for the drum 2| so as to push the bottle I! off the platform 22 when the platform is level with the bottom of the chamber [3. Additional members 26 serve to move the bottles through the chamber l3, in a step wise fashion, to the inspection station 2'! and. from the station 2'! to the elevator l2.

As they leave the chamber l3, the bottles I! are lifted upwardly, by the elevator l2, being rotated as they pass over the top of the pulley to the inverted position. Clips 3| similar to the clips '23 in the elevator hold the bottles to the platforms 28 until they pass over the top of the pulley 30 and are pulled off of the elevator by the action of a pair of rods 33. After leaving the elevator l2, the bottles I! slide down the rods 33 into a moving conveyor 34. The conveyor 34 carries the bottles I! in the inverted position to the filling and capping machine (not shown). Liquid draining out of the bottles I1 is collected in 'a trough 35 and flows back into the apparatus proper.

Those portions of the apparatus In through which the bottles I! pass including the conveyor 34 to the filling machine are enclosed in a dirtproof housing 36. Thus it is insured that a bottle I! having passed inspection will not be contaminated during its journey from the inspection station 2'! to the filling machine.

The entrance of foreign particles into the bot- .tle after inspection is also discouraged by the fact that the bottles are conveyed in the inverted position from the point of emptying until just prior to, filling.

In the event that a liquid which must be completely removed from the bottles I! prior to filling is employed in the apparatus l0, additional rinsing nozzles 3! may be employed to give the bottles a rinse of pure water during the time they are in the conveyor 34.

In order to prevent the growth of bacteria, molds, etc., in the liquid, it has been found desirable to provide germicidal lamps such as that shown at 38 within the chamber I3.

In the preferred embodiment a refrigerating coil 39 is employed within the chamber |3 to chill the liquid to a low temperature in order to increase the refractive index and to precool the bottles By precooling the bottles a higher degree of carbonation may be achieved if carbonated beverages are to be bottled. Furthermore, germs or bacteria are less likely to grow in cold liquids than warm.

During the time when the bottles I! are being inspected it is necessary that the bottle |'!a undergoing inspection be accurately located with respect to the detection apparatus l5. To accomplish this, a pair of specially shaped wheels 40 and 4| is provided. These wheels 40 and 4| are substantially identical, being mirror images of one another, and each is provided with four recesses 42 in which the bottles H are received. The star wheels 40 and 4| are driven in a stepwise fashion, a quarter revolution at a step by the action of a Geneva type drive. The drive comprises a shaft 43 driven at a, constant speed and synchronized with the pulleys 2| and 30. A plate 44 attached to this shaft carries an upright pin 45. A driven member in the form of a slotted plate'46 is mounted on another shaft 4'! which extends to the star wheel 4|.

As the pin'45 enters one of the slots 48 it causes the member46 to be rotated through a quarter revolution and then leave the slot 48. The member 46 remaining stationary during theother three-quarters of each revolution of the member 44. The star wheel 40 is also driven from the shaft4'! through alpair of spur gears 50 and 5|.

Thus the star wheels 40 and 4| are drivenin one-quarter revolution steps to convey a bottle I! into the inspection station 2'! and then re-' main stationary for a period of time three times aslong as the time they were in motion before again moving a quarter revolution to the bottle I! out of the inspection station 2'! bringing the next bottle I! into the station 2'!. Upon examination of the drawings for Fig. 2, it will be seen that the bottle Ila undergoing inspection is completely surrounded by the recessed portions 42 of the star wheels 4|) and 4|. This serves not only to hold the bottle Ila, but also to prevent the passage'of light rays upwardly except those which pass through the-bottle Ila.

A similartype Geneva type drive synchronized with the elevator pulley drive may be employed to cause reciprocation of the finger-like members 26. In some instances it proved 'de' sirable-to drive the members 26 directly from -the star wheel drive for these members must be synchronized with the star wheels 40' and M.

The detection system l comprises a light source 52 and a photo-electric cell and amplifier unit 53. The light source 52 which is preferably located beneath the chamber I3 consists of a light bulb 54 and a focusing lens 56 which produce a parallel beam of light.

. Where a colorless solution is employed. a filter 51 may be used, to produce monochromatic light of the desired frequency; A glass plate 58. is mounted in the bottom of the chamber l3 and a similar glass plate 60 is mounted in the top of the chamber 13. at the inspection station 21. Thephoto-electric cell and amplifier unit 53 is mounted above the glass window 60.

Where a photo-emissive type cell is employed in the unit 53 it has been found desirable to use. a lens system similar to that used in the light source 52 in order to concentrate the beam of light on the sensitive surface of the photo cell.

In some instances, however, it has proved desirable to employ a photo-cell having a relatively large sensitive surface such as the coppercopper oxide cell or the selenium cell. When this sort of photo-cell is employed it may be cateddirectly above window 60 and no lens system is required. I

The amplifier relay unit used with" the cell is conventional, it being adapted to. energize a reject solenoid "(not shown) in the event that less than a predetermined minimum amount of light falls on the cell.

The reject solenoid (not shown) is connected through a link 6| (Fig. 2) to a reject cam lever 52. This lever 62 is mounted on a pivot 63 so as to swing to either of the two positions shown. When the lever 62 is in the position shown by solid lines, bottles l'l emerging from the inspection station 2'! pass on through the apparatus, but when the lever 62 is in the position shown by broken lines the emerging bottles I? are pushed into a reject chute 65 by the action of the star wheel 4|. Thus the photo-electric cell causes the bottles to be rejected as they leave the inspection station if they contain opaque bodies which decrease the incident light thereon below a predetermined value.

The reject chute 65 extends to another elevator (not shown) which lifts the rejected bottles to a station above the liquid level where they may be inspected visually.

In some instances it has proved desirable to employ a conventional memory device and reject bottles after they have been lifted out of the rinsing solution but prior to their being emptied by the action of the elevator 12.

The choice of the liquid to be used in the apparatus I0 is governed by the type of bottles being inspected and the degree of fineness of inspection required.

In most instances it is preferred to employ pure water because of its cheapness and the fact that the bottles need not be re-rinsed after inspection. However, where the bottles are optically non-uniform one with another or when greater accuracy is required, liquids having an amount of refraction caused by glass in. water is far less than that caused by glass in air- Furthermore, the closer the index of the. surrounding medium is to that of the glass the less refraction will occur, no refraction at all occurring when the two are equal.

Where the glass of the bottles to be inspected has arelatively high factor of absorption it has been found advantageous to employ a fluid medium having substantially the same absorption characteristics. If the glass is colored, a colored medium may be used or as has been. stated a filter may be employed to produce monochromatic light. of a wave length which is least affected by the color of the glass.

If the apparatus of this invention is to be used .toinspect optically different types of bottles, it

has been found desirable to employ two photoj cells and a pair of light sources, one cell being used for inspecting and the other for a standard. The second cell is mounted opposite the second light source. and a clean sample bottle corresponding to the batch that is to. be run is inserted.

at least 1.333 contained in the tank, a pair of index of refraction closer to that of the bottle glass may be required.

The index of refraction of air is substantially Since the degree of refraction of a ray passing from one medium to another depends on the difference between the f indices of the two media. it is obvious that the transparent windows in the walls of the tank, means for conveying bottles one by one between said windows, a photoelectric cell adjacent one of said windows, a source of undulating energy adjacent the other of said windows, and means for focusing a beam of said energy through the bottles as they pass by and upon said cell.

2. A bottle inspecting apparatus comprising a tank, a liquid having an index of refraction of at least 1.333 contained in the tank, a pair of transparent windows in the walls of the tank, means for conveying bottles one by one between said windows while submerged, a photoelectric cell adjacent one of said windows, a source of undulating energy adjacent the other of said windows, a lens adjacent said source of energy for forming a beam focused on said cell and passing through the bottle disposed between said windows and the surrounding liquid.

3. A bottle inspecting apparatus comprising a tank, a window in a wall of said tank, means for locating individual bottles adjacent to said window, means for forming a beam of undulating energy and directing same through said bottles as they are located adjacent to said window, a fluid medium in said tank having an index of refraction close to that of the bottles for reducing the refraction of said beam of energy as it passes through said bottles and a photoelectric 1 cell for measuring changes in the intensity of said beam, said cell being disposed proximate to said window.

4. A bottle inspecting apparatus comprising a tank, a body of liquid having an index of refraction of at least 1.333 in said tank, means for conveying bottles through said tank beneath the surface of said body of liquid, means for forming a beam of light beneath the surface of the liquid,

and a photoelectric cell disposed in the path of the beam of light for measuring the intensity thereof, said beam forming means and said photoelectric cell being so arranged with respect to the conveying means that said bottles pass through saidbeam on being conveyed through said tank. W

5. A bottle'inspecting apparatus comprising a tank, a body of liquid in said tank having an index of refraction of at least 1.333, means for forming abeam of light beneath the surface of the liquid, a .photo tube disposed in the path of the beam of light for measuring the intensity thereof, and means for conveying bottles through said tank beneath the surface of said body of liquid and through said beam of light.

6. A bottle inspecting apparatus comprising a tank, a quantity'of liquid disposed within said tank, said liquid having an index of refraction relatively close to that of bottle glass, a photoelectric device disposed adjacent to a wall of said tank, means for conveying bottles through said tank beneath the normal level of liquid, and means for forming and focusing a beam of light through the liquid and through a bottle undergoing inspection and upon said photoelectric device.

PAUL M. JOHNSON. LANSING M. HINRIC'HS.

REFERENCES CITED file of this patent:

UNITED STATES PATENTS Number Name Date 855,402 Hayden May 28, 1907 1,305,032 Trent May 27, 1919 1,381,325 Meyer June 14, 1921 1,433,284 Johnson et al. Oct. 24, 1922 1,908,610 Jones et al May 9, 1933 2,124,423 Ladewig et al. July 19, 1938 2,137,187 Stoate Nov. 15, 1938 2,196,389 Fogg et al Apr. 9, 1940 2,253,581 Reynolds Aug. 26, 1941 2,265,037 Gulliksen Dec. 2, 1941 2,286,836 Sachtleben June 16, 1942 2,295,366 Stout Sept. 8, 1942 2,296,027 Gettelman Sept. 15, 1942 2,333,791 Hutchinson Nov. 9, 1943 2,431,519 Stoate Nov. 25, 1947 FOREIGN PATENTS Number Country Date 592,529 France May 1, 1925 OTHER REFERENCES 0 Document 2037, pages 200 to 204, Publication Government Printing Oflice. 7.)

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