DE2659461A1 - DEVICE FOR AUTOMATIC CHECKING AND SORTING OF NUCLEAR FUEL TABLETS - Google Patents

Description

PATENT ADVOCATE

DIPL. ING. K. HOLZEK

PHIIiIPPINE-WEtSEB-STRASSK 14

8900 AUGSBURG

TBLEFOK51β47δ TELEX 533 SOZ FS * « ^{1 d}

f. 836

Augsburg, December 23, 1976

Westinghouse Electric Corporation, Westinghouse Building, Gateway Center, Pittsburgh, Pennsylvania 15222,

V.St, A,

Device for the automatic testing and sorting of nuclear fuel pellets

The invention relates to a device for the automatic testing and sorting of nuclear fuel tablets, with a conveyor chute feeding the tablets and a

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move the tablets in a straight line through the testing device Feed mechanism, further with an optical probe to check the tablets for surface defects, which is a light source that traverses a light beam onto the testing device Tablets aligns, and a receiving device that receives the light reflected from the tablet as well a converter for converting the received light into an electrical signal, further comprising an electrical one Circuit that determines whether the electrical signal indicates a surface defect or whether it is above a predeterminable reference value, which corresponds to a perfect tablet surface, and with one controlled by the output signal of the circuit Device for sorting out defective tablets «

To generate the thermal energy in a nuclear reactor, fuel tablets enriched with uranium, each about 1.5 cm long and 1 cm in diameter, are filled in long cylindrical fuel rod casings that are located in the reactor pressure vessel ₉

During production, these fuel tablets are subject to pressing and sintering processes, so that a more fragile ceramic tablet body is created “After that,

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Each tablet is ground to the exact size of the knife, which is slightly smaller than the inside knife of the separating rod sleeve, so that a single tablet can easily be inserted into the sleeve; fill in and on the other hand a bestnüglichr vür-neüber ^ ang zv.-ischen the tablets and the r: ü 1 Ir ο hrwcU'dun gen takes place, χα process of the production know an aeti labie'cten C surface defects in the form of LC- stone una bit. Since for reasons of economy IASS & nfertijun ^ aer i'abletten notuendi ^, ^r v ei'den the ^r Jabletteti außerueü üiit high speed transported through the manufacturing equipment, by aie grinding device, which is why due aer ^ .erühruiujen s ^T;. Iscncn acn individual tablets and other, abrasion verursaciienden: ^.ri: ften more Oberf enler lächeiif ^ us in the form of bridge in the cylindrical Taclettenoterf li'che ent are the total shortage of kerar.ischeia Tablettenaaterial _a V.'enn caused by surface defects and in Ausbri'cne The large number of tablets are due to exceed a certain number of tablets, so that the reactor output is adversely affected, since distortions in the output distribution can occur or the reactor output does not reach its maximum value "

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To ensure that the L-fuel tablets used in the reactor meet the rlons trukt ion sbedin.iun ^ en, the tablets are checked according to Leendi .'- jUn ^ des ocnleifvor ■> ;: _. An r, s before they are poured into the fuel rod cover, the test includes a visual inspection of the tablets lying in parallel lending and the comparison with a tablet erinorrna I ₀ Since the optimal reactor performance is also based on the fact that fuel tablets ν er v / ends, their weight and Forin stiiiuaen exactly, the testing personnel is often all too careful and una sorted tablets, which are in themselves completely perfect for use in the reactor _o This practice naturally leads to high production costs, since the sorted tablets first have to be crushed to powder again before the material can be used vi can be used again for tablet production.

; is already mechanical and pneumatic as well Laser beam and other electronic devices have been proposed to scan the tablets for surface imperfections to be able to examine which exceed a certain predetermined tolerance.

In a pneumatic system, a number of air nozzles are placed on the tablet to be examined.

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aligned and the pressure feedback is used for the detection of surface defects, wherein the tablet either fixed or moving * The Li'achteil of this method is that it is slow in view of the large number within a certain time period to be tested tablets. An arrangement of several pneumatic elements, however, requires that the tablet flow is divided between the various measuring points, which in turn requires precise control of the air pressures and the mechanically operating parts of the system.

Mechanical measuring or surface testing devices such as dial gauges, profile measuring devices and electronic measuring gauges with linearly variable differential converters or similar components require mechanical contact with the fuel pellets, which results in lengthy streams and low measuring performance, since each individual fuel pellet has to be scanned mechanically by the measuring device. In this type of measuring several measuring points are required for an acceptable production output can be managed, what truktionen complicated Cons and questionable reliability entails ,,

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In laser and other electronic measurement systems is a single laser beam device application in order to investigate the tablet surface for errors by which is sampled from the tablet surface reflected light from two different directions and is converted into analog output signals "A transducer circuit direct display then allows the Pehlergrößen _o A laser beam device works quickly and precisely, but it is necessary to use an extensive and complicated scanning device to cover the entire tablet surface, since the angle at which the scanning beam hits the tablet is constantly changing «

The invention is based on the object of a working according to the principle of optical surface scanning Tablet testing device for measuring surface defects in such a way that they are simple, reliable and works quickly and automatically rejects the tablets that do not meet the specified quality standard »

To solve this problem, a device of the type mentioned according to the invention is thereby

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indicates, oaf. the ortische .probe and iLrt /'.ufnal^ieeinrichtung adjustable, but fixed to the l'atlettenvorschubv / ej an.3e0rc.net are uria there ?; the "feeding device; for rotating the tablets. v. ^r ä /; rena αεε passing the local table;

An embodiment of the invention is described below with reference to the attached drawings In the drawings lines:

1 is a scientific representation of an automatic tablet testing and sorting device
according to the invention,

2 a view of the tablet testing and sorting device,

3 is a side view of the in Fi ^ ₀

i ^ th establishment,

Fi ^ ₀ ^ a plan view of the in

Fig, 2 device shown,

Fig. 5 is a view showing details

view of the feed mechanism

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the testing and sorting facility,

a side view of the in FIG i ^ th feed mechanism,

a section along the line VII-VII in Fig. 5 »

the micrometrically adjustable holder of the optical probe the testing and sorting facility,

a view of the sorting device of the testing and sorting device,

IC is a side view of the FIG

device shown, and

an error-time integration and

Sorting circuit for storing surface defects representing Information and with a time delay for sorting out not flawless tablets.

8 27/0976

During production, the green, enriched uranium-containing fuel tablets are subjected to a prepi and sintering phase, which occasionally results in tablets with a diameter outside the permissible tolerance range, so that tablets with a uniform diameter are produced, all tablets go through a grinding device in which oversized tablets are ground to the permissible size, while the tablets lying within the permissible tolerances pass through the grinding device without being affected by the grinding wheels _Q

The fuel tablets are then one at a time pushed between two rotating rollers 20 and 22 (Pig, I) and moved in a straight line along the roller pair, each tablet for holes, cracks, breakouts by means of a distance-measuring optical probe 24 and other surface defects are scanned, which reduce the amount of tablet material «,

E-ine power supply and transducer circuit 2b modifies what is received again by the optical probe Light into electrical analog output signals that a Pehler-Zeit-Integration- and tablet sorting circuit 28 are supplied, Sin fiber optic tactile

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265346

head 30 and. a photocell sampling switch 32 keys the position of each tablet on the rollers 20 and 22, and control the integration and sorting circuit 28 _O As will still be described in more detail, this circuit 28 serves to determine whether an unacceptably large amount of material in the tablet surface absent, and, if this is the case, this circuit actuates a sorting magnet, eier separated the tablet in question after leaving the rotating rollers 20 and 22. The tablets lying within the permissible tolerances are moved on to a filling station 36, where they are filled into fuel rod cladding tubes .

Figures _0, 2, 3 and 4 show the tablet testing and sorting device in more detail. This device comprises a frame 36 which carries a V-shaped tablet feed chute 38 mounted on a vibrator, a bracket 42 and rubber buffers 44 keep the vibrator 40 and the tablet feed chute 38 inclined at an angle with respect to the horizontal. The vibrator 40 is used to convey the fuel pellets from the grinding device via the feed chute to the test zone, where they are tested.

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speaking vibration frequency in r, cnwin. '; uii ._; en "lrä" u is the vibrator 40 at he a - ^v ii trieur, he 45, a number of flexible flatteners 46 and an i.altev / intcei 46 which is screwed to the loden at the bottom of the channel 3b by means of screws 50, connected to the feed channel, so that tablet particles that have broken out of the tablets are removed from the feed channel before each cadet reaches the rollers 20 and 22, is at the bottom of the feed channel ~ jo an opening is provided which is smaller than a normal tablet ₀ tablet fragments fall through this opening onto a chute 52, via which they reach a collecting container

From the feed channel 3ß the tablets reach actual testing device 54, where they are examined for surface defects and then sorted accordingly, As shown in Figures 2 to 7, the test device has two spaced apart!. * " U-shaped supports 5c and 58uf mounted on frame 36 sindo On the supports 56 and 58 there are plates öü and 62, each of which has an approximately triangular opening 64. Two rollers 66 and 68 are each with their two ends in, in the plates 60 and 62 arranged bearings and have one only great distance between them so that they

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wear material tablets, while a straight line, d _o h _o in the Fir; ο 2 and 5 moved through the testing device from left to right weraen _e The two rollers and 63 v / ground by a synchronous motor 70 is driven, with a gear 62 with two output shafts 74 -Secu! .pelt, soft the latter are connected to a roller each. Both rollers 66 and 68 thus rotate i:> it the same speed and ira same direction, "Since the '<\ o tor and from The gear expediently under the Zafünrrihrie ^3'-1 to-jeoranet Vierden, the two Abtriei; ^r i: ;; lle: i 7 '+, j- ^ vrils' But universal joints 45 with the l · ■ - ■ ": -"".. ■ - '. ■■■ - ■ wind α-ΐ :;' ..El7.on connected ,,

'ei 7.ir' .- / e :: - ^jua_; ; oi. "al-.ien with a diameter of l _s o er :; uri ..: elneni /,.",ivii-iahlenverhärtnis in the gear of 7J; \ 65 ureiien iio to tablets with a through -'- "lesser of about 1 er: -Tilt a speed of II85 U / min, v / hen the tiio Jrehzanl. IOT or wave I8OO U / min"

the vibrating feed channel 38 conveys the tablets to the testing device nin, the foremost tablet is pushed under a hold-down spring 75 on to support pad 76 into a position from which this tablet can be moved in a straight line along the two rollers 66 and 68 »

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The corset holding spring is intended to cause the tablet to jump during the transition from the feed channel 38 to the circumferential one Prevent rolling "

As shown in FIGS. 2 to 7, the feed mechanism moving the tablets forwards along the two rollers has a chain drive attached to both U-shaped, upwardly projecting supports 56 and 58. Each of the supports 56 and 58 carries a shaft 78 (Pig, 5 to 7) which are axially fixed by cold rings 80. On each 'shaft 78 there is a sprocket 82 which has outwardly protruding teeth 83 which cooperate with an endless roller chain 84 which is formed from a row from there to the interconnected joints "to drive the roller chain on the sprockets 82 serves a state shown in Figo 3 synchronous motor 86 which is disposed on one side of the feed mechanism una the output shaft via a slip clutch 88, Sl, a projection 90 of a shaft 78 acted This moves the roller chain at a constant speed «

Around the tablets at a constant feed rate To move through the test zone, roller chain 84 is a number of outwardly protruding drivers 92 provided, which by means of a slip

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binding 94 are attached to the chain _o While the chain moves over the front sprocket 82, the drivers 92 describe a corresponding loop around the sprocket, before they move in a straight line along the two revolving rollers 20 and 22 in the section between the two chain wheels veiterbewegerio At the upper end of this curve, a WoIframcarbidkugel 96, which is welded at the end of the upward between the two rollers protruding driver, the rear end face of a tablet in its axis of rotation and pushes this tablet at the speed of movement of the chain corresponding to the feed speed along the rollers Next ,, the moving chain thus pushes via the driver 92, the tablet through the inspection zone through, where it is checked for surface defects _o país should become jammed a tablet for any reason in the feed mechanism, so the driver puts due to the slip coupling 94 in a horizontal position for ück, so that the force is reduced which is otherwise exerted on the parts of this mechanism by a tablet jammed in the feed mechanism, _etc.

The size of surface flaws and diameter deviations for each fuel pellet automatically

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and being able to measure quickly is a careful one Coordination of the mechanical and optical-electronic components of the equipment necessary to ensure, among other things, that the required functions are within the Skills of each component remain, V.'you practice explained The mechanical components are used to feed the fuel tablets onto the rotating ones h'alzen, polygamy the tablets at a certain speed in Offset rotation. In order to roll each tablet lengthways and through the zone, in v / elcher die Tablet optically scanned for surface defects Y / ird, there are small tungsten carbide balls on the drivers attached, one tablet at a time and there is only a slight influence on the outside world Ta, twisting motion of the tablet while passing through the Effect scan zone ,,

The tablets are scanned for defects with the aid of a commercially available distance measuring optical probe 24 and a power supply and transducer circuit 2G _{0 associated} therewith. Such an optical probe is described in US Pat. No. 3,788,711.

This optical probe 24 has a fiber optic Head with a lens system that can be used both for project

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tion of a light beam on the '. Tablet surface al ;; also for the -ümpfa:] ^ of the light reflected from the tablet surface serves ", The reflected light is converted into electrical signals in the moon 2k and the ^ switching ^ 25 produces an analogue ^ output, which the LoriikuCiialtunysanorunun ^ the error-time integration and positioning circuit 2 0 is supplied. This circuit differentiates between acceptable and unacceptable fuel tablets and controls a sorting machine, which sorts out the unacceptable tablets.

The optical probe 2k is arranged above the rollers 20 and 22 on a bracket 108 in such a way that it directs a beam of light onto the rotating tablet transported by a driver 92 along the rollers 20 and 22. The sonar head has an iienn distance of about 1 _a 2 ^ cm from the tablet surface to «To enable adaptation to different tablet diameters, the probe head can be adjusted on a micrometer slide 109 (Fig. 8). A hand crank 110 is used for adjustment.

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BATH ORIGINAL

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It has been shown that errors in the tablet surface with a depth of less than 0 _o 063 now are insignificant because the shortage of the tablet material has no substantial influence on the reactor power in such an outbreak depth of ₀ to the detection of break-out or error depths of more than 0.063 min, the probe head is set to a position value of + 0.14 mm with reference to a flawless tablet surface by means of the micrometer slide, which results in a reading that is normally 0.063 mm above the error detection level of 0.075 mm, which in the error time -Integration and sorting circuit 28 is set electronically _o

It is clear that the optical probe must only start scanning the tablet surface when the front edge of the tablet in question comes into the area of the light beam emanating from the probe head, “Da the probe and its associated circuitry are not reflective between one tablet and another Can differentiate area, it is necessary that the circuit 28 assigned to the probe only then error-indicating Can receive signals when a tablet actually moves under the probe head Switching during the correct time in each case

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To set activity, numerous different arrangements or methods can be used _o In the embodiment chosen here, a fiber optic probe head JO with a lens and a photocell scanning switch 32 with a photocell and an amplifier are provided to light reflected from a reflector 104 in a to convert the amplified signal which is fed to the integration and sorting circuit shown in detail in FIG.

Reference is made in particular to FIGS. 2 to 4 and 11 below. The fiber optic probe head 30 is on one on the platen. 62 mounted holder mounted 100 and so oriented that it is directed via light transmitting fibers a light beam directly on the tablet surface and of the tablet surface reflected light on this receiving fibers back passes _o The fiber optic probe and its associated photocell are designed so they -that the Activate optical probe 24 in the event of a reduction in the amount of light returned to the photocell and consequently in the photocell output voltage

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709827/0976

On the probe head, the back light generated a relatively high photocell voltage when a tablet moving forward was exposed to the sun; Probe eurücV.jev: orfenen light beam interrupts, 1: 0 causes the strong waste α er ~ "hetoaellen;iusr;ari; / Fi: i anr; un, _; cu..y address a? I-lelais, which the" eriler-iJeit-Inte ^ .riLCi & nt.-schaltunr in! '"ti-jk ^ it sets how nachrtfcoenu i.oca anh & r.d eier ? ir _a 11 rnerir in. individual descried v; ird.

ie optical üonde 24 v; eist on ebenfallo ^ inen fay eroptischen c-ondenkopf, the vorzu; isv ^r eiae sv / Ei having Orurpen of light-conducting fibers, of which a group to Lieh ta us consignments ^ and one group of:.; Licnteiiipfun ^ serves ο uie optical probe works aiit iiiife the li entinenge, which reflects from images projected on the surface of the respective tested fuel tablet and lying out of focus varcu The entire scan image projected onto the tablet surface is a width of about 0.75 mm on. According to the aforementioned US Pat. No. 3,788,711, a lens system is used to project light images onto the fuel pellet, and the image size, shape and light intensity are appropriately set to optimize linearity, measuring range and sensitivity the photos on the tablet

BATH 709827/0976

If the fuel pellet moves relative to the probe and the emitted light hits an eruption or another surface defect, the light reflected to the light-receiving fibers has different levels of light intensities that are implemented in the circuit 26 corresponding to different voltage levels _0, the output voltage is an analog signal, which represented the distance between your probe head and the tablet surface

The synchronous motor 70 drives the two rollers 20 and 22 at constant speed and the roller chain is also moved at constant speed. When a driver 92 moves a rapidly rotating tablet to the scan area of the fiber optic scan head 30 moves, light is first reflected by the reflector 104 »The output voltage of the The photocell of the photocell scanning switch 32 is fed to a comparator 116 according to Pig «11» this voltage is compared with a reference voltage generated by a voltage divider. It is the photocell output voltage greater than the equivalent voltage, so

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is aas potential at the comparator output and at the control input an electronic switch 116 high so that the switch is conductive and a capacitor 120 with pale connects »The high potential keeps the switch in the conductive state, so that the charging voltage of the capacitor 120 July stays.

If the person in question 92 pushes the tablet in question under the light beam that is exhausted by the fiber-optic scanning head 30, the light beam reflected by the reflector 104 is cut off, as a result of which the Pbotocell output voltage drops and the switch goes into the non-conductive state, whereby the capacitor 120 of Ground separated x ^ ird _o This enables the circuit shown in FIG. 11 to process an analog signal received by the circuit 26 _o

The precise position of the fiber optic scanning head 30 with respect to the optical probe 2H is chosen so that when a tablet moving under the fiber optic scanning head causes the voltage reduction to render the switch 11S non-conductive, the leading edge of the light spot produced by the optical probe is completely on the tablet surface, O ₃ 37 mm inward

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of the tablets leading edge ₀ Thus, the nOglichkeit is avoided that the error-time integrator circuit integrates 28 excessively large signals _Q Since the fuel pellet is moved forward by the driver 92 while rotating at the same time, the optical probe scans a helical track init a Width of about 0.75 mra on the tablet surface, and as long as there are no depressions such as cracks or other defects in the tablet surface, the light reflected back to the optical probe does not change significantly, but if a broken area or other defect is detected , the plane of the light spot projected by the optical probe 24 onto the tablet surface is shifted and there is a corresponding decrease in the analog voltage signal which is fed to the error-time integration and sorting circuit 28 ₀ This voltage is fed to an amplifier 122 working as an impedance converter The output signal of which is fed to a comparator 124, which compares it with a reference voltage generated by a voltage divider 126.

The reference voltage generated at the voltage divider is set slightly below the voltage value which is found when scanning a flawless tablet surface

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The optical signal 24 results in _o If there is a depression in the surface of the tray with a sufficiently great depth, the sonar output voltage is less than the reference voltage biasing the controller 124, so that ¹ ? the potential ai; i comparator output to a high value jumps _o IIIn switch 12ο then connects the positive Speisespannurigsansculuß via a resistor 129 NIIT the .Kondensator 120 so that it is charged to a value corresponding to the ^Fli: cne of the determined at the fuel pellet recess corresponds ο During the further scanning As the tablet rotates and moves forward along the salt through the optical probe 24, any errors detected in the tablet surface are converted into signals which are integrated by the capacitor 120 «

A voltage divider 130 generates a reference voltage for a comparator 132 _O. As long as the charging voltage of the capacitor 120 does not exceed the reference voltage value generated by the voltage divider 130, the output of the comparator 132 does not change its state, so that the tablet in question is viewed as faultless and transported onwards without hindrance.

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If the charging voltage of the capacitor 120 exceeds the Ivert of the reference voltage generated at the voltage divider 130, nu. ^p . The tablet in question must be separated out. ο When the tensile stress is exceeded by the capacitor charging voltage, the output of the comparator 132 jumps to high potential the time synchronization of the device is maintained.If this tablet leaves the test zone, the fiber optic scanning head 30 detects the end of the tablet, whereby the photo cell output voltage rises, which in turn changes the output of the comparator 116 to high potential and consequently the switch 118 becomes conductive draws ₀ At this moment the capacitor 120 discharges, so that the capacitor voltage is filled below the reference voltage value of the voltage divider 130. This in turn causes the output signal of the comparator 132 to jump back to low potential so that a new sampling cycle can begin »

The mechanism of the device is designed so that the tablet after leaving the test zone until .ir calibration of the 3 or tier channel requires a time of 2 s » This means that the reject signal is delayed by 2 s

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vjerden "iu ^Q ;, before the sorting device may be operated" In addition, every 0.7 3 a new tablet enters the morning ", This means that while one of the sorting lines is delayed, another sorting line is already being carried out can be generated ₀ Therefore, the electronic deferrers ^ ^ to chan sschaltun -;; divided into three sections, each s create a time lag of 0.66, "the United icgerunssschaltun ~ ordered three identical, rapidly regenerating liioncßtabilen flops that? by a Ci. ^ nal setri ^^., changing into negative di cn- tunj , "! -" becomes oath, if there,? The first flip-flop switch 1 ^ 3; whereby the flip-flop 136 jetrig ^ ert v; ith the cozy in the l ^ ^e manner to vieiteren 0.66 s, the circuit 138 tri Gert ^ and schließlicn again after 0.66 s a further monostable multivibrator l4ü triggerto This last monostable l4o has a much shorter time constant than the other x'ippschaltungen and merely determines v / ie the Aussortierrinne lance remains open, darait the auszusortierende tablet falling through ₀ This time is about 50 i.is "

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BATH

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The three regenerating successive serine Il monostables allow the device also responded to successive auszusortierende tablets Each of wionostabilen multivibrators can almost immediately be triggered again after a discharge, which is why a series of pulses with intervals of 0 ₉ 7 s through the 2 -s-delay switch can run through »

When the delayed signal reaches a transistor 166, it becomes conductive and energizes a relay 168, which closes a switch 170 and thereby connects a HO-V voltage source to a rectifier bridge 172 and a counter 174. The rectifier bridge 172 applies a direct current pulse a rotary magnet 176 (Figo 3, 9 and 10), which effects the sorting out of the tablet concerned, and the counter 174 is incremented by one, which indicates that the tablet has been sorted out _o The sorting magnet 176 is mounted on a plate I78, which protrudes from a support I80 fastened to the frame “An arm 182 fastened adjustably to the magnet armature shaft 184 carries a plate I86 which is aligned with the V-shaped tablet transport channel I88 between the test zone and the filling station and which forms part of the tablet transport channel and

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a little more erroneous than a tablet i; "'t, term which gets a lupuls, the plate is lor .. in a clockwise direction:; e pivots through, so that a" jffnun "arises in the transport channel v.'elche auszusortierende the tablet in a coups lu £ fills ^"r fi faultless tablets ice jnal generated in Aussortierst. in eggs logical Scnaltun ^, so dti ^ then the / usscrtiermagnet not excite wirα and these tablets to freely weiterbewe ^ en,

In order to obtain an exact count of all the arrangements to be generated by operating tablets, isb geniäß Fi ^ ₀ 11 a counter connected 190 at 152 between the Avoided 116 and aera electronic switch HS "This counter is responsive to a reduction in the voltage, aie occurs when a tablet is between the reflector and the optical fiber Scan head 3öbevie ^ t ₀

If the vibrator of the tablet feed chute is set too fast or too many tablets are fed v / ground, a ratchet mechanism can be used at the end of the feed chute shortly before the orphans, uiti to separate the tablets from one another before they enter the rollers Moving up a driver triggered so that each

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BATH

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a tablet released v / irJ and can enter the abotanü between two banacnbaren -litnehiiiern, this arrangement negates an appendix "ufuivj of ^r <" aliletton and an otherwise incorrect Ta b 1 e 11 e η suf ϊ? i <;_hru:; .

7 0 9 8 7Λ / J) π 7 6

^{BAD offlQWAL}

Claims (1)

Claims - Device for automatic checking and sorting "" of nuclear fuel tablets, with a conveyor chute feeding the tablets and one with the tablets Feed mechanism moving in a straight line through the testing device, further with an optical probe to check the tablets for surface defects that a light source directing a beam of light onto the tablets passing through the testing device, and one that receives the light reflected from the tablet Recording device and a converter for implementation of the received light into an electrical signal, further comprising an electrical circuit that determines whether the electrical signal has a surface defect indicates or whether it is above a predetermined reference value, that of a perfect tablet surface and with a device for sorting out controlled by the output signal of the circuit flawless tablets, characterized in that the optical probe (2-4) and its receiving device are adjustable, but are firmly arranged on the tablet feed path and that the feed mechanism is a device (20, 22; 66, 68) for turning the tablets while passing - 29 - ORIGINAL INSPECTED 709827/0976 ^OR runs over optical ^ or = · de has, 2, Zinrichtunp. according to ^ nsnruch 1, dadurcu marked, ciaP aie electrical ccrialtunj (2c) a comparator (124) zup comparison oe-3 electrical ö -ignals rr: it is your reference value, further an integrator (ISO) for. Comprising adding up and storing Cberflächenfenler representing difference signals, and a further comparator (132), the ηit the respective stored integrated value of another eezugsvert corresponding to an acceptable tablet for vergleicot: d, if the integrated V.ert aen further Bezugsi \ ^r ert exceeds, sent a sorting signal to the said sorting device 3ο device according to claim 1 or 2, characterized in that that the device for sorting out defective tablets, a part of the tested ones Removable element (166) forming tablets from the transport channel leading away from the testing device and an electrical actuating device (I76), which via an actuating arm (182) with the movable away Element is connected and when the actuator by a reject signal of the electrical Circuit (28) is controlled, the movable element - 30 - 709827 / 097S moved so that the tablet to be sorted out falls out of the transport channel _β 4 _β Device according to one of Claims 1 to 3, characterized in that the device for rotating the tablets has two parallel V; rollers (20, 22; 66, 68) which are arranged at a mutual distance and which take up the tablets between them and in the Rotate the same direction of rotation about their longitudinal axes and that the feed mechanism has spaced apart, sv ^r i see the two rollers projecting drivers (92) which push the individual tablets along the rollers _o 5ο device according to claim 4, characterized in that the feed mechanism has an endless chain (84) which runs over two mutually spaced chain wheels (82) and on which the drivers (92) are arranged _o 6ο device according to claim 5, characterized in that that the drivers (92) are articulated to the chain (82) so that they can be bent and each has a ball at its free end (96), each in the tablet axis attack on a tablet, - 31 709827/0 9 76