Patent GB-512564-A (GB)
Title: Improvements in and relating to the testing and sorting of eggs
IPC: G01N33/08
Filed: 1938-02-05
Abstract: 512,564. Testing eggs. RIVENBURGH, F. L. Feb. 5, 1938, No. 3683. [Class 37] Eggs are tested with respect to their lifeactivity by measuring the inherent e.m.f. between spaced points of the shell. The shell resistance may be reduced or eliminated at the testing points, and the eggs may be automatically sorted according to their e.m.f.'s. Before testing, the eggs are aroused by heating them to incubation temperature for a certain period, when it is found that if all the eggs have been similarly heated an inherent e.m.f. exists across a minor axis thereof, this e.m.f. being different for fertile, sterile, and dead or dying eggs, and depending in value and in direction on the degree and duration of the heating. As sterile eggs give the smallest e.m.f. they are preferably first sorted, after which the dead or dying eggs may be sorted from the fertile eggs which produce a smaller e.m.f. than the dead or dying eggs. After heat treatment the eggs are fed down a guide 36 onto an insulating conveyer belt CB where they rest in apertures 33 and are prevented from rolling movement by pairs of pins 35, which project through the belt and form teeth 35b for engagement with recesses in the driving drum 29, Fig. 3. The eggs first pass a plurality of wetting structures WS which wet the upper and lower sides of each egg with a conducting solution to reduce the electrical resistance thereof, they are then tested at TS, the wetting solution is removed at the cleaning structure CS, and the eggs are then guided by the pins 35 and walls 80 around the drum 29 where they are automatically sorted according to the test, one group e.g. the fertile egg group, passing through a flap 82 down a guide 81 over an ink pad 201 which prints appropriate data on each egg, while the eggs of the other group pass around drum 29 to a guide channel 88. Testing, wetting, and cleaning apparatus. The test structure TS comprises two insulated tubes 44, Fig. 6, each containing an electrode 101 immersed in electrolyte, adapted to contact with the egg through a porous wick 45 secured in the end of the tube. The tubes 44 are secured to holders 43 and moved towards each other intermittently, by a spring 48 connecting parallel motion links 41, 42, under the control of a cam 52 on a power shaft 21, which also intermittently drives the conveyer drum 29 through a ratchet 28, and cam mechanism, so arranged that the drum and conveyer are advanced only when the two wicks 45 have been withdrawn from an egg. The lower wick 45 preferably just lifts the egg off the belt CB at each lifting to ensure a good contact. The porous wicks are of electrically neutral material, and, identical electrodes are used, e.g. silver chloride with an electrolyte of calcium chloride solution. The electrolyte is fed to the tubes 44 from reservoirs 96, 97 which together with the supply tubes 47 are insulated from each other. The wetting and cleaning structures WS, CS are identical in construction with the test structure except that the electrodes are omitted, and the wicks of WS, TS, CS, are reciprocated in synchronism. The wetting structures may be connected to a common reservoir 95 and the cleaning structure is connected to a vacuum pump instead of a reservoir. Testing procedure. To standardize the electrical test circuit Fig. 1, with switches 103, 155 open, switches 111, 117, 126, 146 are closed by knob SW. The amplifying push-pull connected valves VT<1>, VT<2> are then brought to the balance by adjusting rheostat 118. The ammeter MA then indicates zero. Its sensitivity may be varied by a rheostat 130 and its range altered by using different shunt resistors 127 controlled by a switch 128. Stray potentials in the test electrode circuit are then balanced out by short-circuiting the electrodes TS and adjusting switch 103 and potentiometer 107 until meter MA again reads zero. With the test electrodes apart a standard voltage derived from a battery 153 and variable resistances 151, 152 and equal to that of a fertile egg, is then applied, by closing switch 155, across the grid-cathode resistance 108a of valve VT<1>. The balance is upset and ammeter MA deflected. Swich 125 is now moved so that the anode current of the amplifier VT<3> flows through a relay MR instead of the meter MA. The sensitivity of the relay is then adjusted by resistance 130a so that the relay just operates with this standard current. Switch 155 is then opened and the apparatus is then set into operation by rotating the power shaft to advance the conveyer and reciprocate the structures WS, TS, CS. As each egg is tested the inherent e.m.f. thereof is applied across the grid-cathode resistance 108a and the relay MR is actuated only if this e.m.f. is equal to or greater than, the standard e.m.f. Sterile eggs will therefore fail to actuate the relay and are thereby sorted as follows. Sorting mechanism. A switch 55, Fig. 6, is closed by the cam 52 during each testing operation and, if the relay MR is not operated, egg sterile energizes over the normally closed contacts thereof, a solenoid 77, Fig. 3. The plunger 76 thereof rocks a bell-crank lever 74, pivoted on the drum 29, in opposition to a spring 75, permitting a pin 70, Fig. 8, to be projected through the drum by a spring 73 to the dotted position. On further rotation of the drum 29, the sterile egg eventually comes opposite the door 82 just as the corresponding projecting pin 70 comes opposite a pivotal lever 85 which it rocks in opposition to a spring to lock the door 82. The sterile egg therefore passes further around the drum 29 into the guide 88 and the pin 70 is reset by a ramp 89 and held in this position, shown in full lines, Fig. 8, by the corresponding spring biased lever 74. Eggs in which the inherent e.m.f. is greater than the standard, operate the relay MR when tested, so that the solenoid 77 is not energized, the corresponding pin 70 is not projected, and the egg, when it reaches the door 82, rolls therethrough under gravity since the door locking lever 85 is not actuated. A counter RC, Fig. 3, operated through an arm oscillated by the solenoid plunger 76 registers the number of sterile eggs while a counter 120, Fig. 2, operated by a spring arm raised by each egg as it passes registers the number of eggs tested. Modification. The test electrode wicks 5 may be replaced by very fine needle electrodes, e.g., of silver or platinum iridium, which penetrate the egg under test to a depth of @1/32 in. Specification 479,022 is referred to.