Патент USA US2380651код для вставки
July 31» “1945 H. T. JEFFERY` 2,380,651 ' l PNEUMATIC EJEcToR Filed Feb. -11, 194s /99 " /97 _ ¿sheets-sheet 2 5/ 4 \\ \ \ ß.. Í . . l July 31, 1945' . ` H. T. JEFFERY i » 0 TIME _ 2,380,651 PNEUMATIC EJEGTOR ` Filed Feb. 1l, 1945 3 Sheets-Sheet 3 THREE 191 massa/ef sw/rcH .==, ’ - mon/@Hr @-427 . v 91 ¿2 Waver/av udg; a, y I . l Tr ï , R4 ’fag “im «may _ ' y I Lâç ' > 0 H - W [email protected] _ v 2,380,651 Patented July 31, 1945 UNITED ‘STATE S PATENT OFFICE 2,380,651 ,PNEUMATIC EJECTOR Harold T. Jeffery, Wilmette, Ill., assigner to Yeomans, Brothers Company, a corporation of Delaware vApplication February 11, 1943, Serial No. 475,577 2 claims. (ci. 3oz-53) The present invention relates to pneumatic ejectors and is particularly concerned with pneumatic ejectors capable of use in the dis position of packing housewaste and like mate - rials. ' features of the three-way valve which .con stitutes a part of the apparatus of Fig, 1; Fig. 5 is a complete wiring diagram of one embodiment of the ejector control system used of the present invention; and . Fig. '6 is a schematic diagram of the control 4 The satisfactory handling ofpacking house system. waste and similar materials has long presented a serious problem to the conveying art. Be cause of sanitary considerations and because ' » Referring .to Fig. 1, the ejector unit of the embodiment ofthe invention there illustrated comprises a main frame 1 which may conven-> 10 these materials> often include large pieces, suchV iently be fabricated of welded structural ele as parts of the viscera, of animals which may be very tough or veryy sticky, or both, it is not practical to elevate or to move wastes of this type forv any» considerable distances by belt or > ments, and a cylindrical tank or‘receiver 9 for other continuous conveying means. Pneumatic ejectors have been proposed for‘ handling wastes of this type, but in general, they have proven unsatisfactory and unreliable 'in operation. For bottom 'section Il which is directly connected by an elbow I3 to a discharge pipe I5 which may be of any length. The upper end of the receiver receiving and containing the waste _or other material being >handled by the apparatus. yThe receiver il is provided. with a conically shaped . 9 is closed byV a suitable cover I1 having a example, a source of serious trouble in the prior 20 iianged, inlet pipe connection I9 in the central devices has been the valves employed in the portion thereof. The various parts ~of the re- ` discharge side of the ejector apparatus. These ceiver 9 may be made of welded plate, or of cast valves became fouled and inoperative in very or of other -suitable material. The ` -dis- l short periods of time requiring- such frequent charge end of the receiver 9 is normally open> cleaning that use of the ejector becomes un 25 at all times and is connected directly to the economic. Other difficulties haveV been equally discharge pipe I5 without the use of any valves or equivalent structure. A manhole 20 is pro troublesome. The present invention, as will hereinafter ap vided tovpermit accessl to theinterior of the re pear, overcomes the disadvantages of the prior art structures and makes possible the elimina 30 A combination hopper and inlet valve struc tion of certain of the trouble producing valves ture is bolted or otherwise attached tothe re ceiver inlet pipe I9. This structure includes a v and other apparatus which have heretofore " ceiver. in a cylindrically shaped inner section 23 adapt larly adapted for use in connection with this ejector unit. ’I'he details of >the apparatus and In the drawings: 1 . valve 2B. and a suitably shaped valve body 21 which may conveniently include flanges 29 for facilitating its connection to the flange il at the upperend ofthe receiver inlet pipe I9 and the ñange 3l at the lower end of the hopper 2l. 'I'he iiapper vvalve 25 is hingedly supported within the valve satisfactory. The invention includes a novel ejector unit and a novel control system particu one preferred >embediment thereof. v . ed to be closed by a circular iiapper ' ation pneumatic ejectors and systems in ac cordance with the invention have proven highly - ing drawings andthe following description of l conically shapedhopper 2i, which terminates been considered ,essential parts of pneumatic ejector systems. In actual experimental oper the various advantages of the invention will be made apparentv by reference to the accompany . . >body'21formovement‘from a normal open tion. as illustrated in Fig. 1, to a closed position v in which position it seats against the lower 45 Fig. 1 is a side elevational view. partially in section, illustrating the features of an ejector unit constructed in accordance with the present invention vand certain associated apparatus; Wg. 2 is an enlarged, fragmentary view illus trating certain of the details of the control -electrode and mounting which constitutes a part of the apparatus of Fig. 1; Figs. 3 and 4 are enlarged sectional views I illustrating diagrammatically certain of- the 55 surface oi' the cylindrical hopper section 22. . In the structure illustrated, the fiapper valve 25 is actuated by an-air driven piston 35 which moves in a suitable cylinder 21 supported on the upper .end of the receiv . The piston 35 is operatively connected -to lthe flapper valve 25 by vsuitable linkages 39 and Il. When in its vertical or open position, as illustrated 'in Fig. 1, the dapper valve 2l is outof the way of the material which is dischargedl into the receiver 9 through the'hopper 2l. This prevents mate ¿ad assenti which might impair `the operation of the valve from collecting on the valve face. ‘Ti‘i'ie discharge end of a belt conveyor arranged discharge into the hopper 2| is illustrated at s3 in Fig. 1. It will be understood that the means whereby the material to be handled by the ejector is delivered to the ejector receiver 9 is not an important part of the invention. The invention contemplates, however, that the de livery means can be placed under the control of the ejector control system, so ß to provide for interrupting the delivery of the waste ma switch tI to the hand position, or in response to the operation of a relay controlled by the electrode #i5 when the main control switch 8| `is in the automatic position, a series of oper ations will take place in predetermined time sequence. The ñrst operation in this sequence effects the stopping of the conveyor d3. Next, the ilapper valve 25 is operated to close the inlet opening in the top of the receiver 9. Next, pressure air is admitted to the receiver il for a predetermined period'of time. This air ef fects the ejection of the material in the receiver. material to the ejector apparatus during the As soon as the election operation is completed, actual ejection operation. v the fiapper valve 25 is reopened, and the con A control electrode, 45 is supported on the 15 veyor 43, or other delivery means is again put head of the receiver so as to extend downwardly in operation, the pressure air having been pre into the receiver 9 as illustrated in Fig. 1. The viously shut oiT. The complete apparatus is support means for the electrode 45, as illustrated then restored to its original condition, and it in Fig. 2, includes an insulator 41 and a metallic, is ready for the next cycle. cup shaped, insulator guard or shield 49 which is 20 The control means utilized for accomplishing disposed about the upper end of the electrode this operation sequence includes a single pole, 45 and the lower end of the electrode insulator single throw induction relay, the operation of 41 and which opens into the interior of the re which is controlled automatically or manually -ceiver 9, as illustrated particularly in Fig. 2. in accordance with the position of the main The electrode 45 and the insulator 41 are me 25 control switch 8|, a motor driven timing «mech chanicaly connected to the electrode guard by means of a union 5| or like means to permit convenient removal of the electrode from the receiver for inspection or replacement. The anism which includes eight, single pole, single throw switches labeled Ti to Ts inclusive, a single pole, single throw, time interval relay, three double pole. single throw electro-magnetic re union 5| provides a gas tight seal. A conduit 30 lays RI, R2, and R3, one single pole, single box 53 having a removable, gasket sealed cover throw electro-magnetic relay R4, a normally 55 of conventional type is provided at the upper open single pole, single throw pressure switch, end of the electrode assembly for protecting the electrical connections. s s An .air inlet pipe 55 of substantial diameter is connected at one end to the valve body 21. The other end of the air inlet pipe 55 is con nected to a source of pressure air through an elbow 51, pipe lengths 58, 59, and 60, a T con nection Si, and a normally closed electrically operated valve 63. Air pressure is supplied to the operating piston 35 for the iiapper valve 25 through a three-Way, power operated valve 65, elbow ñttings 61, and suitable pipe sections 09, l0, 1|, 12, and 13. The initial pipe section 69 45 and a line starter or other electrically operated control means for the conveyor. Referring particularly to the wiring diagram of Fig. 5 and the schematic diagram of Fig. 6, the electrode is connected to the A or automatic terminal of the main control switch 8| by the conductor 83. The central terminal of the switch 3| is connected to one side of the oper ating coil 85 for the induction relay by the conductor B1. The other side of the operating coil 85 for the induction relay is connected to the H terminal of the main control switch 8| -by the conductor 89. One terminal of the connects with the T connection 5| in the main normally energized coil 9| of the induction relay supply line. ' . is connected to the L| side of the power supply The three way valve 65 is normally in the for the control circuit through the conductors position illustrated in Fig. 3. In this position the connection to the source of pressure air pro 50 93 and 95. The other side of the normally energized coil 9| of the induction relay is con vided by the pipes 69 and 10 is shut ofi’ and the nected to the L2 side of the line by the con' piston chamber 31 is vented to the atmosphere ductor 91. The induction relay is of the single through the pipe sections 13 and 12, elbows 61 pole, single throw type and is normally in the and the vent pipe sections 15 and '56. open circuit position. The valve 65 may be of any standard type. 55 The induction relay contacts IRC are con The particular device illustrated in the draw nected in parallel across the contacts R|A of ings is an electrically operated valve, and in the A pole of the two pole, single throw, elec cludes a T-shaped body 11 within which the tro-magnetic relay R! by conductors 99 and |0|. valve element 19 is adapted to be moved from the normal position of Fig. 3 to the position il 60 One side of the paralleled contacts IRC of the induction relay and the contacts RIA of the lustrated in Fig. 4 upon the energization of a A pole of the electrmmagnetic relay RI is con» suitable solenoid indicated at |8|. When in the nected to one side of the single pole, single _position of Fig. 4, the vent pipe 15 is closed, and throw, normally closed, time interval relay by pressure air is permitted to flow from the sup the conductor- |03, and thence through the conply line 10 into the pipe section 1| which is con tacts of the time interval relay to the line L2 nected to the upper end of the piston chamber by the conductor |05. The other side of the par 31 for the dapper valve operating piston 35, as alleled contacts IRC and RIA is connected to previously described. ' one side of the operating coil |01 for the time The features of a preferred control system are illustrated in Figs. 5 and 6. This system is ar 70 interval relay by the conductor |09, and to one side of the operating coil ||| for the relay Rl ranged for either automatic or manual oper by the conductor H3. The other side of the ation. and it includes a single pole, .double throw operating coil |01 for the time interval relay automatic-oiï-hand switch 8| as the main con is connected to the line L| through the con trol element. The control system is so arranged ductor the other side of the operating that in response to the movement oi the main 75 coil i||95,forand the relay Ri is connected to the 3 2,380,651 One side of the operating motor TM for the line starter. Power is supplied to the electro magnetic operating coil |19 of the line starter timer is connected to the line LI through the conductors II1 and 95. The other side of the includes the conductor |8I and the push button timer motor is connected to the L2 side of the line through the contacts RIB of the B pole of the switchPBI. The L2 Connection for the operating coil |19 relay RI, the connectors IIS, |2I, |23 and |05 for the line starter includes the push button switch PB2 (if used) the conductor |83, the relay line L2 through the conductors II5, I|1 and 95. providing the electrical connections. The con tacts RIB of the B pole of the relay RI are paralleled by the ñrst set of contacts TI of the timer; the circuit being provided by the conductor I2| vand the conductor |25 which connects to the L2 side of the line. A pilot light |21 is connected in parallel across the timer motor TM to indicate when that motor is in operation. The circuit to .the pilot lamp is provided by the conductors |29, I 3| and I I 9. - The L2 side of the timer motor TM is also con« nected to one side of the operating coil |33 for the single pole, electro-magnetic relay R4 through the normally open contacts T1 of'the timer switch and the conductors |35, |31 and H9. The other side of the operating coil |33 of from the lines LI and L2. The circuit from LI contacts R4A, the conductors |35 and |81, thence through the normally open timer switch T8 and the conductors |89 and I9I to the L2 side of the line. The timer switch T2 is paralleled across the contacts RIIA of the relay R4 by means of the conductors |85 and |93. The contacts of the auxiliary line starter switch LSA are paralleled across the contacts of the timer switch T8 by the conductor |89, and the conductors |95, |85, and |81. The LI side of the operating coil |33 for the relay R4 is connected to the LI side of the line by the conductors |39, I4I, I I1 and 95. The L2 side of the operating coil |33 is connected to the L2 side of the line through the normally open timer switch T1 and the paralleled contacts of the timer line through the conductors |39, |4I, II1 and 95. 25 switch TI and the A pole of the relay Rl'as previ The two-pole, electro-magnetic relay R3 con ously described. The operation of the control system will best stitutes the operating‘relay for the main air valve 55. One side of the operating coil |43 for this be understood by reference to the schematic dia the relay R4 is connected to the L| side of the , gram Fig. 6, which illustrates the control system of this relay are connected to the line LI by the 30 in the normal position for automatic operation. It will be noted that the timer motor TM and the conductors | 4|, II1, and 95. The other contact pilot light |21 are deenergized. The operating H3A of the A pole of the R3 relay is connected coil |19 for the line starter is energized through to the control solenoid for the air valve by the conductor |45. The L2 side of the operating coil the push button or safety switch PBI (and P132, |43 for the R3 relay is connected to the line L2 35 if used), the normally closed timer contacts T2, relay and one of the contacts RBA of the A pole through the normally closed timer switch T6 and through the normally open contacts R3B of the B pole of the relay, the connections being made by the conductors I41, |49, |5I, |53, |55, and |25. The contacts RBB of the B pole of the R3 relay are paralleled by the normally open contacts T4 of the timer relay, the connections being made through the conductors |5I, |51 and |49. The R2 relay is used as the control relay for the solenoid 8| which effects the operation of the ‘ u. three~way valve. AOne side of the valve solenoid 8| is connected to the L2 side-of the line by the conductor |59. The other side is connected >to one of the contacts RZB of the B pole of the R2 relay by the conductor ISI. The other of the contacts RZB is connected to the LI side of the line through the normally closed timer switch T5 by the conductors |53, |65, II'I, and 95. The timer switch T5 is ‘paralleled by the normally open, pressure switch |61 and by the conductors ' |69, 93 and 95, which tie to the LI side of the line. The L2 side of the operating coil I1I for the relay R2 is connected to the L2 side of the line through the RZA contacts of the A pole of the R2 relay by the conductors |13 and |25. The -R2A contacts are paralleled by the >normally opened timer sitch T3, the connections being made by the conductors |15 and I 55. The L! side of the operating coil I'II for the relay R2`is tied to the conductor |33by the conductor |11 and the circuit is completed to the LI side of the line through the paralleled pressure switch and timer switch T5 by the conductors IE5, II'I, and _ 95 or by the conductors |61, |69, 93, and 95. and the line starter auxiliary switch LSA. The apparatus is so arranged that the line starter for the conveyor motor must be initially started by manual operation. This is a safety precaution. The operating coils for the relay RI, R2, R3 and R4 are deenergized, and the contacts of the pres sure switch are open as illustrated. Assuming that the conveyor 43 or other means is operating to discharge the waste or other ma terial which is to be ejected into the ejector receiver, the material will collect in the receiver 9 until it contacts a predetermined length of the electrode 45 whereupon the operating coil 85 of the induction relay will be suiiiciently energized to eli’ect the operation of the induction relay. The operation of this relay closes the relay con« tacts IRC and thereby effects the energization of the operating coil III for the relay RI and the o_1_:>eratim,>r coil |81 for the time interval relay. The relay RI then operates the contacts RIA and RIB which are closed. The contacts RIA parallel the contacts IRC of the induction relay, and the contacts RIB effect the energization of the timer motor TM. . The time interval provided by the dashpot or other time delay means of the timer interval relay is made suliiciently long to assure lthe ruiming of the timer motor TM for a sufficient period to effect the closing of the normally opened timer switch TI which parallels the relay contacts RIB, and as soon as the timer switch TI is closed, sub~ sequent operation of the timer motor is controlled by the timer contacts and becomes independent of the relay RI. Operation of the timer inter The operation of the line starter is controlled 70 val relay de-energizes the operating coil ' I II of the .relay RI and the operating coil I 91 of the time interval relay. Beth relays then return to netic relay R4, the timer contacts T2 and T8, kthe the normal position. push button switches PBI and FB2, and a pair of auxiliary contacts LSA which are opened and As the operation of the timer proceeds, the closed in sequence with the line contacts of the 75 contacts T2 are opened. This de»encrgizes the by the single pole, normally open, electro-mag 4. 2,380,651 conveyor, and opens the auxiliary contacts LSA -other' delivery means to start up. The timer contacts T2 are now -or previously may have of the line starter. been closed. operating coil H9 ofthe line starter, stops the l The timer contacts T3 are next to close. This effects the energization of the operating coil lll of the relay R2 which controls the operation of the three-way valve E55, the circuit being com pleted through the still closed timer contacts T5. Energization of the operating coil VH for the relay R2 causes the relay contact RZA and REB to close. REA parallels the timer contacts T3 and holds ' Further operation of the timer contacts opens the contacts T1 which de-energizes the relay R4, thereby causing the relay contacts R4A to be opened and the LSA contacts to be closed; opens the timer contacts T8, and finally opens the con tacts Tl which stops the timer motor TM. The conveyor motor continues to operate notwith standing the lopening of the contacts TS and R4A since these contacts are paralleled by the then closed contacts LSA and T2. The timer appa quent opening of the timer contacts T3. The ratus and the complete control system is then closing of the RZB contacts of the relay R2 effects restored to the normal running position, as illus the energization 4of the three-way valve 65 through trated in Fig. 6, and is ready to repeat the cycle. a circuit which is completed by the closed timer The pilot light |21 is lit when the timer motor contacts T5. TM is energized and provides a convenient means The operation of the three-way valve E5 moves for indicating when the timer mechanism is run the control element "at of that valve from the po sition of Fig. 3 to the position of Fig. 4, and 20 ning. If it is desired to operate the apparatus under admits pressure air to the top of the piston 35 hand control this may be done by moving the which operates the flapper valve 25. The :dapper main control switch t! to the H or hand operated valve 25 then closes, and is held in a closed posi position as shown by the schematic diagram of tion by the pressure air. Fig. 6. Movement of the control switch 8l to ` The timer contact Tet is next to operate and this position will effect immediate operation of this effects the energization of the operating coil the induction re1ay,and the samesequence of con E43 for the relay R3» which controls the opera trol operations as previously described will take tion of the main air valve t3, the circuit being place. ït is also possible to effect the operation completed through the still closed timer con of the apparatus by the use of a cyclic timing tacts TS. Operation of the relay R3 closes relay means. To do this. the main control switch is contacts RSA which energizes the main air valve put into automatic position, and a, cyclic control 53 and also closes the RBB contacts which switch of any standard type is connected across parallel the timer contacts T4 thereby permitting the terminals of the operating coil of the induc the relay R3 to hold independently of the sub tion relay in place of the electrode connections. sequent. opening of the timer contacts T4. Oper An important feature of the invention is the ation of the air valve 633 admits pressure air to means provided for effecting automatic clean the top of the receiver 9 through the main inlet ing of the electrode shield (t9 which is illus pipe 55 for a period which is determined by the trated particularly in Figs. 1 and 2. The elec time interval between the closing of the timer 40 trode shield A9, as previously described, is a contacts Tt (which operates the relay R3) and cylindrical cup extending downwardly into the the opening of the timer contacts T6. Opening receiver tank 9 and the electrode 45 is locat of and thecauses timer the contacts air valve T6 de-energizes t3 to be shut theoff. relayThe ed centrally of this cup. During normal op eration it has been found that there has been period of time during which pressure air is the relay energized independently of the subse admitted to the interior of the receiver can be readily varied in accordance with the material being handled. Admission of pressure air to the interior of thc receiver effects the operation of the pressure switch which is in parallel with the timer contact T5. Hence, the opening of the timer contacts T5 ' a tendency for material to collect in this shield and since this sometimes adversely affects the operation `of the control mechanism, an automatic cleaning means for the electrode shield and insulator has been. provided. This constitutes a jet type, air inlet lill which 50 means is supported in the upper end of the shield 49 and is arranged to direct a stream of air cir (which occurs at about the same time as the open cularly of the shield in the region of the elec ing of the timer contacts T6 to eiîect closing of the trode insulator al. This jet tube §91 is con main air valve 63) does not de-energize the con trol relay R2 for the three-way valve 65 and that 55 nected to the main air inlet pipe 55 by a suit able conduit lSQ, and it will be noted that air valve remains in the Fig. 4 position until the will be caused to flow through the jet tube |97 ejection of the contents of the receiver lowers during each operation of the apparatus. the pressure sufficiently for the pressure switch The ejector apparatus described in the fore to open. At this time.- since the contacts T5 have previously been opened and are still open, the 60 going, is a much simpler and much more satis factory device than the arrangements previously' operating coil ill for the'relay R2 will be de known to the art. A particular advantage of the energized, the contacts REA and RZB opened and apparatus consists in its use of only one valve the three-way valve 65, permitted to return to its at the inlet end of the ejector, as contrasted with normal position illustrated in Fig. 3. When this the use in the prior structures of a valve or occurs, the cylinder 3l for the valve operating valves at both the inlet and the outlet ends of piston 35 is vented to the air, and the flapper> the receiver. The elimination of all valves ex valve 25 thereupon returns to its open position. cept for the single valve at the inlet end of the Subsequent operation of the timer effects the receiver is a most important feature of the in closure of the contacts Tl which energizes the operating coil §33 for the relay R4 and closes the H vention and contributes substantially to its im proved reliability of operation. contacts RHA of that relay. At about this same Various types of pneumatic ejectors and con time the timer contacts T8 are also closed, and trol systems therefor may be constructed in ac the circuit for the operating coil H9 of the line cordance with the principles disclosed in the starter or other control means for the conveyor 43 is re-energized. This causes the conveyor or 7 5 foregoing. Accordingly, it is my desire that the 2,380,651 accompanying claims shall be given the broad est reasonable construction consistent With the 5 gated, upright receiver having an inlet vopening adjacent its top and an outlet opening adjacent language appearing therein. its bottom, conveyor means actuable to deliver material to be handled by said apparatus into said receiver through said inlet opening, a flap valve movable to open and to close the said in ing adjacent its top and an outlet opening ad let opening in said receiver, means including a cylinder and a piston movable in said cylinder for jacent its bottom, conveyor means actuable to deliver material t0 be handled by said apparatus operating said flap valve, a source of pressure into said receiver through said inlet opening,-a 10 air, means_including a conduit and a three-Way, electrically operated valve for connecting said flap valve movable to open and to close the said source of pressure air to said piston and cylinder, inlet opening in said receiver, an air motor for operating said flap valve, a source of pressure said three-way valve being movable from a nor' air, means including a conduit and a three way mal vent position, in which position said source valve for connecting said source of pressure air of pressure air is disconnected from said piston and cylinder and said cylinder is vented to the to said air motor, said three Way valve being atmosphere, to an operating position, in which movable from a normal vent position, in which position said source of pressure air is discon position said vent is closed and said piston and cylinder are.connected to said source of pres nected from 'said air motor and said air motor is vented to the atmosphere, to an operating po 20 sure air, means including other conduit means ì and an electrically operated. main air valve for sition, in which position said vent is closed and connecting said source of pressure air to the up~ said air motor is connected to said source of pres sure air, means including other conduit means per end of said receiver, said main air valve and a main air valve for connecting said source being movable from a normal closed position, in of pressure air to the upper end of said receiver, 25 which position said source of pressure air is dis said main air valve being movable from a nor connected from said receiver, to an operating po mal closed position, in which position said source sition, in which position pressure air is admitted of pressure air is disconnected from said receiver, to the upper endof said receiver, and electrically to an operating position, in which position pres operated control means, including a motor driven sure air is'admitted to the upper end of said re-k 30 timer and a relay for operating each of said elec ceiver, and an electrical control means includ trically operable valves, which is actuable to ing a timer mechanism Which is operable to ef eiïect sequentially the stopping of said conveyor, I claim: l. In apparatus of the class described, an elongated, upright receiver having an inlet open fect sequentially the stopping of said conveyor, movement of said three-way valve to the operat the movement of said three Way valve from the ing position thereof, thereby effecting movement normal to the operating position thereof, thereby 35 of said flap valve to the closed position, opera eiîecting movement of said flap valve to the tion of said main air valve to admit pressure air closed position, operation of said main air valve to the upper end of said receiver for a predeter to admit pressure air to the upper end of said mined period of time suñicient to accomplish the receiver for a predetermined period of time suf pneumatic ejection of the contents of said re ficient to accomplish the pneumatic ejection of 40 ceiver, the closing of said main air valve, move the contents of said receiver, the reclosing of ment of said three-Way valve to said normal said main air valve, movement of said three Way vent position whereby said piston and cylinder valve to said vent position whereby said flap -are vented and said ñap valve is opened, and valve is reopened, and the starting up of said the starting up of said conveyor, said receiver conveyor, said receiver outlet being open at all 45 outlet being open at all times during the opera times during the operation of said apparatus. ' tion o-f said apparatus. 2. In apparatus of the class described, an elon HAROLD T. JEFFERY.