US2221741A

US2221741A - Pneumatic conveying apparatus

Info

Publication number: US2221741A
Application number: US196168A
Authority: US
Inventors: Vogel-Jorgensen Mikael
Original assignee: Fuller Co
Current assignee: Fuller Co
Priority date: 1937-03-24
Filing date: 1938-03-16
Publication date: 1940-11-12
Anticipated expiration: 1957-11-12

Description

Nov 32, 1940. M. VOGEL-JORGENSEN 2,221,741

PNEUMATIC CONVEYING APPARATUS Filed March 16, 1938 3 Sheets-Sheet l \NVENTOR M/KAH V0651 110/?55/55 Zi )& 5 ATTORNEYS VOGEL-JORGENSEN 2 L PNEUMATIC CONVEYING APPARATUS Filed March 16, 1938 3 Sheets-Sheet 2 INVENTOR M/MEL 1 0 51 vommmv ATTO RN EYS NW 12, 1949. M \{QGEL-JORGENSEN 2,221,741

PNEUMAT I C CONVEYING APPARATUS Filed March 16, 1938 3 Sheets-Sheet 3 (QM, aw

ATTORNEYS Patented Nov. 12, 1940 UNITED STATES PNEUMATIC CONVEYING APPARATUS Mikael Vogel-Jorgensen, Frederiksberg, near 00.

en, Denmark, assignor, by mesne assignments, to Fuller Company, Borough 01 Catasauqua, Pa, a corporation of Delaware Application March 16, 1938, Serial No. 196,168 In Great Britain March 24, 1937 4 Claims. (01. soc-53) This invention relates to apparatus for pneumatically conveying powdered, granular or pulverulent material in a quasi-liquid state of the kind in which the material is admitted to a container in batches and each batch is expelled from it by compressed air.

In apparatus of this kind there is usually an inlet valve for controlling the admission of the material to the container and an air valve for controlling the admission of compressed air to the container. In order that the apparatus may work automatically means must be provided to reverse the valves when the container is full and when it is empty.

According to this invention a so-called toplevel indicator, which is biased toward its normal position, is deflected to a second position when the pulverulent material accumulating in the container reaches it and presses upon it. This results in a closing of the inlet valve to stop the supply of pulverulent material, and an opening of the air valve to blow the material from the container through a discharge pipe. The indicator is latched or releasably retained in the deflected position even after the level of the pulverulent material drops below it and until substantially all of the material is discharged from the container, whereupon a bottom-level indicator, which is also biased toward its normal position, and which has been held in a. deflected position by the pulverulent material pressing upon it, now moves back to its normal position and this brings about a release of the top-level indicator so that it returns to its normal position and reverses the valves. The releasing of the top-level indicator may be brought about by other predetermined conditions such as the lower air pressure condition which exists in the container when it has been emptied of its pulverulent material, or when two-containers are arranged in parallel so that one is discharging while the other is charging, the release of the top-level indicator in one container to reverse the valves and initiate charging in that container may be brought about when the second container becomes full and when the top-level indicator of the second container moves to its deflected position to close its inlet valve and open its air valve.

Several forms of apparatus constructed in accordance with the invention are illustrated diagrammatically in the accompanying drawings in which:

Figure l is a vertical section of a single container having associated therewith both a toplevel indicator and a bottom-level indicator for controlling the reversal of the main valves;

Fig. 2 is a schematic view illustrating the operation of the relay or control valves which are actuated by the top level indicator and the bottom level indicator;

Fig. 3 is a vertical section of a portion of the container shown in Fig. 1 illustrating a modification in which the air valve may be mechanically connected with the inlet valve so that when the inlet valve is open the air valve is closed and vice versa.

Fig. 4 is a vertical section of a portion of the container shown in Fig. 1 illustrating a modification in which no bottom-level indicator is employed and the releasing of the top-level indicator is brought about by the lower air pressure condition existing in the container when it has been emptied of its pulverulent material;

Fig. 5 is a vertical section of two containers arranged in parallel and provided with interlock mechanism;

Fig. 6 is a vertical section through two containers arranged in parallel illustrating a modification in which the bottom-level indicator is omitted in each container and the release of the top-level indicator in one container to reverse the valves and initiate charging in that container is brought about when the second container becomes full.

Fig. 7 is a schematic view illustrating the operation of the relay valves of Fig. 6.

Referring first to Figures 1 and 2, the material to be conveyed is fed to the container I through a pipe 2 controlled by the inlet valve 3. In the drawings the apparatus is shown in the charging position so that the valve 3 is open.

The top level indicator comprises a plate 4 carried by an arm 5 which is mounted to rock about a pivot 6. An arm 1 moves with the arm 5 and carries a weight 8 which tends to turn the arms 5 and l in a counter-clockwise direction and tends to retain the plate 4 in the position shown in Fig. l which for convenience will be referred to as its first position. The arm 5 is mounted in a tube or shield 28 which forms a complete enclosure except that it has free communication at its lower end with the interior of the con tainer as indicated at 28'. One lateral wall of the shield 28 is provided with an opening 4' which is substantially closed by the plate 4 when this plate is in its first position. It willnow be noted that when the material in the container rises to the level of the plate 4 it exerts pressure only on that side of the plate which faces outwardly from the enclosure, because when the material is rising in the container the plate 4 is rocked before any material can arrive behind it. When the level of the material in the container is at orabove the plate 4 the material presses upon it and swings the plate toward the interior of the enclosure to the position shown in Fig. 2 which for convenience will be referred to as its second position. This movement of the plate 4 swings the arms 5 and 1 in a clockwise direction.

When the material in the container falls again The apparatus illustrated makes use of compressed air for the operation of all the main valves. The relay valve 41 controls the supply of compressed air to the various pistons which operate the main valves. Compressed air is supplied to the casing In of the relay valve 4| through a pipe II which communicates with the main air conduit When the container is charging, relay valve 41 is in its lowermost position and then the compressed air leaves the casing I of the relay valve through a pipe I211. The pipe |2a conducts the air to a cylinder |5 in which a piston 4 is moved by the air against the action of a spring 32. The rod of the piston I4. is pivotally connected to one end of a lever l3 which is pivotally mounted intermediate its ends as indicated at l3. Theother end of the lever I3 is connected to the inlet valve 3. When the piston |4 moves upwardly in its cylinder it opens the inlet valve 3 as shown in Fig. 1. Air is also supplied from the pipe |2a to a cylinder l9 through a branchpipe. |2'. In this cylinder there is a piston I9 connected to a valve |9a which controls an opening in the container I. Air supplied to the cylinder l9' moves the piston l9 against the action of a spring 33 thus opening the valve |9a and permitting air to escape from the container during charging.

When the relay valve 41 is moved to the position shown in Fig. 2 the supply of compressed air to the pipe I21; is cut off and this pipe is placed in communication with the atmosphere so that air escapes from the cylinders l5 and I9 thereby allowing the spring 32 to close the inlet valve 3 and the spring 33 to close the air escape valve I90. The compressed air is then directed by the relay valve 41 through a pipe |2b to a cylinder It in which a piston I1 is mounted. The piston is moved by the air pressure against the action of a spring 34 to lift a valve l6 off its seat. When this valve is open compressed air from the main supply conduit passes to a perforated distributing ring positioned in the middle of the con- When the relay valve 41 moves to the upper position shown in Fig. 2 a latch 5| on a bell crank lever 52 engages behind a projection 5| on the valve rod 9 and holds the valve 41 and the plate 4 in the position shown in Fig. 2 until this latch is released. The bell crank lever 52 is connected to a piston 53 operating in a cylinder 53' formed in the casing Hi. When an is supplied to the cylinder 53' through a pipe 35 the piston 53 is moved against the action of a coil spring 53" and thereby swings the bell crank lever 52 in a clockwise direction to release the latch 5|. When the during discharging any portion of it which has" air pressure in the cylinder 53' is released the coil spring 53" rocks the bell crank lever 52 in an anticlockwise direction so that it will be in a position to engage the projection 54 the next time the valve stem 9 moves upwardly.

In the lower portion of the container there is positioned a bottom level indicator having a plate Y 23 carried by an arm 24. 'A tube or shield 23 forms an enclosure which has free communication at its lower end with the interior of the container as indicated at 29'. The lateral wall of the shield 23 is provided with an opening 3| which is substantially closed by the plate 23 when this plate is in its first position. An arm 24' moves with the arm 24 and carries a counterweight 25 which tends to move the arms 24 and 24' in a counter-clockwise direction and thus tends to retain the plate 23 in its first position in which it substantially closes the opening 3|. The arm 24' is pivotally connected to the rod" of a control valve 48 moving in a cylinder 21. This valve controls the supply of compressed air to the cylinder 53' of the latch mechanism. For this purpose a pipe 36 supplies air to the cylinder 21 from the main air conduit When the valve 48 is in the position shown in Fig. 2 the cylinder 53' of the latch mechanism is in communication with the atmosphere through the pipe and the exhaust vent in the valve casing 21 thus allowing the latch 5| to assume its operative position. However, when the valve 43 is in its lowermost position the air pipe 36 supplies compressed air to pipe 35 and lifts the piston 53 of the latch mechanism to thereby release the latch 5|.

, The operation of the particular form of apparatus so far described may be briefly summarized as follows: Assuming that the container is being charged with material, the parts will be in the position-shown in Fig. 1 with the inlet valve 3 open to admit the material to the container. The

valve |9a will be open to vent the container and permit the escape of. air from it. The top level' indicator 4 will be in its first position and the relay valve 41 will be in its lowermost position supplying air to the cylinder IQ of the vent valve I31:

and to the cylinder I5 which operates the inletvalve. Themain air inlet valve l6 will be closed because the'cylinder l8 has been, placed incomimunication vwith the atmosphere by reason of the relay valve 4| being in its lowermost position. The bottom level indicator 23 will be in its second position because the material in the container is pressing upon it and therefore the control valve 48 will be in the position shown in Fig. 2 thereby placing the cylinder 53' of the latch mechanism in communication with the atmosphere allowing the spring 53" to urge the latch 5| toward the rod 9 of the relay valve 41. When the materlal in the container reaches the level of the top indicator 4 this indicator will swing to the-position shown in Fig. 2 (its second position) thereby moving the relay valve to the posi- '-tion shown in this figure and this results in closing the inlet valve 3, the vent valve |9a and opening the main air valve IS. The latch 5| snaps behind the-projection 5| on the valve rod forces the mixture of air and material through the discharge pipe 22. When the level of the material falls below the bottom level indicator 23 this indicator is swung by its weight 25 in a counter-clockwise direction to its first position in which it substantially closes the opening 3| in the 5 shield. This results in a downward movement of the control valve 48 thus admitting compressed air to the cylinder 53 of the latch mechanism and thereby releasing the latch. This permits the weight 8 to swing the top level indicator 4 10 back to its first position shown in Fig. l whereupon the air valve I6 is closed, and the inlet valve 3 and vent valve I 941 are opened. When the inlet valve 3 is first opened and enough material accumulates in the bottom of the container I to reach the level of the bottom level indicator 23 this indicator is moved back to the position shown in Fig. 1. This exhausts the air from the cylinder 53 of the latch mechanism allowing the latch 5| to resume its operative position so that it can again engage behind the projection 5I when the top level indicator is subsequently deflected upon completion of charging. It will be noted that the control valve 48 operated by the bottom level indicator does not of itself afiect the supply 25 of compressed air to the operating means for the valves 3, I6 and I9a but instead it releases the latch mechanism which permits the top level indicator to return to its first position and it is this movement of the top level indicator that directly reverses the valves 3, I6 and I911.

Fig. 3 shows a modification in which the air valve I6 is operated by a direct mechanical connection from the lever I3 of the inlet valve 3. In this case the air valve I6 is operated by lever I6 connected by a link I6" to the end of the lever I3. Thus when the inlet valve 3 is opened the air valve I6 is closed and vice versa. When the two valves are thus mechanically interconnected the pneumatic operating means for the valve i6 shown in Fig. 1 at III8--34 is omitted and the pipe 1212 leading thereto from the casing I0 is also omitted. Otherwise the construction and operation of the modification shown in Fig. 3 is the same as that described above.

Fig. 4 illustrates a modification of the latch vmechanism for the top level indicator. In this case after the top level indicator has been defiected by the material and compressed air has been admitted to the container the pressure within the container holds a diaphragm 51! in its raised position thereby lifting an arm 58 which may be pivoted at one end to a stationary bracket as indicated at 59. The free end of the arm 58 carries a hook 66 which engages the arm I of the top level indicator and retains it in its raised position until all of the material is discharged from the container. The pressure in the container thereupon drops and permits the diaphragm 5i to return to its normal position thereby lowering so the hook and allowing the top level indicator to move back to its first position and reverse the valves. It will be understood that when this type of latch mechanism is employed the bottom level indicator may be dispensed with and the .65 valve casing simplified by omitting the cylinder 53' and its associated parts.

Fig. 5 shows two interconnected containers with the left hand container discharging and the right hand container charging. The material is supplied to the two containers through

inlet pipes

31 and 38 respectively and is discharged through pipes 39 and 46 respectively. The discharge pipes 39 and 4D meet at the common discharge pipe 4! and a freely mounted fiap valve 58 closes the exit end of either the

pipe

39 or 40 depending upon which one is discharging. Compressed air is supplied from the

main air conduits

43 and 44. The pipe II2b of the left hand container, which corresponds with the pipe I2b of Fig. 1, does not run directly to the cylinder I I8 5 of the corresponding container but first runs to the neighborhood of the cylinder 2 I8 of the right hand container. At this point a valve 45 controls the fiow of air through the pipe II2b. This valve is mounted to move with the main air valve 10 MS of the right hand container. Similarly a valve 45 is mounted to move with the main air valve I I6 of the left hand container and controls the flow of air through the pipe 2I2b associated with the right hand container. 15

When the left hand container is discharging, the compressed air and material passing through pipe 39 force the flap valve 56 over to the right hand position and this prevents any material from passing through the pipe 40 into the right 20 hand container. If the left hand container-is completely emptied before the right hand container is full the level indicators in it will operate to reverse the valves, and the valve 46 being open (because the main air valve 2I6 of. the 25 right hand container is now closed) nothing will prevent this reversal. Accordingly, both containers will be charging simultaneously for a short time. When the charging of the right hand container is complete there will be nothing to 30 prevent its valves from reversing and it will begin to discharge. However, if the right hand container is filled before the left hand container is completely empty it will be prevented by the valve 45 from immediately beginning to dis- 35 charge. This valve prevents the compressed air from passing through the pipe 2I2b to the cylinder 218 until the lower level indicator in the left hand container moves to its first position in which it substantially closes the opening in its shield. This only happens, as previously pointed out, when the container is substantially empty, and when it does happen the main air valve IIG of the. left hand container is closed as previously described thereby opening the valve 45 and in consequence the right hand container can begin to discharge.

Thus it will be seen that the valves 45 and 46 and the associated parts constitute interlock mechanism whereby compressed air cannot be 50 admitted to one container to discharge its contents until the other container has been emptied.

Figs. 6 and 7 illustrate an arrangement which may be used when conditions are such that the time required for charging is longer than the 55 time required for discharging. Air is supplied from the

main air conduits

43 and 44 by means of pipes HI and 2H to the relay valves i4! and 247. The pipes lIZa, M211, M217 and 2I2b have the same purpose as previously described in 0011- go nection with the other figures. In this form of apparatus the bottom level indicators are omitted and a pipe I35 branches off from the pipe 2I2b and similarly a pipe 235 branches oil from the pipe 2b. With conditions as represented in 65 Figs. 6 and 7 there is no compressed air beneath the piston 553 of the latch mechanism of the left hand container (the pipe I35 being placed in communication with the atmosphere by relay valve 24? of the right hand container). The bell 7Q crank lever l52 will be in its operative position with the latch I5! engaging behind the projection I5I' on the rod of the relay valve I47, thus securing the level indicator of the left hand container in its deflected position n mm. on: a:

of the latch mechanism of the right hand container, however, will be in its upper position because compressed air has entered its cylinder through the pipe 235 from the pipe 22;. Thus the bell crank lever 252 will be in a position such that the latch MI is not allowed to come in contact with the projection 25| on the valve rod of the relay valve 241 when the latter is first moved upward. When the left hand container is completely discharged compressed air only will fiow through the discharge pipes 39- whereby these pipes will be thoroughly cleaned out. Shortly afterwards the level of the material in the right hand container will reach the level indicator and cause it to turn in a clockwise direction thus moving the relay valve 241 upwardly. Thereupon discharging of the right hand container will begin and compressed air will be admitted through the pipe I35 to the piston'l53 of the latch mechanism of the left hand container whereupon this latch mechanism will be released and the level indicator of the left hand container will assume its first position and charging of this container will begin. As soon as the relay valve I" reaches its lower position the compressed air beneath the piston '253 of the latch mechanism of the right hand container will escape through the pipe 235 and pipe 2b to the atmosphere above the relay valve I".

- Consequently the latch 25! on the bell crank lever 252 will then engage behind the projection 25? thereby securing the level indicator of the right hand indicator in its deflected position and preventing it from reassuming its first position when the level of the material drops below the indicator.

It will be seen that in the form of apparatus illustrated in Figs. 6 and'l when one container has been filled the deflection of the level indicator in that container by the pressure of the material upon it releases thelatch mechanism of the level indicator associated with the other container thereby opening the inlet valve of that container and starting the charging operation. In other words, when one container is full it initiates the charging in the other container.

I claim:

1. Apparatus forpneumatically conveying pulverulent material comprising a container, an inlet valve controlling the admission of the material to the container, two members located in the container and adapted to be deflected from one position to a second position when the-maverulent material comprising a container, an inlet valve controlling the admission of the material to the container, an air valve for controlling the admission of compressed air to the container, 'two members located in the container and adapted to be deflected from one position ta 9. second position when the material in the container presses upon them, one of said members being located in the upper part of the container and serving as a top level indicator and the other being located in the lower part of.

verulent material comprising a container, an

inlet valve in the upper part of the container adapted inits open position to permit pulverulent material to drop into the container and in its closed position to out 01f the supply of the material to the container, a member within the container so mounted as to remain permanently in the upper portion of the container, said member being biased toward one position which it assumes when the material within the container is not pressing upon it and when it is otherwise unrestrained but adapted to be deflected to a second position when the pulverulent material accumulating in the container reaches the member and presses upon it, means actuated by the movement of said member to control the movement of said inlet valve, latch mechanism for retaining said member in its second position while the material is being discharged from the container and after the level of the material drops below the member, and means operating on the latch mechanism under predetermined conditions lent material to drop into the container and in its closed position to cut ofifthe supply of the material to the container, an air'valve for controlling the admission of compressed air to the container, a member within the container so mounted as to remain permanently in the upper portion of the container, said member being biased toward one position which it assumes when the material within the container is not pressing upon it and when it is otherwise unrestrained but adapted to be deflected to a second position when the pulverulent material accumulating in the container reaches the member and presses upon it, means actuated by themovement of said member for controlling themovement of the inlet valve for the material and said air valve, latch mechanismfor retaining said member in its second position while the material is being discharged from the container and after the level of the material drops below the member,

and means operating on the latch mechanism I under predetermined conditions for releasing it, whereupon said member returns to its first position.

' MIKAEL VOGEL-JORGENSEN.