US2193738A - Pneumatic conveyer - Google Patents

Description

March 12, 1940. PERRlN 2,193,738

PNEUMATIC CONVEYER Filed May 21, 1958 3 Sheets-Sheet 1 INVENTOR Aw/hur M. P 1

ATTORNEY March 12, 1940. P IN 2,193,73a

PNEUMATIC CON VEYER Filed May 2l, 1938 3 Sheets-Sheet 2 v. INVENTOR A r M. far/e71 ATTORNEY March 12, 1940. A. M. PERRIN PNEUMATIC CONVEYER 3 Sheets-Sheet 5 Filed May 21, 1938 I N VE NTQ R -4/*/iar f1 Par/"in ATTORN Y Patented Mar. 12, 1940 3 UNITED stares earsnr oFFicE 2 Claims. (01. 302-62) This invention relates to pneumatic conveyers and more particularly refers to improvements in methods of and means for discharging material from such conveyers into storage tanks or the 6 like.

Pneumatic conveyers such as are used for the removal of ashes or comminuted material, and their discharge in a place of storage, generally consist of a receiving chamber connected by a 10 pipe line to the place from which the comminuted material is to be removed, andan'air pump or exhauster for creating a depression within the receiver; said receiver being provided with a discharge gate through which the material collected within the receiver is discharged into an underlying storage tank or the like.

In pneumatic conveyers of a type heretofore in use, the discharge gate of the receiver is so I the assistance of a counterweight, said gate being forced open by the weight of the material collected within the receiver whenever the pressure due to such weight is sufficient to overcome the force tending to hold the gate closed.

The exhauster or air pump operates continuously whether the discharge gate is in its closed or open position, although when the gate is open,

- the velocity of the air in the intake pipe leading the material to the receiver, will be considerably decreased.

This method of controlling the discharge of material from the, receiver has frequently been found tobe unsatisfactory, because when a certain quantity of the material within the receiver has been discharged, the weight of the remaining portion is no longer sufficient to hold the gate open, and therefore the gate will close before the material has been completely discharged.

40 When the material contains clinkers, or pebbles orlumps, some of these may become wedged between the gate and the edge of the outlet as the gate is closing, and as a result the gate will remain partially open; and will prevent the device from operating satisfactorily.

In order to correct this condition it has been proposed to insure a full discharge of the material from the receiver'before the gate can be closed by atmospheric pressure, this end being attained by controlling the operation of the air pump or exhauster by means of a timing device causing its operation to be intermittent, and to' cease at such times when a sufficient quantity of material has beencollected within the receiver to warrant its. being discharged; said quantity however being insufiicient to force the gate open against atmospheric pressure by virtue of its own through the outlet. The operation of the air 10 pump or exhauster is resumed only after sufficient time has elapsed to give a chance to the material within the receiver to be discharged in its entirety. Thus there is no danger of any clinkers or lumps interfering within the closure 1 of the gate when the operation of the air pump The primary object of this invention is to provide a novel and improved method of controlling the discharge of material from a receiver, forming part of a pneumatic conveying system.

'Another object is to provide a receiver of a novel and improved construction, adapted for use in connection with a pneumatic conveying system, said receiver being equipped with means for controlling the discharge of material therein collected, insuring reliable and satisfactory operation of the system as a whole, as Well as the con- 40 tinuity of operation of the conveying portion thereof.

A further object is to provide a receiver of a novel and improved construction, adapted for automatic and continuous operation in connection 45 with. a pneumatic conveyor system, insuring full operating capacity of the plant at all times;

A still further object is to provide, in connection with a chamber from which collected material in comminuted form is to be discharged, a novel arrangement of gate for controlling the discharge of the material through the outlet, whereby a full discharge of the material is assured independently of the air pressure conditions within or without the chamber. 6

Other objects and advantages of the present invention will more fully appear as the description proceeds and will be set forth and claimed in the appended claims.

My invention is illustrated. by way of example in the accompanying drawings in which:

Fig. 1 is a vertical sectional view of a receiver embodying the main features of my invention;

Fig. 2 is a fragmentary view in elevation of an arrangement for controlling the intermittent dis charge of material from the upper into a lower chamber of the receiver and from the lower chamber into a storage bin, or the like;

Fig. 3 is a vertical sectional view of a receiver embodying my invention in an alternative form;

Fig. 4 is a detail side view in elevation, partly sectioned, of a special gate used in connection with the receiver shown in Fig. 3;

Fig. 5 is a rear view in elevation of the same, partly broken away and sectioned;

Fig. 6 is a vertical cross section of a delaying device controlling the return movement of the gate shown in Figs. 3, 4 and 5;

Fig. 7 is a vertical sectional view of a receiver embodying my invention in an alternative form; and

Fig. 8 is a vertical sectional view of a receiver embodying my invention in still another alternative form.

In the arrangement shown in Fig. 1 the gates controlling the discharge outlets of the two chambers are closed entirely by atmospheric pressure. In said figure, l0 generally designates a receiver, mounted on a storage bin H, provided with a vent l2. The receiver comprises an upper, or receiving, chamber l3 having a funnel shaped lower portion l4, terminating in a discharge spout I5, and a lower, or auxiliary, chamber l6 located directly underneath said chamber l3, also having a funnel-shaped lower portion l1, terminating in a discharge spout l8, discharging directly into the storage bin.

The walls of the receiving chamber l3 are preferably made of a very hard material in order to withstand abrasion due to material being projected thereagainst. Said receiving chamber is connected with a supply of the material to be removed by a conveying pipe IS, the discharge end, 20, of which, is directed substantially at a tangent to the surface of chamber l3. An exhaust member 2| projects downwardly within chamber l3 and by means of an exhaust pipe 22 connects said chamber with a an exhauster 23, which is of the usual Venturi type, a suction being generated within said pipe by the action of a fluid under pressure supplied to the Venturi through line 24.

A duct 25 connects lower chamber IS with exhaust pipe 22. Said duct is normally closed by a damper 2S and is provided with an opening 2'! at a point intermediate said damper and chamber l6, said opening establishing communication between said chamber l6 and the surrounding atmosphere.

Opening 2'! can be closed by a closure member 28, pivotally mounted at 29, having an actuating arm 33. The arrangement is so designed that when damper 26 is closed member 21 is in open position and vice versa, said two elements being operatively connected to an actuator of any suit able character for their intermittent operation.

In the drawings the actuator is shown in the form of a hydraulically operated piston 3| movable within a cylinder 32, the operation of said piston being controlled by a small electric motor 33 inserted in a circuit 34, intermittently energized by a cam acting contactor 35. The outer end of the piston is shown connected to arm 36 which operates the damper and arm 30 which operates closure member 28. The piston is shown in its retracted position and it will be seen that when the piston is forced outwardly it will cause damper 26 to turn to its open position and closure member 28 to swing to its closed position.

The outlet 37 of discharge spout i5 is controlled by a gate or closure member 38, carried by an arm 39 pivotally mounted at 40. Another arm 4, carrying a counterweight 42, radially extends in a substantially horizontal direction from pivot 40, said counterweight being adjusted so as to normally hold the gate or closure member 38 in open position but not far from outlet 31.

In a similar manner outlet 43 of discharge spout I8 is controlled by a gate or closure member 44 carried by an arm 45, pivotally mounted at 46, said gate or closure member 44 also being normally held in open position but in relative proximity to outlet 43 by a counterweight 41.

The device is shown in its inoperative condition where both gates are open. As soon as the exhauster is started and a lower than atmospheric pressure is created within chamber IS, a current of air will be induced through outlet 31 of chamber l3, and said current will cause gate or closure member 38 to swing to its closed position where it will subsequently be maintained by atmospheric pressure so long as a suction is created within chamber I3. When the pressure within chamber I3 is sufficiently low material will be carried through pipe l9 and discharged into the receiving chamber l3. Due to the tangential discharge of pipe l9 with respect to chamber IS, a centrifugal separation of the material occurs within said chamber and the material will fall by gravity into the discharge spout and the lower portion of said chamber IS. The contactor 35 is timed so as to energize circuit 34 after a certain period when a sufficient amount of material has been collected within chamber l3. The energization of said circuit will cause the operation of the actuator, with the result that the air vent 21 will be closed and damper 26 will be moved to open position. Air will therefore now be exhausted also from lower chamber l6, so that the current of air induced through outlet 43 will swing gate 44 to its closed position.

As the pressure between the two chambers l3 and I6 becomes equalized gate 38 will swing open and will be forced wide open by the Weight of the material within chamber l3, which material will thus be discharged within chamber 16. Within a short interval the contactor 35 will have moved to a position where circuit 34 is again deenergized and piston 3i will be free to retum to its retracted position, being urged to such retracted position by the action of a spring or in any other suitable manner. This return movement of the piston will restore the original conditions in duct 25, so that air will be free to reenter chamber l6 through vent 2'! and a lower than atmospheric pressure will continue to be maintained only within upper chamber l3; it being understood that as soon as air at normal pressure enters chamber l6 gate 38 will again swing to its closed position and gate 44 will swing to its open position, allowing the material contained within chamber 16 to be discharged into the storage bin.

This cycle of operation is repeated in a continuous succession and while the discharge of the material from each chamber takes place intermittently the discharge of material through pipe it! takes placecontinuously due to the uninterrupted operation of the exhauster throughout. It is, therefore, obvious that the conveyor installation can be. operated a t-full capacity, while at l the same time full discharge of the material and ings 6|.

areliableoperationoi the gates are assured.

The device shown in Fig. 3 is in every respect similar to the one just described, except that the gate controlling the outletof the lower chamber is built on a different principle. All the parts of the device corresponding to those shown in Fig. 1am designated by the same reference numerals. The outlet 43 of discharge spout l8 is controlled by a gate' ls, which is normally held closed by a counterweight 49. The construction of this gate and controlling means therefor are shown in detail in Figs. 4, 5, 6. In thesame it is seen that the gate is carried by an arm-1'50 to which it is pivotally connected at 5|, said arm being fixed on a shaft 52, mounted on support 53.

Said shaft also extends through a box 54, which, together with its two end plates 55, 56, forms a water-tight cylindrical chamber 51. Within said chamber shaft 52 carries a plate 58, which extends diametrically and from one end to the other of chamber 51. Said plate is provided with'relatively large openings, such as 59, which are obstructed at one side by a spring member, such as shown at 6d, each spring member being provided with a relatively small opening 6|.

The spring members are arranged in relation to the relatively large openings 59 so as to permit free movement of. shaft 52 in a clockwise direction with respect to Figs. .3, 4, 6, plate 58 acting as a piston and springs 65 yielding against the currents of fluid flowing through openings 59. The fluid contained within chamber 51! is forced to pass through openings 59 when shaft 52 is rotated because box 54 is formed with two longitudinal partitions 62, $3, radially extending from its periphery to the peripheral outline defined by hub 54 of plate 58'and springs 60. Although the fluid within chamber 51 could be air, it is preferable to fill said chamber with some heavy liquid, such as oil or glycerine.

By virtue of this construction, when gate 48 is forced open by the weight of the material contained in chamber It, virtually no resistance is offered to its movement by plate 58. When the material has been entirely discharged through outlet 43 and counterweight 49 tends to return the 'gate to its closed position, its return movement will be delayed by plate 58, since when said plate is rotated in a counterclockwise direction the fluid is forced to pass through small open- In this case plate 58 will act as a fluid brake and will cause the return movement of gate 48 to take place slowly, in order to make sure that the material has been entirely discharged from chamber l6 before the gate again reaches its closed position, so that clinkers or other obstructions cannot block the full closure of the gate. l

The arrangement just described is operated in exactly the same manner as that shown in Fig. 1, that is, by creating a continuous suction within chamber l3 andintermittently creating a suction also in chamber l6; butwhereas in the device of Fig. 1, atmospheric pressure is the agent of the material is assured by the use of a delaying device in connection with said counterweight.

The apparatus shown in Fig.7 is similar to that of Figfl, and may be equipped with gates both operable 'by atmospheric pressure, such as shown in Fig."1, or else the lower gate 48 can be of the counterweight operated type just described, as shown." :The difierence betweenthis arrangement and those previously described lies in the fact that the duct 55* leading to the lower chamber I6 does not-connect with exhaust pipe 22 but connects chamber l6 to'chamber l3, so that the two chambers are connected in series instead of being connected in parallel; the operation, however, is the same as previously described.

The apparatus shown in Fig. 8 is also in some respects similar to that shown'in Fig. 1, and in the same-the lower gate may be of the atmospheric pressure operated type or else of the counterweight operated type, such as shown at 48'. The duct 66 leading to the lower chamber 16 connects also in this case with exhaust pipe 22, but the damper arrangement is different in that an additional damper 61 is provided through exhaust pipe 22, said damper being operated simultaneously with damper 26' of duct 65 and being in its open position when damper 26' is in its closed position and vice versa. The result will be that when the actuator operates damper 26 to create a suction within lower chamber 16 it will at the same time close exhaust pipe 22, so'that the two chambers will again be connected in series but through the outlet 31' of the upper chamber. 7

From the foregoing it is seen that a continuous operation of the exhauster can be maintained although the material will be discharged from the receiver at regular intervals and a complete discharge thereof is assured every time.

It is obvious that the constructional details of my invention can vary from those shown without departing from the inventive idea. For instance, the closure members for the discharge outlets of the chambers need not necessarily be pivotally mounted so long as they are mounted so as to be movable from the open to the closed position and vice versa and so as to be responsive to atmospheric pressure, or to such controls as may be provided for their operation. I

The drawings should, therefore, be understood as being intended for illustrative purposes only and not in a limiting sense.

I claim:

1. In a suction conveying system, an upper receiving chamber, a lower auxiliary chamber, said receiving chamber having an opening discharging into said auxiliary chamber, said auxiliary chamber having a discharge outlet, a pivotally mounted. closure member adjacent to, and controlling said opening, a pivotally mounted closure member adjacent to and controlling said discharge outlet,'means urging said second mentioned closure member to its closed position,

- means tending to delay the movement'of said second mentioned closure member to its closed position wher by the material contained in said lower chamber will be discharged therefrom in its entirety before said second mentioned closure member will have reached itsv closed position, a.

conveying conduit discharging into said receiving chamber, means for creating a suction within said receiving chamber and conveying conduit, thereby causing atmospheric pressure to move said first mentioned closure member to and to hold it in its closed position, and means for at times connecting said auxiliary chamber to said suction means, thereby allowing said first mentioned closure member to swing to its open position, the Weight of the material consequently discharged from said receiving into said auxiliary chamber forcing said second mentioned closure member to its open position.

2. In a suction conveying system, an upper receiving chamber, a lower auxiliary chamber, said receiving chamber having an opening discharging into said auxiliary chamber, said auxiliary chamber having a discharge outlet, a pivotally mounted closure member adjacent to, and controlling said opening, a closure member controlling said discharge outlet, a conveying conduit discharging into said receiving chamber, means for creating a suction within said receiving chamber and conveying conduit, thereby causing erate the same, and a timing device controlling the operation of said actuator to intermittently open said valve and close said vent closure, so as to equalize the pressure within said two chambers, thereby allowing said first mentioned closure member to swing to its open position.

ARTHUR M. PERRIN,

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