US2084764A - Conveying bulk materials - Google Patents

Description

June 7- E. J. 1.. CONSTANTIN ,08 ,764

CONVEYING BULK MATERIALS Filed Manch 21, 1956 l\ M, INVENTOR b E. J. L. F. (0N5TANT/N Q Z ZI EM ZM ATTORNEY Patented June 22, 1937 UNITED STATES CONVEYING BULK MATERIALS Eusebe J. L. F. Constantin, Paris, France, assignor to Fuller Company, a corporation of Delaware Application March 21, 1936, Serial No. 70,010. In France March 29, 1935 9 Claims.

This invention relates to a method and apparatus for conveying bulk materials pneumatically, and is more particularly concerned with the handling of fragile and unctuous materials.

Examples of materials having either or both-of these characteristics are soap, in the form of chips, flakes and beads; cereals in flake form; malt; some grains and seeds, and soda ash.

Previous types of pneumatic conveyors damage such materials and render them unfit for use, by breaking substantial quantities of the individual pieces or particles and, if the material is unctuous, by forming masses or agglomerates.

Thus, soap flakes are broken by mechanical shearing, compression and impact at high velocity against elements of the feeding apparatus and the transport pipe-line and even moderate compression causes the flakes to form agglomerates which fail to disperse in water and therefore are unsatisfactory to many users. Soft crystals, such as soda ash, are partially pulverized both by compression and high velocity conveying.

It is, accordingly, the primary purpose of the invention to obtain the economies and convenience of pneumatic conveying withoutdamage to materials of the classes described. To this end, the apparatus is so designed and operated that the material conveyed is subjected to a minimum of shear, compression and impact forces, and the conveying air velocity is preferably so controlled that it will not substantially exceed the minimum necessary to force the material to the point of delivery.

For a better understanding of the invention, reference is made to the accompanying drawing, in which:

Fig. 1 is a front elevation, partly in section, and

Fig. 2 is a sectional elevation of the apparatus.

Referring to the drawing, the apparatus will be seen to comprise a casing having vertical side walls I and 2, and steeply inclined end walls 3 and 8, the walls terminating in a flange 5, surrounding the inlet of the casing, for connection to a storage bin or other source of material supply. The walls I and 2 are joined at their lower ends by a web 6 to form a, support for the apparatus, and the end walls terminate in a hollow cylindrical stator casing l, which surrounds preferably a little more than threequarters of the circumference of the feed roll 8. The stator casing is preferably lined with a renewable liner comprising two sections 9 and 55 it, of hardened steel or other suitable wear resisting material, suitably secured to the casing, as at ll. Liners ID of various widths, and ex tending beyond the edge l2 of the casing wall 4, may be substituted to limit the effective size of the inlet, whereby freely flowing materials 5 will not be packed in the cells to be described more fully hereinafter.

The side walls I and 2 are provided with circular openings to admit the feed roll 8, the openings having diameters slightly greater than the diameter of the feed roll, the clearance being preferably the minimum which will avoid actual metal-to-metal contact. These openings are closed by circular end plates l3 and I4 and which are provided with annular recesses as indicated at IE to form flanges which may be secured in the usual manner to similar surfaces on the walls I and 2 surrounding the openings. The side plates l3 and M are chambered to accommodate the bearings 16 for the shaft 11 of the feed roll 8.

The feed roll is provided with a plurality of cells or pockets I8, each having a steeply inclined rear wall l9 and a forwardly inclined front wall 20. The rear wall is provided with a relatively sharp and forwardly directed leading edge 2|, which is preferably formed as a part of a separate and renewable piece secured to the wall l9.

Preferably slightly beyond the center line of the feed roll 8, the stator casing l and the liner 9 are provided with a narrow slot 22, the slot 0 having a length approximately equal to the width of the roll 8, as indicated in dotted lines in Fig. 1. This slot forms a discharge orifice and communicates with the top of an ejector 23, the latter having an inclined rear wall 24. The ejector 23 is provided with a flange 25 for connection to the usual pipe-line.

In order that the material will be caused to pass downwardly through the inlet of the casing at a uniform rate and without substantial compression, I have provided as a preferred form of feeding apparatus, endless belts 26 and 21 which may be of any suitable flexible material such as rubberized fabric, and are preferably provided with ribs 28 to engage the material. The supporting and driving means for each conveyor are substantially similar and include a driven roll 29 and an idle roll 30. The roll 29 may be driven through a shaft 3|, pulley 32 and a belt 33 which passes over a pulley 34 which may suitably be secured to the roll shaft 11. Suitable miter gears 35 may be provided to drive a shaft 36, indicated in dotted lines in Fig. 2 to rotate the driven roll of belt 21. The idle rolls 3B are supported for movement toward or away from the m horizontal row of orifices, indicated by the orifice 4|, which communicate with the cells after the rear wall IQ of each cell passes beyond the upper edge of the liner. After a cell passes the orifices 4|, and the latter are sealed by the leading edge 2| of the rear wall, air at a relatively lower pressure is admitted through a second horizontal row of orifices, indicated by the orifice 42, which communicate with a manifold 43. Likewise when the orifices 42 are covered by the leading edge of the cell, the forward wall passes the discharge orifice or slot 22. create the essential velocity for transporting the material through the pipe line is admitted to u the ejector 23 through an orifice 44 which opens into the ejector near the base of the inclined wall 24.

The preferred operation of the apparatus is as follows:

30 The conveyor belts are driven, in the direction of the arrows, at relatively slow speed to cause the material to descend uniformly, withoutsubstantial compression, as described above. The idle rolls are adjusted to a position such that the material in falling will tend to drop into the cells |8 beyond the edges of the stator casing, or more particularly of the liner sections 9 and I0. By moving the idle rolls inwardly, it will be apparent that there will be alesser tendency to shear the material, as between the leading edge 2| and the edge l2 of the wall 4, or its liner Ill. The feeder roll is preferably rotated at unusually high speed, speeds ranging from 200 to 400 R. P. M. being found most satisfactory, the preferred speed being 325 R. P. M. This high speed together with the restricted efiective opening of the inlet of the casing, the position of the conveyor belts 26 and 21, and the shape of the cells causes the material to be withdrawn in relatively small quantities and to accumulate, due to inertia, against the rear walls I9 of the cells. As the cells pass the horizontal center line of the roll 8 the material bears against the liners and'is moved to the discharge orifice by the leading edge 2| of the rear wall of the cell.

Although the relative pressures of the air admitted to the apparatus at the various points referred to above are not critical, I have found that the best results are obtained if the relations are in accordance with the following ratios:

Assuming that the material can be conveyed at a velocity of 50 feet a second and that the backpressure of the transport pipe line is two pounds per square inch, the pressure of air admitted through the orifice 44 should be 4 pounds, that of the manifold 43 should be pounds and that of manifold 40 about pounds per square inch.

.The primary purpose of admitting the air at The additional air necessary to.

material with it. This rapid decrease in pressure. the gentle slope of the inclined wall 24 and the location of the orifice 44 cushions and prevents impact of material against the surfaces of the ejector. As a secondary purpose, a small volume of the airadmitted through the orifices 4| escapes, due to slippage, between the leading edge 2| and the edge. of the casing at I2, thereby blowing away particles which might otherwise be trapped and sheared between these edges.

I claim:

1. The method of conveying bulk materials through a pipe-line pneumatically, which comprises continuously withdrawing separate quantities from a source of supply, charging each quantity with a supply of air at high pressure, maintaining each quantity under a high intermediate pressure relatively to the pressure in the pipeline until the quantity is discharged into the pipe-line by charging it with an additional supplyof air at an intermediate high pressure, discharging the quantities successively into the pipeline, and supplying additional air to the latter at low pressure and in sufficient volume to create the necessary air velocity to force the material to a delivery point. 7

2. The method of conveyingbulk materials through a pipe-line pneumatically, which comprises rapidly and continuously withdrawing separate quantities from a source of supply, advancing the materials and supplying each quantity with a charge of compressed air at high pressure at a point between the source of supply and the pipe-line, maintaining the charge at an intermediate pressure by supplying additional compressed air at a point between the first supply point and the pipe-line, discharging the quan-.

tities successively into the pipe-line, and supplying additional air to the pipe-line at low pressure to create the necessary air velocity to convey the material to a delivery point.

3. The method of conveying bulk materials through a pipe-line pneumatically, which comprises rapidly and continuously withdrawing separate quantities from a source of supply, advancing the materials and supplying each quantity with a charge of compressed air at high pressure admitted at a point between the source of supply and the pipe-line, maintaining the charge at an intermediate high pressure by supplying additional compressed air at a point between the first supply point and the pipe-line, discharging the quantities successively through a narrow orifice into the pipe-line and supplying additional air to the latter at low pressure and of limited volume to convey the ,material at low velocity to a delivery point.

4. The method of conveying fragile bulk materials through a pipe-line pneumatically, which comprises conveying materials from a source of supply at a slow and uniform rate, rapidly and continuously withdrawing separate quantities. sealing each quantity against substantial loss of air pressure and supplying the quantity with a charge of air at high pressure at a point be tween the source of supply and the pipe-line, sealing the quantity from said source of air-supply and maintaining the charge at an intermediate highpressure by supplying additional air at intermediate high pressure at a point between the first supply and the pipe-line, sealing the second source of supply and discharging the quantities successively through a narrow orifice into the pipe-line and conveying the material to a delivery point at low velocity by supplying additional air to the pipe-line at low pressure and limited volume.

5. Apparatus for conveying bull; materials through a pipe-line pneumatically, which comprises the combination of a casing having an inlet for receiving materials from a source of supply and a discharge orifice, a feed roll supported for rotation within the casing between the inlet and discharge orifice and partly surrounded by a wall of the casing, the roll being provided circumferentially with a plurality of cells to withdraw separate quantities of materials and deliver them to the discharge orifice, an ejector communicating with the discharge orifice and provided with a connection for a pipe-line, a connection for supplying high pressure compressed air to the cells at a point between the inlet and discharge orifice where the cells are substantially sealed by the wall of the casing, a second connection for supplying additional air at an intermediate high pressure between the pipe-line and the first connection but sealed from the latter by a wall of a cell and a connection opening into the ejector beyond the discharge orifice for supplying additional air to create the necessary velocity to convey the materials to a delivery point.

6. Apparatus for conveying bulk materials through a pipe-line pneumatically, which comprises the combination of a casing having an inlet for receiving materials from a source of supply and a narrow horizontal discharge orifice, a feed roll supported for rotation within the casing between the inlet and the discharge orifice, ap-

proximately three-quarters of the circumference of the feed roll being surrounded by a wall of the casing, the roll being provided circumferentially with a plurality of cells in sufiicient number to include at least two cells between the wall of the casing at the inlet and the discharge orifice, the cells serving to withdraw separate quantities of material from the inlet and deliver them to said orifice, an ejector communicating with the discharge orifice and provided with a connection for a pipe-line, means to supply air to the apparatus at three points, substantially sealed from each other and the inlet of the casing by walls of the cells, comprising a connection opening into the casing beyond the inlet, a second connection opening into the casing between the first connection and the discharge orifice, and a third connection opening into the ejector beyond the orifice to supply suificient air to create the necessary velocity in the pipe-line to convey the material to a delivery point.

7. Apparatus for conveying bulk materials through a pipe-line pneumatically, which comprises the combination of a casing having an inlet for receiving materials from a source of supply and a discharge orifice, a feed roll supported for rotation within the casing between the inlet and discharge orifice and partly surrounded by a wall of the casing, means within the inlet to prevent arching of the material and to cause it to descend to the feed roll at a uniform rate, the roll being provided circumferentially with a plurality of cells to withdraw separate quantities of materials and deliver them to the discharge orifice, an ejector communicating with the discharge orifice and provided with a connection for a pipe-line, a connection for supplying high pressure compressed air to the cells at a point between the inlet and discharge orifice where the cells are substantially sealed by the wall of the casing, a second connection opening into the ejector beyond the discharge orifice for supplying additional air to create the necessary velocity to convey the materials to a delivery point.

8. Apparatus for conveying bulk materials through a pipe-line pneumatically, which comprises the combination of a casing having an inlet for receiving materials from a source of supply and a discharge orifice, a feed roll supported for rotation within the casing between inlet and discharge orifice and partly surrounded by a wall of the casing, the roll being provided circumferentially with a plurality of cells to withdraw separate quantities of materials and deliver them to the discharge orifice, and an endless belt conveyor adjacent to a wall of the inlet to deliver the material at a uniform rate to the feed roll, rolls to carry the belt, one of the rolls being located adjacent to the feed roll and a sufiicient distance. from the wall of the casing to cause the material to drop into the cells beyond the leading edges thereof and said wall of the casing, an ejector communicating with the discharge orifice and provided with a connection for a pipe-line, and means to supply compressed air to the ejector to create the necessary air velocity to convey the material to a point of delivery.

9. Apparatus for conveying bulk materials through a pipe-line pneumatically, which comprises the combination of a casing having an inlet for receiving materials from a source of supply and a discharge orifice, the end-walls of the inlet being inclined and terminating in a substantially hollow cylindrical stator provided with a discharge orifice, a feed roll supported for rotation within the stator between the inlet and discharge orifice, the roll being provided circu.m

ferentially with plurality of cells to withdraw separate quantities of materials and deliver them to the discharge orifice, endless belt conveyors adjacent to each end-wall of the inlet, the conveyor belts passing over driven rolls near the upper end of the inlet and idle rolls adjacent to the feed roll, the idle rolls 'being adjustable with relation to the end-walls to control the effective opening to the feed roll, an ejector communicating with the discharge orifice and pro vided with a connection for a pipe-line, and a connection for supplying compressed air to the ejector to create the necessary velocity to convey the material to the point of delivery. EUSEBE J. L. F. CONSTANTIN.

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