US 3161442 A
Description (OCR text may contain errors)
Dei: ..1 5,1964 q 'FQAREED 3,161,442
TRANSMISSION OF' GRANULAR MATERIAL Filed April 18, 1962 F I m i mmvron 444 V Fe/m/K A. R550 14 770R/VEV5.
United States Patent 3,161,442 TRANSMISSIQN 0F GRANULAR MATERIAL Frank A. Reed, 1009 N. Raymond Ave, Pasadena, Calif. Filed Apr. 18, 1962, Ser. No. 188,396 12 Claims. (Cl. 302-49) This invention relates to a pickup and transmission device for conveying granular material.
Granular material, which term includes the range extending from dusts through gravel sizes, is frequently conveyed through hose by being entrained in an air stream. A familiar example of such a technique is found in pneumatic concrete construction, wherein an intimate mixture of sand and cement is pumped dry or slightly damp through a hose to a nozzle. Just before the mixture leaves the nozzle, water is injected into the stream, and the mixture of water and the entrained granular material is sprayed from the nozzle against a form to constitute a structure. Other typical uses for fluid conveying of granular material include the handling of food stuffs such as flour, granular refractory materials in foundries, and blowing sand into remote'cavities such as old sewers to fill them up.
Mechanisms for picking up and transmitting granular material have been known in the past, but, in general, they have suffered from fluctuation in rates of flow and in occasional unreliability in picking up the material at all. Particularly when it is considered that the product discharged from the nozzle is often an ultimate material of construction whose properties depend on proportions, and that the proportionality is at least in part dependent upon the rate of flow of granular material, it becomes evident that a means for providing a reliable, substantially constant flow of granular material is of con siderable importance. It is not surprising that numerous attempts have been made to provide mechanisms effective for this purpose, including such devices as star wheels whose pocket size and rate of rotation determine the rate at which the granular material is supplied. Theoretically, star wheel type devices should be ideal for this type of mechanism, but have not been particularly successful, because reliable means for getting the material entrained have not existed. Common pneumatic concrete rigs usually employ seven to ten men to keep the device in operation, keep it provided with raw material, and to distribute the end product, and much of their effort is directed toward meeting the steady flow or constant proportioning requirements. This device can accomplish the same results with at least two fewer men, and costs only .on the order of about one-fourth as much to purchase.
It is an object of this invention to provide a pickup and transmission device which requires little or no care or adjustment, and which still provides a sensibly constant, reliable and properly proportioned flow of granular material.
A pickup and transmission device according to this invention includes a hopper having an upPBr and a lower opening. A feed rotor is provided which has a central axis of rotation, together with a face, portions of which move into and out of registration with the lower opening of the hopper as the rotor rotates.
A plurality of non-interconnecting chambers is disposed in the feed rotor beneath the face. A first and a second set of ports are disposed in the plate, one port of each set communicating with each chamber, so that each chamber is connected to a pair of ports, one belonging to each set. At least one of the sets ofports is so disposed and arranged that its members pass sequentially across the lower opening to receive material from the hopper, whereupon the material will flow into the respective chambers.
An expulsion station is included in the device which comprises an inlet conduit and an outlet conduit, the inlet conduit being adapted to be connected to a source of fluid under pressure, such as air, although other gases, or even liquids could be used, depending on the nature and purpose of the material being transported. The outlet conduit is adapted to receive and transmit granular material entrained by the said fluid. The inlet conduit is so disposed and arranged as to register with successive ones of one of the sets of ports, and the outlet conduit is so disposed and arranged as to register with successive ones of the other set of ports. Therefore, upon rotation of the feed rotor, ports of at least one set pass across the lower opening to receive granular material, and whereupon both sets of ports pass to the expulsion station where one member of each pair corresponding to each respective chamber successively registers with the inlet and outlet conduit so as to cause expulsion of the granular material from the respective chambers.
According to a preferred but optional feature of the invention, each chamber includes a depending battle which reduces the chamber to a substantially U-shaped configuration between the ports whereby a continuous and unbroken fluid conduit is formed between the inlet and outlet conduits so that the stream is smooth and continuous between inlet and outlet.
The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings in which:
FIG. 1 is a side elevation, partly in cross-section and partly in schematic notation, showing the presently preferred embodiment of the invention;
FIG. 2 is a cross-section taken at line 2-2 of FIG. 1;
FIG. 3 is a cross-section taken at line 3-3 of FIG. 2;
FIG. 4 is a plan view of a portion of FIG. 1;
FIG. 5 is a cross-section taken at line 55 of FIG. 1;
FIG. 6 is a cross-section taken at line 6-6 of FIG. 4; and
FIG. 7 is a side elevation of a portion of FIG. 1.
The presently preferred embodiment of a pickup and transmission device 10 according to the invention is shown in FIG. 1. It includes a hopper 11 having an upper opening 12 and a lower opening 13. A screen (not shown) may be placed across the upper opening, if desired, to keep out undesirably large rock and the like.
To the inside wall of the hopper, there are aflixed stationary agitator blades 14, which serve to co-act with agitator blades 15 mounted on a rotary shaft 16 so as to mix the material, and to encourage it to pass downward through the hopper to the feed rotor. The shaft passes through a bearing 17 in a base 18. It is keyed to a gear train 19 driven by a fluid motor 20. Other types of motors may be used instead, such as electric or internal-combusti0n motors. Even a power take-off from another source is within the meaning of the term motor as used herein.
The motor is controlled by a valve 21. which receives a sliding seal between the feed rotor and hopper wall to exclude granular material from the region beneath the feed rotor.
A housing 32 extends approximately 45 around the bottom periphery of the lower opening to blank 01f and shroud certain portions of an expulsion station 33. Granular material contained in the hopper is able to come intocontact with face 31 over approximately 315 of the face of the feed rotor.
The feed rotor is shown in full detail in FIGS. 2 and 3. As can best be seen in PIG. 2, a first set of ports 34 is disposed in a circular array. A second set of ports 35 is also disposed in a circular array, but is disposed radially outward of the members of the first set of ports.
As examples of all of the ports, ports 36 and 37 are members of the first and second sets, respectively, and they are radially disposed outward of each other, subtending substantially equal angles around the central axis 38 of the feed rotor, and therefore of the shaft 16.
A plurality of chambers 39 is formed inside the feed rotor. Each chamber is substantially an upright U-shaped member formed by a round bottom 40 with a battle 41 extending downwardly into the chamber, thereby providing a substantially smooth and continuous conduit between the respective ports of the first and second sets relating to each individual ones of the chambers. In practice, the bafile is substantially a cylindrical member interrupted by radially-extending walls, such as wall 42. Each chamber is connected to a pair of ports, one belonging to each of the sets.
An orifice plate 43, which forms substantially 45 of arc, is fitted within housing 32 and held in place by screws 44 (see FIG. 7) through a hose base plate 44a. The orifice plate includes an inlet conduit 45 and an outlet conduit 46. The inlet conduit is radially spaced from axis 38 by about the same distance as the members of the first set of ports, and the outlet conduit by about the distance of the second set of ports. Their angular subtense is about equal to that of the respective ports which they overlap, and the thickness of the walls 42 adjacent to them is slightly less, so that the conduits can overlap a complete one of the ports in some positions, and can overlap respective adjacent pair of ports in others.
The pulsational effecton the overall granular material fiow is reduced by the aforesaid overlap, whereby as one chamber is substantially evacuated, the next full chamber begins to be brought into registration 'and its material removed. The orifice plate overlaps the face radially inwardly and outwardly of the sets of ports, as well as between the sets and their respective members.
Screws 44 are tightened down to eliminate clearance between the orifice plate and the face. This causes a rubbing surface contact to occur between the rotor face and the rubber facing 47 on the orifice plate, which contact forms a seal around all of the orifices and the ports covered by said plate, thereby confining air flow to the chambers whose ports are in register with the orifices, and eliminating fluid loss which would otherwise occur between the orifice plate and the rotor face. In addition to acting as a seal, the rubber facing is eflective in withstanding the wear of granular material which impinges upon it.
To the hose base plate, and passing therethrough, there are fixed an inlet hose 48 and outlet hose 49 which respectively register with conduits 45 and 46. Inlet valve 50 is connected in hose 48. Hose 49 is connected to a nozzle (not shown) at which water may be mixed in pneumatic concrete work, or the hose may simply deliver the material to some destination. The term hose is not limited to flexible conduits. Permanent or semipermanent rigid conduit is, in fact, preferred for some uses.
As can best be seen in FIG. 4, the conduits immediately adjacent to face 31 are shaped substantially like the ports on the feed rotor.
The operation of this device will now be explained. The hopper is filled in FIG. 1 by loading granular material in the upper opening. The motor is turned on by opening valve 21, and the shaft and the feed rotor are therefore turned. Until valve 50 is opened, nothing happens other than that the chambers are filled, and the excess material is, of course, scraped off by the orifice plate and held in the hopper. When a supply of material is desired from the outlet hose, then inlet valve 50 is opened, and fluid, one example of which is air, flows through inlet conduit 45 and into such port or ports of the first set of ports as may be in registration therewith. This entrains the granular material which may be contained in the respective chamber and blows it out through the port or ports of the second set of ports which may then be in registration with the outlet conduit, and thence through the outlet conduit to the outlet hose. It will be seen that this is a smooth sweeping action and that the battle in the middle of the chamber, by reducing the chamber to a smooth uninterrupted passage, avoids eddying flow of the granular materials which might keep the material in the chambers. Therefore, the material is reliably expelled from the respective ones of the chambers.
In the preferred embodiment of the invention, both sets of ports fall into registration with the lower opening of the hopper, and this causes the chambers to be more reliably filled with granular material through both sets. If preferred, only one set of ports or ditferent members of each set of the ports, could come into registration with said lower opening. However, optimum filling of the chambers is assured by permitting both sets of ports to come into registration with the lower opening as shown.
The orifice plate overlays several radial sets of ports so that there is never a time when the ports connected to the inlet and outlet conduits are also exposed to atmosphere.
Pulsations may be limited by enlarging the extent of overlap of the inlet and outlet conduits with the members of the sets of ports so that the time during which minimum registration occurs is held to a minimum.
The device is rugged, simple and reliable. Its first cost and maintenance cost are much lower than those of conventional devices, and it operates with at least two fewer men to accomplish the same results as conventional devices. In fact, it can be used in an unconventional manner not suited for conventional devices, such as using ready-mixed semi-dry concrete, and eliminate even more men. Practically the only points of maintenance are the orifice plate rubber facing, and the face of the feed rotor. Both are easily and economically serviced.
This invention is not to be limited by the embodiment shown in the drawings and described in the description which is given by way of example and not of limitation, but only in accordance with the scope of the appended claims.
1. A pickup and transmission device for granular mate rial comprising: a hopper having an upper and a lower opening; a feed rotor having a substantially vertical central axis of rotation; a face on said feed rotor, which is a substantially continuous, upwardly facing, surface of revolution around said axis, portions of which face are adapted to be moved into and out of registration with the lower opening by turning the feed rotor on its axis; a plurality of non-interconnecting chambers inside said feed rotor and disposed beneath said face; a first and a second set of upwardly facing ports in said face, said sets of ports being disposed in circular patterns in said surface of revolution around said axis, the first set being disposed within the second set, one member of each set being connected to each respective one of said chambers; said ports being so disposed and arranged that one member of each of said pairs will pass sequentially beneath said lower opening to receive material from the hopper as the feed rotor is rotated, whereupon material flows into the respective chambers through both ports; an expulsion station comprising an inlet conduit and an outlet conduit, the inlet conduit being adapted to be connected to a source of fluid under pressure, and the outlet conduit being adapted to receive and transmit granular material entrained by fluid from the inlet conduit, the inlet conduit being so disposed and arranged as to register with successive ones of one of the sets of ports, and the outlet conduit being so disposed and arranged as to register with successive ones of the other of sets of ports, whereby upon rotation of the feed rotor, ports of said sets pass across the lower opening to receive granular material, and whereupon the ports pass to the expulsion station where one member of each set corresponding to each respective chamber sequentially registers with the inlet and outlet conduits to cause expulsion of the granular material from the respective chamber.
2. Apparatus according to claim 1 in which each chamber comprises a substantially elongated region.
3. Apparatus according to claim 1 in which each chamber comprises an upright U-shaped region, whereby pressurized fluid from the inlet conduit expels material from the chamber in a substantially continuous sweep.
4. Apparatus according to claim 1 in which a baflle extends downwardly into the chamber between'the ports whereby to provide a substantially U-shaped chamber between the ports.
5. Apparatus according to claim 4 in which the bottom of the chamber is curved, whereby a substantially smooth and continuous channel is formed between the ports in each chamber.
6. Apparatus according to claim 5 in which the feed rotor is mounted to a shaft, which shaft projects into the hopper, and in which a plurality of agitator blades is attached to the shaft, whereby to' agitate the material in the hopper.
7. Apparatus according to claim 6 in which a motor is provided to rotate the feed rotor and the shaft.
8. Apparatus according to claim 1 in which the expulsion station includes an orifice plate disposed in sliding adjacency to the said face and in which the said inlet conduits and outlet conduits pass through the orifice plate whereby the orifice plate provides a fluid seal between the inlet and outlet conduits and the feed rotor.
9. Apparatus according to claim 8 in which the orifice plate includes a resilient facing adjacent to the feed rotor.
10. Apparatus according to claim 8 in which a housing projects into said hopper and extends partially over thefeed rotor whereby to isolate the orifice plate from the hopper.
11. Apparatus according to claim 9 in which the portion of said face bearing the surface of revolution is planar and in which the said resilient facing is planar opposite said surface of revolution.
12. Apparatus according to claim 11 in which each chamber comprises an upright U-shaped region formed by abaflle extending downwardly into the chamber between the ports to provide a substantially U-shaped chamber of substantially continuous cross-sectional area between the ports.
References Cited in the file of this patent UNITED STATES PATENTS 2,285,216 Lundgren June 2, 1942 2,614,891 Colburn Oct. 21, 1952 FOREIGN PATENTS 1,089,327 Germany Sept. 15, 1960