US2077898A - Container for granular and like materials - Google Patents

Description

Apnl 20, 1937. F. ROLFF 9 3 CONTAINER FOR GRANULAR AND LIKE MATERIALS Filed Sept. 15, 1934 Patented Apr. 20, 1 937 UNITED STATES PATENT OFFICE CONTAINER FOR GRANULAR AND LIKE MATERIALS Friedrich Rolif,

Berlin, Germany 6 Claims.

This invention relates to a method of emptying containers for moist or dry granular or pulverulent materials by means of a gaseous pressure agent.

I-Ieretofore the emptying of these containers has been performed either by simply blowing off the material or by expelling or conveying the material by means of compressed air or the like. In the former method an accumulation or bridg- 'ing of the material frequently takes place in front of the outlet, preventing the discharge.

The use of air under pressure is accompanied by the drawback that merely the middle portion of the material is expelled from the container by the air acting on the surface of the material, a

crater thus being formed, through which the air is able to pass to the outlet aperture without moving the material. The material in the container cannot be ejected in this fashion at all, because the air presses the same firmly against the wall of the container. I

It has also already been proposed to break up,

with the assistance of mechanical means which maintain the material in motion, any crater formed by the air, and thus to prevent a clogging of the material in the container. All of these means, however, are inadequate to ensure the emptying of the container in proper fashion.

To overcome these drawbacks the material in the container is subjected, whilst being acted upon by the gaseous pressure agent, to the continuous pressure of a follow-up plate, which directs the pressure agent towards the outer wall of the container. I

The invention is illustrated by way of example in the accompanying drawing, in which- Fig. 1 is a section through the preferred form of embodiment of my invention.

Fig. 2 is a section through two adjacently disposed containers, which may be emptied alternately.

Fig. 3 is a section through the supply and filling container of a sand-blasting apparatus.

Fig. 4 is a section through a modified form of embodiment of a plate pressing against the material.

Fig. 5 is a modification of the drive for the plate.

The method according to the invention may be employed in all cases in which it is desired to remove moist or dry granular or pulverulent material from a container. The same may be used for corn pits or for emptying reservoirs for any kind of material which is at least so dense that the pressure agent does not pass too readily through the intermediate spaces. It is also equally capable of use in connection with casting machines for conveying the sand, or with sandblasting apparatus for conveying the granular sand. It is also useful for blowing machines for filling molds of all kinds.

The method according to the invention is preferably performed as follows:

It is desired to pass material, which is stored in the container I, to the outlet 4 by means of a gaseous pressure agent, preferably air under pressure, which may be introduced into the container I in regulable fashion at 2 by means of a valve 3. In order to prevent the pressure agent, which is compressed to 1 to 6 atm., from merely piercing through the material and, thus forming a crater, a plate 5 is caused to act on the surface of the material, being guided by means of a rod 6 in the detachable top I of the container I. The rod 6 possesses at the upper end a piston 8, which reciprocates within a pressure cylinder 9. The ratio between the diameter of the piston 8 and that of the plate 5 is preferably between 1:5 and 1:3. The piston rod 6 is sealed against the container I by means of a stuffing box II] or the like. In the cylinder 9 a pressure agent may also be introduced in regulable fashion at the upper end through the pipe II and the valve I2. For the purpose of lifting the plate 5 after the emptying of the container a gas under pressure may also be introduced into the cylinder 9 at the lower end through a pipe I I furnished with a regulating valve I3. The valves I2 and I3, in the usual manner, are so arranged that in the closed position they allow the pressure agent to escape from the cylinder 9 for the purpose of being able to move the piston 8 by the pressure agent on the opposite side.

The operation of this arrangement is as follows:

After the container I has been filled with the material, the latter is passed from the container I through the outlet aperture 4 to the points of use. At first there is opened the valve I2, and the piston 8 is placed under pressure. In this manner the plate 5 is pressed against the surface of the material.

Immediately the pipe 2 for the pressure agent is opened the latter enters the container above the plate 5. The plate 5, however, is not in close contact with the container I, and a small annular gap I5 is allowed to remain. In consequence the pressure agent passes through the gap I5, and moves the material below the plate 5 to the outlet. In this connection the plate 5 always requires to rest closely against the material in order to prevent the pressure agent from merely piercing the material. As the container l is emptied by the pressure agent the plate follows the material and presses firmly against the same, immediately closing any craters which may tend to form in the material. Emptying proceeds until the plate 5 reaches the bottom of the container. In the form of embodiment illustrated in the drawing the bottom is slightly conical in form.

When the container l is empty, there is first shut off the supply of pressure agent at 2 by means of the valve 3, the pressure supply through the pipe H to the cylinder 9 also being stopped. The valve 83 is then opened, so that pressure agent entering at this point lifts the piston 8. Immediately the plate 5 has reached its highest position, the container may be filled with material afresh. This may be effected by means of a filling aperture, which is capable of being closed again, or after raising the top I with all parts associated therewith.

The arrangement described above will usually be found sufficient for non-continuous operation. It is fully adequate for the majority of casting machines, such as molding machines and the like, as the material in the container is sufficient for several molds, which require to be filled successively.

If, however, the material is to be employed in continuous operation, the same requires to be fed without a break to the point of use. In this case it is desirable to provide a plurality of containers I (Fig. 2). Each of these possesses the parts described in conjunction with Fig. 1. The outlets 4 are passed to a change-over valve l6, which connects either the one or the other container l with the pipe 1. The valves 3, l2 and I3 of the one container are preferably so connected by levers I8, I9, with those of the other container that the open position of the one valve corresponds with the closed position of the other. These connections may also be employed for merely certain of the valves.

It is also possible to provide for the supply container a filling or sluice container 2|, whichv may be filled during the time when the container l is being emptied, and after the emptying of the latter enables the material therein to be passed rapidly to the container I.

An arrangement of this kind is shown in Fig. 3. On the container 1, which is equippedwith the same auxiliary apparatus as described in connection with Fig. 1, there is mounted the container 2| in such fashion that it surrounds the cylinder 9.

In the top I of the container there are provided one or more apertures 22, which may be closed by conical members 23. Each conical member depends from a rod 24 pivoted to a lever 25. The levers 25 of all conical members 23 are preferably mounted on a shaft 26 traversing the container and capable of being operated by a control device 21 for the purpose of lifting and lowering the conical members 23. A special pipe 28 with valve 29 serves if necessary for the introduction of pressure agent into the container 2| for transferring the material in the same to the container I. The transfer of the material from the container 2! to the container I may be performed subse quent to or during the upward movement of the plate 5. The material is passed through the gap I5 to below the plate 5.

Insead of conducting the pressure agent in direct fashion to the container, the same may also be supplied to the hollow plate 511 through a hollow piston rod 6a. (Fig. 4). In this case the hollow plate 5a possesses passages 30 running obliquely outwards, which passages, however, require to open out above the lower edge of the plate 5a. Since in this case the complete pressure agent is required to pass through the hollow piston rod, and accordingly through the cylinder 9, the piston 8 requires to be so large that it is also in a position to press the plate 5a against the material in the container I.

Instead of the advance movement of the plate 5 by means of the piston 8 through the medium of a pressure agent, any other desired follow-up form of advance may be selected. In place of the piston rod 6 there may be employed, for example, a spindle 3i, the nut 32 of which is operated by an electro-motor 33.

Between the motor 33 and the nut 32 there requires to be connected an adjustable friction clutch 34, or the motor 33 is furnished with a load regulator 35, which disconnects the motor when it is overloaded. The piston 8, instead of being operated by a gas under pressure, may also be operated by a liquid under pressure.

It will be understood that no restriction is made to the particular details of construction and arrangement of the parts illustrated in the drawing, and that numerous modifications are quite possible within the meaning of the above description and the annexed claims without departing from the spirit of the invention.

What I claim as new and desire to secure by Letters Patent is:

1. In a container for granular and like materials adapted to be emptied by a pressure agent, an outlet for the said material located at the bottom of the container, an impeller having a smaller diameter than the said container and pressing against the upper free surface of the said material, means for admitting pressure to the said container above the said impeller, and means for regulating the pressure admitted to the said container.

2. In a container for granular and like materials adapted to be emptied by a pressure agent, an outlet for the said material located at the bottom of the container, an impeller having a smaller diameter than the said container and pressing against the upper free surface of the said material, a cylinder, a piston within the said cylinder to move the said impeller, means for admitting pressure to the said container above the said impeller, and means for regulating the pressure admitted to the said container, the said piston being operated by the pressure agent which serves to discharge the material.

3. In a container for granular and like materials adapted to be emptied by a pressure agent, an outlet for the said material located at the bottom of the container, an impeller having a smaller diameter than the said container and pressing against the upper free surface of the said material, a cylinder, a pressure-actuated piston in the said cylinder to move the said impeller, regulable means for admitting the said pressure agent to the said container above the said impeller, and a regulable means for admitting a pressure agent to the said cylinder below the said piston for the purpose of lifting the impeller when the material has been discharged.

4. In a container for granular and like materials adapted to be emptied by a pressure agent, an outlet for the said material located at the bottom of the said container, an impeller having a smaller diameter than the said container and pressing against the upper free surface of the said material so as to leave exposed the peripheral surface of the material, means for pressing the said impeller continuously against the said free surface, means for admitting pressure to the said container to act on the said peripheral surface, and means for regulating the pressure admitted to the said container.

5. In a container for granular and like materials adapted to be emptied by a pressure agent, an outlet for the said material located at the bottom of the container, an impeller having a smaller diameter than the said container and pressing against the upper free surface of the said material, a cylinder, a piston within the said cylinder to move the said impeller and acted upon by the said pressure agent, means for admitting pressure agent to the said container above the said impeller, and means for regulating the pressure admitted to the said container, the ratio between the diameter of the said piston and the diameter of the said impeller being between 1:5 and 1:3.

6. In a container for granular and like materials adapted to be emptied by a pressure agent, an outlet for the said material located at the bottom of the container, a plate having a smaller diameter than the inner diameter of the said container and pressing against the upper free surface of the said material so as to leave exposed a certain portion of the surface of the material about the periphery, a cylinder, a piston within the said cylinder to move the said plate and acted upon by a gaseous pressure agent, a valve-regulated feed pipe for supplying a gaseous pressure agent to the said container to act upon the said exposed surface of the material, and a valveregulated feed pipe for supplying a gaseous pressure agent below the said piston for the purpose of lifting the saidplate when the material has been discharged from the container.

FRIEDRICH ROLFF.

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