US3401848A

US3401848A - Apparatus for discharging fluid material from a container

Info

Publication number: US3401848A
Application number: US554848A
Authority: US
Inventors: Kletschke Hans
Original assignee: Kalle GmbH and Co KG
Current assignee: Kalle GmbH and Co KG
Priority date: 1965-06-05
Filing date: 1966-06-02
Publication date: 1968-09-17
Anticipated expiration: 1985-09-17
Also published as: NL6607044A; GB1088348A; BE681990A; DE1542246A1

Description

Se t. 17, 1968 H. KLETSCHKE 3,401,843

APPARATUS FOR DISCHARGING FLUID MATERIAL FROM A CONTAINER Filed June 2, 1966 1 j y M m 2 r J ,2 V j B 777 d 3 i FIG.| 4 1 6 FIG. 3 FIG. 2

INVENTOR. HANS KLETSCHKE aBAaAJZ M ATTO EY United States Patent 5 Claims. (C1,. 222-363) ABSTRACT OF THE DISCLOSURE This invention relates to improvements in apparatus for discharging material in fluid form from a container. By -material in fluid form is meant a fluid or a finely divided solid or a mixture thereof The apparatus comprises a reciprocatable piston, which partially rotates during reciprocation, and which has a recessed portion protruding into a container when the piston is at the top of its stroke and being aligned with an outlet in a cylinder, in which the piston reciprocates, when the piston is at the bottom of its stroke. Material is fed from the container into the recess, and from the recess into the outlet, by the action of pressure prevailing in the container or, in the absence of pressure in the container, by the action of gravity.

Apparatus for the quasi-continuous discharge of gaseous, liquid and/or solid substances from containers is known. With such apparatus a certain amount of the medium which is to be discharged is periodically removed from the container and conveyed as required. The interior of the container may be under a pressure in addition to the gravitational pressure of the contents. The discharge apparatus may have rotary pistons with axial recesses, or pistons which reciprocate in a cylinder.

As compared with a discharge apparatus having rotary pistons, an apparatus with recipricating pistons has the advantage that there is less difiiculty in sealing oif the piston where high pressure differences exist. Furthermore, rotary pistons must be of considerable size when substantial quantities must be discharged, whereas an apparatus with reciprocating pistons is of relatively small size even for a large discharge capacity. Thus, piston slides are known in which the sealing means is an axially movable piston whose control surface upon opening exposes slots in the wall of a cylinder and thus provides a passage. In the case of piston slides, two pistons preferably are arranged one behind the other and the inflow of the medium to be discharged takes place between these pistons. It is a disadvantage of piston slides, particularly when discharging suspensions of solid substances in liquids, that solid matter easily penetrates beneath the pistons and is there compressed. However, constructions are also known in which this detrimental penetration is avoided. In the case of all piston slides and similar constructions there is nevertheless the problem of wear, which particularly occurs to a substantial extent in the case of discharging the above mentioned suspensions of solids in liquids. Moreover, piston slides are unsuitable when substantial pressure differences must be overcome.

The present invention provides an apparatus for discharging material in fluid form from a container, as hereinbefore defined, the apparatus including a piston arranged to reciprocate, with partial rotation, in a cylinder and during part of its stroke to project from the cylinder, the piston having in the part thereof which so projects a recess to receive the material, which recess is arranged to be sealed off on withdrawal of the piston into "ice the cylinder, and also including in the wall of the cylinder an outlet for the material with which the recess can be brought into register. The cylinder is attachable to an outlet of the container in such a manner and the arrangement is such that the piston can project into the container and can execute its stroke while confining the container with respect to the exterior. For use with a container under pressure, the apparatus is made duly pressure-resistant and has a suitable stufling box for the piston. The piston may be arranged, in its stroke, to rotate through Apparatus according to the invention is very reliable in operation and is subject to relatively little wear.

The invention is illustrated by way of example in the accompanying drawing, in which:

FIGURE 1 is an elevation of the relevant part of the apparatus, most of which is shown in section, and

FIGURES 2 and 3 show different forms of the piston of FIGURE 1.

Referring to the drawing, the piston 7 is longer than the cylinder 4, and as shown in FIGURE 1 its upper end has an annular recess 8, which in an upper working position, shown in phantom at A, projects into a container of the type above described, while in a lower working position B it is located with the recess in register with a side outlet 6 of the housing including the cylinder 4. The piston is arranged to execute a rotation of 180 during its movement from the lower to the upper working position and vice versa. The rotary cam stroke movement may be produced by means of a commercially available crank drive, eg of the Milton-Roy design. A crank drive of the Milton-Roy design is shown for example in German Patent No. 1,104,786.

FIGURE 1 also shows the container in the form of a pressure pipe 1 with a rotary shaft 2, to which mixing and conveying arms are shown fixed, from which pipe a medium is to be discharged. The apparatus of the invention is attached to a flanged outlet 3 of the pressure pipe 1. The housing including the cylinder 4, in its lower part carries a stufling box chamber 5 as well as the outlet 6. When the piston 7 is in the upper working position the recess 8 fills with the medium in the pressure space, and when the piston is in the lower working position the medium is discharged through the outlet 6.

Instead of being annular as in FIGURE 1, the recess in the piston can be in the form of a transverse bore as in FIGURE 2 or of a blind hole as in FIGURE 3. The size of the recess should be selected so as to preserve the requisite mechanical strength of the piston, while giving an adequate delivery.

Both the cylinder and the piston of the apparatus of the invention are provided with particularly wear-resistant surfaces, and may consist of steel which has been rendered wear-resistant by nitriding by one of the conventional methods, for example by the Sult-Inuz process or by the so-called mild nitriding process. A seal between the pressure chamber and the discharge chamber may be achieved by accurate grinding of the piston into the housing bore. The use of piston rings is also possible. A seal from the exterior is provided by the above mentioned stuifing box of conventional construction. When it is intended to discharge gases which are under high pressure, the seals must be particularly efiicient.

The pressure difference between the space from which the medium is discharged and the space into which it is transferred can be considerable and may, for example, be several hundred atmospheres. The upper limit of pressure is determined only by the mechanical load-bearing capacity of the material of the parts of the apparatus, and of the material being discharged. Depending on the operating conditions, working periods of at least several hundred hours can be achieved. Working periods of 1000 hours are generally attained, but periods of 1500 hours or more have been reached.

The discharge of incompressible liquid and solid substances from a container by means of the apparatus of the invention is governed solely by gravity acting on the substances. For this reason the maintenance of a particular pressure in the container is in this case not essential. Where gases or liquified gases are to be discharged, the effect of gravity is assisted by the expansion of the gases into space under lower pressure.

The amount of gas, liquid or solid discharged depends on the size of the recess in the piston and on the number of strokes per unit time. It has proved of advantage for the piston to perform to 120 strokes per minute, but higher and lower rates can be used. It is also possible to use the apparatus for sampling purposes, the piston being caused to execute a single stroke as required.

The apparatus of the invention is primarily suited to the emptying of pressure chambers in which reactions take place continuously. It is advantageously used in the case of heterogeneous reactions in which solids suspended in liquids are reacted. The apparatus is particularly suitable for this purpose since in view of the rotation of the piston which is superimposed on the reciprocating movement, particularly advantageous wear characteristics are achieved. This is shown by the particularly effective seal of the piston in the cylinder and by the length of time that it remains adequate. Thus, an output rate of 100 liters per hour has been achieved in discharging a cellulose suspension from a digester at atmospheres gauge pressure, the piston having a cm. recess and executing 24 semi-rotary strokes per minute. The working period of the cylinder was in that case between 1400 and 1800 hours.

A further advantage of the apparatus of the invention is that at each stroke the piston penetrates relatively deeply into the container to be discharged. In the case of suspensions this avoids non-representative removal of the contents, causing undesired separation of the components of a mixture, such as is liable to occur with all other known discharge devices unless auxiliary means such as screws or stirrers are provided to prevent settling out in zones where this is liable to occur. There is also little danger, when apparatus according to the invention has been left connected to a filled digester without being used for a considerable time, that the piston will become seized in the cylinder, because it is possible to bring the piston to the level of the bottom of the vessel and to leave it there. However, in some cases it still may be advantageous to use an auxiliary device with the apparatus of the invention, eg a device which assists the progressive movement of a loose solid material. This can be achieved very simply by mounting a screw on the cylinder.

The discharge apparatus of the invention is relatively inexpensive compared with discharge equipment having rotary screws and of the same output. I

It will be obvious to those skilled in the art that many modifications may be made Within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

What is claimed is:

1. Apparatus for discharging material from a hollow container comprising a cylinder having an open end thereof in communication with the hollow interior of said container, piston means mounted in said cylinder to reciprocate and rotate with respect thereto, said piston means having a solid free outer end fitting within said cylinder to provide a seal therewith, said piston means having recess means formed therein and spaced from said solid free end for receiving material therein, said cylinder having an outlet formed therein, said piston means having a discharge position wherein said recess means is aligned with said outlet, and said solid free outer end of the piston is positioned in sealing engagement with a cylinder portion intermediate said outlet of said cylinder and said open end of said cylinder.

2. An apparatus according to claim 1 in which the piston means rotates through in one stroke thereof.

3. An apparatus according to claim 1 in which the recess means has an annular shape.

4. An apparatus according to claim 1 in which the recess means is a bore through the piston means.

5. An apparatus according to claim 1 in which the recess means is a blind hole in the piston means.

References Cited UNITED STATES PATENTS 2,220,466 11/ 1940 Tamrninga 2.22365 X 2,721,004 10/1955 Schultz 222519 X 2,751,124 6/1956 Jones 222340 X 2,780,984 2/1957 Kleeman 222-404 X 2,847,147 8/1958 Land 222-365 X 3,164,304 1/1965 Jager et al 222-366 X STANLEY H. TOLLBERG, Primary Examiner.