Two-cylinder pump,especially for transport of concrete

BACKGROUND OF THE INVENTION The invention relates to a two-cylinder pump, in particular for conveying concrete from a pre-filling tank with two orifices leading to conveyor rollers in front of which a driven one-end manifold is rotated, sealed by a rigid support plate and axially arranged, preferably adjustable wear ring.

In such pumps, which are generally used for slurry, but in practice mainly for the conveying of concrete, the conveyed concrete from the pre-filling tank enters one of the conveyor cylinders, while the other conveyor cylinder, filled in the previous stroke, discharges its contents through the distribution pipe. lines connected to the pre-filling tank.

The actuator serves to supply the movement energy necessary for rotational movement of the distributor tube in a manner corresponding to the existing pump strokes. The end of the distributor tube on the conveyor cylinder side must be sealed in order to prevent the flow of particularly liquid and fine-grained components of the conveyed material between the cylinder bore and the distributor tube at the pressure strokes of the conveyor rollers. When transporting concrete, there is, among other things, the danger that the concrete will scour. On the one hand, the seals must withstand the considerable pressures resulting from the considerable heights to which they are transported by the concrete and for which modern concrete pumps must be equipped. On the other hand, the seal must be able to compensate for the wear that occurs between the movable and fixed parts of the seal.

It is known to incorporate a wear ring for each orifice of the transport roller and to arrange the spindle drive shaft with an axial adjustment so that the end of the spreader tube facing the conveyor roller is allowed to slide between the wear rings and the support plate openings in the precoat tank. filling (DT - AS 2104191). While, in this known device, the guide tube drive shaft is adjustable by means of a screw-on nut, an additional, already known device of this kind can also be provided with an additional thrust bolt which acts between the meizi guide tube and the rocker lever (DT-OS 23 62). 670).

Furthermore, it is known to provide a wear ring at the end of the distributor tube on the conveyor cylinder side with a slight axial displacement and to leave a hollow groove between the end of the distributor tube and the ring in which the hydrostatic pressure of the conveyed medium acts both on one end of the ring and on the front side of the distributor. tubing. In this way, the ring of the manifold itself is supposed to be operative, i.e. by means of hydrostatic pressure in a manner. adequate wear,. pushed onto the backing plate and subsequently adjusted (Zeitschrift Baumaschinen-Dienst, workbook 5, May 1976, p. 234).

Practical experience with gaskets of this kind shows that concrete pumps so equipped do not function satisfactorily. On the one hand, the wear is uneven, if the sections of the tracks which the different components perform when the guide tube is rotated differ considerably from one another. Therefore, in these cases, wear occurs with increasing distance from the rotating shaft. This uneven wear will occur after a relatively short period of operation as the effort is as great as possible. reducing the distance between the axis of rotation and the holes in the cylinders. However, the wear cannot be perfectly compensated by axial adjustment of the wear ring. In addition, the manifold is deflected from the plane of the support plate by the hydrostatic pressure of the conveyed medium due to the elastic deformation of the pipe body and / or its bearing relative to the necessary clearance in the bearings of the manifold. This results in a gap which increases in the sealing areas further away from the drive shaft. If, on the other hand, the task of pressing the wear ring is only to maintain hydrostatic pressure, the wear ring can easily be lifted away from the backing plate by penetrating sand or foreign bodies between the two parts, especially at lower transport resistance, resulting in jamming of the guide tube.

SUMMARY OF THE INVENTION It is an object of the present invention to design a sealing end of a distributor tube on the conveyor cylinder side so that sealing caused by deformations and displacements due to hydrostatic pressure can no longer deteriorate, and that uneven wear in terms of wear a pump which, as usual, has a relatively small distance between the rotating shaft and the cylinder bores.

According to the invention, this object is solved. by abrasive. the ring is mounted on a thrust device formed by a fork lever mounted on the fork. rotary shafts non - rotatably connected to the drive lever,. as well as the nut and shaft end, wherein the end of the guide tube and the wear ring are movable relative to one another and sealed to one another.

By engaging the wear ring with a pressurizing device not influenced by the guide tube and the end of the guide tube facing the conveyor cylinder is sealed relatively movably relative to the wear ring, it is obtained. the assumption that movements of the manifold, which cannot be prevented under the action of hydrostatic delivery pressure, do not adversely affect the tightness of the metal seal between the cylinder openings and the wear. ring. Moving. on the other hand, the bearing of the guide tube end in the wear ring permits rotational movement of the wear ring even against the pipe end, which allows wear of the wear ring on the support plate even with uneven wear. For example, by the known axial adjustment of the rotary shaft, it is possible under these conditions to allow the wear ring to abut its entire circumference on the backing plate, since the wear ring rotates accordingly and thus allows. all-round compensation for different wear. The sealing of the pipe end and the wear ring is without problems.

The advantages obtainable by the invention are, in particular, that even at considerable heights to which the medium is conveyed and corresponding pressures, absolutely tight connections of the manifold to the openings, cylinders are achieved, and that, if appropriate, using known adjusting devices or adjusting devices. arrangement to compensate for uneven wear and prevent it. there were no additional gaps in the seal that lead to leaks.

According to a further feature of the invention, the fork lever mounted on the rotary shaft is a driving element for rotational movement of the guide tube.

Another feature of the invention is that the wear ring is rotatably mounted.

The bearing pins are preferably used for rotatably mounting the wear ring, through which the axis of rotation of the wear ring extends, and for the bearing pins bearing bushes are provided in the fork lever, the lever constituting the connection with the rotating shaft.

In another embodiment of the invention, the bearing pins are arranged on a guide ring in which the end of the tube is axially movably and rotatably mounted and sealed, the wear ring resting against the guide ring.

The invention is further characterized in that a bearing arrangement consisting of concave segments and concave segments is used to rotate the wear ring.

Another feature of the invention is that the convex segments are arranged on the guide ring and the concave segments on the fork arms.

In a preferred embodiment of the invention, the wear ring is mounted in the end of the pipe.

According to another. In accordance with an aspect of the invention, the pump is provided with a frame which is adjustable in relation to the support plate and serves to guide the guide ring and the wear ring.

Finally, the last feature of the invention is that adjusting screws are used to adjust the frame relative to the support plate.

The details, further features and other advantages of the invention will appear from the following description of several embodiments of the invention in conjunction with the drawings, in which:

Giant. 1 shows a preferred embodiment of the invention in partial longitudinal section, FIG. 2 shows the object according to FIG. 1 in front view and partly in cross-section.

Fig. 3 schematically and omitting all components not necessary for understanding, sealing after incurred and balanced wear in the representation corresponding to Fig. 1, Fig. 4, a plan view of the object according to Fig. 3, the bearing being reproduced partially in section, Fig. 5 6 shows an object of the invention with another embodiment of the distribution pipe; FIG. 7 Fig. 8 is a front elevational view and cross-sectional view of Fig. 2; Fig. 9 shows a modified embodiment of the present invention in Fig. 3; FIG. 10 shows a modified embodiment of the invention in the representation corresponding to FIG. 9, FIG. 11 a modified embodiment of the invention in the representation corresponding to FIG. 3, FIG. 12 3 shows a modified embodiment of the invention in the representation corresponding to FIG. 3, and FIG. 13 is modified from FIG. 5 with respect to the wear ring bearing.

In the figures, the same reference numerals designate corresponding parts.

In FIG. 1, one of the two conveyor rollers is partially shown and designated 1. In the conveyor roll 1, the piston 2 is moved with the piston rod 3 so that when the piston 2 is returned, concrete is sucked from the pre-filling tank , and as the piston moves forward, the concrete may be forced out of the cylinder 1. The pre-filling tank 4 has two orifices 5, resp. 6 as shown in FIG. 2. According to the illustrated embodiment, the pre-filling tank has a filling funnel 7 and, in its lowest part, a closable opening with a lid 8. Both openings 5 ​​and 6 are alternately connected to the end of the pre-filling tubing 9 cylinders.

For this purpose, the distribution of the concrete is carried out by means of a S-shaped distribution pipe 10, the end 11 of which is associated with the guide 9, is rotatably supported and sealed. For this purpose, this end is welded to the hollow cylinder 12 which is inserted into the neck 14 screwed onto the lower part 13 and supported by the ring 14a. In addition, a gasket 15 is used. The end of the pipe 9 is fastened to this distributor pipe support by means of a neck 16 and a correspondingly formed gasket 17.

The end on the cylinder side is indicated by 22 and is realized by a hollow body welded to the distributor tube 10.

The hollow body has two cams 18 and 18, respectively, for entrainment. 19, mutually offset by

180 °, which together with the slots 20, respectively. 21 provide a movable bearing of the pipe end 22 in the guide ring 23. In the guide ring 23, the pipe end 22 is additionally sealed by means of a sealing ring 24.

The front side of the guide ring 23 carries a wear ring 26, which rests on one side on the front side of the guide ring 23 and on the other side on the support plate 27. By having the guide ring 23 comprises two pivot pins 28 and 28, respectively. 29, offset by 180 °, the wear ring 26 can also be rotated to abut the support plate 27 irrespective of the amount of wear on its circumference. For this purpose, the pivot pins 28 and 29 are mounted in the rotary bearings 30 and 29, respectively. 31 a fork lever 32, which is secured by means of an eye at the end of the rotating shaft 33 on the side of the pre-filling tank. The rotary shaft is connected via a wedge-groove connection 34 to a drive lever 35 which performs a reciprocating movement by means of a motor 36, not shown in greater detail.

The support plate 27 abuts against the reinforced wall 39 of the pre-filling tank, which is provided with a recess for connecting the fastener 40 leading to the respective transport rollers.

The components occupy the relative position initially shown in Figures 1, 2 and 4. However, as soon as wear occurs, the seal must be subsequently adjusted. According to the illustrated embodiment, a nut 42 is provided for this purpose, which is screwed onto the outer end 44 of the rotary shaft. By tightening the nut 42, the rotary shaft can be moved axially and the guide ring 23 and thus the wear ring are co-mounted by means of the pivot lever 32 through the journal bearing 28 to 31. Since the bearing ring makes it possible to pivot the guide ring 23 together with the wear ring 26 around the pivot axis, the plane of the wear ring 26 can be changed from the plane of the backing plate 27. This makes it possible to compensate for the increased wear resulting from the illustrated example. at the lower end of the wear ring, even if the pipe end 22 retains its original position or position. it rotates under the influence of hydrostatic pressure in the opposite direction. The illustrated mechanical post-adjustment by means of the nut 42 can of course also be automated by hydraulic tensioning cylinders or flexible tensioning elements.

In the embodiment according to FIG. 5, the shape of the guide tube is mainly changed from S-shaped to U-shaped. In this way, the hydrostatic forces acting on the U-shaped distribution pipe 10 are compensated. The other components correspond to the arrangement shown in connection with FIG. 1 to 4 and explained above. Only the post-adjustment device is omitted.

The embodiment according to FIG. 6 differs from the embodiment. 1 to 4 essentially in that an S-shaped distribution pipe 10 is also used, but which is not arranged lying, but standing in the pre-filling tank. Therefore, the connection 40 is made sharper than 90 °.

In the embodiment of FIG. 7, the arrangement used to seal the end of the rotary tube 10 on the conveyor cylinder side is altered from the embodiments of FIGS. 1 to 6. Here, the guide ring 23 rests in the frame 50 but bears on its front end. The drawing shown in FIG. 7 is based on the occurrence of uneven wear and corresponds to that shown in FIG. 3.

As can be seen in FIG. 8, in the embodiment shown in FIG. 7, the frame 50 is adjustable by a plurality of adjusting screws 50a and 50d (in a manner corresponding to wear on the support plate shown in FIG. 7). Correspondingly, the guide ring 23 is adjusted relative to the plane of the backing plate and the wear ring 26 can follow uneven wear. On the other hand, the manifold is mounted directly on the rotating shaft. Swivel mounting of the distributor pipe relative to the rotary shaft is not necessary. · Additional adjustment is performed using the adjustment. screws 50a to 50d through frame 50.

The arrangement of the pivot pins according to FIGS. 1 to 8 in the embodiment according to FIGS. 9 and 10 has been altered. The lever 32 has a bearing for this purpose, each consisting of concave segments 56 for convex segments 57 arranged on the guide ring 23. wherein the wear ring 26 is re-arranged on the front side of the guide ring 23.

The embodiment of FIG. 10 differs from the embodiment of FIG. 10 essentially in that the wear ring 26 is arranged inside the end of the rotating tube 10 on the side of the cylinder and sealed by a circular seal 24a which is mounted on the extension 58 of a wear ring 26 in the form of a hollow cylinder and in a groove 59 in the inside of the pipe end 22.

This arrangement has the advantage that, compared to the embodiments according to FIGS. 1 to 9, it has a smaller number of individual parts.

11 and 12 are modified from the embodiments of FIGS. 9 and 10 to the extent that in these cases the concave segments 56 are arranged on the guide ring 23 (FIG. 11) and FIG. on the wear ring 26 instead of at the end of the fork protrusions of the lever 32. Therefore, the convex segments 57 in these embodiments are arranged on the fork arms of the lever 32.

The embodiment of FIG. 13 differs from the embodiment of FIG. 5 essentially in that the guide ring 23 is no longer rotatably mounted in the lever 32, but rather fixed. This results essentially from the relatively greater distance of the rotating shaft from the conveyor rollers 1 and the fact that the uneven wear on the wear ring 26 is therefore negligible, so that the wear ring 26 is able to abut against the support plate on all sides despite the missing structural joints. 27 Mar:

The pipe end 22 is made in the form of a ball in all embodiments of the invention that utilize the pipe end 22 in the guide ring 23. The sealing ring 24 is made of a resilient material.