EP0681672B1 - Process for conveying thick matter containing preshredded scrap metal or similar solids - Google Patents

Abstract

Thick matter and solids are conveyed together and substantially continuously through a conveyor pipeline. The thick matter is forced by a conveyor piston driven by a piston pump from a feed container into a conveyer cylinder. A forward face of the piston has a cutting crown with a cutting edge cooperating with an annular cutting ring to cut off solids projecting beyond an inlet in the conveyer pipeline.

Description

The invention relates to a method for conveying pre-comminuted metal scrap or similar solid materials containing solid materials. The invention further relates to a device for conveying pre-comminuted metal scrap or similar solid materials containing solid materials.

To date, two methods have been used to incinerate special waste delivered in containers, in particular in drums made of sheet metal or plastic, in special waste incineration plants. In the first method, the barrels are introduced without crushing using grippers into a combustion furnace, which is predominantly designed as a rotary kiln, and there they are burned together with their contents at high temperatures. However, this leads to intermittent fluctuations in the combustion temperature, the amount of exhaust gas and the concentration of pollutants in the exhaust gas, so that the capacity of the system must be designed higher than with a continuous supply of hazardous waste. In the second process, the filled containers, which must also be incinerated due to their contamination with the special waste they contain, are pre-shredded in a shredder. In a drum sieve, the metal scrap and other solids are separated from the special waste, which is usually in the form of a pasty or pasty slurry, before both fractions are then continuously fed to the incinerator. However, such a method requires devices for feeding the thick matter as well as for feeding the solids into the incinerator.

When special waste and containers are burned together, one mostly falls into small pieces or granular ones Form present burning from rusty fused sheet metal or iron parts, which should be fed to a new combustion due to its residual calorific value and to reduce the amount of combustion residues.

US Pat. No. 3,559,823 discloses a method and a device with the features of the preamble of claims 1 and 8, respectively. The delivery piston is rigidly connected there to the rod of a double-acting hydraulic cylinder.

From US Pat. No. 4,096,797 it is known for a sludge press to close the discharge end of a press drum cooperating with a piston by means of a knife-like slide valve during the return stroke of the piston.

Furthermore, it is known from CH-A-513 378 for a loading device of a waste incineration plant to provide a trough connected to the combustion chamber, the furnace-side end of which has a feed opening provided on its periphery with a cutting edge and in which a push-in slide is arranged displaceably is provided on the furnace side with a cutting edge which interacts with the cutting edge arranged on the circumference of the feed opening.

Proceeding from this, the object of the invention is to develop a method and a device of the type mentioned at the outset which enable substantially continuous conveyance of pre-comminuted metal scrap or similar solid materials containing solid matter.

This object is achieved according to the invention by a method in which the thick matter containing the pre-comminuted metal scrap is pressed into a feed cylinder by a plunger-like feed piston from a feed container which is tightly underneath the bottom of the feed piston and which is limited on the inlet side during each feed stroke and thereby sealed over a feed cylinder a container-side inlet opening of the feed cylinder from the feed container into the feed cylinder projecting parts of the shot are sheared off by the feed piston entering the feed cylinder with its front end, the feed force of the feed piston being increased when a predetermined pressure in a medium driving the feed piston is exceeded. The invention is based on the idea of conveying the thick matter containing the pre-shredded container scrap with a piston pump, since piston pumps have proven to be excellent in conveying thick matter with different liquid contents, and in the course of the conveyance only crushing the container scrap that is in the uncrushed form would hinder funding. The increase in the feed force and thus the shear force permits the shearing off of larger or thicker solids which protrude from the feed cylinder into the feed container.

If solid bodies which are stuck between the delivery piston and the inlet opening cannot be sheared off, a further advantageous embodiment of the invention provides that the delivery piston is retracted when a predetermined pressure in the pressure oil circuit is exceeded and then pushed forward again. Due to the suction effect when the delivery piston is pulled back, the piston path is blocked by blocking solids, so that they are completely in the delivery line or in the feed container during the subsequent pressure stroke of the delivery piston or penetrate the inlet opening of the delivery cylinder with a smaller shear cross section. If this measure does not immediately shear off the solids, this process can be repeated automatically several times before the pump is stopped.

A preferred embodiment of the invention provides that the protruding parts between at least one edge at least partially surrounding the inlet opening of the feed cylinder and at least one at the inlet of the feed piston are sheared off in the feed cylinder at a short distance past the edge and arranged at the front end of the feed piston. Such a procedure makes it possible to shred only the solids which are located partly in the feed container and partly in the feed cylinder when the feed piston enters the feed cylinder. This significantly reduces the amount of energy required for shredding.

According to an advantageous embodiment of the invention, the translational movement of the feed piston is superimposed on its feed movement by a rotary movement about the feed piston axis in order to improve the cutting action between the stationary edge and the cutting edge at the front end of the feed piston. The rotary movement of the delivery piston can, for example, take place hydraulically via a rotary piston of a drive cylinder.

Another advantageous embodiment of the invention provides that a return of the thick matter in the feed cylinder is prevented during a suction stroke of the feed piston by closing a slide arranged in the feed cylinder, which is opened synchronously with the movement of the feed piston whenever the feed piston is fully retracted , and is closed when the delivery piston is fully extended.

With regard to the device, the object underlying the invention is achieved in that the delivery piston is designed as a plunger cylinder, and that the plunger cylinder is hydraulically displaceable relative to a piston of a stationary piston rod engaging in the plunger cylinder, with a delivery side between the piston during a pressure stroke and pressure chamber arranged in the plunger cylinder can be acted upon with pressure oil together with a pressure chamber arranged on the rod side between the piston and the plunger cylinder, and if a predetermined pressure in the pressure spaces is exceeded while closing a connection between the pressure spaces, the rod-side pressure space can be switched without pressure. If, in such an arrangement, the pressure chamber on the delivery side has a cross-section twice as large as the pressure chamber on the rod side, with a constant drive power of a drive pump acting on the plunger cylinder with pressure oil, the feed force and thus the shear force at the front end of the delivery piston can be doubled by halving the feed speed.

According to a preferred embodiment of the invention, the cutting means are formed by at least one edge that at least partially surrounds the inlet opening of the feed cylinder and at least one cutting edge that is guided past the edge at a small distance when the feed piston enters the feed cylinder and is arranged at the front end of the feed piston, the edge and the cutting edge preferably consist of hard metal or hardened steel. While the edge is expediently formed on a cutting ring made of hardened steel or hard metal on the container-side end of the feed cylinder, the cutting edge is preferably arranged on a cutting crown which can be detachably attached to the front end of the feed piston between an end face facing the feed cylinder and a peripheral surface of the feed piston. The circumferential cutting edge can be zigzag or wave-shaped in the conveying direction and / or in the radial direction, so that the solid protruding from the feed container into the conveying cylinder is not blunt-cutting but sheared, which enables the solids to be broken up more easily. As an alternative to this or in addition, the edge of the inlet opening can also be zigzag or wavy.

The zigzag design of the cutting edge is thereby according to a further advantageous embodiment of the invention achieved that it is formed by a ring-shaped arranged next to each other, protruding forward over the cutting crown, which are expediently formed in one piece with the cutting crown.

In order to facilitate the introduction of the delivery piston, which is not guided in the area of the feed container, into the inlet opening of the delivery cylinder, the cutting crown arranged at the front end of the delivery piston, the outside diameter of which corresponds to the outside diameter of the delivery piston, expediently has a conical chamfer in the area of the cutting edge.

According to a further advantageous embodiment of the invention, the delivery plunger has at least one annular groove in the area of its front end face on its circumferential surface, by means of which the sealing of the annular gap measuring several tenths of a millimeter between the delivery plunger and the delivery cylinder is improved. The annular groove usually replaces elastic seals arranged at this point, which would be easily damaged by the metal parts being conveyed and would therefore be unusable.

However, since the annular groove or the annular grooves during the pressure stroke cannot prevent the entry of smaller metal parts into the annular gap between the delivery piston and delivery cylinder, an inner wall surface of a section of the delivery cylinder adjoining the feed container and an outer circumferential surface opposite the inner wall surface when the delivery piston is extended are expedient Delivery piston hardened. A hardening distortion occurring during the hardening of the feed cylinder section and the feed piston can be compensated for by the part of the feed cylinder and the feed piston being turned so convexly during manufacture that the warping leads to an incidence on exact cylinder surfaces.

In contrast to known piston pumps, in which the feed container In its lower part, it was always deeper and wider than the cross-section of the delivery piston in order to prevent wear of elastic seals arranged at the front end of the delivery piston, the lower part of the feed container according to a further preferred embodiment of the invention has an essentially the cross-section of a preferably semi-circular delivery piston segment corresponding cross section. This measure makes it possible to prevent metal parts in the lower half of the delivery piston cross-section from protruding from the delivery line into the feed container, so that cutting means could be dispensed with in the area of the lower half of the delivery piston and the lower half of the inlet opening. As an alternative to this, symmetrically designed cutting means can also be reinstalled rotated by 180 degrees after one-sided wear. In order to prevent rubbing of the peripheral surface of the feed piston in the lower part of the feed container despite a slight deflection of the feed piston which is not guided in the area of the feed container and a rougher surface of the bottom of the feed container compared to the surface of the hydraulic cylinder, the cross section of the lower part of the feed container is preferably around a few tenths of a millimeter larger than the delivery piston diameter. The bottom of the feed container can be designed as a releasably attachable lining made of wear plate.

According to a further advantageous embodiment of the invention, a so-called bridge breaker is in the area of the feed container arranged, which presses the thick materials into the feed container, thus ensuring that material bridges in the feed container are destroyed and that the thick materials cannot escape upwards through a feed hopper of the feed container during the feed of the feed piston, but rather are pressed through the inlet opening into the feed cylinder.

In order to prevent that the thick materials pressed into the feed cylinder during the pressure stroke of the feed piston are conveyed back into the feed container during the suction stroke of the feed piston, a feed cylinder is arranged in the feed cylinder that releases the feed cylinder before a pressure stroke of the feed piston and closes the feed cylinder before a feed stroke of the feed piston Slider provided, which is synchronized with the delivery piston and is arranged directly behind the point at which the front end of the delivery piston is located when the delivery piston is fully extended.

In order to ensure that the solid bodies conveyed together with the thick matter cannot lead to a jamming of the slide, the slide according to the invention has a slide blade which can be displaced in a guide and engages in the feed cylinder and in which at least the edge opposite the guide has a wedge-shaped in the feed direction Has cross section. The wedge shape of the edge ensures that material that penetrates into the guide when the slide is withdrawn from the feed cylinder is easily pushed out again and does not get stuck in the narrow gap between the guide and the slide blade and thus leads to jamming of the slide blade .

The edge of the slide blade opposite the guide is expediently adapted in its contour to the inner cross section of the feed cylinder and, when the slide is closed, lies against a stop with a semicircular fit, the inner cross section of the feeder, which fits into the feed cylinder opposite the guide Delivery cylinder corresponding stop surface.

When the slide is closed, any solid bodies in the slide path are pressed by the slide blade against the stop surface of the stop. The slide can then not be closed completely, but the clamped solid bodies also prevent the thick materials from flowing back from the feed cylinder into the feed container.

In order to improve the filling level in the feed container, it is proposed according to a preferred embodiment of the invention that a feed chute opening into the feed container and a preferably hydraulically actuable stop member which can be inserted into the feed container in the direction of the feed container are provided. The stop element is expediently slidable into the feed shaft, preferably into the feed container. In order to avoid bridging in the feed shaft, a preferably hydraulically operable bridge breaking member, which can be inserted essentially transversely to the displacement path of the stop member into the feed shaft, is advantageously provided, which can be expediently inserted into the feed shaft transversely or obliquely in the direction of the feed container above the stop member. To make assembly easier, the feed shaft has two flanges, which are arranged at an angle on the shaft casing, for fastening a tamping cylinder and a bridge breaker cylinder. When operating the conveyor device, care must be taken that the delivery piston, which is preferably in the form of a plunger cylinder, the stop member, the bridge-breaking member and the slide are appropriately controlled cyclically by a central control.

Fig. 1

eine Seitenansicht einer Vorrichtung gemäß der Erfindung;

Fig. 2

eine Draufsicht auf die Vorrichtung nach Fig. 1;

Fig. 3

einen Längsschnitt durch die Vorrichtung entlang der Linie A - A der Fig. 1;

Fig. 4

eine vergrößerte Darstellung des Ausschnitts X aus Fig. 3;

Fig. 5

eine Vorderansicht des vorderen Stirnendes des Förderkolbens;

Fig. 6

eine vergrößerte Darstellung des Ausschnitts Y aus Fig. 3 beim Eintritt des Förderkolbens in den Förderzylinder;

Fig. 7

eine vereinfachte schematische Darstelllung des hydraulischen Antriebs der Kolbenpumpe;

Fig. 8

eine Vorderseitenansicht des in den Fig. 1 und 2 in eingebautem Zustand dargestellten Schiebers;

Fig. 9

einen Querschnitt durch den Schieber entlang der Linie C-C der Figur 8;

Fig. 10

die Fördervorrichtung in einer Darstellung entsprechend Fig. 1 mit Zuführschacht, Stopfzylinder und Brückenbrecher;

Fig. 11

eine Stirnseitenansicht der Vorrichtung nach Fig. 10;

Fig. 12

eine Draufsicht auf den Zuführschacht nach Fig. 10 und 11.

The invention is explained in more detail below with reference to an exemplary embodiment shown schematically in the drawing. Show it

Fig. 1

a side view of a device according to the invention;

Fig. 2

a plan view of the device of FIG. 1;

Fig. 3

a longitudinal section through the device along the line A - A of Fig. 1;

Fig. 4

an enlarged view of section X of Fig. 3;

Fig. 5

a front view of the front end of the delivery piston;

Fig. 6

an enlarged view of section Y of Figure 3 when the feed piston enters the feed cylinder;

Fig. 7

a simplified schematic representation of the hydraulic drive of the piston pump;

Fig. 8

a front view of the slide shown in Figures 1 and 2 in the installed state.

Fig. 9

a cross section through the slide along the line CC of Figure 8;

Fig. 10

the conveyor in a representation corresponding to Figure 1 with feed shaft, stuffing cylinder and bridge breaker.

Fig. 11

an end view of the device of FIG. 10;

Fig. 12

a plan view of the feed shaft of FIGS. 10 and 11th

The device shown in the drawing is to be used in order to supply liquid, pulp-like and pasty special waste delivered in drums to a rotary kiln for incineration essentially continuously. In addition, with this device, the part of the burnout consisting of rusty, fused sheet metal parts or other unburned iron scrap from the rotary kiln is to be fed to it again in order to reduce the residual waste amount after the combustion and to utilize the remaining calorific value of this part of the burnup. While the barrels with the special waste are pre-shredded in a shredder (not shown), the fused sheet metal parts separated from the erosion by magnetic separation are mixed with a liquid or pasty carrier material, preferably also liquid or pasty special waste, before the resulting solid / thick mixture with device according to the invention is fed into the rotary kiln.

The device shown essentially consists of a hydraulically driven single-piston pump 2, from the delivery piston 4 of which the solid / thick mixture is pressed from a feed container 6 via a delivery cylinder 8 into a delivery line leading to the rotary kiln (not shown). A arranged behind the feed cylinder 8, clocked in accordance with the movement of the feed plunger 10 closes the feed line before pulling back the feed piston 4 and thus prevents the mixture from being fed back into the feed container 6 when the feed piston 4 is pulled back.

In order to prevent sheet metal parts or other metallic solid bodies protruding from the feed cylinder 8 into the feed container 6 from jamming of the feed piston 4 in the feed cylinder 8, the feed piston 4 has a cutting crown 14 made of hardened steel at the front end 12 which, when entering the Delivery cylinder 8 for shearing off the protruding sheet metal parts or other solid body cooperates with a cutting ring 18 also made of hardened steel. The cutting ring delimits an inlet opening 16 through which the solid / thick mixture is pressed out of the feed container 6 into the feed cylinder 8.

The cutting ring 18 has a plurality of lubrication bores 172 which are arranged distributed over the circumference and open into a radially inwardly open annular groove 170. The lubrication holes are loaded with lubricating oil via a central lubrication system in the pump cycle at the moment the delivery piston 4 is immersed in the cutting ring 18. With these precautions, there is a considerable reduction in wear for the delivery cylinder 8 and the downstream delivery line (FIG. 6).

As can be seen from FIG. 3, the conveying cylinder 8 has an annular channel 178 which can be acted upon by cooling water via the connections 180 in the direction of the arrows 182. Water cooling becomes necessary when the medium to be pumped is permeated with steam.

To shear off the sheet metal parts, the cutting ring 18 has, on its end face 20 facing the feed container 6, an edge 22 surrounding the inlet opening 16, on which a cutting edge 24 of the cutting crown 14 is passed at a small distance when the feed piston 4 enters the feed cylinder 8. While the edge 22 of the cutting ring 18 is circular, the cutting edge 24 runs in a zigzag shape on a conical chamfer surface 28 which limits a cylindrical circumferential surface 26 of the cutting crown 14 to the front, the chamfer surface 28 introducing the delivery piston 4 not guided in the area of the feed container 6 into the Entry opening 16 should facilitate. The zigzag-shaped cutting edge 24 delimits the end face via a central circular end face 30 of the cutting crown 14, which protrudes forwardly and is made in one piece with the cutting crown 14 30 surrounded by a ring. The cutting bodies 32 have a triangular cross section in the tangential direction and are delimited to the front by roof surfaces 36, 38, 40 inclined toward one another and towards the piston axis 34, which cause the delivery piston 4 to enter the inlet opening 16 from the delivery cylinder 8 when the delivery piston 4 enters sheet metal parts protruding into the feed container 6 are displaced in the tangential and radial directions relative to the guide surfaces 36, 38, 40, thereby making their shearing easier.

The cutting crown 14 is detachably fastened with axial fastening screws 59 on a front end 41 of the delivery piston 4 facing the delivery cylinder 8. The threaded bores for the fastening screws 59 are arranged at regular angular intervals, so that the cutting crown 14 can be removed if the cutting edge 24 wears on one side and can be fastened again after rotation by a corresponding angle about the piston axis 34.

At a short distance behind the cutting crown 14, the delivery piston 4 has two or more annular grooves 39 arranged one behind the other on its peripheral surface 37. The annular grooves 39 have a rectangular cross section, the ratio between their depth and their width being approximately 1: 2. The distance between the two ring grooves 39 corresponds essentially to their width. The annular grooves 39 act as relief grooves and have the effect that the pressure drop in the gap 41 between the peripheral surface 37 of the delivery piston 4 and the inner surface of the delivery cylinder 8 increases compared to a delivery piston without annular grooves and thus the backflow of thick matter through the gap 41 during the feed movement of the delivery piston 4 is difficult. The annular grooves 39 replace the elastic seals usually arranged at this point in piston pumps, which are not used in the piston pump according to the invention, since they would be quickly damaged or destroyed by the sharp sheet metal parts.

The peripheral surface 37 of the delivery piston 4 is hardened to prevent small metal particles entering the gap 41 from causing damage to the peripheral surface 37.

The feed container 6 has two mutually opposite parallel walls 40, 42 in the conveying direction of the conveying piston 4, each of which is provided with a circular passage opening 44, 46 for the conveying piston 4. In the passage opening 44 in the wall 40 delimiting the feed container 6 to the feed cylinder 8, the annular cutting ring 18 is inserted against an annular flange 48 at the container-side end of a first section 50 of the feed cylinder 8 such that it is rotated by a corresponding amount in the event of one-sided wear can. A guide cylinder 52 of the single-piston pump 2 is connected to the passage opening 46 in the opposite wall 42 of the feed container 6, in which the delivery piston 4 is guided. To the sides and downwards, the feed container 6 is delimited by a trough 56 lined with wear plates 54, the lower part of which has a semicircular cross section. The diameter of the semicircular part of the tub cross section is only a few tenths of a mm larger than the diameter of the delivery piston 4, so that it is ensured that on the one hand the delivery piston 4 does not rub against the tub 56, but on the other hand no sheet metal parts during the advance of the delivery piston 4 or other solids get into the gap between delivery piston 4 and tray 56. As a result of this measure, when the cutting crown 14 enters the delivery line 8, sheet metal parts protrude from the feed container 6 into the delivery line 8 only in the upper part of the tub 56, so that on the one hand the feed force of the delivery piston 4 required for shearing off the sheet parts is reduced, and on the other hand in the lower half of the cutting ring 18 and the cutting crown 14 there is no wear of the edge 22 or the cutting edge 24. After wear of the edge 22 or the cutting edge 24 in the upper part of the cutting ring 18 or the cutting crown 14 can thus be rotated 180 degrees about the piston axis 34 and thus their service life can be doubled.

At its upper edge 58, the feed container 6 is provided with a horizontal screw flange 60, on which a hopper or feed shaft 200 can be placed. The feed shaft is provided with two obliquely aligned jacket flanges 202, 204 which are equipped with a hydraulic stuffer cylinder 206 and a hydraulic bridge breaker cylinder 208. The tamping cylinder 206 has a piston rod 210 designed as a stopping device, which can be displaced obliquely in the direction of the feed container 6 into the feed shaft 200. The bridge breaker cylinder 208 has a piston rod 212 which is displaceable transversely to the direction of displacement of the stop element 210 and is designed as a bridge breaker and which passes through the feed shaft 200 transversely when shifted. At its upper end, the feed shaft 200 is provided with a horizontal screw flange 214, to which a feed channel (not shown) can be flanged. As long as the delivery piston 4, which is designed as a plunger cylinder, is displaced into its rear end position, the solid / thick material mixture can reach the feed container 6 via the feed shaft 200. As soon as the delivery piston 4 is displaced in the conveying direction, the stop member 210 is also displaced in the direction of the feed container 6, taking the mixture in front of it, so that compression and thus a good degree of filling result. As soon as the delivery piston 4 dips into the delivery cylinder 8, the stop member 210 is moved back into its end position so that new material can be conveyed from above. When the delivery piston 4 is then pushed back again, releasing the material opening in the feed container, the bridge breaker 212 is actuated in order to sever material bridges which may occur in the feed shaft 200. The delivery piston 4, the slide 10, the stuffing cylinder 206 and the bridge breaker cylinder 208 are controlled via a central control according to a defined cycle (Figs. 10 to 12).

The first section 50 of the feed cylinder 8, which adjoins the feed container 6 and extends to the slide 10, has a cylindrical tube wall 43 made of hardened steel in order to prevent damage to the inner wall surface by metal particles penetrating into the gap 41 between it and the feed piston 4 prevent. A hardening distortion occurring during hardening of the cylindrical tube wall 43 can be compensated for in that the tube wall 43 is convexly pre-turned before hardening, so that the hardening distortion leads to the formation of an exactly cylindrical inner wall surface.

The guide cylinder 52 adjoining the wall 42 of the feed container has on its inner circumferential surface 49 in the area of the passage opening in the wall 42 a wiper 51 and immediately behind the wiper 51 a plurality of sealing rings 53 and guide belts 55 arranged one behind the other in the conveying direction. While the wiper 51 and the sealing rings 53 prevent the entry of thick materials between the delivery piston 4 and the guide cylinder 52, the guide belts 55 serve to guide the delivery piston 4 in the guide cylinder 52. The gap between the guide cylinder 52 and the delivery piston 4 is via the lubrication holes 174 in the direction of arrows 176 through a central lubrication system with lubricating oil.

The delivery piston 4, as shown in simplified form in FIG. 7, is designed as a plunger cylinder 57, which is displaceable relative to a piston 58 of a piston rod 60 arranged stationary in the guide cylinder 52. The piston rod 61 has two pressure oil channels 66, 68, each of which can alternatively be connected to a pressure oil supply line 62, 64 leading to a drive pump 80 or to a return flow line 78, 79 leading to a return flow tank 76 ', and one of which flows into a delivery side the piston 59 and the plunger cylinder 57 arranged pressure chamber 70 and the other opens into a pressure chamber 72 arranged on the rod side between the piston 59 and the plunger cylinder 57. The effective piston area in the pressure chamber 70 on the delivery side is twice as large as the effective piston area in the pressure chamber 72 on the rod side, since the cross section of the piston rod 61 is half the size of the cross section of the pressure chamber 70 on the delivery side. The two pressure chambers 70, 72 are connected by a closable connecting line (not shown) connected to each other, which is opened when the two pressure chambers 70, 72 are pressurized with pressure oil (differential control), so that pressure equalization is established and pressure oil can be conveyed from the rod-side pressure chamber 72 to the delivery-side pressure chamber 70.

The pressure in the pressure oil channel 68 is monitored by two pressure transducers 76, 77, which act upon a control unit 82 with a control signal each time a predetermined pressure is exceeded during the advancing movement of the plunger cylinder 57.

In normal operation of the device, both pressure chambers 70, 72 are actuated with differential control open in the compensation line and pressurized via the pressure oil supply lines 62, 64 and the pressure oil channels 66, 68 connected to them. Since only the rod surface is available as the active surface, the plunger cylinder 57 is advanced with a relatively low feed force, but with a relatively high feed speed. If, however, a sheet metal strip with a greater thickness of material protrudes from the delivery line 8 into the feed line 6 when the delivery piston 4 enters the delivery line 6 and cannot easily be sheared off between the edge 22 and the cutting edge 24, the pressure spaces 70, 72 and in the pressure oil channels 66, 68 a pressure which, when the predetermined value at the first pressure sensor 76 is exceeded, leads to the control unit 82 closing the connection of the pressure oil channel 66 to the pressure oil supply line 62 and the pressure chamber 72 with the Return flow line 78 connects, so that only the delivery-side pressure chamber 70 is pressurized with pressure oil, while the rod-side pressure chamber 72 is depressurized. As a result, the feed force and thus the shear force between the cutting edge 24 and the peripheral edge 22 are doubled, while the feed speed is halved, with the same delivery capacity of the drive pump 80.

If the doubling of the feed force does not lead to a shearing off of the sheet metal strip clamped between the cutting edge 24 and the edge 22, the pressure in the pressure oil circuit continues to increase until it exceeds the predetermined value at the second pressure sensor 77 and a signal is sent to the control unit 82 by the latter becomes. The control unit 82 then connects the pressure oil channel 68 to the return flow line 79 and the pressure oil channel 66 to the pressure oil supply line 62, so that now only the rod-side pressure chamber 72 is pressurized and the plunger cylinder 57 is withdrawn. When the feed plunger 4 is pulled back, the suction in the feed container 6 causes the thick matter to collapse, the metal strip blocking the feed movement of the feed plunger 4 also mostly being displaced. After reaching its end position, the plunger cylinder 57 is pushed again, the pulling back and the pushing forward being able to be repeated several times before the piston pump is stopped for manual removal of the sheet metal strip.

The slide 10 arranged in the delivery line 8 essentially consists of a slide blade 94, which is guided in a slide flange 92 so as to be vertically displaceable, which completely releases the delivery line 8 when the slide 10 is open and closes it completely when the slide 10 is closed. The spade-shaped slide blade 94 is displaceable by means of two hydraulic cylinders 96, 98, each with its piston rod 100 on the slide blade 94 and with its cylinder 102 on the slide flange 92 built into the delivery line 8 attack.

The part of the slide blade 94 which engages in the delivery line 8 is delimited at the bottom by a semicircular edge 104 which is adapted to the inner cross section of the delivery line 8 and which, when the slide 10 is closed, has a semi-cylindrical stop surface 106 on a likewise semi-cylindrical stop surface 108 of a between two parallel flange plates 110, 112 of the slide flange 92 inserted stop plate 114 abuts. Above the conveying line 8, the slide blade 94 is guided in a guide shaft 116 arranged between the flange plates 110, 112 with a guide slot 118 which is rectangular in cross section, the opposite broad side surfaces 122 of which lie opposite the wide side surfaces 124 of the slide blade 94, each leaving a narrow gap 120.

In the conveying direction, the edge 104 of the slide blade 94 has a cross section which tapers in a wedge shape towards the stop surface 106, which ensures that metal particles which get into the narrow gap 120 between the slide blade 94 and the guide shaft 116 when the slide blade 94 is pulled out of the delivery line 8, when the slide blade 94 is subsequently pushed into the delivery line 8, it is pushed back out of the gap 120 toward the delivery line 8 and does not get stuck between the slide blade 94 and the guide shaft 116.

The guide shaft 116 is formed in two parts, the lower part 126 being supported against a ring 128 delimiting the flange plates 110, 112 towards the inside of the conveying line 8, and the upper part 130 being supported by adjusting screws 132 engaging in threaded holes in the flange plates 110, 112 the top of the lower part 126 resting seal set 134 is pulled. The sealing set 134 is made of elastic seals 136, 138 which run around the slide blade 94 thereby pressed together, the seals 136, 138 bearing against the slide blade 94.

The two sections of the delivery line 8 in front of and behind the slide 10 are each held by fastening screws 140 which engage in threaded holes in the flange plates 110, 112 on the flange plates 110, 112 and are themselves connected to one another by connecting screws 142.

The slide blade 94 is also formed in two parts, the lower part, which engages in the guide slot 118 of the guide shaft 116, being connected by retaining screws 144 to the upper part, which projects beyond the flange plates 110, 112 transversely to the conveying direction and has cylindrical receptacles 146 pointing downward , in which cylindrical pins 148, each protruding on the end face via the piston rods 100 of the hydraulic cylinders 96, 98, are fastened with retaining bolts 150.

On the cylinder side, the hydraulic cylinders 96, 98 are pivotably mounted on pivot bolts 152, which are inserted in brackets 154 which project laterally beyond the flange plates 110, 112.

A closed sheet metal housing 156 is placed on the flange plates 110, 112, in which the slide blade 94 moves upwards, protected against external influences, when it is pulled out. In the wall 158 of the sheet metal housing 156, two proximity switches 160, 162 are inserted, each of which responds in the upper and lower end positions of the slide blade 94 when a flange 164 projecting over the slide blade 94 in the conveying direction approaches.

The signal supplied by the limit switches of the control unit 82 serves to supply the pressure oil to the hydraulic cylinders each time the upper or lower end position of the slide blade 94 is reached 96, 98 to close and then initiate the feed movement or the retraction of the delivery piston 4, which is synchronized with the slide 10.

The slide 10 is arranged in the conveying direction immediately behind the point in the delivery line 8 at which the front end 12 of the delivery piston 4 is located when the delivery piston 4 is fully extended. It is thereby achieved that when the delivery piston 4 is pulled back on the container side of the slide 10 there is no longer any thick material in the delivery cylinder 8 which is sucked back to the feed container 6.

Claims (40)

1. A method for conveying thick matter containing shredded scrap metal or similar solids, in which the thick matter is pressed by a plunger-like conveyor piston (4) from a feed container (6) into a conveyor cylinder (8), wherein the bottom of the feed container closely fits under the conveyor piston (4) and is limited or closed on its inlet side during each conveying stroke, and wherein solids projecting over the inlet opening (16) of the conveyor cylinder (8) on the side of the container are sheared off by the conveyor piston (4) entering with at least its forward end into the conveyor cylinder (8), characterized in that the feeding force of the conveyor piston (4) is increased upon exceeding a specified pressure in a medium which drives the conveyor piston (4).
2. The method of claim 1, characterized in that the solids are mixed with a thick matter or a liquid medium in a first step of the method.
3. The method of claim 1 or 2, characterized in that the conveyor piston (4) is retracted upon exceeding a specified pressure in a medium driving the conveyor piston (4) and is subsequently moved forward again.
4. The method of one of claims 1 to 3, characterized in that the solids are sheared off by at least one rim edge surrounding the inlet opening (16) and at least one cutting edge (24) which is positioned on the forward end of the conveyor piston (4) and which is moved at a small distance past the rim edge during the entry of the conveyor piston (4) into the conveyor cylinder (8).
5. The method of one of claims 1 to 4, characterized in that a rotary movement is superposed over the translational movement of the conveyor piston (4).
6. The method of one of claims 1 to 5, characterized in that a slide member (10) positioned in the conveyor cylinder (8) is closed prior to a suction stroke of the conveyor piston (4).
7. The method of claim 6, characterized in that during the closing of the slide member (10) solids located in the path of movement of a slide plate (94) engaging into the conveyor cylinder (8) are jammed between the slide plate and a wall of the conveyor cylinder.
8. A device for conveying thick matter, in particular for conveying thick matter containing shredded scap metal or similar solids, comprising a piston pump (2) which has a plunger-like conveyor piston (4), with which the thick matter is pressed from a feed container (6) into a conveyor cylinder (8), wherein the conveyor piston (4) has cutting means (14, 24) at its forward end (12) which enters the conveyor cylinder (8), which cutting means (14, 24) act together with cutting means (18, 22) in the region of an inlet opening (16) of the conveyor cylinder (8) at the container side, and wherein a lower part of the feed container (6) has a cross section corresponding essentially to the cross section of one conveyor piston segment, characterized in that the conveyor piston (4) is desigend to be a plunger cylinder (57), and that the plunger cylinder (57) is hydraulically movable relative to a piston (58) of a stationary piston rod (60) which engages into the plunger cylinder (57), wherein during a pressure stroke a pressure chamber (70) positioned on the conveying side between the piston (58) and the plunger cylinder (57) can be loaded with pressure oil together with a pressure chamber (72) positioned on the rod side between the piston (58) and the plunger cylinder (57), and upon exceeding a specified pressure in the pressure chambers (70, 72) the pressure chamber (70) on the rod side can be switched without pressure by closing a connection between the pressure chambers (70, 72).
9. The device of claim 8, characterized in that the cutting means (18, 22) are formed by at least one rim edge (22) which at least partially surrounds the inlet opening (16) of the conveyor cylinder (8) and by at least one cutting edge (24) which is positioned at the forward end (12) of the conveyor piston (4) and which is moved at a small distance past the rim edge (22) during the entry of the conveyor piston (4) into the conveyor cylinder (8).
10. The device of claim 9, characterized in that the rim edge (22) and the cutting edge (24) are made of hard metal or of hardened steel.
11. The device of claim 9 or 10, characterized in that the rim edge (22) is formed on a cutting ring (18) which is made of a hardened steel or of a hard metal and which is positioned at the container side of the conveyor cylinder (8).
12. The device of one of claims 9 to 11, characterized in that the cutting edge (24) is positioned on a cutting crown (14) which is removably connectable to the front forward end (12) of the conveyor piston (4).
13. The device of one of claims 9 to 12, characterized in that the cutting edge (24) is positioned between at least one front face (30) which faces the conveyor cylinder (8) and at least one peripheral surface (26) of the conveyor piston (4).
14. The device of one of claims 9 to 13, characterized in that the cutting edge (24) is formed to have a zigzag or wave shape.
15. The device of one of claims 9 to 14, characterized in that the cutting edge (24) forwardly delimits a conical bevel (28) at the front end of the cutting crown (14).
16. The device of claim 15, characterized in that the cutting edge (24) is formed by cutting members (32) which project forwardly over a cutting crown body (15).
17. The device of claim 16, characterized in that the cutting members (32) are formed to be one piece with the cutting crown body (15).
18. The device of claim 16 or 17, characterized in that the cutting members (32) are positioned in a ring-like fashion next to one another and that they have a triangular cross section in a tangential direction.
19. The device of one of claims 16 to 18, characterized in that the cutting members (32) are delimited by guide surfaces which are inclined toward one another.
20. The device of one of claims 15 to 19, characterized in that the outer diameter of the cutting crown (14) corresponds to the outer diameter of the conveyor piston (4)
21. The device of one of claims 8 to 20, characterized in that a section (50) of the conveyor cylinder (8) is made of a hardened steel, said section following the feed container (6).
22. The device of claim 22, characterized in that the section (50) extends at least to the point at which the forward end (12) of the conveyor piston (4) is located when the conveyor piston (4) is fully displaced.
23. The device of one of claims 10 to 22, characterized in that the conveyor piston (4) has a hardened peripheral surface (37).
24. The device of one of claims 10 to 23, characterized in that the lower part of the feed container (6) has a semicircular cross section having a diameter which is slightly larger than the diameter of the conveyor piston.
25. The device of one of claims 10 to 24, characterized in that the feed container (6) has at least in its lower part a removably fastened lining (54).
26. The device of one of claims 10 to 25, characterized in that the conveyor piston (4) has at least one annular relief groove in its peripheral surface in the region of its forward end (12).
27. The device of one of claims 10 to 26, characterized in that the conveyor piston (4) can be rotated about its piston axis (34) during a forward movement.
28. The device of one of claims 8 to 27, characterized by a device positioned in the region of the feed container (6) for pressing the thick matter into the feed container (6) and/or for holding the thick matter in the feed container (6) during a pressure stroke of the conveyor piston (4).
29. The device of one of claims 8 to 28, characterized by a slide member (10) which is positioned in the conveyor cylinder (8), which exposes the conveyor cylinder (8) prior to a pressure stroke of the conveyor piston (4), and which closes off the conveyor cylinder (8) prior to a suction stroke of the conveyor piston (4)
30. The device of claim 29, characterized in that the slide member (10) has a slide plate (94) which is movable in a guideway (116, 118) and which engages in the conveyor cylinder (8), wherein at least the edge (104) of the slide member opposing the guideway (116, 118) in the direction of conveying has a wedge-shaped cross section.
31. The device of claim 30, characterized in that the shape of the edge (104) opposing the guideway (116, 118) is matched to the inside cross section of the conveyor cylinder (8).
32. The device of claim 30 or 31, characterized in that the guideway (116, 118) has at least one seal (136, 138) resting against the slide plate (94).
33. The device of one of claims 29 to 32, characterized in that the slide member (10) is positioned at a small distance behind the point at which the forward end (12) of the conveyor piston (4) is located when the conveyor piston (4) is fully extended.
34. The device of one of claims 8 to 33, characterized in that the conveyor cylinder (8) has annular channel (178) which can be loaded with cooling water.
35. The device of one of claims 11 to 34, characterized in that the cutting ring (18) has lubricating bores (172) which are distributed about the circumference, which are open toward the inside, which preferably end in a radially inwardly open annular channel (170), and which can be loaded with lubricating oil by a central lubricating system in the cycle of pumping.
36. The device of one of claims 8 to 35, characterized by a feed chute (200) ending in the feed container (6) and a preferably hydraulically operable tamper member (210) which can be introduced into the feed chute (200) in the direction of the feed container (6).
37. The device of claim 6, characterized in that the tamper member (210) can be moved into the feed chute (200) at an angle, preferably up to the entry side of the feed container (6).
38. The device of claim 36 or 37, characterized by a preferably hydraulically operable bridge breaker member (212) which can be introduced into the feed chute (200) essentially transversely with respect to the path of movement of the tamper member (210).
39. The device of claim 39, characterized in that the bridge breaker member (212) can be introduced into the feed chute (200) above from the tamper member (210) transversely or inclined in the direction of the feed container (6).
40. The device of one of claims 36 to 39, characterized in that the conveyor piston (4), the tamper member (210), the bridge breaker member (212), and the slide member (10) can be controlled cyclically by means of a central control.

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