DE1942582A1 - Piston pump for liquid to solid substances, especially concrete - Google Patents

Description

Password: Combined pressure-travel reversal piston pump for liquid to solid materials, especially concrete The invention relates to a piston pump for liquid to solid substances, especially pulpy masses such as concrete, with double-acting hydraulic drives for pump pistons and material distributors.

The smooth operation of such pumps is primarily dependent of a proper functioning of the reversing of the drive piston for the Pump piston and the distributor of the conveyed material. The reversal must always be done first the distributor and only then can the pump drive be reversed, so that there is no return of the good in the infiltration funnel.

In order to use a hydraulic piston drive after completing a stroke Reversing the opposite stroke is usually a travel-dependent one Change of direction applied. In contrast, a pressure-dependent reversal has already been proposed as it is known on machine tools. With pressure-dependent reversal the pressure increase in the hydraulic circuit of the hydraulic drive when it occurs an increased variable resistance as a result of approaching an end stop as a control pulse exploited by actuating a pressure relief valve, the piston to the counter stroke is reversed. With this principle there is an accompanying phenomenon that is unwanted Work resistances before completion of the hub cause premature uncontrolling. It has been shown that in most cases the obstacle can be removed is not possible due to the early change of direction. Rather, it is reduced Movement of the pump plunger on an if-in-and-out. You can do the frequency Avoid such interruptions in operation by increasing the pressure value which is to be reversed. However, this brings the significant disadvantage with it that malfunctions may not be explained in time and as a result the pump parts are exposed to increased wear.

Finally, a particularly great disadvantage is that due to the high Reversing pressure in the drive cylinder for the pump piston, the high pressure medium heating that occurs, which reduce the viscosity and thus increase leakage losses as well leads to accelerated decomposition of the pressure medium.

The invention is now based on the object in the above to avoid the disadvantages described. To solve the problem, according to the basic idea the invention present @@@ gen, that by actuating a limit switch by the pump piston or its drive piston, the reversal of the pressure medium for the drive of the respective assigned distributor and by increasing the pressure in the hydraulic drive of the distributor, the corresponding reversal of the pressure medium is effected for the drive de3 respectively assigned pump piston.

The invention thus represents a combination of a path-dependent and a pressure-dependent one en reversal. It avoids with the comparatively large-volume drive cylinders for the pump piston a pressure medium heating, while this disadvantage in the the small-volume drive cylinder for the distributor slide barely matters, so that there the pressure-dependent reversal can be maintained without hesitation. This means that if there are any obstacles in the distributor slit gap - such as stones and the like. - A premature reversal of the slide and, as a result, a termination the same can be avoided.

It is recommended that the limit switch be actuated by an am Carry out the drive piston for the pump piston attached cable. This exists - in order to avoid tearing in the event of heavy use - appropriate to one Part made of an elastic material, preferably rubber, and the other part an almost inextensible material, preferably plastic with a steel core.

To prevent the pump piston from being extended - for example for cleaning, Repair or inspection purposes - to be made possible / in advantageous further training the invention fermer suggested that the stroke of the pump piston is designed to be adjustable. The adjustability of the pump piston stroke can be done in a simple manner Way can be achieved in that the cable is divided auseebilden and the adjacent ends of the cable parts by a releasable clamp coupling with each other are connected.

When the limit switch is actuated, the reversing of the Drives for both the pump piston and the distributor slide are electric Ways causes. In detail, the hydraulic drives are reversed according to a preferred embodiment of the invention by hydraulically operated control slide, which in turn each by an electromagnetically operated control slide are pilot operated.

The drives can be reversed one after the other to the effect that that first the reversal of the distributor drive and with a certain delay the reversal of the pump drive takes place. For the sake of simplicity however, it is preferred that by actuating the limit switch simultaneously and in the same way This causes the control slide for the pump piston and the distributor to switch will. A reliable follow-up dependency of the reversal can nevertheless be achieved in this way be that in the pressure line in front of the hydraulically operated control slide for the drive of the pump piston a - preferably controllable '- arranged switching valve is what the pressure line is at a certain pressure in the drive cylinder of the distributor releases.

In the event of operational malfunctions, which are usually caused by high pressures express in the lines and cylinders, it is necessary to have a short-circuit connection Provide pressure line-return line for the free flow of the pressure medium, in which connection a - preferably adjustable safety valve - is arranged is. But it is also advantageous if you have free circulation at any time - for example by operating a hand switch - can bring about. A form of guidance which enables this is characterized by a bypass line for the safety valve, in which an electromagnetically operated slide is arranged with a Position (II) for the free circulation of pressure medium and with a blocking position (I).

In the event of malfunctions caused by obstacles inside the pump cylinder it is ########## expedient to remove the obstacles, if the solenoid operated pilot valve and thus also the hydraulically actuated control spool can be switched in opposite directions, so that the pump cylinder in the opposite sense - that is, from the delivery line back into the pump hopper - conveys. In this regard, it is proposed in detail that that the reversal of the pump for delivery takes place in the opposite sense of IIand, so that an electrical switch can be operated and that when you release the Switch automatically reverses the pump to normal delivery mode he follows.

Furthermore, an embodiment is conceivable which is characterized by this is that the reversal of the pump for delivery in the opposite sense is automatic takes place, in dependence of a certain pressure in the Drive cylinder of the pump piston.

The above-described change in price for the pump and distributor drive each by an electromagnetically operated pilot servo slide and a hydraulically operated control slide can also be used except for single-cylinder pumps for pumps with two pump pistons each working in alternating rhythm and distributors and a corresponding number of drives are used for the same be, in such a way that each between a pair of drive cylinders a hydraulic There is a connection such that the piston executing a forward stroke located pressure medium is pressed into the other drive cylinder and the reverse stroke of the piston there causes.

Here, too, it is recommended for the reasons already mentioned above to make the stroke of the drive cylinder adjustable.

According to the invention, this is to be achieved by a manually switchable feed line are effected by valves, which with The pressure line is connected and into the cylinder space in front of the drive piston flows out.

A separate feed line is provided for each drive cylinder pair, in each of which a safety valve is arranged. ) The invention is now explained in more detail in the drawing and the following description using an exemplary embodiment FIG. 2 shows a hydraulic circuit diagram for the pump according to FIG. 1 and FIG. 3 shows the detail III in FIG. 2 in an enlarged, detailed representation.

According to the drawing are the drive pistons for the pump pistons.

10, 11 denoted by 12, 13. They can be moved in cylinders 14, 15 arranged. The drive cylinder is driven by a container 16 in a pressure line 17 by means of a hydraulic pump 18 pressure medium conveyed. On the way to the drive cylinders 12, 13 the pressure medium first passes through switchover valve 19, which is explained in more detail below, and then a hydraulic one actuated spool 20 with two positions I and II. When in ri-. 2 shown Position I of the control slide 20, the pressure medium passes into a line 21 which opens into the cylinder chamber 22 behind the drive piston 12 and this in the conveying direction (Arrow 23) moved.

Since: in the cylinder space 24 in front of the piston 12 pressure medium reaches the cylinder chamber 26 in front of the drive piston via a connecting line 25 13 and moves it back to its original position. That under the drive piston 13 located pressure medium flows via a line 27 over the control slide 20 ir a uit 28 designated return line and becomes a pressure medium container through this 29 supplied, which is connected to the container 16 in a manner not shown.

In position II of the control slide 20, the line 27 is connected to the Pressure line 17 and line 21 are connected to the return line 28. It can now the drive of the piston 13 and accordingly the return position of the piston 12 take place.

As can be seen in particular from Fig. 1, the drive takes place Pump piston 10, 11 in the direction of arrow 23 in each case the delivery stroke of the pump. Around a return of the from a Sinfülltrichter 30 in the respective delivery cylinder To prevent 31 or 32 reaching conveyed material 33 is during each conveying stroke to lock the respective connection hopper-delivery cylinder, whereas during of the suction stroke, the respective delivery cylinder must be blocked. To this end are two Distributor slide 34, 35 provided, each with a hydraulically driven Drive piston 36 and 37 are rigidly connected.

Of the. The drive pistons 36, 37 are driven in a similar manner wXe the above-described actuation of the drive pistons 12, 13 for the pump pistons 10, 11 and can be seen from FIG. It is again a pressure line 38 and a return line 39 is provided, which in the already mentioned lines 17 or 28 minutes. The pressure medium passes hydraulically from the pressure line 38 via a actuated control slide 40 (corresponding to the control slide 20) with two positions I and II in lines 41 and 42 and from there into the cylinders 43 and 44 of the drive piston 36 or 37. In the position I of the control slide shown in FIG. 2, the piston is 36 pressurized, while the anqere piston 37 - via a connecting line 45, which corresponds to the aforementioned connection line 25, of the pressurized on the other side - is at its rear dead center. In this position of the control slide 40, the line 42 is connected to the return line 39 connected. In position II of the control slide 40, the actuation takes place Drive piston 36, 37 in reverse, so that there is no further explanation seem necessary.

In order to optimize the efficiency of the pump with regard to its delivery and suction line, it is - as already indicated above - absolutely necessary, to precisely coordinate the cycles of the pump drive with those of the distributor drive, in such a way that the reversal of the distributor drive always varies in time The pump drive is reversed. According to that shown in FIG Embodiment this problem / manner described below is solved. Located a drive piston for a pump piston (in Fig. 2, for example, the drive piston 12) in its rear end position, which is a termination of the suction stroke of the associated Pump piston means that it is actuated by a cable 46 attached to it and 3 or 47 an electrical limit switch 48 or 49. According to FIG the limit switch 48 is actuated. A signal emanating from this reaches one with 50 designated switch cabinet and triggers the closure of a circuit there from, in which two electromagnets 51, 52 are arranged. The electromagnets 51, 52 serve for the simultaneous actuation of one servo control slide 53 and 54 respectively with two positions I and II. The servo control slide 53 or 54 is for actuation of the control slide 20 and 40 already described are provided. As from Fig. 2 can be seen, when the limit switch 48 is actuated, the servo control slide 53 54 pulled into position I. A servo line connected to the pressure line 38 55 then directs dos pressure medium into a cylinder 56 and causes a Compression spring 57 a displacement of the control slide 40 also in its position I. As already explained in more detail above, the drive piston 36 is thus pressurized. He is according to Pig. 2 already in its front end position, in which the associated distributor slide blocks the delivery cylinder. The one of the pump drive piston 10 assigned distributor drive piston 37 is, however, in its upper one End position at which the assigned distributor slide blocks the intake duct and releases the conveyor channel.

In the end position of the distributor drive piston 36, 37 thus has a view in the line 41 the full pressure of approx. 150 supplied by the hydraulic pump 18 atü built up via a secondary line 58 branching off from the pressure line 38 acts on the opening mechanism of the switching valve 19. This then gives clears the way for the pressure medium, which moves in the manner already described of the pump drive piston 12 in the conveying direction (arrow 25) and of the other pump drive piston 13 bev / trk in suction direction.

A check valve 78 arranged in the pressure line 38 prevents when the switching valve 19 is open, the opening pressure collapses by approx. 150 at in the line 58.

When the pump drive piston 13 has finished its suction stroke, actuated he by means of the cable 47 the limit switch 49, whereby the electromagnets 51, 52 are de-energized and the servo slides 53, 54 due to spring force (tension spring 59 resp. 60) are reset to their position II. In this position the servo slide the pressurized line 55 is connected to a pressure cylinder 61, which the resetting of the control slide 40 also causes it to be in position II. The same also applies accordingly for the control slide 20; the parts Hydraulic elements corresponding to 55, 61 are denoted here by 62, 63.

The previously pressurized line 41 is now connected to the return line 39 connected so that the pressure in the secondary line 58 initially drops sharply. The switchover valve 19 then closes by spring action and blocks the supply of pressure medium to the pump drive cylinders 12, 13, whereas for the pressure medium the path to the distributor drive cylinders 36, 37 via the lines 42 and 45 already free is. The distributor drive cylinders 36, 37 can thus perform their stroke, che the pump drive pistons 12, 13 start moving in the opposite direction can. The latter process can only occur when the distributor drive piston 36, 37 have finished their stroke and are in the cylinders 43, 44 and in the lines 42, 58 which has built up sufficient setpoint pressure to open the switchover valve 19. In this way, a safe sequence reversal of the pump piston and the distributor slide is possible guaranteed, so that there is no return or setback, including the conveyed goods as a result It is to be feared that the distributor slide valve is not closed or open.

It can occasionally happen that the drive cylinders 14, 15, 43, 44 is too much or too little pressure medium. To compensate for this here create is a feed line for each drive cylinder pair 14, 19 or 43, 44 64 and 65 provided, which via a common line 66 with the pressure line 17 communicates. In each feed line there is one f4and valve 67 resp. 68 and a safety valve 69 or 70 arranged. The feed of pressure medium is carried out by actuating the relevant island valve 67 or .68, whereas if there is an excess of pressure medium in the drive cylinders, there is a compensation the safety valves 69 and 70 takes place. The pressure medium can about a (to be opened beforehand) control tap 71 drain into a container 72, which is expediently is connected to the pressure medium containers 16, 29.

Another safety device of the system consists of one Safety valve 73, which is in a short-circuit connection 74 of the pressure line 17 with the return line 28 in front of the safety valve 19 and the control slide 20, 40 is arranged. In the event of malfunctions, which are usually caused by impermissible increases in pressure express in the line system, the safety valve opens 7.3 and allows a free Circulation of the pressure medium It is also a line surrounding the safety valve 73 75 is provided, in which a slide 76 with two positions I and II is arranged. The slide 76 can be actuated electromagnetically (item 77) from the switch cabinet so that a free circulation of the pressure medium (at position II of the slide 76) at any time even without actuating the safety valve 73, i.e. without prior Pressure increase in the line system can be achieved.

From Fig. 3 is now a practical embodiment for the implementation the path-dependent reversal of the pump pistons 10, 11 already mentioned above Actuation of limit switches by means of a cable can be seen. The cables are each composed of two parts 46a, 46b or 47a, 47b, each cable pulling into one Part made of an elastic material, preferably rubber, and the other part is made of plastic with steel cables. The two cable parts are each connected to one another by a releasable clamping connection denoted by 79. Through this an adjustment of the cable length and thus the pump stroke is possible.

The actuation of the limit switches designated by 48a and 49a in FIG. 3 takes place by touching a contact pin 80 with the respective contact 48b or 49b the limit switches 48a, 49a. The contact pin 80 is for this purpose on an in, attached to the center rotatably mounted lever 81, at the ends of which the cables 46a, 46b and 47a, 47b attack.

Claims (17)

A n p r ü c h e Piston pump for liquid to solid substances, in particular pulpy masses like concrete, with double-acting hydraulic drives for pump pistons and substance distributor, characterized in that by actuating a limit switch (48 or 49) through the pump piston or its drive piston (12 or 13) the Reversal of the pressure medium for the drive (36 or 37) of the respectively assigned Distributor and the pressure increase in the hydraulic drive of the distributor corresponding reversal of the pressure medium for the drive of the respectively assigned Pump piston is effected. 2. Piston pump according to claim 1, characterized by one on the drive piston (12 ban. 13) for the pump piston attached cable (46 or 47) for actuation of the limit switch (48 or 49). 3. Piston pump according to claim 2, characterized in that the rope train (46 or 47) to a part made of an elastic material, preferably rubber, and on the other hand made of an almost inextensible material, preferably plastic with steel core. 4. Piston pump according to one of the preceding claims, characterized in that that the stroke of the pump piston is adjustable. 5. Piston pump according to one of claims 2 to 4, characterized in that da3 the cable (46, 47) is divided and the adjacent ends of the cable parts are / are connected to one another by a (79) releasable clamping connection. 6. Piston pump according to claim 1, characterized in that the reversal the hydraulic drives (12, t3) for the Pui: -pen piston and the distributor (36, 37) is carried out by hydraulically actuated control spools (20 or 40), which in turn each pilot controlled by an electromagnetically operated control slide (53 or 54) are. 7. Piston pump according to claim 6, characterized in that by Activate the limit switch (48 or 49) simultaneously and in the same sense Switching the control slide (20, 40) for the pump piston and the distributor causes are. 8. Piston pump according to claim 6 or 7, characterized in that in the pressure line (17) in front of the hydraulically operated control slide (20) for the drive (12 or 13) of the pump piston a - preferably controllable - changeover valve (19) is arranged, which at a certain pressure in the drive cylinder (43 or 44) of the distributor releases the pressure line (17). 9. Piston pump according to one of the preceding claims, characterized by a short-circuit connection (74) pressure line-return line for the free Circulation of the pressure medium, in which connection a - preferably adjustable -Safety valve (73) is arranged. 10. @ Piston pump according to claim 9, characterized by a bypass line (75) for the safety valve (73), in which an electromagnetically operated Slide (7G) is arranged with a position (II) for the free circulation of pressure medium and a locking position (I). 11. Piston pump according to claim 6, characterized in that the electromagnetic actuated control slide (53, 54) and then also the hydraulically actuated Control slide (20, 40) can be switched in opposite directions, such that the pump cylinder works in the opposite direction - from the delivery line to the Pump hopper conveys back. 12. Piston pump according to claim 11, characterized in that the Reversal of the pump for conveying iio reversed sense is done by hand in such a way that an electrical switch is to be operated and that when the switch is released the pump is automatically switched back to normal pumping operation. 13. Piston pump according to claim 11, characterized in that the The pump is automatically reversed for delivery in the opposite direction, and depending on a certain pressure in the drive cylinder of the pump piston. 14. Piston pump according to one of the preceding claims, each with two pump pistons and distributors working in alternating rhythm as well as one corresponding number of drives for the same, characterized in that each between a pair of drive cylinders (14, 15) or (43, 44) There is a hydraulic connection (25 or 45) so that the one forward stroke executing piston is pressed into the other drive cylinder and causes the return stroke of the piston there. 15. Piston pump according to claim 14, characterized in that the IIub the drive cylinder (12, 13, 36, 37) is adjustable. 16. Piston pump according to claim 15, characterized in that in the A cylinder chamber in front of the drive piston is connected to the pressure line (17) Feed line (64 resp. 65) opens, which can be switched by hand by valves 67, 68). 17. Piston pump according to claim 15 or 16, characterized in that that in the feed lines (64, 65) for the drive cylinder pair (14, 15) of the Pump piston pair and for the drive cylinder pair (43, 44) of the distributor pair a safety valve (69, 70) is arranged in each case. L e r s e i t e