Abstract:
A thick-matter pump for producing a continuous thick-matter flow is described. The pump includes at least two pump units, which alternate in pumping and suction operation, a suction line with a charge-pressure device, which acts separately from the pump units for actively bringing about a thick-matter compression, a delivery line, and a switchover device for switching between the pump units. In a first operating state for conveying the thick matter, by way of the switchover device, at least one first pump unit is connected during pumping operation to the delivery line and at least one second pump unit is connected during suction operation to the suction line. In a second operating state, by way of the switchover device, at least one first pump unit is connected during suction operation to the delivery line and at least one second pump unit is connected during pumping operation to the suction line, and the charge-pressure device is switched to an inactive state.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a national stage of International Application No. PCT/EP2013/067806, filed Aug. 28, 2013, which claims priority from German Patent Application No. 10 2012 107 933.1 filed on Aug. 28, 2012 in the German Patent and Trademark Office, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a thick-matter pump for producing a continuous thick-matter flow, and to a method for operating a thick-matter pump for producing a continuous thick-matter flow. 
         [0004]    2. Related Art 
         [0005]    A thick-matter pump according to the prior art consists of two pump units which alternate in pumping and suction operation, a delivery line, a suction line with, attached thereto, a charge-pressure device, which acts separately from the pump units for actively bringing about a thick-matter compression, and a switchover device for switching between the pump units. In order to convey the thick matter through the delivery line, one pump unit is connected in pumping operation to the delivery line and one pump unit is connected in suction operation to the suction line, and the charge-pressure device compensates for the loss of efficacy of the sucking cylinder and compresses the thick matter. In this way the conversion process is bypassed and an interruption of the pumping process is thus avoided. 
         [0006]    Such a thick-matter pump is described for example in EP 1235 982 A1 or EP 1 599 672 A1. 
         [0007]    A continuous, directed thick-matter flow is produced in such pumps from the inlet end of the delivery line to the outlet end thereof. This signifies a considerable technical development, since, compared with the previous solutions, energy savings and also a considerable reduction of the power requirements are to be observed. 
         [0008]    In addition, wear is dramatically reduced, particularly in the pipelines. Lastly, the acceleration work is spared, which in conventional pumps has to be applied up to 30 times a minute in order to overcome the considerable loads in the lines. 
         [0009]    It is also not insignificant that loading and unloading acting on the lines and line carriers connected to the pump is spared, which causes uncontrolled movements and vibrations and thus leads to uncertainty with regard to work and to premature material fatigue. 
         [0010]    The thick matter to be pumped generally may not remain in the pump system, at least with long interruptions of the pumping process. These matters are often dispersions with water, which dry out and harden. In the most general of cases, concrete is pumped. The admixed cement and the water enter into a chemical reaction, which allows the thick matter to harden after just a short period of time. The concrete must therefore be removed from the entire system, from the suction line to the end of the delivery line, during a relatively long interruption or at the end of the pumping time. 
         [0011]    In the known thick-matter pumps, this is achieved by emptying the delivery line by introducing a separating element, for example a sealing rubber ball, into the delivery line, after which a water column or a compressed air cushion is pressed by means of the pump unit in the direction of the outlet of the delivery line, such that the content is emptied via said outlet and the line can be cleaned. 
         [0012]    However, the necessary disposal of the concrete/water mixture at the outlet end of the delivery line may be undesirable. In these cases the use of the aforementioned, otherwise very advantageous thick-matter pump systems is then not readily possible. 
         [0013]    Another problem arises also from the nature of the thick-matter concrete. In order to be able to pump concrete, suitable recipes must be followed. Nevertheless, separation occurs, such that partial volumes of the composition are no longer reproduced. Compression and wedging of the material lead to “blockages”. 
         [0014]    It is indispensable for practical use to overcome such problems, particularly when pumping concrete. 
       SUMMARY 
       [0015]    The present disclosure describes a pump system that overcomes the above-mentioned problems. 
         [0016]    Generally, the thick-matter pump for producing a continuous thick-matter flow includes at least two pump units which alternate in pumping and suction operation, a suction line with a charge-pressure device which acts separately from the pump units for actively bringing about a thick-matter compression, a delivery line, and a switchover device for switching between the pump units, wherein, in a first operating state, by way of the switchover device, at least one first pump unit is connected during pumping operation to the delivery line and at least one second pump unit is connected during suction operation to the suction line. In accordance with the disclosure, in a second operating state, by way of the switchover device, at least one first pump unit is connected during suction operation to the delivery line and at least one second pump unit is connected during pumping operation to the suction line, and the charge-pressure device is switched to an inactive state. 
         [0017]    The first operating state is understood to mean the operating state in which the matter is pumped through the delivery line in the direction of the outlet end thereof. This is regular pumping operation, in which the thick-material volume, for example the concrete volume, is pumped to the point of destination. 
         [0018]    The second operating state is the operating state in which the delivery line is emptied. Here, the delivery line is emptied by reversing the switchover device by way of the two pump devices. In particular the delivery line is pumped empty. Switching to and fro between the first and the second operating state may also loosen a “blockage” in the delivery line and may thus enable regular pumping operation again in the first operating state. 
         [0019]    In accordance with the disclosure, it may be significant in the second operating state that the charge-pressure device is switched to an inactive state in order to allow a problem-free reversal of the pumping action. 
         [0020]    The position of a slide of the switchover device for rerouting between the first and the second operating state is, in one embodiment, reversible. In other words, it is possible to switch between the two operating states by the reversed operation of the slide of the switchover device, that is to say an operation phase-shifted by 180° in the second operating state compared with the first operating state. However, the charge-pressure device is switched to an inactive state in the second operating state, whereas it is used in the first operating state to actively bring about the thick-matter compression. 
         [0021]    The running direction of at least a first and a second pump unit is, in certain embodiments, reversible in order to switch between the first and the second operating state, wherein the reversal can, in some embodiments, be performed by switching the running direction of the respective drive cylinder of the respective pump units. 
         [0022]    It is efficient to design the charge-pressure device such that it can be switched to an inactive state by connection to a storage container, wherein the charge-pressure device is, in some embodiments, connectable to a storage container by opening a slide gate valve. 
         [0023]    The charge-pressure device, in various embodiments, includes a drive cylinder/delivery cylinder unit. 
         [0024]    The charge-pressure device can thus be switched to an inactive state in that the piston of the delivery cylinder of the charge-pressure device closes the outlet end thereof and remains there in the second operating state. The charge-pressure device is thus prevented from lowering the pump efficiency in the second operating state. 
         [0025]    Mechanically, hydraulically, pneumatically or electrically actuatable switching elements for influencing the function of the pump units and the charge-pressure device are, in certain embodiments, provided, wherein the signals for actuation of the switching elements can be interrupted. 
         [0026]    In the second operating state, the thick-matter content of the delivery line, the pump units and the suction line can be pumped into a storage container. The system can thus be emptied reliably into an easily accessible region. 
         [0027]    A line extension can be connected to the inlet end of the suction line, and in some embodiments, within a storage container. Here, the content of the delivery line can be pumped via the line extension in the second operating state. 
         [0028]    In emergency operation, a first pump unit is advantageously connectable in pumping operation to the delivery line and a second pump unit is advantageously connectable in suction operation to the suction line, without switching on the effect of the charge-pressure device. As a result of this embodiment of the present disclosure, a reliable pumping operation can be achieved even in the event of failure of the charge-pressure device. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0029]    Embodiments of the present disclosure will be explained in greater detail on the basis of and the drawings, 
           [0030]      FIG. 1  schematically shows a thick-matter pump of the present disclosure in the first operating state; 
           [0031]      FIG. 2  schematically shows the thick-matter pump of  FIG. 1  in the second operating state; 
           [0032]      FIG. 3  schematically shows the thick-matter pump of  FIG. 1  in an alternative embodiment of the second operating state; and 
           [0033]      FIG. 4  schematically shows the use of a thick-matter pump when fighting a fire. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    The embodiments shown in the figures will be described in detail hereinafter. Here, like reference signs denote similar or like components and a repeated description thereof can be spared so as to avoid redundancies. 
         [0035]      FIG. 1  illustrates a thick-matter pump in the first operating state, that is to say the situation normally occurring when pumping concrete. 
         [0036]    Here, a pumping device for producing a continuous thick-matter flow is illustrated in  FIG. 1 . A first pump unit  1  is connected via a switchover device  7  to a delivery line  5 . A second pump unit  2  is connected to the suction line  4  and a charge-pressure device  3  fitted thereon. The necessary connections of the pump units  1 ,  2  can be produced alternately via the respective position of a slide  17  of the switchover device  7 . 
         [0037]    A storage container  9  flange-mounted to the suction line  4  can be separated from the suction line  4  by means of a slide gate valve  8 . 
         [0038]    The delivery line  5  is typically a delivery line system consisting of piping, a distributor mast or fixedly laid lines at a construction site. 
         [0039]    The first pump unit  1  pushes thick matter into the delivery line  5 . When the slide  8  is open, the second pump unit  2  and the charge-pressure device  3  suck thick matter from the storage container  9  until the piston of the delivery cylinder  12  of the sucking pump unit  2  overruns the switching point  10 . 
         [0040]    The switching point  10  prompts the closure of the slide  8  and launches the fully filled charge-pressure device  3 , which pushes thick matter against the closed slide gate valve  8  and thus into the sucking pump unit  2  until this is largely or completely full, the thick matter located therein is compressed, and the delivery piston  12  has reached the end position thereof with the switching point  11 . 
         [0041]    The switchover device  7  is actuated by this switching point  11 . The first pump unit  1  is now connected to the suction line  4  and the second pump unit  2  is connected to the delivery line  5 . 
         [0042]    During this phase, the charge-pressure device  3  pushes further directly into the delivery line  5  in order to close a delivery gap that has formed. 
         [0043]    As soon as the charge-pressure device  3  is completely emptied and said device has overrun the switching point  6 , the slide gate valve  8  opens. The charge-pressure device  3  is switched and, together with the pump unit  2  then in suction operation, sucks thick matter from the storage container  9 . The described operating cycle then starts again from the beginning in the first operating state. 
         [0044]    The charge-pressure device  3  corrects the interruptions of the thick-matter flow appropriately, such that a continuous thick-matter flow is produced in a direction, specifically the delivery direction. 
         [0045]      FIG. 2  shows the thick-matter pump of  FIG. 1  in the second operating state, which is used to empty the delivery line  5  or to apply an oscillating thick-matter movement in the delivery line  5 . 
         [0046]    The switchover device  7 , via which the pump units  1 ,  2  are connected, is switched over or reversed. The first pump unit  1 , which is in suction operation, is thus now connected to the delivery line  5 . The second pump unit  2 , which is in pumping operation, is connected accordingly to the suction line  4 . 
         [0047]    So that the thick-matter content located in the second pump unit  2  can pass via the suction line  4  into the storage container  9 , the slide gate valve  8  must be open. 
         [0048]    At the same time, together with the reversal of the switchover device  7 , the charge-pressure device  3  must be switched to an inactive state for efficient operation of the thick-matter pump in the second operating state. To this end, in the shown embodiment, the delivery piston  14  of the delivery cylinder of the charge-pressure device  3  is to be moved to the outlet  18  and is to be held there during operation of the thick-matter pump in the second operating state in order to close the outlet end  18  of the delivery cylinder of the charge-pressure device  3 . However, the charge-pressure device  3  is already switched to an inactive state by the opening of the slide gate valve  8 . 
         [0049]    The delivery cylinder of the charge-pressure device  3  is thus emptied and no longer has to be taken into consideration during cleaning procedures. 
         [0050]    In order to achieve a further emptying of the delivery line  5 , the switchover device  7  continues to be operated analogously, but phase-shifted by approximately 180° in relation to operation in the first operating state. Accordingly, in the next process step, the second pump unit  2 , which is then in suction operation, is now connected to the delivery line  5 . The first pump unit  1 , which is in pumping operation, is connected accordingly to the suction line  4 . The entire delivery line  5  can be pumped empty in this way. 
         [0051]    The inlet opening of the suction line  4  in the storage container  9  has a connector  15  for an extension line  16 , via which the content of the delivery line  5  can be conveyed further, for example into a truck mixer or a recycling facility. 
         [0052]    The action of the charge-pressure device  3  is cancelled via switching elements. These can be actuated mechanically, hydraulically, pneumatically or electrically and also by light and magnetic waves. In some cases it may be advantageous to design the signals for actuation of the switching elements such that said signals can be interrupted. 
         [0053]    The pump system  1 ,  2 ,  3  inclusive of the suction line  4  and the delivery line  5  should be emptied with relatively long interruptions or at the end of the pumping operation. Should this not be possible via the outlet end of the delivery line  5 , the content of the pump system inclusive of the delivery line can be pumped at least into the storage container  9 . If the thick-matter volume in the system formed of delivery line  5 , pump system  1 ,  2 ,  3  and a suction line  4  is not too large, the storage container  9  is generally able to receive the quantity. There, the thick matter can remain in the short term, can be treated or can be disposed of. 
         [0054]    If the thick-matter volume is greater, an extension  16  can be attached at the inlet end  15  of the suction line  4  in the storage container  9 , whereby the extension allows the content to be pumped into a larger vessel, for example a provided truck mixer. 
         [0055]    For the purpose of removing what are known as “blockages”, a continuous thick-matter flow may be inhibiting. A temporary switchover from pumping operation to suction operation and vice versa may be necessary, that is to say a brief switchover from the first operating state into the second, and vice versa. The corresponding connections of the pump units  1 ,  2  to the delivery line  5  or the suction line  4  should therefore be switchable, without being influenced by the action of the charge-pressure device  3 . 
         [0056]    A temporary switchover of the pump units  1 ,  2  should be possible at each position of the pistons  12 ,  13  in the delivery cylinders. 
         [0057]    In an alternative embodiment, which is shown in  FIG. 3 , the switchover device  7  retains its position and phase as in the first operating state. The functions of the pump units  1 ,  2  are reversed by reversing the running direction of the drive cylinders  21 ,  22  of the pump units  1 ,  2 . In other words, the operation of the pump units  1 ,  2  in the second operating state is reversed or phase-shifted by approximately 180° compared to the first operating state. 
         [0058]    The content of the first pump unit  1 , which is now located in pumping operation as a result of the reversal of the operation of the pump unit  1 , is still connected to the suction line  4 , whereby the content is pushed back into the storage container  9  by the open slide gate valve  8 . 
         [0059]    The second pump unit  2  is accordingly offset by the switch into suction operation and remains connected to the delivery line  5 , whereby this is sucked off. 
         [0060]    Due to the alternating pumping and suction operation of the pump units  1 ,  2 , the thick matter located in the second pump unit  2  passes via the suction line  4  and the open slide  8  likewise into the storage container  9 . 
         [0061]    In the case of this process as well, the charge-pressure device  3  is switched to an inactive state, in that the delivery piston  13  of the charge-pressure device is moved to the outlet end  18  of the delivery cylinder of the charge-pressure device  3  and is held there in the second operating state in order to close the outlet end  18 . 
         [0062]      FIG. 4  schematically shows a use of a mobile thick-matter pump when fighting a large fire in industrial operation or when cooling a damaged electricity power station. With such uses of the mobile thick-matter pump, it is important to apply as much extinguishing agent and/or cooling fluid as possible in the shortest time selectively to the fire source and/or the area to be cooled, without endangering people in the process. The use of the mobile thick-matter pump for such uses is therefore advantageous because the mast of the mobile thick-matter pump can be moved selectively and the discharge location of the extinguishing agent and/or cooling medium at the end of the mast is distanced far from the respective operator of the mobile thick-matter pump. 
         [0063]    Accordingly, by way of the connector  15  for the extension line  16 , a further line  26   a  can be connected thereto for connection to an extinguishing agent reservoir and/or coolant reservoir arranged at a further distance. The thick-matter pump can be used in this way as an extended use possibility for extinguishing burning objects or for cooling objects to be cooled, wherein it can output an uninterrupted jet and a high volume with sufficient accuracy. Due to the structure of the thick-matter pump with the charge-pressure device  3 , the volume flow achieved here is uniform and much higher (up to 50%) compared with a device of equal dimensions without charge-pressure device. Furthermore, due to the constant flow, a higher target accuracy can be achieved, since the mast does not perform any unpredictable see-saw movements. 
         [0064]    If a coolant is sprayed here, for example onto a damaged power plant, this coolant must often also be sucked up again. The coolant or the extinguishing agent typically collects on the floor, in hollows or in chambers arranged low down. The coolant may become loaded with different materials, for example with radioactive isotopes or with material dissolved by the coolant. During suction, sand, wall fragments or other solid and suspended bodies are also sucked up. 
         [0065]    The thick-matter pump proposed here can again pump off the coolant loaded with the respective materials, in particular the harmful substances and the solid and suspended bodies, via the mast of the mobile thick-matter pump. In particular the loaded coolant is pumped into a wastewater reservoir  25  by means of the line  25   a  likewise attached to the extension line  15 . The respective operator does not come into contact with the wastewater during this process. 
         [0066]    The switchover between the wastewater reservoir  25  and the coolant or extinguishing agent reservoir  26  is achieved in the shown exemplary embodiment by corresponding slides  24 , which can each open just one line  25   a ,  26   a.    
         [0067]    Due to the insensitivity of the thick-matter pump with respect to suspended materials conveyed with the respective fluid, a repeated use of the respective coolant fluids is also conceivable in order to reduce the overall volume of the loaded material. To this end, liquid from the two reservoirs  25 ,  26  can then be fed and pumped off again alternately.