Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B15/00—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts
  • F04B15/02—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts the fluids being viscous or non-homogeneous
  • F04B15/023—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts the fluids being viscous or non-homogeneous supply of fluid to the pump by gravity through a hopper, e.g. without intake valve
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B7/00—Piston machines or pumps characterised by having positively-driven valving
  • F04B7/0038—Piston machines or pumps characterised by having positively-driven valving the distribution member forming a single inlet for a plurality of pumping chambers or a multiple discharge for one single pumping chamber

Definitions

• the invention relates to a thick matter pump with at least two pump units alternating in pumping and suction operation, a delivery line, a suction line and a changeover valve for switching between the two pump units, the changeover valve being a pump unit in pumping operation with the delivery line and a pumping unit in suction operation with the suction line combines.
• the main characteristic of such pumps is that at the end of a stroke, at least during the changeover time of the changeover valve, the pumping work is interrupted. Further delays result from the properties of the medium to be pumped. In the case of concrete, the most pumped medium, the suction stroke can often result in insufficient filling of the cylinder. It is therefore necessary to compress the medium before pushing the flow.
• a particularly negative effect, which influences the pumping process, is that during the switching process, the valve position allows the thick matter to flow back from the delivery line into the suction cylinder, which is not completely filled, or even into the storage container.
• German patent DE19503986 A basic solution to the problem is described in German patent DE19503986.
• the two pumping units one Form a two-cylinder thick matter pump, and are connected by means of a changeover device alternately to the container or the delivery line and their delivery pistons alternately perform a suction and a pressure stroke, controlled so that the average piston speed during the suction stroke is at least temporarily greater than during the pressure stroke.
• the changeover device at least temporarily separates the two delivery cylinders from the storage container and connects the latter together to the delivery line.
• the tube switch only switches after the pre-tension pressure has been applied.
• One end of the pipe switch is constantly connected to the suction line section leading away from the storage container, whereas the delivery line is constantly connected to the cavity of the pipe switch housing.
• the prestressed thick material now comes into contact with the pressurized thick material in the pipe switch housing. This process does not lead to an oscillation in the delivery column, since the preload is preferably at the pressure level in the delivery line and therefore the thick matter does not sag in the delivery line.
• the second pumping unit takes over the pumping operation.
• the second pump unit is then connected to the storage container by means of the pipe switch and opening the gate valve. The cycle starts again with the switching of the pump units.
• the proposal which can be found in DE 19957337.9, solves all the shortcomings that occur in the proposals for producing a continuous thick material stream.
• This proposal uses known control methods for the drive cylinders and changeover devices and solves the problem of pretensioning in the delivery cylinders in that a boost pressure device is installed in the area of the suction line. This ensures that at the end of the suction stroke the cylinder is fully filled and the content is biased to the pressure level of the delivery line.
• the object of the invention is now to develop a method which offers suggestions such as e.g. are described in DE 19957337.9, simplified and further developed.
• the invention solves this problem with the means of claim 1, characterized in that the boost pressure device is connected to the delivery line in the area of the switchover phase.
• the boost pressure device By connecting the boost pressure device to the delivery line, it is possible to use the delivery capacity of the boost pressure device in order to bridge the interruption of the delivery flow in the delivery line that occurs during the switchover phase. Of course, it must be ensured that the boost pressure device has sufficient filling to provide the compression and bypass performance.
• the changeover and connecting means can be accommodated in the concrete storage container or in a separate slide housing.
• the latter variant is more expedient, which is why the following section deals primarily with changeover valves which are accommodated in a separate slide valve housing.
• This valve housing will be designed so that it has at least four openings, two of which are connected to the delivery cylinders, one with the suction line and one opening with the pressure line.
• the entrances and exits are to be installed in such a way that a suitable changeover device can make the necessary connections.
• An obvious design of the changeover device that can connect the boost pressure device and the delivery line is a pipe switch.
• a connection of the boost pressure device to the suction line is conceivable, so that the pipe switch can have the known shape of an S-pipe.
• the boost pressure device is connected to a special access to the pipe switch. In this case, it is advantageous to connect the connection for the boost pressure device to the pipe switch on the opposite side of the suction line.
• the axis through both connections is the axis of rotation of the pipe switch.
• connection of the boost pressure device to the delivery line takes place in the case of a pipe switch designed in such a way that an access to the delivery line is established in a central position between the two delivery cylinders.
• the easiest way to do this is for the glasses plate to have a corresponding one Has cutout and projection so that the opening of the pipe switch in this position can release material into the access to the pressure line, usually this is the sliding housing.
• rotary vane for example, which can be designed as a double-wing slide.
• Such a slide system housed in a housing as described above, can alternately form a suction and pressure channel for each feed cylinder. If the slide is brought into a central position, it forms a double channel that connects the boost pressure device to the delivery line. Since such slides can be kept very slim, an ideal connection between the pressure line and the boost pressure device is possible.
• the duration of the connection In order to accomplish the main concern of the invention, namely the maintenance of the thick matter flow during the changeover phase, it is important: the duration of the connection, the pressure that the charging device has, the amount that the boost pressure device has to provide and the switching times of the individual steps of the changeover.
• the pressure of the charging device must e.g. correspond at least to the pressure in the delivery line.
• the output during the switchover phase should cover the volume loss during this.
• the parameters and an exact coordination of the desired sequence depend crucially on the switching times. For example, it may be advisable to set the time for the start of the switchover phase shortly before the end of the suction stroke, so that the middle position of the slide and thus the connection between the boost pressure device and the delivery line is reached before the suction and pressure stroke is over.
• the switching from the middle position is actuated as soon as the printing cylinder is switched on and starts its work.
• the starting point is a slide valve housing (12) which has four openings.
• the two feed cylinders (1 + 2) are connected to two entrances. Another opening is occupied by the suction line (5) with the boost pressure device (8) and the reservoir (9).
• the pressure line (7) opens on the opposite side.
• the connections are made by a changeover device (6), for example a rotary slide valve, which alternately forms a pressure (14) and a suction channel (15) in the housing for each delivery cylinder.
• the changeover device (6) connects the pump cylinder (2) to the delivery line (7) and the reservoir (9) via the open slide (10) and the suction line (5) to the suction cylinder (1).
• the boost pressure device (8) is connected to the suction line (5) and also draws in thick matter from the storage container. Since the suction side has a very low pressure level, the changeover device (6) with the pressure difference between the suction side and the pressure side is additionally pressed against the stops (13). In Figure 2, the suction piston (3) has reached the switching point (a). By this time, the boost pressure device has also sucked in its maximum volume.
• the storage container (9) is separated from the suction line (5) by closing the slide (10).
• the boost pressure device (8) begins to push and presses material into the cylinder (1) via the suction line (5) and compresses it at the same time.
• the pressure piston (4) presses thick matter into the delivery line (7) at the desired speed and pressure.
• the boost pressure device (8) takes over the supply of the delivery line (7) with regard to quantity and pressure for a short time.
• the thick matter can only escape into the delivery line (7) because the delivery cylinder (2) is closed by the delivery piston (4) and the cylinder (1) is not receptive due to the compressed thick matter.
• a signal at switching point (c) causes the two delivery cylinders (1) and (2) to be switched over.
• Switching the changeover device (6) reduces the delivery of the boost pressure device (8) into the pressure line (7), at the same time the delivery of the cylinder (1) is increased. (Fig. 5).
• the changeover device has been fully converted, the cylinder (1) ensures full pressure and volume supply for the pressure line.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Reciprocating Pumps (AREA)
• Control Of Positive-Displacement Pumps (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Power Steering Mechanism (AREA)
• Fuel-Injection Apparatus (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=31502216

Family Applications (1)

Country Status (5)

Cited By (3)

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Family Cites Families (4)

• 2002
  • 2002-08-31 DE DE10240256A patent/DE10240256A1/de not_active Withdrawn
• 2003
  • 2003-08-26 WO PCT/EP2003/009418 patent/WO2004025119A2/fr not_active Ceased
  • 2003-08-26 AU AU2003283233A patent/AU2003283233A1/en not_active Abandoned
  • 2003-08-26 EP EP03775139A patent/EP1599672B1/fr not_active Expired - Lifetime
  • 2003-08-26 AT AT03775139T patent/ATE386882T1/de not_active IP Right Cessation
  • 2003-08-26 DE DE50309228T patent/DE50309228D1/de not_active Expired - Lifetime

Non-Patent Citations (1)

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