US 7,581,935 B2Granted

Device and method for controlling a thick matter pump

AssigneePutzmeister Concrete Pumps GmbH

InventorsWilhelm Hofmann, Stefan Höfling

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Abstract

The invention relates to a device and a method for controlling a two-cylinder thick matter pump comprising delivery pistons that are actuated in a push-pull manner by means of a hydraulic reversible pump (6) and hydraulic drive cylinders controlled by said pump. For each pressure stroke, the delivery cylinders (50, 50′) are connected to a delivery conduit (58) by means of a pipe junction (56). At the end of a pressure stroke, a reversal process of the reversible pump (6) and the pipe junction (56) is triggered. The aim of the invention is to obtain a targeted reversal of the reversal pump and the pipe junction, even when the deliverable quantity is varied, whereby the delivery cylinders are completely emptied, but also without pistons banging the ends of the cylinders. To this end, a computer-assisted reversal device is provided, said device comprising a measuring and evaluating routine for detecting the temporal displacement course of the piston along the path thereof between the two cylinder ends, by measurement and/or calculation, and for calculating a triggering time derived therefrom for the subsequent reversal of the reversible pump and the pipe switch.

Claims11

Dependent claims

A thick matter pump

with two conveyor cylinders (50, 50′) communicating via two end openings (52) in a material supply container (54), the conveyor cylinders (50, 50′) operated in counter stroke by a hydraulic reversible pump (6) via hydraulic drive cylinders (5, 5′) driven by the reversible pump, the hydraulic drive cylinders (5, 5′) each having a rod end and a base end;
with a hydraulically actuated pipe switch (56) provided within the material supply container (54), the pipe switch having an inlet and an outlet, which pipe switch inlet is alternatingly connectable to one of the openings (52) of the conveyor cylinders (50, 50′) freeing the respective other opening of the conveyor cylinders (50, 50′), and which pipe switch outlet is connected with a conveyor conduit (58), wherein the drive cylinders (5, 5′) are hydraulically connected at the base end via respectively one hydraulic conduit (11, 11′) to a connector of the reversible pump (6) and at their rod end are hydraulically connected with each other via an oscillating oil conduit (12);
with at least two cylinder switch sensors (20, 20′;
22, 22′) in predetermined separation from each other and spaced from the rod ends and/or base ends of the drive cylinders (5, 5′) and sensitive to the passage by of a piston (8, 8′) of the drive cylinder;
and
with a device (18) for controlling the thick matter pump responsive to the output signal of each cylinder switch sensor for reversing the reversible pump (5) and the pipe switch (56) after completion of a piston stroke,
wherein the device is a computer assisted reversing device including a measurement and evaluation routine for determining, by measurement or computation, the temporal displacement of the piston on its way between the two cylinder ends, as well as for computing therefrom a derived initiation time for the subsequent reversing of the reversible pump and the pipe switch.

4 more elements

A process for controlling a thick matter pump with two conveyor cylinders (50, 50′) communicating with two end openings (52) in a material supply container (54), the two conveyor cylinders (50, 50′) operated in counter stroke via at least one hydraulic reversible pump (6) and via hydraulic drive cylinders (5, 5′) driven by the reversible pump (6), the hydraulic drive cylinders (5, 5″) each having a rod end and a base end;

and with a pipe switch provided within the material supply container (54), the pipe switch having an inlet and an outlet, the pipe switch inlet alternatingly connectable to the openings (52) of the conveyor cylinders (50, 50′) for a conveyance stroke freeing the respective other opening, and the pipe switch outlet connected with a conveyor conduit (58), the process comprising:
(a) monitoring each conveyance stroke via at least two cylinder switch sensors (20, 20′;
22, 22′) at sensor positions spaced with predetermined separation from each other and from the rod and base ends of the drive cylinder (5, 5′),
(b) using the output of the cylinder switch sensors (20, 20′;
22, 22′) to measure or compute the position over time of the piston on its way between the rod and base ends of the drive cylinders.
(c) deriving therefrom the initiation time point for the respective next reversal process, and
(d) initiating at the initiation time point a reversing the reversible pump (5) and the pipe switch (56).

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/558,938Filed 18 Mar 2005
Priority: DE 10 2004 015 41626 Mar 2004
Published: US 2006/0245942 A12 Nov 2006
Granted: 1 Sep 2009
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

F04B 15/023
The fluids being viscous or non-homogeneous: supply of fluid to the pump by gravity through a hopper, e.g. without intake valve
F04B 7/0241
A common distribution member forming a single discharge distributor for a plurality of pumping chambers: and having an oscillating movement
F04B 9/1178
The movement of each piston in one direction being obtained by a single-acting piston liquid motor: the movement in the other direction being…
F04B 2201/0201
Piston parameters: position of the piston