Hydraulic conveyance

As Hydraulic conveying refers to a continuous conveying process in which the conveyed material is conveyed with the aid of a carrier liquid. The carrier liquid, usually water or salt solutions, serves as a fluid in this process. The process is used both in and outside the mining industry .

requirements

The conveyed material must be stored together with the carrier liquid in an elongated container, e.g. B. a conveyor trough or a pipeline, are moved from a starting point to the destination. Bulk goods with a small to medium grain size come into consideration as conveyed goods . Fibrous bodies with a low density can be conveyed more easily than heavy bodies with a smooth surface. The prerequisite for a conveyed item to be able to be moved in this way is that the conveyed item is insensitive to abrasion and water wetting. In addition, the density quotient between the material being conveyed and the carrier liquid must be small so that the particles being conveyed can move freely swimming at the speed of the carrier liquid. In order to achieve this, the specific weight of the material to be conveyed may only be slightly greater than that of the carrier liquid. In order to be able to move heavier particles with a carrier liquid, the flow speed must be increased. This leads to a high power consumption.

Main types

There are two main types of hydraulic delivery, flush delivery and pump delivery.

Flushing conveyance

With this type of construction, the material to be conveyed is moved with the carrier liquid in open conveyor troughs with the aid of gravity . The gutters must be laid with a longitudinal incline of about 6 degrees. The material to be conveyed is filled either at the beginning or along the conveying path into the trough open at the top, in which the carrier liquid flows. The mixing ratio of solid and carrier liquid must not be less than 1: 5. At the end of the conveyor line, the material to be conveyed and the carrier liquid are separated from each other again by separators. The water is pumped back to the feed point via a pipeline.

Pump delivery

Pump delivery is also known as hydraulic pipe delivery . In this design, the conveyed material with the carrier liquid is moved in a pipeline by means of a pump. With a smaller grain size, the conveyed material is fed in in front of the pump so that the conveyed material goes through the pump. The product and the carrier liquid are pressurized by the pump and pushed through the pipeline. In the case of coarser grains, the conveyed material is added to the conveying flow via a sluice. The goods to be conveyed may have a maximum diameter of 60 millimeters. It becomes problematic when conveyed goods with different densities, e.g. B. hard coal and lumps of rock , are simultaneously promoted hydraulically. Materials with different densities also have different sink rates . So that these substances cannot settle on the bottom of the pipe, the flow velocity must be correspondingly higher. The separation of the carrier liquid from the solids takes place at the end of the conveyor line in the same way as with the flushing conveyor. The recovered carrier liquid is then returned to the conveyor.

Funding directions

With hydraulic conveying, solid particles can be conveyed in a horizontal and also in a vertical direction.

Horizontal promotion

The horizontal conveyance can take place both by means of flushing conveyance and by means of pump conveyance. Normal centrifugal pumps are used to deliver pumps over distances of up to 2.4 kilometers . The conveyance takes place via pipes with a diameter of 200 to 250 millimeters. In the pipes, the large solid particles are moved back and forth between the upper and lower pipe walls as a result of the flow around the solid particles, without touching the pipe wall. The finer solid particles tend to settle on the bottom of the pipe. If the material to be conveyed is to be conveyed via a pipeline and the amount is inconsistent, an equalization device must be installed in front of the pump. This device consists of several containers in which the material to be conveyed is first collected and then fed evenly into the flow.

Vertical conveyance

The vertical conveyance takes place by means of pumps through pipes with the same diameter as with the horizontal conveyance. Simple mammoth pumps are used as pumps up to a lifting height of 150 meters . Multi-stage mammoth pumps are used for shafts with a depth of 400 to 600 meters. Hydrostatic pumps are used for even greater depths. These are long-stroke piston pumps with hydrostatic drive and hydraulic control. In some applications, pipe feeders were used as feed devices for the water-solid mixture at greater depths . So that the vertical conveyance can be used optimally, the water-solid mixture coming from the horizontal conveyance must be dewatered or equalized. This is necessary because the optimal water-solids ratio for vertical conveyance is 1: 3. With vertical conveying, the large particles do not even get to the pipe wall, so that there is no wear and tear. At the upper end of the conveyor line, the water and solids mixture is separated from one another in a treatment plant.

Areas of application

Hydraulic conveying is used in various areas. It is used in mining and tunnel construction to transport debris over long distances. This relieves the conventional shaft and route conveyance. Another area of application is the mining of gold-bearing rock with the help of pressurized water jets and the subsequent removal. In underground days , the process in combination was with the hydromechanical extraction used. Hydraulic conveying was also used when introducing backfill into old mine workings . About day one uses the pump delivery for transporting soil and coal. Hydraulic conveying is also used to convey the sand extracted in the open pit by means of backhoe excavators . Outside of mining, the flushing process is used in sugar factories to transport sugar beet.

Individual evidence

↑ ^a ^b ^c ^d ^e ^f Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining dictionary . 7th edition, Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l Heinz Pfeifer: conveyor technology . 5th improved edition, Friedrich Vieweg & Sohn, Braunschweig 1989, ISBN 978-3-528-44061-9 , pp. 318-319.
↑ ^a ^b ^c Heinrich Aumund , Fritz Mechtold: Lifting and conveying systems. Basics construction types applications. 5th completely revised and greatly expanded edition. Springer Verlag, Berlin / Heidelberg / New York / Berlin 2012, ISBN 978-3-642-49223-5 , pp. 171–175.
↑ ^a ^b ^c ^d ^e ^f Georg von Hanffstengel: The promotion of bulk goods . Volume I, Springer-Verlag Berlin Heidelberg GmbH, Berlin Heidelberg 1908, pp. 220-221.
^ Karl-Heinrich Grote (ed.), Jörg Feldhusen (ed.): Dubbel paperback for mechanical engineering. Twenty-second revised and expanded edition, Springer Verlag, Berlin Heidelberg New York 2007, ISBN 978-3-540-49714-1 , p. N 31.
↑ ^a ^b ^c ^d ^e ^f Bruno Eck: Technical fluid mechanics . 9th edition, Volume 2 Applications, Springer-Verlag Berlin Heidelberg, Berlin Heidelberg 1991, ISBN 978-3-540-53426-6 , pp. 215-218.
↑ ^a ^b ^c ^d Hydraulic conveying of hard coal and hydraulic shaft conveying from great depths . In: Commission of the European Communities (Ed.): Research books coal. No. 70, Luxemburg 1976, pp. 12-16.
↑ Hydromechanical coal extraction and hydraulic extraction II . In: Commission of the European Communities (Ed.): Research books coal. No. 63, Gebirgsdruckforschung Synthesis Report I of the Steinkohlenbergbauverein, Luxembourg 1974, pp. 33–38, 84–89.
↑ Reinhard Bauer: Failed innovations. Failures and technical change, Campus Verlag GmbH, Frankfurt / Main 2006, p. 160.
^ ^A ^b Heinrich Aumund, Fritz Mechtold: Lifting and conveying systems. Fourth, revised and expanded edition, Springer-Verlag Berlin Heidelberg GmbH, Berlin Heidelberg 1958, pp. 137–139.
↑ Hans Herrmann Nocke: Process for underground operation with hydraulic conveyance and system for carrying out the process . Patent specification from Ruhrkohle AG, July 14, 1988, publication number DE 3823863 A1.

[Quelle_1-1] ↑ ^a ^b ^c ^d ^e ^f Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining dictionary . 7th edition, Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .

[Quelle_2-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l Heinz Pfeifer: conveyor technology . 5th improved edition, Friedrich Vieweg & Sohn, Braunschweig 1989, ISBN 978-3-528-44061-9 , pp. 318-319.

[Quelle_6-3] Heinrich Aumund , Fritz Mechtold: Lifting and conveying systems. Basics construction types applications. 5th completely revised and greatly expanded edition. Springer Verlag, Berlin / Heidelberg / New York / Berlin 2012, ISBN 978-3-642-49223-5 , pp. 171–175.

[Quelle_4-4] ↑ ^a ^b ^c ^d ^e ^f Georg von Hanffstengel: The promotion of bulk goods . Volume I, Springer-Verlag Berlin Heidelberg GmbH, Berlin Heidelberg 1908, pp. 220-221.

[Quelle_3-5] Karl-Heinrich Grote (ed.), Jörg Feldhusen (ed.): Dubbel paperback for mechanical engineering. Twenty-second revised and expanded edition, Springer Verlag, Berlin Heidelberg New York 2007, ISBN 978-3-540-49714-1 , p. N 31.

[Quelle_5-6] ↑ ^a ^b ^c ^d ^e ^f Bruno Eck: Technical fluid mechanics . 9th edition, Volume 2 Applications, Springer-Verlag Berlin Heidelberg, Berlin Heidelberg 1991, ISBN 978-3-540-53426-6 , pp. 215-218.

[Quelle_7-7] Hydraulic conveying of hard coal and hydraulic shaft conveying from great depths . In: Commission of the European Communities (Ed.): Research books coal. No. 70, Luxemburg 1976, pp. 12-16.

[Quelle_8-8] Hydromechanical coal extraction and hydraulic extraction II . In: Commission of the European Communities (Ed.): Research books coal. No. 63, Gebirgsdruckforschung Synthesis Report I of the Steinkohlenbergbauverein, Luxembourg 1974, pp. 33–38, 84–89.

[Quelle_11-9] Reinhard Bauer: Failed innovations. Failures and technical change, Campus Verlag GmbH, Frankfurt / Main 2006, p. 160.

[Quelle_9-10] A ^b Heinrich Aumund, Fritz Mechtold: Lifting and conveying systems. Fourth, revised and expanded edition, Springer-Verlag Berlin Heidelberg GmbH, Berlin Heidelberg 1958, pp. 137–139.

[Quelle_10-11] Hans Herrmann Nocke: Process for underground operation with hydraulic conveyance and system for carrying out the process . Patent specification from Ruhrkohle AG, July 14, 1988, publication number DE 3823863 A1.