RS20090035A - FILTER PIPE - Google Patents

Abstract

The invention relates to a filter tube, in particular for draining water-bearing soils/layers of soil.

Description

KNOCH, KERN&CO.(AT/AT)

FERDINAND-JERGITSCH-STRASSE 15

A-9020 KLAGENFURT (AT)

The proposed invention relates to a filter pipe, especially for dewatering primarily soil/subsoil layers.

Filter pipes are usually made as pipes with holes or slots made of artificial plastics or steel. The ends of the filter tubes facing each other are screwed and connected to each other, for example, via suitable threads. They are placed along the area of water courses - sources in the corresponding wells in the ground, in order to carry out the drainage-drying of certain soil, i.e. the lower layers of the soil. Individual filter pipes can also be installed as conduits by inserting them into conventional well pipes or they can be placed within standard pipe conduits (for example, for drainage or tunnel dewatering). Analogously, they can also be used at pumping stations for emptying ponds or swamps.

In connection with this problem, the so-called filters made of glued pebbles are generally known. For these filters, gravel is mixed with epoxy resin and this mixture is placed over the entire outer inlet surface of the filter tube. The glue partially joins the parts and ends of the gravel grains, so that a special coating or coating on the filter pipe is obtained with the possibility of groundwater passing in the radial direction into the drainage pipes. This creates a problem, because pieces of gravel fall off in the middle of vibrations (grains of gravel) from the filter lining, as well as particles of the surrounding material.

- earth, pass through the slits of the filter tube and get inside.

Filter pipes can also be used in brown coal extraction. The brown coal deposits in the west of Germany contain, for example, 50% water, so that huge amount of water has to be pumped out, before mining the brown coal. For drainage purposes, several wells must often be created around the working zone for daily needs. Well pipes with filter pipes are placed in these wells, either lying or hanging. It is especially important for pipes, which are installed as hanging, that they must have significant strength in a certain part - resistance to stretching, which cannot be made possible through the already mentioned multiple threaded connection. Aggravating circumstances are that deep wells must often be dug due to the specific situation and accordingly many filter pipes must be connected to each other. This increases the existing problem of achieving satisfactory tensile strength for individual pipes.

The task of the invention is basically to create a filter pipe, particularly suitable for use in constructed wells, i.e. for dewatering the soil/bottom layers of the soil, for example, at a brown coal deposit, i.e. during the construction of a tunnel, which achieves: ease of installation and assembly, high performance and drainage power, and at the same time the pipe has high tensile strength.

In accordance with the invention, at least three parts of the filter tube are included, which are placed one after the other in the direction of the longitudinal axis of the filter tube, namely: one first end part of the tube with one connecting part for direct or indirect

connection with another further filter or well pipe,

at least one filter segment with at least one filter part, which it owns

possibility of passage of water in the radial direction on the axis of the filter tube,

one other end part of the pipe with one connecting part for indirect or indirect

connection with another further filter or well pipe.

The end parts of the filter pipes enable the connection of another further filter pipe via the existing connector part. A permeable or flow filter segment is placed between the end parts of the pipe and is used to drain water.

The end parts of the pipes, which are normally impermeable to water, must be made of materials with high tensile strength. For this purpose, the invention envisages the insertion of glass fibers in order to strengthen the artificial mass intended for the production of pipes, especially duroplastic artificial mass from the group: unsaturated polyesters, epoxies, vinyl esters, polyurethane with a single weight part of 5 to 50 (5-15; 30-50) % - glass fibers with a length of 5 to 75 (25-50) mm and a mean diameter (d 50) of 8 to 20 (10-14) um. (Possible alternative threshold values are given in parentheses.)

In order to make the entire filter tube with high tensile strength, it is further envisaged that at least one filter segment is foreseen and made with several elements in the form of spaced rods, which are placed next to each other parallel to the longitudinal axis of the filter tube, and which must have a tensile strength > 50 MPa (for example > 100 or > 250 MPa with a typical upper limit up to 300 MPa or 280 MPa ). Next to these or between these rod-shaped elements (rod elements) a filter part is provided through which water penetrates. This filter part (filter body) must have particular resistance and strength due to the underpressure, which is created due to the high suction power produced by the flow pump installed in the well. The rod-shaped elements are responsible for the general strength, and especially for the tensile strength.

Overall, the inner middle part of the filter tube, which represents the filter segment, has a cage-like structure.

Based on the compromise between the ability to carry the filter tube and at the same time achieving the optimal mechanical load distribution throughout the tube, the rod elements can be arranged rotationally symmetrically in relation to the longitudinal axis of the filter tube.

At the same time, it is possible, which is a consequence of the cylindrical shape of the filter tube, to make this filter part in the shape of an arch - bulging. Each of these filter parts has the form of a cylindrical segment. The filter part can also be radially pulled out via rod elements (pulled - stretched rods). It can also be ensured by the extent of passage, so that, for example, a cylindrical shape is formed and at the same time it is covered with the aforementioned rod elements.

It is also possible to form individual, discrete filter parts between the rod-shaped elements.

In addition to the mentioned rod elements, a flow filter part can also be formed from other elements, rotationally symmetrical in relation to the longitudinal axis of the filter tube, especially it can be in the form of strips, which flow parallel to the longitudinal axis of the filter tube.

The filter part (between the rod elements) can be identically constructed in all variants. It is also defined and found within the scope of the attached invention and according to the invention the filter part can be made in different ways. For example, it can be - in some cases of application - of great help, when providing a filter part with different porosity or with a different size of pores or capillaries, which ensure good water conduction. At the same time, the specificity of the soil must be taken into account, so that, for example, water can be drained from fine clay soil in the same way as from coarse-grained soil material.

Elements in the form of rods must be firmly connected to other parts of the filter tube through a specially designed form, which are attached to the rod elements in the longitudinal direction of the filter tube. For example, rod elements can also be glued. Suitable glues for this are epoxy solid glue and methyl acrylic glue. In the same way, it is possible to do it with a finished pipe, which would be cut to the length of the rod elements, so that the filter pipe consists of a one-piece basic body.

As a rule, the filter tube consists of only three parts (two end parts and the filter segment). In this case, the rod-shaped elements must be immediately fixed and connected to the end parts of the filter tube.

In doing so, the rod-shaped elements can be connected to the corresponding parts of the filter tube in different ways, for example, they can be glued or welded. It is also possible to connect or fasten with pins, anchors, clamps, etc.

The aforementioned solutions, in which the filter segment has end parts as adjacent zones and has axial permeability, end parts with open slits in the axial direction are performed, in which rod elements are placed in the corresponding end part and are attached, as already explained in the previous part. This will be shown in the following examples of execution with the help of drawings. The rod-shaped elements can be attached compactly to the outer side of the circumferential surface of the end part of the filter tube. In this case, the outer diameter of the filter tube in the area of the end part is the same as the outer diameter of the filter tube in the area of the filter segment.

Rod elements can also be shaped radially inwards or outwards.

These rod-shaped elements, which should have a high tensile strength in the indicated values, consist of, for example, duroplastic, reinforced with fibers, especially with glass fibers, made of artificial plastics such as: unsaturated polyester, epoxy, vinylester, etc. Thermoplastic materials such as polyethylene, polypropylene or polyamide can also be used for production. They can be made from the same material that is used for

making the end parts of the filter tube.

The filter part between the rod elements can be filled with a loose granular agent, whereby the distance between adjacent grains of the agent is set to a defined value of water permeability through the filter, and the grains are joined together using a special glue.

The filter part formed between adjacent rod elements must have - in the radial direction - a certain strength, which must correspond to the strength of the basic rod-shaped elements; the filter part can also be designed with elements drawn inwards and/or outwards.

Granular means for filling consists of at least one material from the group: kvare, quartz sand, CaCCh, dolomite, granite, porous glass, expanded clay. The grain size in the bulk material is selected according to each specific application. Their size ranges, for example, between 1 and 10 mm or 1 and 7 mm. Other possible grain sizes lie between 2 and 5 mm, and may, for example, be between 3 and 5 mm.

The grains from the bulk material are glued, for example, by means of artificial (synthetic) resin (epoxy resin or special duroplastic resin). The gluing of grains, that is, the formation of the glued part of the filter, is performed in such a way that it does not worsen or reduce the desired permeability of water through the filter. Therefore, a certain grain surface structure has mostly only one application, so that the space between the grains remains constant with a certain porosity.

The filter part may have, for example, a certain total free porosity between 10 and 70% by volume, for example between 20 and 50, or between 25 and 40% by volume.

In order to determine the required porosity, the following simple test can be carried out: the volume of the test body is geometrically calculated (for example, a cuboidal form) and the total volume (V[) of the tested piece is determined. This volume ( Vi ) is put in proportion to the volume ( V2 ), which is determined by the amount of displaced water, when the test body is completely submerged in water at atmospheric pressure [ free porosity = (Vi - V2) • 100/ Vi ].

The mechanical characteristics of the filter part can be defined through a bending test in accordance with the ISO 178 standard. The corresponding bending values should lie within the limits of 2 - 10 MPa, whereby a value of 3 - 6 MPa is most often satisfactory.

In the following part, possible procedures for the production of a filter tube according to the invention are described.

Starting from a known pipe made of artificial plastic mass reinforced with glass fibers, such as, for example, described in the document EP 360758 A2 or in the document CH-684326 A5, which will be cut into partial segments in the next production cycle.

At the end of each partial segment, an end part with special notches is provided, which are open towards the free end of the end part. These notches can be cut with a saw. Primarily, the notches are evenly and symmetrically (rotationally symmetrical) distributed along the entire circumference of the pipe segment.

The second pipe segment prepared in this way will be connected at a certain distance from each other, positioned with one mandrel, so that the end part with notches lies at a defined distance directed towards the first part and towards its notches.

Then the elements in the form of rods, which can be made from the same raw material from which the pipe segments are built, are placed so that each one with its end part is inserted into the corresponding notches, so that each rod is placed parallel to the longitudinal axis of the pipe elements. The elements in the form of sticks are now glued into the corresponding notches with the help of a special glue based on epoxy resin (or polysocyanate or acrylate). Profiles (rods) can also be made of artificial resin, for example, of epoxy resin, reinforced with pultruded glass fibers.

In this way, a kind of cage is formed in a cylindrical shape, built from elements in the form of sticks, which are arranged with a certain distance from each other until the aforementioned cylindrical circumferential surface with notches is filled.

The built-in part thus formed is now connected and placed on a cylindrical core, whereby the outer diameter of the core corresponds to the inner diameter of the newly formed built-in part. In other words: the inner surface of the tube segment and the rod-shaped elements meet and pass over the circumferential surface of the core. After this, the core part and the newly formed fitting part are placed in one forming tool, which can be heated. The forming tool has a hollow cylindrical shape, with the inner diameter having two steps. In one part with a smaller diameter, which ends with the lower closed end of the forming tool and which has an inner diameter corresponding to the mating diameter of the newly formed fitting. This part of the tool serves to accept and hold the end part of the newly formed fitting. In the second part of the tool above its bearing part, the diameter of the tool is slightly larger, so that a space is formed between the built-in part and the forming tool. Then, this formed free annular space will be filled with a mixture of granular bulk material and epoxy resin, in the area that extends between the end parts of the built-in part, so that the part that will later represent the filter segment is built. In doing so, the space between adjacent rods in an element composed of rod profiles is filled with a mixture of granular material and hardened duroplastic resin. It is possible to make the ring space with a larger inner diameter, so that the rod-shaped elements are completely covered with granular material on the outside.

After that, the forming tool is heated, so that the resin hardens, and thus the filter part itself. Finally, it is released from the tool and the finished filter tube is taken out.

The filter pipe consists of both closed, watertight end parts and a flow filter segment between them, which is composed of elements in the form of rods and a filter layer made of granular bulk material, whereby the grains of the bulk material are partially connected to each other by means of epoxy resin, whereby the grain size on the one hand and the amount of epoxy resin used on the other hand were adjusted, so that the permeability of the filter layer was determined, i.e. the adjustment was made according to the previously determined required value of water permeability (free porosity) of the filter.

In the last working step - phase, a circular groove is made in the area of the end part on its side, which serves as a connecting part for connecting the other adjacent filter pipe when extending or continuing the pipe. This groove can also be made already in advance on the end part.

In one production variant, the previously formed filter sleeve is transferred over the filter basket made of the above-mentioned rod elements and fixed.

In the case of joining two pipes, a cuff is placed over the end part that guides the connecting pipe, where the inner side of the cuff has a circular recess - a hole, which corresponds to the circular groove on the end part, which passes through the wall to the outside in at least one place of the wall. Through this opening, the cross-section of which corresponds to the total sum of the cross-sections of the corresponding circular groove on the end part of the filter tube and the cuff, a connecting element can be passed through, which can be, for example, a flexible rod made of metal or artificial plastic, a single cable or chain, etc. This connecting element lies partly in the circular groove of the filter tube, partly in the circular groove of the cuff and with its shape locks and connects both parts.

The advantage of this joining technique lies in the fact that it gives a joint that is resistant to stretching and stretching, and that by removing the joining element, both parts can be easily separated again.

The invention will be explained in more detail with the following exemplary embodiments.

They are shown - each in a schematic view - in the pictures.

Figure 1: Semi-finished product for the production of a filter tube according to the invention.

Figure 2: Tool for applying the filter layer to the semi-finished product from Figure 1.

The semi-finished product shown in Figure 1 consists of a first end part 10 made of artificial mass reinforced with glass fibers, a second end part 12 made of the same material and elements in the form of rods 14, which connect the end parts 10, 12. The rod elements 14 are firmly attached to the corresponding connecting nodes 16 on the end parts 10, 12, where they are specially glued for this purpose. The end parts 10, 12 extend along the common longitudinal axis L. The elements 14 extend parallel to this longitudinal axis L.

Elements in the form of rods 14 are composed of the same artificial mass reinforced with glass fibers as the end parts. All of them have a tensile strength of about 200 MPa (determined in accordance with the ISO 527 standard).

Each end part 10, 12 has a circular groove 18 on its free end, which is a connecting part.

Figure 2 shows the tool 20, which generally has a cylindrical shape. The inner cylindrical form is characterized by two different diameters. On one inner deeper part 20u, the tool has a smaller diameter compared to the diameter in the upper part 20o.

The inner diameter of the lower part 20u corresponds to the outer diameter of the end part 10 or 12 shown in Figure 1, so that they can be inserted and laid in the corresponding part 20u.

Figure 2 clearly shows the position of the height of the inner part 20u, which corresponds to the axial length of the end part 10 or 12. In other words: the extension of the cylindrical part 20o covers a certain zone of the semi-finished product shown in Figure 1, which is exclusively occupied by the rod-shaped elements marked with the symbol 14.

Over the upper edge of the tool 20, the semi-finished product protrudes with its other end dclo 12.

A cylindrical movable core 22 is placed in the semi-finished product, which rests on the inner side of the Rod elements 14, i.e. the end parts 10, 12.

The space 24 created between the semi-finished product and the inner part of the wall 20i and the upper space 20o of the tool 20 will be filled with granular bulk material based on quartz sand, whereby the annular space 24 is poured and filled with granular material in the form of a homogeneous mixture with a 6% weight share of epoxy resin, where not only the space between the rod-shaped elements 14 is filled, but the entire annular space 24. This space is filled only in in the area in which the freely extended rod elements 14 are located, which means not the area of the connecting nodes 16.

At the end of the process, the tool 20 is heated, in order to harden the epoxy resin. Then the finalized filter tube, which consists of both end parts 10, 12, rod elements 14 with a filter layer formed, is pulled out of the tool.

The part of the filter tube built with granular material represents the filter part 25, which together with the rod elements 14 builds a unique filter segment 26, which is made with the appropriate coarseness of the granular material and a certain amount of epoxy resin used according to the desired porosity (= water permeability characteristic), so that water can pass through the filter part 25 from the external environment.

Depending on the well installation, one or more filter pipes made in accordance with the invention will be placed vertically, up to the space where the water is located in the lower soil layers. In order to do this, it is necessary to connect adjacent pipes, as already described in the general part, to each other tightly for stretching.

The described filter pipes are allowed to be installed analogously for pumping out and emptying swamps and lakes.

Claims (15)

1. Filter pipe, especially for drainage, with the following characteristics: 1.1. the filter pipe includes at least three parts (10, 26, 12) placed one after the other in the direction of the longitudinal axis (L), namely: 1.1.1 one first end part (10) with one connecting part (18) for direct or indirect connection with other distant filter pipes or well pipes, 1.1.2 at least one filter segment (26) with at least one filter part ( 25 ), which has the possibility of leaking - the flow of water in the radial direction of the filter pipe, 1.1.3 another end part ( 12 ) with one connecting part ( 18 ) for direct or indirect connection with other further filter pipes or well pipes. 2. Filter pipe according to Claim 1, characterized in that at least one end part (10, 12) is watertight. 3. The filter pipe according to Claim 1, characterized in that at least one filter segment (26) has several passing elements in the form of rods (14), placed parallel to the longitudinal axis of the filter pipe, with a tensile strength greater than 50 MPa, between which the water-permeable filter part (25) extends. 4. Filter tube according to Claim 3, characterized in that the filter parts (25) are placed rotationally symmetrically with respect to the longitudinal axis of the filter tube. 5. Filter tube according to Claim 3, characterized in that the filter parts (25) have permeable elements in the form of strips parallel to the longitudinal axis of the filter tube. 6. Filter tube according to Claim 3, characterized in that the rod-shaped elements (14) are attached via a special form to the parts (10, 12) of the filter tube, which are connected to the rod-shaped elements (14) in the longitudinal direction (L) of the filter tube. 7. The filter tube according to Claim 3, characterized in that the rod-shaped elements are connected to the parts (10, 12) of the filter tube, which are connected to the rod-shaped elements (14) in the longitudinal direction of the filter tube. 8. Filter tube according to Claim 1, characterized in that the rod-shaped elements (14) consist of profiles made of epoxy resin reinforced with pultruded glass fibers. 9. A filter pipe according to Claim 1, characterized in that at least one filter part (25) is composed of granular bulk material, where adjacent grains of bulk material are connected to each other and adjusted according to the defined filter characteristic for water permeability. 10. A filter tube according to Claim 8, characterized in that the loose granular means consists of at least one material from the group: quartz, quartz sand, CaCC>3, dolomite, granite, porous glass. 11. A filter tube according to Claim 8, characterized in that the loose granular agent has grains between 1 and 10 mm in size. 12. A filter tube according to Claim 8, characterized by the fact that the grains of the bulk granular agent are glued to each other by means of artificial resin. 13. Filter tube according to Claim 1, characterized in that the filter part (25) has an open - free porosity between 10 and 70 percent of the volume. 14. Filter tube according to Claim 1, characterized in that at least one end part (10, 12) is made of artificial plastic mass reinforced with glass fibers. 15. The filter tube according to Claim 1, characterized by the fact that at least one end part (10, 12) contains as a connecting part a passing circular groove along the circumference.