SK108093A3 - Water extraction components produced by adhesive bonds, process for their manufacture and their use - Google Patents

Abstract

The present invention relates to liquid-permeable components consisting of several segments with no supporting bodies, in which the individual segments are joined by adhesive bonds, especially with a cast elastomer.

Description

Elements for obtaining water produced by means of glued joints, process for their production and their use

Technical field

The invention relates to liquid-permeable elements consisting of immediate segments, wherein the individual segments are connected by glued joints, in particular by means of cast elastomers.

BACKGROUND OF THE INVENTION

The so-called dewatering elements are used for dewatering of flank areas in surface quarries and depots as well as for the production of drinking water. These elements are tubular elements in lengths, which are usually 1 to 3 meters, which are connected to a pipe, for example a lined well. The main purpose of the drainage elements is to filter out the water and thereby protect the well-based pump from abrasive impurities. In order to obtain water of defined quality, such as for the production of drinking water, tubular elements impermeable to water at corresponding depths of the well are used to shield unsuitable groundwater springs. Another prerequisite is the tight connection of the tubular elements to prevent unplanned entry of water. Known joining techniques include threaded screw joints of various sizes and types of threads, plug-in joints, sockets, flanges, bayonet joints, quick-release joints, rubber T-joints, joints formed by friction welding, fusion welding or butt welding.

Drainage plates which contain impermeable, perforated or slotted support bodies with a slight wall thickness such as tubes and are wrapped with textiles or similar materials as filtering means usually exhibit sufficient flexibility to allow the filtering column joined by these techniques to observe deviations from the vertical course borehole during charging.

Unsupported appeal plates, such as those described in DD 109 319, consist of selected granular fractions joined by duroplastically cured plastics and have a greater wall thickness of 25 to 40 mm from a static point of view. The gravel fractions used may range from 1 to 10 mm, preferably from 1 to 6 mm. Likewise, the arrangement of the drainage pipe may be multilayered, i.e. the pipe lining consists of layers of varying grain size, containing a sand of 0.1 to 1 mm grain size as the outer layer. Suitable fillers are known minerals, such as quartz, silicon carbide and other non-hydrolysable minerals in natural form, crushed or in rounded form. The proportion of binder is governed by the choice of filler, but is preferably in the range of 2 to 30% by weight. They therefore constitute particularly rigid elements. The necessary flexibility of the filter column is achieved in these elements by loosely joining the individual elements, which are sealed by rubber or elastomer T-joints.

The net weight of the tubular column presses the face walls of the elements onto the sealing surfaces, thereby securing the seal. The disadvantage of this arrangement is that it is not possible to hang the tubular column in a pendulous manner and, at very tight bending radii, the elements open so far as a result of impacts that the parts of the sealing profile lying thereon can become clamped and thus no longer function.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is an object of the present invention to provide fasteners which do not exhibit the abovementioned disadvantages, which are rationally manufactured and applicable on site. Thus, adhesive systems have been tested which would enable the production of a sealing T-profile in situ by internal and external molds, with a short bonding time, high flexibility with good strength and creep properties, as well as good adhesion to the drainage element.

Accordingly, it is an object of the present invention to provide a liquid permeable element consisting of a plurality of non-supportive segments, which is characterized in that the individual segments are connected by force contact by means of adhesive compounds, in particular by a casting elastomer.

Suitable casting elastomers are unsaturated polyesters of phthalic acid, maleic acid, their hydrides, tetrahydrophthalic acid, adipic acid, and coumaric acid and polyhydric alcohols such as ethylene glycol, propylene glycol, dimers or trimers thereof, neopentyl glycol, pentaerythritol, pentaerythritol as well as their solutions in comonomers such as styrene, alpha-methylstyrene, vinyltoluene, allyl phthalate or trimethylolpropanediallyl ether. Further suitable are epoxy resins as reaction products of epichlorohydrin with bisphenols, novolaks or cresols, aniline, cycloaliphatic or aliphatic dicarboxylic acids as well as monovalent or polyvalent alcohols, as well as hardeners of known types based on polyamines and polyamidoamines.

Casting elastomers are preferably understood to be those casting resins which exhibit a flexible or moderately flexible tensile behavior at tensile strength at a slight tendency to flow and good tensile strength.

Particularly preferred are polyurethane-based casting elastomers consisting of polyisocyanates and polyols or polyamines, with polyols being preferred.

The polyisocyanates are any organic polyisocyanates of known types from polyurethane chemistry. Suitable are, for example, aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates such as those described by W. Siefken in Justus Liebig, Annalen der Chemie, 562, p. 75 to 136, in particular of the formula

Q (NCO) _n> wherein n represents a number of 2 to 4, in particular 2 a

Q represents an aliphatic hydrocarbon radical having 2 to 18 carbon atoms, preferably 6 to 10 carbon atoms, a cycloaliphatic hydrocarbon radical having 4 to 15 hydrocarbon atoms, preferably 5 to 10 carbon atoms, an aromatic hydrocarbon radical having 6 to 15 carbon atoms, preferably 6 to 13 carbon atoms or an araliphatic hydrocarbon radical having 8 to 15 carbon atoms, preferably 8 to 13 carbon atoms.

Particularly preferred isocyanates are 4,4'-diisocyanatodiphenylmethane, polyisocyanate mixtures of the diphenylmethane series, which are obtained in a known manner by the phosphogenation of aniline-formaldehyde condensates, and which contain, in addition to said diisocyanates, varying amounts of higher homologues, 2,4-diisocyanatotoluene by weight, based on the total mixture of 2,6-diisocyanototoluene, hexamethylenediisocyanate, 1-isocyanato-3,3,5-trimeryl-5-isocyanatomethylcyclohexane (isophorone diisocyanate), polyisocyanates based on these unmodified polyisocyanate, or biuret, or any mixture of exemplified polyisocyanates. Preference is given to using polyisocyanates which are liquid at room temperature. Phosphogenation products of aniline and formaldehyde condensates are particularly preferred as organic polyisocyanates.

The polyolyl components have a hydroxyl number of 50 to 800, preferably 95 to 600 mg / KOH / g. It usually consists of a mixture of several polyhydroxyl compounds with a molecular weight range of 62 to 10 000. The following are, for example, suitable as individual components of the mixture:

- low molecular weight polyols known in the chemistry of polyurethanes as chain extenders or crosslinkers, optionally containing ether groups, with a molecular weight range of 62 to 400, such as ethylene glycol, propylene glycol, isomeric butanediols, hexanediols, octanediols, glycerololpropane, trimerylolpropane , polyethylene glycols of said molecular weight range, propylene glycols of said molecular weight range, low molecular weight products of propoxylation of trimethylolpropane of said molecular weight range, or any mixture of such low molecular weight polyols.

Polyether polyols having a molecular weight of more than 400, preferably up to 10 000, in particular in the range of 500 to 6000, such as, for example, alkoxylation products of the abovementioned simple polyhydric alcohols or also alkoxylation products of water, polyamines having at least two NH-bonds or aminoalcohols with at least two active hydrogen atoms or any mixture of such polyether polyols of said molecular weight range. Particularly preferred are the ethoxylation or propoxylation products of the starter molecules exemplified, wherein the ethylene oxide or propylene oxide are used in the mixture or in succession in the alkoxylation reaction.

Polyester polyols of known types from polyurethane chemistry, such as are obtained, for example, by esterification of the abovementioned simple low molecular weight polyols with polybasic acids or polybasic anhydrides. Suitable acid components are, for example, adipic acid, phthalic acid, tetrahydrophthalic acid or hexahydrophthalic acid, or anhydrides of such acids.

Casting elastomers can be influenced in their curing rate by the addition of suitable catalysts. Suitable catalysts are known for the corresponding systems. Examples include tertiary amines. organometallic compounds, for epoxides of a certain acid such as salicylic acid and organic peroxides for curing unsaturated polyesters.

The production of the glued joints is accomplished by laying a molding tool consisting of an outer and an inner mold, which are sealed by means of a hose or a hose of a similar element. The pressing of these hydraulic elements can take place hydraulically, pneumatically or mechanically. The elements or filter tubes are first fixed by a distance fitting that can be contained in the forming tool, regardless of whether the elements or filter tubes are positioned vertically or horizontally. The molding tool is then filled with a casting elastomer.

The cast elastomer mixture is produced in a known manner by batch mixing the reaction resin components or by means of metering and mixing devices consisting of piston or gear pumps, static or dynamic mixers, as well as vacuum degassing devices, both by pressure spraying to promote transport and they may also include agitators and a tempering device.

The curing of these cast elastomers may be at ambient temperature, or at elevated temperature for quicker curing, or a combination of both methods, starting at ambient temperature and after curing at elevated temperature. The molding kits used for this can be made in a heatable design which facilitates processing even at low temperatures.

In principle, the curing time of the cast elastomers is freely selectable, preferably in the range of 30 seconds to 2 minutes.

The glued joint is preferably designed such that the durability of several, preferably at least 6 to 8, pieces of filter tubes or connected elements (segments) for transport or installation is guaranteed;

the flexibility of the assembled filter columns is guaranteed up to a certain degree. For this purpose, a zone of flexibility is formed between the connected filter tubes by means of cast resin.

the flexibility zone ensures that the filter column can observe deviations from the vertical direction of the drain well during installation or installation;

endless production of filter pipe branches is possible which is characterized by absolute tightness on the filter joints and is avoided by the clogging of the well with sand;

it is possible to use filter columns in each installation position (horizontal / vertical). This opens up the possibility of further retrofitting as drainage pipes, eventually removing and removing media from the depots and the like.

According to the present invention, the elements or filter tubes thus produced can be used, for example, as drainage elements in mining, preferably in opencast mining, in landfill sites, as well as in agriculture, construction and forestry. Naturally, casting elastomers must be used for the production of drinking water from which, due to their chemical composition, they do not split off or leach no harmful substances.

For special applications, it may be expedient or necessary for a limited number of individual segments to be bonded to each other, which themselves are loosely connected by means of elastic T-couplings. It is also possible to bond these T-couplings with a casting elastomer.

Furthermore, it is also possible within the scope of the present invention to use partially impermeable segments instead of liquid-permeable segments (for example to seal against certain groundwater).

DETAILED DESCRIPTION OF THE INVENTION

The subject matter of the present invention is explained in more detail below by means of examples.

Initial component a)

The starting component (a) is a polyether blend consisting of:

parts by weight, consisting of 1 mole of propylene glycol, 87 parts by weight of propylene oxide and 13 parts by weight of ethylene oxide, having a hydroxyl number of 28, parts by weight consisting of 1 mole of trimethylolpropane, 87 parts by weight of propylene oxide and 13 parts by weight of ethylene oxide, parts consisting of 1 mol of trimethylolpropane, 82.5 parts by weight of propylene oxide and 17.5 parts by weight of ethylene oxide, having a hydroxyl number of 35,

7.7 parts by weight of ethylene glycol having a hydroxyl number of 1806 and parts by weight of a powdered zeolite having a hydroxyl number of 165, a viscosity at 25 ° C of 1000 mPa.s and a density at 20 ° C of 1.03.

Starting component b)

The starting component b) is a mixture of isomers of diphenylmethane diisocyanate having a predominant proportion of 4,4-isomers as well as a proportion of higher-functional polymers as well as tripropylene glycol-based prepolymers. Isocyanate content is 28.5%, viscosity at 25 ° C 140 mPa.s.

Initial component c)

The starting component c) is diazabicyclooctane (accelerator).

Said starting components may be processed as follows:

100 parts by weight of the polyol corresponding to the starting component a) are mixed with 38 parts by weight of the isocyanate corresponding to the starting component b) as well as 0.3 parts by weight of the accelerator corresponding to the starting component c) at 25 ° C in a two-component low-pressure device. dynamic mixer. The gelling time is 40 s. After 3 minutes, the test specimen can be removed from the mold. The hardness after complete curing is determined using 65 Shore A.

Determination of joint strength:

Concrete bending prisms according to DIN 1048, with dimensions of 4 x 4 x 16 cm, were prepared according to the procedure of DD 109 317. A mixture of silicone oil and siloxane was used as a separating agent. For binder fractions of 2 to 8 mm and 2 to 4 mm, the proportion of binder is always 5% by weight. In a four-point test, a 5816 N fracture force was found on test specimens having a grain size of 2 to 8 mm. The test specimens were always squeezed to a length of 8 cm and bonded by free, non-pressure casting on faces equipped with a separating agent. The elastomer is applied with a polyurethane mixture according to Example 1 in a layer with a thickness of 10 mm. The casting is carried out so as to form a T-shaped profile which overlaps the sides of the test body by 10 mm in each case. After curing at about 22 ° C for 24 hours, four-point bending strength was tested.

Granularity 2 to 8 mm 5807 N Granularity 2 to 4 mm 6150 N.

The fracture is carried out for both types of test specimens both in the test material of the drainage segment and partly on the boundary surfaces with the connecting segment. The test arrangement is 100 mm apart and the pressure spacing is 45 mm. The fastener was located centrally between the pressure blade. The T-shaped overlap was located in the tensile zone.

Example 1

Drainage elements, corresponding to DD 109 317, having a gravel fraction with a grain size of 2 to 4 mm and a binder fraction of 5% by weight, with an inner diameter of 414 mm with a wall thickness of 32 mm, are stacked one above the other. the side of the pipe is fixed so that a gap of 10 mm is produced.

This gap is cast by loose, non-pressure casting as described above. After ten minutes of extension, the mold halves are removed. The joint of the drainage elements has the desired properties.

Example 2

The segments of the 25 cm drainage elements described in Example 1 are coupled to each other by the procedure of Example 1. However, the arrangement of the tube segments for casting is realized horizontally. The mold apparatus of Example 1 is completed with a cover plate to form a closed mold. The filling of the interior of the mold is effected by a bore at the upper apex point of the annular mold by means of a dosing and mixing apparatus for 80 seconds by free casting. After 10 minutes of residence in the mold, both halves of the mold can be removed.

Example 3

The experiment set-up was chosen similar to Example 2; however, the casting is carried out from the lower apex of the mold ring through a replaceable hose for 2 minutes. The mold is removed again after 10 minutes.

Example 4

The paired segments of Example 2 are subjected to a creep stress test. The vertical load is 5 t. After 1000 hours, the relative compression in the elastic fastener is less than 0.1%.

Example 5

The paired segments of Example 2 are subjected to a tensile test so that the adhesive bond is damaged. The maximum tensile load at break was 12 KN.

Example 6

According to the above-mentioned method, a drilled well with unsupported drainage segments was built.

In FIG. 1 shows a well borehole with retaining well tubes 2 produced according to the present invention, a lost plate bottom 5, a UWM pump 3 (underwater motor) with an ascending line 4 and a gravel ring space.

Pipe filters 2 according to example 1 with low tensile strength, which are installed vertically, are suitable. Following the procedure of Example 2, six individual segments of 1 m in length are connected to each other on their front faces. After the adhesive has cured, the assembly rods 6 are guided through this tubular section 6 and screwed onto the plate bottom.

5 so that the tubular section 6 standing on the plate bottom can be used

6, fit into the prepared drill hole. The clamping of the pipe column takes place above the pipe section on the mounting rod.

Further construction can now be carried out as follows:

The following and all other tubular sections 6 are joined and bonded as described above, using a mounting plate instead of the bottom plate 5. The tubular section 6 is placed over the borehole and retained on the lowest filter tube. The mounting rod is released and screwed onto the rod already in the drilled hole. The two tubular sections are joined prior to placement as described in Example 1. The tubular branch is lowered into the borehole, retained on the mounting bar above the last filter tube, and the process is repeated until the final stage is reached.

During the assembly process, the tubular sections 6 form stable assembly units which allow a rational working procedure. The deflection of the filter tube from the vertical plane is considerably limited, but the mobility of the filter column remains so that the tube can be adapted to borehole irregularities and additional rock shifts. Compressed compressive forces and associated additional stresses shall be avoided.

Claims (9)

PATENT CLAIMS 1. A liquid-permeable element comprising a plurality of non-supportive segments, characterized in that the individual segments are connected by glued joints, in particular by means of a casting elastomer. Element according to claim 1, characterized in that the individual segments have a particularly circular cross-section and consist of a mineral filter material, joined by a cast resin based on epoxides, unsaturated polyesters or polyurethanes. Element according to either of Claims 1 and 2, characterized in that polyurethanes are used as casting elastomers or casting resins. Element according to one of Claims 1 to 3, characterized in that a plurality of glued elements are connected by elastic T-couplings. Element according to one of Claims 1 to 4, characterized in that the individual segments consist of a polyurethane casting resin. 4, characterized by a gravel mixture Element according to one of claims 1 to 5, characterized in that elements for adjusting the gap spacing are provided between the individual segments. Element according to one of Claims 1 to 6, characterized in that it comprises partially impermeable segments instead of liquid-permeable segments. W \ J - 14 Use of elements according to any one of claims 1 to 7 in drainage and in the construction of wells. Use of elements according to any one of claims 1 to 7 in dewatering in mining.