AU666843B2 - 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

OPI DATE 17/11/92 APPLN. ID 14389/92 f~ Il~IIII~l~I~~~I A0 1 3P DATE PCT NUMBER PCT/EP92/00707 AU92 14389 (51) Internationale Patcntlassifikation 5 (11) Internationale Veriiffentlichungsnummner: WO 92/18702 E02D 3/10, E02B 11/00 Al (43) Internationales Veriiffentlichungsdatuim: 29. Oktober 1992 (29.10.92) (21) Internationales Aktenzeichen: PCT/EP92/00707 (74) Gemeinsanier Vertreter: BAYER AKTJENGESELL- SCHAFT; D-5090 Leverkusen (DE).

(22) Internationales Anmeldedatum: 3.Mfirz 1992 (31.03.92) (81) Bestiminungsstaaten:- AT (europtiisches Patent), AU, BE Priorititsdaten: (europiiisches Patent), CA, CH- (europiiisches Patent), G 91 04 265.8 U 9. April 1991 (09.04.9 1) DE CS, DE (europiiisches Patent), DK (europtiisches Pa- P 4131 099.3 16. September 1991 (16,09.9 1) DE tent), ES (europiiisches Patent), FR (europilisches Patent), GB (europiiisches Patent), GR (eurooliisches Patent), IT (europiiisches Patent), JP, KR, LU (europfii- (71) Anmelder (far alle Bestirnunungsswaaten ausser US): BAYER sches Patent), MG (europisches Patent), NL (europili- AKTIENGESELLSCHAFT [DE/DE]; D-5090 Leverku- sches Patent), PL, RU, SE (europiiisches Patent), US.

sen LAUSITZER BRAUNKOHLE AKTIENGE- SELLSCHAFT (LAUBAG) [DE/DE]; Knappenstrasse 1, D-7840 Senftenberg Ver~ffentlicht Mil inlernationalem Recherchenberich.

(72) Erfinder; und Erfinder/Anmelder (nur ffr US): FRANKE, Joachim [DE/ DE]; Gruenen Baeumchen 19, D-5060 Bergish Gladbach GRDNE, Horst [DE/DE]; Neuenkamp 11, D- 5653 Leichlingen FAHLING, Friedhetin [DE/ 68 4 DE]; Burgstrasse 9, D-4130 Moers 1 TOST, Reinhard [DE/DE]; Heinrich-Rau-Strasse 28, D-7500 Cottbus FAHLE. Werner IDE/DE]; Am Priorgraben 54, D-7500 Cottbus DOMKE, Konrad [DE/DE]; Albert-Schweitzer-Strasse IS, D-7840 Senftenberg (DE).

(54) Title: WATER EXTRACTION COMPONENTS PRODUCED BY ADHESIVE BONDS, PROCESS FOR THEIR MA- NUFACTURE AND THEIR USE (54) Bezeiclinung: DURCI- KLEBEVERBINDUNGEN I-ERGESTELLTE WASSERGEWINNUNGSELEMENTE, VER- FAH-REN ZU DEREN HERSTELLUNG UND DEREN VERWENDUNG (57) Abstract The present invention relatc, 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.

(57) Zusainmenfassung Die vorliegende Erfindung betrifft flissigkeitsdurchlilssige Elemente, die aus mehreren stiltzkbrperfreien Segmenten bestehen, wobei die einzelnen Segmente durch Klebeverbindungen, insbesondere mit einem Giesselastomer, verbunden sind.

var) ci i A *7 n f, L/JP~l Zfm L I i-U U7 tU WATER EXTRACTION COMPONENTS PRODUCED BY ADHESIVE BONDS, PROCESS FOR THEIR MANUFACTURE AND THEIR USE This invention relates to liquid-permeable elements which consist of several support-free segments, the individual segments being connected by bonded joints, more particularly using a casting elastomer.

So-called drainage elements are used for draining excavation sites in open cast mining and waste disposal sites and for procuring drinking water. These elements are tube segments, normally in lengths of 1 to 3 M, which are joined to form a tube which is used, for example, to line a drilled well. The basic function of the drainage element is to f ilter out water and hence to protect the pump situated at the bottom of the well against abrasive contaminations. In the procurement of waters of defined quality, for example drinking water, water- impermeable tube segments are used to seal of f unsuitable ground water channels at the corre- ,sponding drilling depths. The tube segments also have to be firmly joined to prevent any unplanned entry of water.

Known techniques include screwthreaded joints of different dimensions and thread types, push-fit joints, socket joints, flanges, bayonet couplings, quick-coupling joints, rubber T sockets, joints friction welding, fusion or butt welding.

Drainage elements which comprise an impermeable, perforated or slotted thin-walled support as the tube and which are wrapped in textile or textile-like materials as the filter material normally have sufficient flexibility to enable the filter colun joined by these techniques to follow any deviations of a drainage bore from the vertical during installation.

Support-free drainage'elements of the type described, for example, in DD 109 317 consist of selected particle fractions bonded with thermosets and, for static reasons, have considerable wall thicknesses of 25 to 40 mm. The gravel fractions used may be in the range from 1 to 10 mm and are preferably -in the range from 1 to 6 m-n. The drainage tube may also have a multilayer construction, i.e.

the tube wall consists of layers of different particle sizes incorporating the 0.1 to 1 mm sand layer as outer skin. Suitable fillers are known minerals, such as quartz, silicon carbides, and other minerals which cannot be hydrolytically influenced in natural, broken or edgerounded form. The binder component is determined by the particular fillers used, but is preferably between 2 and by weight. Accordingly, the elements in question are extremely rigid. With these elements, the necessary flexibility of the filter column is achieved by loose joining of the individual elements which are sealed by a T profile socket of rubber or elastomers.

The natural weight of the tube column presses the end of the elements onto the sealing surfaces and hence provides for sealing. The disadvantage of this arrangement is o. that hanging installation ,of the tube column is not possible and, with very small radii of curvature, the joints between the elements open out to such an extent that parts of the external sealing profile can become wedged so that they are unable to perform their function.

Now, the problem addressed by the present invention 25 was to provide joining elements which would not have any of these disadvantages, which could be efficiently produced and which -could be used on site. More specifically, the problem addressed by the present invention was to provide adhesive systems which would enable the T sealing profile to be made in sicu using an inner mold and an outer mold and which would have short curing times, high flexibility coupled with high strength and good creep behavior and high strength of adhesion to the drainaqe element.

-3- Accordingly there is provided, by the present invention, an element, for use in drainage and in water disposal or for use in lining wells or the procurement of drinking water, said element consisting of a series of individual segments that are tubular in shape, and (ii) liquid permeable or partially impermeable, the said element being further characterised in that the individual segments are joined by bonded joints, said joints being flexible and comprised of one or more curable casting elastomers.

The invention will now be described with reference to preferred performance features, specific illustrative examples, and an accompanying illustrative drawing. It will be understood that, being preferred and illustrative, the following description should not be limitatively construed.

Suitable -asting elastomers are those based on unsaturated polyesters ofphthalic acid, maleic acid, their anhydrides, tetrahydrophthalic acid, adipic acid, cumene acid and polyhydric alcohols, such as ethylene glycol, propylene glycol, their dimers and/or trimers, neopentyl glycol, pentaerythritol and solutions thereof in comonomers, such as styrene, a-methyl styrene, vinyl toluene, allyl phthalate or trimethylol propane diallyl ether; also epoxy resins as reaction products of epichlorohydrin with bisphenols, novolaks and/or cresols, aniline, cycloaliphatic or aliphatic dicarboxylic acids and monohydric or polyhydric alcohols and curing agents known per se based on 20 polyamines, polyamidoamines, mercaptans and acid anhydrides.

Preferred casting elastomers are casting resins which combine a minimal tendency to creep and high tensile strength with flexible or medium-flexible tensile behaviour.

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

25 The polyisocyanates are organic polyisocyanates knownper se from polyurethane chemistry. Suitable polyisocyanates are aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates of the type described, for example, by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136, more particularly those corresponding to the following formula Q(NCO)n in which n 2 to 4 (preferably 2) and o-A Q is an aliphatic hydrocarbon radical containing 2 to 18 1220pNYpdocs\grs,48334O\jgs,3 (preferably 6 to 10) carbon atoms, a cycloaliphatic hydrocarbon radical containing 4 to 15 (preferably to 10) carbon atoms, an'aromatic hydrocarbon radical containing 6 to 15 (preferably 6 to 13) carbon atoms or an araliphatic hydrocarbon radical containing 8 to (preferably 8 to 13) carbon atoms.

Particularly preferred isocyanates are 4,4'-diisocyanatodiphenyl diphenyl methane, polyisocyanate mixtures of the diphenyl methane series which are obtained in known manner by phosgenation of aniline/formaldehyde condensates and which, in addition to the diisocyanates mentioned, contain varying amounts of higher homologs, 2,4-diisocyanatotoluene and technical mixtures thereof with up to 35% by weight, based on the mixture as a whole, of 2,6-diisocyanatotoluene, hexamethylene diisocyanate, 1-isocyanato- 3,3,5-trimethyl-5-isocyanatomethyl cyclohexane (isophorone diisocyanate), urethane-, carbodiimide-, isocyanurate-, allophanate- or biuret-modified polyisocyanates based on the unmodified polyisocyanates mentioned or mixtures of the polyisocyanates mentioned by way of example. The corresponding polyisocyanates liquid at room temperature are preferably used. Particularly preferred organic polyisocyanates are the phosgenation products of aniline/formaldehyde condensates.

The polyol component has a hydroxyl value of 50 to 800 and preferably 95 to 600 mg KOH/g. In general, it consists of a mixture of several polyhydroxyl compounds having a molecular weight in the range from 62 to 10,000. The mixture may consist, for example, of the following individual constituents: S Low molecular weight polyols optionally containing ether groups and having a molecular weight of 62 to 400 known as chain-extending or crosslinking agents in polyurethane chemistry, such as ethylene glycol, propylene glycol, the isomeric butanediols, hexanediols, octanediols, trimethylol propane, glycerol, pentaerythritol and/or sorbitol, polyethylene glycols having a molecular weight in the range mentioned above, propylene glycols having a molecular weight in the range mentioned above, low molecular weight propoxylation products of trimethylol propane having a molecular weight in the range mentioned above or mixtures of these low molecular weight polyols.

Polyether polyols having a molecular weight above 400, preferably up to 10,000 and, more preferably, in the range from 500 to 6000, for example the alkoxylation products of the simple polyhydric alcohols mentioned or even the alkoxylation products of water, polyamines containing at least two NH bonds and/or aminoalcohols containing at least two active hydrogen atoms or mixtures of such polyether polyols having a molecular weight in the range mentioned. Particular preference is attributed to the ethoxylation and/or propoxylation products of the starter molecules mentioned by way of example or of mixtures of the starter molecules mentioned by way of example, ethylene oxide and/or propylene oxide optionally being used in admixture and/or successively in the alkoxylation reaction.

Polyester polyols known per se from polyurethane chemistry, for example of the type obtained by esterification of the simple low molecular weight polyols mentioned above with polybasic acids or anhydrides of polybasic acids. Suitable acid components are, for example, adipic acid, phthalic acid, tetrahydrophthalic acid and/or hexahydrophthalic acid and their anhydrides.

's 7 z, j^ Casting elastomers may be influenced in their curing rate by addition of suitable catalysts. Suitable catalysts for the particular systems are known per se and include, for example, tertiary amines, organometallic compounds; in the case of epoxides, certain acids (for example salicylic acid) and organic peroxides for the curing of unsaturated polyesters.

The bonded joint is produced by application of a mold consisting of an outer section and an inner section which are sealed by hoses or hose-like elements. These sealing, elements may be applied hydraulically, pneumatically or mechanically. The elements or filter tubes are fixed beforehand by spacer pieces, which may be present in the mold, irrespective of whether the elements or filter tubes are fitted together vertically or horizontally. The mold is then filled with the casting elastomer.

The casting elastomer mixture is prepared in known manner by mixing the casting resin components in batches in two-component metering and mixing units which consist of piston or gear pumps, static and/or dynamic mixers and vacuum generators for degassing and which may contain means for applying pressure to promote transport and also stirrers and temperature-control systems.

The casting elastomers may be cured at ambient temperature or, to accelerate curing, at elevated temperature or by a combination of both methods, i.e. by pre-curing at ambient temperature and full curing at elevated temperature after demolding. To this end, the mold fittings used may be of a heatable design to facilitate processing, even at relatively low temperatures.

Basically, the cure time of the casting elastomers may be freely selected, but is preferably in the range from seconds to 2 minutes.

The bonded joint is preferably established in such a way that the stability of several, preferably at least 6 to 8, filter tube or element joints (segments) is guaranteed both for transport and for installation; the flexibility of the joined filter columns is guaranteed to a certain extent. To this end, a flexibility zone iz formed by the casting resin between the filter t~mes to be joined; the flexibility zone ensures that the filter column is able to follow any deviations of a drainage bore from the vertical during assembly and during installation; columns of filter tubes can be continuously produced with perfect seals at the filter joints so that there is no danger of the well silting up; the filter columns can be installed in any position (horizontal/vertical). Accordingly, the filter columns can also be used as drainage tubes and for raising and diverting media from waste disposal sites and the like.

According to the invention, the elements or filter tubes thus produced are used, for example, as drainage elements in mining, preferably in open-cast mining, in waste management and in agriculture, building construction and forestry. In the procurement of drinking water, the casting elastomers used must of course be of such a chemical composition that no physiologically harmful substances can be el'iminated or dissolved out.

For special applications, it may be useful or necessary to bond a limited number of individual segments to one another and then loosely to apply an elastic T socket. It is also possible in this case to bond the T socket with the casting elastomer.

It is also possible in accordance with the invention to use partly impermeable segments instead of liquidpermeable segments (for example for sealing against certain ground water channels).

The invention is illustrated by the following Examples.

Examples Starting component a) is a polyether mixture consisting of: S 35 parts by weight consisting of 1 mol propylene glycol, 87 parts by weight propylene oxide, 13 parts by weight ethylene oxide; OH value 28 30 parts by weight consisting of 1 mol trimethylol propane, 87 parts by weight propylene oxide, 13 parts by weight ethylene oxide; OH value 25 parts by weight consisting of 1 mol trimethylol propane, 82.5 parts by weight propylene oxide, 17.5 parts by weight ethylene oxide; OH value 7.7 parts by weight ethylene glycol; OH value 1806 5 parts by weight zeolite powder; OH value 165, viscosity at 25"C 1000 mPa.s, density at 1.03.

Starting component b) is a diphenyl methane diisocyanate isomer mixture predominantly containing 4,4-isomers and, in smaller amounts, polymers of higher functionality and prepolyers based on tripropylene glycol. It has an isocyanate content of 28.5% and a viscosity at 25'C of 140 mPa.s.

Starting component diazabicyclooctane (accelerator).

These starting components may be processed as follows: 100 Parts by weight polyol corresponding to starting component 38 parts by weight isocyanate corresponding to starting component b) and 0.3 part by weight accelerator corresponding to starting component c) are mixed by means of a dynamic mixer at 25*C in a low-pressure two-component machine. The gel time is 40 s. After 3 minutes, the test specimen can be demolded. Hardness after complete curing: Shore A.

Determination of bond strength: Concrete bending prisms (measuring 4 x 4 x 16 cm, DIN 1048) were made in accordance with DD 109 317. Silicone oil/siloxane mixtures were used as the release agent. The binder component was 5% by weight for the 2 to 8 mm grain fraction and 5% by weight for the 2 to 4 mm grain fraction.

In the four-point bending test, a breaking force of 5816 N was determined for the 2 to 8 mm grain test specimens. The test specimens were each halved to a length of 8 cm and joined by free pressureless casting at their ends coated with release agent in accordance with Example 1. A polyurethane mixture corresponding to Example 1 was applied in a layer thickness of 10 mm as the casting elastomer.

Casting was carried out in such a way that a T-shaped profile was formed, overlapping the sides of the test specimen by 10 mm. Four-point bending strength was tested after curing for 24 h at approx. 22"C.

Grain fraction 2 8 mm: 5807 N Grain fraction 2 4 mm: 6150 N ;I i- In bnth types of test specimen, fracture occurred both in the test material of the drainage segment and also partly at the interface with the connecting element. The test arrangement consisted of supports arranged at a distance of 100 mm and pressure cutters arranged at a distance of 45 mm. The connecting element was positioned centrally between the pressure cutters. The T-shaped overlap was situated in the tensile zone.

Example 1 Drainage elements according to DD 109 317 consisting of a 2 to 4 mm gravel fraction and a binder component of by weight with an external diameter of 414 mm and a wall thickness of 32 mm are arranged one above the other and fixed by means of a supporting ring mold consisting of 1 mold half for the inside and another mold half for the outside of the tube in such a way that a gap of 10 mm is formed.

This gap is filled by free pressureless casting as described above. After standing for 10 minutes, the mold halves are removed. The drainage element joint showed the desired properties.

Example 2 25 cm long segments of the drainage elements described in Example 1 were joined to one another in pairs in accordance with Example 1. On this occasion, however, the tube segments were arranged horizontally for casting. The mold assembly of Example 1 was completed by a cover plate,so that a closed mold was formed. The mold cavity was filled through a bore in the upper peak of the mold ring by free casting for 1.25 minutes using a two-component metering and mixing machine. After standing for 10 minutes, the two mold halves could be removed.

Exampole 3 The test arrangement was the same as in Example 2, except that the mold cavity was filled in 2 minutes from the lower peak of the mold ring through a replaceable hose.

The two mold halves could again be removed after 10 mins.

Exampl.e 4 Segments from Example 2 joined together in pairs were subjected to long-term testing under pressure. A vertical load of 5 t was applied. The compression in the elastic connecting element was less than 0.1% after 1000 hours.

Example Segments from Example 2 joined together in pairs were tensile-tested by applying load to the bonded joint. The maximum tensile stress to failure was 12 1KN.

Example 6 A drilled well was lined with support-free drainage segments by the methods described above.

Figure 1 shows a drilled well lined with support-free well tubes 2 produced in accordance with the invention, lost base plates 5, a UW14 (underwater motor) pump 3 with a riser 4 and a gravel-filled annular space.

Vertically installed low-tensile gravel filteZ" according to Example 1 are used as the well tubes 2. Six individual segment,-- I 'meter in length are joined to one another at their eid faces 1 by the method according to Example 2. After curing of the adhesive, the run-in pipe is guided through the tube section 6 arnd screwed to the base plate 5 so that tube section 6 can be lowered vertically into the prepared bore hole on the base plate 5. The tube column is held by the run-in pipe above the tube section by means of supports.

The further lining of the well may then be carried out Z)x .*l as follows: The next tube section 6 and all furt r tube sections 6 are fitted together and bonded as already described, a run-in plate being used instead of the base plate 5. The tube section 6 is positioned over the well and held by the lowermost filter tube. The run-in pipe is released and screwed to the pipe already present in the well. The two tube sections are joined in situ as in Example 1. The tube column is lowered into the bore hole and held by the pipe above the last filter tube, this operation being repeated until the final stage is reached.

During running in, the tube sections 6 form stable running-in units which provide for efficient operation.

Displacement of the filter tubes from the perpendicular is substantially minimized although the filter column remains movable so that the tube column is able to follow any irregularities in the bore and any subsequent shifting of the rock.

Squeezing forces and hence additional stressing are avoided.

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Claims (2)

1. 4.. 4 e 4 4 4 4 4 44 o o THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. An element, for use in drainage and in water disposal or for use in lining wells or the procurement of drinking water, said element consisting of a series of individual segments that are tubular in shape, and (ii) liquid permeable or partially impermeable, the said element being further characterised in that the individual segments are joined by bonded joints, said joints being flexible and comprised of one or more curable casting elastomers. 2. An element as claimed in claim 1, characterized in that the individual segments are circular in cross-section and consist of a mineral filter material bonded with epoxy, unsaturated polyester or polyurethane casting elastomer. 3. An element as claimed in claim 1, characterized in that the individual segments consist of a mixture of gravel and polyurethane casting elastomer. 4. An element as claimed in any one of the preceding claims, in which the polyurethane casting elastomer consists of polyisocyanate and polyamine or polyol. An element as claimed in claim 4, in which the polyisocyanate corresponds to the formula Q(NCO), in which n= 2 to4 and Q is an aliphatic hydrocarbon radical containing 2 to 18 carbon atoms, a cycloaliphatic hydrocarbon radical containing 4 to 15 carbon atoms, an aromatic hydrocarbon radical containing 6 to 15 carbon atoms or an araliphatic hydrocarbon radical containing 8 to 15 carbon atoms. 9S 1208pApdocs\grs,483340\jgs, 13
2. 14- 6. An element as claimed in any one of the preceding claims, in which the polyol consists of a mixture of several polyhydroxyl compounds having a molecular weight in the range from 62 to 10,000. 7. An element as claimed in any one of the preceding claims, wherein an elastic T socket is applied to joined individual segments. 8. An element as claimed in claim 1, substantially as herein described with reference to any one of the foregoing examples thereof. 9. An element as claimed in claim 1, substantially as herein described with reference to the accompanying drawing. 4* DATED this 20th day of December, 1995. *o BAYER AKTIENGESELLSCHAFT and 20 LAUSITZER BRAUNKOHLE AKTIENGESELLSCHAFT (LAUBAG) By Its Patent Attorneys SDAVIES COLLISON CAVE 4 95122Op:\%vpdocs\grs,48334\jgg, 14