EP0358857B1 - Drain manhole - Google Patents

Abstract

The invention relates to a drain manhole comprising a preferably corrugated pipe (1), in the wall of which openings are formed for connection to piping (36) and at the lower part of which a weight is disposed for increasing the stability. According to the invention, the weight takes the form of a ballast arrangement which is separated from the pipe (1) and can be attached to the latter. The said ballast arrangement may take the form of a chamber (3) which can be filled with liquid or bulkable solid ballast material and is formed on or can be attached to the underside of the pipe. The ballast material is preferably a bulk material and/or a liquid. Consequently, the time-consuming filling with concrete, which was necessary hitherto in the production of drain manholes, is eliminated and the transportation of the pipes is easier as they do not contain, as hitherto, a concrete weight from the very outset. <IMAGE>

Description

The invention relates to a drainage shaft according to the preamble of claim 1, as is known from US-A-2 180 268.

Such a drainage shaft has an upright pipe to be let into the ground, into which at least one essentially horizontal pipe opens.

The main purpose of such a drainage shaft is to make the drainage pipes flowing into it accessible for inspection and cleaning equipment, and it must be so designed and dimensioned that, among other things, it can be cleaned so that water samples can be taken to check unauthorized discharges and that, if necessary, ventilation of the pipelines is also possible.

The pipe forming the actual shaft can be made of any suitable material, provided it is sufficiently weather-resistant and can withstand the pressure of the soil into which the shaft is to be inserted. Such a tube is preferably made of plastic, and is more preferably designed as a corrugated tube, since the required strength of the tube can be produced in this way with the least possible material expenditure. The corrugations of the tube can be one or more juxtaposed, helically arranged beads are formed, but are preferably formed as circumferential beads.

In order to avoid deposits, the pipelines can open directly into the area of the closed bottom of the pipe, this bottom in turn also having channel-like depressions which connect the individual pipeline openings to one another, in order to ensure in this way that sludge conveyed in is not deposited in the drainage shaft , but is promoted.

However, it is also possible to provide the pipeline openings at a considerable distance above the bottom of the drainage shaft in the pipe forming the same; suspended matter carried by the water can thus settle between the floor and the pipe mouth. In this case, the drainage shaft acts as a sand trap.

When connecting the known pipe is placed in a suitable pit, the mouths of the pipes are made and then the pit is filled so that the pipe is only accessible through its top cover.

So that the pipe does not fall over during this work, but has sufficient stability, the lower part of the pipe has been poured with concrete.

Since there is usually not enough time at the construction site due to the required setting time of the concrete to pour the pipes there with concrete, it was necessary to carry out this operation in the manufacturing plant, which is normally a production facility for plastic objects that are naturally easy to handle of fresh concrete is not set up. The production of the well-known drainage shafts was therefore cumbersome.

A further problem was that the pipes had to be sealed on their underside until the concrete set, in order to prevent the still liquid concrete from leaking. This sealing work is complex.

Pouring the pipes with concrete further extends their manufacturing time considerably, and the pipes must stand up during the setting time of the concrete, so that they cannot be stacked, for example, to save space. A relatively large production area is therefore required for the production of the known drainage ducts.

The handling and especially the transport of the finished drainage ducts is cumbersome and difficult due to the heavy concrete weight; in particular, stacked pipes can crush and damage each other.

Based on this problem, an object of the invention is to at least partially eliminate the above-mentioned problems and to further develop the known drainage shaft in such a way that manufacture and transport are quicker and easier than hitherto possible and the installation on the construction site can nevertheless be carried out without problems.

This object is solved by the features of claim 1.

Here, according to the invention, instead of the concrete cast into the pipe by the pipe manufacturer, a separate ballast arrangement is provided, which can only be assembled with the pipe at the installation site.

According to the invention, the ballast arrangement has a chamber arranged or attachable on the underside of the tube, which is filled with ballast material can. Any bulk material present at the construction site can serve as ballast material, such as, for example: gravel, sand, earth from the excavation and the like. However, it is also possible to use a liquid as ballast material, in particular water or concrete that has not yet set. In this way, it is not necessary to transport prefabricated ballast bodies to the construction site, but any material that is currently available can be used on the construction site as ballast material.

It is fundamentally possible to form or close the pipe on its underside, the lower end of the pipe being at a distance from the pipe openings. A chamber for receiving the ballast material from the closed lower part of the tube is thus formed.

At the construction site, before or after lowering the pipe into the construction pit, the pipe can be filled with the ballast material up to a prescribed filling level, for example up to the pipe mouths, so that the position of the pipe is reliably ensured.

According to a preferred embodiment of the invention, however, it is particularly advantageous that the chamber for receiving the ballast material is formed by a closable container separate from the tube. Here it is possible to separate the container from the pipe at a particularly favorable location on a construction site, e.g. under a sand silo to fill; the transport of this filled container is extremely easy because of its small dimensions compared to the tube forming the drainage shaft.

The container is preferably designed to be watertight, it being possible for bulk material and liquid together as ballast material to use. For example, a trough-like container can first be filled with gravel and then covered with a layer of viscous quick-setting cement that sets in a short time and forms the closure of the container to a certain extent.

It is possible to design the container as a hollow ring body, the cavity of which is filled with ballast material and which anchors the lower part of the tube. The particular advantage of such an arrangement is the stability of the drainage shaft according to the invention, which is considerably improved because of the large footprint, without having to accept an increased weight.

However, the container is preferably designed as a canister, i.e. as a closable container that is easy to transport even when filled. This canister is in turn designed so that it fits from below into the interior of the tube forming the drainage shaft and preferably also seals against this tube. During assembly, it is possible to either insert the filled or empty canister into the pipe before installing the drainage shaft or to set it up in the construction pit and to lower the pipe above the canister during assembly. If the canister is still empty after assembly and, if necessary, also after installation of the drainage shaft, it is possible to gain access to the opening of the canister from the inside of the pipe and thus to fill the canister.

The lid of the canister preferably has a much smaller diameter than the canister itself and can be snapped into the associated opening in the upper wall of the canister, so that the canister can be easily filled and prevented after installation of the drainage shaft according to the invention, for example by means of a water hose that water splashes out of the opening during the filling process. The lid can then be attached by means of a suitable rod, at the end of which the lid can be attached.

The outer wall of the canister and the inner wall of the tube can be shaped to be complementary to one another, so that the canister fits exactly into the lower end of the tube, at most while leaving a necessary tolerance clearance free. Here, the mutually facing surfaces of the canister and tube can be slightly conical, so that the canister assumes a sealing seat in the tube. Preferably, however, the outer wall of the canister is slightly conical, while the tube is cylindrical and can therefore be designed as a section of an endless tube produced by extrusion. If a suitable angle is set between the pipe and canister wall, which is preferably in the range of 0.5 °, the canister can be inserted into the pipe from below like a sealing plug despite the occurrence of considerable tolerances. Here, the tube is preferably formed with circumferential beads, which can optionally accommodate a lubricating and sealing compound, which facilitates the insertion of the canister into the tube and at the same time ensures an even better and more permanent seal. Otherwise, it is harmless if the canister slightly expands the pipe, because the pressure of the soil surrounding the pipe supports the pipe from the outside, thus reducing the stresses in its wall and therefore preventing creeping in the pipe material.

In order to ensure the described clamping action, according to a preferred embodiment of the invention, the canister is provided with a bottom whose outside diameter does not exceed that of the canister side wall. The bottom of the canister is thus flush with the underside of the pipe, but can also protrude a little from the pipe end or sit in the pipe if unfavorable tolerances occur if the required sealing seat is to be achieved. The canisters themselves have the advantage that they can be stowed close together for transport.

According to an alternative embodiment of the invention, however, it is also advantageous to radially over the canister with a flange to provide standing edge, which can be attached to the canister bottom or can be formed as its protuberance. The particular advantage of this arrangement is that regardless of the tolerances that occur, the top of the canister always has a constant position inside the tube, which can be essential depending on the use of the drainage shaft according to the invention; for example, the top of the canister can have channel-shaped depressions which, after the canister has been inserted into the tube, form continuations of the undersides of the respective pipeline openings, so that as little deposits as possible form in the drainage shaft.

If necessary, a sealing ring can be inserted between the underside of the inside of the pipe wall and the canister wall; it is also possible to put a sealant between the canister and the pipe.

In principle, the described clamping fit between the canister and the pipe could be sufficient to hold the canister sufficiently in the pipe. But especially when the pipe with the inserted canister filled with the ballast material is raised to be lowered into the prepared pit, an additional fastening is particularly advantageous.

According to a preferred embodiment of the invention, the canister can be glued into the tube for fastening; the gluing can take place either preferably at the manufacturer or at the construction site; a particularly reliable attachment is achieved by welding, preferably by means of ultrasound; here the weld can be designed as a weld seam and at the same time form the seal; but it is also possible and advantageous because of the low workload to provide spot welds.

A supplementary or alternative type of fastening is that on the pipe and / or on the canister, at least one engagement strip projecting toward the other of these elements is formed, which engages in a complementary recess in the other position of the canister opposite one another in the other of these elements and either holds the canister alone in this position or holds it for so long fixed until the bond or weld is made.

When using a tube provided with circumferential grooves, the engagement bar is preferably designed as at least one preferably interrupted circumferential bar. Two circumferential strips lying one above the other are preferably provided, which engage in two adjacent ring beads of the tube and are more preferably provided approximately between half and the lower third of the side wall of the canister. In order to ensure easier insertion, the circumferential strips are not designed to be continuous, but rather as sections which each extend over only part of the circumference and are spaced apart from one another; four sections of the or each circumferential bar are preferably provided with uniform spacings and, viewed in the circumferential direction, are a little shorter than the respective spacings.

The strips are preferably provided with a bevel which faces the other of these elements, which is moved relative to this strip when the canister is inserted into the tube, while the opposite side of the strip is offset; this facilitates the insertion of the canister into the tube until the respective bar has snapped into the associated depression, but the canister is prevented from being pulled out of the tube by the step of the respective bar.

When using a tube provided with circumferential beads, these form the respective recess, while the strips are formed on the outside of the canister and are bevelled upwards, with a profile similar to a sawtooth profile in cross section.

According to an alternative embodiment of the invention, however, the chamber is not formed by a canister or other separate container, but by the lower part of the tube itself, the chamber being closable or closed by an upper and lower lid. Here, one of the lids can already be attached during manufacture or be formed in one piece with the tube, but the two lids are preferably formed separately from the tube, so that it can be decided at the construction site whether the chamber is to be filled from above or from below, i.e. with the pipe upright or upside down; it is also possible to choose the height of the top cover at the construction site according to the requirements.

According to a preferred embodiment of the invention, at least one of the lids is provided with a flange-like edge which can be formed as a circumferential flange or from separate sections separated from one another; this flange can engage in counter-recesses in the tube, preferably an annular bead. However, it may also be advantageous to arrange projections on the inside of the tube, on which the associated cover can rest.

According to a further preferred embodiment of the invention, the flange of the lower cover can be designed as a conical surface which can be placed against a complementary conical surface of the tube from below; this conical surface is preferably formed by the outside of the lower side wall of an annular bead. The flange can be glued or welded to the conical surface, but is preferably fastened with a circumferential tightening strap, which is designed similar to a barrel cover closure (tightening ring) and encompasses the flange from below and outside and the lower part of the tube from the outside and optionally from above , wherein the circumferential tightening strap bears from above against the lower side wall of an outer bead of the tube. This is the quick but reliable attachment of the lower cover on the pipe possible; the bottom cover is held by the circumferential tensioning strap so that it cannot come loose even if the tube with an already ballast-filled chamber is unskillful, e.g. unilaterally and roughly, is placed on a base or runs against the edge of the pit when it is lifted again. The circumferential tensioning strap can be quickly and easily attached both at the factory and at the construction site and, if necessary, can also be loosened again, for example in the event of incorrect planning.

It is particularly expedient to firmly connect the top cover to the tube, preferably by welding using ultrasound. The chamber is then filled with the ballast either from below, ie with the tube turned over and with the lower cover removed, or through a closable filler opening in the lower cover.

In the same way, if a canister is used as a ballast chamber, it can also be inserted upside down in the tube, that is, with the filling opening facing downwards.

When using a circumferential tensioning band or tensioning ring, it is particularly advantageous according to a preferred embodiment of the invention to insert a seal between the lower ring side wall of the tube and the flank of the lower cover, which is preferably designed as a sealing ring.

It is possible with the simplest means to fill the chamber with the ballast when the lower cover is removed and with the tube turned over, whereby considerable weights are possible for the ballast, especially when the upper cover is welded in.

After inserting the seal and placing the lower cover on it, the clamping ring is placed and tightened until the lower cover sits tightly on the seal.

The lower cover is preferably provided with stiffeners, which in turn can preferably be formed as stiffening beads which extend essentially in the radial direction and are suitable for absorbing considerable radial stresses without significantly deforming. However, the stiffeners are also preferably designed in such a way that they prevent the lower cover from bulging out even if it is exposed to a considerable surface load transversely to its surface.

It has proven to be particularly advantageous to design the stiffening beads essentially in the form of a sector, the cover preferably having a flat connecting wall between two adjacent sector-shaped stiffening beads, the width of which corresponds approximately to that of one of the stiffening beads separated from this.

Twelve stiffening beads are preferably provided.

The tips of the stiffening beads facing the center of the lower cover are preferably blunted and lie on a circle, the diameter of which is preferably about a third of that of the lower cover; the circle thus left blank in the middle of the lower lid can accommodate a filling opening.

Due to the stiffeners, the lower cover can absorb a high, radially directed tension on the one hand, which is caused by the tight tightening of the circumferential tensioning strap, as well as a high surface load resulting from the weight of the ballast.

By means of the lower cover designed in the manner described, it can therefore withstand a very high ballast weight after the tube has been erected, without forming a leak, for example, from which liquid ballast could escape.

In order to produce a particularly reliable and load-independent seal between the tube and the lower cover, according to a further preferred embodiment, an end connector is formed on the underside of the tube, which essentially has a cylindrical outer surface. When using a grooved tube, the circumferential web connecting two adjacent inner beads forms such a connecting piece when the lower ring bead is separated.

Opposite the outside of this end connector, an inner cylinder surface is formed on the lower cover which, together with the outer surface in the form of a cylinder jacket, delimits an annular gap on both sides, in which a sealing arrangement, preferably a soft sealing ring, is introduced.

This sealing ring does not need to be tight, but it can be arranged relatively loosely; the annular gap receiving it is limited upwards and downwards by the lowest ring bead of the tube or the chamber bottom surface formed by the lower cover so that the sealing ring is pressed against a gap by the prevailing pressure drop and seals it.

The invention relates not only to the drainage shaft described above, but expressly also to a method for erecting such a drainage shaft, the tube forming the tube being brought together with the ballast forming the weight to ensure the stability shortly before or during installation of the shaft can be formed as a solid body; furthermore, the method according to the invention also relates in particular to the filling of a bulk material or water to form the ballast in a container which is either formed or connected in one piece with the tube or is or was or was separable from it, and the attachment of a separate one with Ballast filled container on the pipe.

• Fig. 1 den Axialschnitt durch den unteren Teil einer ersten Ausführungsform eines erfindungsgemäßen Dränschachtes,
• Fig. 1′ den Axialschnitt durch den unteren Teil einer Variante der in Fig. 1 gezeigten Ausführungsform,
• Fig. 2 einen Axialschnitt ähnlich jenem der Fig. 1 durch eine zweite Ausführungsform eines erfindungsgemäßen Dränschachtes,
• Fig. 2′ den Axialschnitt durch den unteren Teil einer Variante der in Fig. 2 gezeigten Ausführungsform,
• Fig. 3a die Halb-Draufsicht auf einen erfindungsgemäßen Unterdeckel, der ein Element einer noch weiteren Ausführungsform der Erfindung bildet,
• Fig. 3b den Axialschnitt durch den Unterdeckel der Fig. 3a,
• Fig. 4a die Halb-Draufsicht auf einen erfindungsgemäßen Oberdeckel, der bei der Ausführungsform einsetzbar ist, die den Unterdeckel der Fig. 3a und 3b verwendet,
• Fig. 5a im Teil-Axialschnitt und in gegenüber den übrigen Figuren vergrößertem Maßstab die Befestigung eines Unterdeckels ähnlich jenem der Fig. 3a und 3b an der Unterseite eines Rillenrohrs, wie es in Fig. 1, 1′, 2 und 2′ gezeigt ist,
• Fig. 5b und 5c jeweils eine Darstellung ähnlich jener der Fig. 5a, jedoch mit jeweils modifizierter Befestigung des Unterdeckels am Rillenrohr,
• Fig. 6 den Axialschnitt durch den unteren Teil eines erfindungsgemäßen Dränschachtes, mit einem Rillenrohr, dessen unterer Teil eine von einem Ober- und einem Unterdeckel abgeschlossene Ballastkammer aufweist,
• Fig. 7 eine Halb-Draufsicht auf eine andere Ausführungsform eines erfindungsgemäßen Unterdeckels, und
• Fig. 8 den Einbau eines Dränschachtes, gezeigt am Beispiel eines Dränschachtes aus dem Stand der Technik.

The object of the invention is based on the attached, schematic Drawing explained for example in more detail; in this shows:

• 1 shows the axial section through the lower part of a first embodiment of a drainage shaft according to the invention,
• 1 'the axial section through the lower part of a variant of the embodiment shown in Fig. 1,
• 2 shows an axial section similar to that of FIG. 1 through a second embodiment of a drainage shaft according to the invention,
• 2 'the axial section through the lower part of a variant of the embodiment shown in Fig. 2,
• 3a shows the half-top view of a lower cover according to the invention, which forms an element of a still further embodiment of the invention,
• 3b shows the axial section through the lower cover of FIG. 3a,
• 4a is the half-top view of an upper cover according to the invention, which can be used in the embodiment that uses the lower cover of FIGS. 3a and 3b,
• 5a in partial axial section and on an enlarged scale compared to the other figures, the attachment of a lower cover similar to that of FIGS. 3a and 3b on the underside of a grooved tube, as shown in Fig. 1, 1 ', 2 and 2',
• 5b and 5c each show a representation similar to that of FIG. 5a, but with modified attachment of the lower cover to the grooved tube,
• 6 shows the axial section through the lower part of a drainage shaft according to the invention, with a grooved tube, the lower part of which has a ballast chamber closed off by an upper and a lower cover,
• Fig. 7 is a semi-plan view of another embodiment of a lower cover according to the invention, and
• 8 shows the installation of a drainage shaft, shown using the example of a drainage shaft from the prior art.

Figures 1 to 4 and 6 are reduced to about 1: 3 scale.

In Fig. 1, 1 ', 2 and' 2, the lower part of a grooved tube 1 made of plastic is shown, which forms a drainage shaft and above the lower part shown at least one and preferably four pipe openings offset by 90 °.

The wall of the tube 1 is formed by successive inner (2) and outer ring beads, the connecting web of two inner and outer beads each forming the bottom of the outer or inner bead bounded by these. The side walls of each inner bead 2 are inclined to one another in axial section by approximately 22 ° and form the sides of a regular trapezoid, the height of which is approximately equal to its base. All edges, especially the inner edges, are rounded.

The contour of the tube in cross-section is circular, but it could also have another cross-sectional shape that is customary in manholes, for example that of a square or rectangle, preferably with rounded corners.

In the embodiments of FIGS. 1, 1 ', 2 and 2', a canister 3 is used in the lower part of the tube 1 shown, with a bottom 5, a side wall 4 essentially complementary to the inner contour of the tube 1 and with an upper wall 6, in the middle of which a filler opening which can be covered by a cover 7 is recessed, in which the cover is preferably held non-detachably by a latching device 8 formed on the filler opening and on the filler opening.

If the canister 3 reaches as far as the pipeline mouths, flow-guiding designs similar to the channels 16 shown in FIG. 4 can be provided in its upper side 6 and in the cover 7. In addition, the top 6 of the canister 3 and the lid 7 are so smooth that they give as little cause as possible to form deposits; in the exemplary embodiments shown the top 6 of the canister 3 is flat; the lid 7 is arched flat in the embodiments of FIGS. 1 and 2, on the other hand in the embodiments of FIGS. 1 'and 2' completely flat and embedded in the locking device. The lid 7 of each embodiment merges into the top 6 without a paragraph.

The side wall 4 of the canister 3 is inclined in the axial sections shown relative to the envelope surface of the inner wall of the tube 1 by about 0.5 °, so that the canister 3 can be clamped in the lower part of the tube 1 like a conical plug.

The bottom 5 of the canister 3 shown in FIGS. 1 and 2 'is arched inwards and extends only to the side wall 4, so that the canister 3 can be pushed practically as far into the tube 1 as is necessary for the flow conditions in the drainage shaft is. It is fundamentally also possible to push the canister of FIG. 1 out to the top of the tube 1, insofar as this is not impossible because of the conical design of the canister side wall.

If the canister 3 of Figure 1 is filled with ballast material, e.g. with water and gravel, then the weight of the ballast material pushes the bottom 5 of the canister 1 downward, so that this bottom in turn widens the side wall 4 of the canister and thus produces a strong clamp fit of the canister 3 in the tube 1.

2 and in the respective embodiment shown in the left part of FIGS. 1 'and 2' has a flat bottom 5, which is in the embodiments of FIGS. 2 and 1 'to form a peripheral flange 9 and 9 respectively 'Extends radially beyond the side wall 4. The peripheral flange 9 or 9 'is against the bottom of the tube 1 from below.

The peripheral flange can be designed as a solid strip 9 projecting beyond the side wall 4 like a hat brim, as shown in FIG. 2, or it can be of a bead-like protuberance on the lower one

End of the side wall in the form of an everted peripheral bead 9 'be formed, as shown in Fig. 1'.

The two flange shapes 9, 9 'can be used in any of the described embodiments.

As far as no peripheral flange is used, the transition between side wall 4 and bottom 5 can be rounded only a little, as shown in Fig. 1, or with a large radius, as shown in Fig. 2 '.

In the embodiments of Figures 1 and 1 'are at the middle height of the side wall 4 and approximately in the middle between this height and the bottom 5 of this side wall 4 on the outside of engagement strips 11a (top) and 11b (bottom); 1, four engagement strips 11a, b are provided at each height, which are distributed at equal intervals over the circumference of the side wall 4 and each extend over an angular range of approximately 40 °. The individual engagement strips 11a lie exactly above the individual engagement strips 11b. 1 ', the upper and lower engagement bars 11a, 11b each extend over the entire or substantially the entire circumference of the side wall 4 of the canister 3.

The top of each engagement bar 11a, 11b has a bevel 12; otherwise, the engagement strips are dimensioned such that they can come into loose engagement with the inner beads 2 of the tube 1 and when inserting the canister 3 into the tube 1 from below it can widen or deform it by means of the bevels 12 so that the engagement strips can come into engagement with a desired inner bead 2.

Because of the undersides of the engagement strips 11a, b, which drop steeply to the side wall 4 of the canister 3 and lie snugly against the lower side surfaces of the respective inner beads 2, it is impossible to to remove the canister 3 down from the pipe.

The canister 3 shown in FIG. 2 has a smooth side wall 4 which is ultrasonically welded to the webs between adjacent inner beads 2.

Instead of a canister 3 inserted into the tube 1 from below, the chamber for receiving ballast material can also be formed in that the underside of the tube 1 downwards through a lower cover 13, 13 'or 13˝ and upwards through an upper cover 14, 14 'is divided, which are shown in Figs. 3, 4 and 6 and which are preferably both made of plastic.

The lower cover 13 shown in FIG. 3 has a radial circumferential flange and stiffening beads 15 which are evenly distributed over the circumference and bulge upwards. The radial peripheral flange is inserted into a tube of the type shown in FIGS. 1 and 2 tilted from below and then pressed in the radial position so that the radial peripheral flange engages in an inner bead 2.

It is also possible to insert the lower cover 13 into the tube 1 from below in such a way that the bevelled outer flanks of the stiffeners 15 bear against the inner wall of the tube; a circumferential tensioning band similar to that of FIGS. 5a, b and c is then applied over the radial circumferential flange and the adjacent outer bead of the tube 1, which compresses and holds the lid 13 and tube 1 together.

Fig. 4 shows an upper cover 14, which has in its upper side two mutually perpendicular, flat channels 16 which, after installation of the upper cover 14 in the pipe 1, reach the underside of pipeline inlets, continue the flow channel formed by them and the formation of Prevent deposits.

On the underside of the top cover 14 is a down he extending circumferential collar, which serves for stiffening and on the outside or preferably lower edge of a narrow radial flange can be arranged, which can be pressed into an inner bead 2 of the tube 1.

In Fig. 5a, another embodiment of a lower cover 13 'is shown; this lower cover 13 'has a substantially flat bottom, the circumference of which is bent upwards to form a short cylindrical connecting piece 19. The upper end of the connector 19 is extended by a flange 17 which extends conically upwards and outwards. The cone angle is chosen so that the flange 17 bears flat against a tube wall section 18 forming the lower side wall of an annular bead 2 from below.

This wall section 18 merges downwards into a short, cylindrical connecting piece 20, which is opposite the connecting piece 19 to form an annular gap in which a sealing ring 22 is arranged.

A circumferential tensioning strap 21 with a trapezoidal cross-section comprises on the outside from below the flange 18 and from above the upper side wall of the lowermost inner bead 2 of the tube 1 and holds all of these parts firmly and under tension.

Also in the embodiments of FIGS. 5b and 5c, the circumferential tightening strap is shaped in the manner described above in connection with the embodiment of FIG. 5a.

In both embodiments, however, the tube 1 ends downward with the wall section 18, which the flange 17 is opposite.

This flange 17 of the lower cover 13˝ is formed like that of the lower cover 13 'in the embodiment of Fig. 5a; towards the inside of the lower cover, however, in the last-mentioned exemplary embodiments, there is an outwardly bulging circumferential ring bead which limits the stiffeners 15 'towards the outside and projects beyond them downwards; the bottom of these stiffeners facing the upper cover 14 extends parallel to the overall extent of the lower cover 13˝; the stiffeners 15 'end just before the center of the lower cover 13˝.

The said circumferential ring bead not only serves to stiffen the lower cover 13˝, but also takes up the length tolerances that occur when the tube 1 is cut off, so that a reliable seal is always guaranteed.

In the embodiment of Fig. 5b, an annular disc-shaped seal 22 'is inserted between the flange 17 and the tube wall section 18.

In the embodiment of FIG. 5c, the flange 17 and the tube wall section 18 rest against one another in a flat and sealing manner; preferably at least one of the lower cover 13 'and tube 1 is formed from a material which is sufficiently flexible that the pulling-up of the circumferential tensioning strap 21 can press these mentioned parts against one another.

In Fig. 6 the lower cover 13˝ is shown with the attachment of Fig. 5c; the upper cover 14 'corresponds substantially to that of Fig. 4a, but is formed on its peripheral edge so that it bears from below against the inner edge of an inner bead 2, wherein an ultrasonic welding point 10 is formed at the contact point, which the Upper cover 14 'fixed in the tube 1.

In Fig. 7, the lower lid 13 ', 13˝ shown in Figures 5a to 6˝ is shown in the semi-plan view; one can clearly see that of relatively narrow, radial with a mutual angular distance of preferably 60 ° outwardly extending stiffeners 15 'divided bottom, which has relatively extensive, flat surfaces, whereby the drainage shaft according to the invention receives a stable position. In addition, the flat surfaces are well suited to include labels, such as an instruction manual.

The stiffeners 15 'cooperate with the edge formation 17, 23 and thus achieve that the lower cover 13', 13˝ shown is able to withstand considerable ballast weights without bulging.

8 shows a known drainage shaft after the installation, which corresponds to that of the drainage shaft according to the invention. The known drainage shaft is formed by a tube 1, the top of which is closed by a cover 32 and in the underside of which there is a fixed insert which is poured with concrete 37 and which is seated on the bottom 35 of an excavation 34 which is recessed in the ground. The upper edge of the cover 32 is flush with the earth's surface 33.

37 pipes open into the pipe 1 just above the concrete weight and are connected to connecting pieces preformed in the wall of the pipe.

In order to complete the installation of the drainage shaft, the excavation 34 is filled with gravel, soil or the like.

As can be seen, the pipe 1, even if it is formed in two parts, as in the example shown, is difficult to transport and handle because of the fixed concrete weight 37.

Claims (17)

1. Drain manhole in a preferably corrugated tube (1), preferably of plastic, in the wall of which openings are formed for connection to at least one pipe and on the bottom part of which a weight is arranged to increase stability, characterized in that the weight is constructed as a chmaber (3; 13, 14) separate from the tube (1) and mounted thereon or therein, filled with ballast material.

2. Drain manhole according to claim 1, characterized in that the ballast material is bulk material and/or a liquid.

3. Drain manhole according to one of claims 1 or 2, characterized in that the chamber is formed by a container (3) separate from the tube (1) and preferably closable.

4. Drain manhole according to claim 3, characterized in that the container is formed as a container (3) fitting into the lower part of the tube (1) and preferably sealingly insertable, closed on the upper side by means of a cover (7).

5. Drain manhole according to claim 4, characterized in that the cover (7) has a substantially smaller diameter than the canister (3) and can be locked into an opening in the upper closure wall (6) of the latter (locking construction 8).

6. Drain manhole according to claim 4, characterized in that, of the facing surfaces of tube (1) and canister (3) at least one is constructed slightly conical in such a manner that a clamping sealing seating of the canister (3) in the tube (1) is achievable.

7. Drain manhole according to one of claims 4 to 6, characterized in that the bottom (5) of the canister (3) substantially blanks off the underside of the tube (1) in flush manner.

8. Drain manhole according to one of claims 4 to 6, characterized in that the canister (3) has a protruding bottom edge (9) in the manner of a flange which applies from below against the underside of the tube (1).

9. Drain manhole according to claim 8, characterized in that a sealing arrangement is provided between the bottom edge (9) and the underside of the tube (1).

10. Drain manhole according to one of claims 4 to 9, characterized in that the canister (3) is glued or preferably welded to the tube (1), (welding points 10).

11. Drain manhole according to one of claims 4 to 10, characterized in that on the outside of the canister (3) at least one strip (11a, 11b) protruding and extending over at least one part of the periphery, and/or recessed bead is formed which may be brought into engagement with at least one bead (2) and/or strip complementarily formed in the tube (1).

12. Drain manhole according to claim 11, characterized in that the strip (11a, 11b) has in cross-section a saw-tooth profile so bevelled (bevelling 12) that the introduction of the canister (3) into the tube (1) is facilitated, while the extraction is made difficult.

13. Drain manhole according to one of claims 1 or 2, characterized in that the chamber which is peripherally defined by the tube (1) is closable upwards by an upper cover (14) and downwards by a lower cover (13), of which two covers at least one is designed separate from the tube (1) and can be inserted into, or placed onto, the latter.

14. Drain manhole according to claim 13, characterized in that the cover(s) (13, 14) insertable into the tube (1) has/have a flange-like protruding circumferential edge (17) which can be brought into engagement with a peripheral bead (2) of the tube (1).

15. Drain manhole according to one of claims 13 or 14, characterized in that the lower cover (13′) has a conical flange (17) which can be applied from below against a conical surface (18) on the underside of the tube (1), and in that the flange (17) and the bottom part of the tube (1) are encompassed and held together by a peripheral tightening strap (21).

16. Drain manhole according to claim 15, characterized in that the lowermost end of the tube (1) is formed as a short circular-cylindrical end piece (20) the outside of which lies opposite a cylindrical inner surface (19) of the bottom cover (13′), and in that an annular seal (22) is inserted between these oppositely-lying cylinder surfaces.

17. Drain manhole according to claim 14, characterized in that a seal (22) is inserted between the lowermost annular side wall (flank 18) of the tube (1) and the flank of the lower cover (17).

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