| 1. | A manhole shaft that comprises at least two mutually welded together ringshaped sleeves (20,21,22), they are formed with a number of ringshaped waves (7), with each a crest (8) and a trough (9), which defines an axis characterised in that in at least one to at least one sleeve (20,21,22) belonging wave crest (8) and/or trough is formed at least one support chamfer (23,24) that extends across the waves (7). |
| 2. | A manhole shaft according to claim 1 characterised in that, to at least one sleeve (20, 21,22) belonging wave crest (8) and/or trough (9) is formed with a number respectively external (23)and internal (24) support chamfers, which with interval are divided along respectively periphery of each sleeve (20,21,22). |
| 3. | A manhole shaft according to claim 1 or 2 characterised in that, the internal (24) and/or external (23) support chamfers two and two are placed on equal distances along the periphery of each sleeve (20,21,22). |
| 4. | Manhole shafts according to claim 2 or 3 characterised in that, the internal (24) and/or external (23) support chamfers are angle dislocated round the axis in relationship to each other. |
| 5. | Manhole shafts according to one of claims 2,3 or 4 characterised in that, the internal (24)and/or external (23) support chamfers are angle dislocated one to a half interval answering angle in relationship to each other. |
| 6. | Manhole shafts according to one of claims 25 characterised in that, the internal (24) and/or external (23) support chamfers overlap each other radial. |
| 7. | Manhole shafts according to one of claims 26 characterised in that, at least one sleeve (20,21,22) is welded together with an other sleeve (20,21,22) along an edge at the top of a wave (7). |
| 8. | Manhole shafts according to one of claims 27 characterised in that, it encloses a conical top section (22) in form of an upper sleeve (22) and at least one principal cylinder formed underlying middle section (21) in form of a middle section (21). |
| 9. | Manhole shafts according to one of claims 18 characterised in that, the manhole encloses one under the middle section (21) placed bottom section (20) with a berm (11), a bottom outlet, at least a small pipe (12,15,16,17) and a lower sleeve (20). |
| 10. | Manhole shafts according to claims 7 characterised in that, at least one small pipe (12, 15,16,17) of the bottom section reaches through the lower sleeve (20). |
It is a well-known problem, that manhole shafts, consisting of elements, which are jointed together with gaskets, are exposed at the joints.
The manhole is constructed in sections, starting with a bottom section with prefabricated bottom grooves, and then continuing with a number of prefabricated middle rings and a conical top piece and eventually one or several top rings. In the joints between each section or ring, gaskets are placed too achieve good tightening. Furthermore are the joints between the bottom grooves'inlet and outlet pipes provided with gaskets around the joint for the belonging bottom sections'inlet and outlet openings.
Leaky manholes will partly cause trickling of ground water and by that dilution of the concentrated waste water, that causes an increasing pressure on the following pump stations and cleaning plants, and partly cause unsuitable trickling of waste water to the surrounding soil in areas that serves as well places and extract places of drinking water.
Leaky manholes are also known from sleeves with welded elements, which are reinforced with screw shaped corrugations, in that the edges of the inlet and outlet of the screw shaped corrugations are smoothed and therefor not easily suitable for example welding butt to butt. This welding method is known for example from the Swiss patent CH 653 951.
One known manhole from a British patent GB 2,217,744 is made of polyethylene and shaped with successive screw shaped corrugations. The screw shaped corrugations have a further disadvantage, in that the sleeves are willing to get loose in the soil, since they turn with axial pressure and heat expansion.
It is also known however that sleeves with ring-shaped waves reinforce the, by concern to material consumption proportionally, thin walls. The location of the waves permits for example the sleeves easy and safe be welded together butt to butt. The waves also serve to anchor the sleeves in the soil.
The wave shaped sleeves form however some kind of a pair of bellows, that deforms in and out, when they for example are affected by the pressure from a lorry, that passes over a cover plate over the manhole. Consequently is the soil moved around the waves of the sleeve, and by time are their grips in the soil loosened.
In addition manholes, which are constructed of plastic material can be fragile due to age.
Older plastic manholes will therefore have an increased tendency to crack or break by them self, when they are exposed for the above mentioned pressure or dislocations in the soil-layers.
A first feature of present invention indicates a manhole shaft of a kind by way of introduction with wave formed sleeves, that easily are welded together.
A second feature of present invention indicates a manhole shaft of a kind bay way of introduction, which is stable against axial pressures from for example lorries driving over.
A third feature of present invention indicates a manhole shaft of a kind bay way of introduction, which secure the sleeves a safe grip of the surrounding soil against axial dislocations as well as angle dislocations.
A fourth feature of present invention indicates a manhole shaft of a kind bay way of introduction, which has a simple construction, which is able to produce for a relatively low price.
A fifth feature of present invention indicates a leakage free manhole shaft.
The new and singular, with by which this is achieved by the present invention, is that at least one to at least one sleeve belonging wave crest and/or trough give shape to at least one prevent chamber, that extend across the waves.
Thereby obtains advantageous, that the manhole is possible to resist axial pressure, which it is exposed for, when for example a lorry passes a top cover plate made to close the manhole, without getting axial deformations, that may move the surrounding soil and thereby loose the sleeves. The waves further secure the sleeves in a firm grip in the surrounding soil against axial dislocations and prevent the sleeves to turn The sleeves of following invention can be anchored so solid in the soil, so they not will turn or dislocate when under pressure, and the risk for strain and stretch breaks can be reduced and thereby can non tightness be considerable reduced.
A particular effective support is achieved, in any case when each to a sleeve belonging wave crest and/or a trough are shaped with a number of external and internal support chamfers, that are distributed with interval along the periphery of each sleeve.
When the internal-and/or the external support chamfers are angle dislocated round the axis in relationship to each other with for example one to a half interval answering angle achieves an even distribution of the pressure along the periphery of the welded sleeves.
The internal-and external support chamfers can with advantage overlap each other radial, thereby the welded sleeves are permitted to flexible fit to a hole in the ground that is not completely round.
The sleeves can by advantage be welded together with help of butt to butt welding along free edges, which are shaped in the ring shaped wave crests, and are in a level, that stands perpendicular to the axis, then the opposite edges can be brought to fit together, and the joint can thereby be made dense. The butt to butt welding can especially take place, when two wave crests, that will be welded together, are formed without support chamfers.
Often a manhole shaft has a top section, a middle section and a bottom section. With an advantageous design can each of the top and middle section be made of a upper sleeve and a middle sleeve, when the bottom section can be surrounded by a lower sleeve and also advantageous enclose a berm, a bottom outlet and at least one small pipe. Thereby achieves a simple, price cheap and in the same time strong and stable construction that is easy to put in a manhole trench.
The bottom section can advantageous be moulded with at least one small pipe, that for example begins from the bottom furrow of the bottom section and extends through the lower sleeve. The inlet and outlet pipes can easily and dense be closed by welding, welding butt to butt.
The sections of the manhole shaft can advantageous be made with rotation moulding in a, for the section made, mould form. A preferred production material for manhole shafts is for example polyethylene (PE), preferred a HD-PE (high density polyethylene) or a polypropylene (PP) in that these materials easily can be welded butt to butt and as well are non polluting in relation to the surrounding ground water. The invention is however not limited to these polymers, in that the extent of the protection encloses each material, that can be used for rotation moulding, can be welded butt to butt and bring sufficient strength and flexibility for the manhole shaft.
The manhole made of the sections with pipe connections appears like a comparatively flexible unit, which keeps its tightness in the joints with proportionately great mechanical pressure and/or settles, in the surrounding soil or friction material.
By making the bottom sections as a unit, are direct collections of pipes avoided between the manhole wall and the pipe connections, and the distance from the joints of the manhole wall between the pipe connection and the small piece of pipe gives greater security against leakage.
To be able to prevent trickling of water at a increased ground water level can the conical top section advantageously also comprise a cover plate, that is assembled dense on the top
The invention is explained further below, describes only examples of performances and additional advantageously characteristics and technical features with reference to the drawings, where Fig. 1 shows, seen from the side, an exploded view of a manhole shaft of present invention, with a vertical section of the bottom section.
Fig. 2 shows the same but welded, Fig 3a shows a manhole shaft from above without top section in a first embodiment for the bottom outlet, Fig. 3b shows a manhole shaft from above without top section in a second embodiment for the bottom outlet, Fig. 3c shows a manhole shaft from above without top section with a third embodiment for the bottom outlet, Fig. 3d shows a manhole shaft from above without top section with a fourth embodiment for the bottom outlet, Fig. 4 shows, from the side, a manhole in present invention, which is arranged as sand trap without trap top cover plate, Fig. 5 shows, seen from the side, an exploded view of a second form of a manhole shaft of present invention, Fig. 6 shows the same welded together, Fig. 7 shows the form shown in fig. 6 without top cover plate, seen from above, where the support chamfers not overlap each other, and
Fig. 8 shows the form shown in fig. 6 without top cover plate, seen from above, where the support chamfers overlap each other.
Fig. 1 shows, seen from the side, an exploded view in a first form of execution of a manhole shaft of present invention.
The manhole shaft encloses a sleeve to a for a trench and is in its whole indicated by number 1, and it consists of a ring formed bottom section 2, a ring formed middle section 3, a conical top section 4 and a cover plate 5, that optional can be supported by an unloading ring 6. The bottom section 2, the middle section 3 and the top section 4 are shaped with a number of ring formed waves 7, with a number of crests 8 and troughs 9, that define a axis around which the waves 7 principally are placed coaxial. The waves 7 form a corrugated enclosed wall in the manhole shaft 1. The ring formed waves contribute to anchor the manhole in to the surrounding soil, when friction material, as soil or gravel, which is filled around the manhole 1 compress and press in between the wave troughs 9 and fix the manhole in to the trench.
The bottom section 2 has a lower sleeve 2, which is rotation moulded as a unit together with a bottom outlet 10, a berm 11 and a small pipe 12,15. The bottom outlet has a preferable slope of 15 % o. The necessary connections for the bottom section 2 can easy and simple be put together with welding butt to butt, as well as the simplest sections with above mentioned way can be put together to a unit with welding butt to butt, which produce a dense manhole shaft, which effectively stops in and out trickling.
The conical top section 4 ends up with a manhole 13, which has locking means 14, supposed to interfere with not shown corresponding locking means on the cover plate 5.
The locking means can as shown be faucets4, but can as well be threaded internal. As an alternative can the cover plate encloses the manhole and the locking means can in this case by advantage be mounted along the outside upper periphery of the manhole and along the inside periphery of the cover plate.
When using a not shown gasket or gasket ring between the cover plate 5 and the manhole 13, can the joint between the top section 4 and the cover plate 5 be made dense, and the risk for trickling of abundance water are eliminated.
The by sections 2,3 and 4 jointed manhole shaft 1 is in its welded completeness shown in fig. 2. The top section 4 is welded butt to butt together with the middle section 3 along the line Al-Al, and the middle section 3 is further welded butt to butt together with the bottom section 2 along the line B1-B1 at the top edge of two wave crests 8.
Fig. 3a, b, c and d, seen from above, show different embodiments for the bottom outlet in a manhole shaft 1 without top section 4.
In fig. 3 a is an even bottom outlet shown, with two small pieces of pipes 12,15.
In fig. 3b is the bottom outlet shown with totally three small pieces of pipes 12,15,16 with consideration taken to the arrow in the figure, showing the angled direction of flow, an additional small piece of pipe 16 is the added form of execution in comparison with fig.
3a.
The bottom section shown in fig. 3c has totally four small pieces of pipes 12,15,16,17 and fig. 3c, answers principally to the form of execution in fig. 3b, with the difference that an other small piece of pipe 17 is added.
The form of execution showed in 3d answers principally to the form of execution in fig.
3c, with the difference that the small piece of pipe is undivided.
At rotation moulding can any desirable number of small pieces of pipes be shaped in the bottom section, from which the small pipe pieces can be closed after the rotation moulding. Inside the limitations of the invention can the angled small pieces of pipes 12, 15,16,17 take any angle in relation to the even bottom outlet 14.
At erection of the manhole a necessary number of the small pipes are opened, and the
in situ, if it will arise needs for additional pipe connections. Inside the limitations of known technique may open pieces of pipes without pipe connections be plugged and sealed to prevent leakage.
Fig. 4 shows a manhole 18 of present invention, with a looked manhole section 19, where the manhole in this case is formed as a manhole with a sand trap 18, where the outlet 10, with the small pipes 12,15 are placed at a distance from the bottom of the manhole. In the bottom section 19 is a volume defined as a collecting chamber for particle material, this prevents the material to store in the pipe connections and outlets.
The top section 4 is welded butt to butt with the middle section 3 along the line A2-A2, and the middle section 3 is welded butt to butt with the bottom section 19 along the line B2-B2, as the butt to butt welding is made by advantage in two wave crests 8.
The exploded view in fig. 5 showing a preferred form of execution of a manhole shaft of present invention is shaped as the embodiment showed in fig. 1 with three sleeves in shape of a bottom section 20, a middle section 21 and a conical top section 22.
This preferred second form of execution has at least one external support chamfer 23 in at least one wave crest and at least one internal support chamfer 24 in at least one wave trough 9, where the support chamfers are placed across the waves 7.
In fig. 5 and 6 is shown five support chamfers 23 in each wave crest 8 and four support chamfers 24 in each wave trough 9 divided on equal interval distances along the periphery of each sleeve 20,21,22 and the internal support chamfers 24 are angle dislocated round the axis in relationship to the external support chamfer 23, thus is the distance between a external support chamfer and an internal chamfer at this occasion the same along the whole periphery.
As best shown in fig. 6 are the sleeves jointed in form of the conical top section 22, the middle section 21 and the bottom section 20 to a dense unit with help of butt to butt welding along the lines A3-A3 and B3-B3 at the top edge of two wave crests 8 without
The anchoring material, which surrounds and holds the manhole stores preferably in the support chamfers 23,24 of the waves 7 sleeves 20,21,22 in the trench and the vertical direction of the manhole, and prevents that the sleeves turn and settle of load and mechanical influence.
As shown in fig. 7 has the form of execution in fig. 6 support chamfers 23,24, which not radial overlap each other.
In the embodiment of a manhole shaft shown in fig. 8 of present invention overlap the support chamfers each other, and this embodiment for the present invention is immovable stored in the trench. Both axial movements, dues to settling or temperature changes and vertical compression resist so much, that the risk for pressure collapse and leakage are eliminated.
Preferred manhole diameters for a PE or a PP manhole are 600 mm, 1000 mm, 1250 mm and 1550 mm, where the manholes can be prefabricated as finished butt to butt welded units eventually with tighten top cover plate.
In the representative case stretches a small pipe through the lower sleeve, and all small pipes are therefore made earlier on the bottom section and enclosed of a corrugated sleeve, which preferably is made with support chamfers in combination of the wave formed wall cooperate to prevent that the manhole turns or settles due to mechanical influences.
A manhole shaft with such a formed bottom section is also very easy to put correct in the trench.