WO2001040590A2

WO2001040590A2 - Access means for a pipe system

Info

Publication number: WO2001040590A2
Application number: PCT/NL2000/000881
Authority: WO
Inventors: Peter Frederik Marinus Johan Van Basten
Original assignee: Bach B.V.
Priority date: 1999-12-01
Filing date: 2000-11-30
Publication date: 2001-06-07
Also published as: WO2001040590A3; AU2715401A; NL1013710C2

Abstract

Access means (2) for a pipe system (1) that is separated from a surface (4), comprising an access pit (2), in which a chamber (26) is present which is open on a first side of the access pit so as to enter into open communication with the pipe system. The access pit (2) includes a reclosable cover (21) on a second side, which is intended to be positioned at least near the surface (4) and which provides access to the pipe system (1) via said chamber (26) in its open position.

Description

ACCESS MEANS FOR A PIPE SYSTEM

The present invention relates to access means for a pipe system that is separated from a surface. Said pipe system is intended for conveying a fluid which is passed therethrough, whether or not under pressure. In this regard it is noted that although the term fluid is sometimes interpreted in a semantically narrow sense in fluid dynamics as limited to liquids and gases only, within the framework of the invention this term is understood to include flows of solid matter particles and combinations of various conditions as well. The invention thereby relates in particular to access means for a pipe from a sewer system. In a sewer system the fluid will usually consist of a combination of liquid and solid waste products .

A problem that occurs in practice when unblocking sewer systems of houses and other buildings, in particular outside said houses or buildings, is that the exact location where access can be gained to the sewer is hardly ever known. Although special intermediate parts, so-called boundary pieces, which can provide access via a detachable cover, are usually incorporated in the service pipes, the location of said intermediate parts under the surface level is not always immediately clear. Consequently, a considerable amount of digging is often inevitable before the unblocking operation can be started. The same applies with regard to inspections of the sewer system, which may or may not take place periodically. Not only does this involve an unnecessary great deal of work, but in many cases said digging cannot take place without causing damage to plants and paving. The latter is all the more the case when access needs to be gained to an underfloor pipe, in which case it may even be necessary to break up the floor.

Consequently, it is an object of the present invention to provide access means for a pipe system that is separated from the surface, which access means obviate the above- described problems at least to a certain extent.

In order to accomplish that objective, the access means for a pipe system that is separated from a surface comprise an access pit, in which a chamber is present that is open on a first side of the access pit so as to enter into open communication with the pipe system, and which includes a reclosable cover on a second side, which is intended to be positioned at least near the surface and which provides access to the pipe system via said chamber in its open position. The access pit lies at the surface itself, therefore, whilst the pipe system is separated therefrom. As a result, the location where access can be readily gained will usually be directly visible. The access pit is for example incorporated in the paving with its cover, or it lies at ground level. Usually no searching or digging will be required in order to find the access means, therefore. When the cover is open, unblocking or inspection means can be directed to the pipe system via the chamber in order to subsequently carry out the intended work therein. The invention is not limited to sewer systems for that matter, it is also suitable for use with other types of pipe systems, such as water mains pipes, industrial liquid and gas pipes and transport pipes for solid bulk goods and the like.

In one special embodiment of the invention the access means are characterized in that the access pit, on a first side thereof, includes at least a part of connecting means for realising an at least substantially fluid-tight connection to a connecting pipe of the pipe system. The connecting pipe provides the required connection to the pipe system. The connecting means may have numerous forms. In another special embodiment, however, the access means are characterized in that said connecting means comprise a spigot part and a socket part being at least substantially complementary thereto, one part being formed on the first side of the access pit and the other part being present at one end of the connecting pipe. The end of the connecting pipe can thereby constitute the spigot part, but alternatively the pipe may be slightly narrowed for that purpose. In both cases the socket part will be formed on the aforesaid first side of the access pit. Conversely, also the wall of the chamber of the access pit, for example, whether or not narrowed, can form the spigot part, with the socket part being formed on the connecting pipe. In all cases a very simple and practical manner of putting together the access pit and the connecting pipe is provided, therefore. In this regard one preferred embodiment of the connecting means is characterized in that the spigot part and the socket part fit together with the interposition of a flexible ring so as to allow fluid- tight movement in axial direction of the parts relative to each other. Not only does such a ring obviate the need of providing a glued connection between the two parts, but the connection between the two parts, which thus remains permanently movable in axial direction, makes it possible to offset some degree of setting of the pipe system, thus avoiding fracture and other adverse effects. Thus a saving can be achieved in that it is not necessary to provide an expansion piece, which would otherwise be separately required for this purpose.

A special preferred embodiment of the access means is according to the invention characterized in that the cover includes an interior part comprising a first space, which is in open communication with the chamber, and a second space, which is in open communication with the outside air, and in that the two spaces are separated from each other by a valve which bears on a valve seat in an at least substantially fluid-tight manner so as to shut off the first space, but which is lifted from the valve seat under the influence of an under-pressure in the first space in comparison with the second space so as to open a fluid connection between the first space and the second space. In this embodiment the access pit not only provides access to the pipe system, but it also provides stack venting in case a sub-atmospheric pressure should develop in the pipe system. Such a sub-atmospheric pressure may for example develop when a large amount of fluid is transported through the pipe system within a short period of time. The fluid itself thereby acts more or less as a piston, as it were, which creates an under-pressure behind itself, which under-pressure subsequently opposes said transport. In order to avoid this, the valve opens in that case so as to eliminate the under-pressure thus created.

Now that the access means according to the invention will be present at the surface level, a further embodiment thereof may be of importance, which further embodiment is characterized in that the cover can be locked in position. Locking the cover in position makes it possible, in spite of the position of the access means at surface level, to prevent unauthorized persons from gaining access to the pipe system too easily.

In another special embodiment the access means are characterized in that the chamber is connected to the pipe system through the interposition of a connecting pipe, and in that the connecting pipe extends from a cover of an intermediate part that is incorporated in the pipe system. The intermediate part may be incorporated in the pipe system in advance, so that the access means can easily be added at a later stage. More particularly, in the case of a sewer system the intermediate part comprises the same element that was so far used as a boundary piece in order to gain access to the pipe system at a later stage. This existing element has a closed cover, which can easily be removed. By removing this cover and exchanging it for one from which the connecting pipe can extend, it will be very easy to implement the present invention in existing situations. For easy fitting, another embodiment of the access means is characterized in that the cover includes at least a part of connecting means for realising an at least substantially fluid-tight connection to a connecting pipe.

In another special embodiment the access means are characterized in that the cover extends at an angle with respect to a plane that is enclosed by a circumference thereof in the direction of the connecting pipe extending therefrom, and more in particular in that the angle of the cover varies between 30° and 60°. This angle of the cover provides more interior space, for example for manoeuvring unblocking or inspection means towards the pipe system. This is important in particular when unblocking or inspection means are to be manoeuvred into the pipe system through a right angle in the intermediate part. In addition, the sloping cover helps to dissipate forces acting thereon in an underground situation. Said forces may for example result from settling of the ground, and not infrequently they cause an underground pipe system to fracture or break down otherwise. In view of this, the cover is preferably not flat but formed with sloping, concave sides.

In another embodiment the access means are characterized in that the chamber is connected to the pipe system through the interposition of a connecting pipe, and in that said connecting pipe extends from a pipe bend that is incorporated in the pipe system. This embodiment is in particular suitable for use in a sewer system wherein a house connection is realised through the foundation of a house. Near the front wall of the building the sewer is still positioned relatively close to the surface level, and via the bend it immediately goes down to a lower level. Preferably, a possibility to gain access to the sewer is realised in said bend, which possibility is provided by the present embodiment. In order to make it easier to enter the pipe system inside the house via this bend, another embodiment of the access means is characterized in that the bend comprises an internal shoulder, which extends into the bend on a side facing away from the connecting pipe. The shoulder thereby provides a perceptible stop, against which the unblocking means or inspection means strike upon being led inside. At that moment the operator knows that a bend towards the inside must be negotiated, which he or she can subsequently do. In the absence of such a perceptible stop the operator will remain uncertain longer as regards the distance from the bend to the access pit.

Another preferred embodiment of the access means according to the invention is characterized in that the chamber includes at least a part of fixation means for attachment to a wall plate. The wall plate is mounted on the front wall of a building in advance, after which the access pit can be fixed thereto by means of said fixation means. In this respect a special embodiment of the access means is characterized in that a flanged edge is present on an upper side of a wall of the chamber, and in that said fixation means comprise an edge extending downwards from said flanged edge, which edge is capable of engaging behind a part of the wall plate, and more in particular in that said fixation means comprise a snap member which is capable of effecting a snap connection between the chamber and the wall plate when said chamber is placed against said wall plate.

The invention will now be explained in more detail by means of two embodiments thereof and the appended drawing. In the drawing:

Figure 1 is a perspective view of a first embodiment of access means in accordance with the present invention, which are incorporated in a pipe system; Figure 2 is a detail view of the intermediate part including the cover that is incorporated in the pipe system of Figure 1; Figure 3 is a perspective view of the access pit of the access means of Figure 1; Figure 4 is a partially cut-away view of the access pit of Figure 3;

Figure 5 is a cross-sectional view of the access pit of

Figure 3; Figure 6 is a perspective view of a second embodiment of access means in accordance with the present invention, which are incorporated in a pipe system; and Figure 7 is a detail view of the bend portion in the pipe system of Figure 5. The figures are purely schematic views for that matter, and they are not drawn to scale in all cases. In particular some dimensions are strongly exaggerated for the sake of clarity in the figures. Parts corresponding to each other are as much as possible indicated by the same numerals in the figures.

Figure 1 shows a part of a pipe system that forms a sewer system of a house or other building. The figure thereby shows house connection pipe 1 as it exits the house for being connected to the public sewer system. Sewer pipe 1 includes access means in the form of an access pit 2 and a connecting pipe 3. Although sewer pipe 1 is separated from the surface, in this case the ground surface comprising paving 4, the access means according to the invention nevertheless provide access to the sewer system from said level. For that purpose the access pit 2 comprises a reclosable cover 21, which is incorporated in the paving and which can be opened so as to gain access, via connecting pipe 3, to the pipe system 1 that lies deeper in the ground.

The connection between access pit 2 and connecting pipe 3 has been realised through the use of connecting means in the form of a socket part 22 formed on the underside of the access pit and a spigot part in the form of end of the connecting pipe 3 that fits therein. The connection has been effected without the use of glue, and yet it is completely airtight and watertight because a flexible ring disposed in the socket part provides the desired seal.

Said ring is fixed in position in an internal groove (not shown) in the socket part and allows some movement in axial direction of the connecting pipe 3 in socket part 22. As a result of this the connection remains movable, so that the system is better able to withstand possible subsiding or setting of the pipe system 1 in any other way.

The access pit 2 is fixed to the outside wall 6 of the house by means of a wall plate 5. To this end access pit 2 is provided with fixation means in the form of an edge extending downwards from an upper surface thereof, which edge engages behind wall plate 5, as will be described in more detail hereafter.

Connecting pipe 3 is coupled to the pipe system 1 by means of a intermediate part 7. Said intermediate part 7 comprises a base 70 including an entrance 71 and an exit 72 as well as a cover 73. Base 70 corresponds at least substantially to that of a normal boundary piece, such as the one that has been used so far for providing access to a sewer system. Within the framework of the present invention cover 73 has been significantly modified, however. Instead of being purely a closing cover, in this case the cover comprises connecting means in the form of a socket part 74 extending from cover 73 for receiving one end of the connecting pipe therein. Cover 73 thereby extends at an angle towards socket part 74, which angle is included with an imaginary plane enclosed by the circumference 76 of the cover. In this example the angle is about 45°, but it typically varies between 30° and 60° so as to create more space internally for possible inspection or unblocking means when said means have to negotiate a bend from connecting pipe 3 to either one of the connecting pipe members 1. The cover is concave on all sides, as a result of which a sloping surface is created, which helps to dissipate settling forces and the like in an underground situation.

Also in this case a socket part including a flexible ring is used so as to provide a reliable connection without the use of a glue. Thus the invention can be implemented in existing situations in a very simple manner, as only the existing cover of the boundary piece 70 needs to be exchanged for the thus modified cover 73, from which the connecting pipe 3 will extend in that case to provide a connection with the access pit 2 that lies at the surface. Cover 73 forms a hermetic seal by means of clamps 73 and an intermediate gasket.

In this example sewer pipes 1, 3 and base part 70 of intermediate part 7 are all made of PVC, whilst cover 73 and at least an important part of the access pit 4 has been formed of polyethylene by injection moulding at a low pressure. Within the framework of the invention also other materials and manufacturing techniques are possible, however. Thus it is also possible to make all parts of PVC or of polyethylene or another material, whether or not by injection moulding at a low pressure. The use of flexible rings in the socket connections 22, 74 makes it possible to use different plastics, which after all need not be glued together.

Figure 3 shows the access pit 2 in more detail. A projection (not shown) on cover 21 engages in a recess formed in the cover seat for that purpose, thus locking the cover in the illustrated, closed position. Access to said projection can be gained by means of a simple key 8, by means of which said projection can be pushed aside so as to release the cover. In practice this arrangement appears to provide adequate protection in most cases against entry into the pipe system.

The access pit comprises a flanged edge 23 at the surface, an edge 24 of which extends practically vertically downwards. With this edge 24 the unit engages behind an upwardly extending part of a wall plate, which is in turn mounted on front wall 6. A projection 51 extending from wall plate 5 is thereby received in a practically complementary opening 25 in the flanged edge so as to centre the unit and fix it in position in lateral direction as well.

Figure 4 is a cutaway view of the access pit that is shown in cross-sectional view in Figure 5. Access pit 2 comprises a chamber 26, which is open on a bottom side so as to enter into open communication with the connecting pipe 3 that extends into this part of the access pit 2. For easy reference the mutual seal by means of a flexible ring is not shown in this figure. A gasket 91 between the two parts provides an adequate seal, whilst a second gasket 92 forms a seal between cover 21 and its interior part 9 on the one hand and an upper edge of chamber 26 on the other hand.

The interior part 9 comprises a first space, which is in open communication with the chamber 26 of the access pit 2, and thus with the pipe system 1, 3, via a channel extending outside the plane of the cross-section of Figure 5. Interior part 9 furthermore comprises a second space 94, which is in open communication with the outside air via a chink 27 between cover 2 and the cover seat. A valve

95 is present between the two spaces 93, 94, which valve provides an airtight seal between the two spaces. Valve 95 bears on its seat under the influence of gravity. In those cases where access pit 2 is not used vertically, it is possible, in a manner which is known per se, to use an embodiment wherein the valve 95 is held down onto its seat

96 by means of spring pressure. If a sub-atmospheric pressure occurs in pipe system 1, 3, this sub-atmospheric pressure will also prevail in first chamber 93. Valve 95 will be lifted from its seat 96 under the influence thereof, and an open communication with the outside air will be created, as a result of which the sub- atmospheric pressure will be eliminated. Thus the access pit not only provides access to the pipe system, but it also functions as a stack vent.

A second embodiment of access means according to the invention is shown in Figures 6 and 7. The figures show a house connection of a sewer system wherein the underground part of the pipe system 1 that is located outside the house, on the right-hand side in Figure 6, is present at a significantly lower level than the part of the system that is located inside the house, which is shown on the left- hand side in Figure 6. For this situation the invention provides a bend 80, which on the one hand connects practically horizontally to the part of the pipe system that is located inside the house and which on the other hand provides a connection to the part of the pipe system that is located outside the house via a bend 81. Also in this case the access means for the pipe system comprise an access pit 2 including a chamber 26, which is connected to bend 80 via a connecting pipe 3. The access pipe thereby extends practically vertically from bend 80.

Bend 80 is shown in more detail in cross-sectional view in Figure 7. The figure shows that bend 80 has an internal shoulder 82, which extends into bend 83 on the side facing away from connecting pipe 3. Said shoulder 82 provides a perceptible stop when access to the pipe system is being gained with unblocking means, for example, via access pit 2. The moment the presence of said stop is perceived, the operator will know that the end of the unblocking means is positioned in front of the entrance of the part of the pipe system that is present inside the house. In that position an attempt can be made to enter the part of the pipe system that is present inside the house.

Beyond shoulder 82, bend 80 has a downwardly sloping flank 84, which supports the passage through bend 83 of the waste material to be transported through the pipe system. Thus bend 84 will get clogged less easily. If desired, an expansion sleeve can be used under bend 80, which allows axial expansion and compression in vertical direction so as to absorb any forces being exerted on the pipe system. For the rest the access means of this second embodiment are comparable if not identical to those of the first embodiment, to which reference is therefore made for a more detailed description.

Although the invention has been described in more detail in the above only on the basis of these two exemplary embodiments, it will be understood that the invention is by no means limited to the examples described herein. On the contrary, numerous additional embodiments and forms can be realised by a person skilled in the art without departing from the scope of the invention. Thus it is possible within the scope of the invention to use other materials, and the invention is not only suitable for sewer systems but for all pipe systems that lie some distance below a surface, but which nevertheless need to be accessible. It is furthermore possible to use an access pit having an interior that comprises more or different parts, if desired, and in addition to that it is possible to use access pits that do not comprise an interior part. In the first embodiment described herein an intermediate part is used that is highly compatible with intermediate parts in existing systems, the so-called boundary pieces. Within the scope of the invention it is also possible, however, to use an intermediate part which has been specifically manufactured for that purpose, and which is not interchangeable at least in part with an existing boundary piece. All in all, with the access means the invention opens an entirely new avenue in the field of pipe systems.

Claims

1. Access means for a pipe system that is separated from a surface, comprising an access pit, in which a chamber is present which is open on a first side of the access pit so as to enter into open communication with the pipe system, and which includes a reclosable cover on a second side, which is intended to be positioned at least near the surface and which provides access to the pipe system via said chamber in its open position.

2. Access means according to claim 1, characterized in that the access pit, on a first side thereof, includes at least a part of connecting means for realising an at least substantially fluid-tight connection to a connecting pipe of the pipe system.

3. Access means according to claim 2, characterized in that said connecting means comprise a spigot part and a socket part being at least substantially complementary thereto, one part being formed on the first side of the access pit and the other part being present at one end of the connecting pipe.

4. Access means according to claim 3, characterized in that the spigot part and the socket part fit together with the interposition of a flexible ring so as to allow fluid-tight movement in axial direction of the parts relative to each other.

5. Access means according to any one of the preceding claims, characterized in that the cover includes an interior part comprising a first space, which is in open communication with the chamber, and a second space, which is in open communication with the outside air, and in that the two spaces are separated from each other by a valve which bears on a valve seat in an at least substantially fluid-tight manner so as to shut off the first space, but which is lifted from the valve seat under the influence of an under-pressure in the first space in comparison with the second space so as to open a fluid connection between the first space and the second space.

6. Access means according to any one of the preceding claims, characterized in that said cover can be locked in position.

7. Access means according to any one of the preceding claims, characterized in that the chamber is connected to the pipe system through the interposition of a connecting pipe, and in that the connecting pipe extends from a cover of an intermediate part that is incorporated in the pipe system.

8. Access means according to claim 7, characterized in that the cover extends at an angle with respect to a plane that is enclosed by a circumference thereof in the direction of the connecting pipe extending therefrom.

9. Access means according to claim 8, characterized in that the angle of the cover varies between 30° and 60°.

10. Access means according to claim 7, 8 or 9, characterized in that the cover includes at least a part of connecting means for realising an at least substantially fluid-tight connection to a connecting pipe.

11. Access means according to any one of the claims 1 - 6, characterized in that the chamber is connected to the pipe system through the interposition of a connecting pipe, and in that said connecting pipe extends from a pipe bend that is incorporated in the pipe system.

12. Access means according to claim 11, characterized in that the bend comprises an internal shoulder, which extends into the bend on a side facing away from the connecting pipe.

13. Access means according to any one of the preceding claims, characterized in that the chamber includes at least a part of fixation means for attachment to a wall plate.

14. Access means according to claim 13, characterized in that a flanged edge is present on an upper side of a wall of the chamber, and in that said fixation means comprise an edge extending downwards from said flanged edge, which edge is capable of engaging behind a part of the wall plate.

15. Access means according to claim 13 or 14, characterized in that said fixation means comprise a snap member which is capable of effecting a snap connection between the chamber and the wall plate when said chamber is placed against said wall plate.

16. An intermediate part as used in the access means according to any one or more of the claims 7 - 10.

17. A bend intended for use in the access means according to claim 11 or 12.