EP3156727A1

EP3156727A1 - Pipe system, coupling piece and method for installing the pipe system in a shaft of a building

Info

Publication number: EP3156727A1
Application number: EP16194231.3A
Authority: EP
Inventors: Martijn Anne Johan Lambert AARTS; Rico Theodoor Jozef SCHIJNS
Original assignee: Cox Geelen Bv
Current assignee: Cox Geelen Bv
Priority date: 2015-10-16
Filing date: 2016-10-17
Publication date: 2017-04-19
Anticipated expiration: 2036-10-17
Also published as: NL1041532B1; EP3156727B1

Abstract

Pipe system for use as ventilation or flue gas discharge channel, comprising at least a first and second pipe segment (35, 36) and at least a first and second tubular coupling piece (39, 40) configured to couple the pipe segments (35, 36) to each other via a coupling piece (39). One of the coupling pieces (39, 40) or the pipe segments (35, 36) is provided with at least one external attaching element (50) configured for the purpose, when pipe segments (35, 36) and coupling pieces (38, 40) are coupled, of attaching at least one elongate connecting element (45, 46) adjustably in length direction thereto. Also provided is a method for installing the pipe system in a shaft, such as a ventilation or flue gas discharge shaft of a building, and a coupling piece (39), pipe segment and ring element provided with attaching means (50) for attaching the connecting element (45, 46).

Description

The invention relates to a length-adjustable pipe system, particularly for use as ventilation and/or flue gas discharge channel. The invention also relates to a coupling piece configured for use in such a pipe system, an assembly of a coupling piece and pipe segment and a method for installing the pipe system in a shaft of a building, such as a ventilation or flue gas discharge shaft.
Separate or combined ventilation and flue gas discharge channels are installed in practice for ventilation purposes, such as for instance for supplying and/or discharging fresh air to and/or from a space, for discharging flue gases from heating devices or other combustion devices such as ovens, and for instance for supplying combustion air thereto.
Such ventilation and flue gas discharge channels are constructed nowadays from plastic or metal tubes or pipes, such as tubes or pipes of polypropylene, aluminium or stainless steel. The pipe material to be selected depends here on, among other factors, the type of combustion device, i.e. the type of combustion material such as gas, oil or wood, the final temperature of the flue gas to be discharged, which in higher efficiency devices will be lower than in the case of lower efficiency devices, and the degree of condensation in the pipe system.
Particularly in older buildings these ventilation and flue gas discharge channels may still consist of brickwork or concrete or other stone or ceramic shafts or chimneys, or ventilation or flue gas discharge shafts assembled from galvanized pipes. Because of, among other reasons, condensation on the pipe wall due to, among other factors, water vapour in the flue gas or in the air to be discharged from shower areas or bathrooms or other moist spaces, these galvanized pipes are highly susceptible to corrosion, whereby leakages occur in the pipe system after a period of time. In the case of a flue gas discharge system such leakages can result in potentially dangerous situations, since components present in the flue gas, such as nitrogen dioxide, carbon dioxide, carbon monoxide and sulphur dioxide, can be released in the building instead of being discharged to the outside via for instance a discharge or chimney flue on the roof of the building.
Replacement of such a pipe system in practice often involves cutting and breaking work in the building, this not only being undesirable from a cost viewpoint but also causing considerable inconvenience to the residents.
Also in the case an older combustion device is replaced by a more modern appliance it may be necessary, for instance on the basis of the composition and temperature of the flue gas to be discharged, to replace the existing flue gas discharge system by a pipe system constructed from materials better suited to the purpose. Such modern combustion devices have a relatively low flue gas temperature compared to older devices, although this is associated with a greater degree of condensation in the pipe system. The lower flue gas temperature does on the other hand make it possible however to construct the flue gas discharge system wholly from a plastic material.
Owing to the wide variety of height dimensions of the spaces in a building and the wide variation in the position of a ventilation inlet or outlet and the position of the flue gas outlet of heating devices and the like, the installation of new pipe systems and/or the renovation of existing ones, such as for use as ventilation or flue gas discharge channel, is usually time-consuming and therefore costly custom work.
US patent application 228,883 discloses a pipe system for flue gas discharge wherein two mutually coupled pipe segments can be connected adjustably in length direction to each other via an elongate connecting strip. Because the pipe segments are attached to each other in direct contact, a relatively large movement occurs in longitudinal direction during expansion and contraction of the pipe segments, particularly in the case of a cascade of coupled pipe segments, whereby branch pipes of combustion devices or the like connected to the pipe segments must also be suitable to follow such a movement.
The invention therefore has for its object to provide a pipe system which can be installed as ventilation or flue gas discharge channel, particularly a pipe system suitable for replacing an existing ventilation or flue gas discharge channel in a building easily and quickly without unnecessary cutting or breaking work, and wherein the movement in longitudinal direction during expansion and contraction thereof is effectively overcome.
This object is achieved in a first aspect of the invention with a pipe system for use as ventilation or flue gas discharge channel, comprising at least a first and second pipe segment and at least one elongate connecting element configured to couple the pipe segments movably in length direction to each other, characterized in that the pipe system comprises at least a first and second tubular coupling piece configured to couple the pipe segments via a coupling piece to each other, wherein one of the coupling pieces or the pipe segments is provided with at least one external attaching element configured for the purpose, when pipe segments and coupling pieces are coupled, of attaching the at least one elongate connecting element adjustably in length direction thereto.
A coupling piece can be positioned fixedly in a space in a building at substantially any desired position or height by means of the elongate connecting element. Together with the feature that the pipe segment and the coupling piece connect movably in length direction to each other, a very simple and dimensionally flexible mounting is obtained. That is, custom work can be provided in a simple manner with pipe segments and coupling pieces of predetermined lengths.
Because the pipe segment and the coupling piece are connected for relative movement in length direction to each other, the pipe segment can expand freely in longitudinal direction under the influence of the temperature of, for instance, flue gas flowing therethrough, and of course also contract again, without the fixed position of the coupling piece in the space thereby changing. It will be understood that the relatively movable connection of a pipe segment and coupling piece takes a gas-tight and liquid-tight form, for instance by means of a per se known sealing ring arranged along the inner periphery of the coupling piece and/or along the outer periphery of a pipe segment.
The flue gas outlet of a heating device can be connected directly or branched to the coupling piece without having to make provisions for offsetting or eliminating forces acting on this connection as a result of expansion or contraction of the pipe system.
Although the outlet from or inlet to a device can be connected to the end of the coupling piece not connected to a pipe segment, according to an embodiment of the invention, the at least one coupling piece is provided between a first and second end thereof with at least one connecting opening for connection thereto of a branch pipe part. The branch pipe part then leads to an appliance to be connected to the pipe system.
In an embodiment of the invention the at least one attaching element is a fixed part of a pipe segment, a coupling piece and/or a ring element, such as a clamping ring, attachable to a pipe segment or coupling piece. Provided particularly are a number of attaching elements arranged distributed along the periphery of a pipe segment, a coupling piece or ring element thereof.
Although a pipe segment or a coupling piece or an annular element of the pipe system according to the invention can in principle be provided with one attaching element, it is advantageous for the purpose of facilitating mounting of the pipe system to provide the at least one coupling piece with a number of protruding attaching elements arranged distributed along the periphery thereof, that is with a plurality of attaching elements distributed in tangential direction on the outer periphery of a pipe segment, coupling piece or ring element and/or with a plurality of attaching elements distributed in longitudinal direction on the outer periphery of a pipe segment, coupling piece or ring element.
Particularly for installation of the pipe system in a building consisting of multiple storeys, such as an apartment complex, wherein a device must be connected to the pipe system on one or more of the floor levels, according to the invention the at least one attaching element is configured for attachment thereto of a further elongate connecting element for adjustably attaching a further pipe segment or coupling piece of the pipe system to this further elongate connecting element in length direction thereof.
In such a cascade of mutually coupled coupling pieces a coupling piece to which a branch pipe part can be connected is then placed at each position where a connecting opening for a device to the pipe system is desired. The different coupling pieces are fixed in their relative position by means of the respective elongate connecting elements. Even in the case of a ventilation or flue gas discharge channel constructed in this manner and covering multiple storeys of for instance a high apartment building the individual connecting openings remain in their position because the expansion forces acting on the pipe system are offset in that the coupling pieces and pipe segments are connected for relative movement to each other.
It will be understood that the different pipe segments of a pipe system can be of differing length. When use is made of pipe segments of standard lengths, for instance corresponding to the average height of a space, a greater height or for instance a whole storey of a building can be easily spanned by mutually coupling pipe segments using a coupling piece without connecting opening for a branch pipe part or a coupling piece with a closable connecting opening.
The connecting element can take different forms, such as a chain, a wire or cable, a strip, a threaded end with adjusting nuts such as for instance wing nuts, etc., wherein the attaching elements have a form adapted hereto, such as for instance the form of a hook, eye or plate.
In an embodiment of the pipe system according to the invention the at least one elongate connecting element and the at least one attaching element can be connected to each other via a pin/hole connection. The at least one elongate connecting element is particularly provided with holes arranged distributed in longitudinal direction thereof, wherein the at least one attaching element is eye-like or eye-shaped for the purpose of attaching the connecting element via a pin-hole-eye connection to the attaching element.
In addition to the fact that such an attachment can be realized quickly and easily in practice, even under difficult assembly conditions, such as on a roof of a building, the distance between two successive mutually attached coupling pieces can also be easily adjusted by selecting a suitable attaching hole in longitudinal direction of the connecting element.
In a further embodiment of the invention the at least one elongate connecting element is strip-like or strip-shaped, for instance of stainless steel, and the at least one attaching element defines a strip-like receiving slot extending in longitudinal direction of a pipe segment or coupling piece for receiving the strip-like connecting element movably therein, with an eye formed transversely of the strip-like receiving slot for connecting the connecting element to the attaching element via the pin-hole-eye connection.
The strip-shaped receiving slot of the attaching element facilitates the attachment thereof to the strip-shaped connecting element because with a suitable dimensioning, once received in the receiving slot, the eye of the attaching element and a hole of the connecting element can be easily aligned via a movement of the pipe segment, the coupling piece and/or the connecting element in longitudinal direction.
In order to prevent bending or buckling of a connecting element in longitudinal direction thereof, whereby the mutual distance between the coupled pipe segments and coupling pieces could change, in an embodiment according to the invention the at least one elongate strip-like connecting element has a substantially T-shaped or U-shaped cross-section. That is, wherein the crosspiece or leg of the T-shape or the crosspieces or legs of the U-shape can be relatively narrow and extend substantially on the side edge of the main stem in which the holes are formed.
In order to further facilitate the mounting of the connecting elements and coupling pieces the coupling piece is provided near each end with at least one attaching element.
The connection of the tubular coupling piece and a pipe segment can be realized, among other ways, such that either the pipe segment fits slidably in an open end of the coupling piece or the pipe segment fits slidably over an open end of the coupling piece. In such a further embodiment according to the invention the at least one coupling piece is provided with at least one blocking element for coupling a coupling piece and pipe segment movably to each other over a limited distance in longitudinal direction.
When for connection thereof to each other the at least one coupling piece and the at least one pipe segment are configured to receive the pipe segment fitting movably in the coupling piece from an end thereof, the blocking element of the coupling piece can advantageously be formed as at least one stop for the at least one pipe segment formed internally of the coupling piece at a distance from the respective end. In the other case an external stop will suffice along the outer periphery of the coupling piece.
In particular for a pipe system wherein during use a high degree of condensation can occur along the inner wall of the pipe segments and the coupling pieces, for connection thereof to each other according to the invention the at least one coupling piece and the at least one pipe segment are configured to receive the pipe segment fitting movably in the coupling piece from a first end thereof and to receive a second end of the coupling piece fittingly in a further pipe segment.
In the installed situation, the pipe system is then built up in each case such that the first end of the coupling piece is located higher than the second end of the coupling piece.
In order to facilitate installation of the pipe system still further, according to an embodiment of the invention, the connecting elements each have the same length with at least one attachment point located at a first end thereof for attachment of a coupling piece to an attaching element and with further attachment points arranged relative to each other over a distance from a second end thereof, or from a marking located close to the second end on the connecting element, wherein the at least one attaching element and the at least one connecting opening for each coupling piece have a fixed distance and wherein a graduation scale is arranged externally on the coupling piece which extends in longitudinal direction from the attaching element to the at least one connecting opening, wherein the graduation scale is provided with a measurement indicator such that, when two coupling pieces are connected to each other in longitudinal direction by a connecting element, the longitudinal centre-to-centre distance between the connecting openings of the connected coupling pieces corresponds to this measurement indicator on the coupling piece adjacent to the second end or to the marking on the connecting element.
The relative distance between two adjacent coupling pieces of the pipe system can now be easily adjusted by having the connecting element to end at, or having a marking on the connecting element to end at, this measurement indicator on the coupling piece, such as a measurement mark, corresponding to the desired distance between the connecting openings of the coupling pieces. This is particularly advantageous when the pipe system is installed from an outlet end in an existing ventilation or flue gas discharge shaft of a building.
In a second aspect the invention therefore provides a method for installing a pipe system according to the first aspect of the invention in a substantially vertical shaft, such as a ventilation or flue gas discharge shaft of a building, wherein the pipe system is inserted into the shaft from an end thereof open to the outside, the method comprising:

attaching a pipe segment or coupling piece with its at least one attaching element to an elongate connecting element,
connecting the coupling piece and a pipe segment to each other,
arranging the pipe segment or coupling piece in the shaft and lowering the coupling piece with the pipe segment connected thereto into the shaft, wherein the connecting element serves as support for further lowering of the pipe system into the shaft, and
supporting the connecting element such that an end of the pipe segment and the connecting element remains at a distance outside the open end of the shaft.

It will be understood that the first two steps may also be reversed. This is then particularly the case when operation takes place with an assembly of a fixedly connected coupling piece and pipe segment.
For installation in a shaft from the outlet end of a pipe system assembled from parts, i.e. from a cascade of coupling pieces and pipe segments, the method according to the invention further provides for:

connecting a further coupling piece to the end of the pipe segment located outside the shaft,
connecting a further pipe segment to the further coupling piece,
attaching the further coupling piece with its at least one attaching element to the end of the connecting element located outside the shaft,
attaching a further connecting element to the at least one attaching element of the further pipe segment or further coupling piece,
lowering the coupled pipe system into the shaft, wherein the further connecting element serves as support as the coupled pipe system is lowered further into the shaft, and
supporting the further connecting element such that an end of the further pipe segment and the further connecting element remains at a distance outside the open end of the shaft.

It is also the case here that, when work takes place with assemblies of a fixedly connected coupling piece and pipe segment, the first step is to arrange in a coupling piece of an assembly the pipe segment of a subsequent assembly, etc.
The pipe system is then assembled successively in parts or sections and introduced part by part into the ventilation or flue gas discharge shaft from the outlet end.
Further provided for in the method according to the invention is that the end of the connecting element located outside the shaft is attached to support means engaging on the shaft for supporting the pipe system freely suspended, preferably freely suspended in two degrees of freedom, in the shaft.
Such a freely suspended assembly has the advantage that the pipe system is not in mechanical contact with the inner wall of the shaft, whereby transmission of sound and heat from the pipe system to the wall of the shaft is effectively avoided, also in shafts which do not run entirely vertically. The pipe system will, as a result of the freely suspended assembly, also take up a position which is as vertical as possible.
During installation in a shaft of a building consisting of multiple storeys wherein a device must be connected to the pipe system on each storey or on a number of the storeys, so wherein an opening debouching into the shaft is provided on one or more storeys for connection of a branch pipe part to the shaft, according to the method of the invention the pipe system is installed by, starting from a lowest storey, attaching successive coupling pieces with pipe segments at a mutual distance to the successive connecting elements such that, when a pipe system has been installed, at the position where a branch pipe part has to be arranged the connecting opening of a respective coupling piece is located opposite a respective opening debouching into the shaft.
It is advantageous here to use pipe segments and coupling pieces of a length such that using a single intermediate pipe segment the coupling pieces of two adjacent storeys, i.e. the connecting openings thereof, are mounted at the desired height for connection of a device. The pipe system is then assembled and installed such that a connecting opening of a coupling piece of the pipe system is located opposite each opening debouching into the shaft.
By making use of coupling pieces with a closable connecting opening it is also possible, in anticipation of a future connection, to position coupling pieces where a future connection is planned or desired.
For a stable connection of coupling pieces and pipe segments, according to the method of the invention, each further coupling piece is connected fixedly to the end of the pipe segment located outside the shaft. This connection can for instance be made by means of for instance self-tapping screws.
In a third aspect the invention provides a coupling piece, a pipe segment and/or a ring element provided with at least one attaching element as described in the foregoing, and an assembly of a coupling piece and a pipe segment fixedly connected to each other, particularly wherein the pipe segment and the coupling piece are welded together, configured for use in a pipe system as described in the foregoing.
The invention is now elucidated by way of example in more detail with reference to the accompanying figures. The invention is by no means limited to the embodiment of the invention shown in the figures. The same or similar elements also have the same reference numerals in the figures.

Figure 1 shows schematically and in partial cross-section a prior art flue gas discharge shaft of a building consisting of multiple storeys.
Figure 2 shows schematically and in partial cross-section a pipe system according to an embodiment of the invention installed in a flue gas discharge shaft of a building consisting of multiple storeys.
Figure 3 shows schematically and on enlarged scale a mounted coupling piece and pipe segments of the pipe system according to the embodiment of the invention as shown in figure 2.
Figure 4 shows schematically a longitudinal section through the coupling piece and pipe segments shown in figure 3.
Figure 5 shows schematically and on enlarged scale a mounted coupling piece having connected thereto a branch pipe part and pipe segments of the pipe system according to the embodiment of the invention as shown in figure 2.
Figure 6 shows schematically and on enlarged scale a mounted coupling piece with two branch pipe parts connected thereto and pipe segments of the pipe system according to the embodiment of the invention as shown in figure 2.
Figure 7 shows schematically an embodiment of a freely suspended attachment of the pipe system as shown in figure 2 installed in the flue gas discharge shaft.
Figures 8A, B illustrate schematically the attachment of a coupling piece and connecting element of two pipe systems according to the invention to an outlet opening located at different height.
Figure 9 shows schematically a mounted coupling piece and pipe segments of the pipe system provided with attaching elements according to an embodiment of the invention.

Shown schematically in figure 1 is a flue gas discharge system 10 of a building consisting of multiple storeys 11, 12. Located on the ground floor 11 are two combustion devices 17, 18, such as a central heating boiler and/or a hot water appliance, the flue gas outlet of each of which is connected via a branch pipe part 20, 21 to a flue gas discharge shaft 14. The flue gas discharge shaft 14 ends at an end 15 open to the outside air on the roof 13 of the building. Situated on the first floor 12 of the building in the shown embodiment is a single combustion device 16 likewise connected via a branch pipe part 19 to the flue gas discharge shaft 14.
Particularly in older buildings such a flue gas discharge shaft 14 still often consists of brickwork or other ceramic stone or shafts of concrete having arranged therein a galvanized pipe to which for instance likewise galvanized branch pipe parts 19, 20, 21 connect. As already described in the preamble, such galvanic pipes are highly susceptible to corrosion, whereby undesirable leakages occur in the pipes after a period of time. Particularly the replacement of a pipe extending in the flue gas discharge shaft 14 can in practice often involve cutting and breaking work which causes much inconvenience in the building. Also in the case of a flue gas discharge system constructed from plastic pipe it may also be necessary when replacing one or more older combustion devices 16, 17, 18, because of the composition and temperature of the flue gas to be discharged, to replace the existing plastic flue gas discharge system with a pipe system constructed from better suited materials.
Although the combustion devices 16, 17, 18 are all shown mounted at the same height, it should be understood that these devices and their branches 19, 20, 21 to the flue gas discharge shaft 14 on the various floor levels 11, 12 can be located at different heights. The installation of a new flue gas discharge pipe system then requires custom work, is time-consuming and thereby rather costly.
Figure 2 shows a pipe system 30 according to an embodiment of the invention which is arranged in the existing flue gas discharge shaft 14 and, in the shown example and as seen in the direction from the ground floor 11 to the roof 13, comprises a first cylindrical pipe segment 35, a second cylindrical pipe segment 36 and a third cylindrical pipe segment 37 which have connecting thereto in each case a first cylindrical coupling piece 38, a second cylindrical coupling piece 39 and a third cylindrical coupling piece 40 located at a distance from each other in longitudinal direction in the flue gas discharge shaft 14. The first pipe segment 35 is received fitting with an end in the first coupling piece 38 and received fitting with another end in the second coupling piece 39. The second pipe segment 36 is received fitting with an end in the second coupling piece 39 and received fitting with another end in the third coupling piece 40. The third pipe segment 37 is received fitting in an end of the third coupling piece and the other end of the third pipe segment 37 ends on the roof 13 of the building in an end 31 of the pipe system 30 which is open to the outside air.
A first elongate connecting element 45 extends between the first and second coupling piece 38, 39 in longitudinal direction of the first pipe segment 35. A second elongate connecting element 46 extends between the second and third coupling piece 39, 40 in longitudinal direction of the second pipe segment 35. A third elongate connecting element 47 extends in longitudinal direction of the third pipe segment 37 from the third coupling piece 40 in the direction of the roof 13. The coupling pieces 38, 39, 40 are attached near the ends to the respective connecting elements 45, 46, 47 and the connecting element 47 is attached to the roof 13 of the building with the end not connected to the third coupling piece 40.
The third coupling piece 40 is in this way suspended fixedly from the roof 13 via the third connecting element 47, the second coupling piece 39 is suspended fixedly from the third coupling piece 40 via the second connecting element 46 and the first coupling piece 38 is suspended fixedly from the second coupling piece 39 via the first connecting element 45. The pipe system 30 thus consists here of a cascade of pipe segments 35, 36, 37 and coupling pieces 38, 39, 40 suspended in the flue gas discharge shaft 14.
Because the coupling pieces 38, 39, 40 are coupled to each other via the connecting elements 45, 46, 47, the pipe segments 35, 36, 37 can engage in freely movable manner or with sliding fit in longitudinal direction in a respective coupling piece. Each pipe segment 35, 36, 37 can hereby expand unobstructed in length direction under the influence of the temperature of for instance flue gas flowing therethrough. As a result of the connecting elements 45, 46, 47 the position of the coupling pieces 38, 39, 40 does not change as seen in length direction of the pipe system 30, or not significantly so, during expansion thereof. The flue gas outlet of a combustion device can therefore be directly connected or branched to a coupling piece 38, 40 without having to make provision to offset or eliminate forces acting on this connection as a result of expansion or contraction of the pipe system 30.
The pipe segments 35, 36, 37 and coupling pieces 38, 39, 40 are connected movably to each other in mutually gas and liquid-tight manner, for instance by means of a per se known sealing ring arranged along the inner periphery of a coupling piece 38, 39, 40 at the ends thereof and/or a sealing ring arranged along the outer periphery of a pipe segment 35, 36, 37 or another type of sealing means known in practice for this purpose. In the situation as shown in figure 2, the newly placed combustion devices 32, 33, 34 are therefore each connected directly via a branch pipe part 41, 42, 43 to a connecting opening of a respective coupling piece 38, 40 of the pipe system 30. The second coupling piece 39 of the pipe system 30 connects the first pipe segment 35 and the second pipe segment 36, and in the shown situation a branch pipe part is not connected to this second coupling piece 39.
Even in the case of a ventilation or flue gas discharge channel constructed in this manner in a for instance high apartment building which, other than as shown in figure 2, has more than two storeys, the individual connecting openings of the coupling pieces remain in their position because the expansion forces acting on the pipe system are offset in that the pipe segments can move freely in longitudinal direction.
Figure 3 shows an enlarged scale the second coupling piece 39 shown in figure 2 received in the flue gas discharge shaft 14 with the first pipe segment 35 connecting thereto at a first end 48 and the second pipe segment 36 connecting thereto at a second end 49 of the coupling piece 39. For attachment thereof to an elongate connecting element 45, 46 the coupling piece 39 is provided in the shown embodiment near each end 48, 49 with attaching elements 50 arranged distributed around the periphery of the coupling piece 39. The attaching elements 50 have a strip-shaped receiving slot 51 extending in longitudinal direction of the coupling piece 39 for receiving movably therein a strip-shaped connecting element 45, 46. An eye-shaped opening 52 is formed transversely of the strip-shaped receiving slot 51.
The strip-shaped connecting elements 45, 46 are provided with holes or openings 53, 54 placed spaced-apart over a distance in longitudinal direction thereof. By placing a strip-shaped connecting element 45, 46 in the strip-shaped receiving slot 51 of the attaching element 50 the coupling piece 39 can be attached easily to the connecting element 45, 46 by aligning a hole 53 of the connecting element with the eye-shaped opening 52 of the attaching element 50 and subsequently arranging a pin or pin-like body 55 through the eye-shaped opening 52 and the respective hole 53. The coupling piece is then attached to the connecting element via the thus formed pin-hole- eye connecting point 52, 53, 55.
In addition to the fact that such an attachment can be realized quickly and easily in practice, even under difficult assembly conditions, such as on a roof 13 of a building, the distance between two successive coupling pieces to be mutually attached can also be easily adjusted by selecting a suitable respective hole 53 of a connecting element 45, 46.
The strip-shaped receiving slot 51 of the attaching element 50 of the coupling piece 39 facilitates the attachment thereof to a strip-shaped connecting element 45, 46 because with a suitable dimensioning, once received in the receiving slot 51, the eye-shaped opening 52 of the attaching element 50 and a hole 53 of the connecting element 45, 46 can be easily aligned via movement of either the coupling piece 39 and/or the connecting element 45, 46 in longitudinal direction.
Although the coupling piece of the pipe system according to the invention can in principle be provided with one attaching element 50 to which both a first and second connecting element can be attached, it is advantageous for the purpose of facilitating mounting of the pipe system to provide a coupling piece with a number of protruding attaching elements 50 arranged distributed along the periphery thereof, that is, with a plurality of attaching elements, for instance four, distributed in tangential direction on the outer periphery of the coupling piece and/or if with a plurality of attaching elements distributed in longitudinal direction on the outer periphery of the coupling piece, such as for instance the attaching elements 50 close to each end 48, 49 of the coupling piece 39, this facilitating mounting of the connecting elements 45, 46, 47 and coupling pieces 37, 38, 39.
It will be appreciated that the attaching elements 50 can also be formed other than with a strip-shaped receiving slot 51 and eye-shaped opening 52 as shown. The attaching elements of a coupling piece can for instance be hook or pin-shaped, which hook or pin then engages in a hole 53, 54 of a connecting element 45, 46, 47. The connecting element can of course be provided with a number of hook-shaped elements spaced apart in length direction which engage on an attaching element of the coupling piece embodied as pin or the like. Bolt connections or screw eye connections or the like can also be applied. Instead of being strip-shaped, a connecting element can for instance also be formed by a chain, wire, cable, threaded end with adjusting nuts such as wing nuts or the like, wherein the attaching elements can then take the form of an eye, hook or for instance plate for engagement with a respective connecting element.
Figure 4 shows a longitudinal section through the coupling piece 39 and the pipe segments 35, 36 shown in figure 3. It can be clearly seen from figure 4 that from the second end 49 of the coupling piece 39 the second pipe segment 36 is received in freely movable manner therein. The first pipe segment 35 can also be received at the first end 48 of the coupling piece 39 for free movement in longitudinal direction therein.
For a stable connection of coupling pieces 38, 39, 40 and pipe segments 35, 36, 37 the end of a pipe segment 35, 36, 37 received in each case in the first end 48 of a coupling piece 37, 38, 39 can be connected fixedly to the respective coupling piece. This connection can for instance be made by means of self-tapping screws as indicated schematically with the reference numeral 57 in figure 3, but is preferably made by means of a thermal weld connection.
In order to prevent the possibility of a pipe segment falling through a coupling piece, which can for instance occur during assembly from the roof 13, the coupling piece 39 is provided with one or more bounding or blocking elements in the form of a stop 56 protruding internally in radial direction. This effectively prevents a pipe segment 35, 36 passing through a coupling piece 39. The length of a coupling piece and the placing of the stop 56 therein are selected such that a pipe segment can move freely over a sufficient distance in the coupling piece in order to offset expansion of the pipe segment.
The stop 56 can also be located higher in the coupling piece 39 as seen in the plane of the drawing, i.e. shifted in the direction toward the second end 49, above the connecting openings 60, 61.
Figure 5 shows on enlarged scale the third coupling piece 40 shown in figure 2 received in the flue gas discharge shaft 14 and with the second pipe segment 36 connecting thereto at a first end 48 and the third pipe segment 37 connecting thereto at a second end 49 of the coupling piece 40. The flue gas outlet of the combustion device 32 is connected to the coupling piece 40 via a branch pipe part 41. The branch pipe part 41 engages here in a connecting opening 60 of the coupling piece. The opposite connecting opening 61 of the coupling piece is closed by means of a cover 62. The branch pipe part 41 runs through a shaft opening 22 which is closed all-around by means of a collar 63 of plastic or rubber or the like.
Figure 6 shows on an enlarged scale the first coupling piece 38 shown in figure 2 received in the flue gas discharge shaft 14 and with the first pipe segment 35 connecting thereto at a second end 49. A pipe segment is not connected to the first end 48 of the coupling piece 38. This end can be left open or closed, for instance by a closed bottom formed in the coupling piece. When the end 48 of the coupling piece 38 is open, condensation can drain out of the pipe system 30 via the open end 48. The flue gas outlet of the combustion device 34 is connected via a branch pipe part 43 to the coupling piece 38. The branch pipe part 43 engages here in the connecting opening 60 of the coupling piece. The combustion device 33 is connected via a branch pipe part 42 to the opposite connecting opening 61 of the coupling piece 40. The branch pipe part 42 runs through a shaft opening 24 and the branch pipe part 43 runs through a shaft opening 23, both of which openings 23, 24 are again closed all-around by means of a collar 36.
It will be appreciated that the different pipe segments 35, 36, 37 of a pipe system can be of differing length. It is however advantageous to use pipe segments 35, 36, 37 of standard lengths as far as possible, for instance corresponding to the average height of a space. Greater lengths, or heights, can then be easily spanned by mutually coupling pipe segments with a coupling piece without a connecting opening for a branch pipe part or a coupling piece with a closable connecting opening.
Provided in a preferred embodiment of the invention is an assembly of a respective coupling piece 39, 40 and a pipe segment 35, 36 fixedly connected thereto. The pipe segment 35, 36 is then preferably connected fixedly at the first end 48 to a respective coupling piece 39, 40.
It is also advantageous to make use as much as possible of identical coupling pieces 38, 39, 40 as shown in figures 2-6. Where a connection of a combustion device is not necessary a respective connecting opening 60, 61 of a coupling piece 38, 39, 40 can then be closed by means of a cover 62. Greater pipe lengths can be realized by lengthening pipe segments of standard length via a coupling piece with connecting openings 60, 61 which are all closed by means of a cover 62, as for instance the coupling piece 39 shown in figure 3.
A coupling piece can of course be provided with more than one or two connecting openings 60, 61 spaced-apart in tangential direction. The connecting openings 60, 61 can further also be distributed in length direction of a coupling piece, for instance a connecting opening 60 close to the first end 48 and another connecting opening 61 close to the second end 49 of a coupling piece 38, 39, 40.
By making use of coupling pieces with a closable connecting opening it is also possible, in anticipation of a future connection, to position coupling pieces where a future connection is planned or desired which is then closed for the time being by a cover.
Figure 7 shows schematically an embodiment of a freely suspended attachment of the pipe system 30 as shown in figure 2 installed in the flue gas discharge shaft 14. Two L-shaped mounting brackets 26 of for instance sheet steel are attached fixedly to the roof 13 on either side of the outlet end 25 of the flue gas discharge shaft 14. The upright side of a mounting bracket 26 is provided with an opening 27 through which passes a carrying bar 28 in toothed form at its ends. The distance between the teeth and the thickness of the mounting brackets 26 are adapted to each other such that in mounted situation the upright side of a mounting bracket 26 engages between two adjacent teeth of the carrying bar. The toothed ends of the carrying bar 28 connect to a cylindrical part 29 in the centre of the carrying bar 28 through which the pipe segment 37 extends.
The connecting element 47 is attached via a slot-shaped hole 54 thereof to the cylindrical part 29 of the carrying bar, for instance by means of a screw bolt or by a hook connection or a pin which engages in a respective hole 54. Because the coupling pieces 38, 39, 40 are mutually connected in each case via a respective connecting element 45, 46, 47, the whole pipe system 30 is in this way mounted freely suspended in the flue gas discharge shaft 14 via the support means 26-29. Via the toothed ends of the carrying bar 28 the pipe system 30 can swing to some extent in the flue gas discharge shaft 14, this being advantageous in the case of assembly in shafts which are not precisely vertical.
Because the cylindrical part 29 of the carrying bar 28 does not engage on the pipe segment 37, this pipe segment can expand freely. The free end of the pipe segment 37 and the support means 26-29 can be covered with a cap 31 as shown in figure 2. It will be appreciated that the support means 26-29 can be embodied other than as shown, for instance wherein an elongate carrying bar passes directly through the slot-shaped hole 54 of the connecting element 47.
In order to prevent bending or buckling of a strip-like elongate connecting element 45, 46, 47 manufactured from metal or plastic in longitudinal direction thereof, whereby the mutual distance between the coupled coupling pieces 38, 39, 40 could change, it is advantageous to use strip-like connecting elements of substantially T-shaped or U-shaped cross-section. That is, wherein the crosspiece or cross-leg of the T-shape or the crosspieces or cross-legs of the U-shape can be relatively narrow and extend for instance substantially on the side edge of the main stem of the attaching element in which the holes 53, 54 are formed. The connecting elements are preferably manufactured from stainless steel or another material which does not corrode easily.
A coupling piece 38, 39, 40 can be positioned fixedly in a space in a building at substantially any desired position or height by means of an elongate connecting element 45, 46, 47.
In order to facilitate installation of the pipe system still further, in an embodiment the connecting elements 45, 46, 47 each have the same length with at least one hole 54 at a first end 68 thereof and with holes 53 arranged preferably equidistantly over a distance from a second end 69 thereof or from a marking on the connecting element 45, 46, 47 located near the second end 69. The eye 52 of a respective attaching element 50 and a respective connecting opening 60, 61 have for each coupling piece 38, 39, 40 a fixed centre-to-centre distance in longitudinal direction of the coupling piece, wherein a graduation scale 65 is arranged externally on the coupling piece 38, 39, 40 as illustrated in figures 3, 5, 6.
On this the graduation scale 65, for instance in the form of measurement marks extending from the eye 52 of the attaching element 50 in longitudinal direction to the connecting opening 60, 61, the distance between two adjacent measurement marks or graduation scales is equal to or a multiple of a centre-to-centre distance between two adjacent holes 53 of a connecting element 45, 46,47.
The graduation scale 65 is also provided with a measurement indicator in numbers such that, when two coupling pieces 38, 39, 40 are connected to each other in longitudinal direction by a connecting element 45, 46, 47, the longitudinal distance from the centre of the connecting opening 60, 61 of the one coupling piece 40 and the centre of the connecting opening 60, 61 of the connected other coupling piece 39 corresponds to that measurement indicator on the coupling piece 39 associated with the graduation scale adjacent to the second end 69 of the connecting element 45, 46, 47.
The mutual distance between two adjacent coupling pieces 39, 40 of the pipe system can now be easily adjusted by having the connecting element 46 to end at, or having a marking on the connecting element 46 to end at, this measurement indicator on the coupling piece 39, such as a measurement mark, corresponding to the desired distance between the connecting openings 60, 61 of coupling pieces 39, 40 mutually connected via the connecting element 46. This is particularly advantageous when the pipe system 30 is installed from an outlet end 25 in an existing ventilation or flue gas discharge shaft 14 of a building.
Shown in figures 8A, B is a coupling piece 70, which corresponds in structure and form to a coupling piece 38, 39, 40, with a branch pipe part 71 connected to the connecting opening 61. The graduation scale 65 is dimensioned and arranged on the coupling piece 70 such that the centre 66, 67 of the first hole 53 on the second end 69 of a connecting element 72, 73 forms the marking for adjusting the longitudinal centre-to-centre length between the connecting openings 61 of two coupling pieces 70 mutually coupled via a connecting element 72, 73.
Figure 8A shows the situation wherein the pipe system is mounted in a building consisting of multiple storeys, with a storey height of 2.7 m. The centre 66 of the first hole 53 on the second end 69 of the connecting element 72 then lies opposite the measurement indicator 2.7 m.
Figure 8B shows the situation wherein the pipe system is mounted in a building consisting of multiple storeys, with a storey height of 2.9 m. The centre 67 of the first hole 53 on the second end 69 of the connecting element 72 then lies opposite the measurement indicator 2.9 m.
A range of storey heights to be spanned can be covered using standard lengths of the pipe segments, the coupling pieces and the connecting elements. It will be apparent that the storeys in a building need not all have the same height, provided they fall within the height range bounded on the upper side at which a pipe segment can still engage in a coupling piece and bounded on the underside at which the pipe segment lies against a stop or other bounding element in a coupling piece.
The modular construction of the invention makes it possible to construct a pipe system in a shaft from the end of the shaft open to the outside. Referring to figure 2, the first coupling piece 38 is then attached here first with its attaching element 50 to the first elongate connecting element 45 corresponding to the respective storey height. The first pipe segment 35 is then connected to the first coupling piece 38. The first coupling piece 38 with the first pipe segment 35 is then inserted from the outlet end 25 into the shaft 14 and, by lowering the first connecting element 45, the whole entity will descend a distance further into the shaft 14 until the first end 69 of the connecting element 45 just still protrudes outside the shaft 14.
When use is made of assemblies of a coupling piece and pipe segment, such as an assembly of a coupling piece 39 and pipe segment 35, the connecting element 45 can first be attached to the assembly and subsequently to the coupling piece 38 in which the pipe segment 35 is then already received.
The first end 69 of the first connecting element 45 protruding outside the shaft 14 is now attached to the attaching element 50 of the second coupling piece 39. The second elongate connecting element 46 is also attached to the second coupling piece 39, again in accordance with the desired mounting height of the connecting opening at a respective storey. The second pipe segment 36 is connected to the second coupling piece 38 and the whole entity is inserted further into the shaft 14, now with support of the second connecting element 46. That is, the whole entity moves further downward into the shaft 14.
This process continues until the final coupling piece 40 has been arranged in the shaft, after which the third elongate connecting element 47 is finally attached to the roof 13 by means of the support means 26-29.
The pipe system 30 is thus assembled in successive parts or sections and inserted part by part into the shaft 14 from the outlet end 25 such that opposite each opening 22, 23, 24 debouching into the shaft 14 is located a respective connecting opening 60, 61 of a coupling piece 38, 40 of the pipe system 30.
It will be understood that the connection of the tubular coupling piece and a pipe segment can also be realized wherein the pipe segment fits slidably over an open end of the coupling piece.
In particular for a pipe system wherein during use a high degree of condensation can occur along the inner wall of the pipe segments and the coupling pieces, the coupling piece can be configured to receive a pipe segment therein from a second end 49 of the coupling piece and to receive a first end 48 of the coupling piece fittingly in a further pipe segment.
In the installed situation the pipe system is then built up in each case such that the second end 49 of the coupling piece is located higher than the first end 48 of the coupling piece.
In a practical embodiment use is for instance made of pipe segments with fixed lengths in the range of 100-200 cm, preferably with a length of about 160 cm, for use in buildings with storey heights of for instance 270-300 cm, and with pipe segment diameters in the range of 80-250 mm, preferably with diameters of 100, 130, 160 and 200 mm. The coupling pieces can have a length here in the range of 40-60 cm, preferably about 50 cm, wherein the receiving depth for a pipe segment, as measured from the second and 49, amounts for instance to about 32 cm. The diameter of a coupling piece at a respective end 48, 49 is of course adapted here to the diameter of a pipe segment to be received therein. The branch pipe parts have for instance a diameter in the range of 30-80 mm, preferably a diameter of 32 mm or 75 mm, adapted to standard connecting diameters for combustion devices.
The advantages, applications and construction of a ventilation and flue gas discharge system discussed in the foregoing can also be achieved with an embodiment of the invention as shown schematically in figure 9.
The pipe segments are provided herein with at least one outward protruding attaching element, such as an attaching element 50 as discussed in the foregoing. Shown by way of example are a first pipe segment 76 and a second pipe segment 77, each provided with a number of attaching elements 50 distributed tangentially around the outer periphery of a pipe segment and protruding a distance outward. These attaching elements can be attached fixedly to a pipe segment or form part thereof, or be clamped fixedly round a pipe segment 76, 77 by means of a ring element 74, such as a clamping ring or collar. The pipe segments 76, 77 connect movably to each other in length direction in a coupling piece 75 provided with one or more connecting openings 60 for connection thereto of a branch pipe part 71. Further pipe segments connect in turn to each other via a coupling piece 75 (not shown).
As shown in figure 9, the elongate connecting element 47 is now attached to the attaching elements 50 of the first and second pipe segment 76, 77, for instance by means of a pin or pin-like body 55 as discussed in the foregoing. The connecting element 47 extends here along and beyond the coupling piece 75. Expansion and contraction of the pipe segments 76, 77 can be effectively offset in the coupling piece 75 which, in for instance fixedly mounted situation via a branch pipe part 71, can here remain in place. The coupling piece 75 can if necessary also be attached via one or more attaching elements 50 to the connecting element 47, as discussed in the foregoing.
It will be appreciated that a pipe segment 76, 77 provided with attaching elements 50 and/or the ring elements 74, embodied for instance as clamping ring, can also be marketed separately for use with commercially available coupling pieces. Although not shown, a ring element 74 can also be arranged around a coupling piece 75 for the purpose of connecting such coupling pieces to connecting elements 45, 46, 47 in the manner as discussed in the foregoing. The pipe segments can further also be provided with a measurement indicator as discussed in the foregoing in relation to a coupling piece and illustrated in figures 8A and 8B.
The coupling pieces, pipe segments and branch pipes can be manufactured from, among other materials, polypropylene, PP, polybutylene terephthalate, PBT, or polyvinylidene fluoride, PVDF, with wall thicknesses of for instance 2-3 mm.
Although a pipe system is shown in figure 2 and discussed in the foregoing as flue gas discharge channel, it should be appreciated that the pipe system 30 can also be used as ventilation channel, wherein the devices 16, 17, 18 are for instance air discharge devices or air grilles.

Claims

A pipe system for use as ventilation or flue gas discharge channel, comprising at least a first and second pipe segment (35, 36, 37; 76, 77) and at least one elongate connecting element (45, 46, 47) configured to couple the pipe segments (35, 36, 37; 76, 77) movably in length direction to each other, characterized in that the pipe system comprises at least a first and second tubular coupling piece (38, 39, 40; 75) configured to couple the pipe segments (35, 36, 37; 76, 77) via a coupling piece (38, 39, 40; 75) to each other, wherein one of the coupling pieces (38, 39, 40) or the pipe segments (76, 77) is provided with at least one external attaching element (50) configured for the purpose, when pipe segments (35, 36, 37; 76, 77) and coupling pieces (38, 39, 40; 75) are coupled, of attaching the at least one elongate connecting element (45, 46, 47) adjustably in length direction thereto.
The pipe system according to claim 1, wherein the at least one attaching element (50) forms a fixed part of a pipe segment (76, 77), a coupling piece (38, 39, 40) and/or a ring element (74), such as a clamping ring, attachable to a pipe segment or coupling piece, particularly wherein a number of attaching elements (50) are provided which are arranged distributed along the periphery of a pipe segment, coupling piece or ring element.
The pipe system according to one or more of the preceding claims, wherein the at least one attaching element (50) is configured for attachment thereto of a further elongate connecting element (45, 46, 47) for adjustably attaching a further pipe segment (76, 77) or coupling piece (38, 39, 40) of the pipe system to this further elongate connecting element (45, 46, 47) in length direction thereof.
The pipe system according to one or more of the preceding claims, wherein the at least one elongate connecting element (45, 46, 47) and the at least one attaching element (50) are configured to connect to each other via a pin/hole connection, particularly wherein the at least one elongate connecting element (45, 46, 47) is provided with holes (53, 54) arranged distributed in longitudinal direction thereof, wherein the at least one attaching element (50) is eye-shaped (52) for the purpose of attaching the connecting element (45, 46, 47) via a pin-hole-eye connection (52-55) to the attaching element (50).
The pipe system according to claim 4, wherein the at least one elongate connecting element (45, 46, 47) is strip-shaped and the at least one attaching element (50) defines a strip-like receiving slot (51) extending in longitudinal direction of a pipe segment or coupling piece for receiving the strip-like connecting element (45, 46, 47) movably therein, with an eye (52) formed transversely of the strip-like receiving slot (51) for attaching a connecting element (45, 46, 47) to the attaching element (50) via the pin-hole-eye connection (52-55).
The pipe system according to one or more of the preceding claims, wherein the at least one elongate connecting element (45, 46, 47) has a substantially T-shaped or U-shaped cross-section in order to prevent bending or buckling of a connecting element in longitudinal direction.
The pipe system according to one or more of the preceding claims, wherein for connection thereof to each other the at least one coupling piece (38, 39, 40; 75) and the at least one pipe segment (35, 36, 37; 76, 77) are configured to receive the pipe segment fitting movably in the coupling piece from an end thereof, wherein the at least one coupling piece is provided with at least one blocking element (56) for coupling a coupling piece and pipe segment movably to each other over a limited distance in longitudinal direction, particularly wherein the at least one blocking element (56) of the coupling piece is formed as at least one stop for the at least one pipe segment formed internally of the coupling piece at a distance from a respective end.
The pipe system according to one or more of the preceding claims, wherein the coupling piece (38, 39, 40) is provided close to each end with at least one attaching element (50).
The pipe system according to one or more of the preceding claims, wherein the at least one coupling piece (38, 39, 40; 75) is provided between a first and second end thereof with at least one connecting opening (60) for connection thereto of a branch pipe part (41, 42, 43, 71).
The pipe system according to claim 9, wherein the connecting elements (45, 46, 47) each have the same length with at least one attachment point located at a first end (68) thereof for attachment of a coupling piece (38, 39, 40) to an attaching element (50) and with further attachment points (53, 54) arranged relative to each other over a distance from a second end (69) thereof, or from a marking located at the second end (69) on the connecting element, wherein the at least one attaching element (50) and the at least one connecting opening (60) for each coupling piece have a fixed distance and wherein a graduation scale (65) is arranged externally on the coupling piece which extends in longitudinal direction from the attaching element (50) to the at least one connecting opening (60), wherein the graduation scale (65) is provided with a measurement indicator such that, when two coupling pieces are connected to each other in longitudinal direction by a connecting element (45, 46, 47), the longitudinal centre-to-centre distance between the connecting openings (60) of the connected coupling pieces corresponds to the measurement indicator on the coupling piece adjacent to the second end (69) or to the marking on the connecting element (45, 46, 47).
A coupling piece (38, 39, 40), pipe segment (76, 77) and ring element (74) provided with at least one attaching element (50) configured for use in a pipe system according to one or more of the preceding claims, and/or an assembly of such a coupling piece and a pipe segment fixedly connected to the coupling piece, particularly wherein the pipe segment and the coupling piece are welded together.
A method for installing a pipe system according to one or more of the preceding claims in a substantially vertical shaft (14), such as a ventilation or flue gas discharge shaft of a building, wherein the pipe system is inserted into the shaft (14) from an end (15) thereof open to the outside, the method comprising:
- attaching a pipe segment or coupling piece with its at least one attaching element to an elongate connecting element,

- connecting the coupling piece and a pipe segment to each other,

- arranging the pipe segment or coupling piece in the shaft and lowering the coupling piece with the pipe segment connected thereto into the shaft, wherein the connecting element serves as support for further lowering of the pipe system into the shaft, and

- supporting the connecting element such that an end of the pipe segment and the connecting element remains at a distance outside the open end of the shaft.
The method according to claim 12, further comprising:
- connecting a further coupling piece to the end of the pipe segment located outside the shaft,

- connecting a further pipe segment to the further coupling piece,

- attaching the further pipe segment or further coupling piece with its at least one attaching element to the end of the connecting element located outside the shaft,

- attaching a further connecting element to the at least one attaching element of the further pipe segment or further coupling piece,

- lowering the coupled pipe system into the shaft, wherein the further connecting element serves as support as the coupled pipe system is lowered further into the shaft, and

- supporting the further connecting element such that an end of the further pipe segment and the further connecting element remains at a distance outside the open end of the shaft.
The method according to claim 12 or 13, wherein the end of the connecting element located outside the shaft (14) is attached to support means (25-28) engaging on the shaft for supporting the pipe system freely suspended in the shaft (14), in particular for supporting the pipe system freely suspended in two degrees of freedom in the shaft (14).
The method according to claim 12, 13 or 14, wherein the shaft (14) is a ventilation or flue gas discharge channel of a building consisting of multiple storeys, wherein an opening (22, 23, 24) debouching into the shaft is provided on one or more storeys for connection of a branch pipe part (41, 42, 43, 71) to the shaft (14), wherein the pipe system is installed by, starting from a lowest storey, attaching successive coupling pieces with pipe segments at a mutual distance to the successive connecting elements such that, when a pipe system has been installed, at the position where a branch pipe part (41, 42, 43, 71) has to be arranged a connecting opening (60) of a respective coupling piece is located opposite a respective opening (22, 23, 24) debouching into the shaft, particularly wherein the pipe system is assembled and installed such that a connecting opening (60) of a coupling piece of the pipe system is located opposite each opening (22, 23, 24) debouching into the shaft.