WO2000020794A1

WO2000020794A1 - An air relief pipe

Info

Publication number: WO2000020794A1
Application number: PCT/DK1999/000513
Authority: WO
Inventors: Tonni Olesen
Original assignee: Tonni Olesen Vvs-Teknik
Priority date: 1998-10-01
Filing date: 1999-09-30
Publication date: 2000-04-13
Also published as: AU5850299A; WO2000020794A8; DK199800367U4; EP1125081A1

Abstract

The invention concerns an air relief pipe (10, 11) for use in connection with pipe installations in which a medium in fluid state is transported, primarily water. The air relief pipe has an inlet and an outlet for the fluid medium, said inlet and outlet each being connected to medium pipes (2, 3) in the pipe installation, and has an outlet for air or other gases which have been contained in the fluid medium. The innovative feature of the invention is that between the inlet and the outlet for the fluid medium, the air relief pipe has a flow area that is greater than the flow area for the inlet and the outlet for the fluid medium. There is hereby effected a reduction in the flow rate, so that it is easier for air bubbles to rise up in the air relief pipe and be collected in same.

Description

An air relief pipe

Areas of application of the invention

The invention concerns an air relief pipe for use in connection with pipe installations in which a medium in fluid state, primarily water, is transported. The air relief pipe has an inlet and an outlet for the fluid medium, said inlet and outlet each being connected to the medium pipe of the pipe installation, and an outlet for air and other gases, which have been contained in the fluid medium. Between the inlet and the outlet for the fluid medium, the air relief pipe has a flow area, which is greater than the flow area for the inlet and the outlet for the fluid medium.

The invention can be used, for example, for building into closed, water-carrying circulation plants such as e.g. heating and cooling plants, for the removal of an undesired content of air in the circulation medium, and herewith improved circulation of the medium.

The known technique

Hitherto-known forms of air venting devices consist typically of bleeder arrangements which are built directly into the medium pipes, and which consist e.g. of a T-piece or a sleeve with a stub having a manual bleeder screw connected to its top, an automatic bleeder valve or an air escape valve. These known types of air venting arrangements, which are built into the pipe installation at its highest point or at the highest point of a part of the installation, function in such a manner that air bubbles which are in circulation with the medium, and which happen to pass immediately under the stub, can escape through the air venting arrangement.

With these hitherto-known forms of air relief pipes, any undesired air which is supplied to the installation will not be able to be removed from the medium in one passage of the air relief pipe during circulation, but will require to be vented over longer periods of operation, in that only a smaller part of the air bubbles con- tained in the medium will escape out of the venting arrangement for each passage of the air relief pipe.

Moreover, air relief arrangements of the kind disclosed in the introduction are known, and whereby the fluid medium in the air relief pipe will be exposed to a braking effect or a reduction in the flow rate due to the greater flow area, so that the content of air in the medium, e.g. in the form of air bubbles, can escape easier, in that the air has more time to rise up to the top of the air relief pipe.

Air relief pipes of this kind are known from Danish publication no. 161 480 and German publication no. 38 31 912. The first-mentioned of these publications discloses an air relief pipe which has the inlet and the outlet for the fluid medium at its ends, but has a relatively complicated construction with a partly through-going pipe part which is encapsulated in a pipe part with a larger diameter, the latter pipe part being provided with closed end parts through which the first-mentioned pipe part must pass in a fluid-tight connection. From the point of view of production technique, this involves a relatively complicated construction. The latter publication discloses a construction in which a pipe part, which stands substantially vertical, has connections for the medium pipes at the uppermost part of the side. The lowermost part of this pipe part is configured as a removable part, which must thus be mounted while forming a fluid-tight assembly. The uppermost part of the construction, on which there is also mounted a venting arrangement, is similarly a relatively complicated construction, where among other things the connection pipes are configured with bends and are connected to the tubular vertical part with complicated angle proportions which will make production difficult.

The technical problem which needs to be solved

With the invention, it is desired to provide an air relief pipe, which overcomes the drawbacks of the hitherto-known venting arrangements, in that it is especially desired to provide an air relief pipe with which the venting of a pipe installation can be effected more quickly and with a more reliable result than with the known venting arrangements, and which at the same time is of a relatively simple configuration, so that the air relief pipe can be produced in a more simple manner than the above-mentioned known configurations.

The new technique

The innovative aspect of the invention is that the air relief pipe consists of a tubular element which has a reduced diameter at both ends and is provided with connection stubs or the like, and which on the side is provided with at least one connection stub.

The technical effect

By using the above-mentioned new technique in connection with the said known technique, it is possible to provide an air relief pipe which is not encumbered with the disadvantages discussed in connection with the known technique, but which has a surprisingly simple configuration, which is advantageous from the point of view of production.

As disclosed in claim 2, it is expedient that the flow area for the air relief valve is at least twice as large as the flow area for the inlet and outlet, and preferably approx. three times larger. In that the venting takes place by the building of air relief pipes in the highest points of the installation, it is hereby achieved that the highest point of the installation is raised by the larger diameter of the air relief pipe, so that the highest point will be more pronounced. If, for example, the air relief pipe is built into a pipe piece, which lies horizontally, irregularities in the horizontal extent will no longer have any particular influence on where the highest point lies, in that this will still be the top of the air relief pipe.

It can be expedient for an embodiment of the air relief pipe to be configured as disclosed in claim 3, this embodiment being especially applicable for building into pipe installations, which extend horizontally.

An alternative embodiment, which is configured as disclosed in claim 4, has two connection stubs on the side, one of which can be used for a venting arrangement, while the other can be plugged-off or e.g. used for a sensor. This embodiment can expediently be configured as disclosed in claim 5, whereby the air relief pipe can be built into a pipe installation in which the pipes extend at an angle.

As disclosed in claim 7, the air relief pipe according to the invention can be provided with a bleeder screw, an automatic bleeder or a combination of both. As characterised in claim 8, the connection stubs can be configured as threaded stubs which are used in connection with medium pipes with connection threads, or as stubs which are intended for connection to pipe installations by welding, soldering or the like.

In the following, the invention and particularly advantageous embodiments will be explained in more detail with reference to the drawings.

The drawings

Fig. , 1 shows a known air relief pipe, which is provided with a bleeder screw, fig. 2 also shows a known air relief pipe, which is provided with an auto- matic venting arrangement, fig. 3 shows another known air relief pipe in a raised version, fig. 4 shows yet another known air relief pipe which is provided with an air escape arrangement, fig. 5 shows an air relief pipe according to the invention, ffiigg.. 6 6 shows the air relief pipe shown in fig. 5 on a larger scale and partly in section, fig. 7 shows a second embodiment of an air relief pipe partly in section, said embodiment being intended for mounting on pipes extending at an angle, fig. 8 shows the embodiment shown in fig. 7 provided with an insulating layer, fig. 9 shows the air relief pipe shown in fig. 5 built into an installation, fig. 10 shows a cross-section along the line X-X of the embodiment shown in fig. 6, fig. 11 also shows a cross-section along the line X-X of the embodiment shown in fig. 6, but where the air relief pipe is turned to the one side out of regard for an overlying ceiling or the like, and fig. 12 shows an isometric pipe diagram of a plant in which different possibilities for the use of the air relief pipe according to the inven- tion are illustrated.

Example embodiments

Air relief pipes of already-known types are shown in different embodiments in figs. 1- 4, where a part of a pipe installation with a known air relief pipe 1 is seen from the side, in that a section has been taken through the pipe insulation 8, which on the outside is surrounded by the insulation jacket 9. The known air relief pipe, which mainly consists of a short sleeve or T-piece, is connected at each end to medium pipes 2 and 3 which, for example, form part of a circulation plant e.g. for water. Upwardly, the air relief pipe has a stub which is connected as shown to a bleeder screw 4 (fig. 1 ) or an automatic bleeder 5 (fig. 2). The air bubbles, which pass through the pipe system, and consequently pass under the stub, can thus escape through the bleeder screw 4 when this is opened, or can escape through the automatic bleeder 5.

As shown in fig. 3, the known air relief pipe 1 can be provided with a pipe piece 6, which raises the bleeder screw (or an automatic bleeder) higher up, so that the collection point for the air bubbles lies at a higher level. Finally, as shown in fig. 4, the known air relief pipes can be used in connection with an air pot 7 where the bubbles can collect, and thus consequently be allowed to escape ei- ther via a bleeder screw 4 (or alternatively by means of an automatic bleeder). As illustrated by the stippled lines, air pots 7 of various sizes can be used.

The air relief pipe according to the invention is shown in fig. 5 in an embodiment 10 which, in the same manner as the known air relief pipes shown in figs. 1-4, is inserted between two medium pipes 2 and 3 which extend in the same direction, and at a place which lies highest or almost highest in the installation or in the relevant part of the installation. As will be seen, the air relief pipe 10 comprises a main pipe 12 with a greater diameter than the medium pipes 2 and 3. This main pipe is provided at its ends with connection stubs 15 and 16 with which the con- nection to the medium pipes 2 and 3 is established. On the side of the main pipe 12 there is provided a further connection stub 17 for an air escape arrangement, which, for example, can be an automatic bleeder 5 as shown.

When the fluid medium passes the air relief pipe 10, the medium, due to the lar- ger diameter of the main pipe 12, will have a smaller flow rate, whereby it will be easier for air or gas bubbles to release themselves from the fluid and collect uppermost in the air relief pipe 10 and in the connection stub 17 with associated air escape arrangement. Moreover, because of the greater diameter of the main pipe, the top of the air relief pipe will reach a higher level than the remainder of the pipe installation, and will thus to a more pronounced degree constitute the highest point in the pipe installation, and thus for this reason air and gas bubbles will consequently collect here.

In the following, the air relief pipe 10 will be described in more detail with refer- ence to fig. 6, which on a larger scale and partly in section shows the air relief pipe alone in connection with two medium pipes 2 and 3. The main pipe 12 is provided at both ends with reduction pieces 13 and 14 that, for example, can be configured by swaging or extrusion. At the ends of these reduction pieces 13 and 14 there are mounted connection stubs 15 and 16, e.g. by welding 19. In the embodiment shown, these connection stubs are provided with an internal thread 20 corresponding to an external thread 21 on the end of the medium pipes 2 and 3. However, alternative use can be made of stubs of other forms, which are intended for connection to medium pipes by welding, soldering or the like. The connection stub 17 for the bleeder arrangement is mounted on the side of the main pipe 12, and substantially in the centre in the longitudinal direction. This stub is also mounted by welding as indicated by the welding seams 19, and this stub also has an internal thread 20. However, this stub can naturally also be of the type, which is intended for further connection by means of welding, soldering or the like.

A second embodiment of the invention is shown in fig. 7, similarly shown in section. This air relief pipe 1 similarly consists of a main pipe 12 that has reduction pieces 13 and 14 at its ends on which connection stubs 15 and 16 with internal thread 20 are mounted by welding 19. On the side of the main pipe 12 and approximately in the centre in the longitudinal direction, a connection stub 17 is mounted by welding 19. Moreover, on the side of the main pipe 12 and in the vicinity of its one end, a further connection stub 18 is mounted by welding 19, said stub 18 in the embodiment shown also having an internal thread 20.

This embodiment of the invention is intended for mounting in a pipe installation in which the incoming medium pipe and the outgoing medium pipe extend at right angles to one another. As shown in the figure, the one medium pipe 2 is thus connected to the stub 18, while the other medium pipe 3 is connected to the stub at the end of the main pipe 12, preferably the connection stub 16 which lies furthest away from the connection stub 18. The air relief pipe 11 can be used in two fundamentally different positions, i.e. either with the longitudinal axis of the main pipe 12 lying substantially horizontal, such as shown in fig. 7, or with the longitu- dinal axis disposed substantially vertical. In the former application, the venting arrangement will be connected to the connection stub 17, while the connection stub 15 will be plugged or possibly used for the mounting of a sensor, e.g. a temperature sensor. In the latter application, where the medium pipe 2 extends horizontally and the medium pipe 3 extends vertically downwards, the venting arrangement will be connected to the connection stub 15, while the connection stub 17 here will be plugged or be used for the mounting of a sensor or the like.

In both of the above-mentioned cases the two connection stubs 16 and 18 should be of the same dimension, corresponding to the dimension of the medium pipes, while the dimensions of the two remaining connection stubs 15 and 17 will correspond to the dimension for the venting arrangement.

The air relief pipe according to the invention can be produced in a number of different sizes, corresponding to different sizes of medium pipes, so that a suitable relationship is ensured between the flow area for the main pipe of the air relief pipe and the flow area for the medium pipes. It is hereby ensured that the flow in the air relief pipe is suitably slowed down without the size of the air relief pipe becoming disproportionately great. Moreover, the length of the main pipe can be adapted in relation to the diameter of the main pipe, so that a suitably long through-flow time is ensured, whereby it is ensured that the air bubbles are collected in the air relief pipe.

In the following, a number of examples are provided in table form of the dimen- sions of the air relief pipe's main pipe for a series of medium pipes of commonly- used dimensions, and in each case the relationship is shown between the flow area for the main pipe and the flow area for the medium pipes.

Medium pipes in the form of pipes with pipe threads shown in commonly used inch sizes: Medium pipes Air relief pipe Relationship between

(Inches) (Main pipe) flow areas

Outside diameter Nominal length (main pipe/medium pipe)

3/8" 33.7 mm 150 mm 5.28 1/2" 42.4 mm 150 mm 5.34

3/4" 48.3 mm 150 mm 3.98

1" 60.3 mm 175 mm 4.01

1 1/4" 76.1 mm 200 mm 3.81

1 1/2" 88.9 mm 225 mm 3.88 2" 114.3 mm 250 mm 4.01

Medium pipes of the welding-in type, shown with outside diameter of commonly used sizes:

Medium pipes Air relief pipe Relationship between

(Main pipe) flow areas

Outside diameter Outside diameter Nominal length (main pipe/medium pipe)

17.2 mm 33.7 mm 150 mm 4.39

21.3 mm 42.4 mm 150 mm 4.62

26.9 mm 48.3 mm 150 mm 3.74

33.7 mm 60.3 mm 175 mm 3.66

42.4 mm 76.1 mm 200 mm 3.57

48.3 mm 88.9 mm 225 mm 3.66

60.3 mm 114.3 mm 250 mm 3.86

76.1 mm 133.0 mm 300 mm 3.16

As will be seen, with the shown examples of air relief pipes there is ensured a ratio between the flow area for the main pipe and the flow area for the medium pipes which is above approx. 3 and which extends in excess of 5. On the other hand, for the air relief pipes with the lowest ratio values the length of the main pipe has been made relatively greater, in practice, the air relief pipes can be produced with dimensions, which ensure a ratio, which lies between approx. 2 and approx. 10.

In fig. 8 there is shown an air relief pipe 11 corresponding to the embodiment discussed above in connection with fig. 7. The elements, which are already discussed in connection with fig. 7, are indicated with the same reference numbers as in fig. 7, and therefore will not be discussed again. However, in fig. 8 it is further shown how the installation will appear after insulation of the medium pipes with pipe insulation consisting of, e.g., a 40mm insulation, which is confined within an outer insulation jacket 9. The pipe insulation 8 is applied only to the medium pipes 2 and 3, and for comparison the extent of the pipe and insulation is shown with stippled lines, had there not been any air relief pipe mounted, but only in a 90° bend. As will be seen, the installation with air relief pipe 11 will not exceed the extent of pipes with associated insulation to any substantial degree. For this reason, the air relief pipe according to the invention will find easier application than the known air relief pipes with, for example, air pots, in places where an overlying ceiling or roof construction imposes limitations on the size of the components used. Since the air relief pipe does not fill substantially more than the remaining pipe installation with insulation, it will be expedient to provide the air relief pipes with identification markers or the like, e.g. for affixing to the finished pipe insulation, so that the air relief pipes can be easier located later.

Fig. 9 shows the use of an air relief pipe according to the invention in connection with an installation such as e.g. a central heating plant. An air relief pipe 10 is mounted in the plant between two medium pipes 2 and 3 which extend a short distance below a ceiling, a roof construction 22 or the like, and which is provided with pipe insulation 8 and 9. The connection stub 17 for the air relief pipe is connected via a nipple piece 24 to a T-piece 25. This is connected at the top to an automatic air bleeder 5, while at the side it is connected to an air relief pipe 26, which is led to and down a wall 23. The air relief pipe 26 is secured to the wall 23 by means of pipe brackets 27, and at the bottom a manual air escape cock 28, e.g. a ball cock, terminates it. At the end of this air escape cock 28 there is a screw cap 29 which can be secured to the wall e.g. by means of a chain 30.

This construction which has both a manual air escape 28 and an automatic air bleeder 5 has the advantage that, for example, in connection with the filling and the start-up of the plant, or with greater subsequent filling, there can immediately be effected a manual venting by means of the manual air escape cock 28 with dismounted screw cap 29. During operation, the removals of small amounts of air take place through the automatic bleeder 5. The manual air escape is led downwards for practical reasons, in that as a rule the air relief pipe 10 with associated venting arrangement is installed close to an overlying building construction 22, and therefore will not be immediately accessible for easy operation.

In figs. 10 and 11 the air relief pipe according to the invention is shown in a section, which in fig. 6 is shown by the line X-X. There is thus seen a section of the medium pipe 2 which leads into the connection stub 15 which is seen from the end. Also seen is the weld seam 19 with which the connection stub 15 is secured to the reduction piece 13 of the air relief pipe 10. Figs. 10 and 11 also show the cross-section of the pipe insulation 8 with jacket 9. Finally, in figs. 10 and 11 is seen the connection stub 17 for the air venting arrangement, said connection stub being mounted by means of weld seam 19. In fig. 10, the air relief pipe 10 is shown in the position in which it is normally used, where the connection stub 17 points vertically upwards. However, when the space upwards is limited by e.g. a ceiling construction 22, the air relief pipe 10 is turned to one of the sides, such as shown in fig. 11. Space can hereby still be found for the venting arrangements etc., and the effect of the air relief pipe 10 will not be reduced, in that the relatively large diameter of the air relief pipe 10 will ensure that air bubbles will nevertheless find their way up into the connection stub 17.

In fig. 12 is shown an isometric pipe diagram of a pipe installation, for example a part of a central heating plant, where an air relief pipe according to the invention is shown mounted in different places. The pipe installation has two pipe systems, i.e. a feed pipe 31 and a return pipe 32, both of which in the horizontal extent comprise a stopcock such as ball cock 33 and a thermometer 34. The pipes are shown running parallel, and in each branch on a part which extends horizontally there is mounted an air relief pipe 10, each of which has an air bleeder screw 4 (or alternatively an automatic air escape arrangement). At the place where the pipes systems change from extending horizontally to extending vertically, an air relief pipe 11 is mounted in each system. In the feed pipe 31 the air relief pipe 11 is mounted with its longitudinal axis extending vertically, while the air relief pipe in the return pipe 32 is mounted with the longitudinal axis extending horizontally. In both cases, an air bleeder screw 4 (or alternatively an automatic bleeder arrangement) will be mounted in such a manner that it faces upwards. The connection stub 17 in the feed pipe 31 will thus be plugged or used for a sensor or the like, while in the return pipe 32 it is the connection stub 15 which must be plugged or used for a sensor or the like.

The air relief pipe according to the invention can, for example, be produced from smooth, seamless steel pipe on which sleeves or stubs are welded. The air relief pipe can, however, also be produced from thin-walled stainless steel pipes or from copper pipes. The air relief pipe can possibly be treated afterwards, e.g. it can be painted or galvanised, with the object of preventing corrosion, but it can naturally also be used in the untreated state.

With the object of removing especially the smallest air bubbles (micro-bubbles), the air relief pipes can possibly be provided with a built-in air-trap, e.g. in the form of sharp-edged and/or twisted blades of stainless steel plate for increasing the efficiency.

Claims

1. Air relief pipe (10, 11) for use in connection with pipe installations in which a medium in fluid state is transported, primarily water, said air relief pipe having an inlet and an outlet for the fluid medium, said inlet and outlet each being connected to medium pipes (2, 3) in the pipe installation, and having an outlet for air or other gases, which have been contained in the fluid medium, said air relief pipe having a flow area between the inlet and the outlet for the fluid medium which is greater than the flow area for the inlet and the outlet for the fluid me- dium, characterized in that the air relief pipe (10, 11) consists of a tubular element (12) which has a reduced diameter (13, 14) at both ends and is provided with connection stubs (15, 16) or the like, and on the side of which there is provided at least one connection stub (17).

2. Air relief pipe according to claim 1, characterized in that the flow area of the air relief pipe is at least twice as large as the flow area for the inlet and the outlet for the fluid medium, and preferably approx. three times larger.

3. Air relief pipe according to claim 1 or 2, characterized in that the con- nection stubs (15, 16) or the like at both ends of the air relief pipe (10, fig.6) are intended for connection to the pipe installation's medium pipes (2, 3), and that a connection stub (17) on the side of the air relief pipe is intended for connection to an air venting arrangement.

4. Air relief pipe according to claim 1 or 2, characterized in that the air relief pipe (11, fig.7) is provided on its side with two connection stubs (17, 18), in that the one (18) of these is placed on substantially the opposite side to the other (17), and in the vicinity of one end of the air relief pipe.

5. Air relief pipe according to claim 4, characterized in that the connection stub (18) which is placed on the side of the air relief pipe and in the vicinity of one of its ends, and the connection pipe (16) which is placed at the other end of the air relief pipe, are intended for connection to the pipe installation's medium pipes (2, 3).

6. Air relief pipe according to claim 5, characterized in that each of the two remaining connection stubs (15, 17) can be used as the connection for an air venting arrangement, and that the latter connection stub can possibly be used as connection for a sensor such as, for example, a temperature sensor.

7. Air relief pipe according to one or more of the claims 1-6, characterized in that the air relief pipe can comprise a bleeder screw (4), an automatic bleeder (5) or a combination of both.

8. Air relief pipe according to one or more of the claims 1-7, character- i z e d in that the said connection stubs (15, 16, 17, 18) can be configured as threaded stubs or as stubs which are intended for connection by welding, soldering or the like.