AU2008101225B4 - Improvements in current mine ventilation ducts - Google Patents

Description

1 Improvements in current mine ventilation systems FIELD OF THE INVENTION The present invention relates to a mine ventilation system and in particular to a ventilation system comprising two adjacent air ducts that share a common wall. 5 BACKGROUND OF THE INVENTION Mining has long been considered to be a lucrative and yet a dangerous occupation. For that reason there are many facilities provided in mines to ensure that there is no danger to life and that necessary facilities are provided. One of the most obvious requirements in any mine is that the air must be 10 maintained to an acceptable standard. Given that mines can be many kilometres in length most underground mining installations include ventilation ducts that travel along the tunnels to provide air where it is necessary. Typically most such ducts are of a generally cylindrical shape and are hung from the roof of the tunnel. In some tunnels the shape of the tunnel or its operational requirements resulted 15 in two ducts hung next to each other. Under those circumstances, to save on material and avoid having to hang two separate ducts the ventilation ducts were fabricated so that the two ducts shared a common wall, the so called bi-vent ducts. One of the problems of bi-vent ducts that share a common wall is that the fluid or air flow through them is unique to each of the ducts, Accordingly any difference in 20 the air pressure between the two ducts has the effect of acting on their common wall. As air flows through the duct any pressure differential between the two ducts causes the common wall to be moved or flutter in a wave like fashion, the wave travelling along the common wall until it reaches the end of the duct. The constant motion of the common wall leads to the wall deteriorating at a 25 faster then expected rate, results in turbulence that leads to less efficient air flow through the ducts and causes strain on sealing joints that over time can be caused to leak if not break. OBJECT OF THE INVENTION It is an object of the present invention to overcome the above-mentioned 30 problem or at least provide the public with a useful alternative.

2 The present invention successfully addresses these problems by providing for pressure equalization apertures in the common wall, spaced at equal apart intervals along the duct. SUMMARY OF THE INVENTION 5 In a first aspect the invention could be set to reside in a ventilation ducting system for use in mines including: two ducts separated along their length by a common wall, the ducts at each end having an engagement means to engage another duct; a fin extending from said ducts and including apertures to be engaged by supporting 10 members; wherein said common wall includes apertures at spaced apart intervals to allow for air flow between the two ducts. In preference the engagement means includes a spigot having spaced apart apertures to enable a rope to tie two spigots together. 15 In preference a sealing joint extends between adjoining ducts. In preference the apertures are located centrally in the common wall. In preference the apertures are spaced apart every several meters and of generally around 50 millimetres in diameter. BRIEF DESCRIPTION OF THE DRAWINGS 20 The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an implementation of the invention and, together with the description, serve to explain the advantages and principles of the invention. In the drawings: Figure 1 is a perspective view of a bi-vent duct hanging in a tunnel; 25 Figure 2 is a perspective view of the bi-vent duct according to the present invention; and Figure 3 illustrates a single channel duct at one end that converts into a bi vent duct. DESCRIPTION OF THE PREFERRED EMBODIMENTS 3 The following detailed description of the invention refers to the accompanying drawings. Although the description includes exemplary embodiments, other embodiments are possible, and changes may be made to the embodiments described without departing from the spirit and scope of the invention. Wherever possible, the 5 same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts. Turning now to the Figures in detail and there is shown a bi-vent duct 10 comprising of two adjoining ducts 12 and 14 sharing a common wall 16. The bi-vent duct includes a hanging fin 18 that has at spaced apart intervals eyelets 20 that are used 10 to hang the duct by the use of cables 22 that are attached to a typical steel line 24 so that the duct is raised from the floor of a tunnel. The bi-vent ducts typically are made in predetermined lengths and at each end include a spigot 26. The spigots include eyelets 28. Two ducts are then joined together by aligning the eyelets of separate ducts and typically tying them together with rope 30. 15 To assist in maintaining a seal, extending between each of the ducts is a sealing joint 32. The ducts are typically made in multiples of length so that typically there are provided ducts of some 5, 10 and 20 metres in length. The sealing joints are typically some 500 millimetres in length and so extend 250 millimetres into each duct. The vertical extent of the duct is typically around one metre. 20 Eyelets 20 that are used to hang the duct are generally 500 mm apart whilst eyelets 28 on the spigots are generally some 150 mm apart. Illustrated in Figure 3 is a duct that converts form a single cylindrical duct to a bi-vent duct by the addition of an internal common wall 16. As discussed above, such a wall can be caused to flap. For that reason pressure equalising holes or apertures 34 are 25 manufactured within the common wall 16 (Figure 2). These holes are typically located in the middle of the wall height wise and are spaced apart generally every couple of metres. The holes do not have to be of a large size and can be of the order of some 50 mm in diameter. It has been found that the apertures overcome the problem of the common wall flapping and moving about by allowing air 36 to flow between the two 30 ducts thus extending the lifetime of the ventilation ducts and need for maintenance. To provide for strength and durability the ducts are made frmm woven polyethylene fabric extrusions coated with a low resistance film.

4 For the purposes of the specification the word "comprising" means "including but not limited to", and the word "comprises" has a corresponding meaning. Also a reference within the specification to document or to prior use is not to be taken as an admission that the disclosure therein constitutes common general knowledge in 5 Australia. Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope and spirit of the 10 invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Claims (5)

1. A ventilation ducting system for use in mines including: Two ducts separated along their length by an impervious common wall, the ducts at each end having an engagement means to engage another duct; 5 a fin extending from said ducts and including apertures to be engaged by supporting members; wherein said common wall includes apertures at spaced apart intervals to allow for air flow between the two ducts. 10

2. A ventilation ducting system as in Claim 1 wherein said engagement means includes a spigot having spaced apart apertures to enable a rope to tie two spigots together.

3. A ventilation ducting system as in claim I wherein a sealing joint extends 15 between adjoining ducts.

4. A ventilation system as in Claim I wherein the apertures are located centrally in the common wall. 20

5. A ventilation system as in Claim I wherein the apertures are spaced apart every several meters and of generally around 50 millimetres in diameter.