GB2194036A - Ventilation ducting for underground passageways - Google Patents

Abstract

Ventilation ducting for underground passageways comprises two series of alternately interconnected lengths (2,4) of rigid ducting, each length (2,4) including a hollow cylindrical body portion (6,14). The lengths (2) of the first series each include a circumferential flange (8) within one end thereof defining an annular receiving channel (10) within said one end of the length (2), while the lengths (4) of the second series each include a circumferential flange (16) extending externally around one end thereof defining an annular receiving channel (18). On assembly, the other ends of the lengths (2,4) of the first and second series are each received within the corresponding annular channels (18,10) of the one ends of the lengths (4,2) of the second and first series respectively to form a continuous ventilation ducting, while, for storage and transportation purposes, a length (4) of the second series can be nested within a length (2) of the first series. Resilient sealing rings 12 may be incorporated within the channels. Adjacent ducts may be lashed together by straps engaging wire loops fixed externally to the ducts. <IMAGE>

Description

SPECIFICATION Improved ventilation ducting for underground passageways This invention relates to ventilation ducting for underground passageways and more particularly to such ducting for use in auxiliary ventilation systems provided in underground mine roadways and like situations to supplement the primary ventilation therein.

In the formation of underground roadways, and as the roadway progresses further from the shaft, the primary systems provided to ventilate the underground workings eventually become incapable of feeding sufficient volume of air under pressure to regions that are further than a predetermined distance from the shaft.

Accordingly, it has become common practice to supplement these primary systems with auxiliary ventilation systems comprising fans and ducting at these remote locations.

For forced ventilation purposes-i.e. when supplying fresh air at positive pressure-it is convenient for the ducting of the auxiliary systems to be of the flexible lay-flat type because such ducting can be readily transported in compact form to the necessary locations.

However, if the auxiliary systems are to be used for exhaust purposes where the interior of the ducting is subjected to negative pressure, the ducting itself must be of a circumferentially rigid nature to withstand those negative forces, and it is clearly not possible to use the flexible lengths desirable for forced ventilation.

The transportation of rigid lengths of ducting to remote locations underground is much more difficult and time-consuming than with the flexible lengths, although the rigid ducting does have the advantage of superior performance, in that the smooth internal wall keeps to a minimum the resistance to air flow along the ducting. This can be compared with the undulating form of the internal walls of the alternative exhaust ducting, namely spiral-reinforced flexible tubing the configuration of the internal walls of which results in relatively inefficient transfer of air therealong.

Although, as mentioned above, the transportation of rigid lengths of ducting, which may typically be up to 6 metres in length and up to of the order of 1200mm in diameter, is somewhat tedious, the transport systems for so doing are now well established.

It would be desirable to produce rigid ducting which could utilise the established transport systems but in a more efficient manner.

According to the present invention there is provided ventilation ducting for use in underground passageways and consisting of a plurality of interconnected lengths of ducting each of a rigid material, alternate lengths of said ducting comprising a first series and the other lengths of said ducting comprising a second series, each length of the first series including a hollow cylindrical body portion within one end of which is formed a circumferential flange defining, together with said one end of the body portion, an annular receiving channel within said body portion, and each length of the second series including a hollow cylindrical body portion around one end of which is formed a circumferential flange defining, together with said one end of the body portion, an annular receiving channel externally of said body portion, the diameters of the lengths of ducting of the first and second series being such that, on assembly: a) the other end of the body portion of a length of the first series can be received in the annular channel around the one end of the body portion of an adjacent length of the second series; b) the other end of the body portion of a length of the second series can be received in the annular channel within the one end of the body portion of an adjacent length of the first series, and, for storage purposes; c) the body portion of a length of the second series can be located within the body portion of a length of the first series.

Thus it will be appreciated that ventilation ducting can be readily assembled by interconnecting, alternately, lengths of said first series with lengths of said second series to provide a continuous run, while the facility for locating each length of the second series within an associated length of the first series enables two lengths to be transported as one using the above-mentioned established transport systems, and also halves the storage space necessary for the ventilation ducting as a whole prior to assembly.

Preferably the lengths of ducting are each of glass fibre-reinforced plastic, although they may be of metal, while it is further preferred that sealing means, conveniently compressible neoprene rings, are provided in the channels of the lengths of the first and second series.

The ventilation ducting preferably includes retaining means for interconnecting adjacent lengths, which retaining means may comprise a plurality of circumferentially-spaced loops located at or adjacent each end of each length of ducting, and a plurality of straps adapted to interconnect the loops of adjacent# ends of adjacent lengths and urge said lengths axially to wards one another.

By way of example only, an embodiment of the invention will now be described in greater detail with reference to the accompanying drawings of which: Fig. 1 is a schematic longitudinal Section through ventilation ducting according to the in vention; Fig. 2 is a longitudinal section through a length of the second series of ducting accord ing to the invention located within a length of the first series, and Fig. 3 and 4 show a length of the first series and a length of the second series respectively of ventilation ducting according to the invention.

Referring to the drawings, there is illustrated ventilation ducting comprising a series of interconnected lengths, alternate lengths of ducting being the same as each other and forming a first series of lengths 2, and the other lengths being the same as each other and forming a second series of lengths 4.

More particularly, each length 2 of the first series includes a cylindrical body portion 6 of glass fibrereinforced plastic in one end of which is provided an annular flange or lip 8 defining together with said one end extent of the body portion 6, an annular channel or groove 10 in which is located a sealing ring 12, preferably of neoprene or like compressible material.

Each length 4 of the second series similarly includes a cylindrical body portion 14 of glass fibre-reinforced plastic the diameter of which is slightly less than that of the body portions 6 for reasons which will become apparent. A circular flange or lip 16 is provided around one end of the body portion 14 to define, together with said one end extent of the body portion 14, an annular channel or groove 18 in which is located a sealing ring 20 of neoprene or like compressible material.

Each length of ducting 2 and 4 has a plurality of circumferentially-spaced wire loops 22 secured thereto around each end thereof, there being typically four loops per end each spaced apart by 90 .

The dimensions of the body portions 6,14 and the channels 10,18 of the lengths 2,4 are such that ventilation ducting as shown in Fig.

1 can be assembled by locating the other end of each body portion 14 in the channel 10 formed within the one end of an adjacent body portion 6, and by locating the other end of each body portion 6 in the channel 18 formed around the one end of an adjacent body portion 14 whereby a continuous run comprising alternate lengths 2,4 is formed.

Adjacent lengths 2,4 are secured together by means of straps extending between the wire loops 22 positioned around adjacent ends of said lengths, said straps applying axial forces to the ducting whereby the other ends of the body portions 6,14 are urged against the sealing rings 20,12 in the associated channels 18,10.

The dimensions of the body portions 6,14, and in particular the diameters thereof, are such that the major advantage shown in Fig. 2 is achieved.

More particularly, a body portion 14 can be located within a body portion 6 as shown in that figure, with the flanges 8,16 located at opposite ends of the assembly. Thus the internal diameter of the body portion 6 is slightly greater than the external diameter of the body portion 14 plus the loops 22 to enable said location one within the other.

It will be appreciated that two duct lengths can therefore be transported as one by established transport systems, while storage space for the ducting is correspondingly halved compared with that required for conventional rigid ducting.

In assembling duct lengths transported as shown in Fig. 2, it is merely necessary to remove the length 4 from within the length 2, turn the length 4 round and insert the other end thereof into the channel 10 on the length 2. The male/female interconnection provided by means of the channels 10 and 18 can be readily achieved even by non-skilled workers.

Clearly the precise construction of the end regions of the duct lengths 2,4, including the precise configurations and depths of the annular channels 10 and 18, as well as the means for interconnecting adjacent lengths, can be varied from that shown without departing from the scope of the invention.

Claims (7)

1. Ventilation ducting for use in underground passageways and consisting of a plurality of interconnected lengths of ducting each of a rigid material, alternate lengths of said ducting comprising a first series and the other lengths of said ducting comprising a second series, each length of the first series including a hollow cylindrical body portion within one end of which is formed a circumferential flange defining, together with said one end of the body portion, an annular receiving channel within said body portion, and each length of the second series including a hollow cylindrical body portion around one end of which is formed a circumferential flange defining, together with said one end of the body portion, an annular receiving channel externally of said body portion, the diameters of the lengths of ducting of the first and second series being such that, on assembly:: a) the other end of the body portion of a length of the first series can be received in the annular channel around the one end of the body portion of an adjacent length of the second series; b) the other end of the body portion of a length of the second series can be received in the annular channel within the one end of the body portion of an adjacent length of the first series, and c) the body portion of a length of the second series can be located within the body portion of# a length of the first series.

2. Ventilation ducting as claimed in claim 1 in which the lengths of ducting are each of glass fibre-reinforced plastic.

3. Ventilation ducting as claimed in claim 1 or claim 2 in which sealing means are provided in the annular receiving channels of the lengths of the first and second series.

4. Ventilation ducting as claimed in claim 3 in which the sealing means comprise compressible neoprene rings.

5. Ventilation ducting as claimed in any one of claims 1 to 4 and including retaining means for interconnecting adjacent lengths of ducting.

6. Ventilation ducting as claimed in claim 5 in which the retaining means comprise a plurality of circumferentially-spaced loops located at or adjacent each end of each length of ducting, and a plurality of straps adapted to interconnect the loops of adjacent ends of adjacent lengths and urge said lengths axially towards one another.

7. Ventilation ducting substantially as described with reference to and as illustrated by the accompanying drawings.