GB2027148A - Improvements in or relating to ducting - Google Patents

Abstract

A length of ducting forming part of for example a ventilation system, in a mine or like underground site, the length of ducting includes a cylindrical sleeve 6 of a flexible, air-tight material the ends of which are each provided with an end ring 8, 10, and a cuff portion 12 secured to one end of the sleeve to form a cylindrical extension of that end of the sleeve. A draw-cord 16 is housed within the free end of the cuff portion such that, on location of the other end ring of one length of ducting in the cuff portion 12 of another length of ducting to be adjacent the one end ring of said other length, said draw-cord can be tensioned to bring said cuff portion into sealing contact with said other end ring to effect an air-tight seal between the two lengths of ducting. <IMAGE>

Description

SPECIFICATION Improvements in or relating to ducting This invention relates to ducting and has .particular, though not exclusive application to flexible ventilation ducting as used in, for example, mines, tunnels and like underground sites.

Ventilation ducting in mines commonly comprises a plurality of interconnected lengths of flexible ducting each consisting of a cylindrical sleeve of pvc coated polyester material, the ends of said lengths being coupled to effect substantially air-tight joints therebetween. The sleeves of material may be provided with outer spiral supports secured thereto if the ducting is to be subjected to suction as well as to force air, although non-supported lengths are quite satisfactory in forcing-along ducting.

There are currently a number of established methods of coupling together the ends of the individual lengths of ducting, all of which suffer from one or more disadvantages.

In one known arrangement the ends of each sleeve each incorporate a spring-steel end ring, and coupling is achieved by means of a separate collar or band. The end rings of the sleeves of the lengths of ducting to be joined are positioned adjacent one another and the collar is piaced over, to surround and cover, the end rings. The collar includes a length of wire rope in the form of two rings which encircle the collar, one ring being positioned to each side of the adjacent end rings of the sleeves. Said length of wire is then tensioned, using a windlass device, about the adjacent ends of the two sleeves to effect a sealed joint therebetween.

It will be appreciated that the collar, being a separate item from the ducting itself, is prone to being mislaid on site. Further, the tension applied to the wire rope is at the discretion of the user.

In an alternative collar, tension is applied to the wire rope by an over-centre clip which ensures correct tension at the coupling, although the collars are still liable to go missing.

It has been proposed to provide coupling means integral with a length of ducting and in the form of a cuff attached to one end of the sleeve.

More particularly, a male end of a length of ducting is provided with a spring-steel end ring.

The other, female end of the length also includes a similar spring-steel end ring but further includes, forming an extension of the sleeve, a cuff integral with, and of the same material as said sleeve and terminating in a further spring-steel ring of smalier diameter than said two end rings. In order to couple two lengths of ducting, the end ring of the male end of one length is inserted through the ring of the cuff on the female end of the other length to be located between said ring and the end ring of said female end. However particularly in the case of spiral-supported (semi-rigid) ducting in which the pitch of the spiral is 75mm, it is very difficult if not impossible to effect the coupling, as the flexibility of the supported sleeve is not such as to enable ready insertion of the male end ring through the ring of the cuff.

According to the present invention there is provided a length of ducting comprising a sleeve of flexible material the ends of: which each incorporate therein an associated end ring, and a cuff portion of a flexible material secured to, to form an extension of, one end of said sleeve, the free end of the cuff portion incorporating therein a peripheral draw-cord, and means for applying tension-to said draw-cord, the arrangement being such that, on insertion of the end ring at the other end of one length of ducting, and on tensioning of the draw-cord around said other end, the cuff portion on the other end of one length of ducting, and one tensioning of the draw-cord around said other end, the cuff portion on the other length of ducting co-operates with said end ring at the other end of the one length of ducting to effect a substantially air-tight seal between the two lengths of ducting.

Preferably the draw-cord is housed within a sheath of a resilient material such as pvc, the ends of said draw-cord extending from said sheath to be attached to tensioning means which conveniently comprises an over-centre clip.

The end rings may each include a length of spring-steel continuous filament wire, preferably received within welded pockets at the associated ends of the sleeve. Conveniently the cuff portion is welded to the one end of the sleeve, the drawcord, which is preferably wire rope, being received within a welded pocket in the free end of the cuff portion.

It will be appreciated that, with such an arrangement, the coupling rhans - i.e. the cuff portion and tensioning means -- is integral with the remainder of the length of ducting, while the adjustable nature of the diameter of the receiving portion of one component to be coupled - i.e. the cuff end pqrtion/draw-cord - enables ready insertion of the end of the other component, thus obviating the major disadvantages of the known arrangements. Further the provision of 'on-oF tensioning means such as an over-centre clip ensures application of the correct tension at all times.

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 longitudinal section through part of two coupled lengths of ducting according to the invention, and Fig. 2 is a detail of Fig. 9.

Referring to the drawings, opposed end extents of two identical lengths of ducting according to the invention and for use in a mine air ventilation system are shown at 2, 4 respectively. Each length consists of a cylindrical sleeve 6 of a flexible, antistatic, non-flammable material such as pvc-coated polyester or nylon. The sleeve may be surrounded by a supporting spiral or wire (not shown) the pitch of which may be 75mm or more.

Housed within a welded pocket at the male end of each sleeve is an end ring 8 comprising a length of spring-steel continuous filament wire the free ends of which are interconnected by a mild steel collar, while a similar end ring 10 is provided in an associated welded pocket at the female end of the sleeve.

The female end of the sleeve further includes, welded thereto, a cuff portion 12 which forms a longitudinal extension of the sleeve and is of the same material as the sleeve. The free end of the cuff portion comprises a welded pocket in which is received a pvc sheath 14 the length of which is just less than the circumference of the free end of the cuff portion whereby the ends of the sheath are located adjacent one another but spaced from one another.

Housed within the sheath 14 is a length of wire rope 1 6 the ends of which project one from each end of the sheath 14. The ends of said rope 1 6 are each connected to an over-centre clip shown schematically at 1 8 in Fig. 1, the arrangement being such that, with the clip in its 'open' or 'off position, the diameter of the free end of the cuff portion 12 is reduced to a value which ensures that said portion 12 is tensioned around, to make substantially sealing contact with, the end ring 8.

This it will be appreciated that such an arrangement enables the male and female ends of two lengths of ducting such as 2, 4 to be coupled together in substantially air-tight relationship much more easily than in known arrangements, without the necessity for much, if any, distortion or deformation of the end rings of the components to be coupled and without the use of any components additional to the lengths of ducting themselves.

The provision of the sheath 14 for the rope 16 serves a number of purposes in that it provides a greater surface area for gripping the male end inserted therein than the rope alone would provide, it prevents tearing of the pocket in the cuff portion 12 that would probably otherwise occur on tensioning of the rope 16, and it results in smooth sliding movement of the rope 16 in the cuff portion thus avoiding ruckling of said cuff portion.

The tensioning means for the rope 16 may be other than an over-centre clip, although it is preferred that said means have an 'on' and an 'off' position which ensures that the same predetermined tension is applied on all occasions by the cuff portion 12 on actuation of said tensioning means.

Although the rope 16 is preferably of wire, other non-stretch materials may be used.

Thus there are provided lengths of ducting incorporating coupling means which enable easy, quick interconnection of said lengths whether they be standard forcing ducting (flat ducting) or semirigid ducting (spiral ducting) with well-spaced (e.g.

1 50mm) or closely spaced (e.g. 75mm) pitches.

The coupling is such as to create a good air-tight joint which does not create much turbulence within the ducting and which can withstand substantial longitudinal tension applied thereto.

Although described in relation to mine ventilation, it will be appreciated that lengths of ducting according to the invention have application in many other situations where a gas flow along a controlled passage is required.

S 1. A length of ducting comprising a sleeve of flexible material the ends of which each incorporate therein an associated end ring, and a cuff portion of a flexible material secured to, to form an extension of, one end of said sleeve, the free end of the cuff portion incorporating therein a peripheral draw-cord, the arrangement being such that, on insertion of the end ring at the other end of one length of ducting into the cuff portion on the one end of another length of ducting, and on tensioning of the draw-cord around said other end, the cuff portion on the other length of ducting cooperates with said end ring of the other end of the one length of ducting to effect a substantially air-tight seal between the two lengths of ducting.

2. A length of ducting as claimed in claim 1 in which the draw-cord is housed within a sheath of resilient material, the ends of said draw-cord extending from said sheath to be attached to tensioning means.

3. A length of ducting as claimed in claim 2 in which the draw-cord is a wire rope.

4. A length of ducting as claimed in claim 2 or claim 3 in which the tensioning means are movable between an inoperative position in which the draw-cord is not tensioned and an operative position in which a predetermined tension is applied to the draw-cord.

5. A length of ducting as claimed in claim 4 in which the tensioning means comprises an overcentre clip.

6. A length of ducting as claimed in any one of claims 1 to 5 in which the end rings each include a length of spring-steel continuous filament wire.

7. A length of ducting as claimed in any ore of claims 1 to 5 in which the end rings are each received within a welded pocket at the associated end of the sleeve.

8. A length of ducting as claimed in any one of claims 1 to 7 in which the cuff portion is welded to the one end of the sleeve, the draw-cord being received within a welded pocket in the free end of the cuff portion.

9. A length of ducting as claimed in any one of claims 1 to 8 in which the sleeve is surrounded by a supporting spiral of wire.

1 0. A length of ducting substantially as described with reference to and as illustrated by the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. of spring-steel continuous filament wire the free ends of which are interconnected by a mild steel collar, while a similar end ring 10 is provided in an associated welded pocket at the female end of the sleeve. The female end of the sleeve further includes, welded thereto, a cuff portion 12 which forms a longitudinal extension of the sleeve and is of the same material as the sleeve. The free end of the cuff portion comprises a welded pocket in which is received a pvc sheath 14 the length of which is just less than the circumference of the free end of the cuff portion whereby the ends of the sheath are located adjacent one another but spaced from one another. Housed within the sheath 14 is a length of wire rope 1 6 the ends of which project one from each end of the sheath 14. The ends of said rope 1 6 are each connected to an over-centre clip shown schematically at 1 8 in Fig. 1, the arrangement being such that, with the clip in its 'open' or 'off position, the diameter of the free end of the cuff portion 12 is reduced to a value which ensures that said portion 12 is tensioned around, to make substantially sealing contact with, the end ring 8. This it will be appreciated that such an arrangement enables the male and female ends of two lengths of ducting such as 2, 4 to be coupled together in substantially air-tight relationship much more easily than in known arrangements, without the necessity for much, if any, distortion or deformation of the end rings of the components to be coupled and without the use of any components additional to the lengths of ducting themselves. The provision of the sheath 14 for the rope 16 serves a number of purposes in that it provides a greater surface area for gripping the male end inserted therein than the rope alone would provide, it prevents tearing of the pocket in the cuff portion 12 that would probably otherwise occur on tensioning of the rope 16, and it results in smooth sliding movement of the rope 16 in the cuff portion thus avoiding ruckling of said cuff portion. The tensioning means for the rope 16 may be other than an over-centre clip, although it is preferred that said means have an 'on' and an 'off' position which ensures that the same predetermined tension is applied on all occasions by the cuff portion 12 on actuation of said tensioning means. Although the rope 16 is preferably of wire, other non-stretch materials may be used. Thus there are provided lengths of ducting incorporating coupling means which enable easy, quick interconnection of said lengths whether they be standard forcing ducting (flat ducting) or semirigid ducting (spiral ducting) with well-spaced (e.g.

1 50mm) or closely spaced (e.g. 75mm) pitches.

The coupling is such as to create a good air-tight joint which does not create much turbulence within the ducting and which can withstand substantial longitudinal tension applied thereto.

Although described in relation to mine ventilation, it will be appreciated that lengths of ducting according to the invention have application in many other situations where a gas flow along a controlled passage is required.

S 1. A length of ducting comprising a sleeve of flexible material the ends of which each incorporate therein an associated end ring, and a cuff portion of a flexible material secured to, to form an extension of, one end of said sleeve, the free end of the cuff portion incorporating therein a peripheral draw-cord, the arrangement being such that, on insertion of the end ring at the other end of one length of ducting into the cuff portion on the one end of another length of ducting, and on tensioning of the draw-cord around said other end, the cuff portion on the other length of ducting cooperates with said end ring of the other end of the one length of ducting to effect a substantially air-tight seal between the two lengths of ducting.

2. A length of ducting as claimed in claim 1 in which the draw-cord is housed within a sheath of resilient material, the ends of said draw-cord extending from said sheath to be attached to tensioning means.

3. A length of ducting as claimed in claim 2 in which the draw-cord is a wire rope.

4. A length of ducting as claimed in claim 2 or claim 3 in which the tensioning means are movable between an inoperative position in which the draw-cord is not tensioned and an operative position in which a predetermined tension is applied to the draw-cord.

5. A length of ducting as claimed in claim 4 in which the tensioning means comprises an overcentre clip.

6. A length of ducting as claimed in any one of claims 1 to 5 in which the end rings each include a length of spring-steel continuous filament wire.

7. A length of ducting as claimed in any ore of claims 1 to 5 in which the end rings are each received within a welded pocket at the associated end of the sleeve.

8. A length of ducting as claimed in any one of claims 1 to 7 in which the cuff portion is welded to the one end of the sleeve, the draw-cord being received within a welded pocket in the free end of the cuff portion.

9. A length of ducting as claimed in any one of claims 1 to 8 in which the sleeve is surrounded by a supporting spiral of wire.

1 0. A length of ducting substantially as described with reference to and as illustrated by the accompanying drawings.