GB2320682A

GB2320682A - Fire resistant cartridge for a ventilation system

Info

Publication number: GB2320682A
Application number: GB9721687A
Authority: GB
Inventors: Juergen F Eidmann; Karin Wepierre
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-10-14
Filing date: 1997-10-13
Publication date: 1998-07-01
Anticipated expiration: 2017-10-13
Also published as: GB2320682B; FR2754460B1; GB9721687D0; FR2754460A1

Abstract

The cartridge 3 is housed in a sleeve 2 which has a bead 4 projecting around the inside of it's bore enabling the cartridge to be mounted in the sleeve via snapping lugs 24 engaging the bead. The cartridge typically contains closable shutters 8A and 8B operated by a fusible link which gives way at a suitable temperature threshold. The sleeve containing the cartridge is generally sealed in the opening of a wall and connects the respective ends of a ventilation pipe.

Description

1 2320682 FIRE RESISTANT ASSEMBLY, CARTRIDGE AND SHELL FORMING A PART

THEREOF AND METHOD FOR PROVIDING A VENTILATION SYSTEM WITH SUCH AN ASSEMBLY The invention relates ventilation systems.

to f ire resistant assemblies for It is known that such assemblies are designed to be inserted in the system at points at which the latter passes through a partition, the fire resistant assembly closing in the event of fire in order to avoid propagation thereof through the ventilation system.

A fire resistant assembly is already known which has a shell in the form of a sleeve which is sealed in the wall to be passed through and in which there is mounted a f ire resistant cartridge having two shutters held in the open position counter to a spring by a fusible link which gives way at a temperature of about 700 so that the shutters move to the closed position and the system is then blocked.

The invention aims essentially to simplify the manufacture and assembly of this type of fire resistant assembly.

To this end, it proposes, in a first aspect a fire resistant cartridge for a ventilation system, designed to be mounted in the bore of a shell in the form of a sleeve, characterised in that the said cartridge includes for its assembly in the said shell snapping means adapted to cooperate with a bead projecting on the inside in the bore of the said shell.

It is therefore sufficient to push the cartridge into the bore of the shell until the cartridge comes to meet the bead of the shell, the assembly then being ended when the snapping means then retain the cartridge in the shell.

The operation to be performed for mounting the cartridge in the 2 shell is much more simple than in previous fire resistant assemblies, in which the cartridge is provided with two studs projecting outwards beyond its side wall and in which the shell is provided halfway along its bore with an annular recess connected on each side to axial grooves, the positioning of this previous cartridge in this previous shell necessitating firstly an angular positioning of the cartridge with respect to the shell so that each of the studs is opposite the end of one of the axial grooves, then the pushing of the cartridge into the shell until the studs are located in the annular recess, and then performing a slight rotation of the cartridge so that the studs are trapped in the recess.

According to characteristics which are preferred both for reasons of simplicity and ease of manufacture and use and for the reliability of the holding afforded, the said snapping means are formed by snapping lugs extending beyond the downstream end of the said cartridge in an axial direction, the said snapping lugs each having, from their free end, an insertion ramp inclined downstream and inwards and then a retaining wedge which is recessed with respect to the insertion ramp.

When the cartridge is mounted in the shell, the insertion ramps meet the annular bead and, by virtue of their inclination, cause the snapping lugs to flex inwards so that the insertion ramps are able to move beyond the bead, the snapping lugs then relax with their retaining wedge, which has just engaged on the bead opposite the cartridge, thereby affording the required resistance when the cartridge is withdrawn from the shell.

Preferably, the said retaining wedge has a first wall connected to the insertion ramp by its external end, and for example a second wall connected more or less at a right angle to the internal end of the said first wall.

These characteristics are favourable to the holding quality afforded by the snapping lugs, and in particular enable the force 3 needed to extract the cartridge from the shell to be sufficiently high.

Also preferably, for reasons of ease of fixing the snapping lugs on the cartridge, each of these lugs has a base fixed to a side wall of the said cartridge, the said retaining wedge being connected by its upstream end to the said base.

Furthermore, each said snapping lug advantageously has on the said base an index projecting outwards.

This index prevents the lug being able to pivot at its fixing for example by a rivet, with respect to the body of the cartridge.

According to other preferred characteristics, the cartridge has two semicircular shutters affording an open position in which they are parallel to the axis of a cartridge and a closed position in which they are transverse to the axis of the said cartridge, and has, in order to push the said shutters into the closed position, at least one spiral spring mounted about a pivot journal of the said shutters.

The use of this type of spring is particularly advantageous, notably as regards size, cost and performance in terms of closure force supplied.

The invention also relates, in a second aspect to the shell designed to contain the cartridge described previously, a shell which is characterised in that it is in the form of a sleeve and in that it has, for mounting the said cartridge, a bead projecting on the inside in its bore.

It will be observed that this shell is much simpler and cheaper to manufacture than the previous shell, whose axial grooves and recess call for relatively complex manufacturing operations.

According to preferred characteristics, the distance separating 4 the said bead from one of the ends of the said shell is substantially equal to the sum of the length of the said cartridge and the distance separating this bead from the other end of the shell.

It is thus possible to have the cartridge virtually centred with respect to the shell, and therefore level with the wall through which the shell passes.

According to other preferred characteristics, the said bead has a rectangular cross section.

Such a shape is simple and easy to obtain and is particularly suitable for cooperating with snapping lugs.

According to other preferred characteristics, for reasons of simplicity and ease of manufacture and in use for reasons of ease of connection to the ventilation system, the bore of the shell has a constant diameter.

The invention also relates, in a third aspect, to the f ire resistant assembly having a cartridge and a shell as described above.

Finally, the invention relates, in a fourth aspect, to a method for providing a ventilation system with a fire resistant assembly, which is characterised in that it includes the following steps:

a) sealing a shell in a centred position in a partition to be passed through; b) mounting a cartridge by snapping in the said shell; and c) connecting ventilation pipes to the said system at each end of the said shell.

The disclosure of the invention will now continue with the description of example embodiments, given hereinafter by way of non-limitative illustration, with reference to the accompanying drawings. In these:

- Figure 1 is a view in cross section of a fire resistant assembly according to the invention, one of the shutters of the cartridge being shown in the open position and the other in the closed position, this view being taken along a plane corresponding to the one marked I-I in Figure 2; - Figure 2 is a view in cross section of a variant of the fire resistant cartridge shown in Figure 1, along a plane corresponding to the one marked II-II in Figure 1; - Figures 3 and 4 are respectively a plan view and a side view of one of the snapping lugs which the said fire resistant cartridge has; and - Figure 5 is a view in cross section showing a fire resistant assembly in accordance with the invention in place in a ventilation system.

The f ire resistant assembly 1 shown in Figure 1 has a shell 2 and a fire resistant cartridge 3 mounted by snapping in this shell, where it is envisaged that air circulates from the end shown on the right to the one shown on the lef t, as indicated by an arrow.

The shell 2 is in the general form of a circular sleeve with an internal annular bead 4 projecting with respect to the side wall 5 of its bore.

This shell has a constant external diameter and an internal diameter which is also constant (it is the same on both sides of the bead 4), while its end surfaces 6 are straight.

The bead 4 has a rectangular cross section and is positioned in 6 such a way that the distance which separates it from the end which is shown on the left in Figure 1 (the downstream end) is approximately the same as the distance which separates the cartridge 3 from the end shown on L-he right (the upstream end). In other words, the distance separating the bead 4 from the upstream end is substantially equal to the sum of the length of the cartridge 3 and the distance separating the bead 4 from the downstream end.

The fire resistant cartridges shown respectively in Figure 1 and in Figures 2 and 5 are formed in exactly the same way, except that the body of the cartridge shown in Figure 1 is proportionally longer (with respect to its diameter) than the one shown in Figures 2 and 5. In order to simplify the description, no distinction will be made between these cartridges hereinafter.

The cartridge 3 has a body 7 and two shutters 8A and 8B which, during normal service, are held in an open position in which they are parallel to the axis of the body 7 so that the air circulating through the system is able to pass through the body 7 (position of the shutter 8A in the drawings), while beyond a certain temperature threshold (for example 70OC) they both take a closed position in which they are transverse with respect to the axis of the body 7 so that air, or indeed flames, is unable to pass through the cartridge 3 (position of shutter 8B in drawings).

The body 7 is in the general form of a circular tube, but having an external recess 9 at the downstream end and a contraction 10 at the upstream end. The external diameter of the body 7 is slightly less than that of the bore of the shell 2.

A lip joint 11 which provides a seal with respect to the internal wall 5 of the shell 2 is disposed in the recess 9. It is covered with a strip of material 12 which is intumescent, that is to say which expands when heated. A strip of intumescent material 13 is also provided in the contraction 10.

7 The shutters 8A and 8B are each semi-circular in shape and are each provided with two pivot brackets 14 at the respective ends of their straight edge, each bracket 14 being mounted on a journal 15 carried by the body 7.

The shutters 8A and 8B are in this case made of galvanized steel, and are lined on each face with a ceramic board 16, the board situated on the same side as the contraction 10 also being lined with a ceramic felt 17.

As can been seen in Figure 2, a spiral spring 18 is provided around each journal 15 to push each of the shutters 8A and 8B towards the closed position, the springs 18 each being held on the journal 15 by an axial retaining lug 19 riveted to the body 7.

In order to hold the shutters 8A and 8B in the open position, each of these shutters has a hook 20 disposed in such a manner that, when the shutters are in the open position, the hooks 20 are opposite each other and can each be hooked to a fusible link 21 which holds them mutually.

The fusible link 21, formed for example from brass combined with a tin alloy, is designed to give way above the aforementioned temperature threshold, so that, under the effect of the springs 18, the shutters 8A and 8B move to the closed position shown in Figure 1 for the shutter 8B.

In this position, each shutter is immobilised against the transverse wall of the body 7 which borders on the contraction 10 by means of a lug 22 made of elastic steel. This lug is riveted by its upstream end to the body 7 and has at the downstream end an inclined part which is situated on the path followed by the end of the corresponding shutter when it moves from the open position to the closed position, so that each blade 22 flexes when the shutter passes and then resumes its initial shape in which its end comes behind the shutter, which is thus 8 locked in the closed position.

A rod 23 oriented diametrically is fixed at each end on the part of the body 7 which forms the base of the contraction 10, the rod 23 being oriented parallel to the journals 15.

Two opposite snapping lugs 24 oriented in an overall axial direction are each riveted at one of their ends to the body 7 level with its part forming the bottom of the groove 9, each snapping lug 24 extending projectingly beyond the body 7 so as to be able to cooperate with the bead 4 which serves to retain the cartridge 3 in the shell 2 once it has been put in place.

The lugs 24 will now be described in greater detail, in conjunction with Figures 3 and 4.

These lugs are produced from folded elastic steel. They each have a flat base 25 having a riveting hole 26 and an index 27 engaged in an orifice in the body 7, forming an angle of approximately 1100 with the base 25, at one end of which it is connected; a retaining wedge 28 connected to the other end of the base 25, the retaining wedge having two walls 29 and 30 disposed at right angles, the wall 29 forming an angle of approximately 1600 with the base 25; and an insertion ramp 31 connected to the end of the wall 30, forming an angle of approximately 1300 with the latter.

All the aforementioned angles are measured from the side situated at the top of Figure 4 (inside of lug 24).

It can be seen, in general terms, that the insertion ramp 31 of each lug 24 slopes downstream and inwards, that the retaining wedge 28 is recessed with respect to the ramp 31 with its wall 30 which is connected to the ramp at its external end while it slopes downstream and inwards, that it is by its upstream end that the wedge 28 is connected to the base 25, and that the finger 27 is raised inwards.

9 The lug 24 is of substantially constant length (see Figure 3), its downstream end situated at the end of the ramp 31 being rounded while the edges of the base 25 are cut at an angle between the hole 26 and the finger 27, which is therefore narrower than the rest of the lug 24.

The index 27 serves to hold the lug 24 in an axial position, preventing it from slipping in rotation, which would prevent snapping in.

In order to position the cartridge 3 in the shell 2, the latter is grasped by the rod 23 and pushed into the bore in the shell 2 through the upstream end thereof (that which is furthest from the bead 4), with the snapping lugs 24 entering the bore first.

The cartridge 3 advances with friction due to cooperation between the lips of the joint 11 and the side wall 5, until the insertion ramps 31 of the lugs 24 meet the bead 4.

Because of the inclination of these ramps (downstream and inwards), cooperation between the ramps 31 and the bead 4 has the effect of making the blades 24 flex inwards as the pushing-in movement continues until the rounded part 32 between the ramp 31 and the wall 30 meets the internal wall 33 of the bead 4, the rounded part 32 then slides on the wall 33, and when the end thereof is reached, the lug 24 relaxes and the walls 30 and 29 of its wedge 28 come to be positioned respectively opposite the walls 34 and 33 of the bead 4. The position shown in Figure 1 then exists.

It can be seen that the cartridge 3 is then fixed in the shell 2, the abutment of the body 7 against the bead 4 preventing further pushing-in of the cartridge 3, while cooperation between the lugs 24 and the bead 4 exerts a retaining force which prevents the withdrawal of the cartridge 3, unless a significant force is exerted which allows the lugs 24 to flex in order to free them from the bead 4.

In practice, this force is sufficiently high to avoid any risk that the cartridge 3 should become detached while the ventilation system is in service, including when the shell 2 is installed vertically with the cartridge 3 below the bead 4.

of course, as for the placing of the cartridge 3 in the shell 2, this cartridge is extracted by gripping the rod 23.

The method by which a fire resistant assembly 1 is placed in a ventilation system will now be explained in conjunction with Figure 5.

In practice, first of all in the wall 35 through which the system is to pass, for example a concrete wall 110 mm thick, an opening 36 having a diameter greater than that of the shell 2, for example an opening measuring 40 mm more, is formed.

The shell 2 is then positioned in the centre of this opening, both axially and laterally, and then the shell 2 is sealed in the wall 35 by means of a peripheral pointing 37 produced with plaster.

The connection ef the shell 2 to the rest of the system is effected by a male sleeve with a rubber joint 38 which enables a standard pipe to be connected, for example a rigid spiral pipe 39 as shown on the left in Figure 5 or a semi-rigid pipe 40 as shown on the right.

of course, the pipe 40 and the sleeve 38 need to be removed before proceeding with the fitting and removal of the cartridge 3, notably for periodic checking and maintenance inspections.

In a variant of the cartridge 3, not shown, the lugs 24 are replaced by a similar lug, but one in which the angle between the base 25 and the wall 29 of the wedge 28 is 1800 (the wall 29 is in the same plane as the base 25), in which the width of the lug is constant, and in which the index 27 is replaced by an index formed by a narrow rounded portion of the base 25.

Numerous other variants are possible, and it should be stated in this regard that the invention is not limited to the examples described and depicted.

12

Claims

CLAIMS:

1. Fire resistant cartridge for a ventilation system, designed to be mounted in the bore of a shell in the form of a sleeve, wherein the said cartridge has for its mounting in the said shell snapping means adapted to cooperate with a bead projecting on the inside in the bore of the said shell.

2. Cartridge according to claim 1, wherein the said snapping means are formed by snapping lugs extending beyond the downstream end of the said cartridge in an axial direction, the said snapping lugs each having, from their free end, an insertion ramp sloping downstream and inwards and then a retaining wedge which is recessed with respect to the insertion ramp.

3. Cartridge according to claim 2, wherein the said retaining wedge has a first wall connected to the insertion ramp by its external end.

4. Cartridge according to claim 3, wherein the said retaining wedge has a second wall connected substantially at a right angle to the internal end of the said first wall.

5. Cartridge according to any one of claims 2 to 4, wherein each said snapping lug has a base f ixed to a side wall of the said cartridge, the said retaining wedge being connected by its upstream end to the said base.

6. Cartridge according to claim 5, wherein the said snapping lug has on the said base an index projecting outwards.

7. Cartridge according to claim 6, wherein the said index is narrower than the rest of the snapping lug.

8. Cartridge according to any one of claims 1 to 7, wherein the cartridge has two semi-circular shutters affording an open position in which they are parallel to the axis of the cartridge 13 and a closed position in which they are transverse to L-he axis of the said cartridge, and has, in order to push the said shutters towards the closed position, at least one spiral spring mounted about a pivot journal for the said shutters.

9. Shell for a ventilation system, designed to contain a fire resistant cartridge according to any one of claims 1 to 8, wherein the shell is in the form of a sleeve and in that it has for mounting the said cartridge a bead projecting on the inside in its bore.

10. Shell according to claim 9, wherein the distance separating the said bead from one of the ends of the said shell is substantially equal to the sum of the length of the said cartridge and the distance separating this bead from the other end of the shell.

11. Shell according to either one of claims 9 or 10, wherein the said bead has a rectangular cross section.

12. Shell according to any one of claims 9 to 11, wherein the bore of the shell has a constant diameter.

13. Fire resistant assembly, wherein the assembly has a cartridge according to any one of claims 1 to 8, and a shell according to any one of claims 9 to 12.

14. Method of providing a ventilation system with a fire resistant assembly, wherein the method includes the following steps:

a) sealing a shell according to any one of claims 9 to 12 in a centred position in a partition to be passed through; b) mounting a cartridge according to any one of claims 1 to 8 by snapping the cartridge in the said shell; and c) connecting ventilation pipes to the said system at each end of the said shell.

14 is. Method according to claim 14, wherein the said step c) includes the use of a male sleeve with a rubber joint to connect each said end of the said shell to a ventilation pipe.

16. A fire resistant cartridge for a ventilation system substantially as hereinbefore described with reference to the accompanying drawings.

17. A shell for a ventilation system substantially as hereinbefore described with reference to the accompanying drawings.

18. A fire resistant assembly for a ventilation system substantially as hereinbefore described with reference to the accompanying drawings.

19. A method of providing a ventilation system substantially as hereinbefore described with reference to the accompanying drawings.