GB2239395A

GB2239395A - Triggering element

Info

Publication number: GB2239395A
Application number: GB9025621A
Authority: GB
Inventors: Nikolaus Grainer; Heinz Heider
Original assignee: Total Walther Feuerschutz GmbH; Total Feuerschutz GmbH
Current assignee: Total Walther Feuerschutz GmbH; Total Feuerschutz GmbH
Priority date: 1989-12-07
Filing date: 1990-11-26
Publication date: 1991-07-03
Anticipated expiration: 2010-11-26
Also published as: GB9025621D0; CH682219A5; GB2239395B; DE3940453C1

Abstract

The invention relates to a frangible triggering element 1 for triggering a fire protection installation which comprises a chamber formed by a prefabricated cylindrical tube 2 onto the ends of which end pieces are melted, the specific shape of the tapered end and the thickness of the walls being specified. <IMAGE>

Description

1 -I- TRIGGERING ELEMENT This invention relates to a triggering element

for the thermal and/or electrical triggering of a fire protection installation in particular for sprinkler installations, wherein the triggering element is preferably made of glass and is filled to bursting with a liquid (herein referred to as the "bursting liquid").

A triggering element of this type normally maintains the valve of a sprinkler head closed; however, in the event of fire the bursting liquid in the triggering element expands in response either to the increase in temperature or to an electrical impulse and bursts the element thereby opening the valve in the sprinkler head. The delay in bursting of the element is hereafter referred to as the "bursting time". In principle, the triggering element has two tasks to fulfil. Firstly, it must absorb the clamping forces imposed by the sprinkler housing po.as to keep the valve closed at all times when there is no fire.

Secondly, it must explode rapidly in the event of fire so that the extinguishing process can begin as quickly as possible. In this connection, it is necessary for the sprinkler heads to remain in working order for decades.

This triggering element is an improvement on the subject matter of British Patent Application No.

2206489 and comprises a chamber defined by a cylindrical intermediate part with a thin wall thickness, and two ends of relatively thicker wall thickness which extend beyond the chamber, one end being rounded off on the outside and the other end tapering in the axial direction and shaped so as to give the chamber a funnel-shaped end and having a filling hole, which after filling with the bursting liquid is closed by melting. The triggering element is formed from a prefabricated cylindrical tube, which forms the intermediate part, onto both ends of which an end piece Is melted. The triggering element has a cylindrical outer face over substantially its whole length and the end forming a funnel-shaped end to the chamber has on the outer side a planar surface or shoulder which forms an angle a to the longitudinal axis of the triggering element of between 30 and 4Y, and the other end is shaped so as to provide the chamber with a substantially planar end.

The underlying object of the invention is to create a triggering element which can be manufactured by simple means without great expense, without effecting the requirements for sufficient stability during installation and for a quick bursting time in the case'of a fire.

This object is solved by the present invention which provides a triggering element of the type described above, the intermediate part of which has an outer diameter no greater than 5mm and a wall thickness of between 0.8 and 0.5mm with a tolerance of 0.02 to 0.03mm, and in which the end that tapers has a wall thickness of 1.5 to 2.0 times the wall thickness of the intermediate part, in which the wall thickness of that end is measured on a line lying at right angles to the planar surface or shoulder and originating from a point on the inner surface of the triggering member, which point lies on a cross section of the triggering element which has an inner diameter of between 60 and 85 of the inner diameter of the cylindrical intermediate part.

A further inventive feature is that the cylindrical intermediate part of the triggering element has a length of between 18 to 22mm with an overall length of the triggering element being between 25 and 29mm.

With the characterising features of the present 1 invention a triggering element can be constructed with -thin walls which in use are only acted upon by compressive forces. The construction of the ends has the effect that the forces are introduced, without damaging effects for the thin walled intermediate part, Into the end with the filling hole.

An exemplary embodiment is represented in the drawing and is described more closely in the' following.

The triggering element 1 consists of a cylindrical intermediate part 2 with very thin wall thicknesses 3 and an upper end 4 and a lower end 5, which are comparatively thickened internally. The lower end tapers downwards-in the axial direction and has a central filling hole 6. After filling of the triggering element with the bursting liquid 7 the lower part 8 is closed by melting. The lower end 5 has in its outer part a shoulder 9, which forms an angle to the longitudinal axis 10 of the triggering element of between 30 and 45'. The upper end 4 which is externally rounded-off is shaped so as to provide the interior of the triggering element with a flat, even, planar base 11. The upper end 4 of the triggering element 1 having the outer diameter 17 is reinforced with a cylindrical part 12, the length 13 of which corresponds to the diameter 17. In this case the forces emanating from a sprinkler housing in which the triggering element is used can be introduced into the lower end 5 without damaging the cylindrical intermediate part 4.

The wall thickness 18 of the lower end 5 is measured on the line 18, which lies at right angles to the line of the planar surface of shoulder 9 and emanates from a point 20 on the inner surface, which point lies on a cross section 21 of the triggering element, which has an inner diameter of between 60 and 80 of the inner diameter 22 of the cylindrical intermediate part. The length 23 of the intermediate k part 2 amounts to between 18 and 22mm with the overall length 24 of the triggering element being between 25 and 29mm.

Claims

1. A triggering element for thermal and/or electrical triggering of a fire protection installation in particular for a sprinkler installation, wherein the triggering element is filled to bursting with a liquid, and comprises a chamber defined by a cylindrical intermediate part with a thin wall thickness and two ends of relatively thicker wall thickness which extend beyond the chamber, one end being rounded off on the outside and the other end tapering in the axial direction and providing the chamber with a funnelshaped end and having a filling hole, which after filling with the bursting liquid is closed by melting, which triggering element is formed from a prefabricated cylindrical tube, which forms the intermediate part, onto both ends of which an end piece is melted, the triggering element having a cylindrical outer face substantially over its whole length, and the end of the triggering element forming a funnel-shaped end to the chamber has on its outer side a planar surface or shoulder, which forms an angle a to the longitudinal axis of the triggering element of between 30 and 400, and the other end is shaped so as to provide the chamber with a substantially planar end, wherein the intermediate part has an outer diameter of no greater than 5mm and has a wall thickness of between 0.8 and 0.5mm with a tolerance of 0.02 to 0. 03mm and wherein the tapered end has a wall thickness of 1.5 to 2.0 times the wall thickness of the intermediate part, and in which the wall thicknss of the tapered end is measured on a line lying at right angles to the planar surface of the shoulder and emanating from a point on the inner surface of the triggering element, which point lies on a cross section of the triggering element which has an inner diameter of 60 to 85% of the inner diameter of the cylindrical intermediate part.

2. A trigger element according to claim 1, wherein the cylindrical intermediate part has a longitudinal length of between 18 and 22mm with the overall longitudinal length of the triggering element 5 being between 25 and 29mm.

3. A triggering element substantially as hereinbefore described with reference to the accompanying drawing.

PubUshed 1991 at 7he Patent. State House. 66171 HWh Holborn, London WC1R47P. Further copies my be obtained from Sales Branch. Unit 6. Nine Mile Point. Cwmfchnfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques lid. St Mary Cray. Kent.