GB1567895A

GB1567895A - Operating head for a fire extinguisher

Info

Publication number: GB1567895A
Application number: GB1642978A
Authority: GB
Original assignee: Glover & Co Ltd T
Current assignee: Glover & Co Ltd T
Priority date: 1978-04-26
Filing date: 1978-04-26
Publication date: 1980-05-21

Description

(54) AN OPERATING HEAD FOR A FIRE EXTINGUISHER (71) We, THOMAS GLOVER & CO.

LIMITED, a British Company of Hathershaw, Oldham OL8 3DX, England, do hereby declare the invention for which we pray that a Patent may be granted to us, and tile method by which It is to be performed to be particularly described in and by the following statement: The present invention relates to an operating head for a fire extinguisher and a fire extinguisher incorporating such a head.

Usually, fire extinguishers are put into operation by piercing the seal of an auxiliary pressure container or gas cartridge mounted m the extinguisher so that the pressure of the released gas serves to expel the extinguish ant medium therefrom.

Conventional extinguishers either have discharge outlets or nozzles which are always open, so that the single action of piercing the seal of the gas cartridge serves to pressurise the extinguisher and discharge the contents, or alternatively have discharge outlets or nozzles which include a valve for controlling the discharge. The latter type of extinguishers generally requires a second action to open the valve to permit discharge of the contents.

The object of the present invention is to provide an operating head for a fire extinguisher in which one action by an operator both activates the extinguisher and opens a valve to permit discharge of the extinguishant medium.

According to a first aspect of the present invention there is provided an operating head for a fire extinguisher defining a passageway for flow of a fire extinguishant medium therethrough, and comprising a valve which in a first position obturates said passageway which is movable to a second position in which the passageway is open, and an operating mechanism in which a first spindle is movable whereby the fire extinguisher may be primed to release a fire extinguishant medium and whereby the valve is constrained to move from the first position to the second position to permit flow of the extinguishant medium through the passageway, the valve being also movable from the first position to the second position independently of the movement of the first spindle under the influence of pressure acting thereon from within the operating head whereby the valve is capable of serving as a safety pressure relief valve for the fire extinguisher.

According to a second aspect of the present invention there is provided a fire extinguisher incorporating operating head according to the first aspect of the present invention.

The present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a sectional view of part of a fire extinguisher for use with a liquid extinguishant medium and incorporating an operating head according to the present invention; and Figure 2 is a sectional view of another fire extinguisher for use with a dry powdered or particulate extinguishant medium and incorporating an operating head similar to that shown in Figure 1.

Referring first to Figure 1, the fire extinguisher comprises a container 1 holding a liquid extinguishant medium 2 and an operating head 2 which closes the container 1. The head 3 is screw-fitted into a neck 4 of the container 1 and seals against a washer 5.

The extinguisher additionally comprises a sealed gas cartridge 6 which contains a propellant fluid such as pressurised carbon dioxide and which is fitted into a bore 7 of the head 3. The cartridge 6 is sealed by means of a diaphragm 8 which, to activate the extinguisher, is pierced by a pin 9 as is described below.

The operating head 3, which may be made of a moulded plastics material, defines two adjoining bores 10, 11 which together define a passageway for flow of the extinguishant medium 2 therethrough during use of the extinguisher. The bore 10 has an end of a discharge tube 12 located therein, which tube 12 is open at the bottom of the container 1 to permit the liquid cxtinguishant medium 2 to be forced upwards therethrough under pressure during use. Fitted into the bore 11 is an insert 13 which at one end forms a seating 14 for a valve 15 obturating the bore 11 and at the other end forms a discharge nozzle 16 to which a flexible outlet hose 17 is fitted for directing the extinguishant medium where desired.

The valve 15 is attached by a screw 18 to a spindle 19 which can slide in the bore 11 against the resistance of a spring biassing means 20. The spring 20 is of a predetermined strength and acts between a blind end 21 of the bore 11 and an end of the spindle 19. To prevent passage of the extinguishant medium towards the blind end 22 instead of into the nozzle 16 during use, a sealing ring 23 is fitted into an annular groove of the spindle 19.

The valve spindle 19 additionally is provided with an aperture 24 through which a second spindle 25 passes into the bore 7 of the head 3. The spindle 25 passes with clearance through the aperture 24 which permits the valve 15 to open automatically against the resistance of the spring 20 if the pressure in the discharge tube 12 and the bore 11 exceeds a predetermined pressure corresponding to the strength of the spring 20.

Thus, the valve 15 acts as a safety pressure relief valve if the extinguisher is overpressurised to a dangerous degree in addition to controlling outflow of the extinguishant medium during normal use of the extinguisher as is described below. Overpressurization of the extinguisher could occur if the container 1 is over-filled or if an incorrect gas cartridge 6 is fitted.

The spindle 25 is slidably mounted within the bore 7 and its travel is limited by a pin 26 which is fixed to the operating head 3 and which can travel in a slot 27 formed in the spindle 25. At its lower end the spindle 25 mounts the pin 9 and is fitted with a sealing ring 28 which prevents flow of the extinguishant medium or propellant gas upwardly into the bore 7 towards the bore 11. The sealing ring 28 slides against the surface of an insert 29 which is screw-fitted into the bore 7 and into which the gas cartridge 6 is screwed.

The pin 9 comprises a tube with a longitudinal slot whereby on piercing of the diaphragm 8 of the gas cartridge 6, the propellant gas can escape therefrom and pass through holes 30 formed into the insert 29 into an ullage space 31 above the extinguishant medium contents 2.

At the upper end of the spindle 25 is an enlarged head 32 against which can bear a lever 33 pivotally mounted to a fixed part of the operating head 3 as at 34. The lever 33 can pivot towards a fixed carrying handle 35 and forms therewith a squeeze-grip whereby the extinguisher can be actuated and operated by one hand of an operator. Inadvertant movement of the lever 33 towards the handle 35 is prevented by an obstructing means formed by a clip 36 which is of bifurcate construction and fits partially around the spindle 25 beneath the enlarged head 32 to prevent movement of the spindle 25 in the bore 7 and thereby movement of the lever 33. The clip 36 is additionally attached to the operating head by a frangible wire 37 which passes through a hole 38 in the handle 35.

The spindle 25 is additionally provided with a formation 39 of wedge-shaped crosssection which is complementary to a second wedge-shape 40 formed in an edge defining the aperture 24 af the valve spindle 19. Thus, when the spindle 25 slides downwards in the bore 7, the formation 39 engages the matching formation 40 and the valve spindle 19 is forced to slide in the bore 11 against the resistance of the spring 20 to lift the valve 15 off the seating 14. In this way only a single action is required on the part of an operator both to activate the extinguisher and permit extinguishant discharge.

To operate the fire extinguisher, therefore, the safety clip 36 is removed breaking the frangible wire 37 and the lever 33 is pivoted towards the handle 35 by a squeezing action. The lever 33 bears against the spindle 25 which is thereby forced to slide down the bore 7 until the pin 9 pierces the diaphragm 8 of the gas cartridge 6. Additionally, movement of the spindle 25 into the bore 7 causes the valve 15 to open as described above. The propellant gas escapes from the cartridge 6 via the tubular pin 9 and passes through the holes 30 into the ullage space 31. Pressure is thus built up in the space 31 and when a predetermined pressure is reached the liquid extinguishant medium is forced to flow through the discharge tube 12 and into the bores 10,11 whence it passes out of the extinguisher via the valve 15 and discharge nozzle 16 to which is connected the outlet hose 17 for directing the extinguishant flow.

Figure 2 shows an extinguisher for use with a dry powdered or particulate extinguishant medium 41 but with an operating head 3 identical to that described above with reference to Figure 1, similar elements of the head 3 being indicated by the same reference numerals. The extinguisher of Figure 2 is modified by the provision of a tube 42 which is screw-fitted to a depending skirt 43 of the operating head 3. The tube 42 encloses the gas cartridge 6 and the discharge tube 12 and has a member 44 attached to its lower end to provide a neck 45 through which passes the end of the discharge tube 12. A series of radial holes 46 are formed in the member 44, which holes are normally covered by a band of elastomeric material 47 to prevent ingress of the extinguishant medium 41 into the tube 42.

Additionally, the extinguisher of Figure 2 is modified by the provision of a frangible diaphragm 48 held at the end of the outlet hose 17. The diaphragm 48 is held in position by a washer 49 and an insert 50 screw-fitted into the end of the hose 17, which insert 50 clamps the diaphragm in place to seal the end of thc hose 17.

The provision of such a diaphragm in a fire extinguisher is the subject of our co-pending United Kingdom Patent Applicatlon No.

15977/78 (Serial No. 1568467) filed 22nd April, 1978.

In use, the operating head 3 acts as previously described with reference to Figure 1, However, the propellant gas released from the gas cartridge 6 is directed downwards to the bottom of the container 1 by the tube 42.

The pressure of the gas in the tube 42 is sufficient to stretch the clastomeric material 47 and permit the gas to pass through the radial holes 46 into the container l where it fluidises the powdered or particulate extinguishant medium 41. When a working pressure has built up within the extinguisher and the extinguishant medium has passed upwards through the discharge tube 12 and down the outlet hose 17, the pressure is sufficient to break the frangible diaphragm 48 and the contents of the extinguisher is expelled. It will be appreciated that the bursting characteristics of the diaphragm are chosen to be such that the diaphragm is broken at substantially the same pressure as the working pressure of the extinguishant medium.In this way, discharge does not commence until at least a minimum working pressure has been reached within the extinguisher irrespective of the rate of release of the propellant gas from the cartridge 6.

As previously described, the clip 36 is normally attached to the operating head 3 by a frangible wire 37. Thus, when the extinguisher as described with reference to either Figure 1 or Figure 2 has been used or tampered with, the wire 37 is broken which indicates that the extinguisher may be empty.

However, a more positive indication of extinguisher use may be incorporated in the operating head 3. Such an indication comprises an indicator 51 which is normally concealed within the channel section of the lever 33 which is hollow. The indicator 51 is pivotally mounted to the operating head 3 at 34 and is provided with an aperture 52. One edge 53 defining the aperture 52 rests against the enlarged head 32 of the spindle 25.

In operation of the operating head 3, movement of the spindle 25 into the bore 7 by the lever 33 carries with it the indicator 51. When the spindle 25 has been depressed a predetermined distance, the edge 53 of the aperture 52 clears the head 32 and the indicator 51 is permitted to fall under gravity onto the upper surface of the operating head 3 into a clearly visible position. Once having fallen into such a position, the indicator S l is unable to be concealed once more within the hollow lever 33 because the edge 53 is unable to pass back over the enlarged head 32 of the spindle 25.

It is possible to reset the indicator 51 after use of the extinguisher by inserting a tool under the indicator 51 and fully depressing the lever 33. The indicator 51 can then be lifted in contact with the interior of the lever 33, the edge 53 of the aperture 52 being then able to clear the head 32, and ride back to its initial position. It will be appreciated that such a resetting operation will be carried out when the extinguisher is refilled for future use.

To provide an effective indication of use, the indicator 51 is preferably of a bright colour and marked with an inscription such as "USED" or "EMPTY".

The provision of such an indicator 51 as described above in a fire extinguisher operating mechanism is the subject of our copending United Kingdom Patent Application No. 33262/77 (Serial No. 1566815) filed 9th August 1977.

WHAT WE CLAIM IS: 1. An operating head for a fire extinguisher defining a passageway for flow of a fire extinguishant medium therethrough, and comprising a valve which in a first position obturates said passageway and which is move able to a second position in which the passageway is open and an operating mechanism in which a first spindle is movable whereby the fire extinguisher may be primed to release a fire extinguishant medium and whereby the valve is constrained to move from the first position to the second position to permit flow of the extinguishant medium through the passageway, the valve being also movable from the first position to the second position independently of the movement of the first spindle under the influence of pressure acting thereon from within the operating head whereby the valve is capable of serving as a safety pressure relief valve for the fire extinguisher.

2. An operating head as claimed in claim 1, in which the valve moves from the first position to the second position against the resistance of a biassing means tending to retain the valve in the first position.

3. An operating head as claimed in claim 1 or 2, in which the valve is joined to a second spindle cooperable with the first spindle whereby movement of the first spindle

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

Claims

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

provide a neck 45 through which passes the end of the discharge tube 12. A series of radial holes 46 are formed in the member 44, which holes are normally covered by a band of elastomeric material 47 to prevent ingress of the extinguishant medium 41 into the tube 42.

Additionally, the extinguisher of Figure 2 is modified by the provision of a frangible diaphragm 48 held at the end of the outlet hose 17. The diaphragm 48 is held in position by a washer 49 and an insert 50 screw-fitted into the end of the hose 17, which insert 50 clamps the diaphragm in place to seal the end of thc hose 17.

The provision of such a diaphragm in a fire extinguisher is the subject of our co-pending United Kingdom Patent Applicatlon No.

15977/78 (Serial No. 1568467) filed 22nd April, 1978.

In use, the operating head 3 acts as previously described with reference to Figure 1, However, the propellant gas released from the gas cartridge 6 is directed downwards to the bottom of the container 1 by the tube 42.

The pressure of the gas in the tube 42 is sufficient to stretch the clastomeric material 47 and permit the gas to pass through the radial holes 46 into the container l where it fluidises the powdered or particulate extinguishant medium 41. When a working pressure has built up within the extinguisher and the extinguishant medium has passed upwards through the discharge tube 12 and down the outlet hose 17, the pressure is sufficient to break the frangible diaphragm 48 and the contents of the extinguisher is expelled. It will be appreciated that the bursting characteristics of the diaphragm are chosen to be such that the diaphragm is broken at substantially the same pressure as the working pressure of the extinguishant medium.In this way, discharge does not commence until at least a minimum working pressure has been reached within the extinguisher irrespective of the rate of release of the propellant gas from the cartridge 6.

As previously described, the clip 36 is normally attached to the operating head 3 by a frangible wire 37. Thus, when the extinguisher as described with reference to either Figure 1 or Figure 2 has been used or tampered with, the wire 37 is broken which indicates that the extinguisher may be empty.

However, a more positive indication of extinguisher use may be incorporated in the operating head 3. Such an indication comprises an indicator 51 which is normally concealed within the channel section of the lever 33 which is hollow. The indicator 51 is pivotally mounted to the operating head 3 at 34 and is provided with an aperture 52. One edge 53 defining the aperture 52 rests against the enlarged head 32 of the spindle 25.

In operation of the operating head 3, movement of the spindle 25 into the bore 7 by the lever 33 carries with it the indicator 51. When the spindle 25 has been depressed a predetermined distance, the edge 53 of the aperture 52 clears the head 32 and the indicator 51 is permitted to fall under gravity onto the upper surface of the operating head 3 into a clearly visible position. Once having fallen into such a position, the indicator S l is unable to be concealed once more within the hollow lever 33 because the edge 53 is unable to pass back over the enlarged head 32 of the spindle 25.

It is possible to reset the indicator 51 after use of the extinguisher by inserting a tool under the indicator 51 and fully depressing the lever 33. The indicator 51 can then be lifted in contact with the interior of the lever 33, the edge 53 of the aperture 52 being then able to clear the head 32, and ride back to its initial position. It will be appreciated that such a resetting operation will be carried out when the extinguisher is refilled for future use.

To provide an effective indication of use, the indicator 51 is preferably of a bright colour and marked with an inscription such as "USED" or "EMPTY".

The provision of such an indicator 51 as described above in a fire extinguisher operating mechanism is the subject of our copending United Kingdom Patent Application No. 33262/77 (Serial No. 1566815) filed 9th August 1977.

WHAT WE CLAIM IS: 1. An operating head for a fire extinguisher defining a passageway for flow of a fire extinguishant medium therethrough, and comprising a valve which in a first position obturates said passageway and which is move able to a second position in which the passageway is open and an operating mechanism in which a first spindle is movable whereby the fire extinguisher may be primed to release a fire extinguishant medium and whereby the valve is constrained to move from the first position to the second position to permit flow of the extinguishant medium through the passageway, the valve being also movable from the first position to the second position independently of the movement of the first spindle under the influence of pressure acting thereon from within the operating head whereby the valve is capable of serving as a safety pressure relief valve for the fire extinguisher.
2. An operating head as claimed in claim 1, in which the valve moves from the first position to the second position against the resistance of a biassing means tending to retain the valve in the first position.
3. An operating head as claimed in claim 1 or 2, in which the valve is joined to a second spindle cooperable with the first spindle whereby movement of the first spindle

causes movement of the second spindle to open the valve.
4. An operating head as claimed in claim 3, in which the first and second spindles are provided with complementary formations which on movement of the first spindle engage and bear one against the other to cause movement of the second spindle.
5. An operating head as claimed in claim 4, in which the formations are of wedgeshaped cross-section.
6. An operating head as claimed in any of claims 3 to 5, in which the first spindle passes through an aperture in the second spindle.
7. An operating head as claimed in any of claims 1 to 6, in which movement of the first spindle is limited by means of a pin slidable in a slot of predetermined length.
8. An operating head as claimed in any of claims 1 to 7, in which the first spindle mounts a pin for piercing a diaphragm of a cartridge containing a propellant fluid for activating the fire extinguisher.
9. An operating head as claimed in claim 8, in which the piercing pin is a tube provided with a longitudinal slot therein.
10. An operating head as claimed in any of claims 1 to 9, in which the operating mechanism additionally comprises a lever mounted on a fixed portion of the operating head and pivotable to bear against an end of the first spindle to move same.
11. An operating head as claimed in claim 10, which the lever is pivotable towards a fixed handle to provide a squeeze-grip operating mechanism.
12. An operating head as claimed in claim 10 or 11, in which a removable obstructing means engages said end of the first spindle to prevent inadvertant movement of said spindle.
13 An operating head as claimed in claim 12, in which the obstructing means is linked to a fixed portion of the operating head by a frangible wire, removable of the obstructing means causing breakage of the wire.
14. An operating head as claimed in any of claims 10 to 13, in which the lever is hollow and normally conceals an indicator which is retained in a first position by abutment against said end of the first spindle, movement of the first spindle permitting the indicator to move into a visible second position.
15. An operating head as claimed in claim 14, in which the indicator is pivotally mounted on said fixed portion of the operating head and is provided with an aperture whereby, on movement of the first spindle.

the indicator pivots and is carried by the lever to a position wherein an edge of the indicator defining the aperture clears said end of the spindle to permit the indicator to fall under gravity into the visible second position.
16. An operating head as claimed in any of claims 1 to 15, in which the passageway forms at least partially an outlet conduit for the extinguishant medium from the fire extinguisher.
17. An operating head as claimed in claim 16, in which the outlet conduit is sealed by a frangible diaphragm of predetermined bursting characteristics whereby on attainment of a predetermined pressure within the outlet conduit the diaphragm bursts to permit flow of the extinguishant medium through the passageway.
18. An operating head for a fire extinguisher substantially as hereinbefore described with reference to Figure 1 or 2 of the accompanying drawings.
19. A fire extinguisher incorporating an operating head as claimed in any of claims 1 to 18.
20. A fire extinguisher incorporating an operating head substantially as hereinbefore described with reference to Figure 1 or 2 of the accompanying drawings