US3860176A

US3860176A - Fire-fighting branch pipe nozzles

Info

Publication number: US3860176A
Application number: US460552A
Authority: US
Inventors: John L Evans
Original assignee: Chubb Fire Security Ltd
Current assignee: Chubb Fire Ltd
Priority date: 1973-04-12
Filing date: 1974-04-12
Publication date: 1975-01-14
Anticipated expiration: 1992-01-14
Also published as: CA1003002A; FR2225215B3; ZA742200B; DE2417514A1; GB1442203A; FR2225215A1; AU6772374A

Abstract

A fire-fighting branch pipe nozzle for discharging fire extinguishing liquid, such as foam compound, is provided with a shut-off valve having a valve member which is moveable from an open position to a closed position by means of a piston acted upon by the fire extinguishing liquid under pressure supplied to the nozzle. The supply of liquid to the piston is controlled by a manually-operable pilot valve and the movement of the valve member from the open position to the closed position and preferably also from the closed position to the open position is controlled by a dash-pot which limits the rate of movement of the valve member. The dash-pot is preferably formed by the piston and a cylinder in which the piston is contained, the cylinder having restricted openings for the discharge of liquid supplied to it on both sides of the piston to limit the rate of escape of liquid from the cylinder as the piston moves and thus also to limit the rate of movement of the piston.

Description

United States Patent [191 Evans FIRE-FIGHTING BRANCH PIPE NOZZLES [75] Inventor: John L. Evans, Sunbury-on-Thames,

England Chubb Fire Security Limited, Sunbury-on-Thames, Middlesex, England Apr. 12, 1974 Appl. No.: 460,552

[73] Assignee:

[22] Filed:

[30] Foreign Application Priority Data Jan. 14, 1975 Primary Examiner-Lloyd L. King Assistant ExaminerMichael Mar Attorney, Agent, or Firm-Brisebois & Kruger [57] ABSTRACT A fire-fighting branch pipe nozzle for discharging fire extinguishing liquid, such as foam compound, is provided with a shut-off valve having a valve member which is moveable from an open position to a closed position by means of a piston acted upon by the tire extinguishing liquid under pressure supplied to the nozzle. The supply of liquid to the piston is controlled by a manually-operable pilot valve and the movement of the valve member from the open position to the closed position and preferably also from the closed position to the open position is controlled by a dashpot which limits the rate of movement of the valve member. The dash-pot is preferably formed by the piston and a cylinder in which the piston is contained,

[56] R fe Cited the cylinder having restricted openings for the dis- UNITED STATES PATENTS charge of liquid supplied to it on both sides of the piston to limit the rate of escape of liquid from the cylinder as the piston moves and thus also to limit the rate 315541452 1/1971 Davidson et al.:::...........:.... 239/456 of movement of the 11 Claims, 4 Drawing Figures FIRE-FIGHTING BRANCH PIPE NOZZLES It is desirable for a fireman in charge of a fire-fighting branch pipe to be able to control the flow of fire extinguishing liquid, such as water or foam, from the nozzle at the end of the pipe. If the flow of liquid through a branch pipe is shut down too suddenly, the resulting pressure surge in the hose leading to the branch pipe may even cause the hose to burst.

So that it is impossible to shut down the flow too rapidly, it is customary to provide some form of screwdown valve to control the discharge of liquid from a branch pipe nozzle and, in the case of a water nozzle, the valve may also be arranged to alter the discharge pattern from a spray to a jet as it is operated. This form of valve is safe, but it is necessarily slow in operation and it is difficult for firemen to operate and at the same time maintain proper directional control of the branch pipe.

The object of the present invention is to provide a fire-fighting branch pipe nozzle with a shut-off valve which is operable more rapidly and very much more easily than the customary form of screw-down valve and yet still avoids the production of excessive pressure surges as it is closed.

To this end, according to this invention, a firefighting branch pipe nozzle for discharging fire extinguishing liquid is provided with a shut-off valve having a valve member which is movable between closed and open positions under the control of a manuallyoperable pilot valve having a passage leading to it from upstream of the valve member so that it is, in use, supplied with the fire extinguishing liquid under pressure, and a dash-pot is provided to limit the rate of movement of the valve member from the open position to the closed position.

With this arrangement, the closing of the shut-off valve is initiated merely by operating the pilot valve and the movement of the valve member is then brought about by the pressure of the fire extinguishing liquid upstream of the valve member, but the speed of movement of the valve member to the closed position is limited by the dash-pot to such an extent that the pressure surge is kept within required limits.

If the flow through a branch pipe is turned on too suddenly, the sudden reaction from the jet of liquid issuing from the nozzle may make the branch pipe difficult to manage. Preferably therefore the dash-pot in the fire-fighting branch pipe nozzle in accordance with the invention is double-acting and also limits the rate of movement of the valve member from the closed position to the open position in order to restrict the rate of increase of the jet reaction.

The dash-pot may be entirely sealed from the passage through the valve, and in this case it may be permanently filled with a liquid such as oil which moves from one side of a dash-pot piston to the other as the valve member moves to or from the closed position. Preferably, however, the dash-pot comprises a cylinder with a piston the space on one side of which communicates with a passage leading from the pilot valve so that when the pilot valve is opened this space is supplied with the tire extinguishing liquid which moves the piston and with it the valve member. In this case the piston and the cylinder have the dual function of providing the dashpot action and also of acting as a hydraulic working piston and cylinder to move the valve member.

When the dash-pot is arranged in this way, preferably the pilot valve is connected to the space on the downstream side of the piston so that when fire extinguishing liquid under pressure is admitted to the space through the pilot valve, this moves the piston and the valve member in an upstream direction and this is preferably towards the closed position. The space within the cylinder which communicates with the pilot valve preferably also has a restricted venting passage to provide a dashpot action to control the movement of the valve member from the closed to the open position. With this arrangement, when the pilot valve is closed, the valve member is moved from the closed position to the open position in a downstream direction by the pressure of the fire extinguishing liquid acting on an upstream surface of the member and the speed of this movement is restricted by the dash-pot action produced by the escape of the liquid from the space within the cylinder through the restricted venting passage.

Preferably also with the construction just described, the space within the cylinder on the upstream side of the piston, that is the side of the piston remote from that having the space in communication with the pilot valve, is closed except for a restricted passage which leads to the main flow passage for the fire extinguishing liquid through the shut-off valve. Thus, when the valve member is moved upstream towards the closed position by the admission of fire extinguishing liquid into the cylinder through the pilot valve, liquid is expelled at a limited rate from the chamber on the upstream side of the piston and this slow expulsion gives rise to the necessary dash-pot action in the upstream direction to provide slow closure of the shut-off valve. When the valve member is in the closed position and the pilot valve is also closed, the pressure of the fire extinguishing liquid on the valve member moves the valve member downstream to its open position at a limited speed as already described.

Preferably the valve member is tubular and itself forms a discharge jet tube through which the main flow of fire extinguishing liquid through the nozzle takes place. An annular flange, which forms the piston, projects from the jet tube into the cylinder. A closure member is fixed in position in the main flow passage through the valve just upstream of the jet tube. This closure member is supported by a spider so that when the valve is opened, the liquid can flow past the closure member and then through the jet tube whence it is discharged from the nozzle. When the jet tube is moved upstream into its closed position, however, its upstream end comes into engagement with the closure member which closes the jet tube and thus shuts the valve.

The pilot valve may be trigger operated and may include a closure member in the form of a plunger which is spring-loaded to an open position, but preferably the pilot valve includes a closure member which is controlled by means of a twist-grip on a handle for holding the branch pipe nozzle. In this case again the pilot valve closure member is preferably spring-loaded to an open position. This is a fail-safe arrangement because if the nozzle gets out of control, so that the fireman lets go of the handle, the pilot valve is then moved by its spring to its open position so that fire-fighting liquidunder pressure flows through the pilot valve and moves the valve member to its closed position to shut off the flow through the nozzle.

An example of a fire-fighting foam branch pipe incorporating a nozzle constructed in accordance with the invention is illustrated in the accompanying drawings, in whichr FIG. 1 is an axial section through the upstream part of the branch pipe;

FIG. 2 is a cross-section as seen in the direction of the arrows on the line II-II in FIG. 1;

FIG. 3 is a side elevation of the foam outlet end of the branch pipe; and,

FIG. 4 is a plan of the part of the branch pipe shown in FIG. 3. The branch pipe comprises a tubular body 1 having at its upstream end, which is the left hand end as shown in FIG. 1 of the drawings, a male coupling spigot 2 to allow it to be coupled to a female hose coupling. A ring 3 is fixed to the downstream end of the body 1 by three angularly spaced webs one of which is shown in FIG. 1 at 4. There are thus three slots 5 which form air intakes between the body 1 and the ring 3. A foam-making tube 6, only part of which is shown, is fixed to the ring 3 by screws 7 and may lead to a foam outlet assembly, which isconstructed as described in our British Specification No. 730,046 and includes pivotally mounted guide blades which can be adjusted to alter the spread of the stream of foam issuing from the assembly. Preferably, however the tube 6 leads an outlet as shown in FIGS. 3 and 4 of the drawings.

To open or shut-off the flow of fluid into the tube 6, the valve body 1 contains a fixed valve closure member 18 supported by a spider l9 and a tubular valve member 20. The valve member 20 has a radially outwardly projecting flange which forms an annular piston 21 within an annular cylinder 22. The piston 21 is sealed to the wall of the cylinder 22 by an O-ring 23. The left hand end of the cylinder 22 is closed by a wall 24 carrying an O-ring 25 which seals against the outside of the valve member 20 and the right end of the cylinder 22 is closed by a labyrinth gland 26 which allows a slow controlled leakage of liquid to take place between it and the outside of the valve member 20. Two small ports 27 are provided through the wall of the valve member 20 leading to the space at the left hand end of the cylinder 22 so that a controlled leakage of liquid into and out of this space can also take place.

The valve member 20 is shown in FIG. 1 in an open positiion in which an internally notched seating ring 28 is spaced downstream away from a resilient sealing washer 29 carried by the fixed closure member 18. With the closure member in this open position, when the spigot 2 is connected to a hose through which a foam making fluid consisting of water and foam compound is supplied, the fluid passes through a coarse mesh screen 30 supported by the spider 19 and thence through the tubular valve member 20, which forms an injection nozzle, and the fluid issues from the downstream end ofthe tubular valve member 20 into the tube 6. In passing into the tube 6, the fluid draws in air through the slots 5 and deflector ring within the tube causes turbulence which converts the fluid and air into foam which issues from the outlet end of the branch pipe- As the fluid flows through the valve member 20 under pressure, some of it flows through the ports 27 and fills the space in the cylinder 22 to the left of the piston 21.

In order to shut off the flow of fluid, some of the fluid is supplied to the space in the cylinder 22 to the right of the piston 21 and the pressure of this fluid acting on the piston 21 moves the valve member 20 to the left so that the ring 28 seats on the washer 29. The supply of fluid to the space in the cylinder 22 to the right of the piston 21 takes place through a passage 31, a tube 32, a pilot valve 33, a tube 34 and a passage 35 all shown in FIG. 2 of the drawings.

The pilot valve 33 is housed in a handle 36 which together with a handle 57 which is attached to the outlet end of the tube 6 as best shown in FIG. 3, is held by the fireman to support the foam-making branch pipe as a whole and direct and control the flow of foam from it. The valve 33 is opened and closed by a twist-grip 37 which is rotatably mounted on the handle 36.

The passage 31 extends axially through a web 38 from an open end just within the periphery of the spider 19 and it then extends radially outwards where it is enlarged to receive one end of the tube 32 which extends through the handle 36. The passage 35 extends substantially radially through the web 38 from an open end within the cylinder 22 just to the left of the labyrinth gland 26 and this passage also has an enlarged portion at its outer end in which the tube 34 is a push fit. The tube 34 also passes through the handle 36 to the valve 33. Thus, when the valve 33 is open, fluid under pressure from the upstream face of the wall 24 flows into the cylinder 22 on the downstream side of the piston 21 and since the force of the fluid is greater than that acting on the face of the seating ring 28, the piston 21 is moved to the left to close the valve in the manner already described. The rate of closure is, however, restricted by the rate at which the fluid within the upstream end of the cylinder 22 can escape through the, ports 27 so that the piston 21 and the cylinder 22 together form a dash-pot.

When the pilot valve 33 is closed, so that no fluid can be supplied from upstream of the wall 24 to the downstream end of the cylinder 22, the pressure of the fluid from the hose acting on that part of the upstream end of the valve member 20 which projects radially beyond the closure member 18 pushes the valve member 20 in a downstream direction into the open position shown in FIG. 1 of the drawings. As the valve member 20 moves, the liquid in the cylinder 22 on the downstream side of the piston 21 escapes slowly through the labyrinth gland 26, so that again the piston 21 and the cylinder 22 form a dash-pot which limits the rate of opening of the valve.

The pilot valve 33 comprises a valve body 39 having, at its right hand end as seen in FIG. 2, two bores side by side. One bore is shown at 40 and receives one end of the tube 32 and the other bore is similar, and receives the adjacent end of the tube 34. The body 39 has an internally cylindrical portion 41 which is coaxial with the bore 40 and contains a plunger 42. A seal is formed between the wall of the cylindrical portion 41 and the plunger 42 by a O-ring 43. The plunger 42 has a transverse bore 44 which receives a pin 45. The pin 45 passes through an inclined slot 46 in the wall of the handle 36 and its outer end is fixed in a hole 47 (see FIG. 1) in the twist-grip 37. A pin 48 projects inwards from the cylindrical portion 41 of the valve body 39 into a groove 49 in the peripheral surface of the plunger 42. The groove 49 is inclined so that it is parallel to the slot 46 through the wall of the handle 36.

A torsion spring 50 wound with opposite hands is mounted in the handle 36 with its mid joint fixed to a cross-pin 52 which extends diametrically through the handle 36. The ends of the spring 50 are located in holes drilled in the twist-grip 37 and extend outwards through a slot 53 (see FIG. 1) in the handle 36. The spring 50 biases the twist-grip 37 in a counter clockwise direction as seen in FIG. 1 and this causes the

pins

45 and 48 both to act on the plunger 42 in such a direction that they push the plunger towards the left as seen in FIG. 2 and this urges a seal washer 54, which forms a closure member, away from a valve seat 55 surrounding the left hand end of the bore 40 in the body 39. Thus the pilot valve is open and fluid is supplied from the tube 32 into the tube 34 and is thus allowed to flow into the downstream end of the cylinder 22 which moves the valve member to the left and stops the main fluid flow.

When the twist-grip 37 is turned through an angle of about 40 in a clockwise direction as seen in FIG. 1, the pin 45 rides along the slot 46 and the plunger 42 is turned so that its inclined groove 49 rides along the pin 48. Thus both the pin 45 and the pin 48 act in concert to move the plunger 42 towards the right as seen in FIG. 2 thus moving the washer 54 on to the seating 55 and closing the pilot valve. This prevents fluid from flowing from the bore 40 into the bore holding the adjacent end of the tube 34 and in consequence fluid cannot flow from the upstream face of the wall 24 into the downstream end of the cylinder 22 and the valve member 20 opens.

In this example the areas of the ports 27 together with the flow area through the pilot valve 33 and the various tubes and passages connected to it are so adjusted that when the twist-grip 37 is turned to open the pilot valve, the valve member 20 moves from its open position to its closed position in not less than 1 second and not more than 2.5 seconds throughout a pressure range of the foam mixture supply of from 50 to 200 psi. The labyrinth gland 26 is arranged to produce a leakage such that the valve member 20 moves from its closed position to its open position in under 1.5 seconds from the instant of operation of the twist-grip 37.

The handle 57 at the outlet end of the tube 6 is fixed to a ducks foot foam deflector 58 which is in turn pivotally attached by a bolt 59 to a stirrup 60. The stirrup 60 which is U-shaped is pivotally connected by a screw 61 and a similar screw on the diametrically opposite side of the tube 6 to a collar 62 which is fixed around the end of the tube 6. The handle 57 and with it the deflector 58 can thus be swung to and fro in the direction of an arrow 63 shown in FIG. 3 and also be rotated in the direction of an arrow 64 shown in FIG. 4 and in a reverse direction.

When the handle 57 is rotated in the direction of the arrow 64 or a reverse direction, the deflector 58 is moved between an inoperative rearwardly projecting position shown in FIG. 4 and a forwardly projecting operative position shown in FIG. 3. When in the latter position it can be swung downwards or upwards to cause it to project further or less far into the stream of foam issuing from the outlet of the tube 6. A sprung catch housed in a boss 65 locates the deflector 58 either in the forward operative position or in the rearward inoperative position.

When the deflector 58 is in the inoperative position, the foam issues from the tube 6 as a stream of circular cross-section. When the deflector 58 is in its operative position and is swung downwards so that it impinges on the stream of foam, it deflects the stream into a fanshape. The foam is also deflected downwards and the reaction of the foam on the deflector 58 tends to tilt the branch pipe upwards and, if the fireman holds it at about face level, the falling foam provides a very effective heat shield but still gives a clear view of the fire over the top of the foam screen.

We claim:

1. In a fire-fighting branch pipe nozzle for discharging fire extinguishing liquid, an improved shut-off valve including a valve member, means moveably mounting said member for movement between closed and open positions, liquid pressure-operated means for moving said valve member between said closed and open positions, means defining a passage leading to said liquid pressure-operated means from upstream of said valve member, a manually operable pilot valve in said passage for controlling the supply of fire extinguishing liquid under pressure to said liquid-pressure operated means, and dash-pot means operative to limit the rate of movement of said valve member from said open position to said closed position under the action of said liquid pressure-operated means.

2. A branch pipe nozzle as claimed in claim 1, wherein said dash-pot means is double-acting and is also operative to limit the rate of movement of said valve member from said closed position to said open position.

3. A branch pipe nozzle as claimed in claim 2, wherein said dash-pot means includes a cylinder, a piston in said cylinder defining spaces in said cylinder on one side of said piston and on the other side of said piston, and means fixing said piston to said valve member, said space on said one side of said piston communicating with said passage whereby when said pilot valve is opened, said space on said one side of said piston is supplied with fire extinguishing liquid under pressure which moves said piston in said cylinder and also moves said valve member.

4. A branch pipe nozzle as claimed in claim 3, wherein said one side of said piston is the downstream side thereof, whereby when said pilot valve is opened, said piston and said valve member are moved by said fire extinguishing liquid under pressure in an upstream direction and towards said closed position.

5. A branch pipe nozzle as claimed in claim 3, further comprising means defining a restricted vent for venting said space within said cylinder on said one side of said piston to provide said double action of said dash pot to control said movement of said valve member from said closed position to said open position.

6. A branch pipe nozzle as claimed in claim 5, wherein said space on said other side of said piston is on the upstream side thereof, further comprising means defining a main flow passsage for said fire extinguishing liquid through said shut-off valve and means defining a restrictive passage communicating said space on said other side of said piston with said main flow passage.

7. A branch pipe nozzle as claimed in claim 4, wherein said valve member is tubular and forms a discharge jet tube for a main flow of said fire extinguishing liquid through said nozzle.

8. A branch pipe nozzle as claimed in claim 7, further comprising an annular flange projecting radially outwards from said tubular valve member, said annular flange forming said piston and projecting radially into ther comprising a handle for holding said branch pipe nozzle, and said pilot valve including a closure member, twist-grip means mounted on said handle and means operatively connecting said twist-grip means to said closure member for moving said closure member between an open position and a closed position upon manual rotation of said twist-grip means on said handle.

11. A branch pipe nozzle as claimed in claim 10, further comprising spring-means spring loading said closure member of said pilot valve to said open position.

Claims

8. A branch pipe nozzle as claimed in claim 7, further comprising an annular flange projecting radially outwards from said tubular valve member, said annular flange forming said piston and projecting radially into said cylinder which is also annular and surrounds said valve member.

9. A branch pipe nozzle as claimed in claim 8, further comprising means defining a main flow passage through said shut-off valve, a closure member, and spider means fixedly supporting said closure member in said main flow passage upstream of said valve member whereby when said shut-off valve is opened, fire extinguishing liquid can flow past said closure member and through said valve member whence it is discharged from said nozzle.

10. A branch pipe nozzle as claimed in claim 1, further comprising a handle for holding said branch pipe nozzle, and said pilot valve including a closure member, twist-grip means mounted on said handle and means operatively connecting said twist-grip means to said closure member for moving said closure member between an open position and a closed position upon manual rotation of said twist-grip means on said handle.