Discharge Head Having Constant Force Plug Retaining Member

Abstract

A pressure responsive discharge head in which an expellable plug is disposed in the outlet of a body member having an inlet adapted for connection to a source fo fluid, with the plug being connected relative to the body member in a position preventing the discharge of fluid from the outlet. A connector is provided which applies a constant force to the plug to maintain it in the flow preventing position and which is adapted to release the plug in response to a predetermined fluid pressure existing in the body member.

Description

BACKGROUND OF THE INVENTION

The invention relates to a discharge head, and more particularly to a discharge head in which the discharge of fluid therefrom is controlled in response to the pressure of fluid in the head.

Several applications exist for a discharge head in which the flow therefrom is controllable in response to the fluid pressure existing in the head. For example, in applicant's U.S. Pat. No. 3,653,444, assigned to the same assignee as the present application, a fixed fire extinguishing system is disclosed which incorporates a plurality of direct discharge heads spaced apart greater distances and having larger outlet orifices when compared to conventional sprinkler heads, to enable greater quantities of water, or other extinguishant, to be delivered from each head at lower pressures. Preferably, the heads are in the form of wide angle spray nozzles which develop a downwardly directed spray having large size droplets as compared to the droplets produced by the conventional sprinkler heads. According to one of the main features of the system disclosed in this patent, the number of nozzles activated to discharge the extinguishant is limited in order to prevent nozzles located a relatively long distance from the fire to rob more closely located nozzles of valuable extinguishant and extinguishant pressure, and in order to prevent unnecessary water damage.

With this arrangement, the first nozzle actuated by the fire has a much better possibility of extinguishing the fire, because of its ability to retain a predetermined discharge density and the increased ability of the larger droplets to penetrate the fire plume of a high challenge fire. Of course, if the heat of the fire spreads, a limited number of additional nozzles are actuated to help the first nozzle fight the fire and to wet down areas surrounding the fire to provide exposure protection to inhibit the spread of the fire, with the number of additional nozzles that are allowed to be actuated being limited to a small predetermined number in accordance with the foregoing.

According to a preferred embodiment of the above-mentioned system, the above is achieved by establishing a pressure floor so that a minimum pressure must exist at each nozzle before it will open, with the system being designed so that this minimum pressure will not be reached until a predetermined number of nozzles have been opened. The hardware used to establish the pressure floor includes an expellable plug normally blocking the outlet of the nozzle and adapted to be expelled from the nozzle to permit extinguishant flow therethrough upon both the fusing of a conventional temperature responsive device and the presence of a fluid pressure in the nozzles of a magnitude exceeding a predetermined value. In establishing the latter value, a helical compression spring is utilized to latch the expellable plug in a closed position. The design is such that the extinguishant pressure in the nozzle acts upon the helical spring and has to be of a value to overcome the force of the spring before the expellable plug can be released.

In U.S. patent application Serial Number 346,454, filed Mar. 30, 1973, and also assigned to the same assignee as the present invention, a discharge head is disclosed which incorporates the pressure floor feature discussed above in a different manner. In accordance with the latter disclosure, the expellable plug is maintained in a flow blocking position relative to the discharge head by means of a pair of fulcrummed levers. A fusible link maintains the levers in the plug retaining position and is responsive to a predetermined temperature for releasing the levers. A fusible link maintains the levers in the plug retaining position and is responsive to a predetermined temperature for releasing the levers. A spring clip is also provided which maintains the levers in the plug retaining position by virtue of its inherent spring force which, if overcome by the fluid pressure in the body member, releases the lever. The spring clip is soldered relative to the levers by means of a fusible material to provide a failsafe or redundant thermal override which, upon the occurrence of the elevated temperature required to fuse the latter material, permits the plug to release from the head despite the fact that the pressure existing in the latter is insufficient to release the plug.

Although this design proved to be very worthwhile in many respects, it was difficult to ascertain the precise pressure at which the spring clip would permit release of the levers and therefore the plug. Also, the clip could not readily accommodate dimensional variations in the various components of the unit, as well as variations in their relative positions, which further added to its unpredictability.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a discharge head of the above type which incorporates all of the advantages of the heads discussed above, yet which enables the plug retaining force to be accurately and precisely obtained.

It is a further object of the present invention to provide a discharge head of the above type in which the plug retaining force is achieved in a relatively simple manner.

Towards the fulfillment of these and other objects, the discharge head of the present invention comprises a body member having an inlet for a source of fluid under pressure, and an outlet for discharging said fluid, a plug member adapted to attain a position in said housing in which it prevents the flow of fluid from said outlet, said plug member being urged from said flow preventing position by the force of the fluid pressure in said body member, a first linkage member engaging said plug member, a second linkage member engaging said first linkage member, and connector means connecting two of said members in a manner to exert a predetermined force against said plug member in a direction opposite to that of said fluid pressure to maintain said plug member in said flow preventing position when said fluid pressure is below a predetermined value, said connector means being adapted to release said connection when said fluid pressure exceeds said predetermined value and permit the movement of said plug member from said flow preventing position and the discharge of fluid from said outlet, said connector means being adapted to exert said predetermined force despite variations in the distance between its points of connection with said members.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of the discharge head of the present invention as shown in a fully assembled condition;

FIG. 2 is a cross-sectional view taken along the line 2--2 of FIG. 1;

FIG. 3 is a cross-sectional view taken along the line 3--3 of FIG. 1; and

FIG. 4 is a view similar to FIG. 1, but depicting an alternate embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring specifically to FIGS. 1-3 of the drawings, the discharge head of the present invention consists of a hollow cylindrical body member 10 having an inlet 12 formed at one end thereof and an outlet 14 formed in the other end thereof.

The outer surface of the body member 10 is threaded as shown in 16 near the inlet end to permit the head to be connected to a conduit for supplying fluid, such as water, to the head. By way of example, the conduit could form a portion of a fire extinguishing system, in which case the fluid would be in the form of a fire extinguishant, such as water.

A swirl vane 18 is disposed inside the body member 10 near the inlet end 12 thereof for imparting a swirling action to the water as it passes through the head in a conventional manner. A portion of the inner surface of the body member 10 is of a reduced diameter to define a throat 20 which extends into a flared portion forming the outlet 14.

As a result of the foregoing arrangement, water introduced into the inlet 12 is swirled as it passes through the body member 10 with its flow being accelerated as it passes through the throat portion 20 for discharge in a substantially conical discharge pattern from the outlet 14.

As better shown in FIG. 2, a ring assembly 21 is fastened to the outer surface of the body member 10 near the outlet opening 14 and defines a plurality of arcuate slots 21a which communicate with the interior of the body member 10. As a result, a portion of the water passing through the body member 10 will be discharged from the slots 21a in a substantially radial direction to supplement the main discharge from the outlet 14. In this manner, the radially extending discharge provides a "fill in" pattern between the main discharge from adjacent body members 10.

The outlet 14 is normally closed by means of a cylindrical plug member 22 which is retained in the position shown by a pair of levers 24 and 26. In its plug retaining position, the lever 24 has a horizontal leg portion 24a engaging the plug 22, and a shoulder portion 24b extending in a groove formed in the outer wall of the body member 10, to support the lever relative to the body member.

In a similar manner, the lever 26 has a horizontal extending leg portion 26a, and a horizontal shoulder portion 26b also extending in a groove formed in the body member 10. The horizontal leg portion 26a of the lever 26 is fulcrummed relative to the leg portion 24a of the lever 24 about a ball 28 resting on ad adjustable pin 30 supported by the leg portion 26a.

A pair of tabs 32 and 34 extend from the levers 24 and 26, respectively, in a spaced relationship. A fusible link 36, formed of a material that is adapted to fuse, or melt, at a predetermined elevated temperature, connects the tabs 32 and 34, and therefore maintains the levers 24 and 26 in their operative position shown, retaining the plug 22 in the outlet 14.

As better shown in FIG. 2, a coiled spring 20 connects the lever 26 relative to the body member 10. The spring 40 is in the form of a flexible strip of thin material, such as stainless steel, which has one end portion coiled around a shoulder 42 formed on the body member 10, and the other end portion attached to a pin 44 extending from the tab 34 of the lever 26. This latter attachment is preferably made by forming a hole through the spring 40 near its end, and sizing the pin 44 so that it extends within the hole to maintain the spring in the position shown in FIGS. 1 and 2.

As a result of the above arrangement, the spring 40 applies a constant force to the lever 26 urging it into engagement with the lever 24, which, in turn, engages the plug 22 with a predetermined constant force. This constant force is maintained even though, due to tolerance variations, etc., in the various components, as well as variations in their relative positions, the distance between the shoulder 42 and the pin 44 may vary considerably. As a result, the spring 40 can be calibrated so that it applies a force of a precise predetermined value to the plug 22 via the levers 24 and 26 to maintain the plug in the outlet 14 in the absence of a greater force exerted on the other end of the plug 22 by the fluid pressure in the body member 10.

The pin 44 may be of a fusible material, such as solder or the like, which is adapted to fuse at a predetermined elevated temperature of a greater value than that required to fuse the link 36, to enable the plug 22 to be discharged from the outlet despite the fact that the water pressure in the body member 10 does not exceed the force provided by the spring 40, as will be described in detail later.

In operation, the discharge head of the present invention is assembled in its operative condition shown in FIGS. 1-3 with the levers 24 and 26 retaining the plug 22 in the outlet 14, and being maintained in this position by means of the link 36 and the spring 40.

Upon the occurrence of a predetermined elevated temperature in the vicinity of the link 36, the latter will melt, and release the connection between the tabs 32 and 34 and therefore between the levers 24 and 26. After this occurs, if the water pressure in the body member 10 acting on the plug 22 is sufficient to force the plug outwardly from the outlet 14 against the force provided by the spring 40 through the levers 24 and 26, the end portion of the spring 40 will unwind from the shoulder 42 and permit the levers to fall, and the plug to discharge from the outlet.

In the event the fluid pressure in the body member 10 is insufficient to overcome the force of the spring 40 after the link 36 melts, the levers 24 and 26 will remain in their operative position shown unless the temperature proximate to the body member 10 attains the predetermined value which will cause the pin 44 to melt. Upon the occurrence of this latter condition, the spring 40 will be released from the lever 26, and the levers 24 and 26 will fall down under the force of the water pressure acting on the plug, thus permitting the plug, and therefore the water, to discharge from the outlet 14 and the slots 21a.

It is thus seen that the arrangement of the present invention is relatively simple in design, has a minimum of parts and yet provides an effective, precise control of the operation of the head.

The embodiment of FIG. 4 is similar to that of FIGS. 1-3, and identical structure will be given the same reference numerals. In the embodiment of FIG. 4, the coiled end portion of the spring 40 extends around a tab or pin 50 formed on the internal wall of the body member 10. The other end portion of the spring 40 is affixed to the plug 22 at its inner face as shown.

The pin 50 may be of a fusible material which will melt upon a predetermined temperature occurring in the vicinity of the head of a value greater than that required to melt the link 36, to provide a failsafe release in a manner similar to that provided by the pin 44 in the embodiment of FIGS. 1-3.

The operation of the embodiment of FIG. 4 is identical to that of FIGS. 1-3, with the exception that the levers 24 and 26 will fall upon the fusing of the link 36 regardless of the value of the water pressure existing in the body member 10. This will then enable the plug 22 to be discharged from the outlet 14 if the water pressure in the body member 10 is sufficient to overcome the force provided by the spring 40.

Of course, if the water pressure in the body member 10 is insufficient to permit release of the plug 22 the latter will remain in its flow-discharge-preventing-position in the outlet 14 unless the temperature in the vicinity of the head rises to an extent that the pin 50 melts which, of course, will permit release of the plug, as described above.

It is understood that the above embodiments have been described in connection with a fire protection system by means of example, and that the discharge head of the present invention can be used in other environments as well.

Of course, other variations of the specific construction and arrangement of the discharge head disclosed above can be made by those skilled in the art without departing from the invention as defined in the appended claims.

Claims

I claim:

1. A discharge head comprising a body member having an inlet for a source of fluid under pressure, and an outlet for discharging said fluid, a plug member adapted to attain a position in said body member in which it prevents the flow of fluid from said outlet, said plug member being urged from said flow preventing position by the force of the fluid pressure in said body member, and connector means connecting said plug member relative to said body member in a manner to exert a predetermined force against said plug member in a direction opposite to that of said fluid pressure to maintain said plug member in said flow preventing position when said fluid pressure is below a predetermined value, said connector means being adapted to release said connection when said fluid pressure attains said predetermined value and permit the movement of said plug member from said flow preventing position and the discharge of fluid from said outlet, said connector means being adapted to maintain the value of said predetermined force despite dimensional variations in said members and variations in the relative positions of said members.

2. The head of claim 1 wherein said connector means comprises a strip of flexible material having a coiled portion, said strip of flexible material being fixed relative to said body member and to said plug member.

3. The head of claim 2 further comprising linkage means for engaging said plug member to retain it in said flow preventing position, said linkage means including a fusible link responsive to a predetermined temperature in the vicinity of said body member for releasing said engagement, said plug member moving from said flow preventing position upon the existence of both said predetermined temperature and said predetermined value of fluid pressure.

4. The head of claim 3 wherein a pin is formed on the interior wall of said body member, said strip of flexible material having one end portion coiled around said pin and the other end portion attached to said plug member inside said body member.

5. The head of claim 4 wherein said pin is adapted to fuse at a temperature higher than the fusion temperature of said fusible link to permit release of said plug member despite said fluid pressure being below said predetermined value.

6. The head of claim 1 further comprising linkage means for engaging said plug member to retain it in said flow preventing position, said connector means comprising a strip of flexible material having a coiled portion, said strip of flexible material being fixed relative to said body member and to said linkage means.

7. The head of claim 6 wherein said linkage means includes a first lever engaging said plug member and a second lever engaging said first lever, said strip of flexible material being fixed relative to said body member and to said second lever.

8. The head of claim 7 wherein said linkage means further comprises a fusible link connecting said levers in a manner to maintain said plug in said flow preventing position, said fusible link being responsive to a predetermined temperature in the vicinity of said body member for releasing said connection, said plug member moving from said flow preventing position upon the existence of both said predetermined temperature and said predetermined value of fluid pressure.

9. The head of claim 8 further comprising a fusible pin connecting said strip of flexible material to said second lever, said pin adapted to fuse at a temperature higher than the fusion temperature of said fusible link to permit release of said plug member despite said fluid pressure being below said predetermined value.

10. A method for controlling the operation of a discharge head in which a plug member is disposed in the outlet of said head to normally prevent the flow of fluid therethrough, comprising the steps of exerting a predetermined force against said plug member in a direction opposite to that of said fluid pressure to maintain said plug member in said flow preventing position when said fluid pressure is below a predetermined value, releasing said force when said fluid pressure attains said predetermined value to permit the movement of said plug member from said flow preventing position and the discharge of fluid from said outlet, and maintaining the value of said force despite dimensional variations in said members and variations in the relative positions of said members.

11. The method of claim 10 further comprising the step of exerting an additional force against said plug member in a direction opposite to that of said fluid pressure, and releasing said additional force in response to the temperature in the vicinity of said head exceeding a predetermined value.

12. The method of claim 10 further comprising the step of releasing said force in response to the temperature in the vicinity of said head exceeding a predetermined value despite the absence of said predetermined value of fluid pressure.