US3144276A - Apparatus for uniformly mixing and distributing dry powder fire extinguishing chemicals - Google Patents

Description

1, 1964 J. ORTIZ APPARATUS FOR UNIFORMLY MIXING AND DISTRIBUTING DRY POWDER FIRE EXTINGUISHING CHEMICALS Filed April 23, 1962 United States Patent 3,144,276 APPARATUS FOR UNIFORMLY MIXING AND DISTRIBUTING DRY POWDER FIRE EX- THNGUISHING CHEMICALS .lohn Ortiz, Elrnsford, N.Y., assiguor to Safety First Products Corporation, Elmsford, N.Y. Filed Apr. 23, 1962, Ser. No. 189,381 1 Claim. (Cl. 30264) This invention relates to a method and apparatus for mixing and distributing dry powder fire extinguishing chemicals propelled in a closed piping system by an inert gas and more particularly to a method of conveying a uniform suspension of dry powder fire extinguising chemicals over an oil fire in order to rapidly and efficiently extinguish the fire.

A method of conveying fire extinguishing dry powder chemicals is shown in US. 2,708,605. This method recognizes the fact that after centrifugal separation of rapidly moving susponsoid particles at a ninety degree elbow, that a minimum linear travel is necessary before uniform mixing naturally takes place. Thus the patented method is restricted to at least the distance beyond an elbow before natural mixing takes place. Accordingly after each elbow of the proces of US. 2,708,605 a minimum travel distance is necessary before a T-joint in the piping may be used.

This invention is a vast improvement over Guise et al., US. 2,708,605 since it is not restricted or limited to any linear travel whatsoever before effecting a uniform sus pension of particles and gas.

It is an object of this invention to provide a moving suspension of uniform density substantially immediately after passage beyond a right angle elbow.

It is another object to provide a means of mixing separated layers of gas and solid particles.

It is a further object to provide a method and apparatus for rapidly mixing Stratified moving gases and solid particles without need for linear travel.

These and other objects of this invention will become apparent upon reading the following descriptive disclosure taken in conjunction with the accompanying drawing in which;

FIG. 1 is a schematic plan view, partly in section and showing the manner of mixing and conveying dry powder beyond a right angle bend and to a bi-furcated piping system for distribution to nozzles disposed in opposed relationship over an oil bath, such as is used for quenching glowing metal to harden it,

FIG. 2 is a horizontal section view of a venturi means used in this invention for mixing separated gases and solids, and

FIG. 3 is a plan view partly in section of a modified distribution system using a plurality of opposing nozzles.

This invention is used principally in the extinguishing of oil fires and particularly oil fires that may result when for example glowing steel is hardened by quenching in an oil bath.

Turning to the drawing, an inlet conduit 10, connected for example to a suitably large pressure resistant tank under suitable pressure of, for example, nitrogen gas is connected to a threaded right angle pipe elbow 11. The tank contains a syphon tube and the dry powder fire eX- tinguishing chemical, for example, sodium bicarbonate is propelled through conduit and elbow 11. Because of the speed of travel of the suspension, the solid particles of chemicals are thrown outwardly in their travel in elbow 11 so that there is a substantial separation of the gas and the solid particles after passage through said elbow 11.

According to this invention, means are provided that may be connected directly or indirectly to the elbow 11, to effect a uniform mixing of the separated gas and solid 3,144,276 Patented Aug. 11, 1964 phases. The means employed is a venturi conduit (FIG. 2) inserted into the piping immediately after the ninety degree travel in the elbow 11 and the process of this means is one of venturizing or mixing of solid particles and gas by venturi action.

As shown in FIG. 1, a fully threaded conventional nipple 12 is employed and a conventional expansion joint 13, of larger internal diameter than the nipple 12, is secured thereto. A suitable section of large diameter pipe 14 is threaded into joint 13 near elbow 11 and a second and like expansion joint 13X is secured to the far end of said pipe 14 in a reversed relationship to joint 13 to engage a pipe 15 of lesser diameter than pipe 14.

Clearly, where joint 13 is provided with exterior threads adjacent to elbow or L-fitting 11, it may be used in lieu of nipple 12. In short, where joint 13 is suitably threaded exteriorly and away from pipe 14, it may be connected directly to elbow 11, thereby dispensing with the use of nipple 12.

As shown in FIG. 2, the venturi conduit 16 is provided with a smooth walled cylindrical exterior of a suitable diameter such as to enable a tight press fit into the diameter of the coacting pipe 14.

The venturi conduit 16 is provided with a suitable inlet cone aperture 17 having, for example, an angle of ninety degrees to the horizontal plane. The conduit is also provided with an exit cone orifice 18 having for example an angle of ten degrees to the horizontal plane. In other words, the cone angle of the extrapolated cone would be twenty degrees for the exit orifice. Preferably, a horizontal tubular and cylindrical passageway 19 is provided of a suitable length. However, venturi conduits having no tubular length 19 are operable.

In the operation of this invention, the two separated phases of rapidly moving gas and solid particles are squeezed together in the inlet cone 17 and upon expansion in the outlet cone 18 a uniform mixing of gas and solid particles is produced, due to the gas expansion in cone 18.

Thus the suspension of solid and gas beyond the venturi conduit 16 is of uniform density per unit volume, for example, per cubic inch. Accordingly, the fire extinguishing suspension is of uniform density in conduit 15 and T-joint or T-fitting 20. In T-joint 20 the uniformly mixed gas is uniformly divided so that half of the stream goes to conduit 21 and the other half to conduit 22.

The moving suspension stream, both in conduits 21 and 22 thus move a like volume of suspension per unit of time to each side of the oil bath tank 23. Elbows 23 and 24 are secured respectively to conduits 21 and 22 and respectively to conduits 25 and 26.

An elbow 27 is secured to conduit 25 and a suitably horizontally flared conventional expansion nozzle 28 is secured directly thereto, or optionally first through an intermediate short length of conduit, if desired. Similarly, an elbow 29 is secured to conduit 26 and a conventional expansion nozzle 30 secured thereto.

Thus for small oil bath 23, a pair of opposed expansion nozzles 28 and 30 will dispense opposed clouds of powder over the surface of the flaming oil in oil bath 23 to rapidly extinguish the fire. In conventional practice, a fire detection unit is located over the oil bath 23 so that in the event of fire the system is automatically actuated, causing the suspension to flow through the piping (FIG. 1) and thus extinguish the fire automatically.

Where a large rectangular oil bath 31 is employed, it is necessary to employ more than a single pair of opposed nozzles as shown in FIG. 1. In such cases, the elbows 27 and 29 are secured to a length of pipe or conduit 32 and 33 respectively and a suitable venturi conduit 16X is press fitted into each of the conduits 32 and 33. It is to be noted that conduits 25 and 32 as well as conduits 26 and 33 are of like diameter. However, conduit 14 is of greater internal diameter than is the internal diameter of nipple 12.

However, a piping system having an expanded conduit 14 adjacent to the exit of the elbow 11 closest to the tank dispensing suspension into a conduit 10 is preferred, because of the added expansive eifect given by the greater diameter of conduit 14. However, a throughout uniform diameter piping system is operable.

As shown in FIG. 3, conduit 32 containing remixed suspension of uniform density is distributed through a T-joint 34 to lateral conduits 35 and 36 and through elbows 37 and 38 respectively to nozzles 39 and 40. Similarly, conduit 33 leads to T-joint 41 and thence to lateral conduits 42 and 43 and connecting elbows 44 and 45 and the nozzles 46 and 47 connected respectively thereto.

Thus for small oil baths 23, a single venturi conduit 16 suffices to obtain equal distribution of solid particles to each side of the tank (FIG. 1). But for larger tanks, other venturi conduits 16X may be used on each side of the tank 31 to obtain equal powder distribution at the .nozzles.

This invention has been illustrated by means of a plurality of embodiments but it is not to be limited to these illustrations since various inlet angles and outlet angles are operable.

I claim:

A compact piping system for uniformly distributing dry powder fire extinguishing chemicals by means of a gas over the surface of an oil bath comprising opposed inwardly directed nozzles on opposite sides of said oil bath, said nozzles being jointly connected with a source of dry powder fire extinguisher chemicals by pipe means comprising a length of pipe having a downstream T-fitting and an upstream L-fitting, said length of pipe having a press fitted venturi insert adjacent said L-fitting whereby rapid mixing of solids particles and gas is effected immediately beyond the L-fitting to provide equal discharge from the two arms of the T-fitting to said nozzles disposed on each side of the oil bath.

References Cited in the file of this patent UNITED STATES PATENTS 1,443,944 Brush Feb. 6, 1923 1,475,556 Horning Nov. 27, 1923 1,526,963 Chandler Feb. 17, 1925 1,530,157 Edwards Mar. 17, 1925 1,727,045 Asire Sept. 3, 1929 1,970,405 Thomas Aug. 14, 1934 2,695,265 Degnen Nov. 23, 1954 2,708,605 Guise May 17, 1955

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