US2277294A - Self-contained flame arrester bank or unit - Google Patents

Description

2% 1942. s. H. BROOKS 2,277,294

SELF-CONTAINED FLAME AfiREsTER BANK on UNIT Filed Aug. 11, 1939 il lll llll lllll lllli UWHEW; INVENTCR.

ATTORNEY.

Patented Mar. 24, 1942 UNlTED STATES ?AT ric SELF-CONTAINED FLAME ARRESTER BANK OR UNIT 1 Claim.

My invention relates to improvements in selfcontained flame arrester banks or units, and it more especially includes the features pointed out in the accompanying claim.

The purpose of my invention is to provide a flame arrester for service on tanks and in pipe lines, etc., containing inflammable substances; that provides a maximum efliciency in operation with a minimum weight and complexity of structure; that .entirely eliminates the use of bolts, screws, etc.; that provides a flow capacity through the arrester unit many times greater than the cross sectional area of the pipe to which the arrester is connected; and that further provides differential thermal characteristics between the aluminum casing and the flame arresting elements of the removable unit.

With these and other ends in view I illustrate in the accompanying drawing such an instance of adaptation as will disclose the broad feature of the invention without limiting myself to the specific details shown thereon and described herein.

Fig. 1 is a front elevation.

Fig. 2 is a side elevation.

Fig. 3 is a side elevation in section.

Fig. 4 is a top plan view in section on line 44 of Fig. 3, showing the tapered edges of the sliding door.

In producing my flame arresters I may use whatever alternatives or equivalents of construction that the exigencies of varying conditions may demand without departing from the broad spirit of the invention.

The flame arrester includes a cast aluminum casing. It has two connecting flanges I, that are provided with openings 2 corresponding to the flow area of the pipes to which the flame arrester is attached. Between the flanges I the body of the arrester is increased in diameter so as to form simulated conical ends 3 which join the flanges to a central portion 4 which has a sliding closure 5 along one face. This has its top and bottom edges 6 tapered lengthwise to approximately .005 inch per inch. The casing at I, for one-half of its horizontal circumference, forms a part of a circle. From this point it is projected to one sidewise to form a square shape in which the door 5 slides in correspondingly tapered grooves 8 across the front of the casing. Within the enlarged center 4 of the casing a containing ring 9 is positioned. This is slidable horizontally in runways ID at the top and bottom of the ring. It is providedwith a convenient knob l l or equivalent by means of which the containing ring 9 with its contents of arrester plates 12 can be bodily removed from the casing through the opening covered in a gas tight manner by the sliding door 5.

Inside of the containing ring 9, there is a plurality of perforated plates l2, which are held in spaced apart relation by separating rings 13. The plates in practice are approximately inch thick and are spaced approximately g to 1 inch apart. They are provided with such a number of openings M of approximately .005? inch diameter as to provide a combined area approximately 330% free area compared to the openings in the attaching flanges I or the effective opening of the pipes to which the flanges are attached. Both are variable.

From this it will be seen that there is an entire absence of screws, bolts, wing nuts, etc., all of which means a minimum expense for producing a finished article, of aluminum casing in actual use weighs approximately one-half of the lightest flame arrester on the market, and approximately one-tenth the total weight of the heaviest form of flame arrester.

The ease of servicing my new form of flame arrester and its eiflciency are outstanding features of the invention. In this connection, it is also pointed out that the cost of machining my device is remarkably low compared to other types of arresters.

The beveled door 5 effectively seals ofi the resister units [2 from the outside air. A simple tap of a small mallet on one end releases the door so as to be easily slid lengthwise to permit the withdrawal of the resister bank I2 as a unit by means of the knob or handle provided.

The ordinary form of flame arrester whether made of aluminum or otherwise presents a most diiiicult servicing problem, because flame arresters for the protection of tanks are usually installed on the tank tops and in cold weather they present a diiiicult servicing problem, which because of the necessity for the removal of bolts clamps, etc., to make the arrester unit accessible becomes a hazardous exploit.

With my device all of these hazards are avoided. The arrester unit through the single operation of sliding back the door makes each plate immediately accessible so that if one or more plates require cleaning a, new plate may be instantly substituted, and the cleaned plates used again over and over.

If desired the end of the door having the thickest portion of the tapered edges may be, if desired, attached to the casing by suitable length chain or otherwise, on which the door after removal from its guideways may be suspended to avoid the necessity of laying the door aside when an arrester unit is to be inspected.

It is customary in the use of flame arresters to require inspections at stated recurring periods. My device makes such inspection easy because, unless replacement is needed, the arrester unit need not be entirely removed from the casing for inspection. As a withdrawal of it even to 60%, it will still be held in the runways of the casing. This is for inspection purposes only. It is of course obvious that when a plate or plates are to be removed in their entirety, the entire unit is taken out of the casing and again replaced after the exchange has been made of a clean plate for an unclean one.

It is an important feature of my invention that the resister plates be placed apart from each other approximately not less than s inch.

If at any time it should be found desirable to make provision for holding the resister plates and associated separating rings from dropping out of the containing ring as the unit is removed from the casing, a bottom flange (not shown) may be formed on the inner face of the containing ring around its lower edge. If desired I may externally shape the perforated plates so that the openings of one plate in relation to the openings of an adjacent plate may be staggered in one or two directions, to cause the free passage of heat through an opening to be deflected by the absence of an opening directly opposite, in the adjacent plate.

It has been found through critical tests that the rapid heat transferring characteristics of cast aluminum used for the flame arrester casing will dissipate heat rapidly, from any explosion or burning of combustible gases within, but should flame continue to burn at the face of the arrester plates, after the initial explosion, then the arrester plates are made of aluminum the heat so generated will gradually increase, this action being more rapid than the dissipation of heat through the casing and after a period of time will increase the temperature of the aluminum plates to a melting point, so that the plate nearest the flame will disintegrate and the succeeding plates progressively disintegrate over smaller central areas until they break through the last plate and cause the gaseous medium which is to be protected against fire to be ignited.

Exhaustive tests have shown that the heat generated at the face of the arrester plates by a constant flame will reach and hold a temperature of from 1800 to 1900 degrees Fahrenheit as long as th flame continues to burn, which accounts for the final disintegration of the aluminum plates mentioned above.

It has heretofore been believed that to arrest flame, it was necessary to use suflicient body of metal as compared to the passageways to absorb the heat of the explosion wave and most arresters heretofore and now manufactured consist of thin aluminum or copper plates set vertically, or in the direction of the flow of gas. Such construction carry the heat through the bank and do not carry the heat directly to the exterior casing to be dissipated to the outside air and in due time will also disintegrate by melting,

The use of the horizontal plate carries heat directly to the casing where it is quickly dissipated and the air spaces between the plates prevent transfer of heat to plates on'the inflow side. By this method the volume and weight of material in the arrester bank is greatly reduced resulting in greater efficiency throughout.

I have also found that by using stainless steel, Monel metal or other like material with higher melting point than the heat generated by a constant flame, in the plate immediately subjected to the explosion wave or exposed to flame, that no disintegration of the plates will occur and a steady flame can burn for an indefinite period without causing ignition of the gaseous medium to be protected against fire.

I have found that all arrester plates may be made of stainless steel, Monel metal or other materialswith a higher melting point than that generated by flame, which is a distinct advantage in preventing and overcoming corrosion and disintegration of aluminum and copper plates now used in all present types of flame arresters, due to acid vapors, salt air, heat and combinations of such and other conditions too numerous to mention.

What I claim is:

In light Weight flame arresters serviceable without the use of nuts or bolts, an aluminum casing having two annular attaching flanges, an enlargement between the flanges, a separate conical connection from the enlargement to each flange, a tangential face on the enlargement eX- tending over its full width and covering the opening leading to its inside, a plurality of separate perforated flame arrester disks positioned within the walls of the enlargement and separable therefrom, a retaining ring positioned around the circumference of all the disks, a plurality of rings between the disks to hold them spaced apart, said rings having an outside diameter corresponding approximately to the outside diameter of the perforated disks and the inside diameter of the retaining ring, a door slidable on the tangential face to cover the opening through which the disks separating rings and the retaining ring as a unit are passed into the inside, slightly tapered top and bottom flanges formed lengthwise of the door on its face, and grooves on the tangential face above and below the opening said grooves being tapered similarly to the tapered edges of the door whereby an end movement of the door will cause the tapered grooves and tapered edges to finally hold the door against the retaining ring to hold the arrester parts assembled and the inside of the arrester tightly closed without the use of nuts or bolts.

STEPHEN H. BROOKS.

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