US2693294A - Flame arrester - Google Patents

Description

Nov. 2, 1954 Filed June 21, 1951 H. A. QUIST FLAME ARRESTER 2 Sh et's-Sheet 1 R. HAROLD A. QUIST ATTORNEYS QulsT FLAME ARRESTER Nov. 2, 1954 2- 5heots-Sheef. 2

Filed June 21, 1951 INVENTOR. HAROLD A. QUIST ATTORNEYS United States PatentOi' 2,693,294 FLAME ARRESTER Harold A. Quiet, Elkton, Ma, assig'nor to Sun Oil com:

pany, Philadelphia, Pa., a corporation of New Jersey Application June 21, 1951, Serial No. 232,841

'7 Claims. (Cl. 220-88) the use of a'flame arrester a greater hazard than if it,

were abandoned entirely. There is yet another point of view whichconsiders flame arresters satisfactory for use only where vacuum conditions are experienced and the movement of the relieving gas is inwardly through the arrester to the body ofvolatile liquid. Again, some uses restrict the season during which the arrester covers the venting apparatus to the spring, summer, and fall seasons, removing the devices during the winter months to avoid the icing condition. Under these limitations of mechanical defects and special uses, industry has in general considered abandoning the flame arrester of the type under discussion or in greatly restricting its use to particular seasons and conditions; It is an object of this invention to provide a flame arrester for general and unlimited use which is maintained free of clogging matter, yet is operative under conditions of both pressure and vacuum to break the travel of flame along streams of combustible gas moving to and from storage receptacles to give positive and reliable fire protection. The present inventionincludes a housing in which a non-freezing, non-volatile liquid with cleansing properties is maintained at a predetermined depth. A recipro-' cating flame arresting member of. the tubular type is pivotally positioned to be cleansed and maintained in safe operable'condition by this liquid. In the housing, above vthe liquid. level, gas transmitting conduits are placed to direct the flow of combustible and relieving gases in a path to and from the storage tank through the housing body. The flame arresting member is so positioned as to reciprocate in response to conditions of either pressure or vacuum in the storage tank to which it is attached, thereby causing a washing action in the liquid and movement to a position across the flowing gas stream during the relief period.

In order that a better understanding of the invention may be had, references are made, to the following detailecll1 description and to the accompanying drawing in whic Figure l is a plan view of the device with the cover partly broken away. I v

Figure 2 is an elevation in section along line '22 of Figure 1. V

Figure 3 is a sectional elevation along line 3-3 of Figure 1.

Figure 4 is a sectional elevation of a part of Figure '3 along the line 44.

Figure 5 is a sectional elevation showing operation under vacuum conditions.

Figure 6 is a sectional elevation showing operation under pressure conditions;

, The preferred embodiment of a flame arrester of the type described. which overcomes the enumerated objections and will operate equally well for both pressure and vacuum relief conditions, is shownin Figures 1 to 4 2,6932% Patented Nov. 2, 1954 inclusive to which reference is now made. The housing 10 is designed to hold a body of liquid 12 maintained at an operating level as shown. Reservoir devices for maintaining liquid levels in housings for sealing purposes are well known. As such a device forms no part of the present mechanism and is not claimed, a description of such a sub-element is omitted. A flame arrester member 14 of the tubular type is pivoted as at 1616 so as to be totally submerged beneath the level of liquid 12 when in the inoperative position and also to rotate into operating position as later discussed and shown in Figures 5 and 6. The flame arrester member 14 is of the multiple capillary passage type readily constructed by assembling corrugated aluminum plates cut to proper length and width and joined together so as to form a tubular structure through which the relieving gases must pass. This structure is well known in the art and is illustrated and discussed, for example, in the patent to Steward, Number 958,944, issued May 24, 1910. The periphery of the flame arrester member 14 is formed to fit closely to the interior of the housing so as to prevent the flame of a burning combustible gas from traveling unobstructedly along the stream of this inflammable gas back into the storage tank 18 during the relieving operation.

In the preferred embodiment, the flame arrester housmg 1!) is connected to a venting mechanism, such as a pressure control valve shown diagrammatically as at 20 which is, in turn, connected to the storage tank 18 by a conduit 22. Another conduit 24 connects the venting mechanism 20 to an opening 26 in the housing 10 of the flame arrester above the level of the liquid 12. Another opening 28 in the housing is adapted to receive the conduit 30 which is open to the atmosphere or connected to another conduit as desired. The openings 26 and 28 are both arranged above the level of the liquid 12 so as to direct the stream of relieving gas in either direction across the housing above the body of the liquid.

The top 32 or the housing wnich forms the upper closure for the path of the relieving gases above the liquid level is shown as arched in the sectional elevation of Figure 2 and as rectangular in shape in the plan view of Figure 1. This is the form of the preferred embodiment and represents the simplest type and probably the least expensive to manufacture. A circular device in plan with a domed top will be readily recognized as an acceptable form and suggests other variations in shape. However, the form adapted for use requires only that the reciprocable flame arrester member be of such shape and so positioned as to move from washing engagement in the cleaning liquid to completely intercept the stream of relieving gas under conditions of either vacuum or pressure as that gas passes through the flame arrester housing. A further precaution to properly position the flame arrester member is taken by locating strips or ribs 34 and 36 inside the top 32 of the housing 10 to hold the flame arrester member 14 in the proper position to intercept the flow of the relieving gases and eliminate a peripheral area which might possibly transmit flame.

To present a complete operating unit which can be adapted to any storage tank or other venting mechanism with the least alteration to existing equipment, the preferred embodiment is illustrated as including its own actuatingmech'anism. It will be readily understood that where the venting device noted diagrammatically by the numeral 20 in our figures is of a reciprocating type, the flame arrester member may be connected to be actuated by the valve through use of proper linkage. Or, another alternative may be adopted, readily discerned by those versed in the art, and the actuating mechanism about to be described maybe separated completely from the housing of the flame arrester and used to operate one or more arresters. However, the spirit of the invention will be fully understood through the description of the preferred device as illustrated where the actuator and flame arrester are in the same housing on opposite sides of a separating partition.

The actuator of the illustrated preferred embodiment comprises an arcuate cup 38 which is operably mounted in a separate chamber 44 under the cover 32 of the flame arrester housing 10. This is facilitated by a partition 48 projecting downwardly from the top 32 of the hous ing 10 to separate the actuator chamber 44 from the flame arrester chamber here noted as 46. This construction is clear in Figure 3 of the drawing. Thev pivot axis 16 of the flame arrester member 14 is also shown in this figure as having a suspension point in the partition 48. A feature of this partition is its location whereby it is sufficiently submerged in the liquid 12 to prevent the escape of relieving gases from chamber 46 into chamber 44 to obstruct the reciprocation of the actuator cup 38. The actuator 38 is adjusted as shown in Figures 2 and 3 to be in the normal position when the arrester member 14 is substantially parallel to the surface of the liquid 12 and totally submerged therein. Total submergence of the arrester member insures complete protection of the device in the preferred embodiment, but washing contact is considered as suflicient under normal conditions. A bracket 42, or similar fastener, joins the actuator cup 38 to the pivoted supporting axis 16 to which the flame arrester member 14 is fastened. Pressure transmitting conduit 50 connects the interior of the actuator cup 38 above the liquid level with the vapor space of the storage tank 18. The conduit 50 is arced to curve with the actuator 38 about the center of the common axis 16 of the arrester member. That part of the housing 10 which encloses this part of the device and noted as chamber 44, is extended to permit free movement of the flared end of the actuator cup 38, noted here by the numeral 52, which is necessitated in order to enclose the conduit 50 Without binding during operation as will be more clearly understood by reference to the latter part of this specification. As has here been noted above, the partition 48 is constructed to project downwardly into the body of the sealing liquid 12 to separate the housing 10 into twochambers, namely 44 and 46, primarily to prevent the pressure of the relieving gases passing through chamber 46 from affecting the actuator operation. It will be evident that full movement of the actuator 38 in a clockwise direction as viewed in Figure 6, would be opposed by the liquid 12 which fills the chamber 44 as well as the chamber 46 to the same level. Consequently, it is necessary to include a receiving cup 54 which is positioned within the liquid body, as shown in all the figures of the drawing, to receive the upper end of the actuator 38 as it rotates to lift the flame arrester 14 into the pressure venting position. This removes the interference of the liquid body 12 and permits the complete operation of the device. A drain 56 is arranged to remove condensate and liquid which might drip from actuator 38 or otherwise be deposited in the cup 54, admits air at atmospheric pressure to assist in the vacuum operation, and relieves the chamber 44 of air during the pressure relieving movement.

To those versed in the art, a study of the descriptive matter above, together with the figures of the drawing, will be sufficiently clear to indicate the full and correct operation of the disclosed device. However, in order to emphasize the advantages of the preferred embodiment, a complete description of the operation of the device under both vacuum and pressure conditions will be detailed. Reference will be made to all the figures of the drawing for a full understanding of the operation, and particularly to Figures and 6 which show the position of the flame arrester member 14 in vacuum relief and pressure release operations respectively.

Preliminary to using the flame arrester of this disclosure for coo eration with a pressure relief valve, it is necessary to etermine the size of the device to afford the most eflicient operation. This can readily be ascertained, as will be recognized by those versed in the art, by a consideration of the combined requirements of both the venting device 20 and the size of the volume to be vented, shown here as the storage tank 18. In unusual cases, it may be necessary to couple one actuator to several flame arresters each of which is connected to a relief valve 20 or similar venting device. Once the combined assembly of relief devices and flame arresters to be used is determined, and the size of the flame arrester is therefore known, the actuator for the proper operation of the flame arrester is easily designed.

To properly protect against fire and explosion, it is necessary that the activation and complete operation of the flame arrester member anticipate the passage of the" relief gases through the housing 10. It will be recognized by those versed in the art that this operation can be achieved by setting the venting mechanism 20v to follow the operation of a more sensitively arranged flame arrester. Changes in the dimensions of the actuator as shown, particularly with reference to the size of the pressure transmitting conduit 50 and the relative cooperating area of the actuator cup 38, is an immediate solution to increased sensitivity of the flame arrester actuator. As a complement to this increased activity, the relief device 20 can be retarded by any well-known means, such as weights or pressure settings or any of the other well-known methods which are inherently characteristic of the valve or device used.

For a complete understanding of the operation of the flame arresting device here disclosed in cooperation with a venting mechanism, the combination of which is specifically suggested, reference is made to all of the figures of the drawing and particularly to Figures 5 and 6 which show the flame arrester operating under conditions of vacuum and pressure, respectivel .In the Figures 1 to 4 inclusive, the flame arrester is shown in the normal position when it is subjected to neither pressure exhaust norvacuum relief. In this neutral position, the flame arrester member 14 is submerged in the non-freezing, noninflammable cleansing liquid 12, which may be glycol, glycerine, or a light petroleum oil specially treated. As the flame arrester is active periods, the surfaces of the arrester member are not subject to the clogging action of insects or the formation of ice which is a primary objection to devices of this type. Thus, the flame arrester is constantly maintained in a clean and fully operable condition.

Under vacuum relieving conditions, the device assumes the position shown in Figure 5. As was indicated above, the size of the relative parts of the flame arrester for our. operations is selected to respond to the specific tank conditions preliminary to the operation of the venting device. The actuator is proportioned to recipro cate the flame arrester member under the efiect of predetermined conditions in anticipation of the flow of relieving gas through the housing 10 above the surface of the sealing liquid. The certain response of an operable arrester member in anticipation of the flow of the relieving gas by positioning the arrester member so that the gas is required to pass through it under all conditions of flow, is the assurance of safety.

Returning to a further consideration of Figure 5, the vacuum conditions in the storage tank 18 may be induced as by pumping liquid out of the tank, the reduction of surrounding temperatures, or other reasons which are well known to those who store volatile liquids. The negative pressure of the vacuum condition is transmitted to both the venting mechanism 20 and to the disclosed flame arrester actuator equally and at the same time. As already explained, the flame arrester actuator is designed to be more sensitive than the relieving devices and operates in advance of the flow of any relieving gas through the housing 10. As the negative pressure condition increases in the actuator cup 38, it is opposed by atmospheric pressure admitted through the drain 56,

creating the necessary operating pressure differential. The actuator cup 38 moves downwardly over the conduit 50 into the sealing liquid. The flared lower end of the actuator cup 38' permits the arcuate movement of the cup about the conduit 50 without obstruction. The fastener or bracket 42 connects the actuator 38 to the mounting. pivotal axis 16 of the flame arrester member 14 and reciprocates the member 14 to the position shown.

in Figure 5 in contact with the rib 36. This movement from the body of liquid illustrated in the preferred embodiment, or into contact with the liquid body suggested as a proper modification, causes a washing. action to clean the transmitting surfaces of the flame arrester member. In the lifted position, the flame arrester member 14 fits closely within the perimeter of the top 32 of the housing. 10 and intercepts the flow of relieving gas (air in this case) through conduit 30' into the housing 10 and throughthe conduit 24 and the venting mechanism 20 to relieve the vacuum condition in the tank 18. It will be noted by the arrows on Figure 5 which indicate the direction of flow of the relieving gas that there is a pressure drop between the side where the relieving gas enters the flame arrester member 14 at the exit side. This difference in pressure assists in keeping the reciprocating flame arrester member in-the during the relieving period. With the relieving of the totally submerged during these in-,,

proper arresting position pressure vacuum condition, and the balance of pressure within the storage tank 18 is resumed, the actuator returns the flame arrester member to its neutral position into contact with the liquid 12 from which it starts. This reciprocating movement in response to the movement of the actuator causes a washing action in the tubes of the flamearrester member and removes any foreign matter such as insects, condensation, or gummy substances which otherwise obstruct a stationary arrester. 7 From the above disclosure of the relief of a vacuum condition, the pressure exhaust condition as shown in Figure 6 will be readily understood. Among the conditions of storage which build up a pressure may be noted arising temperature, the pumping in of additional fluids to be stored, and other familiar operations well known to the industry. These operations cause an excessive increase in pressure which is transmitted to the flame arrestor actuator 38 through the conduit 50 and at a predetermined value lifts the inverted arcuate cup causing the flame arrester member 14 to assume a position against the rib 34 and in close peripheral proximity to the top 32 of the housing 10. Any opposition to the upward movement of the actuator cup 38 by air in the chamber 44 is relieved through the drain 56 which opens to the atmosphere. Except for the direction of reciprocation, the movement of the flame arrester member 14 is caused by the actuator 38 through its attachment to the pivotal axis 16 by the connecting means 42 similarly to the explanation made for this movement under vacuum conditions above. Having come to rest in contact with the rib 34, the flame arrester member 14 is in position to intercept the movement of the relieving gases which pass from the tank 18, as shown by the arrows on Figure 6, through the venting mechanism 20 and enters the upper part of housing from the conduit 24. A pressure drop is established here as was explained above for the vacuum operation which also assists in firmly holding the flame arrester member in operating position. The venting gas then moves across the surface of the liquid 12, through the tubular structure of the flame arrester member 14 as shown, and escapes from the arrester housing through the conduit 30 go either a collecting main or the atmosphere as desire As was indicated above in discussing the vacuum condition, the reciprocation of the flame arrester member; 14 by the actuator action causes a washing efiect which keeps the arrester member clean and free of any clogging substances. Inasmuch as this. device reciprocates in different directions, depending upon the vacuum and pressure condition to be relieved, this washing action is accentuated by causing the liquid to wash through the tubular construction of the flame arrester member in several directions. As a result, the relief of dangerous pressure conditions of storage is assured by a constantly maintained free flame arrester passage.

From the above description, it will be apparent that an apparatus is provided which overcomes the principle objections to flame arresters of this type. The apparatus is illustrated and described as the preferred embodiment of the invention presenting a safety device which is responsively operative to the pressure conditions within the volume to be relieved and which canont fail due to the obstruction of foreign matter on its surface. It is designed to be anticipatively responsive to the same conditions which actuate storage tank venting devices and is readily connected to any of the known and accepted relief mechanisms. With little change, it may be directly attached to venting valves of the rotating breather type and be caused to operate directly with such a valve. Under conditions Where the actuator of the venting mechanism is enclosed in thestorage tank, it may be readily coupled to such an actuator and made responsive to it. Although preferred to operate with a venting device as herein disclosed, it will be recognized that an arrester as described here can be, with'no inventive alterations, made to respond to the pressure variations within a storage tank and may be operated directly from the storage tank without an intervening pressure venting mechanism. An example of a condition favorable to the use of the flame arrester alone, without a venting mechanism is found where substantially non-volatile, yet inflammable liquids are stored. In short, the cleansing and response features of the rotatable flame arrester '6 member in contact with a protective and cleaning bath are readily-adapted to venting conditions of any kind.

It is obvious, therefore, that the construction and arrangement of the partsmay be varied in many ways without departing from the spirit of the invention. It is to be understood that the invention is no to be limited to the'specific form and arrangement herein, except as such limitations are specified in the following claims.

I claim:

'1. A flame arrester comprising a housing having a passage for the flow of gases therethrough, a cleansing liquid therein maintained proximate the flow passage, a reciprocable flame arrester memberpivotally mounted in said housing in normally submerged contact with the liquid and reciprocable to obstruct the gas flow passage, and actuating means operably connected to reciprocate the arrester member in response to the gas pressures relieved through said housing.

2. A flame arrester comprising a housing, a vertically disposed partition dividing the upper portion thereof into an arresting chamber and an actuator chamber, a cleansing liquid in said housing maintained at an operating level to seal said chambers by engaging the dividing partition, opposed gas flow vents in the arresting chamber above the liquid level, a reciprocable capillary flame arrester member pivotally mounted in the arresting chamber below the level of the cleansing liquid, said member being rotatable to intercept the flow of gas between said vents, and actuating means in the actuator chamber connected to reciprocate the arrester member between the liquid and the flow of gas.

3. The flame arrester defined in claim 2 further characterized by the actuating means in the actuator chamber including an inverted cup operably mounted in sealing engagement with the liquid therein, and a pressure transmitting conduit opening into said cup above the liquid level.

4. A flame arrester mountable on a storage tank comprising an arrester chamber adapted to contain a cleansing liquid at a predetermined level and having above said level an air vent, and alongside said arrester chamber an actuating chamber having an air vent, an inverted cup in the actuating chamber and a flame arrester in the operating chamber, both pivotally mounted and swingable together on the same horizontal axis, and means adapted to afford gaseous communication between the tank and the cup and the tank and the arrester chamber respectively; said flame arrester member being positioned, under conditions of balanced pressure between the tank and the atmosphere, to assume a horizontal position in submerged contact with the liquid and under conditions of unbalanced pressure between the tank and the cup to be swung with the cup on said axis to project an end portlion of the flame arrester member above the liquid eve 5. The construction defined in claim 4 in which the flame arrester is pivotally mounted between its ends below said liquid level and is swingable in opposite directions on its axisupon rise of tank pressure above, and fall of tank pressure below, atmospheric pressure, the air vent in the arrester chamber and the communicating means between such chamber and the tank being located on opposite sides of the arrester chamber to thereby, under said conditions of unbalanced pressure, constrain flow of gaseous fluid through the end portion of the flame arrester member projecting into the space above said liquid level.

6. A flame arrester comprising in combination a housing having a gas flow chamber in the upper portion, a sealing liquid in*the lower portion forming the lower surface of the gas flow chamber, opposed gas flow vents in the gas flow chamber above the liquid level, a re ciprocable capillary flame arrester member pivotally mounted to be submerged within the liquid in a normally horizontal position; an actuator housing having an atmosphere filled space in the upper portion, a sealing liquid in the lower portion, an inverted cup mounted in sealing engagement with the liquid therein, a pressure transmitting conduit opening into said cup above the level of the sealing liquid; and connecting means linking the reciprocable flame arrester member to the inverted cup to swing the same from the immersed position in the cleaning liquid to a position of gas flow interception between the gas flow vents in the arrester housing.

7. A flame arrester comprising a housing having a 7 vertical partition depending from the top thereof and dividing the upper portion into a gas flow chamber and an actuator chamber, a body of liquid in the lower portion of the housing maintained at suflicient depth to engage said partition in sealing contact and operably separate the chambers therein, opposed flow vents in the gas flow chamber above the liquid level, a Teciproca'ble capillary flame arrester member axially supported in said gas flow chamber, pivot supports for the axis of said arrester member positioned below the 'level of said liquid therein, an inverted actuator cup in said actuator chamber operably suspended in sealing contact with the liquid therein, a pressure transmitting conduit extending into said actuator cup and opening therein above the liquid level, and connecting means coupling the arrester 15 2,587,943

member to the actuator cup whereby the arrester swings on its axis from the liquid to a gas flow intercepting position in the gas flow chamber in response to pressures affecting the cup in the actuator chamber.

References Cited in the file of this patent UNITED STATES PATENTS Wiggins Mar. 4, 1952

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