US2482457A - Combination check valve and flash arrester - Google Patents

Description

S pt- 20, 1949. w. s. BOEDECKER 7 2,482,457

, COMBINATION CHECK VALVE AND FLASH ARRESTER Filed March 23, 1945 IN V EN TOR.

Patented Sept. 20, 1949 CHECK VALVE AND ARRESTER' COMBINATION FLASH Woodrow S. Boedecker, Chicago, Ill., assignor to The Bastian-Blessing Company, Chicago, 111.,

a corporation of Illinois Application .March 23, 1945, Serial No. 584,332

, This invention relates to a safety device such as a flash arrester used in conjunction, with equipment dispensing acetylene gas or oxygen.

Inhandling acetylene or oxygen the danger of dissociation or back fire through the system is always present due to the temperament of acetylene and its high flame propagation and to the.

oxidizing ability of oxygen if there is any trace of a fuel or ferrous material in the line.

In order to prevent any flame or pressure wave from reaching the storage tank in which such gases are stored, flame arresters have been designed which either add to the hazard unintentionally by becoming defective in use and creating a false impression of safety or are inadequate for extreme conditions. Other flash arresters materially retard the flow of gas under heavy load conditions or, if designed to handle heavy load conditions, are too bulk to be managed conveniently. a

Not only does the present invention overcome these diificulties but it also checks the pressure wave which very often accelerates the activity of the flame wave. In fact, in some instances if the pressure wave, which precedes the flame wave slightly, can be checked, the flame wave can be brought under control before any definite hazard is created. On the other hand very often the flame wave starts very close to the tank and the interval of time between the pressure wall and the flame wall is so small that there is not enough time to check the pressure wave before the flame wave has done a great deal of damage.

One of the objects of the present invention is to control both the flame wave and pressure wave regardless of where the flame originates.

The invention is further characterized by a construction in which a pressure wave which has been able to get past the flame arrester can be brought under control without danger of. the pressure wave generating a secondary dissociation or reaction. 7

These being among the objects of the present invention, other and further objects will become apparent from the drawing, the description relating thereto and the appended claims.

In the drawing: 7

Fig. 1 is a side elevation of a tank and manifold system for use with blowpipes in which the invention is incorporated; a

Fig. 2 is a longitudinal section through the flash arrester assembly connected to the outlet'of the cylinders illustrated in Fig. 1;

r Fig. 3is a section taken upon'the line 3-4 in 8 Claims. (01. 48-192) Fig. 4 is a modification of the embodiment nlustrated in Fig. 2, and V Fig. '5 is a section taken upon the line 55 in Fig. 4.

Referring to Fig. 1, two high pressure cylinders 30 are shown as provided with shut-off valves 3| at the top thereof to which are connected embodiments of the present invention comprising a flash arrester l by means of a coupling 32. The

downstream side of the flash arrester l is connectedby pigtails manifold 35.

"At the point where gas is removed from the manifold 35, a T 36 is provided leading to a container 31. serving as a water seal which in some measure is an additional safety factor between the point of use where the gas is used and the manifold. The outlet 40 of the water seal is connected to a two stage pressure reducer M by a coupling 42 and the outlet of the regulator leads to a point of use such as blowpipes through a con: duit 43.

The flash arrester I, as herein shown, comprises a bonnet 2 threaded as at 3 to receive a mating connection. A threaded passage 4 conducts gas in the connector 32 to-a ball check 5 to compress a spring 6 of the ball check into a retainer 1 under the effective high pressure of the incoming gas.

Y The retainer 1 is-threaded into place upon the same threading receiving the bonnet 2 as at l0 and is provided with passageways 8 therethrough to permit the gas admitted through the check valve 5 to flow through the retainer 1 to a cartridge l2 held in place by a circular lip l I. With the cartridge held against a shoulder [3 provided in a housing 9 at the base of a cavity l4.

Upon the cartridge l2 .a second check valve I5 is provided setting upon a conical seat [6 formed in the housing 9 as held normally closed by a compression spring I! which is supported in a 33 to shut-01f valves 34 in a cavityjl8 upon a second bonnet 26 threaded into the housing9 as at 2|. The inner end of the second bonnet 20 and the space around the valve seat I 6 define a valve compartment 22 for the gas admitted thereto upon the compression of the spring I1 by pressure of the gas exerted on the upstream side of the check valve [5. The valve compartment 22 is in communication with the pigtail 33 through passages 24 drilled through the second bonnet 20.

P ssure exerted upon them by the incoming gas metal, sand or silicon base or stone core 26 held in place at both ends by retaining screens 21 and reinforcing reticulated plates 28 closing the two ends of a cylindrical shell 29 forming the side Wall mating with the cavity M.

The shell 29 and reticulated reinforcing end plates rigidify the form cartridge against suddenly applied pressures. The screens 21 prevent dirt or other formed material from passing However, since in some respects it is not possible through the filter or entering the filtenavhile the core 26 serves to spread out the flow of gas through small interstices to follow route channels which bring the gas into intimate contact with the material both to cool it and retard any sudden or excessive flow.

The porosity of the core 26 may be varied to some degree depending upon the size of the core and its flow area. A convenient size tohandle is a cylindrical form inch long andone inch,

in diameter with the cor'e' made of porous iron ofa density within the range of 2.50 grams] cubic centimeter to 2.85 grams/ cubic centimeter to provide a flow of acetylene of from 140 cubic feet per hour for the 2.50 density to 40.7 cubic reg per hour for the 2.85 density. If greater flow is required, the'diam'eter of the core can be increased,

the densities given or equivalent criteria being otherwise safely capable of snufiin out flames. when flash-backs occur. Density as. ratedhere is based upon'the factor {7.85 grams/ cubic centimeter as being thedensity of a solid body of iron and 250/785 being the percentage of density of the filter core. When other metals than iron are:

used, the ratio of the density of the sintered core to the density of the solid metalis maintained within-the limits rase/7.35 and 2.85/7.85.

In the event of a flash back in the manifold which results either ina flame wave or, a pressure wave moving towards the cylinders 35, the check valve'lfi will be the first to be affected. If the wave originates close to theche-clevalve, the valve 7 may not close before a substantial amount of pressure enters the cavity hi4. From this cavity itbackfires through the filter but by this time the pressures on both sides of the check 7 valve 5 are equalized gradually and the, check. valve has'more time to closehbeforeany high. pressure is effected thereagainst. Once the check.

valvesare closed there is loo opportunity for the flame or pressure waveto enter the connector 32. Theonly thing thatcan happen is that the surge. of the gas flowing from the cylinders is suddenly stopped. However, theparts are rnade strong enough to take care not, only .of the pressures present in the cylinder but also of. higherpressures expected in them.

The filter has the effect upon any backilow of gases of cooling thembelow their ignition point, and also separating them into such smallchan nels that any flame presentissnuffed out.

In the embodimentillustrated in Fig., 4 thecheck valve i5 is bypassed by.t wo smallpassage It has been found that this slight byways it-. I passing with very small passages such .as are proided by a GOto 7b drill has theadyantage in.

handling oxygen and "acetylene of relieving any dangerous shock viaves'wmch' might have a shatmaterially the passage of flame as well as pressures in event the flash arrester is used with -acetylene installations. Having thus described the apparatus and the embodiments of the invention it will be apparent from the description how the objects and processes ot the invention are accomplished.

to account fully for the improved results which are obtained by the invention, it should be understood that any attempt to analyze the theory which is believed to be responsible for these resuits is'to beconstrued not as defining a mode of operation but merely as a,possible explanatiori of certain physical and metallurgical phenomenawhich have been observed.

"Consequently, although certain preferred embodiments of the invention have been shown and described therein, it will be apparent. to, those skilled in the art that various uses, modifications and changes can be made without departingfrom the spirit and substance of the invention, the scope of which is icommensuratewith the appended claims.

What is claimed is:

V 1 A deviceoi the class described comprising a housing havinga passagefor normal movement of gaslunder pressure therethrough in opennestion, a porous cartridge in saidpassage said cartridge being. formed of sintered powderedlmetal having a density such that the ratio of fluid den- .& sity to the density of solidmetal falls within the limits 2 50/1535 and 2.85/7.85, and aback flow normallyclosed check valvein said passagupon the downstream side of said cartridge to protect it initially against Wave shock.

2. A device of the class described comprising a housing having a passage therethroughthreaded at both. ends, a porous sintered metalcartridge in said passage. approximately one inch in diameter tion, said spring being received in said recess, and

closuremeans'fcr saidone of the openings having a seat cooperating with said check valve member.

3. A flash arrester for use between a highpressure gas cylinder and a manifold comprising a housingha'ving a passage therethrough, a porous material disposed in said passage whose porosity is minute enough to snuff flame from highly cornbustible gases passing therethrough,acheclgvalve received in .saidpassagef or obstructing the back flow. of gas, 'andbleeder means for by-passing the check valve from one side thereoi to theroth er includinga blceder passagethrough said housin of, size. withina range of 60 to drill size.

4. A device of the class.. desc ri bed comprising a ho usi g. having. a passage therethrough. divided by an integral flangedefining a 'valve seat and terminated in enlarged threaded openings, a porous cartridge received in one of said openings, a retainer holding said cartridge in place, a pair of closures, one threaded into each of said openings, a check valve member cooperating with said valve seat and received within one of said closures, a second check valve member cooperating with a valve seat on the other of said closures, and means including passageways through said closures for connecting the housing to a gas cylinder and a manifold. I

5. A device of the class described comprising a housing having a passage therethrough threaded and enlarged at one end to define a cavity and threaded and shouldered at the other end to present a valve seat, a porous cartridge in said cavity,

means for holding the cartridge in place threaded 7 into said one end, and a check valve disposed into the other end to cooperate with said valve seat to obstruct flow of gas through said cartridge except in one direction, means for by-passing the valve seat including a bleed passage less than .05 of an inch in diameter, said bleed passage extending from a point on one side of said valve seat to a point on the other side thereof.

6. A device of the class described comprising a housing having a passage therethrough threaded and enlarged at one end to define a cavity and threaded and shouldered at the other end to present a valve seat, a porous cartridge in said cavity, means threaded into said one end for holding the cartridge in place including a perforate retainer and a closure having a second valve seat thereon, a check valve member cooperating with said second valve seat, and another check valve member threaded into the other end to cooperate with said first mentioned valve seat, said check valves cooperating to obstruct flow of gas through said cartridge except in one direction.

7. A device of the classdescribed for use in a high pressure connection between a high pressure cylinder and a manifold ahead of a pressure reducer, comprising a housing having a passage therethrough threaded and enlarged at one end to define a cavity upon one side of a Wall and threaded and shouldered upon thesother side of the wall to provide a valve seat surrounding a passage through the wall, a perforate element supported in the cavity in spaced relation to the Wall, a porous cartridge of sintered metal in said cavity resting against said element, means threaded into said one end for holding the cartridge in place including a perforate retainer and an adaptor having a check valve therein, a second check valve supported in the other end to cooperate with said valve seat, said check valves cooperating to obstruct the flow of gases therethrough except in one direction, and means for by-passing said valve seat comprising a bleed passage through said wall less than .05 of an inch indiameter.

8. A filter for arresting flame comprising a sintered porous metal core having a density such that the ratio of said density to the density of solid metal is within the limits 2.50/7.85 and 2.85/7.85, dirt screens at both ends, reinforcing reticulated plates holding the screens in place, and means for sealing the sides of the core from dirt.

WOODROW S. BOEDECKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,497,197 Schroder June 10, 1924 1,962,074 Hausmeister June 5, 1934 2,157,596 Davis May 9, 1939 FOREIGN PATENTS Number Country Date 23,855 Great Britain Aug. 17, 1911 744,473 France Jan. 26, 1933

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