US2608992A

US2608992A - Dual safety valve assembly

Info

Publication number: US2608992A
Application number: US729260A
Authority: US
Inventors: Clyde H Folmsbee; Jerome M Martis
Original assignee: American Car and Foundry Co
Current assignee: ACF Industries Inc
Priority date: 1947-02-18
Filing date: 1947-02-18
Publication date: 1952-09-02
Anticipated expiration: 1969-09-02

Description

c. H. FoLMsBEE ET AL DUAL SAFETY VALVE ASSEMBLY Filed Feb. 18, 1947 Sept 2, 1952 \|VLI Patented Sept. 2, 1952 d I UNITED STATES PATENT OFFICE@ `DUAL SAFETY vALvE ASSEMBLY Clyde H. Folmsbee, Bloomsburg, 'and Jerome M.

v Mar-tis, Wilkes-Barre, Pa., assignors to American Car and Foundry Company, New York, N. Y., a corporation of NewJersey Application February 1s, 1947,l serial Ne. 729,26@

' 6 Claims.

This invention relates to safetyvalves in general and in particular to dual safety valves intended for use with infiammable or corrosive gases in storage. V

Inrecent years a large business has developed in the storage of inammable gases such as butane and propane and corrosive gases such as anhydrous ammonia, chlorine, etc.V These gases are normally stored in comparatively large quantities and over a considerable period of time, with theresult that safety valves of a very dependabletype must be installed. It is necessary that these valves be lifted and tested at periodic intervals and occasionally a safety valve when so tested will develop leaks ofsuch a nature that the entire storage tank has to be discharged and the defective safety valve removed for repair. Since thesefstorage tanks are usually in populated. areas it is necessary to close'off and evacuate people from large areasduring the period that the tank is being discharged. This results in tremendous losses and inconvenience to the owner and :neighboring business and people. It isan object, therefore, of the present invention to provide a safety valve which can be removed from the storage tank and completely repaired without any significant loss ofmaterial from the tank. f s y A further object of the invention is'the provision of Va dual safety valve assembly for tanks in which Aa part thereof is built into the tank and another part can be removed from the tank- A stillA further object of the invention is the provision of a self contained safety valve which can be placed on and removed from a storage tank .while under'pressure and withoutr loss'of material from the tank.VV f

These and other objects ofthe invention will be apparent vto persons skilled in the artzfrom a studyn of the following descripticnand accompanying drawings, in which Fig. 1 is a sectional View through the improved valve assembly;

Fig. 2 is a similar sectional View but showing the safety valve inzposition for removal, and' Fig. 3 is a sectional `view taken substantially on lined-3 of Fig. 2.

Referring now to the drawings in detail i-t will be seen that the dual safety valveassembly is made up'of a removable partiA and a part B which is permanently built into the tank and can not be tampered with except when-the. tank is completely emptied and cleaned. The shell of the storageftank is indicatedat 2 and 'this shelluis pierced to receive aV tubular nozzle 4 permanently 2 Y welded or otherwise attached as at 6 to the shell of `the storage tank. This nozzle has welded thereto adjacent its lower or inner end aring 8 and adjacent its upper end is welded a ring l0. The lower inner surface of the nozzle is beveled as at I2 and this merges into a machined surface I4. -The upper end of the nozzle has itsinterior surface machinedV as at I6 and a small notch or groove I8 is cut so as to provide a vent later to be referred to. Y

The lower ring d carries a plurality of vbolts or Asimilar means 20 which are threaded into the ring and welded against movement as at 22. These bolts or similar means provide a thrust surface for the lower ends of spring 24, the upper ends of which bear against a stop valve plate 26 guided for movement on the bolts 20. The stop valve plate is provided with a beveled seating surface 23 adapted to contact with the beveled seating surface I2 of the nozzle. The stop valve is also provided with a vertical extension grooved as at '3G to receive a resilient sealing ring 32 of circular cross-section, which ring is adapted to lightly'engage the machined surface i4 to effec'- tively seal against leakage. f

The safety valve consistsof a body 34having anges 36 adapted to be clamped onto the upper end of the nozzle by means of bolts 38 which extend through a'clamping ring 4i) and into the nozzle ring Ill. The clamping ring as shown is provided with a discharge stack 42 of any suitable length. VThe safety valve body `is pierced to provide a passageway 44, rat the upper end of which is provided a valve seat 46 adapted to engage a similarly formed seat 48 on the valve'stem member. The valve stem member is provided with'w-ings' guiding it in the body opening and the

seats

46 and 48 are held in intimate Contact by 'means of a spring 52 bearing at one end on the valve body and at the other end on cage 54 vadjustably held on the valve stem 56 by nuts or other means 58. In order to prevent any leakage past seats 4B and 48 a cap member 60 is clamped onto the valve by means of the nut or other means 62 and this cap is grooved to receive a resilient ring 64 of circular cross-section which will prevent any leakage past the stem extension of the valve. A similar ring S6 of resilient material and circular crosssection is received in a groove formed in the cap and this ring engages a portion of the body to prevent any leakage between the cap and body. In this manner leakage of material through the safety valve is prevented except when the lvalve should open 'or pop under excessive pressure. The outer surface of the valve body 34 is grooved as at 68 to receive a circular ring 10 of circular cross-section and resilient material which is adapted to engage the machined surface I6 of the tank tube or nozzle and thus effectively prevent leakage between the safety valve body and the tank tube or nozzle. A tubular extension'M is welded or otherwise attached 'tov the inner surface of the valve body 34 and is of sufficient length as to hold the stop valve assembly 26 from engaging the lower end of the tank tube or nozzle when the Ysafety valve is in position. In order to permit ready entrance of material from the tank intothe tubeld semi-T.

circular openings 16 are formedvinthelower-end; thereof.

When the parts are in the position shown in Fig. 1 the safety valve withits extensionwll.

maintain the stop valve 26 in its full open position or at least in such a position that an area for passage of material into tube 'i4 is provided whiehis equal to or greater than the total disdishargearea past the safety valve when open or p opped. Ifgfor any reason the safety valve should (develop a slight leak ory be ldamaged in any-way-it, .can beremoved by rotating nuts 80 on bolts. ,38gI thereby permitting the internal `tank pressure-tolift theisafety valve in the nozzle. iis5the-.nu-ts-A till'` are backedeoif of the bolts the safety valvewillfollow with all leakage `prevented by the r-esilient ring 10. When the safetyfvalve hasbeen; raised sufficiently the seating surface 28 ofthestopvalve will engage the seating surface IZvof :the tanktube rornozzle and further movementofg thestop valvewill be checked. Prior to thisitime. however,- theecircular ring 32 of resilientmaterial willy have-entered the` nozzle and engagedtheA machined surface I4 thus sealing the :1W/er1v end. of the, tank tube or nozzle. The stopvalvethengbecomes a thrustmember pushing thesafety--valveupwardly with itsmotion controlled.: by :the rate at; which' the nuts 80 are backedpf the bolt.- Any pressure trapped within the; tanktube'orgnozzle will Vcontinue to lift the valve after the -stop valve-has become seated. As soon, however, as the resilient ring 'Illhas passed thellvower enclofv groove I8 this trapped pressure wllgbelvented; andthe nuts 8l) may be thenfully removed without danger. As soon as these nuts are removed thefstack audits. ringllly be removedgandi the; ent1e safety valve removed f0.1* inspection; and. necessary repair- After inspectionand'repair the 4.safety valvel may be again insertedjnto the tank 4tube vor nozzlewith the resilient;Y ring-I8 sealing` against any escape of material. between the. nozzleand valve body. Forcing; of ithesafety valve into its final position will be-accomplished by'tightening the nuts 8D o ntothebolts 38, thereby forcing the safety valve intdzits nal position'during which time the stop yalveffwillbe moved to its open positionias lshown in VEiga'. 1l

lroimtheprecedingit will be seen thatthe stop valve isattachedV to the tank tube or nozzle; on the inside of .thetank andprevents escape ofgas orfmaterialh from the; tank when the safety-valve iseremoved.-` It willalsobe apparentthat the safety-valYe-can be removed, repaired and reinserted-inthe tube or'nozzel without any danger or,loss-of material other thanvtheloss of'the Small amount ofmaterial which is trapped withingthestanktube or nozzle at the time of closing thefstopvalvey 26. Whilevthe construction has heendescribed more or-less in Vdetail with specic reference tothe drawings. it will be obvious that alightmodifications; may-be made without de- 4 parting from the scope of the invention as defined by the following claims.

What is claimed is:

1. A dual valve construction comprising, a nozzle structure, a pressure relief valve assembly having atleast portions thereof located within the nozzle structure, means, retaining said pressure relief valve assembly portions in said nozzle structure and adapted to allow removal of said assembly, sealing means interposed between said assemblyv and nozzle structure to prevent leakage therebetween during at least part of the removalmovement of said pressure relief valve assembly. a stop valve carried by said nozzle structure adjacent the inner end thereof, an extension on said pressure relief valve assembly holdingk said stop valve in spaced relationship to said nozzle structure when said relief valve assemblyy is retained in said nozzle structure by the retaining means, and a sealing means adapted to, engage saidxnozzle structureA andgstop, valve toprevent leakage therebetweenA following; partial removal of` said pressure, relief valve assembly.

2. The structure of claim 1 characterized in that, said last namedseal-ing .means isrcarried; in agroove formedson said stop valve andis oft sub.- stantiallyr circular cross-section;

3; The; structure of f claim 1 characterized' in that,I saidl nozzle structure. isfprovided with vent means to allow escape of pressure trapped vwithin the.,nozzle structure 4between said sealing. means during removal, of said pressurel relief valve-ass embly.l

4., A dual valvefconstruction comprising, a nozzle, a pressure relief valve assemblyy connected to. the nozzle .but removable.A therefrom, an extension carried Vby said assembly` andfextending into the nozzle to adjacent theremote end thereof, av stopvalve Acarried by 'said'remote end of the nozzle and normally held in spacedrelation thereto ,by'said :extension when said relief valve assembly is fully connected to the nozzle structure, and seal meansoccupying the space between said pressurereliefVA valve assemblyI and nozzle `and between said'stop valveand nozzle to prevent leakage-of `matter past said valves during connection and `removal ofthe relief -valve assembly.

. 5. A duall valve construction comprising; a nozzle, a pressure relief valve assembly located withiny the nozzle'but removable-therefrom, an extension carried by said assembly and extending to adjacent the remote end of the nozzle,a stop valve carried by said remote vend ofl the nozzle and held in spacedrelation ther-etc by said extension, and seal means occupying the space between said pressure relief valveV and'nozzle and between said stop valve and nozzle to prevent leakageof matter past said valves, Vsaid seal means and valves being so constructedancl arranged that one at least'is always in constant sealing engagement with said nozzle during removal of said pressure relief valve assembly.

6., Adual, safety valve-construction comprising a tubular fnozzle. structure, af-,pressure relief valve assembly removably clamped ontoy said nozzle structure adjacent one endi thereof, said-relief valve structure.: including. a body portion positioned in said 'nozzle-.when said parts are assembled, said vbody portionzbeing-formedwith an annular-groove, a .circular vring ofl circular -cross section formed of resilient materialy positioned'in said :groove and lcontacting the inner 1 surface of said tubular structure, astopvalve carried bythe other: end; of saidltubular structure, said@ stop valve being formed with a vertical annular extension for movement into said nozzle structure during seating lof said valve, said extension being formed with an annular groove, a circular ring of circular cross-section formed of resilient material positioned in said groove for contacting the inner surface of said tubular structure, spring means normally urging said stop valve toward its seat on said nozzle structure, and means depending from said relief valve body portion for holding said stop valve from its seat against the tension of said spring means.

CLYDE H. FOLMSBEE.

JEROME M. MARTIS.

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

5 UNITED STATES PATENTS Number Name Date 259,109 Duchemin June 6, 1882 889,952 McGinley et al. June 9, 1908 l0 2,288,565 Green May 31, 1940