US1340832A - Safety-valve - Google Patents

Description

l. G. LANNJNG.

SAFETY VALVE.

APPLICATION FILED DEC. 2o, 1917.

1,340,832. Panzf May 18,1920.

2 SHEETS-SHEET I.

ya' "tja 1.' G. LANNING.

SAFETY VALVE.

APPLIS/THON FILED DEC.2Q,191Z.

Patented May 18, 1920.

2 SHEETS-SHEET '2.

JOHN Gr. LANNING, OF DETRGIT, MICHIGAN.

ySAFETY-varare.

Specication of Letters Patent. l

Patented May 1 8, 1920.

Application led December $50, 1917. Serial No. 208,156.

To all lwhom t may concern Be it known that l, JOHN G. LENNING, citizen of the United States, residing at Detroit, l/Vayne county, in the State of Michigan, have invented certain new and useful Inventions in Safety-Valves, ofwhich the following, together with the drawings filed herewith and referred to in this specification, constitutes a full and complete description.

My invention relates to improved valveseat mounting construction designed to maintain the seat in its true and original form by battling the distortive tendency of structurally arising strains to which in operation it otherwise would be subjected.

The present improvement has particular reference to a protective means for mounting the annular seat of a safety valve of the lift type, wherein as customarily constructed, a liftable disk is held against an annular seat by the constant load of a -spring or weight,hthis disk in operation heilig exposed to a fluid confined under pressure so that rise in the intensity of said pressure to a predetermined point overcomes the spring or weight load and lifts said disk to open the valve.

Under normal operating conditions of such valves the relatively opposed spring closing-pressure, and fluid openingaressure gradually approach exact equality as the designed critical pressure is reached; and obviously, therefore, their differential resultant--(the force acting to hold the disk against its seat) is actually very small at pressure approaching that critical amount so that attainment of Huid-tight valve closure then depends entirely on continuance of the disk and seat in their designed conformity for true fluid-tight alinement and engagement under slight force.

The valve seat, however, must be carried by some valve base portion either as a part of-or attachable to-the boiler or other container of the governed fluid; and the troublesome effect has heretofore been encoutered that mechanical clamping, screwmounting, or other method of securing the seat carrying structure to this base portion, or of said base portion to the boiler springs or deforms the valve seat so that after assemblage the latter fails of fiuid tight alinement with the disk.

Moreover, in cases of safety valves employed for limiting the rise of pressure intensity in fluidsV of high temperature such as steam, widely varying temperature effects are encountered whichg set up unequal stresses in the boiler and result in structural strains which, in seat-mounting construction'Y as heretofore known, may readily be transmitted to the valve seat through its support connection with the above mentioned base portion. Obviously therefore the grinding of disk and seat into true conformity after assemblage is of little avail since these temperature effects are constantly present in operation.

My invention provides simple and practical means whereby 'the valve seat is constantly and effectively protected from deformation by such causes as have above been described; and thus whereby the desired accuracy of operation and the durability of safety valves may be secured by entirely preventing wasteful and impairing leakage thereof.

Various expedients have been suggested in the old and well developed art of safety valves for insuring constant and true form of valve seat therein, by protecting that portion of such structures againstsuch distortive strains as are abovevmentioned, but so far as I am aware the construction and means so devised by me are broadly novel. The broad principle in construction which I utilize for protecting the valve seat resides in providing said seat with a supporting structure that includes preferably, but not necessarily, only two simple and distinct main portions of a requisite difference in relative rigidity,-the more rigid, and operatively rigid of said portions carrying the valve seat, and the less rigid, or operatively iieXible of said portions, connecting said first portion to the rigid mounting base, or support frame,

for the valve mechanism. It has, in general, been recognized by others that a valve seat-supporting structure having portions of relatively different rigidity tends to bafiie the transmission of strains through said structure to the seat and thus to protect the latter from deformation 'in fact certain, but comparatively ineffective, structures have been devised in attempts to produce a practical embodiment of this idea.

But the means which I have devised for availing of the principle above described are distinctly different from those heretofore proposed and may be embodied in a simple formA of practical construction wherein the greatest benefits to be had from the underlying principle become most effectively operative.

My improvement, briefly expressed, specifically contemplates the provision of a valve'seat-supporting structure having the two portions mentioned above, in which the difference between the greater rigidity of the immediate seat-carrying portion and the less rigidity of the support connection extending between the same and the valve base portion is so great that the former of said portions cannot be sprung, warped, compressed, or otherwise changed in shape (to affect the conformity thereof with the valve disk) by any operative deformation of the support connection, the latters relative degree of flexibility on the other hand enabling it readily to yield in response to strains imparted thereto through. its, connection with the rigid valve base portion.

rlhe preferred construction which I have herein chosen for illustrating my invention employs as convenient forms for the non-yielding seat-carrying portion and for the yielding portion supporting Ythe same, respectively, a thick-walled, tubular shank of considerable axial extent, vand a thin, annular flange or diaphragm, preferably integral therewith, and I may arrange these portions as an integral bushing adapted to be screw-seated, clamped, or otherwise rigidly 'secured at the outer peripheral portion of the said flange to the heretofore mentioned 'valve base portion.

It will be clearly understood, from the above description, that when the termsV rigid, operatively rigid, or operatively incompressible are hereinafter used to designate a requisite structural quality of the immediate seat-carrying structure, l mean, by such terms, not a structure that can, and does, operatively yield, compress, or change form, but a seat-carrying structure of a hardness and rigidity that is designed to, and does, enable it to retain its original structural form under all forces tending, in operation, to distort it.Y

A further and important feature of my present invention is the provision of meansv for relieving the yielding support connection or annular,diaphragmV of the stress or lshock due to theV blow-down action, or other excessive thrust, of the lifting valve disk, which latter in the particular form shown is heavily tensioned against the seat g-the term blow-down being the technical phrase in the practical art descriptive of the automatic closing move-v ment of the valve disk.

Structural embodiments of theY novel principles of my invention are disclosed in preferred form in the followingv description and in the accompanying drawings wherein;

Figure 1 shows, in plan View, the lower portion of an assembled safety valve structure incorporating my improved mounting' for the valve seat, and is taken-in section on the plane 1-1 in Fig. 2.

Fig. 2 is a vertical section through the assembled safety valve structure on the plane 2*@ in Fig. i.

Fig. 3 shows a different way of securing my improved valve seat structure in place.

Fig. 4 is a plan view of a modified form of valve seat structure with associated parts for mounting the same. I Y

Fig. 5 is a central, vertical section ytaken on the plane 5 5 in Fig. 1.

Fig. 6 shows a further modified form of valve seat structure, and a still ydifferent mounting construction for the same.

Each part when appearing in different views of the drawings bears the same reference numeral and is thereby designated in the following description.

The assembled safety valve structure that I have herein disclosed to illustrate my invention is of a type Awell known in the art. In Figs. y1 and 2, the outer support case 10 is adapted to be bolted, or otherwise mounted Y as usual, on the boiler or other container (not shown) of the steam or other fluid,

against excessive pressure of which the safety valve is designed to guard.

My improved valve seat structure appears at 12 as a separate and demountable screw bushing, though it need not necessarily be so constructed. An internal bevel 14 at the upper, inner edge of this bushing forms the stationary valve seat that coperates in the usual manner with a correspondingly beveled edge of the lifting valve disk 16, to open and close communication between the container-connected chamber 18 and the exhaust chamber 20 through the annular passage 22, which passage may be varied in size by screw adjustment to different vertical heights of the blow-down7 ring 24:, carried at the threaded top of my improved valve seat bushing 12, and formed in a well-known ceive cap dome 38 that spans an upper opening in the support casing 10. Thiscap dome, in the form shown, has a central, and downwardly-extending, cylindrical portion 40 that cooperates telescopically with an upper cup extension 42 of the disk 16, to check en trance of the exhaust fluid to the dome chamber. The above-described safety valve mechanism, as before stated, is in its general features, well known in the art with the exception of the novel structure constituting the mounting for the stationary valve seat 14, in which structure principally resides my present invention.

The valve seat bushing 12, before mentioned, is mounted above the lower opening 44 in the support case 10, which is counterbored and threaded internally at 46 to rea correspondingly -threaded outer ring portion 8 of said bushing. rThe shank portion 50 of this bushing is connected to, and supported from, this outer threaded ring portion 48 by a relatively thin, annular diaphragm web 52. The various portions of the valve seat bushing 12, above-described, constitute, in the form shown, an integral casting, although they need not necessarily be so made in practising my invention, and the diaphragm portion 52 may be of suiiicient strength to withstand pressure of the fluid in the container-connected compartment 18. 1t is an important, though not essential, feature of the arrangement disclosed, that the end of plunger spindle 32 bears upon the floor of the well compartment 26 in valve disk 16 at a point lying substantially in the same plane with the diaphragm web 52. rFhis results in rocking movement of the shank portion 50 (as caused, for instance, by strains arising in the yielding web 52) producing the least possible disturbance both of the designed (3o-axial alinement of the thrust bearing points for the spring 30 and of the said point in the central compartment of the valve disk 16 upon which the end of the spring-pressed, plunger spindle 32 bears; and of the tension of the valve closing spring. It will be noted that the outer, threaded, ring portion 48 of the bushing 12 screws to a seat at 54 on the bottom of the counterbore above-mentioned, and that sufficient clearance is provided between the lower end of shank portion 50 and a further counterbored rabbet 56, of smaller diameter, to insure seating of the ring portion at said point 54. This axial clearance, however, is preferably suiiiciently small to permit reinforcing abutment of the said end of shank 50 against the bottom of rabbet 56 if the force of the blow-down impact, or springcaused closure of the valve, is great enough to exceed the resistive resilient strength of the diaphragmatic supporting web 52. Other equivalent forms of protective reinforcement, could, of course, be as readily provided, arranged if preferred as means operating on the disk 16 or plunger rod 32 so as to limit the intensity of downward thrust that can be exerted thereby upon the valve seat 14 or if the web 52 be made sufficiently rigid to care for the maximum stress to which it could ever be subjected no such reinforcement would be necessary. It will be obvious, however, that by providing such reinforcement, 1 am enabled to use a more flexible web connection than would otherwise be possible. The rabbet 56 is formed as a depression in the iioor of the counterbore 46 merely to assist in centering the clamp-secured form of bushing illustrated in Figs. 3 and 5.

F rom inspection of the drawings, it will be'obvious that the shank portion 50 of my improved valve seatA bushing 12 is compara tively rigid and solid as related to the com-- paratively weak and yielding diaphragm portion 52, and that, consequently, mechanical strains imposed upon the support case 10 by tightening up of the mounting bolts in assembling (which strains, in case of steam boiler installation, are often augmented by later changes in' temperature) and resultant deformation of the outer ring portion 48, will be absorbed in the relatively yielding diaphragm portion 52 of the bushing 12, and not transmitted to the shank portion 56 to 'result in deformation of the beveled seat 14. My improved construction thus completely avoids any local warping or disturbance of requisite alinement of said seat relative to the disk 16, such as commonly results from strains of the character above described in valve seat structures of the ordinary type. The threaded outer ring portion 48 may be castellated as shown at 58 to provide means for engagement of a wrench in assembling and dis-assembling.

1n Fig. 3, in place of the threaded, outer, ring portion 48 for securing the bushing 12 in place, merely the annular foot edge 60 is provided and adapted to be clamped in place by a separate, threaded and castellated lock ring 62.

1f it be desired further to increase the difference between the relative exibility of the diaphragm portion 52 and the relative rigidity of the shank portion 5G, 1 preferably increase the rigidity of said shank portion by forming it with an exterior flange 64 and with bracing webs 66, as shown in Figs. 4 and 5.

1n general it will be seen that the diaphragm or web, being exposed fully to the pressure of the contained fluid, must be of such strength as to have a proper factor of safety. It will be obvious, however, that the best results are secured in the practice of my invention by making the seat carrying portion of the greatest possible rigidity and by making the diaphragm or web portion as yielding as practicable.

ln safety' va ves such a construction, it will be seen, affords a safety element in the diaphragm, which may itself rupture in the case of vitally detective operation oi the valve. lnthis connection, also, it should be noted that, with the valve properly operating, the opening litt of the disk at the designed intensity oi lluid pressure limits the maximum thrust to which the diaphragm or web 52 can be subjected by such fluid pressure thereon, because of the arrangement whereby lsaid disk and said web are always exposed to the same body ot fluid.

l may, as shown in Fig. 6, obtain increase in rigidity of the shank portion 50 relative to that ot the web 52 with a lessenet. axial length of such shank between the valve seat la and the supporting diaphragm portion 52. ln such case the shank portion may be made to retain substantially its same overall length, however, by extending downwardly through the opening 44 as shown at 68,- thus to len-d rigidity to the seat carrying portion and to guide the radial wings of the valve disk 16 in the usual manner. lt will be noted that no reinforcing abutment is here present to relieve the diaphragm 52.

The preferable forms ot construction, however, are Vshown in Figs. l, 2, 3, a and 5 ;--the form shown in F1 g. 6 not being desirable where the valve structure when assembled andplaced in service is subjected to severe piping strains or changes in temperature. Y

Other equivalent modiicatiens will readily suggest themselves to mechanics skilled in the art, and obviously my invention may have useful application in types loil valves other than are herein shown ,-'lor instance, in a valve wherein a disk is held close-d to its seat by differential fluid pressure, or other means, instead of being subject to the constant closing thrust oil a spring, weight. l therefore do not wish to limit the scope or my invention to the speciiic forms thereof which l have herein disclosed merely for illustrative purposes, but what l claim as new is:

l. ln a valve mechanism for controlling` fluids at pressure and including an operatively rigid, orifice closing, liftable valve disk with governing means yieldingly pressing the same axially against an oriiice-surrounding` seat, thereby to close and permit opening of the valve, in combination; a rigid and operatively incompressible, tubular member carrying said seat in a position to receive said disk in duid-tight engagement therewith; and a relatively flexible and less rigid, annular, support web diaphragmatically disposed transverse the axis of said -member and connecting the latter with a holding structure therefor.

2. ln safety valve mechanism for automatically controlling the storage of fluid at designed pressure, in combination; an operatively-rigid valve-closing disk arranged to be pressed by yielding means axially against a valve seat surrounding an orifice for the stored fluid, so that the eiiective valve-closing pressure between said disk and said seat is gradually overcome as-the pressure of the stored fluid on said disk increases; a rigid and operativelyincompressible tubular member carrying said seat in a position to receive said disk in fluid-tight engagement therewith; and a relatively ilexible and less rigid annular support web diaphragmatically disposed transverse the axis of said member And arranged to connect the latter with a holding structure-therefor.

ln safety Avalve mechanism for auto-- matically controlling the storage of fluid at designed pressure, in combination; an operatively-rigid valve-closing disk arranged to be pressed by yielding means axially against a valve seat surrounding an orifice for the stored luid, so that the effective valve-closing pressure between said disk and said seat is gradually overcome as the pressure oi the stored iluid on said disk increases; a rigid and operatively-incompressible tubular member carrying said seat in a position to receive said disk in duid-tight engagement therewith; and a relatively flexible and less rigid annular/support web diaphragmatically disposed transverse the axis of said member and arranged to connect the latter with a holding structure theretom-said member being of suhcient rigidity relative to said support to operatively resist deformation by any stress operatively set up in the latter through deformation of said holding structure, thereby to prevent deformation of the valve seat. 4f, A self-closing lift-valve embodying i combination with an axially movable disk having yielding means acting thereon to hold said disk against an annular seat; an operatively rigid and non-yielding tubular shank carrying said seat vat one end thereof; a relatively yielding flexible support ilange for said shank disposed transverse the axis thereof as an annular, diaphragmatic web; and a rigid valve base having circular opening therein and carrying said flange in a position to support said shank concentrically with said opening; the said flange and said shank beinfT of such relative rigidity that t ie latter cannot be compressed by, nor llex responsively to, operative deformation arising in the former. Y

5. Asafety valve having in combination with a support frame; an annular valve seat formed at the mouth of a cylindrical orifice tor the confined Huid; a lifting valve disk yieldingly tensioned against said seat; and a seat-carrying structure formed with a relalOl lOl

lll

lli

tively non-yielding and relatively rigid tubular shank constituting the said fluid orifice and a relatively resilient support flange surrounding said tubular shank disposed transverse the axis thereof as an annular, diaphragmatic .veb and arranged at its outer circumferential portion to ye carri/d by the support frame ;-the said flange being nisposcd as a retaining ivall for the fluid and thereby subject to the same specific fluid pressure said disk ,-Yvher `y the maximum operative intensity of said pressure agains said flange is determined and lim ited by the fluid-pr saire-opposing, yielding` tension of said disk against its seat.

6. ln a self-closing lift-valve including an axially movable valve disk having means acting thereon yieldingly to thrust said disk against an annular seat, in combination with a valve mounting structure having an opening for passage of the valve-controlled fluid, an integral seat-supporting bushing structure formed with an operatively rigid and incompressible tubular shank portion carrying said seat at one end thereof, a substantially rigid ring portion spaced apart from said shank portion and adapted to be detachably secured to said mounting structure so as to surround the said opening therein, and a relatively flexible diaphragmatic portion circumferentially connecting With both said shank portion and said ring portion yieldingly to support the former eoncentrically vvith the latter.

'i'. In a self-closing lift-valve including an axially movable valve disk having means acting thereon yieldingly to thrust said disk against an annular seat, in combination with a valve mounting structure having an opening for passage of the valve-controlled fluid, an integral seat-supporting bushing structure formed with an operatively rigid and incompressible tubular shank portion carrying said seat at one end thereof, a substantially rigid ring portion spaced apart from said shank portion and formed to be detachably secured to said mounting structure so as to surround the said opening therein, and a relatively flexible diaphragmatic portion circumferentially connecting With both said shank portion and said ring portion yieldingly to support the former concentrically with the latter; the said shank portion and said diaphragmatic portion being of such relative rigidity that the former cannot flex responsively to, nor be compressed by, operative deformation of the latter.

8. In an automatic safety valve having a fixed seat for a valve disk axially movable relative thereto, and a seatsupporting structure arranged to yield to the pressure of said disk when the latter is thrust against said seat to close the valve, in combination; a fixed stop positioned to be engaged by said structure, thereby to limit its yielding movement as caused by the pressurev of said valve disk.

9. ln a safety valve, the combination With a movable lifting valve disk, a substantially rigid structure carrying a seat for said disk, and a relatively yielding but fixed connection arranged to support said structure; of a reinforcing abutment normally spaced from a cooperative portion of said structure and so disposed relative thereto, as to be engaged by said portion upon diskcaused abnormal displacement of said structure, as permitted bythe yielding of said support connectiong-thereby to prevent excessive distortion of said connection consequential to such displacement.

10. ln a safety valve, in combination; a lifting valve disk; an annular seat therefor; yielding support for said sea-t; avalve closing spring acting to thrust said diskA against said seat so that the thrust of said spring is borne by said support; and means arranged automatically to relieve said yielding support of the thrust of said spring by intercepting said support when said thrust acquires a predetermined intensity.

11. In a safety valve including a movable valve disk tensioned against a fixed annular seat structure to close the valve, in combination; a yielding mount supporting the seat structure against the thrust of said disk and designed Ythrough self-deformation to protect said structure from strains imparted to said mount, and thereby adapted to per# mit slight mobility of the seat structure as a Whole; and means arranged to act on the scat structure to limit said mobility thereof, y

thereby to protect said yielding mount against excessive thrust of the tensioned valve disk.

12. In a safety valve including a movable valve disk tensioned against a fixed seat structure to close the valve; in combination; a yielding mount supporting the seat structure against the thrust of said disk and designed through self-deformation to protect said structure from strains imparted to said mount, and thereby adapted to permit slight mobility of the seat structure as a Whole; and an interceptive abutment spaced apart from said seat structure as the latter is normally positioned when supported solely by its said yielding mount, but arranged through engagement with said structure to limit said mobility of the latter so as to oppose the thrust thereupon of said tensioned valve disk when such thrust becomes excessive.

13. In an automatic safety valve having a fixed annular seat for a movable valve disk and a hollow cylindrical seat-supporting structure carrying said annular seat at one end thereof and yieldingly supported so as to sink slightly under'the pressure of means acting on said disk to close the valve,

' in combination; a circular abutment slightly spaced from the end of said cylindrical structure opposite its said seat-carrying end, thereby to be circumferentially engaged by said stiucture'to limit the sinking movement thereof as caused by the pressure of'said means.

14:. In a valve structure of the type including an annular valve seat formed at the mouth of a cylindrical orifice, and a c0- operating lifting valve disk arranged for movement axially ofV said orifice to and from said seat; an integral bushing structure comprising said cylindrical orifice and including a hollow cylindrical shank portion carrying the valve seat; a -substantially rigid outer portion for detachably mounting said bushing on thev valve structure; and a relatively less rigid annular Web disposed ina transaXial plane and connecting said two portions to support the former approximately centrally of the latter,-sad shank portion being formed With reinforcing ribs extending longitudinally thereof approximately from said seat to the point of connection of said supporting Web.

15. Inl a safety valve, in combination; an annular valve seat; a valve disk member mounted to be axially movable to and from said seat and having a Valveclosing-thrust receiving portionV axially distant from the valve disk; a seat-'carrying structure formed in one portion-as: a rigid, tubular shank i surrounding the thrust-receiving portion of said member and carrying the valve seat atk one end thereof, andl formed at another portion as a relatively yielding flange surrounding said yshank in a transaXial plane and connecting the same with a'rigid means of support therefor; and a valve-closing plunger-rod tensioned for longitudinal movement' and arranged to bear at one endy thereof on said thrust-receiving portion of the valve Ydisk member, thereby yieldingly to hold said valve disk against said seat the contact of said plungerrod With said Vmember occurring centrally of the said tubular shank and substantially in the transaxial plane of the said yielding iiange.

Y 16. In a self-closing lift-,valve including an axially movable valve disk having means acting thereon yieldingljy to thrust "said disk against an annular seat, in combination'ivith a valve mounting structure having an opening for passage of the Valvecontrolled fluid, an integral seat-supporting bushing structure formed With an operatively rigid and incompressible tubular shank portion carrying said seat at one end thereof, a substantially rigid ring portion spaced apart from said shank portion and formed to be detachably securedv to said mounting structure so as to surroiuid the said opening therein, and a relatively flex- Y tion and said ring portion yieldingly to n support the former concentrically with the latter, the said mounting structure being formed to present a circumferential re-inforcing abutment for said tubular shank portion, slightly spaced therefrom in the position said shank portion is normally carried by said diaphraginatic portion, but adapted to intercept the same, When said shank portion is displaced from its `said position by the thrust of the valve disk thereon and against the resistance of the yielding diaphragmatic portion. g f

Signed at Detroit, Michigan, this 7th day of December, 1917. I v

JOHN G. LANNING.

Witnesses: Y EDWARD A. SMITH,

WILLIAM G. COME.,

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