|Publication number||US1816293 A|
|Publication date||Jul 28, 1931|
|Filing date||Sep 30, 1925|
|Priority date||Sep 30, 1925|
|Publication number||US 1816293 A, US 1816293A, US-A-1816293, US1816293 A, US1816293A|
|Inventors||Oberhuber William F|
|Original Assignee||Oberhuber William F|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (16), Classifications (14)|
|External Links: USPTO, USPTO Assignment, Espacenet|
` July 28,4 1931. w. F. OBERHUBER j METHOD OF MAKING H=IGH PRESSURE STEAM JOINTS Filed Sept. 30, 1925 v l 3 Sheets-Sheet l July 28, 1931. w. F. OBERHUBER V METHOD OF MAKING HIGH PRESSURE STEAM JOINTS Filed sept. 30, 1925 s sheets-sheet July-28 1931. w. F. OBERHUBER METHOD OF MAKING HIGH PRESSURE STEAM JOINTS Filed sept. so, 1925 s sheets-sheet 3 d i6' 2a' In@ A /M/M f 0,4%, mw, zw, W. ,f MWJW Patented July 28, 1931 UNITED STATES PATENT oF-FICE WILLIAM F. OBERHUBEIQJOF DREXEL HILL, PENNSYLVANIA. I
MEfrHon or :ruime HIGH yPRESSURE STEAM .rox-Nrs Applicata@ mea september 30,1925'. serial No. 59,462.
My invention relates to joints for piping carrying high pressure vsteam and Vthe like;4
that is, to pipe joints that areadapted lto stay tight under very high" fluid pressures within 6 the pipe.
A purpose of my invention 4is to provide a joint that willautomatically tighten with increasing pressure. l
A further purpose is to provide a joint 10 well suitedto retain fluids having high pressures or subject to widely variant temperatures. j
A further purpose is to provide a pipe joint that will take up and stay tight under 15 the longitudinal strains of compression and sealing against both flanges by annular spring contacts on the diaphragm,A using the lateral` spring -of `the body of the diaphragm or und-e'rcutting beneath the annular contactsJL to insure good contact and its maintenance.
A further purpose is to have the bearing surfaces of'mating 'high pressure vflanges com prise' spaced zones with .deep grooves Ain bey tween and to concentrate theicontactingpressure between the flanges at the inner'rims' ofl the Azonesby outwardly and rearwardly re- 40 lieving the `Zones from their inner rims.
A further purpose is tomake a flange hav.- ing spaced zones of bearing surface of resilient materiahsuch as stee'lgand to lundercutthe inner rim of ,each Zone,` thereby better adapting the zone of Contact to accommodate itself vto irregularities of a mating flange and tolongitudinal strains, increasing its bearing pressurer when `the fluid pressure within the ,pipe increases.V l
'A further purpose is to provide a diaphragm for insertion between mating plain faced pressure flanges with bearing surfaces having spaced zones of contact oneachside, undercut at the inner rim of each zone, and each zone relieved somewhat from its inner rim outwardly.
Further purposes will appear in the specilication andin the claim. i
' l have .elected to show a few only of the forms in which my invention may be applied but have selected froms vthat well illustrate the principles involved and which are practical and elicient in operation, A
Figures l and 2 are side 'elevations o f screwflange pipe joints applying respectively different forms of my invention.
Figure 3 is a longitudinal .section` illustrating my invention in diaphragm formv applied between flanges that are integral' with pipe'sections. j y A j Figure 3a is a section similar .to Figure 3 but showing another application. y
Figures 4 and 4a are fragmentary en! larged sections of al portion of av structure seen in `Figure l and a. slight modification thereof, the section being'longitudinal with respect to the pipe. t. j
Figures '5, 6 and 7 are transverse'sections corresponding generally to linejff? of Fig# ure8 showing different forms of diaphragm for sealing between facing flanges for vother surfaces. i
,Figure 8 is an elevation which" may be j I either front or drear elevation of the dia-y phragm whose section .is shown iirF'igure 7,
FiguresS and 9a are enlarged fragmentary sections corresponding to a portion of Figures and 5 but omitting the iholding means. p n n Figure 10 is a' fragmentary transverse section of ,a pipe ,and flange to which my 'invention is applied, the entire .flange being integral with .the pipe.
AFigures 1l and 12 are central verticalsections showing valvesto which my inventionis applied.
Figure '13 isa front face view 'of oneof the kflanges seenfin` Figure 11. or Figure l2.
`Figures 14, l5, V11G/andr4 '17 are fragmentary enlarged sections corresponding the first two generally with Figure 11 and the last two generally with Figure 12 but differing 14 from 15 and 16 from 17 in detail.
Figure 18 is a longitudinal section of an expansion fitting connected to pipe by two of my flange joints.
In the drawings like numerals refer to like parts in all figures. Describing in illustration and not in limitation and referring to the drawings It is diflicult to maintain the joint of pressure pipe lines tight where the pressure is high, the temperature widely variant or the line subject to bending strain. The increase in pressure of steam and liquids such as oils has increased this difficulty.
My invention is directed primarily to correct this evil, and I have endeavored to build a joint with the following characteristics That it uses a standard plain-face flange as one of its members, or, where a. gasket is used, two plain-face flanges; that it will accommodate itself automatically to normal irregularities of the standard flange or flanges; that it reduces the requisite strain upon the flange bolts; and that it will accommodate itself and stay tight under fatigue lengthening of flange bolts and under the compression and expansion strains normally present in pressure lines or due to temperature changes. Some of my forms also desirably tighten with increase of pressure Within the pipe.
In the form shown in Figures 1, 4 and 4c end flanges 10 and 11, which would normally be Welded upon adjoining pipe sections 12 and 13, are held pressed tightly together by suitable bolts 14, only a few bolts being shown in the figure.
A succession of annular grooves 15 in the bearing surface of one of the flanges 10 divides the face of the flange into a succession of annular teeth 16, 16 and the ends 1T, 1' of these teeth afford spaced annular surfaces that support the entire compressive reaction between the flanges.
The surfaces 17, 17 upon the ends of the annular teeth are preferably somewhat relieved or ta ered outwardly, that is, cut away somewhat rom near the inner rim 18 toward the outer rim 19. This relief outwardly of the ends of the teeth tends to concentrate the entire presure between the flanges upon annular lines 20 (Figure 4) or narrow zones 21 (Figure 4b) at or near the inner rims of the teeth.
Preferably too, the teeth are directed diagonally inward (i. e., the grooves are diagonal so that the teeth are undercut) and are given length and radial thickness such that they yield somewhat in an axial direction of the pipe when the bolts are tightened and lo an extent become responsive to fluid pressure Within the pipe, an increase in fluid pressure tending to tighten the joint by its tendency toward straightening out the teeth, thereby increasing the pressure between the teeth and the mating flange.
bviously the annular teeth may be upon one of the mating flanges, as in Figure 1, 4, 4a,
10, 11 and 12, or upon opposite sides of a diaphragm inserted between the flanges, as shown in Figures 2, 3, 5, 6, 7, 8 and 9a.
In Figure 2 the'flanges 11 are secured to the pipe sections 12, 13 by threads or welding and are of any standard plain-face type. In Figure 3 the flanges 112 are integral with the pipe and flanges 113 are loose or are welded to them. The diaphragm 22 is shown inserted between. It seals with each plain flange in the same manner as if the annular edges or surfaces of contact were upon a pipe flange as in Figure 1 and affords the same oppor tunity for variation of the sealing surfaces, or for axial springing of the teeth if the teeth be undercut, as in any other form.
It will be noted that the innermost tooth circle is undercut in Figures 4 and 4a but is not shown as undercut in Figure 3.
Figure 10 follows Figure 3 in that all of the teeth except the innermost are undercut though in a flange integral with the pipe.
I find some means of providing spring for the teeth to be quite desirable but am not confined in this to the undercutting feature, showing, in Figures 5 and t5 another way of securing this desirable end in order to point out that this feature is in its broader aspects not restricted to any single form.
In Figures 5 and 6 the diaphragms 22', 222 are undercut as in Figures 3, 4 and 4e and may have either edges of tooth contact as in Figure 4 or annular surfaces of tooth contact as in Figure 4a. In all of Figures 549e, the innermost tooth is undercut and each of the teeth has spring and also a tendency to tighten more with higher pressure.
In Figures 3, and 9 the diaphragms 22 and 223 are provided with duplicate surfaces and constructions on opposite sides. Each of the teeth and grooves on one side finds a duplicate of the same diameters on the other. However, this is not true in Figures 5 and 6 which secure a springing action additional to and separate from the springing action due to the undercutting of the teeth through the alternation of the teeth on opposite sides, the grooves and tooth contact portions upon one side lying radially between the grooves and tooth Contact portions upon the opposite side so as to use the lateral flexing of the diaphragms as a means of attaining the additional spring or resilience.
The lweakening of the diaphragme by grooves from opposite sides assists in this lateral flexing of the diaphragms and may be made to give even a relatively thick diaphragm great flexibility, each of the teeth being compressed axially toward the normal central plane of the diaphragm. The teeth on the same side. are compressed toward the normal central plane in the same direction but in the opposite direction from that of the teeth upon the opposite side of each ofthese diaphragme. Where the teeth are undercut there is a slight tendency under pressure to turn their edges about their anchorages to give them lateral spring in addition to the spring arising from release of compressive strains. f
The intensity of pressure of the annuli againstl thefmating flange must be determined with reference to the resilience of lthe metal and pressure which are to be applied so that there Will be no bendingl or kcompression of metal beyond the point from which ity Will fully spring back or expand.
- It Will be obvious that even in the form shown inFigure 4 Where the surfacesr at the right taper at eachftooth directly from the extreme' inner edge of the tooth, there Will ,not
be line contact alone but that With compression ofthe metal of the tooth and of the face with which it contactsr andsuch spring as may take place in radial planes there Will be a surface contact With the highest pressure at the tooth edge. In the form shown in Figure 4a, a slight plane surface for contact is deliberately shown but even this would be bes; if so out that the contacting surface becomes parallel With the mating flange after i any spring of the tooth in radial planes has taken place, and not before.
There are two reasons Why the teeth of different annuli may yto advantage not all enthe meeting flange equally when the parts are assembled prior to clamping into positon and Why they do not require the same extent of pressure or spring resilience against the mating flange when the flanges have been tightened. One of these is purely mechanical, in that the tendency of the flangesto spring makes it expedient to have contact first along the inner parts of the flanges (considered radially) even as a prerequisite to having the teeth equally pressed against theV mating flange when the joint is fully tightened. Because I prefer to have each inner annular tooth press more tightly againstthe flange than the next outer tooth I taper one or both of the flanges slightly away 'fromthe other from the inside out- Wardly or, if the gasket beused, taper the.
gasket inslead of or in addition to the' tapering of the flanges, as seen in exaggerated form in Figures 5-9a. v
The other reasonr lies in the 'successive reductions of pressure effective against the successive teeth and the fact that the outer teeth Y having less pressure upon them need ,not be so tightly clamped against the mating flange in order to hold the pressure.l
This will be ,readily understood from the fact that,rconsidering the innermost annulus, there Will beso little Vleakage or tendency to leakage past the joint formed by it With the mating :flange Vthat the pressure Within the first annular space 23 Will be very much less than that in the pipe. Correspondingly lbe- .cause of thevery slight leakage ifany past the secondannular ,tooth the pressure in the second. spaceA Will .be less than that Within y space 23' etc., with the effect that the successive annular .teeth will be subjected to pro gressively lessening fluid pressure.
I recognize that the flanges-and the gasliet-could befinade plane, Where thegreater pressure `is desiredor'needed upon the outer teeth, securing a good joint but relying chiefly on theouter annulus or annuli.
. The succession of grooves with intervening contact. annuli has been found to be` very effectiveV even With bolts Whichare relatively loose, since any. appreciable leakage involves high velocities of lflow through and past the rsuccessive belts or zones ofcontact With consequent high friction losses in pressure at these zones and very hi h shock losses of the character of Yso-called arnot-Borda impact losses infeachv groove. These losses may-be roughly measured by the square of the change in velocity in each groove. f
This is true not only in Figures 1411, Where the pressures to be held are interior, but Will be true also in such positions as Figure 12 at the valve face and about the valve seat Where the pressure is onthe outside and Where, correspondingly, the outer annular teeth must take the highest pressure and inner annular teeth receive progressively less pressure as the innermost annular tooth is approached. In all the figures in Which the annular teeth are undercut it Will be evident fha't an excessive pressureV tends to expand the' redge of the teeth into closer contact with the flanges against Which/they engage. This expansion is thus proportioned to the need and autoinatically tightens thev joint of all the annu-l .Where a'flat radial contact surface is vided as in Figure 4a Iprefer to make it very narrow, securing excellent results with as little as 1/32 of anlinch. The taper of thefsurface leading upto-the contact edge may be veryslight, good results having been obtained Wit-h as little as 1/ 100 of an inch 'on a distance of 3/16 of an inch. These dimens sions are given forthepurpose only vof show-pk ing one form of the invention from Which good results cany be obtained but with the knowledge that a great deal Lof variation is permissible and Withoutl any intention of restricting the invention by the dimensions given.
T he spring of the metal and therefore the effectiveness of the joint is affected by the character of metal used for the plain flange but particularly for the annular engaging edge or face. Excellent result-s have been obtained by use of a high carbon steel or monel metal or alloy steel withstanding high temperature.
In the form shown in Figures 5 and 6, the annular teeth are staggered on opposite sides of the gaskets 22', 222, so that compression of the gaskets between adjoining facing flanges tends to spring the metal of the gasket bodily, sinuously, first toward one axial direction and then in the opposite direction, utilizing the spring of the metal bodily to secure the spring obtained in the other form by the under-cutting or in addition to it.
The inner edges 24, 24 are both used and as shown are both undercut. Pressure on the tooth edges 25, 25, tends to bend the disc upon the edges 24 in the direction toward the observer while pressure on the edges 26, 26 tends to bend the disc away from the observer about the edges 25, 25', as a center.
Similarly pressure upon edges 27, 27', 28,
28', 29, 29 and 30 tends to liend the disc about edges 2G or 26', 27 or 27', 28 or 28 and 29 so as in each case to utilize spring of the disc as stated. Of course any anticipated bending of the disc must be allowed for in providing the taper adjacent the edge of each tooth upon the opposite side, cutting sufficiently more taper than would otherwise be required so that the desired taper may remain notwithstanding the bending of the gasket disc. It will be noted that as between Figures 5 and 6 the undercutting of the edges has been reduced in some and eliminated in others of the annular teeth in Figure 5 whereas it is present in full effect in Figure 6; also that the gasket in Figure 5 is much thinner than in Figure 6 with the result that the grooves in Figure 5 are more nearly surface grooves whereas in Figure 6 the grooves are relatively deep, sufficiently so as to weaken the metal between any one groove and the next outer groove on the opposite side so as to facilitate bodily bending of the gasket disc of Figure 6 in radial planes. As will be seen, the tapering of the flanges or/ and of the gaskets, where tapering is used, may be made sufficient for the purpose only of securing final equal compression of each of the annular teeth against its facing flange or may be increased to such an amount as to secure a much higher compression progressively of the inner teeth than of the outer tooth or teeth independently of the interior fluid pressure.
Whatever the fact as to this, the resilience of the metal itself to compression, the spring of the flanges, the spring of the teeth permitted by the under-cutting and the bodily spring of the gasket disc in such a form as that of Figures 5 and 6 as well as the expanding force of the fluid within the undercut give an extremely strong and resilient pressure between the faces of th-e annuli and the il anges and cause the annuli to maintain contact and high pressure against the flanges even where fatigue of the bolts has caused them to slack slightly in their hold.
Because of the resilience of the joint the bolts need not have the same tension as in other joints, greatly reducing and nearly eliminating fatigue lengthening of the bolts.
In Figures 7 and 8 are shown attachment lugs 31 threaded or otherwise arranged for engagement by outside means so that each disc can be supported by means of the lug to place the disc and maintain it in proper alignn'ient during the assemblage of the joint and until the disc is fitted tightly enough between the flanges to need no further steadying or support. j
In Figure 3c l have shown a gasket disc such as in Figures 5-7 used for the combined purposes of sealing between the pipe and flange and of sealing against the flange, in order to insure the tightness of the entire joint. It applicable to any form in which the pipe end is faced in proper position for engagement.
Unlike the pipe 12 which is threaded and welded into the flange in Figure l, pipe l2 which is welded and pcened into the flange in Figure 2, but both of which terminate short of the end of the flange, and the pipe 122 which is turned over to form the facing flange 112 in Figure 3, the pipe 123 in Figure 3a is threaded into the flange and Welded there but extends tothe face of the flange and is faced off in line with the plane or slightly relieved face cf the flange ,10ft so that the inner teeth 24 and 2l of the disc gasket engage with the faced ends of the pipe and seal fully againstthem.
In addition to this seal forming one of the series of sealing contacts of the gasket against the flange considered in its entirety, effective as in the other figures for this purpose, it forms a protective seal for the end of the pipe in its oint with the flange itself, protecting fully to the extent of its eflectiveness, and, so far as there may be any leakage, greatly reducing the pressure in the Zone between the pipe and the next tooth 25. This reduced pressure is much less likely to leak past the threaded and welded joint between the flange and pine than is the pressure interior to the pipe.
In Figures 1l to 17, inclusive, my invention is applied to valves for the purpose of showing the applicability of the invention to flanges generally including the face flanges of valves and the flanges of valve seats; also lilii to temporary joints such as valves for which latter purposes separate application for patent will be made.
The valves 32, 32 are provided with face flanges 33, 34, 83, 34 having annular teeth and intervening grooves corresponding to those shown in Figures 4 and 4a.- On the other hand flanges 35 are plane or slightly tapered for the purpose already indicated. These flanges are all adapted to engage with other flanges as in the structures of Figure 1. However, th-e flanges 36 upon the valve seat 37 in Figure 13 differ in that the pressure is applied in Figure 11 upon the opposite side of the seat from that to which it is applied in Figure 12 resulting in a difference in direction in the slope of the teeth in the two figures. The teeth and grooves in Figure 11 slope toward the engaging surface and inwardly as in Figure 1, whereas those in Figure 12 slope toward the engaging face and outwardly-because the steam pressure is applied to the outside of the seat.
Each of these valve seats is provided with interior engaging projections for Spanner wrench use in placingthe seat and is threaded at 38 to engage the threads of valve web'or flange 39. By means of Vthese threads the annular teeth 16, 16', 162, 163 (Figures 141-17) are forced firmly against the surface l0 of the flange making possible the same character of engagement with the same advantages of tapering one or both surfaces to make tighter engagement along the inner contacts in Figure l1 or the outer contacts in Figure 12 as in the other constructions.
The valves 41, 41 in these two figures 12 and 13 are also provided with annular teeth which may be of any of the types indicated, which teeth engage the faces orl seats 42 to close the valves. As in the case of the seal for the valve seats in the two Figures 11 land 12 the teeth and grooves are reversed in their slopey in Figure 12 as compared with the slopes in Figure 11, because of the fact that the pressure is from the outside in Figure 12 instead of from the inside as in Figure 11 and in the other figures.
I have shown the valve operating means conventionally by stems 43 operated by any mechanism not shown. y
The application to the gate valve is not in,- tended to restrict the utility to this form of valve nor, indeed, to valves as this invention has utility in the seals between valves and their seatsand between the seats and their supporting structure in many types of valve as well as in other places in which it is desired to seal between a flange and its support.
Cutting the grooves within a pipe flange so as to utilize one of the pipe flanges to carry the annular contact teeth reduces the leakage surface to a single plane or approximate plane between two flanges, offering an advantage from this stndpoint which is not found where instead of makin gthe entire flange or pipe of such' material. The machining is greatly'liac'ilitated and -the disc only need be supplied'.
It wil-libe evident that the progressivepres, eures :of different spaced annuliy against facing flanges may be of advantagein all ofthe formsV villustrated byl me whether' between facing flan ges orbetween facing plain flanges and an-l intervening gasket vor in a flange seat or rim such vas the valve seat shown or in the engagement between the valve and its seat;` c
but that my invention `is of great value valso where Athe pressures are .equal or the faces within planes. A
It will be evident moreover, that thesoll called plain faces or'flangesjneed not be plane even where dlierential pressures arefsought or relative tapers` :are desired,
provided the cooperating member vis correspondzingly changed 'in shape'to cooperate with it; andthat the progressive differences in vpressures of vthe annuli against the flanges are 4aclivantageous even when there are only three such annuli as in the illustration?Y though there is no such restriction in fact of the valve seat contacts and the valve contacts lof Figures 11 and 12. Y e
In thin gasket yformV I have 4secured ex-` cellent results without undereutting; also by sloping the teeth in radial planes directly from the extreme edge of the toothv or from va point just .back of the edge to the bottom of the groove giving a very much steeper slope to the axially directed outer face of the toot'lizthan inthe example cited.v I have found vanadium steel, nickel steel and chrome-'nickel steel amon'gotheralloy steels give af resilience `and stand up under the temperatures corresponding to high press.
sures and superbe-ats infa 'way' well. suited sion and yet will permit some slacking and still hold. `In such a location as seen in Figure 18, for example, they will permit slight 'rocking of the flanges due to eXpansion and contraction of the straight pipe sections without leakage and, in general, in all locations will stand' up under longitudinal, diagonal and lateral strains to a remarkable extent.
By maintaining a balance of compression such that the oint Will stand additional compression on one Hange side with or Without release of part of the compression across the flange at the opposite side without eX- oeeding the compressive limit upon the part additionally compressed nor losing compres- *10 sion too much to maintain tightness of joint Where the compression is somewhat slacked, I secure substantially fool-proof conditions as against lateral strains to the system and rocking or diagonal strain upon the joint, at the same time protecting against such slacking as takes place by reason of fatigue of the bolts. In reliability and permanence my joints are quite comparable with welded joints at the same time that replacements and repairs involve cost, time and trouble insignificant as compared with these items for Welded joints.
Undercutting as herein used is intended to refer to cutting beneath the surface so l gg, as to leave an axiallj7 overhanging ledge which will tend to bend in a radial direction l in response to axial pressure.
Attention is directed to the fact that the surface undercut need not mali@ contact along :o a line only but may make contact along a narrow annulus instead of with greatest pressure alongr a line and reducing pressure over the remainder of an annulus of ultimate contact.
It will be obvious that in view of my disclosure herein a large part or all of the bene fit of my invention may be secured by those skilled in the art by constructions and methods which are not copied from. mine but which contain the same inventive concept. It is my purpose, therefore, to include herein all such modilications and changes as come within the reasonable spirit and scope of my claims. Having thus described my invention, what I claim as new and desire to secure by Letters Patent is The method of giving resilience to a solid l metallic gasket which consists in providing 59 narrow spaced annular surfaces engaging with facing flanges on opposite sides of it, in placing the annular contacts at dii'erent distances from the axis on one side of the gasket as compared with those on the opposite side thereof to spring the gasket and undercutting the surfaces.
WiLLIAM F. OBERHUBER.
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US2484620 *||May 28, 1946||Oct 11, 1949||Wingfoot Corp||Flexible protective cushion for tire chafer area|
|US3017699 *||May 1, 1958||Jan 23, 1962||Mondie Forge Company||Method of making bolting collars|
|US3083989 *||Apr 30, 1957||Apr 2, 1963||Resistoflex Corp||Reusable fitting with metallic sealing ring|
|US3403717 *||Feb 14, 1966||Oct 1, 1968||Jerome H. Lemelson||Sealing and bonding device|
|US4171142 *||Sep 12, 1977||Oct 16, 1979||Team, Inc.||Leak repair clamp|
|US5282652 *||Oct 22, 1991||Feb 1, 1994||Werner Pipe Service, Inc.||Lined pipe joint and seal|
|US5470114 *||Nov 14, 1994||Nov 28, 1995||General Electric Company||Coupling assembly|
|US5560656 *||Sep 2, 1994||Oct 1, 1996||Ck Metals, Ltd.||Pipe connecting structure|
|US5975844 *||Mar 30, 1998||Nov 2, 1999||Siemens Aktiengesellschaft||Sealing element for sealing a gap and gas turbine plant|
|US6883807 *||Sep 13, 2002||Apr 26, 2005||Seimens Westinghouse Power Corporation||Multidirectional turbine shim seal|
|US7562880||Feb 9, 2004||Jul 21, 2009||Siemens Energy, Inc.||Seal usable between thermally movable components|
|US20040051254 *||Sep 13, 2002||Mar 18, 2004||Siemens Westinghouse Power Corporation||Multidirectional turbine shim seal|
|US20050173871 *||Feb 9, 2004||Aug 11, 2005||Siemens Westinghouse Power Corporation||Seal usable between thermally movable components|
|US20060237463 *||Apr 21, 2006||Oct 26, 2006||Tony Riviezzo||Component seal for plastic tanks|
|DE973855C *||Oct 24, 1953||Jun 30, 1960||Klein||Dichtgeschweisste Rohrflanschverbindung|
|DE3418439A1 *||May 18, 1984||Nov 21, 1985||Reinz Dichtung Gmbh||Ribbed tapered sealing ring for flange joints|
|U.S. Classification||29/558, 285/354, 285/368, 82/1.11, 29/890.14, 285/110|
|International Classification||F16L17/00, F16K1/32, F16L17/06, F16K1/34|
|Cooperative Classification||F16K1/34, F16L17/063|
|European Classification||F16L17/06B, F16K1/34|