WO1989012190A1

WO1989012190A1 - Radial pressure seal

Info

Publication number: WO1989012190A1
Application number: PCT/EP1988/000484
Authority: WO
Inventors: Erhard Weber
Original assignee: Erhard Weber
Priority date: 1988-05-31
Filing date: 1988-05-31
Publication date: 1989-12-14

Abstract

Said radial pressure seal consists of a sealing unit (A), having a dynamically balanced radial sealing lip extending outwardly or inwardly (1, 1'), and of a second sealing unit (B), having a counter-surface which can be cylindrical (4), cone-envelope shaped (2) or curved inwardly (3) or outwardly (3'). Tightness is achieved by radially pressing together the sealing lip (1, 1') and counter-surface (2, 3, 3', 4), optionally with the help of an additional device or process. Said radial pressure seal is particularly advantageous in that the radially operating pressure force pr generates a narrow axially-stationary sealing surface in the shape of a circular line between the radial sealing lip (1, 1') and the counter-surface (2, 3, 3', 4). Minimal pressure is therefore required to achieve the sealing effect; the seal is easy to release and to reuse and can be replaced a large number of times. Said radial pressure seal is particularly suited for metal-metal embodiments where ultrahigh vacuum (UHV) and pressure are applied to flanges and valves, even in the case of nominal widths (NW) greater than 150 mm, for sealing and closing pipes and containers, and combined with known small-flange and clamped-flange systems, which can thereby be subjected to UHV.

Description

RADIAL PRESS SEAL

DESCRIPTION

The invention relates to a press seal with a radial sealing lip, preferably in a metal-metal design, which can be used in a variety of ways for ultra-high vacuum (UHV) up to high pressure, which manages with a low, radially acting pressing pressure to achieve tightness and with a suitable choice of sealing lip materials and counter surface allows frequent reuse and remains tightly sealed with large temperature changes.

Vacuum and pressure seals have hitherto been achieved by welding, soldering or by axial or combined axial-radial pressing with or without the addition of a sealing ring.

In the known Conflat flanges ^R (registered trademark of the Varian company), for example, axial cutting edges, which are each formed in two opposite flanges, are axially placed in an interposed copper sealing ring with a high pressing force 0.2 to 0.5 mm deep pressed in. The flanges are very solid and the sealing ring must be replaced each time the seal is loosened. Conflat flanges are only standardized up to nominal values of NW 150 and for NW 250 only available as special designs.

By inserting thin (0 = 1 ... 1.5mm) precious metal O-rings into the matching groove, which is inserted on one side into a paired flat flange, a high axial pressing force enables a UHV seal even for nominal widths NW> 250 can be achieved.

Other known metal-metal seals use axial pressing in or pressing in of conical surface areas of different rise angles. Also known is an axial cutting ring seal, which is used for the tight connection or connection of pipes by axially pressing the separate, conical cutting ring into the guide cone of a pipe sleeve, two separate sealing surfaces being created, one between the pipe and the cutting ring and the second between the cutting ring and guide cone. In these cases, the primarily axial pressing process results in a λ ^ displacement of the sealing surfaces and mostly in a peeling or peeling of material, which often only achieves the sealing effect. Reusability or exchangeability is thereby restricted.

Pressure tightness can also be achieved by tightening conical threads, the thread length being greater than the thread diameter, usually with the addition of plugging or flowing additional sealants. However, vacuum-tight connections cannot generally be achieved with this. -z-

By axially pressing two polished spherical surfaces with different radii, high vacuum and pressure tightness can also be achieved. In this case, the machining of the surfaces of the solid spherical bodies is very complex, and the type of connection is therefore expensive. The polished surfaces are very sensitive, even against twisting against one another, and the contact pressure required for sealing is high.

The object of the invention is to achieve an inexpensive, safe high vacuum and pressure seal, preferably in a metal-metal design with low material and processing costs and low to moderate contact pressure, which ensures good detachability and reusability or a high number of change cycles.

This object is achieved with the tight connection of two hollow cylindrical pieces, pipes, flanges, containers or the like, or with closures or valves, in that a part has a sealing member A with an outwardly or inwardly directed rotationally symmetrical radial sealing lip and the other part has a sealing member B with a cylindrical, cone-shaped, concave or convexly curved counter surface, and the two sealing members are tightly connected to one another by a uniformly radial contact pressure, forming a narrow, circular-shaped sealing surface between the sealing lip and the counter surface.

The radially uniform contact pressure, possibly with reversible or irreversible cross-sectional widening or narrowing, is advantageously brought about by a suitable mechanical aid, such as an axially concentrically drawn or drawn in press cone, a press belt made of individual members acting peripherally inwards or outwards a clamping or pressing ring, an axial stop or a stop plate for cross-sectional widening or narrowing of shells or shell zones with radial sealing lips at the end, a rolling-in or radially acting pressing tool, such as a rolling-in pliers or a roller chain, or also by an express process, which causes a shrinking or shrinking by temperature change, if necessary with the aid of a separate annular hollow body, a bimetal ring or a disk.

Preferred embodiments of the invention are listed in the subclaims. The particular advantages of the invention are that

1) When installing the seal, there is a separation between the closing process, i.e. the mostly axial merging and concentric pre-adjustment of the sealing members and parts, and the sealing process due to the radial pressure; this leads to

2) for automatic self-centering with cylindrical, conical and spherical counter surfaces and

3) by the uniformly radially acting pressure to form an axially stationary, closed, narrow circular sealing surface between the radial sealing lip and the counter surface.

The radial sealing lip is formed by a surface or by the meeting of at least two surfaces, which e.g. are convex or concave curved shell or spherical zone surfaces, concentric conical surface, ring or cylinder surfaces or consist of a combination of these surfaces. The radial sealing lip can advantageously be either more sharp-edged than a radial cutting edge or more spherical, optionally rounded off with a radius r, depending on

Material, ductility and surface quality, as well as the wall thickness and elasticity of the sealing components connected to the sealing lip and the counter surface.

Thus, even with low to moderate pressure, based on the radius of the radial sealing lip, there is reliable high vacuum and pressure tightness even with the same material, e.g. Stainless steel, from the cutting edge and counter surface. This is achieved by a stationary extrusion process of the material of the sealing lip and / or the material of the counter surface, as a result of which the microstructures of the two surfaces adapt optimally on the narrow circular sealing surface.

When the contact pressure increases or when media pressure is applied, the sealing lip becomes firmer and a hollow cylinder edge and surface lying behind it are also pressed onto or into the counter surface, as a result of which a second high-pressure seal is created. This results in an increase in the compressive strength, which is further supported by an increasing wall thickness of the hollow cylinder.

When using the same material or material with approximately the same thermal expansion coefficient for the sealing lip and counter surface, the tightness is given even with a large temperature change; For example, when using stainless steel (material no. 1.4571), high vacuum (He) tightness was retained for the exemplary embodiments which are shown in FIG. 2 to FIG. 4, even after repeated cooling to T = −193 ° C. ( liquid nitrogen temperature) and repeated heating to T = 450 ° C. The radial press seal is therefore also ideally suited for ultra-high vacuum use. The invention is to be explained in more detail below on the basis of 19 exemplary embodiments which are illustrated in 17 drawings, from which further features and advantages of the invention can be gathered. Show in the accompanying drawings

Fig. 1 (a) a sealing member A with a radial sealing lip and a sealing member B with a rotationally symmetrical cylindrical (-) or (—- "*) conical counter surface, (b) a sealing member A with a spherical radial sealing lip and a sealing member B with cylindrical (-), concave (-) or convex (* "- *") curved counter surface

2 shows a connection piece for containers with a combined pipe connection sleeve, each with an integrated radial sealing lip

3 shows a connecting piece for containers with a radial sealing lip integrated in the bore and a combined pipe connection sleeve with an enclosed radial double sealing lip ring

Fig. 4. a connection seal for two pipes, one with an integrated radial sealing lip and one with a conical counter surface

5 (a) a pipe joint seal with a radial sealing lip,

(b) after narrowing of the cross-section by curling,

(c) a hollow cylinder connection seal with radial sealing lips and cross-sectional widening by means of an internal press cone

Fig. 6 shows an ultra high vacuum valve with a radial sealing valve seat

Fig. 7 flange connection seals with radial sealing lips and

(a) a cylindrical outer sealing ring,

(B) a V-shaped outer sealing ring made of spherical shell zones with a radially acting press belt

8 (a) a shell-shaped sealing element A with a radial sealing lip and a sealing element B with an axial stop and a cylindrical (-) or conical (-) counter surface,

(b) and (c) flange connection seals with axial stops and intermediate sealing rings with radial sealing lips formed on the ends, which are V-shaped in cross section (b) or obliquely rod-shaped and X-shaped (c)

9 shows a valve closure, consisting of a cup-shaped plate with a radial sealing lip,

(a) with axial stop and cylindrical seat,

(b) with separate stop plate and conical seat 10 shows a UHV butterfly valve, consisting of a disk-shaped plate with a radial sealing lip and a thin-walled spherical shell zone as a valve seat.

FIG. 1 (a) shows schematically and as a section a sealing member A with a radial sealing lip 1, which is designed as a cutting edge, and a hollow body 5 'as a sealing member B with a cylindrical 4 or conical 2 counter surface.

FIG. 1 (b) shows a sealing element A with a radial sealing lip 1 ′, which is rounded off with a radius r, and a hollow body 5 ′ as sealing element B with a concave 3 or convex 3 ′ counter surface. The sealing members A and B are sealed by pressing the sealing lips 1, 1 'against the counter surfaces 2, 3, 3', 4 or vice versa with the aid of a pressure p _r or p _r which acts uniformly on the periphery, optionally under Cross-sectional narrowing or widening of the sealing elements.

FIG. 2 shows a connecting piece 9 which fits with a short hollow cylinder piece 5 with a structurally integrated radial outer sealing lip 1 as sealing member A into a bore 10 in a container wall 8 as sealing member B of a container to be evacuated or to be pressurized with high pressure ¬ is set. By a press cone piece 12, e.g. with an internal thread that is pressed into the hollow cylindrical piece 5 in the axial direction, the sealing lip 1 is axially stationary, concentrically radially pressed onto or into the bore wall 4. The press cone piece 12 can in principle also be removed again after the assembly or after the pressing operation of the sealing lip 1 designed as a cutting edge into the surface 4 of the bore 10.

The connecting piece 9 in Figure 2 is combined with a pipe connection sleeve, in the hollow cylinder piece 5 'with external thread and structurally integrated radial inner sealing lip l' as sealing member A ', a pipe 7 is inserted as sealing member B'. The radial sealing lip 1 'is pressed on or pressed in by screwing on a union nut 6 with an integrally formed external press cone.

Figure 3 shows a connecting piece 58, which is inserted into a bore 20 of a container wall 18 with an integrated radial sealing lip 11 as the sealing member A, and the integrally formed hollow cylinder piece 15 as the sealing member B by means of a press cone piece 22 on the sealing lip 11 for a tight and firm connection ¬ dung is pressed.

The radial sealing lips (1, 11) in Figures 2 and 3 are advantageously started at that connecting part which consists of the harder material. The sharp-edged radial sealing lip in the bore can be formed from outside the container, for example with the help of a step drill and a backward deburring tool.

The connecting pieces 9 and 58 in Figure 2 and 3 can be used identically in the bore of a pipe end or in bores in a hollow cylinder wall vacuum and pressure. The machining of the bore, the insertion of the connecting piece and the sealing process can all advantageously be carried out from outside the container or pipe, so that subsequent installation in existing equipment is possible.

For large mechanical loads, the hollow cylinder pieces 5 and 15 in Figure 2 and 3 and / or the bores 10 and 20 above the radial cutting edges 1 and 11 can be provided with a corrugation or thread, which during the closing process, before and regardless of the sealing process by pulling the press cone pieces 12 and 22, a mechanically firm connection.

Two further advantages of the radial pressure seal of connecting pieces are that they are inserted into simple bores of relatively thin-walled containers or the like, e.g. in comparison with conical thread seals, and that two parts made of very different, e.g. non-weldable materials, can be tightly and mechanically firmly connected.

After cutting the sealing lip, which is designed as a radial cutting edge, into the counter surface by pulling the press cone more axially, the connection remains tight and mechanically strong even after it has been removed.

In FIG. 3, a pipe connection sleeve 58 is shown in the upper half similar to that in FIG. 2, but here with the enclosed separate sealing ring 52 with two opposite radial cutting edge sealing levers 51 and 51 '. The sealing is carried out by radially pressing in the radial double cutting edge ring 52 both into the outer surface of the inserted pipe 57 and into the hollow cylindrical piece 55 of the pipe sleeve 58 by means of a union nut 56 with an integrally formed press cone, two closed, narrow, circular-knee-shaped sealing surfaces form.

Tightness and, at the same time, mechanically firm connection is achieved in all cases with moderate pressure, if the radial sealing lip and the counter surface are finely turned, the bore is drilled out with hard metal drills and, for diameters> 15 mm, eg with a reamer, reamed or finely turned out is (according to DIN 3141: arbitrated). Post-processing of tube walls 4 'is generally not necessary for commercially available grades.

FIG. 4 shows a high-density connection between two pipes 28 and 29. At the end of the tube 25 is a hollow cylindrical piece 25 with an internal radial sealing lip, which is pressed concentrically radially by means of an outer press cone flange 32 onto the end-side conical concave or convex taper 27 of the second hollow cylinder piece 28. The radial press seal is made by axially contracting the movable flange 32 with an external press cone and the immovable flange 33 fastened to the tube 29 with the aid of a (split) clamp 34 which is pulled onto the bevelled outer webs of the flanges 32 and 33 and moves them towards one another.

If necessary, a piece of pipe with an end widening onto a second with an outer radial sealing lip formed on the end can be pressed on in an analogous manner, as shown above and in FIG. 4, and tightly connected to it.

For simple, concentric insertion and loosening, a suitable guide 26 is advantageously screwed onto both pieces of pipe to be connected.

FIG. 5 (a) shows a connection between two pipe pieces 38 and 39 inserted one into the other, one (39) of which has at least one sealing lip 31 designed as a radial cutting edge and the other (38) of which is smooth. By subsequently narrowing the cross-section of the outer tube 39, e.g. by rolling in the area of the radial cutting edge 31 with a plurality of symmetrically radially pressing rollers of a curling tongs, see FIG. 5 (b), the two tubes are tightly and mechanically firmly connected to one another, the narrowing of the cross section being drawn oversized for clarity.

Figure 5 (c) shows a connection between two hollow cylinders or tube pieces 68 and 69 which, as shown in Figure 5 (a) and above, are constructed and by cross-sectional widening 67, e.g. are tightly and mechanically firmly connected to one another by means of a subsequently pressed inner press cone piece 65.

In the case of the last two sealing connections mentioned, at least one of the tubes advantageously consists of a material which can be easily cold-deformed, such as e.g. Copper.

In the case of copper, in particular, the radial cutting edges (partially or entirely) can be formed by rolling in with simultaneous surface hardening with the aid of a rotationally symmetrical tool which engages obliquely inwards in the corresponding cylinder surfaces. The cross-sectional narrowing or widening can be carried out with simple tools on site at an apparatus or construction site, even during repairs. 2190.

-S- are performed.

FIG. 6 shows a corner valve in an ultra-high vacuum design, the valve seat of which is a short hollow cylinder piece 45 with an integrated internal radial sealing lip 41 which is a uniform component of the valve housing 49. In the closed state, the frustoconical valve disc 44, e.g. by means of a helical compression spring 46, applied to the radial cutting edge 41, which in turn is pressed radially concentrically radially against the conical surface of the valve disk 44 by axially pressing on an outer press cone 42. The axial movement for closing and opening the valve is made possible by a pressure piece 43 integrated with the press cone 42 and the threaded pin 47 with pressure pin used. A metallic corrugated bellows 48, which is welded to the pressure piece 43 and the valve housing 49, ensures the ultra-high vacuum tightness to the outside.

In the all-stainless steel version, very high closing and opening cycles of the valve and heating when closed are possible without impairing the sealing function.

In all of the seal connections described, depending on the material and size of the parts to be connected, it may be advantageous to replace the radial cutting edge, which is structurally integrated on one part, by a separately provided multiple radial sealing ring. Due to the free choice of a suitable ring material, preferably harder than the material of the parts to be sealed, the advantages can be greater than the disadvantage of the at least double sealing surface.

7 (a) and (b) show two flanges 79, 79 'with radial sealing lips 71, 71' and 1, l 'at a distance d and d' against which a thin-walled intermediate ring 72, 72 ' with width b is pressed uniformly radially from the outside with the help of a press belt 70, 77 from individual, interconnected links or a tension ring.

Particularly advantageous is the composition of the V-shaped sealing ring 72 'from two spherical zone shells 76, 76' placed against one another, which makes the sealing within the spherical zone region 73, 73 'largely independent of tilting of the two flange axes relative to one another. Radial ellipticities and inequalities of the outer circumference of the sealing lips can be compensated for by elastic yielding of the thin-walled hollow cylinder pieces 75, 75 'when the sealing rings 72, 72' are pressed radially. The two sealing lips 71, 71 'can also be placed axially against one another (distance d = 0), which results in two circular, helical sealing surfaces lying very close together when the ring 72 is pressed radially and the sealing lips 71, 71' have sharp edges. By axially pressing together 'n3' the radial sealing lips 71, 71 'at a distance d = 0, or by means of a separate or a stop ring 66 which is structurally integrated on the intermediate ring 72, the axially applied pressing force is transformed into a radial contact pressure. With largely elastic deformability of the radial sealing lips 71, 71 ', there is a reversible widening of the contact circle with cross-sectional area Q of the sealing lips 71, 71' on the intermediate ring 72 and thus a radial, axially largely stationary attachment and optionally Pressing the sealing lips into the intermediate ring 72, which in this case replaces the radial pressing of the intermediate ring 72, see below and seals in FIGS. 8 and 9.

FIG. 8 (a) shows schematically and as a section a bowl-shaped 109 sealing element A with a radial sealing lip 101 at the end, which is rounded off with a radius r. The sealing member A is expanded in the radius RQ of its largest cross-sectional area by axial pressure in the area of the sealing lip 101 with pressure p _a against an axial stop 106 which is connected to the sealing member B or can be separated from it the radial sealing lip 101 is pressed radially and tightly against the cylindrical 4 or cone-shaped 2 counter surface of the sealing member B.

A puncture 103 (93 in FIG. 9 (a)) into the sealing member B between the axial stop 106 (96) and the counter surface 4, 2 extends the thin-walled ring (98), web 108 and enables easier adaptation of the counter surface 4 , 2 to the radial sealing boss 101 (1 ') under the radial contact pressure p _r to compensate for any radial ellipticity, axial unevenness of the shell edge 107 and / or the stop 106 (96) and any tilting of the axes of the two sealing members against each other . An elastic shearing and / or twisting of the sealing members A (92, 102, 104 ', 94, 94' in FIGS. 8 (b, c) and 9 (a, b)) with radial sealing lips can serve the same purpose or contribute to this.

8 (b) and (c) show flanges which have axial stops 96, 96 ', 106, 106', between which sealing rings 92, 102, 104 'with radial dial sealing lips 91, 91', 101 to 101 '"are pressed together. In cross section, the sealing rings are open outwards or inwards in a V-shape (92), obliquely rod-shaped (104') or X-shaped (102). The axial pressure on the stops 96, 96 ' , 106, 106 'causes a reduction or enlargement of the cross-sectional area Q, Q' of the sealing lips and thus a radial, tight contact with the cylindrical counter surfaces 4, 4 'with the formation of axially largely stationary, narrow circular sealing surfaces.

Slightly convex or concave curved or conically inclined counter surfaces against the flange axes can be advantageous if the sealing lips are appropriately rounded. With the flange connection seals shown in FIGS. 4, 7 and 8 (b) and (c), small flanges up to nominal size NW 50 with the external dimensions according to DIN 28403 can be used as paired or unpaired flanges suitable for UHV. By arranging the radial sealing lips and counter surfaces on the flange parts accordingly, it is possible to achieve high vacuum tightness with the known O-rings made of elastomers, for example for test purposes.

With nominal widths NW> 50 mm, the corresponding flange components are advantageously pulled together by means of a divided clamping device with a plurality of screw connections distributed tangentially evenly around the circumference, or by evenly pulling together two flanges, e.g. with the outer dimensions of the clamp flanges according to DIN 28404 with the help of separate claws.

9 (a) and (b) show valve, pipe or bore closures, the closure plates of which consist of rotationally symmetrical shells 94, 94 'with sealing lugs 1' formed on the edge, which are fitted into a cylindrical 4 or conical 2 counter surface the locking seat 98, 98 'are used. The cross-sectional areas Q, Q 'of the sealing lugs 1, 1' are axially pressed against the shell 94 against an axial stop 96 connected or separate with the seat 98 and the shell 94 'against a separate, axially against the shell bottom 100'. moved plate 90 elastically expanded so that the sealing lugs 1 'are pressed radially and tightly against the counter surfaces 4, 2. A reduction in the shell wall thicknesses on the bottoms 100, 100 'facilitates the elastic expansion. A puncture 93 behind the axial stop 96 advantageously extends the thin wall thickness of the locking seat 98 and thus enables an improved elastic adaptation of the counter surface 4 to the radial sealing lip 1 '. Radial holes 93 ′ prevent pockets that cannot be evacuated between sealing lip 1, counter surface 4 and stop 96.

In order to enable easier machining, possibly polishing of the counter surfaces 4, 2, 3, 3 ', the axial stops 96, 106, 106' can be used as separate, e.g. inserted rings are formed.

In the following, the decisive forces and pressures and the resulting conclusions for the seals in FIGS. 7 (a), 8 (a-) and 9 (a, b) are given, as well as a comparison of the seal with and without an axial stop employed. For this purpose, the assembly of the sealing members is divided into a closing process I and a sealing process II.

The primary axially applied contact pressure F _{c is} shown schematically in FIG. 8 (a), with F _Q = p _a • TΓ (R -Γ) ² mp _a • πR _ß for RQ • r. The forces F ' _Q , Fj. and F ^, which on a conical mating surface 2 without axial

Act stop, are shown in dashed lines (-) in Figure 8 (a). The shell zone 104 has an angle of rise φ and the conical surface 2 is also inclined by the angle ψ '= ψ against the axis C. Carrying out the following considerations is also readily possible for ψ 'ψ or spherical counter surfaces and leads to the same results in principle with somewhat more complex equations.

I '. Closing process without an axial stop

The primary axial force T? ' ₀ can be divided vectorially into a component F _j _ = Fj acting perpendicular to the counter surface 2. sin φ, which acts solely as a sealing force, and into a downhill component Ff. = Fj, cos φ>F'x for <, 0 <45 ^O , which acts tangentially on the sealing lip 101 and causes a friction or sliding movement - depending on the surface condition - along the contact surface between lip 101 and the counter surface.

During the closing process there are radial elasticities of the lip and the face

As a result, very small manufacturing, in particular closing movement tolerances, very fine machining (polishing) of the surfaces involved and the application of a sliding layer to at least one of the surfaces involved are required.

I. Closing process with an axial stop

The downward force component is zero here and, by means of an advantageously sliding, axial movement of the rounded upper edge 107 of the sealing member A at the stop 106, the primary axial force F _{0 is converted} into a radial contact force F ₉ 0 = F ₀ sin φ cos ψ with F90 «F ₀ sin φ = ^~ Fj_ for y></ 2, see Figure 8 (a).

This leads to an axially largely stationary (see II) adjustment and insertion of the radial sealing step 101 and counter surface 2. For the cylinder counter surface 4, a uniform radial contact pressure and sealing pressure p _a only builds up after complete application. -42-

II. Sealing process with an axial stop

For this purpose, the axial pressure work W _a = p _a - Q _a - ^ H _a (1) is considered, the radial sealing work W _r = _Pr - Q _r . -_iR _Q (2) is to be implemented, in the case of the cylindrical counter surface 4, with Q _a PÜ 7ΓR _Q , the largest cross-sectional area of the radial sealing lip 101 AΗ. _Ά = 1 cos ψ • Aψ, the axial displacement stroke in the event of an angle change - Aψ the rise angle ψ of shell zone 104 with length 1, and Q _r = 27ΓRQ • h, the circular-knee-shaped sealing surface with radius RQ and width h between radial sealing lip 101 and counter surface 4, and

_ RQ = AΗ. _& • tan ψ, the radial expansion stroke of the radius RQ by elastic deformation of the shell zone 104, the counter surface ring land 108 and / or by elastic / plastic deformation of the radial sealing lip 101 and / or counter surface 4.

With a relatively thin-walled design of the shell zone 104 in comparison to its length 1, the work ΔWψ = kφ ~ F ₀ Λ-Aψ for the elastic reduction Aψ of the angle ψ, with kφ = const., A constant that depends on the geometry and the . Material of the shell 109 depends, compared to the sealing work AW _{T are} neglected. Then it applies

___W »« __ W _r , (3) and for the increased radial contact pressure p _r results

With a nominal width of NW 100 mm, RQ ÄS 50 mm for angle v? = 10 ° to 25 ° and sealing surface widths h = 0.1 to 0.5 min the ratio of the applied axial pressure p _a to the resulting radial sealing pressure p _r

So p _{r increased} to very high values.

With p _a RS F _O / TΓRQ, equation (4) turns p _r «F _O / 271-RQII tan ψ. (4 ')

If the nominal size NW is increased, ie of RQ, p _r = const. the axial pressing force F _Q can only be increased proportionally RQ. Through the axial pressing movement with stroke AΕ. _& there is a flexing movement of the radial sealing lip 101 rounded off with radius r on the counter surface 4

Rotation stroke r _Λ -. rcosω ___

ΔE _T «- • ΔE _a = ^γ A o. (5)

1 RQ tany? ^ '

For ψ = 15 °, RQ = 50mm and ARQ = r / 2 = 0.25 mm, the walk stroke is only AR _r «10 μm.

II '. Sealing process without an axial stop

Due to the downward force Ff, = Fj _> • cos ψ, the flexing movement with stroke AΗ _{T is} superimposed by an additional sliding-friction movement with stroke ΔΗ'ή if the radial expansion ZIRQ is partly due to elastic deformation of shell zone 104 or Ring web 108 takes place. ARl ^ = ΔRQ / _Q • sin φ with kg ≥ 1 of a sliding friction constant whose value is close to 1 in the case of low sliding friction resistance, as is advantageously chosen for the inevitable flexing movement by applying a sliding layer. The ratio AΗ.γ / Δ! Αm tu RQ / _ß • r will then take values significantly greater than 1.

From these statements, in particular equations (4) and (5), the following advantageous choice a results for the seals in FIGS. 7 (a), 8 and 9. for the geometry

- Rise angle ψ and angle of inclination ψ 'small (cylinder surface)!

- ratio r / 1 small, and b. for the materials

- Elastic material for both sealing elements A, B

- Little ductile or equally hard surface materials for the radial sealing lip 101 and the counter surface 4, 2

- thin sliding layer (e.g. Ag) on the sealing surface and / or counter surface.

The seals with an axial stop have the following features and advantages in comparison to a seal without a stop

1. separation of the sealing and sealing process,

2. No translation movement besides the minimized rotation-walk movement on the sealing surface 4, 2, 3, 3 ', this is what happens

3. for a radial compensation of tilting, ellipticity and non-concentric merging during the welding process, ie to lower demands on the manufacturing and welding movement tolerances and on the surface qualities, 4. to build up a uniform, purely radial sealing pressure p _r during the sealing process,

5. an elastic, radially acting preload and sealing tension of both sealing members A, B by the axial contact pressure p _a against the stop 106, 106 ', 96, 96', for example to compensate for expansion processes when the temperature changes,

6. the possibility of choosing the radius RQ of the radial sealing lip 101 to be smaller than the radius of the counter surface 4, 2 at the level of the subsequent sealing surface, and thus to bring the sealing members A and B together up to the stop 106 without tangential contact,

7. the possibility of using cylindrical counter surfaces 4, 4 'for which the tilting problem becomes minimal,

8. to protect the sealing surface 4, 4 ', 2, 3, 3' provided by ring webs, e.g. 108.

A large part of these features and advantages also apply to the radial press seals which are shown in FIGS. 2 to 6 and 7 (b) and described in the text above, in particular items 1, 3, 4, 6 and 7 .

FIG. 10 shows a UHV butterfly valve with a thin-walled concave spherical shell zone 83 with radius R as the valve seat, which is integrally formed in a hollow cylinder piece 82. The valve disc consists of a disc 85 which can be tilted by a diameter D 2 R with an external radial sealing ring 81. The disc 85 is e.g. stored on tips and connected to hollow cylinder piece 82 by an arm 88. With the help of a press belt 87, which is drawn up from the outside and uniformly peripherally and radially inwards and presses onto the spherical shell zone, it is elastically deformed and pressed tightly against the radial sealing ring 81 of the plate 85.

The TeUer is exactly fixed by spacers 86 or 86 'in the locking stiffener transversely or in the open position lengthwise in the hollow cylinder piece 82 and e.g. easily held by permanent magnets 84.

The change between open and closed positions can e.g. with the help of a half-ring-shaped horseshoe magnet 89 and an induction coil 80 without mechanical feedthroughs through the hollow cylinder 82. With a corresponding shape of the likewise thin-walled side parts 83 'of the spherical shell zone 83, a spring cover effect for resiliently springing back the valve seat into the open width with a radius R can be used. The valve disk can be used or removed in the open control by a small diametrical widening of the spherical shell zone 83 and the side parts 83 'by suitable application of pressure from the outside.

The radial sealing boss 81 is advantageously spherical and made of the same or somewhat softer material than the valve seat 83. When using --IS- stainless steel for both parts, a thin, more ductile layer, for example made of copper with a few μm gold or silver protective layer, can be galvanically applied to the sealing lip and / or the spherical shell zone 83, as a result of which the contact pressure required for tightness is further reduced .

The valve can be baked out in closed and tight condition even with one-sided loading with air pressure up to 450 ° C. A constriction 85 'in the valve plate improves the expansion behavior when the temperature changes rapidly. The particular advantages of this UHV butterfly valve are that

1. it is a two-way valve with a short overall width,

2. the cutting process is separated from the sealing process,

3. the low radial contact pressure required for tightness is applied by an external press belt that does not reach into the interior,

4. whose pressing pressure is exerted radially, precisely and completely on the circumference of the sealing surface and

5. even after a high possible number of sealing and opening cycles only needs to be increased slightly, and that

6. no mechanical bushings or bellows are required,

7. no canting problems occur due to the ball zone counter surface, and

8. an axially stationary, narrow circular sealing surface forms,

9. Which results in the possibility of producing valves with nominal widths NW that are heatable in the tight state and exposed to air pressure on one side, and that are significantly larger than 250 mm

10. can be opened and closed easily and also electrically or pneumatically with a remote control.

The radial press seal can be used in many different ways and with a large number of materials for the parts that are to be sealed against overpressure or underpressure of gases or liquid media. Corrosion can be effectively prevented by using the same, resistant material for the parts with an integrated radial seal and for the counter surface.

The following additional measures can supplement and, if necessary, improve the effect of the radial press seal:

- Hardening or surface hardening of the radial sealing blocks using methods known from the prior art.

- Partial or complete molding of the radial sealing lip by a rolling process with surface hardening.

- Application of ductile materials to the radial sealing bosses and / or to the counter surfaces.

- Surface of the sealing surface and counter surface. Heating of the parts to be sealed to facilitate the pressing process on the narrow, annular sealing surface between the sealing ring and the counter surface.

These additional measures can be used to achieve tightness with an even lower contact pressure of the radial sealing lip and counter surface, more frequent possibility of loosening, changing and restoring the seal.

Claims

RADIAL PRESS SEAL CLAIMS

1. Radial press seal for the production in particular ultra-high vacuum and / or high pressure-tight connections or closures, characterized in that a sealing member A has an outwardly or inwardly directed rotationally symmetrical radial sealing lip (1, l '), a second sealing member B. has a counter-cylindrical (4), conical (2), concave (3) or convex (3 ') curved surface, and the two sealing members A and B by radially acting pressure, forming a narrow, circular sealing surface between the sealing lip ( 1, 1 ') and counter surface (2, 3, 3', 4) are tightly connected.

2. Seal according to claim 1, characterized in that the sealing member A or B consists of an advantageously thin-walled, rotationally symmetrical hollow body (5, 5 ', 5 "), which is narrowed or widened by cross-section with the help of a uniformly peripheral radially inward or . externally pressing process and / or auxiliary means is pressed in a sealing manner onto the counter surface (2, 3, 3 ', 4) or radial sealing lip (1, 1') of the respective other sealing element which is concentrically opposite.

3. Seal according to claim 2, characterized in that the auxiliary ent ent either a) consists of an axially concentric or drawn-in press cone (12, 22, 32, 42) or b) of an axial stop (66, 96, 96th ', 106, 106') or a stop plate (90) for cross-sectional widening or narrowing of shells (94, 94 ') or shell zones (104, 104', 114, 114 ') with radial sealing plugs (l', 101 to 101 '", 91, 91') or c) from a press belt (70, 77, 87), clamping or press ring acting peripherally radially inwards or outwards, or d) that the contact pressure by temperature change, optionally with the aid of a separate annular hollow body or a disc, is applied by a shrinking or shrinking process.

4. Seal according to at least one of claims 1 to 3, characterized gekennzeich¬ net that the sealing members A and B inside or outside, in the middle or at the end of a hollow cylinder piece (5, 5 ', 15, 45, 68, 69), pipe ( 28, 29, 38, 39), ring (52, 72, 72 ', 92), flange (75, 75', 95, 95 '), container (8, 18), valve (49, 99, 99', 82) or on the outside of a disc (85) or shell (94, 94 ') and are structurally integrated. -lδ-

5. Seal according to at least one of claims 1 to 4, characterized gekenn¬ characterized in that a) the radial sealing ring (1, 11) at or near the end of a thin-walled hollow cylinder piece (5) or a bore (20) in a container wall ( 18) or is structurally integrated in a flange, and b) the hollow cylinder piece (15) or (5) without or with sealing boss (1), which is an integral part of a connecting piece (58) or (9), fits into the bore (20) or (10) is inserted, and c) the sealing lip (11, 1) is sealed by a conical pressing piece (22, 12) against the hollow cylinder piece (15) or the inner wall of the bore (4) or is pressed in, the pressing piece (22, 12) possibly remaining there.

6. Seal according to at least one of claims 1 to 4, characterized gekenn¬ characterized in that a) the sealing member A, consisting of a hollow cylinder piece (5 ', 25) with end¬ molded radial sealing valve (1'), an integral part of a Pipe connection sleeve (9) or a pipe (29), b) into or onto which a smooth pipe (7) or a pipe (28) with a conical, concave or convex taper (27) or widening on the end suitably inserted or expanded . and c) the sealing lip (1 ') or the counter surface is pressed and held radially with the aid of a union sleeve (6) with a molded press cone or an outer press cone piece (32).

7. Seal according to at least one of claims 1 to 4, characterized gekennzeich¬ net that one for connecting two pipes (38, 39) or hollow cylinder pieces (68, 69) (38, 68) is smooth, and the other (39 , 69) has at least one radial sealing hump (31, 61), both of which are pushed into one another and by subsequent narrowing of the cross section of the outer tube piece (38) in the region of the sealing humps, if appropriate by rolling, for example with curling tongs (35) or by widening the cross-section (67) of the inner hollow cylinder piece (68), e.g. are tightly and mechanically firmly connected to each other with the aid of a solid inner press cone (65).

8. Valve with radial press seal according to at least one of claims 1 to 4, characterized by the following features a) the valve seat (45) consists of a hollow cylindrical piece with radial sealing end (41), b) the axially movable valve disc (44) a cone-shaped (2) or a concave or convex spherical zone-shaped counter surface, c) the radial sealing ring (41) is pressed in the closed state by a separate press cone (42) radially against the valve disk (44).

9. A seal according to at least one ^~ mi d3er claims 1 to 8, gekennzeich¬ characterized net that for generating a zusätzHchen high pressure seal with the increase of the pressing pressure by the pressure cone (12, 6) or by an internally or externally anHegenden positive or negative pressure of the sealed Medium, the radial sealing lip (1, 1 ') is correspondingly stronger and the edge (13, 13') behind it and the wall (14, 14 ') of the hollow cylinder piece (5, 5') are also on or in the counter surface (4, 4 ') is pressed, the compressive strength being increased by increasing the wall thickness of the hollow cylinder piece (5, 5').

10. Seal according to at least one of claims 1 to 9, characterized gekenn¬ characterized in that pending the structurally integrated in the sealing members A radial sealing lips (1, 1 ', 11, 31, 41, 61), a radial sealing lip Ring (52) is inserted, the opposite, possibly more than two radial sealing lips (51, 5l ') and is held sealing by radial pressure.

11. Seal according to at least one of claims 1 to 4, characterized gekenn¬ characterized in that a) two flanges (79, 79 ') at the end or end of a hollow cylinder piece (75, 75') outside or inside radial sealing lips (71, 7l ' , l ', l "), which are concentric, axially opposite one another or at a small distance d, d', and b) against the outside or inside of a thin-walled intermediate ring (72) with a width b> d by narrowing the cross-section or expansion with the aid of a press belt (70, 77) from individual, interconnected links or a clamping ring is pressed tightly, and c) the intermediate ring has the shape of a hollow cylinder (72) or the shape (72 ') of cone or spherical zone shells (76, 76 ') or consists of a combination of these shapes for the inner and outer surfaces.

12. Seal according to at least one of claims 1 to 4, characterized gekenn¬ characterized in that a rotationally symmetrical sealing member A from at least one shell zone (94, 94 ', 104, 104', 114, 114 ') with at least one end outside and / or formed on the inside radial sealing boss (1 ', 101 to 101' ", 91, 91 ') and which is the largest by axial pressure against an axial stop (106, 106', 96, 96 ', 90, 66) or smallest cross-sectional area (Q, Q ') is widened and / or narrowed, and the radial sealing lip (1 \ 101 to 101' ", 91, 91 ') thereby radially and tightly against the concentrically opposite counter surface (4, 4 ', 2, 3, 3') of a sealing member B is pressed.

13. Seal according to claims 11 and 12, characterized in that the radial sealing humps (71, 71 ') are pressed axially against one another at a distance d = 0 or via a separate or a stop ring (66) integrated in the construction on the intermediate ring (72) and are widened in cross section by largely elastic deformation such that they are pressed radially and tightly against the stationary intermediate ring (72). - & -

14. Seal according to claim 12, characterized by the following features a) two flanges (95, 95 ', 105, 105') or tubes have at least one axial stop (96, 96 ', 106, 106') at each end transverse to their axis of rotation. next to the counter surfaces (4, 4 ', 2, 3, 3'), b) between which there is an intermediate sealing ring (92, 102) which consists of at least one shell zone (104) or shell zones (114, 114 ', 104', 104 "), on which radial sealing plugs (101 to 101 '", 91, 91') are integrally formed, c) their cross-sectional area (Q, Q ') by axially compressing the Rin ¬ tot (92, 102, 104 ') between the stops (106, 106', 96, 96 ') is reduced or enlarged, and so the sealing lugs (101 to 101' ", 91, 91 ') radially and tightly the counter surfaces (4, 4 ', 2, 3, 3') are pressed.

15. Seal according to claim 12, characterized in that for the closure of a tube, a bore or a valve (99, 99 ') a) of the closure device made of a rotationally symmetrical shell (94, 94') with a radial molded-on edge DichtHppe (l '), which b) is inserted into the locking seat (98, 98') with mating surface (4, 2), and c) the cross-sectional area (Q, Q ') of the shell (94,94') by axial Pressing against a separate axial stop (96) connected to the valve seat or against a separate plate (90) which is axially movable with respect to the shell base is expanded in such a way that the sealing step (1 ') radially and tightly against the counter surface (4, 2) is pressed.

16. Butterfly valve with radial press seal, preferably in a metal-metal version for ultra-high vacuum, according to at least one of claims 1 to 4, characterized by the following features a) the valve seat is a thin-walled spherical shell zone that is concave against the radial sealing lip (81) ( 83) with radius R or hollow cylinder zone, which is currently arranged in a hollow cylinder piece (82), b) the valve disk consists of a disc (85) that can be tilted by a diameter D ^ 2R with an externally molded radial sealing ring (81), c) in In the closed and tight state, the valve seat (83) is pressed onto the sealing boss (81) of the valve plate (85) in a peripherally uniform manner, radially from the outside with the aid of a press belt (87) made of individual, interconnected G-springs.

17. Seal according to at least one of claims 1 to 15, characterized gekenn¬ characterized in that a) the radial sealing chop (1, 11, 21, 71, 71 ') sharp-edged as a radial cutting edge or b) the radial sealing chop (l ', 81, 91, 91', 101 to 101 '") is formed.