AU681449B2

AU681449B2 - Sealing arrangement for sealing conduits

Info

Publication number: AU681449B2
Application number: AU78984/94A
Authority: AU
Inventors: Peter Ilesic
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-12-02
Filing date: 1994-11-23
Publication date: 1997-08-28
Anticipated expiration: 2014-11-23
Also published as: SI9400374A; EP0656502A2; EP0656502A3; EP0656502B1; CH685308A5; ATE191546T1; AU7898494A

Abstract

The invention relates to a sealing device for sealing pipelines for gaseous or fluid media, which contains a closable housing 4, which engages around the pipeline in the manner of a socket, and a sealing element 8 which consists of an elastomeric material, is arranged in the form of a ring in the housing 4 and exhibits an annular bead 12 which projects in the direction of the wall of the pipeline and exhibits a sealing surface which can be rested against the wall. According to the invention, the sealing element 8 contains an annular gap 13 which subdivides the annular bead 12 in the axial direction into a first radial bead 14 on the interior of the seal and into a second radial bead 18 on the exterior of the seal, the gap 13 extending from the sealing surface 15 into the annular bead 12 with such an inclination that an acute-angled sealing lip 21 is formed on the second radial bead 18 adjacent to the gap 13. The first radial bead 14 may exhibit, on the interior of the seal, an axial annular groove in the form of an undercut 16 which forms, on the radial bead 14, an acute-angled sealing lip 17 which is directed towards the interior of the seal. <IMAGE>

Description

'Uw..

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant: Peter ILE616 Invention Title: SEALING ARRANGEMENT FOR SEALING

CONDUITS

C. C S C* C C C

C.

The following statement is a full description of this invention, including the best method of performing it known to me/us: -2 Sealing arrangement for sealing con~duits The invention concerns a sealing arrangement for sealing conduits, as set forth in the classifying portion of claimi 1.

In a sealing arrangement of that kind, the housing which is in an opened and sIadma condition is arranged, with the sealing member, around a conduit or pipe which is to be sealed off. By tightening the housing, the annular bead of the sealing maxrer is mo~ved radially towards the outside of the wall of the conduit until the sealing surface of the annular bead presses against the wall of the conduit, with the required contact pressure force or sealing force. if the gaseous or liquid agent contained in the conduit is subjected to different operating pressures (reduced pressure or increased pressure), the contact pressure force with which the annular bead bears against the wall of the conduit must be adapted and adjusted for the respective differences in pressure and thus force, at the sealing surface, as between the space which is under pressure and the surrounding atmo~sphere. If an excessively low contact pressure force is applied, the seal may lose sealing integrity when the internal ~~**pressure is increased, as the annular bead which is for examp~le in the form of a circular arc lifts away from the wallI of the conduit.

It will therefore be necessary as a precaution to apply an increased contact pressure force in order to afford an adequate sealing effect, even in regard to the maximrn differences in pressure and force in the sealing region.

0 When using thin-wall pipes or conduits however, in 25 consideration of the limited strength thereof, the contact pressure force to be applied by the seal may not exceed a comparatively low value which is dependent on the strength of the conduits. That limitation on the contact pressure force to be applied is to be taken into consideration in particular when dealing with pipes of plastic material of lower strength than pipes of metal. However, as stated, that contact pressure force which is admissible only to a limited extent can result in an inadequate sealing effect, in particular when -3 the situation involves fluctuating pressures which cause the seal to be 'worked', that is to say the seal perform micro-inovements in the elastic range, and when the situation involves a low pressure or a reduced pressure in respect of the agent, when difficulties occur in term of providing a seal with conventional sealing arrangemients.

The invention is therefore based on the problem of providing a sealing arrangement of the general kind set forth, which permits a universal and durable sealing action for conduits of different materials and strengths, both at low conduit pressures and at high conduit pressures and also when the join is subjected to a high level of loading.

In a sealing arrangement of the general kind set forth, that problem is solved in that the sealing member has an annular gap which subdivides the annular bead in the axial direction into a first 15 radial bead portion at the inward side of the seal and a second radial bead portion at the outward side of the seal, wherein the gap extends from the sealing surface into the annular bead at such an inclination that an acute-angled sealing lip is formed on the second radial bead portion adjo:~igtegp Advantageous embodiments of the invention are set forth in the appendant claims.

When the sealing arrangement is fixed to a conduit, for exmple at a point on a pipe which is suffering from a leak or at the location of a conduit join, the sealing surface of the first radial 25 bead portion is caused to bear against the wall of the conduit whten the housing is tightened, so as to form a first sealing means.* The axially enlarged length of the sealing surface forms a widened sealing region so that the radial bead portion applies a low contact pressure force which loads the wall of the conduit to an admnissible degree and which is still sufficient to provide a first, inner sealing action. By virtue of the inclined gap which is arranged at an angle. relative to the longitudinal axis of the conduit, when the 0 -4sealing arrangement is tightened the first radial bead portion presses against the sealing lip of the second radial bead portion, whereby the sealing lip bears firmly against the wall of the conduit and forms an additional outer second sealing means, the sealing action of which is improved by the inwardly directed sealing lip. In that way it is also possible reliably to seal off conduits in which the agent therein is under a low pressure.

As, when the arrangement is used at a pipe join, the annular bead which provides the sealing action is not disposed in the region of action of the conduit forces (axial rmovement or torsional movement), but bears against the peripheral surface of the conduit and is pressed against it there with a controlled force, the sealing arrangement remains durably elastic by virtue of a low level of mechanical loading. In relation to pipe joins, there is no need for 15 the pipe ends to precisely butt together and the pipe ends do not have to be especially machined as the sealing member according to the V invention has a good sealing effect both on a rough surface and also on a smooth surface.

aIn an advantageous embodiment, the first radial bead portion 20 has an axial annular groove in the form of an undercut configuration, on its side which is the inward side as considered in the axial direction, that is to say, on that side of a cavity in the sealing S"arrangement, which is towards the agent that is present in the conduit and that is to be sealed off relative to the surrounding 25 atmosphere. The undercut configuration thus forms a pronounced, projecting sealing lip which converges at an acute angle. If, upon an increase in the pressure in the conduit, the pressure in the space or cavity in the sealing arrangement also increases proportionally, then pressing against the undercut configuration on the first radial bead portion, then on the one hand the projecting sealing lip is pressed substantially radially against the wall surface of the conduit while on the other hand the first radial bead portion is deformed substantially in the axial direction. That deformation, by way of the ccmpressed gap, presses inclinedly on the second radial bead portion whereby the latter presses against the wall of the conduit with an increased contact pressure force and forms an additional seal which is proportional to the increased pressure and which has a progressive sealing action.

The sealing member may have a transitional region of a recessed configuration, which adjoins the undercut configuration of the first radial bead portion in a direction towards the region of the sealing member, which is for exarrple of a cylindrical shape. The first radial bead portion can then deform more easily with a radial ccmponent as its elasticity of deformation is improved by weakening of its base in the transitional region.

If, in accordance with a further embodiment, the sealing lip 15 of the second radial bead portion is arranged displaced outwardly in a radial direction relative to the sealing surface of the first *radial bead portion, then when the sealing arrangement is tightened the sealing surface of the first radial bead portion bears first against the wall of the conduit. It is thereafter that the sealing 20 lip of the second radial bead portion bears against the wall of the conduit so that it cannot push itself under the sealing surface of "the first radial bead portion. That arrangement results in the sealing lip being in a defined position on the wall of the conduit, and that defined position, upon an increase in pressure, results in a more uniform seal being produced, with an improved sealing action, even in relation to rough or uneven surfaces.

If the sealing surface of the outer second radial bead portion is divided into an axially inclined sealing surface and a sealing surface which extends parallel to the axis of the arrangement, then, when the sealing arrangement is tightened in position, the contact pressure force in the inclined sealing surface rises approximately linearly while the sealing surface which is parallel to the axis of YI c~ -6 the arrangement bears against the wall of the conduit only slightly with a negligible contact pressure force or without any force.

Accordingly it is only necessary to apply the minimum required contact pressure force which loads the conduit with a minimum arnount of pressure in relation to surface area, without causing deformation of the conduit..

Preferably the sealing mamber is of a mirror-inage syrMtrical configuration in the axial direction. In that case the sealing mesTber can be used in a particularly desirable fashion by virtue of the radial bead portions bearing against a pipe connection at both sides thereof, as the samne sealing conditions occur at the two radial bead portions. That therefore gives a seal which is resistant to shock and impact and which is also resistant to vibration and shaking or jarring and which particularly in the case of gas conduits affords an enhanced level of safeguard against fire and explosion, as is *.indispensable for exampple in areas which are liable to earthquakes.

Preferably the sealing mem-ber is fitted into the housing loosely or with a snug or press fit involving a relatively low insertion force. In that case, when the housing is closed or upon 20 movements in respect of the ends of the conduit, the sealing member can move slightly at its periphery relative to the housing so that no *stresses are built up in the sealing member, which could restrict the *sealing action. The application of a lubricant or slip agent to the outer periphery of the sealing member and/or the inner periphery of the housing can further reduce undesired friction which would impede the compensating movement.

The invention is described in greater detail hereinafter by means of an embodiment with, reference to drawings in which: Figure 1 is a diagranmatic sectional view of a sealing arrangement according to the invention, surrounding a pipe join, Figure 2 show,%s the sealing arrangement of Figure 1 in the tightened condition with the resulting radial pressure force pattern at the sealing surface of the sealing arrangement, 7 Figure 3 is a diagrammatic sectional view of the sealing arrangement in the case of a rising pressure in the conduit, with the resulting radial pressure force pattern at the sealing surface of the sealing arrangement, and Figure 4 is a perspective view of the partially sectioned housing with the sealing arrangement in the tightened condition.

Referring to Figure i, shown therein is a pipe connection between two pipes 1 and 2 of a conduit. The pipes 1 and 2 adjoin each other with their respective open ends which face towards each other.

They can be fitted with a gap 3 or in butting relationship without a gap or only with a small gap. Likewise the pipe connection can be formed for example by screwing or by the pipe ends being fitted one into the other (not shown). A simple connection of that kind is not gas-tight or fluid-tight so that leakages can occur due to escape of tCie agent contained in the conduit.

The drawings show the pipe connection with a gap 3 in order clearly to indicate the possibility of the agent in the conduit escaping therefrcm. The sealing arrangement which is designed symetrically relative to a line or cross-sectional area as indicated at A-A in Figure 1 is only shown in the drawings with its middle region and its right-hand half. The specific embodiment described hereinafter is described witl. reference to the geometry in relation to a sectional view, but is intended to relate to a rotationally symmetrical sealing arrangement.

S 25 A housing 4 is of a substantially rotationally symmetrical configuration in the manner of a sleeve or a pipe clamp and is provided with a mechanical closure device so that it can be fixed to a pipe or conduit by embracing around same. In the initially slack condition the housing 4 is arranged approximately centrally over the pipe connection, that is to say over the gap 3. The two axial ends 6 of the. housing 4 are then disposed over the end regions of the pipes 1 and 2. At each of its ends 6 the housing 4 has a radially inwardly extending terminal wall 7.

r-r 8 Fitted in the interior of the housing 4 is a rotationally synmetrical, annular sealing member 8 of elastcmer material which is in the form of a sleeve member. The sealing member 8 bears with its outside against the inside periphery of the housing 4. Before the sealing member 8 is fitted into the housing 4, a lubricant paste or a similar lubricating material can be applied to the outside of the sealing member 8 or the inside of the housing 4.

In the present description of the sealing arrangement the term inside diameter or the term inside radius denotes the inside dimension of the sealing member 8 at a respective cross-section. In a first middle region 9 which engages over the connection between the pipes 1 and 2, the sealing member 8 is of an inside diameter which is larger than the outside diameter of the pipes 1 and 2 so that a substantially annular cavity 10 remains on the inward side of the 15 seal, between the middle region 9 of the sealing member 8 and the outside walls or surfaces of the pipes 1 and 2, even when the housing 4 is in the tightened condition, as shown in Figure 2.

Adjoining the middle region 9 in the axial direction is a transitional region 11 which is of larger inside diameter than the 20 middle region 9 of the sealing member. That transitional region 11 can be in the form of an annular groove with inclined or bevelled side walls or of a cross-section in the form of a circular arc or similar shape. The transitional region 11 goes into a sealing annular bead 12 of smaller inside diameter which is subdivided into two bead portions, more specifically the radial bead portions 14 and 18, by a recess in the form of a narrow slot-like groove or annular gap 13.

The first radial bead portion 14 adjoins the transitional region 11 in the axial direction. The radial bead portion 14 has a sealing surface 15 which extends substantially parallel to the surface of the conduit, in an axial direction, to the gap 13.

Provided on the radial bead portion 14, towards the transitional region 11, is an axial groove in the form of an undercut 9config.ration 16 which, in a direction towards the pipe 2, goes into the sealing surface 15 of the radial bead portion 14, that configuration forming a projecting, acute-angled sealing lip 17 which faces approximately axially inwardly towards the pipe connection.

When considered axially, that is to say when viewing towards the right in Figure 1, the gap 13 extends at an obtuse angle which can be for exanple between about 1100 and 1300 frcm the sealing surface 15 of the radial bead portion 14 into the interior of the sealing member 8 or the annular bead 12. The greatest depth or the greatest diameter of the gap 13 approximately corresponds to the inside diameter of the middle region 9 of the sealing member 8.

The axially adjoining region of the sealing member 8, which *extends from the gap 13 to the terminal wall 7 of the housing 4, forms the second radial bead portion 18. The second radial bead 15 portion 18 has a first sealing surface 19 which, with the side wall 20 of the radial bead portion 18 which is defined by the gap 13, form a sealing lip 21 which converges at an acute angle. The inside diameter defined by the front edge of the sealing. lip 21 is Lwi~ V'than the diameter of the adjacent outer edge 22 of the radial bead portion 14, said edge 22 being formed as the boundary line between the sealing surface 15 of the radial bead portion 14 and the gap 13.

The first sealing surface 19 extends with an enlarging diameter in the axial direction and goes into a second sealing surface 23 which extends with a constant diameter as far as the terminal wall 7 of the housing 4.

The sealing member 8 is of mirror-image syinmtri-,al configuration and at its left-hand end region (not shown) has an annular bead corresponding to the annular bead 12, in a mirror-image symmetrical arrangement.

For clamping the sealing arrangement in position, the housing 4 is tightened for example by a screw closure (not shown) so that the 10 housing 4 is pressed in a radial direction against the pipe 2 and against the pipe l,the radial bead portion 14 bearing with its sealing surface 15 against the pipe 2. By the housing 4 being further tightened, the radial bead portion 14 is radially compressed, with elastic deformation of its rubber-like or springy material, in which case its side surface which is towards the gap 13 fills the gap 13, ccmes to bear against the side wall 20 of the second radial bead portion 18 and presses against the side wall 20. The housing 14 is radially tightened until the second sealing surface 23 of the radial bead portion 18 bears against the pipe 2 without any pressure or with a slight pressure. The side region of the radial bead portion 14, which is towards the gap 13, then also presses against the second radial bead portion 18 and the sealing lip 21, thus resulting in the sealing member 8 being in the clamped condition shown in Figure 2 S 15 with the pressure pattern at the sealing surfaces 15, 19 and 23, which arises by virtue of the specific geometry of the radial bead portions 14 and 18. In the operation of tightening the sealing arrangement therefore the arrangement produces a dual sealing action, insofar as on the one hand the sealing surface 15 of the radial bead 20 portion 14 and the sealing surface 19 of the radial bead portion 18 e••o press against the pipe 2, and on the other hand the radial bead portion 14, filling the gap 13, additionally presses against the radial bead portion 18 and iin particular the sealing lip 21 thereof S. and thus produces a second sealing effect. That affords a reliable fil.a, delicate sealing action even in relation to a low pressure in the conduit and in relation to vacurt if only a low contact pressure force is applied at the annular bead 12.

If the pressure as indicated at p in Figure 3 of the agent in the conduit rises, the pressure in the cavity 10 also increases proportionally. That pressure p applies a force to the side of the radial bead portion 14, which is towards the cavity 10, constituted a 11 by the transitional region 11 and the undercut configuration 16, so that the sealing lip 17 and the sealing surface 15 are additionally pressed against the surface of the pipe 2 by the above-described elastic deformation. of the radial bead portion 14. Therefore, by virtue of the undercut configuration, the radial bead portion 14 can also be deformed radially against the pipe 2, upon an increase in the pressure in the agent in the conduit and thus an increase in the pressure ir the cavity 10. The pressure p also results in additional defonmtion or curvature of the radial bead portion 14 in the axial direction so that it presses against the radial bead portion 18 e-'d in particular the sealing lip 21 thereof and thus results in an increase ini the contact pressure force applied by the sealing men~er 8 with its annular bead 12 against the pipe 2. The resulting pressure pattern at the sealing surfaces 15, 19 *and 23 is diagranmatically 15 shown. in Figure 3, in which reference P, in the direction indicated by the arrow, denotes the force produced by the clamping action of the sealing arrangement, in the sealing annular bead 12, while p denotes the force producErl by the rising pressure. Thus, with a low initial pressure in the conduit, it may be sufficient to have a low contact pressure force which does not have to be designed for a maximum pressure and which therefore applies only a low loading to the wall of the conduit, whilIe with an increasing pressure the :4.*contact pressuri force or the sealing force is increased 25concomitantly therewith.

The housing 4 of the sealing arrangement as well as the closure mwbers and clamping screws preferably comprise metal, mrore especially high-quality stainless steel.

The sealing member or sealing sleeve 8 comprises synthetic rubber .which is selected in dependence the respective agent involved. Thus an EPDMv-rubber (ethylene-propylene-diene elastcmer) is suitable for all qualities of water, for waste water or sewage, air, 12 solids and chemical products, while an NBR-rubber (acrylonitrilebutadiene elastcmer) is used in relation to gas, oil, fuels and propellants and other hydrocarbons.

As described, the sealing arrangement can be used for sealing off a connection between two pipes of a conduit, which are to be joined together. In that case the two pipes can be fixed in their mutual positions by holding means so that the sealing arr3ngement is essentially restricted to the function of providing a sealing action.

The sealing arrangement however may also perform the function of holding the ends of the pipes 1 and 2, for example in relation to freely laid waste water or sewage pipes, in which case it then holds the ends of the pipes in mutually centered relationship.

The sealing arrangement according to the invention can bridge over and seal off both a leaky point in a pipe or conduit and also a narrow or wide gap between the ends of adjoining pipe portions of a pipe join so that the sealnrg arrangement can be used as a lengthcompensating means. The sealing arrangement is also suitable when the axes of the end portions of the adjoining pipes are displaced in a radial direction, when the ends of the pipe portions are angularly displaced, and when the ends of the pipe portions involve a a rotational movement in opposite relationship, as well as in relation to different pipe diameters.

The sealing arrangement can be used with many pipe materials Thus the pipes may comprise steel, including longitudinally welded or S 25 spiral-welded, non-ferrous metal such as aluminium, copper and alloys thereof, plastic material such as PE, PP, PV, ABS, or glass fiberreinforced plastic (GRP), or other materials such as glass, fiber cement or ceramic.

The housing 4 and the sealing member 8 may be designed to be divided in a longitudinal plane at one half thereof or continuously so that the sealing arrangement can be completely divided or can be

_MEMW

13 pivoted about a hinge disposed on the housing. In that case the sealing arrangement is particularly easy to fit as the pipes which are to be sealed thereby do not have to be separated from each other.

In particular the sealing arrangement can be used as a repair assembly on a leaking pipe.

If the plane of division or separation which passes through the longitudinal axis of the sealing arrangement is displaced through an angle relative to the longitudinal axis, between the two radial bead portions 14 and 18, that avoids the existence of a rectilinear continuous sepax-ting gap in the region of the annular bead 12. That means that the improved sealing action is still retained.

The sealing rember which has been described in relation to a *rotationally symmetrical sealing arrangement can also be of a horizontal, flat configuration, in which case the geometries of the 15 xadial bead portions are transferred to a flat sealing arrangement.

9.

99*9 9 9

Claims

1. A sealing arrangement for sealing conduits for gaseous or fluid agents, which includes a closable housing which fits sleeve-like around the conduit, and a sealing member which comprises elastomer material, is arranged in the housing in an annular configuration and has an annular bead which projects towards the wall of the conduit and has a sealing surface which can be applied against the wall, characterised in that the annular bead is subdivided into a first or inner radial bead portion and a second or outer radial bead portion by an annular gap which extends from the sealing surface into the annular bead at such an inclination that an acute-angled sealing lip is formed on the second radial bead portion adjoining the gap, and that the gap is closable by elastic deformation of the first or inner radial bead portion forcing the outer sealing lip against the wall of the conduit.

2. A sealing arrangement as set forth in claim 1 characterised in that the first radial bead portion has an axial annular groove in the form of an undercut configuration which on the first radial bead portion forms an acute-angled inner sealing lip which is directed 25 inwardly of the seal.

3. A sealing arrangement as set forth in claim 1 or claim 2 characterised in that the sealing member has a recessed transitional region which adjoins the undercut 30 configuration of the first radial bead portion.

4. A sealing arrangement as set forth in any on. of ot'o claims 1 to 3 characterised in that the front edge of the outer sealing lip is displaced radially outwardly relative to the sealing surface of the first radial bead portion. \\MELBo1\home\Luia\Keep\78984-94.doc 11/06/97 I Ir I I 15 A sealing arrangement as set forth in any one of claims 1 to 4 characterised in that the second radial bead portion has a first sealing surface which is inclined in the axial direction and which expands radially and a second sealing surface which adjoins the first sealing surface and which extends in the axial direction substantially with a constant diameter to an outer terminal wall of the housing.

6. A sealing arrangement as set forth in any one of claims 1 to 5 characterised in that at each of its two axial edge regions the sealing member has a respective annular bead, the two annular beads being of a mirror-image symmetrical configuration relative to each other.

7. A sealing arrangement as set forth in anyone of claims 1 to 6 characterised in that the housing has a clamping means arranged at its outer periphery.

8. A sealing arrangement as set forth in any one of claims 1 to 7 characterised in that the sealing member is fitted in the housing loosely or with a snug fit.

9. A sealing arrangement as set forth in any one of claims 1 to 8 characterised in that a friction-reducing 25 means is applied to the outer periphery of the sealing o member and/or the inner periphery of the housing. of *i \\HEL.BOI\home$\Lluisa\Kep\78984-94 doo 11/06/97 iM 16 A sealing arrangement as set forth in any one of claims 1 to 9 characterised in that the elastomer material of the sealing member is an EPDM-rubber (ethylene- propylene-diene elastomer) or an NER-rubber (acrylonitrile butadiene elastomer). Dated this 12th day of June 1997 Peter ILESIC By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent Attorneys of Australia \\MELB0\home\L~uisa\Keep\7e984-94 .doc 19106/97 ABSTRACT The invention concerns a sealing arrangement for sealing conduits for gaseous or fluid agents, including a closable housing which fits sleeve-like around the conduit and a sealing member which comprises elastomer material, is arranged in the housing in an annular configuration and has an annular bead which projects towards the wall of the conduit and has a sealing surface which can be applied against the wall. According to the invention the sealing member has an annular gap (13) which subdivides the annular bead (12) in the axial direction into a first radial bead portion (14) at the inward side of the seal and a second radial bead portion (18) at the outward side of the seal, wherein the gap (13) extends from the sealing surface :into the annular bead (12) at such an inclination that an acute-angled sealing lip (21) is formed on the second radial bead portion (18) adjoining the gap At the inward side of the seal the first radial bead (14) can have an axial annular groove in the form of an undercut configuration (16) which on the radial bead portion (14) forms an acute-angled sealing lip (17) which is directed inwardly of the seal. (Figure 1) rl ICI~-i-~-