CA1054646A

CA1054646A - Pipe connection

Info

Publication number: CA1054646A
Application number: CA268913A
Authority: CA
Inventors: Werner Hartmann
Original assignee: Centaurus AG
Current assignee: Centaurus AG
Priority date: 1976-07-08
Filing date: 1976-12-30
Publication date: 1979-05-15
Also published as: HU176933B; CH623391A5; GB1520390A; DE2630814A1; NO764174L; DE2630814C3; PL116002B1; GR66490B; BR7700774A; DE2630814B2; JPS536919A; FR2357810B1; PT65967A; IT1068629B; FI763699A; ZA767667B; IL51206A; FR2357810A1; EG13212A; TR19937A

Abstract

ABSTRACT OF THE DISCLOSURE

The invention relates to a pipe connection for unprepared pipe ends with a sealing sleeve made of a plastics material which is pushed on to the pipe ends in line with one another and abutting one another the outer surfaces of which widens conically both ends to an axially central periphery onto which outer surfaces are pushed from both ends flange rings which are clampable to one another.

Description

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The inven~l.cn relates to a pi.pe connection for unprepared pipe ends Witil a sealing sleeve made of a plastics material which is pushed onto the plpe encls in line with one another and abutting one another, the outer surfaces of which wlden conically at both ends to an ax:ially central periphery, onto which outer surfaces are .:
pushed from both ends flange rîngs which are clampable to one an o thQ r . ': .
Such a pipe connection is advantageous in that pipes can be tightly connected to one another without any further preparation by, for example, flanges etc. welded on.
It has already been proposed to make a sealing sleeve of flexible, but elastic material, perferably steel.
. Such a material is not, however, suitable in practice because the forming pressures to be used in order to achieve a practically satisfactory s.ealing are not available at a building site. For th;s purpose the elasticity of steel is too great.
The present invention is based on the problem of proposing '! a pipe connection of the above-men-tioned type, the sealing properties :1 and life of which are improved compared with the already proposed pipe connections.
. Th.is i.s achieved in part according to the invention in that the plasti.cs material of the sealing sleeve consists of polyolefines with a crystalline portion which does not exceed 24%. ~;

~ By the use of polyolefines h.aving a low K-value, that is, i with a low crystalline value it is observed that the material upon ., clamping becomes amorphous and the crystalline material upon clamping cannot ~low away. The material then attains a resetting possibility.
. Due to the cl.amping of the flange rings the material flows :, to the annular gap to be sealed so that the pipes are firmly pressed '' Ib~ ., :, ',~' .

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S46~6 together at their front edges.
Experiments have shown thaL pipe connections according to the present invention are loadable up to pressures in the order of 9~-98 Kg. per square cm. inner pressure beEore one of the pipes due to tile inner pressure is slid axially out of the sealing sleeve.
It is possible to provide a projection at the centre of the inner diameter of the sealing sleeve, the projection serving as a stop. The diameter of the projection is somewhat smaller than the outer diameter of the ends of the pipe preferably by about 0.3 mm. so that as upon cla~ping the flange rings the accumulation of .
material of the sealing sleeve goes outwards so that the front ends of the pipes lie firmly against one another and are surrounded to a certain extent by a sealing beading.
Another problem solved by the invention consists in that pipe connections can also be ma;ntainable in respect of large pressures and rapidly assembled when it is necessary to accommodate greater differences between the diameter of the pipes to be connected by means of the pipe connection.
According to a further feature of the invention it is ef~eceed that the outer ~ace of the sealing sleeve is proEiled annularly.
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By means of these proEiled rings which run conically to the sealing sleeve or at least substantiall~ coaxially therewith, upon clamping, that is, with the action of pressure on the sealing x sleeve from outside directed inwards, a greater pressure will be ~, reali~ed in the region of these annular rings or guide faces.
Because the plastics material is capable of ~lowing, the pressure acting on the profiled rings on the outer face of the sealing s]eeve forces the plastics material to flow substantially radially .'i , ' 3B '' .
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~o the ins-ide of the sealing sleeve wllere it :is formed -lnto a corresponding allnula-r beading abutting the pipe ends.
These constr~lctions solve the problem of the invention, t~-at i~ they form a tight seal even with non-circuLar pipes or pipes With different outer diameters.
The tightness of the connection is further increased when a ring is provided between the p:ipe ends flush with each other.
This ring which consists, for example, of elastic flexible material additionally levels any unevennesses on the front faces of the pipes.
For the centering and holding of this ring when mounting ~.
the sealing sleeve the sealing sleeve may be provided on its inner periphery with a nose piece which engages in a recess on the outer periphery of the ring.
The nose piece is held centrally on the ring by the clamping procedure. The material of which the nose piece consists thereby flows at least partially in an outward radial direction.
Essential only is that the profiling of the sealing ` sleeve is affected such that flow guide surfaces for the m~terial -of the sealing sleeve under pressure are formed which then cause and arrange th-ls material for the forming of sealing rings on the outer diameters of the pip~s to be connected.
In summary of the above, therefore, the present inventîon may be broadly defined as providing in combinatlon with two axially aligned pipes having unprepared ends adjacent one another, a pipe connection for coupling the pipe ends and comprising a sealing sleeve closely surrounding the aligned pipeends and having a length extending over both pipe ends, the sealing sleeve consisting of a plastic material capable of cold flow under the effects of pressure, the material being a polyoleEine plastic with a crystalline portion .

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; . .. .: . '~ . ~, ' ~ ' S~46 ~hici~ does not exceed 2~1~, Lhc outer face oE the seali~g sleeve widening conLcalLy in an axinl direction Erom both ends to the sleeve center and having a plurality annularly stepped guide faces therein, a pair of Elange rings each surrounding and embracing a conical face of the sealing sleeve over one of the pipe ends, and means for clamping ~he Elange rings together causing pressure to be exerted on the stepped guide faces of the sealing sleeve until the plastic material ~lows and is permanently deformed to form a beading around the outer diameter of the pipe ends 9 thereby causing the pipe ends to be tightly sealed to one another.
The invention will be described with reference to the accompanying drawings.
Fig. l shows a longitudinal section through the essential constructional elements of the pipe connection according to the invention, in which the left side shows a sealing sleeve for pipes of approximately the same diameter to be connected and the right ., ; partially sectioned side, for pipes o~ different outer diameter.

~ Fig. 2 shows a pîpe 2 according to Fig. l.

'~ Fig, 3 shows a longitudinal section corresponding to ' Fig. l with a ring between the par-ts to be connected to one another.

~ In Fig. l the two pipe5 l and 2 to be connected to ane '' another which have the same outer diameter are inserted in the ends :i , o$ a sealing sleeve 3 opposite one another. The sealing sleeve 3 has preferably an inner diameter corresponding to the outer-diameter of the pipes l and 2 to be connected to one another when pipes with ' the same outer diameter are to be connected. The play between the outer periphery of the pipes and the inner diameter o~ the sealing sleeve should preferably not be greater than l mm. The loadability ,~
y of the pipe connection depends essentially on whether the play is as : ' ' , : ...................... . :

:; ~ ' l~S~:i9~6 slilal:L as possible, i E ~;ea:L-ing s:leeves are used tlle inner and outer faces are smooth. In order to bring the ends of the pipes 1 and 2 in contact against one another as far as possible at the middle of the ax:ial lengtil of the sealillg sleeve 3 there is formed a radially in~ard projoccing ~`' ,. . . .
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annular lip 4 could also consist of a simple nipple or the like and serve to form a stop when pushing one pipe end into the sealiny sleeve. The annular lip 4 should therefore have as small an axial width as possible so that the pipe ends about as closely on one another as possible.
; The sealing sleeve 3 has besides its smooth inner face 27 on its short outer face two conical outer surfaces 5 and 6 which ; preferably have the same angle of slope with respect to the longitudinal axis of the sealing sleeve 3. If pipes have different wall thickne~ses or even having different outer diameters are to be connected to one another then it may also prove advisable to select -different angles of slope for the two conical outer surfaces 5 and 6.
The conical outer surfaces 5 and 6 widen towards the centre of the sealing sleeve and intersect in a central periphery 7.
~ This centre periphery 7 is drawn in Fig. 1 as an imaginary section `l line of the extended outer sur~ace .
This section line of the two conical outer surfaces 5 and 6 should be axially outwards of the annular lip 4 and thus of the Z0 abutting plane of the two pipe ends 1 and 2.
The use of elastomer materials for the sealing sleeve 3 and slope angles between 3 and 10 for the conical outer surfaces 5 and 6 have proved suitable independently of the inner diameters of the pipes to be connected to one another.
The best results have however been had with an angle of inclination of 5. This is true in particular when the sealing sleeve 3 consists of a thermo plastic material namely of polyolefines with a crystalline portion of less than 24% by weight.

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S~6~6 Flange rings 12 and 13 are pushed onto the conical outer surfaces 5 and 6 of the sealing sleeve 3. The flange rings are formed conically on their inner faces 14, 15 so that the angle of inclination of this cone corresponds substantially with the angle of inclination of the associated conical outer surfaces 5 and 6 respecti~ely~ The cone angle of these inner faces 14 and 15 of the flange rings 12 and 13 may however also be somewhat greater than the slope angle of these outer surfaces 5 and 6. The axial length A corresponds preferably to half the inner diameter of the associated pipe to be connected. The conical outer surfaces 5 and 6 have such an axial length that the conical inner faces 14 and 15 respectively of the asso_iated flange ring when pushed into the sealing sleeve 3 contacts substantially over the whole of the conical outer surfaces 5 and 6 respectively.
The inner faces 14 and 1~ preferably correspond in their slope angles to the outer surfaces 5 and 6 of the s~aling sleeve. ;~
`The flanges 23 and 24 of the flange rings 12 and 13 are preferably selected so that the distance C between the flange faces 17 and 18 facing each other are equal to or greater than twice the axial widtll B of the flanges 23 and 24 when the flange rings are pushed onto the conical outer surfaces of the sealing sleeve 3 and are not yet clamped to one another.
In the making of the pipe connection shown in Fig. 1 the sealing sleeve 3 is provided on which the flange rings 12 and 13 are placed. In the sealing sleeve 3 the pipes 1 and 2 to be connected to one another are inserted as far as the stop on the -annular lip 4. The nuts 31 are then tightened on the screws 30 so that the flange rings 12 and 13 are moved towards one another in an .

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L6J 54S~6 axial direction. Thus on the sealing sleeve 3 a mainly radial force is exercised against the outer periphery of the pipe ends 1 and 2.
The material of the sealing slee~e 3 thus begins to flow towards the pipes 1 and 2 and with still further increasing pressure with a further clamping of the flange rings 12 and 13 finally completely consolidate against one another. After this consolidation the material of the sealing sleeve 3 the connection itself remains, when the flange rings 12 and 13 have been removed again and exists as a firm pipe connection.
The annular lip 4, taking into consideration the tolerances of the outer diameters of the pipes 1 and 2, extends only a small , distance onto the annular gap, for example, 0.2 to 0.4 mm in order to arriYe at the front edges of the pipes lying firmly against another and are surrounded by a sealing beading of the plastic material.
The profiling o the sealing sleeve in particular in the ; region of the centre periphery 7 may also be effected otherwise thanas illustrated, for example, by a collar of triangular cross sec- ;
tion.
In this case the inner faces 14 and 15 of the flange rings may be correspondingly profiled.
Pipes with different wall thicknesses and/or diameters are connected durably to one another in a similar manner.
If one wishes to compensate the greater differences between the outer diameter of the pipes to be connected by the pipe connection then the pipe connection is formed in principle as shown on the right in FigO 1 and in Fig. 2. Like the sealing sleeve shown in Fig. 1 on the left side the sealing sleeve has a : ~ : .: . ;
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, ' '' . ' - ' ~: ' ~ 5~1L6~6 substantially smooth inner face 28. The outer face 16 of the seal-ing sleeve rises from the outside inwards to a central periphery 7 similarly substantially conical.
According to the invention however on the outer face 16 steps 17 are formed which are shown enlarged ini Fig. 2 and which extend annularly around the axis 18 of the sealing sleeve 3. Fig. 2 shows in addition a flange ring 13 of an annular flange widening conically to the centre periphery 7. This annular flange with an identical flange ring 12 is screwed on the other pipe 1 so that a force is exercised in the direction of the arrow 20 as described for ~ ~' Fig. 1 and due to the concentricity of the flange rings 12, 13 a force is exercised that is, in the direction of the arrow 21 on the projecting parts of the steps 17. In spite of possible play 22 between the inner face 28 of the sealing slaeve 3 and the outer face of the pipe 1 and/or 2 there are formed by the force in the direc-tion of the arrow 21 on the inside face 15 of the sealing sleeve 3 annular beadings 10 which lie behind one another and effect a com- ;
plete labyrinth like sealing of the pipe connection even with non-` circular pipes or pipes with different outer diameters within ~-~ 20 certain limits.
Fig. 3 shows an additional ring 9 on the outer periphery of which a groove 8 is cut. A nose 29 on the inner face of the . .
centre periphery 7 of the sealing sleeve 3 corresponds to the profile of the groove. The ring 9 is maintained in position on the nose 29 until by clamping of the flange ring in the direction of the arrow 20 with the right hand pipe and in contradirection to the arrow 20 for the left hand pipe the sealing sleeve is compressed.

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~5~ 6 Thus the nose 21 moves radially outwards and the ring 9 effects a satisfactory sealing in the gap between the two rings in spite of any irregularities in the surfaces and front sides of the rings 1 and 2. The embodiment with the ring 9 as shown in Fig. 3 may be formed with or without the step-like projections 17 according to Figs. 1 and 2. It is also not necessary for the force to be applied in the dixection 20 by the screwing of flanges on the flange rings.
It is essential that the outer face 16 should be concentric with the sealing sleeve 3 and the corresponding concentricity of the flange ring 12, 13 serving for producing the clamping. Instead of screws the force can be applied in the direction of the arrow 20 and in contradirection of the arrow 20 also by other means, for example, via piston, cylinder units or other drives.
The material of the sealing sleeve 3 may also be a material which consists of polyolefines of crystalline form which does not exceed 24% or also any other rnaterial in so far as it flows under pressure and then consolidates.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In combination with two axially aligned pipes having unprepared ends adjacent one another, a pipe connection for coupling the pipe ends and comprising a sealing sleeve closely surrounding the aligned pipe ends and having a length extending over both pipe ends, said sealing sleeve consisting of a plastic material capable of cold flow under the effects of pressure, said material being a polyolefine plastic with a crystalline portion which does not exceed 24%, the outer face of said sealing sleeve widening conically in an axial direction from both ends to the sleeve center and having a plurality annularly stepped guide faces therein, a pair of flange rings each surrounding and embracing a conical face of the sealing sleeve over one of the pipe ends, and means for clamping the flange rings together causing pressure to be exerted on the stepped guide faces of the sealing sleeve until the plastic material flows and is permanently deformed to form a beading around the outer diameter of the pipe ends, thereby causing the pipe ends to be tightly sealed to one another.

2. The combination of claim 1 and further comprising a ring located within the sealing sleeve and between and abutting the pipe ends.

3. The combination of claim 2 wherein said ring has a recess on its outer periphery, and said sealing sleeve has at its center an inwardly projecting nose engaging the ring recess.

4. The combination of claim 1 wherein the sealing sleeve has substantially at the center of its inner periphery an inwardly projecting annular lip against which the pipe ends abut, the inner diameter of said lip being less than the outer diameter of the pipe ends.

5. The combination of claim 4 wherein the said annular lip projects inwardly between the pipe ends by an amount equal to 0.2 to 0.4 mm.

6. The combination of claim 1 wherein the sealing sleeve at its center has a triangular cross-section.