FR2685424A1 - COUPLING UNITS UNDER PRESSURE AND THEIR SEALING MEANS AND THE USE THEREOF IN A HIGH PRESSURE FLUID FILTRATION SYSTEM. - Google Patents

Abstract

These sealing means (1) comprise a first and a second conical surface (6, 9) formed, respectively, on a first and on a second coupling member (10, 11) and extending around a central axis (20) thereof, these conical surfaces contacting each other in an annular contact region (13) and the cone angle, measured with respect to this axis, of the second conical surface being more greater than the cone angle of the first conical surface; they also include an O-ring (2) coming into contact with the first and the second coupling member in a region immediately adjacent, in the axial direction, to the region of annular contact of the conical surfaces.

Description

Couplings under pressure and their sealing means, and

  Use of these organs in a high pressure fluid filtration system The present invention relates to sealing means

  suitability for elements that have to bear a pressure

  The invention also relates to an application of the pressure connection means to the filtration of a fluid.

  medium to high pressure in a wire system

trage.

  The use of O-rings in elastic material

  as a means of sealing fluid between two coupled components is well known in the art The O-ring is normally placed in a groove or channel provided on the central element of the two elements to be joined. Due to the machining tolerances, there are a slight play between the members to be coupled Under the effect of the pressure, the O-ring deforms, partially leaves the groove

  joins and enters the set or extrusion interval

  This effect, called "extrusion" can lead to failure of the O-ring, for example under

  form of chipping or nibbling of the over-

face of the O-ring.

  One of the methods of avoiding such

  failure consists in providing an additional seal

  shutter reinforcement of greater hardness, which prevents

  the O-ring to enter the extru-

if we.

  There is a need, always present, to develop

  new sealing configurations

  tion, in particular for medium to high pressure fluid systems, which significantly reduces the effects of the problem of failure of the O-rings. One of the aims of the present invention is to provide sealing means making it possible to practically eliminate the interval of Another object of the present invention is to provide means for connecting the O-ring.

  pressure using these sealing means and necessary

  locating a minimum number of connecting elements.

  Another object of the invention is to propose a system

  high pressure fluid filtration system

  use of pressure connection means.

  In accordance with the present invention, it is pro-

  installed sealing means for organs

  coupling to withstand pressure,

  taking a first and a second conical surface formed, respectively, on a first and on a second coupling member and extending around a central axis of the latter The cone angles of the surfaces, measured with respect to the central axis , are

  such that the angle of the second surface is slight-

  higher, preferably greater than 1 to 100, very preferably approximately 50, at the angle of the

first surface.

  Providing slight angles for surfaces

  are different, the contact surface of the two coupling members is in a region

  annular around the central axis With this confi-

  guration, there is no gap between the

  two coupling elements, which are in material contact

direct riel.

  The sealing means also preferably comprise an O-ring coming into contact with

  the two coupling members, the con-

  tact then being shifted upstream from the high side

  pressure of the annular contact region of the over-

conical faces.

  There are also proposed, according to the invention, pressure connection means o the first and the second coupling member, each comprising internal volumes making it possible to define a step

  The first coupling member pos-

  has a threaded outer part which, in the connected state, cooperates with a threaded inner part of the second coupling member The threaded and threaded portions are preferably arranged on the coupling members with an axial offset by

  with respect to the first and second confined surfaces

  that in order to stress the conical surfaces

  in contact to obtain close material contact.

  The connection means have the advantage of comprising only two parts joined by a connection

  preferably the threaded and threaded parts

  are located on the dry side of the seal, which reduces the risk of possible contamination during

  assembly or disassembly of the fitting.

  Another advantage of the sealing means and connection means of the present invention

  is due to the fact that due to the tightness by

  tact of conical surfaces, the machining tolerances of the two coupling members can be less rigorous This reduces the cost of

  manufacture of coupling elements.

  Other purposes and advantages of the present invention

  tion will appear on reading the description

  detailed which will follow from an exemplary embodiment,

  made with reference to the accompanying drawings.

  Figure 1 shows an embodiment of the

  sealing means of the present invention.

  Figure 2 shows an embodiment of the pressure connection means of the present invention, when one of the coupling members is a filter bell. Referring to FIG. 1, there is illustrated an embodiment of the sealing means 1, configured so as to form a seal between the coupling members 10 and 11 having to withstand the pressure. FIG. 1 shows a embodiment in which a part of the first coupling member 10, which has a central axis 20, is arranged coaxially in a part of the second coupling member

  coupling 11 The first coupling member 10 pos-

  sedes a conical or frustoconical surface 6, which

  extends around the central axis 20.

  A second conical or frustoconical surface 9 is disposed on the second coupling member 11 and is in partial contact with the first surface 6 As can be seen in FIG. 1, the cone angle of the second conical surface 9, by relative to axis 20, is greater than the corresponding angle of

the first conical surface 6.

  The surfaces 6 and 9 come into contact with each other in a region 13 which extends in a

  annular configuration around the central axis 20.

  The radial extent of the contact region 20 will be less than the radial extent of either of the two conical surfaces. The radial contact distance on the surfaces will also depend on the difference in the cone angles of the two surfaces En in other words, the smaller the difference, the larger the radial dimension of the

annular contact region.

  The cone angle of the first conical surface is, relative to the axis 20, preferably between 30 and 450, very preferably between 150 and The cone angle of the second conical surface is, nominally, from 1 to 100 greater than the angle

  cone of the first surface, preferably greater than

about 50.

  As can be easily seen in Figure 1, the two coupling members, when they come to cooperate, make a material contact.

  of the configuration of the inclined contact surfaces

  born, the machining tolerances of the two coupling members, for example their diameters, can be widened or, at the very least, do not need to be as rigorous One eliminates any clearance gap or tolerance interval in the contact region. In another embodiment, an O-ring is provided in contact with the first and the second coupling member, with a contact zone offset upstream from the high pressure side of the annular contact region. As can be seen on the Figure 1, the high pressure side is referenced ja and the low pressure side is referenced D The contact surface of the O-ring 2 with the second member

  coupling 11 is preferably immediately adjacent

  cente to the annular contact region 13 of the two

  conical surfaces In this way there is no essential

  no extrusion or inter-

  play valley downstream of the O-ring 2 The O-ring 2 is preferably arranged in an annular groove 3 on an outer surface of the first coupling member 10 The groove 3 is preferably offset to an adjacent position, in the axial direction , at the inner edge of the first surface

conical 6.

  Figure 2 shows an embodiment of the pressure connection means according to the present invention The first coupling member 4 of this embodiment has an internal volume 14, and the second coupling member 7 has an internal volume 17 The two volumes communicate from

  so as to constitute a fluid passage The pre-

  mier organ 4 also has an external part

  threaded laughter 5 which comes to cooperate with a part

  internal thread 8 of the second cover member

track 7.

  The threaded and threaded parts 5 and 8 are available

  seated on the coupling members with an offset

  axial with respect to the first and second sur-

  conical face of the sealing means 1, so that

  stress these contacting surfaces during screwing.

  The two parts will materially come into abutment against each other and remain in contact during operation when the correct torque has been

applied and maintained.

  As can also be seen in Figure 2, the threaded and threaded parts 5 and 8 of the coupling members 4 and 7 are arranged downstream or on the side

  low pressure sealing means 1 This cor-

  corresponds to the low pressure side h in Figure 1 The

  nets are therefore not exposed to the fluid under pressure

  sion crossing the interior volumes 14 and 17.

  The embodiment shown in FIG. 2 illustrates the use of the pressure connection means

  in a high pressure fluid filtration system

  The first coupling member 4 has a filtering bell where it is possible to put a

  filter element (not shown) in volume 14.

  In this embodiment, the second coupling member 7 is a filter head which delivers the

fluid to be filtered via volume 17.

  The pressure connection means are particularly useful in this fluid filtration system. These means comprise only two parts to be screwed in. The tolerances of the elements mentioned above need not be very strict In addition, the groove 3 of the O-ring can

  also be machined to normal tolerances.

  The materials of the filter housing and the filter head will normally be carbon steel,

  ductile steel or stainless steel-

corn.

  Integrity tests, in the form of fatigue tests, were subjected to the embodiment illustrated in FIG. 2 of the pressure connection means. The requirements corresponding to a nominal fatigue pressure of 250 bars, as well as for 400 bars, have

  been respected, in accordance with the industrial standard

  trielle T 2 6 1-1974 of the National Fluid Power Asso-

ciation of the United Kingdom.

Claims (7)

  1 sealing means (1) for pressurized coupling members, characterized in that they comprise a first and a second surface   conical (6,9) formed, respectively, on a pre-   mier and on a second coupling member (10,11) and   extending around a central axis (20) of these   niers, these conical surfaces coming into contact with each other in an annular contact region (13) and the cone angle, measured relative to this axis, of the second conical surface being greater than the angle cone of the first conical surface,   and in that they also include an O-ring   that (2) coming into contact with the first and the   second coupling member in an immediate region-   axially adjacent to the region of   annular contact of conical surfaces.   2 The sealing means of claim 1, wherein the radial extent of said annular contact region between the first and the second conical surface is less than the radial extent   either of the conical surfaces.   3 The sealing means of one of the claims   1 and 2, in which the cone angle of the   second conical surface is from 1 to 100, preferably   rence of about 50, greater than the cone angle of the first conical surface.   4 The sealing means of one of the claims   previous tions, in which the first surface   conical at a cone angle of 15 to 200.   The sealing means of one of the claims   previous conditions, in which the region of con-   tact of the O-ring with the coupling members is offset upstream of the high pressure side of the annular contact region of the conical surfaces. 6 The sealing means of claim 5, wherein the O-ring is arranged in a   annular groove (3) formed in an outer surface   of the first coupling member, and the annular groove is located adjacent, in the axial direction,   to the conical surface of the first coupling member.   7 Pressure connection means, charac-   terrified in that they understand the means of   sheaity (1) for organs under pressure of one of the   claims 1 to 6, wherein the first and the   second coupling member (4,7) each comprise internal volumes (14,17) configured so as to form a passage of fluid passing through the connection means, and in which the first coupling member has a threaded external part (5) and the second coupling member has an internal threaded portion (8) homologous to allow a   connection by screwing of these members.   8 The pressure connection means of claim 7, wherein the outer part   threaded and the internal threaded part are available   located on the first and on the second coupling member   range with an axial offset from the first   and to the second conical surface, so that   stress these contacting surfaces when the   The coupling nes are connected by screwing.   9 The pressure connection means of one   claims 7 or 8, in which the offset   axial of the threaded and tapped parts is downstream of the   low pressure side of the annular contact region   between the conical surfaces. The use of connection means   pressure of one of claims 7 to 9 in a   high pressure fluid filtration system, in which the first coupling member comprises a filtering bell in the interior volume of which is provided a filtering element and in which the second coupling member comprises a filter head.