GB1559623A

GB1559623A - Coupling arrangement for fluid flow

Info

Publication number: GB1559623A
Application number: GB634777A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-02-16
Filing date: 1977-02-15
Publication date: 1980-01-23
Also published as: SE7601675L; DE2706323A1; BR7700916A; FR2341092A1; FR2341092B1; DE2706323C2; SE397401B

Description

(54) COUPLING ARRANGEMENT FOR FLUID FLOW (71) I'KJELL RONNY EKMAN, a Swedish subject, of Schanz 10, CH-6300 ZUG, Switzerland, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement :- This invention relates to a coupling arrangement providing for the flow of a fluid therethrough.

According to the present invention there is provided a coupling arrangement providing for the flow of a fluid therethrough and comprising a first member having a passageway therethrough and terminating in a female coupling part that has an internal cylindrical surface extending between two axially spaced recesses; and a second member having a passageway therethrough aligned with the passageway of the first member and the second member terminating in a male coupling part received within the female coupling part and having an outer cylindrical surface facing said inner cylindrical surface and spaced therefrom to provide a gap establishing communication between the two recesses, said external surface terminating at the outer end of the inner recess, with respect to the open end of the female part through which the male part is received, and having a first portion leading therefrom that has a surface inclined with respect to the axis of the aligned passageways and facing the inner recess to form therewith an annular space of increasing radial dimension away from said open end of the female part; a first resilient sealing ring located in said annular space and at least radially compressed therein and seated on and sealing said gap where it emerges at said outer end of the inner recess; and a second resilient sealing ring located in the outer recess to be slidable therein in the axial direction and being engaged by a second, facing, portion of the male part so as to be radially compressed.

The coupling arrangement defined above is in its connected position. The coupling arrangement finds particular utility in circumstances where when the male part is inserted into the female to make the coupling a cushion of the fluid medium is trapped behind the first sealing ring as the ring is contacted by the first portion of the male part.

The trapped medium can flow through the gap between the parts where it displaces the second sealing ring axially outwardly from the inner end of the outer recess. The second sealing ring is previously pushed up to that inner end by the action of the male part being inserted therethrough. Thus in the connected position, the second sealing ring is spaced from the inner end of the outer recess and the medium can be accommodated in the space between the second sealing ring and the inner end of the outer recess, as well as the gap, to prevent undue pressure building up and resisting the final completion of the connection of the coupling members. Preferably the second sealing ring is spaced from both ends of the outer recess.

Preferably the internal width of the first sealing ring when not compressed is equal to the width of the first portion of the male part part-way along the inclined surface thereof such that upon insertion of the male part the inclined surface engages the first sealing ring before the junction of the first portion with the external cylindrical wall of the male part reaches the outer end of the inner recess. As this sealing contact is made the medium cushion is trapped and flows into the outer recess in the described manner as the final connection position is reached.

Preferably the first portion of the male part has a surface leading from the external cylindrical surface that is substantially a continuation beyond the emergent gap of the outer end surface of the inner recess to form a seat for the sealing ring. The continuation surface may be concave, such as a radius in cross-section, for a first sealing ring in the form of an 0-ring.

The invention and its practice will be further described with reference to the accompanying drawings, in which: Figure 1 is a vertical cross-section of a coupling arrangement having male and female parts in a final connected position; Figure 2 shows to an enlarged scale a portion of the parts shown in Figure I in progressive stages of insertion of the male into the female part; Figure 3 shows to an enlarged scale a detail of the vertical cross-section of Figure I; Figure 4 shows to an enlarged scale another portion of the parts shown in Figure I as the final connected position is approached; and Figure 5 is a vertical cross-section of a detail of a modified embodiment of the female part shown in Figure 1.

In the figures, like elements of the coupling arrangement bear like reference numerals.

The coupling arrangement shown in Figure I has a first coupling member terminating in a female part I through which a fluid passageway 17 extends. A second coupling member 2 terminates in a male part 3 through which a passageway 18 extends that is aligned with the passageway 17 when the members are connected as illustrated.

The male part 3 is tubular and has a circular cylindrical outer wall which lies within and slightly spaced from a circular cylindrical inner wall 12 of the female part I to provide a gap 19.

The female and male parts are shown in a connected position which is referred to herein as the final connected position. In this connected position the coupling members are lockable to each other by means of not shown locking devices which can be of any known type, such as locking devices using locking balls or locking rings.

The male and female parts are sealed relative to one another by two axially-spaced sealing rings. The first, inner, sealing ring is numbered 10 and the second, outer, sealing ring 11. The sealing rings are conventional resilient 0-rings made in Nitril or Vitron (Registered Trade Mark), for example. The sealing rings are located in respective recesses formed in inner wall 12 of the female part 1.

The first ring recess for the first sealing ring is numbered 13 and cooperates with a shaped end portion of the male part 3 to provide an annular space in which the ring 10 is received.

The second recess 14 for the second sealing ring is adjacent the mouth or open end of the female part I.

The inner end (i. e. the end further from the open end of the female part) of the recess 13 is provided with an extended surface 15 leading to a reduced diameter portion of the female coupling member and which is opposite to the end surface 6 of the male part 3. The surfaces 6 and 15 face each other separated by a gap 16. Through this gap a fluid medium, being transferred through or static in the aligned passageways 17 and 18 acts on the first sealing ring.

The shaped end portion of the male part 3 inclues a sealing surface 4 inclined with respect to the axis of the aligned passageways 17 and 18 of the coupling arrangement so that the radial dimension of the annular space in which ring 10 is received increases away from the mouth of the female part. The inclined sealing surface is connected to the cylindrical envelope surface of the male part via a pronounced radius 5 and is connected to the end surface 6 of the male part via a chamfering 7. The junction or shoulder 21 (Figure 2) between the radius 5 and the cylindrical wall lies opposite the outer end (i. e. nearer the mouth of the female part) of the recess 13 and the radius forms a continuation of the end wall of the recess, split by gap 19, the combination providing a seat for the sealing ring 10 as will be further described below. The cylindrical portion 3 has its lower part enlarged beyond the outer recess 14. The facing portion of the female part is of correspondingly enlarged diameter.

The enlarged part extends through the mouth of the female part I and is cylindrical (circular) also. It is connected to the cylindrical portion 3 via a further radius 9 adjacent the outer end of the recess 14 so that the cylindrical outer wall of the male part defines with the recess 14 an annular space in which sealing ring I I is received.

In the shown final connected position of the male and female parts the first sealing ring 10 is radially compressed and to a certain extent also axially compressed so it effectively bridges the gap 19 and seals this gap from the gap 16. The seat bottom for the first sealing ring can be seen as formed by the intermediate surface at the radius 5, the lower part of the inclined sealing surface 4 and the outer end wall of the ring recess 13, the seat bottom being divided by the annular gap 19.

The axial length of the second recess 14 considerably exceeds the axial dimension of the second sealing ring lI even when the second sealing ring is radially compressed as shown. The sealing ring 11 is axially slidable in the recess as will be further described. At the upper or inner end wall, the second recess 14 is provided with a bevelled edge 20 leading to the cylindrical inner wall 12.

Figure 2 shows in more detail the disposition in the second recess 14 of the second sealing ring I I as the male part is inserted into the female. From an initial position of the sealing ring I 1 abutting the outer end wall of recess 14, as shown in full line I i, the second sealing ring is axially inwardly displaced in the second recess 14, by means of the male member 2 which interacts with the second sealing ring via its shoulder 21. The displacement of the second sealing ring continues until it comes in contact with the inner end wall 22 of the recess 14 at a position shown in dashed line and designated 111.

After that, the ring is to slide on the cylindrical outer surface of the male part under the continued insertion of the male part beyond the lower dashed-line position. The inner diameter of the ring 11 is less than the diameter of the cylindrical wall of male part 3 so that the sea'ing ring is radially compressed.

The bevelled edge 20 is intended to prevent damage to the second sealing ring as the ring slides on the male member.

After the shoulder 21 of the male part has passed the sealing ring 11 and the ring recess 14, continued insertion of the male part brings it up to the first sealing ring 10.

During this movement a cushion 23 of the medium will be created at the shoulder 21 owing to medium remaining on the opposite walls of the male and female members and ; or owing to the fact that valves (not shown) of the coupling arrangement begin to open the connection to connecting pipes (not shown) carrying the medium. The medium cushion can also comprise grease or other lubricant applied to the coupling members. In some cases, air can be intermixed in the cushion.

Thus, the medium cushion is pushed in front of the shoulder 21 and has at this stage a direction of movement indicated by arrow 24.

When the shoulder 21 is approaching the first sealing ring 10 the medium cushion is allowed to pass by the sealing ring 10 as long as the inclined sealing surface 4 of the end portion of the male part does not effect a sealing contact with the first sealing ring.

However, when the sealing contact occurs during the last stage of the connecting procedure the medium cushion will, as shown in Figure 4, be enclosed in a space below the first sealing ring. The bounding surfaces of this space are created by the lower part of the sealing surface 4, the radius 5 and an inner portion 25 of the inner wall 12 of the female part. The last mentioned portion has a length a. The space beneath ring 10 reduces as the final connection position is reached and the connecting force F on the coupling members forces the medium cushion downwards in the gap 19 and in the direction of arrow 26, i. e. in the direction of the second ring recess 14 as evident from Figure 3, in which the medium direction is also indicated with 26.

The second sealing ring, now compressed by the male part 3, occupies the position shown by 111 as long as the medium passes by the first sealing ring 10. When the connecting force on the coupling members presses the medium cushion downwards (towards the mouth of the female part), the second sealing ring is displaced backwards (outwardly) by the medium cushion entering the second recess 14 and the medium partially fills it as the displacement of the second sealing ring takes place. The second recess 14 is able to accommodate the whole medium cushion apart from that medium remaining in the gap 19 between the male and female parts. In this way undue build up of pressure of the trapped medium is prevented so enabling a relatively small connecting force to be used.

In order to obtain the axial displacements of the second sealing ring in the second ring recess 14 and sliding on the cylindrical portion 3 of the male member, it is important to provide the second ring recess with a depth d (Figure 2) in the radial direction which is such that the distance b between the bottom 27 of the second ring recess and the facing cylindrical surface of the male member is less than the thickness c in the radial direction of the cross-section of the second sealing ring when not compressed. This non-compressed condition is that seen in Figure 2. Thus, the distance b, which is the radial thickness of the ring 11 under compression, should be less than the non-compressed thickness c by an amount, given in per cent, within the range 4-25%. The limiting values of the range are included. An amount of compression of between 8 and 16% is preferred. As an example of the illustrated embodiment the diameter of the cylindrical portion 3 of the male member is 12-0 mm. The diameter of the bottom surface 27 of the ring recess is 16-6 mm. which gives a gap b of 2-3 mm. The second sealing ring is made of a material such as Nitril or Viton (Registered Trade Mark) and has an inner diameter of il-91 mm and a cross-section thickness (= the non-compressed thickness c) of 2-62 mm, which means that the distance b is less than the thickness c by 12 2%. The Shore-number of the second sealing ring is chosen to be 70. The diameter of the facing cylindrical surfaces of the male and female parts are chosen to provide a gap 19 in the range 0-025 to 0 1 mm including tolerances. The gap 19 may haveavalue within the range 0-01 to 0-3 mm, in which range the aforementioned range 0-025 to 0-1 mm is preferred. The angle of inclination a (Figure 4) of the sealing surface 4 to the axis has a value of 20 and a suitable range for its is 5 to 20 . The distance a (Figure 4) is about 0-5 mm, but values between 0-2 and 2-7 mm are suitable. The second sealing ring extends outside the second ring recess about 1/4 of its thickness in non-compressed condition. In this condition the outer diameter of the second sealing ring 14 can in the general case either be substantially equal to that of the bottom 27 of the second recess 14, or can be in excess of the latter so as to be constricted in the second recess; for example, having an outer diameter which exceeds the diameter of the recess bottom 27 by 0-1 to 0-4 mm.

The first sealing ring is also made of a material such as Nitrile or Viton (Registered Trade Mark), and has the Shore-number of 70. The first sealing ring is adapted to make sealing contact with the inclined surface 4 (Figure 4) as the male part is inserted at the given value or within the given value range of a. The cross-section and the inner diameter of the first sealing ring 10 is chosen with regard to the dimensions of the shaped portion of the male part and, in the embodiment being exemplified, has an inner diameter of 9-92 mm and a cross-section thickness of 2-62 mm.

In the non-compressed condition, the first sealing ring has a radius which substantially corresponds to the radial depth of the first recess 13.

As regards the volume of the second recess 14, this is dependent on the volume of the medium cushion trapped below the first sealing ring (apart from the medium in the gap). It is then important that the trapped medium cushion is allowed to fill the volume of the recess 14 remaining when the volume of the second sealing ring is excluded up to only 90% of this remaining volume at most.

A filling of 50-70% of the remaining volume is preferred. However, the maximum filling percentage is shown in Figure 3 where it will be noted the ring 11 is spaced from both ends of the recess 14 and that the space at the outer end is vented by the gap between the end of the female part and the adjacent surfaces of the male part. As an example of the axial dimension of the second ring recess beyond the length of the compressed second sealing ring 11, 0-3 to 2-7 mm can be mentioned. In such a way the connection of the male and female parts with small connecting forces can be realised due to the accommodation of the medium cushion in the outer recess 14.

The coupling arrangement described above is intended to be used in connection with hydraulic oil, but it is also useful with other fluids such as air or the like. For a high viscosity fluid, the passage of the trapped medium cushion to the second ring recess may be improved by means of one or more grooves located on the inner wall 12 of the female part I, the grooves extending at least partially axially. Such an embodiment is shown in Figure 5 in which a helicoidal groove is used. However, the helicoidal groove can be substituted by one or more vertical arranged grooves on the inner wall.

The groove size is chosen in dependence of the viscosity of the fluid with which the coupling arrangement is to be used.

By the above described structure the connecting force symbolized by arrow F in Figure 4 can be maintained relatively small through- out the connecting procedure.

Claims

WHAT WE CLAIM IS :- I. A coupling arrangement providing for the flow of a fluid therethrough and comprising a first member having a passageway therethrough and terminating in a female coupling part that has an internal cylindrical surface extending between two axially spaced recesses; and a second member having a passageway therethrough aligned with the passageway of the first member and the second member terminating in a male coupling part received within the female coupling part and having an outer cylindrical surface facing said inner cylindrical surface and spaced therefrom to provide a gap establishing communication between the two recesses, said external surface terminating at the outer end of the inner recess, with respect to the open end of the female part through which the male part is received, and having a first portion leading therefrom that has a surface inclined with respect to the axis of the aligned passageways and facing the inner recess to form therewith an annular space of increasing radial dimension away from said open end of the female part; a first resilient sealing ring located in said annular space and at least radially compressed therein and seated on and sealing said gap where it emerges at said outer end of the inner recess; and a second resilient sealing ring located in the outer recess to be slidable therein in the axial direction and being engaged by a second, facing, portion of the male part so as to be radially compressed.
2. A coupling arrangement as claimed in Claim 1 in which said second sealing ring is at least spaced from the inner end of the outer recess at which said gap emerges.
3. A coupling arrangement as claimed in Claim 2 in which said second sealing ring is spaced from the outer end of the outer recess.
4. A coupling arrangement as claimed in Claim 3 in which the volume of space between the second sealing ring and the inner end of the outer recess is not more than 90% of the volume of the total space between the ends of the outer recess not occupied by the second sealing ring.
5. A coupling arrangement as claimed in Claim 4 in which the volume of the space between the second sealing ring and the inner end of the outer recess is in the range of 50 to 70% of the volume of the total space between the ends of the outer recess not occupied by the second sealing ring.
6. A coupling arrangement as claimed in any preceding claim in which the portion of the male part engaged by the second sealing ring is a continuation of said external cylindrical surface.
7. A coupling arrangement as claimed in any preceding claim, in which said first portion of the male part has a surface leading from said external cylindrical surface to said inclined surface that is substantially a continuation beyond said emergent gap of the outer end surface of said inner recess to form a seat for the first sealing ring.
8. A coupling arrangement as claimed in Claim 7 in which said continuation surface is concave and the first sealing ring is an 0-ring.
9. A coupling arrangement as claimed in any preceding claim in which the internal width of the first sealing ring when not com pressed is equal to the width of said first portion part-way along said inclined surface such that upon insertion of the male part the inclined surface engages the first sealing ring before the junction of said first portion with said external cylindrical wall reaches the outer end of the inner recess.
10. A coupling arrangement as claimed in any preceding claim in which said first portion leads to a transverse annular end wall of the male part that faces and is spaced from a radially inward continuation of the inner end surface of the inner recess.
11. A coupling arrangement as claimed in any preceding claim in which said gap is between 0-01 and 0-3 mm and the second sealing ring is radially compressed by an amount in the range of 4 to 25% of the radial dimension thereof when not compressed.
12. A coupling arrangement as claimed in Claim 11 in which said amount of compression is in the range of 8 to 16%.
13. A coupling arrangement as claimed in any preceding claim in which the external cylindrical wall of said female part has one or more grooves therein that are directed at least partially axially.
14. A coupling arrangement as claimed in Claim 13 wherein the or each groove is helicoidal.
15. A coupling arrangement substantially as hereinbefore described with reference to Figures I to 4 or to Figures 1 to 4 as modified by Figure 5 of the accompanying drawings.