Pipe connection for conducting a pressurized fluid

Abstract

A pipe connection that includes two tubular connection pieces for a conical clamping connection, the connection pieces being screwed together by a union nut while one connection piece is plugged inside the other. Each connection piece has a conical sealing surface which sealingly rests against the other, and an annular groove is provided in one of the sealing surfaces. The union nut is slit on the collar side.

Claims

1. A pipe connection for conducting a pressurized fluid, comprising: two tubular connection pieces which are screwed together by a union nut in a conical clamping connection with one plugged into the other, wherein each connection piece has a conical sealing surface which bears in each case against the other of the two conical sealing surfaces, wherein the union nut comprises a tubular portion which at least partially has an internal thread for screwing the union nut on a first connection piece of the two tubular connection pieces, and a collar, arranged at one end of the tubular portion, for axially clamping a second connection piece of the two tubular connection pieces to the first connection piece, wherein the collar has a number of slits distributed around its circumference, and wherein the number of slits form an annular array of axially projecting clamping hooks, and an insulating tube arranged in an interior formed by the two tubular connection pieces and comprising a first end sealed against an inner surface of the first connection piece, a second end sealed against an inner surface of the second connection piece, and a flange abutting the inner surface of the first connection piece at a respective conical sealing surface of the first connection piece, wherein an outer surface of the insulating tube is spaced apart from the first connection piece and the second connection piece, forming a gap therebetween, the gap thermally isolating an interface of the two conical sealing surfaces from the insulating tube.

2. The pipe connection as claimed in claim 1, wherein in the union nut the number of slits have a slit length that is measurable in an axial direction and that the number of slits extend into the tubular portion.

3. The pipe connection as claimed in claim 1, wherein the union nut has an overall axial length and the slits extend as far as a middle of the overall axial length.

4. The pipe connection as claimed in claim 1, wherein the second connection piece comprises a flange, wherein the clamping hooks clamp on the flange to urge the conical sealing surfaces together.

5. The pipe connection as claimed in claim 4, wherein radially inner surfaces of the clamping hooks cooperate to form a first ramp, wherein the flange comprises a ramped outer surface configured to form a second ramp, wherein the first ramp and the second ramp cooperate so a radial clamping force exerted by the clamping hooks produces axial force that urges the conical sealing surfaces together.

6. The pipe connection as claimed in claim 4, further comprising a monolithic body comprising the second connection piece and the flange.

7. The pipe connection as claimed in claim 1, wherein one of the conical sealing surfaces comprises an outward conical sealing surface and the other of the conical sealing surfaces comprises an inward conical sealing surface, wherein the outward conical sealing surface comprises an annular groove recessed therein that is suitable for holding graphite therein and also for holding the graphite in a sealing manner against the inward conical sealing surface.

8. The pipe connection as claimed in claim 1, wherein the clamping hooks are configured to flex radially outward when the union nut is turned after the conical sealing surfaces seat on each other.

9. The pipe connection as claimed in claim 1, wherein an interference between the flange and the inner surface of the first connection piece prevents axial movement of the insulating tube.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and features of the invention are explained in more detail by way of an exemplary embodiment. In the drawing:

(2) FIG. 1 shows a perspective illustration of a pipe connection for conducting a pressurized fluid, having an axially partially slit union nut, and

(3) FIG. 2 shows the longitudinal section through the pipe connection having the union nut according to the invention according to FIG. 1.

(4) FIG. 3 shows an enlarged view of the circled area of FIG. 2.

DETAILED DESCRIPTION OF INVENTION

(5) In all of the figures, identical features are provided with the same reference signs.

(6) FIG. 1 shows a perspective illustration of a pipe connection 10 for conducting a pressurized fluid. The pipe connection 10 connects two tubular connection pieces 12, 14 releasably together. The pipe connection 10 has a union nut 15 as releasable element. In the exemplary embodiment shown, the union nut 15 is equipped with an external hex. At an axial end, the union nut 15 has a collar 20 typical therefor. Compared with conventional union nuts, the union nut 15 according to the invention has slits 23 which subdivide at least the collar 20, but advantageously also a part of the collarless axial portion of the union nut 15 into clamping hooks 25 in a segment-like manner. In the exemplary embodiment shown, provision is made of a total of twelve clamping hooks 25 and thus twelve slits 23, of which in each case six slits 23 are arranged at the corners of the hex and in each case six slits 23 are arranged at the planar surfaces arranged in between. The slits 23 do not in this case extend along the entire axial length A (FIG. 2) of the union nut 15, but only approximately half way from the collar-side end. Depending on the requirements, a smaller or greater number of clamping hooks 25 and slits 23 can also be provided.

(7) FIG. 2 shows a longitudinal section through the pipe connection 10 for conducting a pressurized fluid. The tubular connection pieces 12, 14, which are configured for a conical clamping connection 16, extend along an axis of symmetry 28 of the pipe connection 18. The second connection piece 14 to this end has a cone 18 having an outwardly directed conical sealing surface 21. At an inclination corresponding to the sealing surface 21, the first connection piece 12 has a likewise conical sealing surface 22, as part of a cone 24. The cone 24 forms the external cone and the cone 18 the internal cone of the conical clamping connection 16.

(8) Provided in the sealing surface 21 is an endlessly circumferential annular groove 26 for holding graphite (not shown in FIG. 2) as sealant. The two connection pieces 12, 14 are connected together with the aid of the union nut 15. Specifically, the union nut 15 has been screwed onto the first connection piece 12, wherein the union nut 15 presses, with its collar 20, a conical shaft flange 29, as rear part of the cone 18 of the second connection piece 14, in the direction of the first connection piece 12. The two connection pieces 12, 14 are configured in a tubular manner such that the fluid, for example a hydraulic oil or a gaseous or liquid fuel, can be transferred in the interior thereof.

(9) Specifically, the union nut 15 has an overall axial length which is designated A below. Within the meaning of this patent application, the union nut 15 can theoretically be subdivided into a tubular portion B, which is adjoined by the collar portion D. In the collar portion D, the inside diameter of the union nut 15 is reduced, thereby resulting in the shoulder-shaped collar 20 by way of which the shaft flange 29 of the second tubular connection piece 14 can be clamped. The slits 23 that segment the collar 20 have an axial slit length C starting from the collar-side end, wherein, in the exemplary embodiment shown, the axial slit length C has been selected such that the slits 23 extend into the tubular portion B of the union nut 15. This results in a screw-connection portion E which is adjoined monolithically by the in principle L-shaped clamping hooks 25. Depending on the selected tightening torque of the union nut 15, it is possible, on account of the slits, for the clamping hooks 19 to be pushed slightly outwards on account of the conical shaft flange 29, with the result that elastic pretensioning can be introduced into the pipe connection 10. Outwardly pushed, that is to say slightly fanned clamping hooks 25 are not illustrated in FIG. 2.

(10) The L-shaped design 27 of the clamping hooks 25 is schematically indicated in the lower part of the sectional illustration of the union nut 15 by way of dotted lines.

(11) Arranged in the interior of the pipe connection 10 is a thermally insulating tube 30. The thermally insulating tube 30 is arranged at least in that axial portion of the pipe connection 10 against which the internally located connection piecein this case the connection piece 14bears by way of its sealing surface 21 against the other sealing surface 22. However, according to the exemplary embodiment, the thermally insulating tube is axially extended in both directions, wherein the ends 32, 34 of the thermally insulating tube 30 bear as far as possible in a sealing manner against the internal surfaces of the connection pieces 12, 14, such that flowing of the fluid into an intermediate space 36 between the thermally insulating tube 30 and the internal surfaces of the connection pieces 12, 14 is avoided. In addition, a flange 38, which is fixed axially between the two connection pieces 12, 14, is provided on the external lateral surface of the thermally insulating tube 30.

(12) Instead of a thermally insulating tube 30, it is of course also possible to apply a thermally insulating layer to the internal surfaces of the pipe connection 10, which were previously in direct contact with the fluid to be conducted in the prior art, in order to retard the heat transfer between the pipe material or cone material and the fluid in the event of a change in the fluid temperature. This also contributes to improved leaktightness of the pipe connection 10 and to an increase in the breakaway torque of the union nut 15.

(13) FIG. 3 shows an enlarged view of the circled area of FIG. 2. Graphite can be seen disposed in the annular groove 26.