Joint system between fittings and pipes

Abstract

In a press-fit joint system for tight connection between a pocket provided at an open end of a fitting or valve and an open end of a pipe, the pocket of the fitting or valve slidably accommodates the pipe and has an annular seat projecting outwardly that accommodates a compressible ring seal, wherein the connection is formed by imparting a plastic deformation to the a pair formed by the pocket and the pipe, and compressing the ring seal, wherein the ring seal has one or more channels with an upstream opening and a downstream opening such as to allow a passage of fluid from an inside of the system to an outside prior to proper pressing between the pipe and the fitting or valve and to occlude and to prevent the passage of fluid upon application of proper pressing between pipe and fitting or valve.

Claims

1. A press-fit joint system for tight connection between a pocket provided at an open end of a fitting or valve and an open end of a pipe in a hydraulic or pneumatic system, the press-fit joint system comprising: the fitting or valve, the pocket of said fitting or valve being configured to slidably accommodate the pipe to which it the pocket is to be connected and having an annular seat projecting outwardly that accommodates a compressible ring seal, wherein the connection of the pocket and the pipe is formed by imparting a plastic deformation to a pair formed by the pocket and the pipe, and at the same time compressing the ring seal so as to be pressed against surfaces of the pipe and the pocket, and the compressible ring seal, wherein said ring seal has one or more channels having an upstream opening and a downstream opening such as to allow a passage of fluid from an inside of the press-fit joint system to an outside prior to proper pressing between the pipe and the fitting or valve, and to occlude and to prevent the passage of fluid upon application of proper pressing between pipe and fitting or valve; said one or more channels having a curvilinear fluid path along the thickness of the ring seal between said upstream opening and said downstream opening.

2. The joint system of claim 1, wherein a cross-section of the ring seal is circular.

3. The joint system according to claim 2, wherein said ring seal comprises three channels arranged radially at angles of 120 from a center.

4. The joint system according to claim 1, wherein a cross-section of the ring seal has a non-circular shape, having a predominantly flat lower section configured to be applied at an outer surface of the pipe and a curvilinear upper section configured to be applied at the annular seat of the pocket.

5. The joint system according to claim 1, wherein said one or more channels are obtained in an area of the ring seal, with reference to a vertical section of the ring seal, which is to be positioned closer to the surface of the pipe than to the annular seat.

6. The joint system according to claim 1, wherein sections of the upstream and downstream openings of said one or more channels are of circular shape.

7. The joint system according to claim 1, wherein sections of the upstream and downstream openings of said one or more channels are non-circular in shape consisting of one of elliptical, rhomboidal and spindle-shaped.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features of the invention will become clearer from the detailed description that follows, referring to a purely illustrative and therefore non-limiting embodiment thereof, illustrated in the accompanying drawings, wherein:

(2) FIG. 1 is a sectional view of a press-fit type joint system having a ring seal according to the prior art, in uncompressed condition;

(3) FIG. 2 is a perspective sectional view of a press-fit type joint system having a ring seal according to the present invention, in uncompressed condition;

(4) FIG. 3 is a view like that of FIG. 2 in planar section;

(5) FIG. 3a is an enlargement of the view of FIG. 3 at the ring seal;

(6) FIG. 4 is a sectional view of a press-fit type joint system showing a second embodiment of a seal ring according to the present invention, in uncompressed condition;

(7) FIG. 4a is an enlargement of the view of FIG. 4 at the ring seal;

(8) FIG. 5 is a sectional view of a press-fit type joint system showing a third embodiment of a ring seal according to the present invention, in uncompressed condition;

(9) FIG. 5a is an enlargement of the view of FIG. 5 at the ring seal;

(10) FIG. 6 is a front view of a seal ring according to the present invention;

(11) FIG. 6a is a sectional view taken along line F-F of FIG. 6;

(12) FIG. 6b is an enlarged view of detail A in FIG. 6a; and

(13) FIG. 7 schematically shows three exemplary sections of channels of non-circular shape.

DETAILED DESCRIPTION OF THE INVENTION

(14) Preferred embodiments of joint systems by means of press-fit connection according to the present invention will now be described in detail with reference to the accompanying drawings.

(15) The solution according to the invention envisages making special by-pass channels to allow the leakage of fluid to the outside before pressing, avoiding unwanted engagement phenomena from occurring during final testing.

(16) FIGS. 2 and 3 show, in a conventional manner, sectional views of a press-fit type joint between a fitting or valve 111 and a pipe 112, which is slidably accommodated in a pocket 113 obtained at one end of the fitting 111. The fitting or valve 111 has an annular seat 115 projecting outwardly which is intended to accommodate a rubber ring seal (O-ring) 100 according to the invention. The views show the configuration of the joint before the components are pressed together and the ring seal is deformed by means of appropriate pressing tools.

(17) FIG. 3a shows a detail of an embodiment according to the invention, showing a section of a seal 100 with a channel or duct 103 having upstream opening 105 and a downstream opening 107 to allow a flow of fluid even when the seal is pushed into contact with the inner walls of the annular seat 105 and of the pipe 112 in the vicinity of the peripheries 108 and 109 by the test pressure of the system without there having been an effective and complete compression of the terminals. Upon application of a suitable joint pressure, the joint portions will plastically deform in turn compressing the seal 100 causing at the same time the occlusion of the channels 103 of the ring seal 100, thereby rendering the joint fluid tight.

(18) The channels 103 may be provided in different number and shape on the seal 100. In the embodiment of FIG. 3a a channel 103 is shown with a straight development between the upstream opening 105 and the downstream opening 107, which thus presents itself in the form of a longitudinal cylindrical channel that is obtained through the thickness of the ring 100 in a direction substantially parallel to the axis of the pipe 112. FIG. 6 shows a particular embodiment of the ring seal 100 formed by three longitudinal channels 103 obtained in the thickness thereof.

(19) FIG. 6 is a front view of a ring 100 with three channels 103 arranged radially at angles of 120 from the center on an intermediate circumference 110 between the peripheries 108 and 109 of the ring. FIG. 6a is a section taken along line F-F of FIG. 6, while FIG. 6b is an enlargement of detail A of FIG. 6a. This configuration turned out to be advantageous to uniformly cover the various points of the seal and ensure a balance of the leakages by optimizing the possibilities of having safe and open by-pass channels before pressing without an excessive number of them, thus also optimizing their occlusion as a result of pressing the joint.

(20) The invention thus provides for allowing the leakage of fluid to the outside before pressing by means of by-pass channels 103 in which the upstream 105 and downstream 107 openings of the channels are positioned inside the vertical section (with reference to FIG. 6) of the seal 100 and not at its peripheral points 108 and 109.

(21) In doing so, all the macroscopic defects described above continue to be positioned at the points 108 and 109, and are now irrelevant for the proper functioning of the bypass channels 103.

(22) The one shown in FIGS. 6, 6a and 6b is only one of the preferred embodiments, it being understood that the channels provided on the seal rings depending on the applications and system requirements can vary in number, section, trajectory and positioning along the section of the rubber seal, always remaining positioned inside the section (also not necessarily of circular shape) and not in its peripheral points 108 and 109.

(23) Compared to the known solutions, in fact, the ring seals can have channels 103 positioned so as to be much further away from the walls of the seat 115 of the seal and from the pipe 112 and, considering their great efficiency in allowing the by-pass flow derived from their structure, they can be made with very small flow sections. This directly entails both the minimization of the size of the possible defects (any burrs near the upstream 105 and downstream 107 openings of the channels, any deviations in the trajectory of the channels) and the minimization of the variety of types of the same defects, as well as their possible synergistic action.

(24) FIGS. 4 and 4a show a joint with a ring seal 100 provided with a channel 103 extending with a curvilinear trajectory along the thickness of the ring between an upstream opening 105 and a downstream opening 107 to optimize the interaction with the walls of the seat 115 of the seal.

(25) FIGS. 5 and 5a instead show a ring seal 100 with a non-circular shaped cross-section, with a predominantly flat lower zone and a curvilinear upper zone, so as to better conform to the annular seat 115. In such a configuration, the channels 103 are arranged so as to be closer to the outer diameter of the pipe 112 than to the surface of the annular seat 115, optimizing the by-pass flow through the channels 103 prior to pressing and the occlusion efficacy thereof following pressing.

(26) As anticipated, such configurations are not limiting, and a ring seal could have a variable number of channels arranged with different trajectories and positions with respect to the median plane, as needed, to optimize the leakage effect before pressing and the sealing effect after compression.

(27) Finally, it should be noted that the sections of the upstream 105 and downstream 107 openings can also be of various types, and not necessarily circular. FIG. 7 shows, for example, a) elliptical, b) rhomboidal and c) spindle-shaped sections that could always optimize sealing after pressing.

(28) The present invention is not limited to the particular embodiments previously described and illustrated in the accompanying drawings, but numerous modifications can be made to it in detail, within the reach of the person skilled in the art, without thereby departing from the scope of the invention itself, as defined in the appended claims.