WO1996035072A1

WO1996035072A1 - Fast operated pipe coupling

Info

Publication number: WO1996035072A1
Application number: PCT/NO1996/000106
Authority: WO
Inventors: Heyn Halfdan Magnus; Olaf Bjarne Feste
Original assignee: Kongsberg Offshore A.S
Priority date: 1995-05-02
Filing date: 1996-04-30
Publication date: 1996-11-07
Also published as: NO951697L; NO951697D0

Abstract

A rapid coupling for pipes with a cylindrical male member (1) and a female member (2), wherein a first (2) of these members carries an annular packing (4) which after connection of the members (1, 2) abuts sealingly against a sealing surface (8) of the second member (1) along its entire circumference. The second member (1) has at least one axially extending groove (7), which extends from the second member's free end (6) to near the sealing surface (8).

Description

Fast operated pipe coupling

The invention concerns a rapid coupling according to the introduction to claim 1.

In US 5 232 021 there is disclosed a rapid coupling of the above-mentioned type wherein the second part is composed of the male member and its diameter at its free end is reduced in relation to the diameter of the sealing surfaces over an axial distance which extends from this member's free end approximately to the sealing surfaces. Each of the members comprises valves which are opened when the members are connected and closed when they are disconnected.

When the members are uncoupled, or more precisely when the coupling members are withdrawn from each other while the packing is still in abutment against the sealing surface and after the valves have been closed, the pressure of the fluid in the space between the members can be reduced to below the ambient pressure after the valves have been closed.

When the members continue to be withdrawn from each other, therefore, a differential pressure can occur over the entire packing, along its circumference, which pressure attempts to pull the packing out of the annular groove in which it is inserted and into the space between the members, when the section with reduced diameter comes into communication with this annular groove, with the result that the packing may have to be repositioned before the members can be coupled together.

This may happen particularly when the coupling is employed at great depths in the ocean, since the differential pressure can then be very great.

Conversely, attempts can be made to force the packing out of the groove the other way considered in the axial direction and out of the female member and it may be squeezed between the members when they are coupled together, which is also disadvantageous.

In order to counteract this extrusion and squeezing the packing can be made of a relatively rigid material, which is a disadvantage, since its sealing properties are then reduced. The object of the invention is to provide a rapid coupling which is not encumbered by the above-mentioned disadvantages.

The characteristics of the rapid coupling according to the invention are pres¬ ented by the characteristic features indicated in the claims.

The invention will now be described in more detail with reference to the drawing which illustrates schematically a rapid coupling according to the invention.

Fig. 1 illustrates a longitudinal section through a male member and a female member of a first embodiment of a rapid coupling according to the invention, these components being withdrawn from each other and sections cut away.

Fig. 2 illustrates a longitudinal section through the first embodiment of the rapid coupling according to the invention, its male member and female member being coupled together.

Fig. 3 illustrates a longitudinal section through a male member and a female member of a second embodiment of the invention, these components being withdrawn from each other and sections cut away.

Fig. 4 illustrates a longitudinal section through the second embodiment of the rapid coupling according to the invention, its components being coupled together.

Normally rapid couplings of this type comprise devices for mechanically securing the coupling members to each other and valves which are opened and closed automatically by a connection or disconnection of the members. Such devices, however, have been omitted from the drawing in order to improve the clarity of the drawing.

As illustrated in fig. 1 a first embodiment of a rapid coupling according to the invention comprises a male member 1 which can be inserted into and coupled to a female member 2.

The female member 2 has a cylindrical bore 3. In the bore there is provided a circular groove in which there is inserted an annular packing 4. The male member is in the form of a tubular pin which is circular in cross section with a bore 5. From the free end of the male member 1, i.e. the end 6 of the male member 1 which faces the female member 2 immediately before being coupled thereto, there extends an axially extending groove 7 to near a sealing surface section 8, hereinafter called a sealing section, of the circular external surface of the male member 1.

When the male member 1 has to be coupled to the female member 2. its free end is inserted into the bore 3 of the female member 2. As insertion continues fluid which is enclosed in the space between these components, will be able to escape via the groove 7 until the male member's sealing section 8 comes into contact with the packing 4, as shown in fig. 2, with the result that this space no longer communicates with the area outside the rapid coupling. Due to this escape of fluid during the connection no differential pressure exists over the packing 4. Thus there is no risk of the packing being forced out of its annular groove in the bore 3 of the female member, and of the packing being squeezed between the male member and the female member.

When the male member 1 has to be uncoupled from the female member 2 and has been withdrawn a short distance from it, the space between the coupling members is brought into communication via the axial groove 7 with the area outside the coupling members 1,2, thus enabling any differential pressure over the packing to be equalized. This is particularly important if the rapid coupling is located at a great depth in the ocean where the pressure outside the coupling is great, while a pressure in the space between the coupling members 1.2 may be below one atmosphere. Thus as the male member 1 continues to be withdrawn from the female member 2, there is no danger of the packing being pulled out of its annular groove and away from the female member 2.

Fig. 3 illustrates a second embodiment of the rapid coupling according to the invention. This comprises a cylindrical, tubular male member 11 and a female member 12.

In the external cylindrical surface of the male member 11 there is provided a circumferential groove in which there is inserted an annular packing 14. The female member has a bore 13. From the end 16 of the female member 12 which faces the male member 11 immediately before these components are connected, to near a sealing surface section 18 of the bore 13, there extends an axially extending groove 17.

When the male member 11 has to be coupled to the female member 12, its end is inserted in the bore 13. As the male member 11 continues to be inserted into the female member 12, fluid which is located in the space between the coupling members can escape via the axial groove 17, with the result that there is no danger of the packing being forced out of its annular groove. After the male member has been inserted so far into the female member that the packing has passed the internal end of the axial groove 17 and comes into contact with the sealing surface 18, the packing 14 provides a seal between the coupling members.

When the male member 11 and the female member 12 are uncoupled from each other, the male member 11 is first moved such a distance that the space between the coupling members comes into communication with the area outside the coupling via the axial groove 17. Any differential pressure over the packing as a result of a reduction in the pressure of the fluid in the space between the coupling members is thereby equalized, with the result that there is no danger of the packing being pressed into the space between the coupling members and possibly being lost when the male member is completely removed from the female member.

Due to the fact that the axial groove 7, 17 has a relatively small dimension in the circumferential direction of the cylindrical, external surface of the male member 1 and the bore of the female member 12, only a small section of the packing will be liable to be pulled away from the circular groove, while the remaining section of the packing remains therein. The packing can therefore be made of a relatively soft material with good sealing properties.

It will be understood that several axial grooves 7,17 can be provided, since the intermediate section of the annular groove for the packing 4,14 will provide a sufficiently good support for the packing to prevent it from being moved out of its annular groove.

Claims

PATENT CLAIM

1. A rapid coupling for pipes comprising a pin-shaped, cylindrical male member (1;11) and a thereto adapted female member (2;12), wherein a first (2;11) of these members carries an annular packing (4:14) which after connection of the members (1,2;11,12) abuts sealingly against a sealing surface (8; 18) of the second member (1;12) along its entire circumference, characterized in that the second member (1;12) has at least one, axially extending groove (7; 17), which extends from the second member's free end (6; 16), i.e. the end which immediately before connection faces the first member, to near the sealing surface (8; 18).