GB2152169A

GB2152169A - Pipe coupling

Info

Publication number: GB2152169A
Application number: GB08429423A
Authority: GB
Inventors: Umberto Fracchia
Original assignee: Renza Bosco
Current assignee: Renza Bosco
Priority date: 1983-11-22
Filing date: 1984-11-21
Publication date: 1985-07-31
Also published as: ATA367084A; ES8507251A1; GB8429423D0; DK552384A; IT8323825A0; DK552384D0; FR2555285A1; DE3442424C2; FR2555285B1; IT1169132B; ES537780A0; DE3442424A1; AT390133B

Abstract

A connecting union for pipes, taps, valves, hydraulic equipment capable of compensating for assembly errors in concentricity and connection distance, has a connecting body 4 with a part-spherical surface 4a that may be tightened up against an opening 5 of another component 1 by means of a ring nut 6, the union also having, at its other end, a threaded portion 10 with a reusable sealing ring 12. <IMAGE>

Description

SPECIFICATION Improvements in or relating to connecting unions for pipes and the like This invention relates to connecting unions for pipes and the like.

In order to connect together pipes, taps, valves, hydraulic equipment and the like, threaded connecting units are usually used which facilitate sealed tightening without the need, when screwing, to rotate the entire pipe or piece of equipment. This applies for instance, to the case of radiator valves in heating systems, where pipes are connected to radiators which are fixed in position. Assembly of such pipes and equipment is very often subject to errors and imperfections in manufacture which are difficult to avoid and, in particular, the concentricity of the joints and exact connection distance are rarely guaranteed. This therefore requires adjustments to be made during assembly that may produce distortion of the pipes or cause overstressing and in any case involve additional assembly time.

Furthermore, the seal for the circulating fluid around the threaded joints is usually made by hemp fibres covered in lubricating paste or by strips of plastics material, wound around the threaded parts and remaining inserted between the parts in contact.

Plastics coverings have also been proposed to cover all the joint's surfaces by means of films applied to these parts using various processes, which form a continuous thickness both on the parts being joined and on all the rest of the joint, the film being trapped between the parts in contact and such that it fills the gaps between the parts and provides a pressure tight seal.

These known systems, although satisfactory as regards the seal, have various drawbacks which consist both in the need for skilled labour when hemp combined in various ways with other products is used, with a considerable waste of time and no possibility of reuse when the joint is dismantled, and in the cost of production when continuous plastics films are applied over the entire joint, films which apart from being unnecessary and on occasion damaging on those parts which are not in contact, are completely ruined when the joint is dismantled, particularly in the threaded part, thus preventing the joint from being reused and necessitating replacement of the whole piece.

According to the present invention there is provided a connecting union for pipes and the like the union incorporating means to compensate for assembly errors and comprising two parts, of which a first part is a tubular connecting body and the second part is a component for joining to the connecting body, one of said parts having at one end a portion having a part-spherical surface capable of forming a sealed coupling with a complementary shaped opening of the other part, said portion being arranged to be pressed against the complementary surface of said opening by a threaded ring nut on one of the parts which can be screwed onto a threaded end of the other part.

The other part can be an independent connecting element having at its opposite end to the complementary surface means for forming a connection and seal with a pipe, hydraulic equipment and the like, or else the other part can be part of or connected to a valve, tap, piece of hydraulic equipment or the like.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is an overall view, partly in section, of one form of a connecting union for coupling a valve to a radiator, Figure 2 is a view, partly in section, illustrating an angular oscillation that can be achieved by the connecting union shown in Figure 1, Figure 3 is a plan view showing a detail of the sealed connection of the connecting union to a radiator, Figure 4 is a view similar to Figure 1 of a second form of connecting union in a closedup condition, and Figure 5 is a view of the connecting unit shown in Figure 4 in a fully extended position.

Figure 1 shows a part in the form of a valve body 1 which is basically of a known type and has a threaded connecting piece 2 for connection, for instance, to a feed pipe.

Connection to a piece of user equipment, such as a radiator for example, is achieved by means of a part in the form of a tubular connecting union 3. This union comprises a connecting body 4, which couples with an opening in the form of a threaded outlet 5 of the valve 1, and a threaded ring nut 6, which is tightened onto the thread of the outlet 5.

The connecting body 4 has a leading portion 4a with a part-spherical surface, which forms a seal with a complementary profiled sealing ring 7 when tightened thereagainst.

the tightening being achieved through a frustoconical surface 8a of a raised collar 8 of the ring nut 6 pressing on a rearward part of the portion 4a as the ring nut is tightened. The sealing ring 7 can be of a synthetic deformable material that is capable of withstanding the foreseen conditions of use.

The part-spherical portion 4a of the connecting body 4 is joined to the cylindrical portion 4b by means of a portion with a smaller cross-section forming an encircling groove 9. In this manner, as shown in Figure 2, it is possible to compensate for an angular misalignment between centreline of the outlet 5 of the valve 1 and the tube or piece of equipment connected to the valve up to an angle a, equivalent to about 6 , the connecting body 4 being able to rotate about the centre of the part-spherical portion 4b.

Figure 2 shows the connecting body 4 in the central position and, as indicated by finer lines, in the two extreme positions of angular misalignment, referred to as 4' and 4" respectively. The seal is ensured, over the entire field of possible angular misalignment, by the complementary curved surfaces of the front portion 4a of the connecting body 4 and the sealing ring 7 on the outlet 5.

The end of the body 4 remote from the portion 4a has a threaded section 10 for connection to a piece of equipment, such as a radiator 11 illustrated in Figure 3.

Between the groove 9 and the threaded section 10, cut along a limited length of the body 4, is a packing ring 12 inserted in another groove forming a seat 13 around the body 4 for the packing ring.

The packing 12 has a slightly smaller outer diameter than the crest diameter of the threaded section 10 in the area adjacent to the threaded section 10 (up to half a thread for example) and gradually increases in its diameter towards the middle cylindrical portion 4b of the body 4, being substantially greater than the diameter of the threaded section 10 at its end furthest therefrom.

In this manner, as can be seen in Figure 3, when coupling with a piece of equipment, such as the radiator 11. an inner thread 14 of the connection aperture of the radiator 11 interferes with the surface of the packing 12, causing it to deform and to fill completely the grooves of the thread, as well as compressing the end portion of the packing 12 against a side 15 of the seat 13, thereby forming an effective seal.

The diameter of the cylindrical portion 4b of the body 4 is greater than the diameter of the threaded section 10, so that the side 15 is sufficiently wide to provide an effective support for the packing 12 even when the latter is deformed and made to slide as the threaded section is being tightened, in order to ensure the best possible seal. As can be seen in Figure 3, the seat 13 of the packing 12 has a knurled or similar part 1 3a in order to prevent the packing 12 from rotating during screwing.

Figures 4 and 5 show a different embodiment which also provides for the possibility of achieving, in addition to compensation for angular misalignment, also compensation for errors of longitudinal distancing between the pipe and equipment to be connected by providing means to vary the linear extent of the union.

For this purpose, the connecting body 4 comprises an element 16 which has a cylindrical portion 17 on which can slide a partspherical body 18, made in two parts 1 8a and 1 8b The part 1 8a has an internal shoulder forming a seat for a sealing ring 19 and the part 1 8b is really a ring which is provided with an oblique split 20.

Figure 5 shows the maximum possible longitudinal travel of the connecting body, which is achieved by means of relative sliding between the body 18 and the cylindrical portion 17.

At its leading end, the cylindrical portion 17 has a counterbore or outwardly flared part 21, made after the part-spherical body 18 is assembled thereon, which, together with an internal rib 22 on the body 18, serves to guide the relative sliding between the body 18 and portion 17.

As the ring nut 8 is tightened onto the threaded outlet 5, the part-spherical body 18 is forced against the sealing ring 7 and in addition the radial action exerted by the frustoconical surface 8a of the ring nut 8 against the split ring 1 8b determines to what extent it is tightened against the cylindrical portion 17, thus stopping by friction relative longitudinal sliding movement between the body 18 and the body 16; thereby holding these parts in the desired position.

The part-spherical surface of the body 18 also enables compensation for angular misalignment, similar to the previously-described embodiment.

The tightening of the connecting body 4 shown in Figure 1 to the equipment to which it is to be connected is facilitated by an inner hexagonal surface 23 made in the bore of the body 4, this being done before the valve 1 is fitted. The element 16 of the second embodiment, presenting no problems in assembling the ring nut 8, has an outer hexagonal portion 24 adjacent to the packing 12. The packing 12 is able to be pressed against a side 25 of its seat, which constitutes a beat surface.

The connecting body 4, in both embodiments, can also be used on conventional valves which do not provide for the sealing ring 7 but do have a frustoconical coupling surface, against which the part-spherical portion 4a (or 18) can equally be tightened by using a suitable seal.

The outlet 5 may also be associated with various pieces of equipment which are different from the valve 1, or have their own means of connection and sealing, similar to those on the connecting body 4, to make up, together with the body 4 and ring nut 6, an independent union connection.

The means of connection and sealing, comprising the threaded section 10 and ring 12.

can be dismantled and reused several times, without marked worsening of the seal, due to the capacity for elastic recovery from deformation of the packing 12, made of packing material, which is deformed by the threaded section and compressed against its beat ring.

Claims

1. A connecting union for pipes and the like, the union incorporating means to compensate for assembly errors and comprising two parts of which a first part is a tubular connecting body and the second part is a component for joining to the connecting body one of said parts having at one end a portion having a part-spherical surface capable of forming a sealed coupling with a complementary shaped opening of the other part, said portion being arranged to be pressed against the complementary surface of said opening by a threaded ring nut on one of the parts which can be screwed onto a threaded portion of the other part.

2. A union as claimed in claim 1, wherein said means is provided by said part-spherical surface and said complementary shaped opening being able to rotate relatively to one another, thereby allowing for angular misalignment between said parts.

3. A union as claimed in claim 1 or 2, wherein relative sliding can take place between said part-spherical surface and another portion of said one part, there being sealing means interposed between the two portions and means for preventing the relative sliding, the arrangement being such that the linear extent of the two parts can be varied.

4. A union as claimed in claim 3, wherein said means for preventing said relative sliding comprises a member which is separate from said portion having said part-spherical surface, said member being in the form of a split ring; said threaded ring nut, as it is being screwed onto said threaded portion, being caused to exert a radial action on said split ring which tightens around said another portion of said one part.

5. A union as claimed in any one of the preceding claims, wherein said complementary surface is provided by a shaped sealing ring of a synthetic deformable material.

6. A union as claimed in any one of claims 1 to 4, wherein said complementary surface is provided by an inner frustoconical surface of said opening.

7. A union as claimed in any one of the preceding claims, wherein said first part has means to connect it to another component.

8. A union as claimed in claim 7, wherein said means to connect said first part to another component is provided by said connecting body having at the end that is to be connected to the other component, a threaded portion adjacent which is a packing ring with a frustoconical outer surface, with its largest diameter part being remote from said threaded portion and lying against a beat ring surface of said connecting body, a knurling being provided to prevent the ring rotating in its seat.

9. A union as claimed in claim 8, wherein that part of said packing ring adjacent to said threaded portion has a smaller outer diameter than the outer diameter of said threaded portion and that part of said packing ring adjacent to said beat ring surface has a greater outer diameter than the outer diameter of said threaded portion.

10. A union as claimed in any one of the preceding claims, wherein said second part is a connecting element having, at its end opposite to said opening means for forming a connection and seal with a pipe, valve, tap, a piece of hydraulic equipment or the like.

11. A union as claimed in any one of claims 1 to 9, wherein said second part is a pipe, valve, tap, piece of hydraulic equipment or the like.

1 2. A union as claimed in any one of the preceding claims, wherein it is said first part which has said part-spherical surface and said second part which has said complementary shaped opening.

13. A union as claimed in any one of the preceding claims, wherein said threaded ring nut has a collar which is engageable on said portion of said one part and can be screwed on the first-mentioned threaded portion, which is on said other part, thereby to tighten the two parts together.

14. A connecting union for pipes and the like, substantially as hereinbefore described with reference to Figures 1 and 2, or Figure 3, or Figures 4 and 5 of the accompanying drawings.