GB2264339A - Improvements in or relating to branch pipe fittings - Google Patents

Abstract

The fitting for the connection of a branch pipe, typically of similar outside diameter, to a main pipe comprises first 1 and second 2 clamp members for location about the main pipe so as to at least partially encircle it; first clamp member 1 having, extending generally transversely therefrom, a formation 7 to which the branch can be connected; at least one bridging plate 3, 4, extending circumferentially between and overlapping in use the clamp members 1, 2 such that the clamp members 1, 2 and the bridging plate or plates 3, 4 together completely encircle the pipe; at least one gasket 5, 6 for location between the pipe and clamp members 1, 2 and compression therebetween to form a seal between the pipe and clamp; and means 9, 13 for drawing clamp members 1, 2 together about the pipe to compress gasket 5, 6. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO PIPE FITTINGS The invention relates to a pipe fitting for clamping about a pipe to enable the connection thereto of a branch pipe of up to a similar nominal diameter.

It is to be understood that the expression "pipe" as used herein means pipes and tubes as such and also pipelike members and fittings for use in pipe work.

Pipe fittings are known which comprise two generally hemi-cylindrical clamp members which are fitted about a pipe and are clamped thereto by means of clamping bolts. A sealing gasket is disposed between the clamp members and the pipe in order to ensure a fluid-tight seal. Such pipe fittings, for example those sold under the trade name "EasiClamp" by Viking Johnson Limited Hitchin UK, are intended as pipe repair fittings. Thus the fitting is clamped about a damaged part of a pipe, for example a portion of pipe in which there is a crack, corrosion damage or impact damage, thereby to serve as a form of bandage around the pipe. In a modification to the aforesaid types of pipe fitting, there is known a two-part clamp fitting in which a threaded outlet is provided to enable a branch pipe to be connected. Such a fitting is sold by Viking Johnson Limited under the trade mark "EasiTap".However, the aforesaid fitting provides for the securing thereto of a branch pipe of considerably smaller diameter than the main pipe about which the clamp is disposed.

Such known forms of pipe clamp make use of the relative flexibility of a ductile material in order to conform to the outside of the pipe. This feature is important, in that it enables the clamp to accommodate O.D. variations of up to 17% of a pipe relative to its nominal size. For example, a variation of 17mm in outside diameter is not unusual in pipes of 155mm nominal outside diameter. The aforesaid forms of construction clamp are not suited to fittings wherein it is designed to have a provision for connecting to the main pipe a branch pipe of similar diameter to the main pipe. This is because the addition of such a branch stiffens the casting considerably to the point where it will not bend to the shape of the pipe.As a consequence, the pressure exerted by the pipe clamp on the pipe is not uniform around the circumference of the pipe, and this can lead to problems with regard to efficient sealing. This can be a significant disadvantage where, for example, the pipe is intended to convey fluids, such as water or gas under pressure.

It is an object of the present invention to overcome the aforesaid problem and to provide a pipe fitting which enables a mains pipe to be connected to a branch pipe of similar outside diameter to the said mains pipe such that the resulting joint is able to withstand the internal pressures generated in use without leakage occurring.

Accordingly, in one aspect, the invention provides a pipe fitting for clamping about a main pipe to enable the connection thereto of a branch pipe of similar outside diameter to the main pipe; the pipe fitting comprising first and second clamp members for location about the main pipe so as to at least partially encircle the said pipe; the first clamp member having extending generally transversely therefrom, a formation to which the branch pipe can be connected; at least one bridging plate extending circumferentially between and overlapping with the first and second clamp members such that in use the first and second clamp members and the bridging plate or plates together completely encircle the pipe; at least one gasket for location between the pipe and the clamp members and compression therebetween to form a seal between the pipe and clamp; and means for drawing the first and second clamp members together about the pipe to provide the said compression.

The bridging plate or plates, together with the second clamp member, in use preferably extend around at least two thirds of the pipe circumference, and more preferably at least three quarters of the circumference of the pipe In another aspect, the invention provides a pipe fitting for clamping about a main pipe to enable the connection thereto of a branch pipe; the pipe fitting comprising first and second clamp members for location about the main pipe so as to at least partially encircle the said pipe; the first clamp member having extending generally transversely therefrom, a formation to which the branch pipe can be connected; at least one bridging plate extending circumferentially between and overlapping with the first and second clamp members such that in use the first and second clamp members and the bridging plate or plates together completely encircle the pipe; at least one gasket for location between the pipe and the clamp members and compression therebetween to form a seal between the pipe and clamp; and means for drawing the first and second clamp members together about the pipe to provide the said compression; wherein the bridging plate or plates, together with the second clamp member, in use extend around at least two thirds of the pipe circumference, and more preferably at least three quarters of the circumference of the pipe.

The formation to which the branch pipe can be connected can take the form of a tubular portion extending transversely of the clamp member. The tubular portion can be, for example, flanged to permit the connection thereto of a correspondingly flanged branch pipe. Alternatively, it can be threaded, internally or externally. In another embodiment, the formation can take the form of a thickened or reinforced portion of the first clamp member, which portion can be bored or drilled to permit the attachment of a branch pipe. The thickened or reinforced portion of the clamp member typically will be formed as a transverse protrusion of generally circular plan.

It is preferred that there are two bridging plates and, most preferably, these are disposed symmetrically with respect to the first clamp member.

The bridging plates may be hingedly associated with the first clamp member. Thus, each plate can be hinged about a hinge axis parallel to the longitudinal axis of the pipe fitting. It is preferred that the circumferential distance between the hinge axes of the two bridging plates is no greater than one third, and most preferably is less than one quarter, of the circumference of a pipe to which the fitting is to be clamped.

Preferably two gaskets are provided, one being associated with each of the two clamp members. The gasket associated with the first clamp member, preferably extends circumferentially beyond the edges of the clamp member and more preferably beyond the circumferential extent of the bridging plates. In one embodiment, the bridging plates are hingedly associated with the first clamp member by virtue of being held in recesses in the radially outer wall of the gasket, the material of the gasket functioning as the hinge.

The second clamp member is conveniently formed of a material such as ductile iron which permits a certain amount of deformation under an applied force such that, when clamped about a pipe of larger or smaller outside diameter than the inner radius of the clamp member, the clamp member can be deformed to conform more closely to the curvature of the pipe.

The combination of the deformability of the second clamp member, and the presence of the hinged plates, means that the pipe fittings can more easily accommodate a range of pipes of varying outside diameters, in such a way that a more even compressive force is applied to the gasket around the pipe. This ensures a more efficient seal than would be possible in the absence of the bridging plates.

The invention will now be described in more detail by reference to the exemplary embodiments illustrated in Figures 1 to 3 in which: Figure 1 is a side elevation of one embodiment of the invention; Figure 2 is an exploded sectional view along line Z-Z in Figure 1; Figure 3 is a side elevation of the bridging plate used in the embodiment illustrated in Figures 1 and 2; Figure 4 is a cross-sectional view of the bridging plate along line X-X in Figure 3; Figure 5 is a cross-sectional view of the bridging plate along lines Y-Y in Figure 3; and Figure 6 is a fragmentary isometric view showing the arrangement of the bridging plate, gasket and castings similar to those of the embodiments shown in Figures 1 to 5.

Referring to Figures 1 and 2, it can be seen that the clamp comprises first and second clamp members (1) and (2) which together encircle the greater part of the circumference of a pipe (not shown) clamped therebetween.

The clamp further comprises bridging plates (3) and (4) and gaskets (5) and (6). The construction of the bridging plate is illustrated in more detail in Figures 4, 5 and 6 whilst the interconnection of bridging plates, gaskets and clamp members is illustrated in greater detail in Figure 6.

Clamp member (1) has a saddle portion (la) which is disposed about a portion of the circumference of the pipe.

A tubular portion (7) extends transversely from the saddle portion (la) and terminates in an opening encircled by a flange (8). In this embodiment flange (8) is configured is such a way as to be securable in standard fashion to an abutting flange on a branch pipe. However, it could equally be provided with alternative means for securing to the branch pipe.

On either side of the clamp member (1) there are provided pairs of clamp bolt seats (9) in which are located the heads of clamp bolts (10). Disposed around and in contact with the inner surface of the saddle portion (la) of clamp member (1) is a gasket (5), which is formed of an appropriate elastomeric material. The gasket can be provided with a pattern, regular or irregular, of surface projections, for example in the form of a "Waffle" or "Grid" so as to accommodate any irregularities in the surface of the pipe about which the fitting is to be clamped.

The gasket (5) is formed so as to encircle approximately three quarters or more of the circumference of the pipe and is tapered in cross-section towards its ends (11). The central portion of the gasket has a circular cut-out which corresponds approximately to the internal bore of tubular portion (7) of the clamp member (1). At each axial end of the saddle portion (la) of clamp member (1), there is provided a radially inwardly projecting peripheral flange (12), the purpose of which is to help retain the gasket (5) in place.

The connector also comprises a second clamp member (2) which has an approximately semicircular cross-section and is provided along both edges with pairs of clamp bolt seats (13), which are constructed so as to receive the ends of clamp bolts (10). The member (2) is lined about its inner surface (14) by a gasket (6) which can be formed of a material similar or identical to gasket (5) and can also be provided with ridges and/or projections on its inner surface, for example in the form of a "Grid" or a "Waffle" pattern. Gasket (6) also tapers in cross-section at its end (15). The gasket is also held in place by means of radially inwardly projecting peripheral flanges (16) at each axial end of clamp member (2).

Bridging plates (3) and (4) are disposed so as to bridge any gap between clamp member (1) and (2). Thus as can be seen from Figures 1 and 6, the bridging plates are held within recesses (17) and (18) of gaskets (5), for example by means of a suitable adhesive.

In use, the clamping members (1) and (2) and the associated bridging plates and gaskets are placed about the pipe and are drawn together by tightening the bolts (10), thereby compressing the gaskets against the pipe to form a seal. Once the clamp has been clamped into place, a branch pipe can be fitted to the flange of the tubular portion (7), a suitably sized hole first having been bored in the wall of the pipe at the inner end of the tubular portion (7).

The chief advantage arising from the use of the bridging plates is that it enable pipes of varying outside diameter to be accommodated within the clamp with no loss of the integrity of the seal between the clamp and pipe.

The combination of the bridging plates (3) and (4), and the relative flexibility of the clamp member (2) means that as the various component parts of the pipe fitting are drawn together by bolts (10), the pressure applied to the pipe is relatively even around the circumference of the pipe.

As will be appreciated, numerous modifications and alterations may be made to the pipe fitting illustrated in Figures 1 to 6 without departing from the principles underlying the invention. All such modifications and alterations are intended to be embraced by this application.

Claims (16)

1. A pipe fitting for clamping about a main pipe to enable the connection thereto of a branch pipe; the pipe fitting comprising first and second clamp members for location about the main pipe so as to at least partially encircle the said pipe; the first clamp member having extending generally transversely therefrom, a formation to which the branch pipe can be connected; at least one bridging plate extending circumferentially between and overlapping with the first and second clamp members such that in use the first and second clamp members and the bridging plate or plates together completely encircle the pipe; at least one gasket for location between the pipe and the clamp members and compression therebetween to form a seal between the pipe and clamp; and means for drawing the first and second clamp members together about the pipe to provide the said compression.

2. A pipe fitting according to Claim 1 arranged to enable the connection thereto of a branch pipe of similar outside diameter to the main pipe.

3. A pipe fitting according to Claim 1 or Claim 2 wherein the bridging plate or plates, together with the second clamp member is use extend around at least two thirds of the pipe circumference.

4. A pipe fitting according to Claim 3 wherein the bridging plate or plates, together with the second clamp member, in use extend around at least three quarters of the circumference of the pipe.

5. A pipe fitting according to any one of the preceding Claims wherein the formation to which the branch pipe can be connected is in the form of a tubular portion extending transversely of the clamp member.

6. A pipe fitting according to any one of Claims I to 4 wherein the formation to which the branch pipe can be connected takes the form of a thickened or reinforced portion of the first clamp member, which portion can be bored or drilled to permit the attachment thereto of a branch pipe.

7. A pipe fitting according to any one of the preceding Claims wherein there are two bridging plates.

8. A pipe fitting according to Claim 7 wherein the two bridging plates are disposed symmetrically with respect to the first clamp member.

9. A pipe fitting according to Claim 8 wherein the bridging plates are hingedly associated with the first clamp member, and each plate is hinged about a hinge axis parallel to the longitudinal axis of the pipe fitting.

10. A pipe fitting according to Claim 9 wherein the circumferential distance between the hinge axes of the two bridging plates is no greater than one third of the circumference of the pipe to which the fitting is to be clamped.

11. A pipe fitting according to Claim 10 wherein the said circumferential distance is less than one quarter of the circumference of the said pipe to which the fitting is to be clamped.

12. A pipe fitting according to any one of the preceding Claims wherein there are provided two gaskets, one associated with each of the two clamp members.

13. A pipe fitting according to Claim 12 wherein the gasket associated with the first clamp member extends circumferentially beyond the edges of the clamp member.

14. A pipe fitting according to any one of Claims 7 to 11 wherein the bridging plates are hingedly associated with the first clamp member by virtue of being held in recesses in the radially outer wall of the gasket, the material of the gasket functioning as a hinge.

15. A pipe fitting according to any one of the preceding claims wherein the second clamp member is formed of ductile iron.

16. A pipe fitting substantially as described herein with reference to Figures 1 to 6.