ADJUSTABLE PIPE BEND

Abstract: An adjustable pipe bend (10) comprises two half portions (11, 12) each provided with an annular flange (13) which in turn provide circular mating surfaces having a centre at the intersection of the axes (14, 15) and at an angle thereto. The portions (11, 12) can be rotated about the plane of the mating surfaces to provide the desired bend. Portion (11) includes a frusto-conical or cylindrical throat (16) which terminates in a curved portion (17) which forms part of an imaginary sphere (18), and is further joined to the flange (13) by an arcuate portion (19) which also extends as a tangent to the sphere. The longitudinal axis of the throat portion does not extend radially from the centre of the sphere (i.e. is angularly offset from the axis (14)) thus enabling the diameter of the sphere to more closely approach the diameter of the pipe run in which it is located whereby a change in direction of flow through the bend is achieved with minimal disturbance to the flow. Portions (11, 12) need not be identical as shown.

Description: "ADJUSTABLE PIPE BEND" TECHNICAL FIELD The present invention relates to adjustable pipe bends wherein the one bend can accommodate a change in direction throughout a wide range of angles. BACKGROUND ART Known adjustable pipe bends are generally large fittings which offer considerable resistance to the passage of fluid therethrough. They also have a large central cross-section relative to the pipe diameter causing difficulties in tight piping situations. Typical of such bends is that described in U.K. Patent 1,361,662 to Yamamoto Sangyo K.K. The bend of this patent requires a large spherical portion relative to the pipe diameter. Furthermore the flow characteristics within such a bend are inherently turbulent at any reasonable flow rate. Turbulent flow is undesirable for some applications such as slurry transport wherein the increased turbulence greatly accelerates wear on the pipe bend. Similarly U.S. Patents 2,489,100; 1,301,453 and 1,123,839 are directed towards adjustable pipe couplings and means of securing their relative parts together. They have not considered the flow path problems. This is also the case with the present inventor's earlier application as set forth in German Offenlegungschrift 2,325,757. It is the object of the present invention to overcome or substantially ameliorate the above disadvantages. DISCLOSURE OF THE INVENTION There is disclosed herein an adjustable pipe bend having an inlet portion and an outlet portion sealingly connected by circular mating seal surfaces, and wherein at least one of said portions consists of a first throat remote from said surface and a curved part joining said first throat to said surface, and wherein said curved part forms a segment of a sphere on the one side and said first throat is at least partially tangential to said sphere. BRIEF DESCRIPTION OF THE DRAWINGS A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Fig. 1 is a schematic sectioned side elevation of an adjustable pipe bend; Fig. 2 is a schematic sectioned side elevation of one half of the adjustable pipe bend of Fig. 1; Fig. 3 is a schematic end elevation of a portion of the flange of the pipe bend of Fig. 2; and Fig. 4 is a schematic sectioned side elevation of a modified form of the bend of Fig. 1. Fig. 5 is a schematic sectional side elevation of a further modified form of the bend of Fig. 1. MODES OF CARRYING OUT THE INVENTION In Figs. 1 to 3 of the accompanying drawings there is schematically depicted a pipe bend 10. The pipe bend 10 consists of two half portions 11 and 12, which in the present instance are identical. However it should be appreciated that the half portion 12 is viewed at 90° rotation to the half por.tion 11. Each identical half portion 11 and 12 is provided with an annular flange 13, with the flange 13 providing circular mating surfaces having a centre at the intersection of the two axes 14 and 15. The flanges 13 are provided with a plurality of slots (as best seen in Fig. 3) through which bolts or threaded fasteners (not shown) may pass to secure the two half portions 11 and 12 together. Portions 11 and 12 although shown as identical could in fact be different. The half portion 11 includes a first frusto-conical throat 16 defining a passage of increasing cross-sectional area from the pipe connecting end flanges 22 towards the joint flanges 13. The throat part 16 terminates with a curved portion 17 which forms part of an imaginary sphere 18 (Fig. 1). Still further, the throat 16 is joined to the flange 13 by an arcuate portion 19. The portion 19 also extends as a tangent to the imaginary sphere 18. The throat 16 has as its longitudinal axis the axis 22. The throat 16 half portion 12 is also of generally frusto-conical section and extends as a tangent to the sphere 18 . As best seen in Fig. 3, the flanges 13 are provided with a plurality of angularly extending slots 20 which enable the two half portions 11 and 12 to be secured together by threaded fasteners. The slots 20 are spaced and are of adequate length to enable relative rotation between the two half portions 11 and 12 about the axis 15, to provide for angular adjustment between the half portions 11 and 12, to create a bend having an included angle from 90° to 180°. It should be particularly noted that the half portion 11 defines a passage 21 which has a centre extending along the line 22. The line 22 does not extend radially from the centre of the sphere 18. This enables the diameter of the imaginary sphere 18 to more closely approach the diameter of the pipe run into which it is located. If a pipe bend constructed of two half portions identical to the half portion 11, is provided, then relative rotation between the two half portions will enable angular adjustment between the two throats 16 so that the pipe bend can then accommodate an included angular difference between the two half portions of 90° to 180°. Such angular adjustment is accommodated by the flanges 13 providing circular mating surfaces extending at 45° to the axis 14. The axis 14 joins the centre of the throat inlet to the centre of the plane joining the two bend portions. It also is an extension of the flow axis of the pipe to which it is joined. A modification of the pipe bend is shown in Fig. 4 wherein the first portion 11 is identical to the second portion 12 but the radial axis 14 is at a much less angle than 45° to the plane of the joined flanges 13. This allows for moderate bends where an absolute minimum disturbance to the path of flow is required. Further it can be used to join two pipes in a straight run with minimal change of cross sectional area between the flange ends 22. The pipe bend of Fig. 4 is also provided with a lining 23 which is applied to piping for carrying corrosive or erosive substances. The bend, shown in Figure 5 illustrates a further embodiment wherein the ratio of the sphere 18 diameter to the throat 16 diameter is reduced whilst at the same time 5 maintaining an offset of the axis of the throat 22 to the radial axis 14 joining the centre of the imaginary sphere 18 and the centre of the remote end of the throat 16. The throat 16 (Figure 5) is of cylindrical configuration. This therefore allows much greater flexibility to the 10 ratios of the sphere diameter to the throat diameter and allows the sphere to be much reduced in ratio to the throat diameter. The profile shown in Fig. 5 shows the throat 16 of parallel (cylindrical) section between a transition region 1.5 defined by curved portions 17 and 19 adjacent the imaginary sphere 18 and the end flange 22. The throat face at end flange 22 is normal to the radial line 14 from the sphere centre. The throat axis 22 can be seen to be offset to the radial axis 14. 20 . This allows ratios of the throat diameter to the sphere diameter to approach 1:1 and the length of the throat 11 to be minimised if desired. Thus, the one bend is used for all angles, obviating the need to stock numerous bends for each angle. This 25 clearly provides tremendous flexibility and savings in plants having complex piping runs. The above discussed preferred embodiment of the present invention has the advantage of providing a pipe bend which offers minimum resistance to the flow of fluid. This 30 results in lower wear of the pipe bend particularly where the fluid carries with it an abrasive material. Thus it is possible in many situations to maintain a laminar flow regime which avoids the wear caused by turbulance induced in the flow in the prior art devices. Still further, the above discussed preferred embodiment has the advantage of minimising the size of the pipe bend and therefore lowering the cost of manufacture thereof.

Claims: CLAIMS 1. An adjustable pipe bend having an inlet portion and an outlet portion sealingly connected by circular mating seal surfaces, and wherein at least one of said portions consists of a first throat remote from said surface and a curved part joining said first throat to said surface, and wherein said curved part forms a segment of an imaginary sphere on the one side and said first throat is at least partially tangential to said sphere. 2. The bend of claim 1 wherein the second of said portions is identical to the first portion. 3. The bend of claim 1 wherein the throat portion is of frusto-conical shape. 4. The bend of claim 1 wherein an imaginary line from the centre of the inlet to the throat portion to the centre of the plane joining the inlet and outlet portions is approximately 45° to the plane joining the first and second portions, and the axis of said throat deviates from the centre of the inlet until it reaches the centre of the plane joining the inlet and outlet portions. 5. The bend of claim 1 wherein the throat portion is a cylindrical section having 6. The bend of claim 5 wherein the end of the throat portion remote from said imaginary sphere is adapted for attachment to a fitting, said end being terminated in a plane which is normal to an imaginary line joining the centre of the cylindrical end to the centre of the plane joining the first and second portions, and the centre line of the first portion deviates from the centre of the inlet until it reaches the centre of the plane joining the first and second portions.

Inventors: MATHIAS BRYAN JOHN TREGURTHA, MATHIAS, BRYAN, JOHN, TREGURTHA
Applicants: WARMAN INT LTD, WARMAN INTERNATIONAL LIMITED
Application year: 1986
Main classification: F16L27
IPC codes: F16L27