PIPE REPAIR COMPOSITION AND METHOD

Abstract

A method of repairing a pipe and/or a drain. The method involves covering a damaged section (103) of pipe (100) with a binder material (110) and a conductive/dissipative material (120). The conductive/dissipative material (120) is arranged in contact with, suitably within, the binder material (110) and functions to reduce static electrical charge build-up across the binder material, compared to the static charge build-up that may otherwise occur in a comparable section of binder material not having the conductive/dissipative material. The method may reduce the risk of a spark produced by a static electrical discharge across the binder material causing a flammable liquid within the pipe to ignite. The method may therefore provide a safer pipe repair, particularly wherein the pipe is normally used for transporting flammable liquids. A kit, composition, pipe and uses of a kit or composition to repair a pipe are also provided.

Claims

1. A method of repairing a pipe, the method comprising applying, to an internal surface of the pipe at a location of the pipe to be repaired, a binder material and a conductive/dissipative material for reducing static electrical charge build-up across the binder material.

2. The method according to claim 1, wherein the conductive/dissipative material is formed from a conductive material.

3. The method according to claim 1, wherein the binder material and the conductive/dissipative material are applied to the internal surface of the pipe together.

4. The method according to claim 1, wherein the method comprises the steps of: a) applying the binder material to the internal surface of the pipe at the location of the pipe to be repaired; and b) applying the conductive/dissipative material to the internal surface of the pipe at the location of the pipe to be repaired, in contact with the binder material and substantially traversing the binder material.

5. The method according to claim 1, wherein the binder material covers a cylindrical section of the pipe.

6. The method according to claim 1, wherein the conductive/dissipative material is in the form of conductive/dissipative particles.

7. The method according to claim 1, wherein the conductive/dissipative material is in the form of at least one elongate element.

8. The method according to claim 7, wherein the conductive/dissipative material is in the form of a plurality of elongate elements.

9. The method according to claim 8, wherein the elongate elements are provided as a tubular mesh.

10. The method according to claim 1, wherein the conductive/dissipative material comprises copper.

11. (canceled)

12. A composition for repairing a pipe, the composition comprising: a binder material; and a conductive/dissipative material for reducing static charge build-up across the binder material.

13. A pipe comprising at least one section comprising a binder material and a conductive/dissipative material for reducing static charge build-up across the binder material.

14. (canceled)

15. (canceled)

16. The composition of claim 12, wherein the conductive/dissipative material is formed from a conductive material.

17. The composition of claim 12, wherein the conductive/dissipative material is in the form of conductive/dissipative particles.

18. The composition of claim 12, wherein the conductive/dissipative material is in the form of at least one elongate element.

19. The composition of claim 18, wherein the conductive/dissipative material is in the form of a plurality of elongate elements.

20. The composition of claim 19, wherein the elongate elements are provided as a tubular mesh.

21. The composition of claim 12, wherein the conductive/dissipative material comprises copper.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0177] For a better understanding of the invention, and to show how example embodiments may be carried into effect, reference will now be made to the accompanying drawing in which:

[0178] FIG. 1 is a perspective view of a section of a pipe (100) according to the fourth aspect of the present invention which has been repaired by a method of the first aspect of the present invention using a composition of the third aspect of the present invention.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

[0179] FIG. 1 shows a section of pipe (100) comprising an outer surface (101) and an inner surface (102). The pipe comprised damage in the form of crack (103) which formed an opening from the outer surface (101) to the inner surface (102) of the pipe (100). The damage was repaired by combining a binder material (110) with a copper mesh formed into a tube (120), applying the binder material (110) and the tube of copper mesh (120) to the inside surface of the pipe (102) and then allowing the binder material (110) to cure. Once curing was complete, the repaired pipe (100) was obtained having an inside surface covered with solidified binder material (110) partially impregnated with the tubular copper mesh (120).

EXAMPLE SET 1

[0180] By way of example, a method of the first aspect was carried out on a test section of pipe to provide the test section of pipe with a binder material and a conductive/dissipative material for reducing static charge build-up across the binder material.

[0181] The test section of pipe was prepared by combining epoxy resin component parts A and B to produce a binder material, applying the binder material to a copper mesh (either fine or course), wrapping the combined binder material and copper mesh around an expandable member, inserting the expandable member into a section of Thermachem pipe supplied by Naylor Drainage Ltd. (a conductive/dissipative vitrified clay pipe), expanding outwards the expandable member with compressed air so that the combined binder material and copper mesh contacted the internal surface of the pipe, contracting inwards the expandable member by venting the compressed air and removing the expandable member from the pipe to leave the combined binder material and the mesh in place on the pipe.

[0182] The test section of pipe was analogous to the section of pipe (100) shown in FIG. 1 but was not damaged. The test section of pipe had an inside surface covered with solidified binder material (110) partially impregnated with the tubular copper mesh (120).

[0183] This method was used with a coarse copper mesh to provide test pipe 1a and also with a fine copper mesh to provide test pipe 1b.

[0184] The test section of pipe was tested for surface electrical resistivity according to the following procedure.

[0185] The units of surface electrical resistivity are and /sq. It describes the ability of a material to conduct electric charge across its surface and is the reciprocal of the surface conductivity.

Method of Measurement

[0186] The surface resistivity, is calculated using the Ohms' Law formula

[00001]$P.Math.s=\left(\frac{V}{I}\right).Math.k$ [0187] where: [0188] Ps=Surface resistivity of material (in /) [0189] V=Applied voltage [0190] I=Measured Current (in Amperes) [0191] K=Cell constant (length of measuring electrodes (100 mm)/distance between measuring electrodes (10 mm)=10

[0192] A measurement cell was used consisting of a current measuring electrode separated by polytetrafluoroethylene (PTFE) insulation from a parallel voltage application electrode. The measurement cell was then connected to an Electrometer which measured the resultant current across the material between the electrodes.

[0193] The parallel electrode was placed onto various locations of the test specimen or at least 10 mm away from the edges. The cell was energised at 10 V. If the calculated resistance was less than 1.010.sup.6 then this result was recorded and the procedure repeated at other areas on the specimen or on fresh material, if available.

[0194] If the calculated resistance was greater than 1.010.sup.6 but less than 1.010.sup.7 then the test procedure was repeated using 100 V. For measured resistances of between 1.010.sup.7 and 1.010.sup.9, the test procedure was conducted at 500 V. With measured resistances above 1.010.sup.9 the test voltage was raised to 1000 V.

[0195] The calculated resistance (applied voltage/measured current) is then substituted into the above formula to calculate a surface resistivity value, the geometric average of all areas tested was given as the final value of resistivity.

[0196] Most materials adsorb atmospheric water to a lesser or greater extent, which for many materials has a dramatic effect on the surface resistivity. The test was therefore carried out at a relative humidity (RH 505%) and in dryer conditions (RH 252%). In both cases the sample is conditioned at the stated relative humidity for 24 hours prior to testing.

[0197] In the results shown in the Tables below, E is used to denote exponential therefore, for example, 1.8E+07 means 1.810.sup.7.

Test Results for Example Set 1

[0198]

TABLE-US-00001 TABLE 1 Test results with test pipe 1a coarse mesh liner at 50% relative humidity (RH) 50% RH/21 C. - test pipe 1a coarse mesh liner Calculated Surface Current Resistance Resistivity Test Voltage (A) () (/sq) 1 1000 5.5E04 1.8E+06 1.8E+07 2 1000 6.0E04 1.7E+06 1.7E+07 3 1000 1.5E07 6.7E+09 6.7E+10 4 1000 6.0E07 1.7E+09 1.7E+10 5 1000 2.0E07 5.0E+09 5.0E+10 6 1000 1.8E07 5.6E+09 5.6E+10 7 1000 5.0E07 2.0E+09 2.0E+10 8 1000 4.0E04 2.5E+06 2.5E+07 9 1000 5.5E04 1.8E+06 1.8E+07 10 1000 3.8E08 2.6E+10 2.6E+11 Geometric Mean = 2.2E+09

TABLE-US-00002 TABLE 2 Test results with test pipe 1b fine mesh liner at 50% relative humidity (RH) 50% RH/21 C. - test pipe 1b fine mesh liner Calculated Surface Current Resistance Resistivity Test Voltage (A) () (/sq) 1 1000 8.0E06 1.3E+08 1.3E+09 2 1000 2.5E06 4.0E+08 4.0E+09 3 1000 6.3E06 1.6E+08 1.6E+09 4 1000 4.0E04 2.5E+06 2.5E+07 5 1000 1.5E05 6.7E+07 6.7E+08 6 1000 6.0E04 1.7E+06 1.7E+07 7 1000 7.0E05 1.4E+07 1.4E+08 8 1000 7.0E06 1.4E+08 1.4E+09 9 1000 1.0E05 1.0E+08 1.0E+09 10 1000 8.0E05 1.3E+07 1.3E+08 Geometric Mean = 3.8E+08 Pre-test check @ 25% RH/21 C. Voltage(V) Current (A) Resistance() 10 3.0E10 3.3E+10

TABLE-US-00003 TABLE 3 Test results with test pipe 1a coarse mesh liner at 25% relative humidity (RH) 25% RH/21 C. - test pipe 1a coarse mesh liner Calculated Surface Current Resistance Resistivity Test Voltage (A) () (/sq) 1 1000 6.0E04 1.7E+06 1.7E+07 2 1000 3.5E07 2.9E+09 2.9E+10 3 1000 5.5E04 1.8E+06 1.8E+07 4 1000 4.0E04 2.5E+06 2.5E+07 5 1000 1.0E09 1.0E+12 1.0E+13 6 1000 1.5E07 6.7E+09 6.7E+10 7 1000 7.0E08 1.4E+10 1.4E+11 8 1000 6.0E04 1.7E+06 1.7E+07 9 1000 1.3E06 7.7E+08 7.7E+09 10 1000 3.5E07 2.9E+09 2.9E+10 Geometric Mean = 3.1E+09

TABLE-US-00004 TABLE 4 Test results with test pipe 1b fine mesh liner at 25% relative humidity (RH) 25% RH/21 C. - test pipe 1afine mesh liner Calculated Surface Current Resistance Resistivity Test Voltage (A) () (/sq) 1 1000 6.0E04 1.5E+06 1.5E+07 2 1000 2.5E07 4.0E+07 4.0E+08 3 1000 3.0E07 3.3E+09 3.3E+10 4 1000 6.0E04 1.7E+06 1.7E+07 5 1000 3.0E06 3.3E+08 3.3E+09 6 1000 1.8E06 5.6E+08 5.6E+09 7 1000 2.8E06 3.6E+08 3.6E+09 8 1000 6.0E04 1.7E+06 1.7E+07 9 1000 7.0E07 1.4E+09 1.4E+10 10 1000 4.0E07 2.5E+09 2.5E+10 Geometric Mean = 1.0E+09

[0199] All measurements were made on resin layer on the inner surface of pipe.

Summary of Test Results

[0200] The results of the testing completed on test pipe are summarised in Table 5.

TABLE-US-00005 TABLE 5 Summary of results Parameter Surface Resistivity Test Results (/sq) (/sq) - Geometric Mean 50% RH/21 C. 25% RH/21 C. Course mesh liner 2.2E+09 3.1E+09 Fine mesh liner 3.8E+08 1.0E+09

[0201] Across both sections of the pipe tested, there was a wide range of resistivity readings noted.

[0202] This is believed to be down the variability of the resin thickness in proximity to the metallic gauze layer contained within but this was not confirmed. The geometric mean values of the surface resistivity measurements indicate that the inner pipe resin deposit is considered to be dissipative as they fall within the range of 10.sup.5 /sq to 10.sup.12 /sq as per Table 1 of IEC 60079-32-1: 2013.

EXAMPLE SET 2

[0203] The test pipe preparation and experimental procedures described above were repeated for the following alternative test pipe sections. In the method of preparation, the copper powder was combined with the binder material before the binder material was applied to the fibreglass liner (matting) or the copper mesh (matting).

[0204] Test pipe 2a was provided with a simulated repair using the binder material mixed with copper powder and a fibreglass pipe liner (fibreglass matting). The binder material was formed from 200 ml of an epoxy resin part A, 400 ml of an epoxy resin part B and 556 g of copper powder.

[0205] Test pipe 2b was provided with a simulated repair using the binder material mixed with copper powder and a fibreglass pipe liner (fibreglass matting). The binder material was formed from 200 ml of an epoxy resin part A, 400 ml of an epoxy resin part B and 1112 g of copper powder.

[0206] Test pipe 2c was provided with a simulated repair using the binder material mixed with copper powder and a fine copper mesh (copper matting). The binder material was formed from 200 ml of an epoxy resin part A, 400 ml of an epoxy resin part B and 1112 g of copper powder.

[0207] Test pipe 2d was provided with a simulated repair using the binder material mixed with copper powder and a fine copper mesh (copper matting). The binder material was formed from 200 ml of an epoxy resin part A, 400 ml of an epoxy resin part B and 556 g of copper powder.

[0208] Test pipe 2e was provided with a simulated repair using the binder material mixed with a pipe liner formed by needling/interweaving a fine copper mesh (copper matting) into a fibreglass pipe liner such that the copper mesh is exposed to the inside of the test section of pipe.

[0209] Comparative test pipe 2f was provided by an unrepaired section Thermachem vitrified clay pipe, therefore having no binder material, matting or mesh on the inside surface.

TABLE-US-00006 TABLE 6 Test results for test pipe 2a: fibreglass matting, 556 g copper powder Test Voltage Current Resistance Surface Resistivity # (V) (A) () (/sq) Relative humidity = 50% 1 1000 1.2E05 8.3E+07 8.3E+08 2 1000 1.0E04 1.0E+07 1.0E+08 3 1000 7.5E06 1.3E+08 1.3E+09 4 1000 4.5E06 2.2E+08 2.2E+09 5 1000 1.2E05 8.3E+07 8.3E+08 6 1000 7.5E06 1.3E+08 1.3E+09 7 1000 4.5E05 2.2E+07 2.2E+08 8 1000 4.5E05 2.2E+07 2.2E+08 9 1000 2.5E05 4.0E+07 4.0E+08 10 1000 4.5E06 2.2E+08 2.2E+08 Geometric Mean = 5.1E+08 Relative humidity = 25% 1 1000 9.2E06 1.1E+08 1.1E+09 2 1000 1.6E05 6.3E+07 6.3E+08 3 1000 1.2E05 8.3E+07 8.3E+08 4 1000 1.0E05 1.0E+08 1.0E+09 5 1000 4.5E06 2.2E+08 2.2E+09 6 1000 4.5E06 2.2E+08 2.2E+09 7 1000 7.4E06 1.3E+08 1.3E+09 8 1000 2.5E05 4.0E+07 4.0E+08 9 1000 5.3E06 1.9E+08 1.9E+09 10 1000 5.0E06 2.0E+08 2.0E+09 Geometric Mean = 1.2E+09

TABLE-US-00007 TABLE 7 Test results for test pipe 2b: fibreglass matting, 1112 g copper powder Test Voltage Current Resistance Surface Resistivity # (V) (A) () (/sq) Relative humidity = 50% 1 1000 2.6E05 4.0E+07 4.0E+08 2 1000 6.0E04 1.7E+06 1.7E+07 3 1000 6.0E04 1.7E+06 1.7E+07 4 1000 5.9E04 1.7E+06 1.7E+07 5 1000 6.0E04 1.7E+06 1.7E+07 6 1000 6.0E04 1.7E+06 1.7E+07 7 1000 5.0E05 2.0E+07 2.0E+08 8 1000 5.9E04 1.7E+06 1.7E+07 9 1000 1.1E04 9.1E+06 9.1E+07 10 1000 8.0E05 1.3E+07 1.3E+08 Geometric Mean = 4.3E+07 Relative humidity = 25% 1 1000 2.3E05 4.3E+07 4.3E+08 2 1000 5.3E04 1.9E+06 1.9E+07 3 1000 5.7E04 1.8E+06 1.8E+07 4 1000 2.5E05 4.0E+07 4.0E+08 5 1000 3.7E05 2.7E+07 2.7E+08 6 1000 1.4E05 7.1E+07 7.1E+08 7 1000 4.4E05 2.3E+07 2.3E+08 8 1000 5.7E04 1.8E+06 1.8E+07 9 1000 5.8E04 1.7E+06 1.7E+07 10 1000 4.5E04 2.2E+06 2.2E+07 Geometric Mean = 8.4E+07

TABLE-US-00008 TABLE 8 Test results for test pipe 2c: copper matting, 1112 g copper powder Test Voltage Current Resistance Surface Resistivity # (V) (A) () (/sq) Relative humidity = 50% 1 1000 5.8E04 1.7E+06 1.7E+07 2 1000 6.0E04 1.7E+06 1.7E+07 3 1000 5.8E04 1.7E+06 1.7E+07 4 1000 8.0E04 1.3E+06 1.3E+07 5 1000 6.5E04 1.5E+06 1.5E+07 6 1000 8.0E04 1.3E+06 1.3E+07 7 1000 7.3E04 1.4E+06 1.4E+07 8 1000 6.8E04 1.5E+06 1.5E+07 9 1000 7.3E04 1.4E+06 1.4E+07 10 1000 9.0E04 1.1E+06 1.1E+07 Geometric Mean = 1.5E+07 Relative humidity = 25% 1 1000 6.0E06 1.7E+08 1.7E+09 2 1000 4.3E05 2.3E+07 2.3E+08 3 1000 6.0E04 1.7E+06 1.7E+07 4 1000 5.5E04 1.8E+06 1.8E+07 5 1000 5.0E04 2.0E+06 2.0E+07 6 1000 5.8E04 1.7E+06 1.7E+07 7 1000 5.3E04 1.9E+06 1.9E+07 8 1000 4.1E04 2.4E+06 2.4E+07 9 1000 5.5E04 1.8E+06 1.8E+07 10 1000 6.0E04 1.7E+06 1.7E+07 Geometric Mean = 3.8E+07

TABLE-US-00009 TABLE 9 Test results for test pipe 2d: copper matting, 556 g copper powder Test Voltage Current Resistance Surface Resistivity # (V) (A) () (/sq) Relative humidity = 50% 1 1000 6.0E04 1.7E+06 1.7E+07 2 1000 5.7E04 1.8E+06 1.8E+07 3 1000 8.5E04 1.2E+06 1.2E+07 4 1000 5.8E04 1.7E+06 1.7E+07 5 1000 1.7E07 5.9E+09 5.9E+10 6 1000 6.0E04 1.7E+06 1.7E+07 7 1000 5.7E04 1.8E+06 1.8E+07 8 1000 7.5E04 1.3E+06 1.3E+07 9 1000 5.6E04 1.8E+06 1.8E+07 10 1000 6.0E04 1.7E+06 1.7E+07 Geometric Mean = 3.7E+07 Relative humidity = 25% 1 1000 6.0E04 1.7E+06 1.7E+07 2 1000 7.0E04 1.4E+06 1.4E+07 3 1000 5.7E04 1.8E+06 1.8E+07 4 1000 3.7E05 2.7E+07 2.7E+08 5 1000 6.2E04 1.6E+06 1.6E+07 6 1000 5.8E04 1.7E+06 1.7E+07 7 1000 5.3E04 1.9E+06 1.9E+07 8 1000 6.0E04 1.7E+06 1.7E+07 9 1000 6.0E04 1.7E+06 1.7E+07 10 1000 6.0E04 1.7E+06 1.7E+07 Geometric Mean = 2.2E+07

TABLE-US-00010 TABLE 10 Test results for test pipe 2e: pipe liner formed by needling/interweaving a fine copper mesh (copper matting) into a fibreglass pipe liner Test Voltage Current Resistance Surface Resistivity # (V) (A) () (/sq) Relative humidity = 50% 1 500 5.8E04 8.6E+05 8.6E+06 2 500 1.5E05 3.3E+02 3.3E+08 3* 500 2.3E13 6.8E+14 6.8E+15 4 500 6.5E04 7.7E+05 7.7E+06 5 500 5.8E04 8.6E+05 8.6E+06 6 500 5.8E04 8.6E+05 8.6E+06 7 500 2.5E04 2.0E+06 2.0E+08 8* 500 5.5E12 9.1E+13 9.1E+14 9* 500 1.0E11 5.0E+13 5.0E+14 10* 500 1.0E11 5.0E+13 5.0E+14 Geometric Mean = 2.3E+10 Relative humidity = 25% 1 500 5.8E04 8.6E+05 8.6E+06 2 500 6.0E12 8.3E+13 8.3E+14 3 500 3.5E12 1.4E+14 1.4E+15 4 500 6.0E04 8.3E+05 8.3E+06 5 500 4.0E10 1.3E+12 1.3E+13 6 500 2.5E10 2.0E+12 2.0E+13 7 500 2.0E03 2.5E+07 2.5E+08 8 500 2.5E11 2.0E+13 2.0E+14 9 500 1.0E11 5.0E+13 5.0E+14 10 500 1.5E11 3.3E+13 3.3E+14 Geometric Mean = 1.7E+12

TABLE-US-00011 TABLE 10 Test results for comparative test pipe 2f: no simulated repaired section Test Voltage Current Resistance Surface Resistivity # (V) (A) () (/sq) Relative humidity = 50% 1 1000 2.3E07 4.3E+09 4.3E+10 2 1000 1.4E07 7.1E+09 7.1E+10 3 1000 2.0E07 5.0E+09 5.0E+10 4 1000 3.1E07 3.2E+09 3.2E+10 5 1000 1.4E07 7.1E+09 7.1E+10 6 1000 2.1E07 4.8E+09 4.8E+10 7 1000 3.8E07 2.6E+09 2.6E+10 8 1000 3.5E08 2.9E+10 2.9E+10 9 1000 1.6E08 6.3E+10 6.3E+10 10 1000 4.5E08 2.2E+10 2.2E+10 Geometric Mean = 4.2E+10 Relative humidity = 25% 1 1000 1.5E09 6.7E+11 6.7E+12 2 1000 5.5E09 1.8E+11 1.8E+12 3 1000 5.0E09 2.0E+11 2.0E+12 4 1000 1.3E08 7.7E+10 7.7E+11 5 1000 3.0E09 3.3E+11 3.3E+12 6 1000 2.3E09 4.3E+11 4.3E+12 7 1000 1.0E09 1.0E+12 1.0E+13 8 1000 3.7E09 2.7E+11 2.7E+12 9 1000 3.0E09 3.3E+11 3.3E+12 10 1000 3.5E09 2.9E+11 2.9E+12 Geometric Mean = 3.0E+12

[0210] These results show that a repaired section of a pipe has a surface electrical resistivity which classifies it as dissipative, after a method of the first aspect has been carried out. Specifically the results above show that a test section of pipe having a simulated repair section formed from either a binder material with a copper mesh (Tables 1-5), a binder material comprising copper powder with a fibreglass pipe liner (Tables 6 and 7), a binder material comprising a copper powder with a copper mesh (Tables 8 and 9) or a binder material with a copper mesh interwoven with a fibreglass pipe liner (Table 10) all provide a simulated repaired section of pipe which is dissipative. Such test sections of pipe show comparable or improved dissipative properties compared to an unrepaired section of the same pipe (Table 11).

[0211] This means that such a repaired section, when used on a damaged pipe of the type discussed above, would have a sufficient conductivity in the repaired part to reduce, suitably prevent, static charge build-up across the repaired part of the pipe and therefore reduce the risk of a spark produced by a static electrical discharge across the binder material causing a flammable liquid within the pipe to ignite. The results therefore show that the method of the first aspect may provide a safer pipe repair, particularly wherein the pipe is normally used for transporting flammable liquids, and may therefore protect the pipework, associated plant and pipe/plant operators from damage or injury caused by sparks produced by static electrical discharge.

[0212] In summary, the present invention provides a method of repairing a pipe and/or a drain. The method involves covering a damaged section of pipe with a binder material and a conductive/dissipative material. The conductive/dissipative material is arranged in contact with, suitably within, the binder material and functions to reduce static electrical charge build-up across the binder material, compared to the static charge build-up that may otherwise occur in a comparable section of binder material not having the conductive/dissipative material. The method may reduce the risk of a spark produced by a static electrical discharge across the binder material causing a flammable liquid within the pipe to ignite. The method of this first aspect may therefore provide a safer pipe repair, particularly wherein the pipe is normally used for transporting flammable liquids. A kit, composition, pipe and uses of a kit or composition to repair a pipe are also provided.

[0213] The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each aspect or exemplary embodiment of the invention as set out herein are also to be read as applicable to any other aspect or exemplary embodiments of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each exemplary embodiment of the invention as interchangeable and combinable between different exemplary embodiments.

[0214] Throughout this specification, the term comprising or comprises means including the component(s) specified but not to the exclusion of the presence of other components. The term consisting essentially of or consists essentially of means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effect of the invention. Typically, when referring to compositions, a composition consisting essentially of a set of components will comprise less than 5% by weight, typically less than 3% by weight, more typically less than 1% by weight of non-specified components.

[0215] The term consisting of or consists of means including the components specified but excluding addition of other components.

[0216] Whenever appropriate, depending upon the context, the use of the term comprises or comprising may also be taken to encompass or include the meaning consists essentially of or consisting essentially of, and may also be taken to include the meaning consists of or consisting of.

[0217] Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

[0218] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0219] All of the features disclosed in this specification (including any accompanying claims, and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0220] Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0221] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.