Connection and protective ring therefor

1. A connection comprising:

first and second lined tubular members having a coincident bore and a protective ring, the first lined tubular member having a pin end and the second lined tubular member having a box end, each lined tubular member comprising a tubular body having an internal surface of constant diameter, an annular liner and a mortar filled annulus therebetween;

wherein the box end has a sealing surface and the pin end has a corresponding sealing surface for providing a seal;

wherein said mortar filled annulus has an annular recess therein at at least one of the pin end and box end configured to receive a part of the protective ring upon connection of the first and second tubular members;

wherein the protective ring comprises a central body having a cylindrical internal surface configured to be coincident with an inner surface of one of the annular liners.

2. A connection as claimed in claim 1 , wherein the annular recess is defined by said annular liner, said tubular member and said mortar.

3. A connection as claimed in claim 1 , wherein the annular recess is defined by said annular liner, said tubular member and an O-ring.

4. A connection as claimed in claim 1 , wherein the protective ring comprises a flange received in said annular recess.

5. A connection as claimed in claim 4 , wherein the depth of the flange is substantially equal to the thickness of the mortar filled annulus.

6. A connection as claimed in claim 4 , wherein the flange has a pointed distal end.

7. A connection as claimed in claim 1 , wherein said annular recess is located in said pin end and a further annular recess is located in said box end.

8. A connection as claimed in claim 7 , wherein the protective ring comprises a flange received in said annular recess and a further flange received in said further annular recess.

9. A connection as claimed in claim 8 , wherein said further flange is adhered or has a friction fit in said further annular recess.

10. A connection as claimed in claim 1 , wherein the box end has at least one thread and the pin end has a corresponding thread arranged along a first diameter.

11. A connection comprising first and second lined tubular members having a coincident bore and a protective ring, the first lined tubular member having a pin end and the second lined tubular member having a box end, each lined tubular member comprising a tubular body, an annular liner and a mortar filled annulus therebetween, the box end having a sealing surface and the pin end having a corresponding sealing surface for providing a seal; wherein said mortar filled annulus has an annular recess therein at each of the pin end and box end, said protective ring is a single unitary piece including a body having a side and flanges extending therefrom, the flanges having a depth substantially equal to the thickness of said mortar filled annulus, the flanges received in said pin end and box end annular recesses.

12. A connection as claimed in claim 11 , wherein the body has an inner surface substantially coincident with an inner surface of said liner.

13. A lined tubular member comprising:

an annular liner;

a tubular body;

a box end including a sealing surface configured to provide a seal with a corresponding sealing surface of a pin end;

the annular liner arranged in the tubular body, the tubular body of constant diameter along the length of the liner;

a mortar filled annulus between the annular liner and the tubular body, wherein said mortar filled annulus comprises an annular recess; and

a protective ring comprising a body and a flange and a further flange, the further flange being disposed in said annular recess, wherein the body has a cylindrical internal surface coincident with an inner surface of the annular liner.

14. A lined tubular member as claimed in claim 13 , wherein said further flange is adhered in said annular recess.

15. A lined tubular member as claimed in claim 13 , wherein said further flange is friction fitted in said annular recess.