Multi-taper plug valve

1. A high pressure plug valve comprising:

a valve body having an annular inner surface facing towards a central axis, the inner surface of the valve body having a first taper relative to the central axis; and

an annular body saver insert having an annular outer surface facing away from the central axis, the outer surface of the body saver insert having a second taper relative to the central axis, the outer surface of the annular body saver insert adapted to interface with the annular inner surface of the valve body with a tapered interference fit;

wherein the body saver insert includes a main portion and a t-shaped projection extending from the main portion in a direction away from the central axis; and

wherein the t-shaped projection includes a bridge connected on a radially inner end to the main portion of the body saver insert and connected on a radially outer end to a circumferential seal disposed circumferentially around the central axis, an outer surface of the circumferential seal defining at least part of the outer surface of the body saver insert; and

wherein, when viewed in cross section along a plane through the central axis, the bridge has a first width measured in a direction parallel to the central axis and the circumferential seal has a second width measured in a direction parallel to the central axis, the second width of the circumferential seal being greater than the first width of the bridge.

2. The high pressure plug valve of claim 1 , further comprising a plug having a tapered outer surface adapted to interface with a tapered inner surface of the annular body saver with a tapered interference fit.

3. The high pressure plug valve of claim 1 , wherein the bridge connecting the circumferential seal to the main portion of the body saver insert can slightly flex to provide flexible metal interference sealing between the circumferential seal and the valve body.

4. The high pressure plug valve of claim 1 , wherein the outer surface of the annular body saver and the annular inner surface of the valve body provide a metal-to-metal tapered interference fit.

5. The high pressure plug valve of claim 1 , wherein the annular body saver is inserted into a first end of a cavity defined by the valve body and further comprising a first cap and a first nut for retaining the annular body saver insert within the cavity.

6. The high pressure plug valve of claim 5 , further comprising:

a plug is inserted into an opposing second end of the cavity defined by the valve body, and

a second cap and a second nut for retaining the plug within the cavity.

7. The high pressure plug valve of claim 1 , further comprising:

a valve plug including sealing surfaces and a flow bore; and

a plug saver having a flow bore and adapted to receive the valve plug for covering the sealing surfaces of the valve plug such that the flow bore of the valve plug and the flow bore of the plug saver are aligned.

8. The high pressure plug valve of claim 7 , further comprising grooves on an outer surface of the valve plug for receiving grease.

9. The high pressure plug valve of claim 7 , further comprising at least one seal disposed on an outer surface of the plug saver for sealing contact with an outer surface of the valve plug.

10. The high pressure plug valve of claim 7 , wherein the plug saver comprises a plurality of separable parts.

11. The high pressure plug valve of claim 7 , wherein the plug saver is adapted to slide over the valve plug and is retained by a pattern of opposing interfering surfaces on the valve plug and plug saver.

12. The high pressure plug valve of claim 11 , wherein the pattern of opposing interfering surfaces comprises a polygon.

13. A high pressure plug valve comprising:

a valve body having an annular inner surface facing towards a central axis, the inner surface of the valve body having a first taper relative to the central axis; and

an annular body saver insert having an annular outer surface facing away from the central axis, the outer surface of the body saver insert having a second taper relative to the central axis, the outer surface of the annular body saver insert adapted to interface with the annular inner surface of the valve body with a tapered interference fit;

a plug disposed on the central axis;

an annular sleeve having an annular inner surface facing toward the central axis for receiving the plug and having an annular outer surface facing away from the central axis, the annular outer surface being tapered relative to the central axis; and

a tapered insert having an annular inner surface facing toward the central axis, the annular inner surface of the tapered insert being tapered relative to the central axis for providing an interference fit with the tapered outer surface of the annular sleeve and having an outer surface facing away from the central axis for interfacing with an inner surface of the annular body saver insert, the inner surface of the annular body insert saver facing toward the central axis.

14. The high pressure plug valve of claim 13 , wherein the annular body saver insert includes a flow aperture adapted for alignment with a flow bore of the valve body and further comprising a bore insert having a first seal adapted to be received within the flow aperture of the annular body saver insert and a second seal adapted to be received within the flow bore of the valve body.

15. The high pressure plug valve of claim 13 , wherein the annular sleeve comprises a pair of Z-shaped slots cut entirely through a sidewall of the annular sleeve on opposing sides and at ninety degrees to a flow bore of the valve body; and

wherein each Z-shaped slot comprises a continuous slot having a first vertical oriented slot portion connected to a first end of a diagonal oriented slot portion and a second vertical oriented slot portion connected to a second end of the diagonal oriented slot portion.

16. The high pressure plug valve of claim 13 , wherein the annular sleeve comprises a plurality of separable parts.

17. A body saver insert for use with a plug valve having a valve body with an annular inner surface facing towards a central axis, the inner surface of the valve body having a first taper relative to the central axis, the body saver insert comprising:

an annular body having an annular outer surface facing away from the central axis, the outer surface of the annular body having a second taper relative to the central axis, the outer surface of the annular body adapted to interface with the annular inner surface of the valve body with a tapered interference fit;

wherein the annular body includes a main portion and a t-shaped projection extending from the main portion in a direction away from the central axis; and

wherein the t-shaped projection includes a bridge connected on a radially inner end to the main portion of the annular body and connected on a radially outer end to a circumferential seal disposed circumferentially around the central axis, the outer portion of the circumferential seal defining at least part of the outer surface of the annular body; and

wherein, when viewed in cross section along a plane through the central axis, the bridge has a first width measured in a direction parallel to the central axis and the circumferential seal has a second width measured in a direction parallel to the central axis, the second width of the circumferential seal being greater than the first width of the bridge.

18. The body saver insert of claim 17 , wherein the outer surface of the annular body of the body saver is adapted to create a metal-to-metal tapered interference fit with the annular inner surface of the valve body.

19. The body saver insert of claim 17 , wherein the annular body includes a flow aperture adapted for alignment with a flow bore of the valve body.

20. The body saver insert of claim 17 , wherein the bridge connecting the circumferential seal to the main portion of the annular body can slightly flex to provide flexible metal interference sealing between the circumferential seal and the valve body.