Rotary union with expanding ring

1. A rotary union, comprising:

a housing having a fluid inlet;

a rotating machine component rotatably supported in the housing;

a rotating seal member associated with the rotating machine component;

a non-rotating seal member slidably and sealably disposed within the housing adjacent the rotating seal member;

an expandable seal disposed between and sealably engaging a bore in each of the non-rotating seal member and the housing, the expandable seal including two end portions, one of the two end portions engaged to the non-rotating seal member and the other of the two end portions engaged to the housing;

an internal clamp disposed within an end portion of the expandable seal such that the end portion of the expandable seal is compressed between the internal clamp and the bore of the housing; and

a second internal clamp disposed within an end portion of the expandable seal such that the end portion of the expandable seal is compressed between the second internal camp and the bore of the non-rotating seal member.

2. The rotary union of claim 1 , wherein the internal clamp is configured to compress the end portion under all operating conditions of the rotary union.

3. The rotary union of claim 1 , wherein the internal clamp is configured to compress the end portion at a variable degree depending on a fluid pressure of media within the rotary union.

4. The rotary union of claim 1 , wherein the internal clamp includes at least one arcuate wall segment and at least one resilient structure disposed between two adjacent ends of the at least one arcuate wall segment.

5. A rotary union, comprising:

a housing having a fluid inlet;

a rotating machine component rotatably supported in the housing;

a rotating seal member associated with the rotating machine component;

a non-rotating seal member slidably and sealably disposed within the housing adjacent the rotating seal member;

an expandable seal disposed between and sealably engaging a bore in each of the non-rotating seal member and the housing, the expandable seal including two end portions, one of the two end portions engaged to the non-rotating seal member and the other of the two end portions engaged to the housing; and

an internal clamp disposed within an end portion of the expandable seal such that the end portion of the expandable seal is compressed between the internal clamp and the bore of the housing;

wherein the internal clamp includes a plurality of arcuate wall segments and a plurality of resilient structures disposed, one each, between adjacent ends of two adjacent arcuate wall segments around an entire periphery of the internal clamp; and

wherein each resilient structure includes:

two leaf spring portions disposed, one each, at either axial end of the internal clamp; and

a synchronizer bar connected between the two leaf springs.

6. The rotary union of claim 5 , wherein each leaf spring portion includes two legs connected to one another at one end to an apex, and connected at each respective second end to an adjacent arcuate wall segment edge, and wherein the synchronizer bar is connected between two apices.

7. The rotary union of claim 6 , wherein the legs are disposed in a V-configuration that defines therewithin an angle, the angle being configured to increase as the internal clamp expands to increase its outer diameter.

8. The rotary union of claim 5 , wherein the internal clamp is configured to assume an over-center locked position when displaced axially.

9. A rotary union, comprising:

a housing having a fluid inlet;

a rotating machine component rotatably supported in the housing;

a rotating seal member associated with the rotating machine component;

a non-rotating seal member slidably and sealably disposed within the housing adjacent the rotating seal member;

an expandable seal disposed between and sealably engaging a bore in each of the non-rotating seal member and the housing, the expandable seal including two end portions, one of the two end portions engaged to the non-rotating seal member and the other of the two end portions engaged to the housing;

an expandable ring disposed within an end portion of the expandable seal such that the end portion of the expandable seal is compressed between the expandable ring and the bore of the housing;

a second expandable ring disposed within an end portion of the expandable seal such that the end portion of the expandable seal is compressed between the second expandable ring and the bore of the non-rotating seal member.

10. The rotary union of claim 9 , wherein each of the expandable ring and the second expandable ring is configured to compress the end portion under all operating conditions of the rotary union.

11. The rotary union of claim 9 , wherein each of the expandable ring and the second expandable ring is configured to compress the end portion at a variable degree depending on a fluid pressure of media within the rotary union.

12. The rotary union of claim 9 , wherein the expandable ring includes three arcuate wall segments and three resilient structures disposed symmetrically around a periphery of the expandable ring in alternating order.

13. The rotary union of claim 12 , wherein each resilient structure includes:

two leaf spring portions disposed, one each, at either axial end of the internal clamp; and

a synchronizer bar connected between the two leaf springs.

14. The rotary union of claim 13 , wherein each leaf spring portion includes two legs connected to one another at one end to an apex, and connected at each respective second end to an adjacent arcuate wall segment edge, and wherein the synchronizer bar is connected between two apices.

15. The rotary union of claim 14 , wherein the legs are disposed in a V-configuration that defines therewithin an angle, the angle being configured to increase as the internal clamp expands to increase its outer diameter.

16. The rotary union of claim 9 , wherein the expandable ring is configured to assume an over-center locked position when displaced axially.