RING CHANGE TOOLING AND METHODS

1 . An apparatus comprising:

at least one element configured to interface to an end of a cylinder; and

a plurality of retainers configured to constrain a sealing ring assembly, wherein:

in a first configuration, at least one retainer of the plurality of retainers constrains at least one segment of the sealing ring assembly in a groove of a piston; and

in a second configuration, the at least one retainer of the plurality of retainers is axially offset from at least one segment such that the at least one segment is radially removeable.

2 . The apparatus of claim 1 , further comprising a flange extending radially inward from the at least one element to partially obstruct a bore of the cylinder to constrain axial displacement of the piston into the bore of the cylinder, wherein the flange is configured to block the piston from moving into the bore.

3 . The apparatus of claim 1 , wherein the at least one element comprises at least two azimuthal segments.

4 . The apparatus of claim 1 , wherein the sealing ring assembly is arranged in a groove of the piston and is configured to seal against both a land of the piston and a bore of the cylinder, and wherein the at least one element further comprises at least one mounting feature configured to be engaged with the cylinder.

5 . The apparatus of claim 1 , wherein:

each respective retainer comprises a respective first feature; and

the at least one element comprises a plurality of second features, wherein the apparatus further comprises a plurality of tethers that couple each respective first feature to a respective second feature of the plurality of second features such that each respective retainer is tethered to the at least one element.

6 . The apparatus of claim 1 , wherein:

the plurality of retainers each comprise a respective head and a respective pin;

the at least one element comprises a plurality of axial holes;

each respective pin is configured to move axially in a respective axial hole of the plurality of axial holes; and

each respective head is configured to contact the sealing ring assembly to prevent radial displacement of one or more segments of the sealing ring assembly.

7 . The apparatus of claim 6 , wherein each retainer of the plurality of retainers is axially biased by a spring.

8 . The apparatus of claim 1 , wherein the plurality of retainers each comprise a respective disc configured to contact the sealing ring assembly to prevent radial displacement of one or more segments of the sealing ring assembly.

9 . The apparatus of claim 1 , wherein the plurality of retainers each comprise a respective asymmetric washer configured to:

achieve a first angular orientation and a second angular orientation;

at the first angular orientation, prevent radial displacement of one or more segments of the sealing ring assembly; and

at the second angular orientation, allow radial displacement of the one or more segments of the sealing ring assembly.

10 . The apparatus of claim 1 , wherein:

the plurality of retainers each comprise a respective head and at least two respective pins;

each respective head comprises a respective radial width and a respective azimuthal length; and

the respective radial width is less than the respective azimuthal length.

11 . An apparatus comprising:

a first element configured to engage with a first ring segment of a sealing ring assembly to form a first subassembly; and

a second element configured to engage with the first element and to engage with a second ring segment of the sealing ring assembly to form a second subassembly, wherein:

the first and the second subassemblies are configured to be engaged with each other and arranged azimuthally around a groove of a piston, and

the first and second element are configured to be removed before operation.

12 . The apparatus of claim 11 , wherein:

the first element comprises at least one first feature configured to be engaged with a mating feature of the first segment; and

the second element comprises at least one second feature configured to be engaged with a mating feature of the second segment.

13 . The apparatus of claim 11 , wherein:

the first element comprises at least one first mounting feature configured to be engaged with the piston; and

the second element comprises at least one second mounting feature configured to be engaged with the piston.

14 . The apparatus of claim 11 , further comprising at least one retainer configured to interface with the first segment and with the first segment to retain the first segment and the first element together in at least one degree of freedom.

15 . A method for servicing a sealing ring assembly that seals against a piston and a cylinder of a linear generator, the method comprising:

engaging a respective segment of the sealing ring assembly to a respective element of a plurality of elements of a ring tool;

configuring the plurality of elements such that the sealing ring assembly is arranged in a groove of piston; and

positioning the piston such that the sealing ring assembly is laterally bound by one or more of the cylinder or the ring tool to retain the rings in place in the groove of the piston.

16 . The method of claim 15 , further comprising blocking the piston from entering the cylinder using a flange.

17 . The method of claim 15 , further comprising removing the ring tool after positioning the piston.

18 . A method for servicing a sealing ring assembly that seals against a piston and a cylinder of a linear generator, the method comprising:

arranging a ring tool at an axial end of the cylinder;

positioning the piston such that the sealing ring assembly is axially proximal to the ring tool;

constraining at least one segment of the sealing ring assembly using a plurality of retainers of the ring tool; and

actuating one or more retainers of the plurality of retainers to allow radial displacement of the at least one segment.

19 . The method of claim 18 , further comprising installing a ring sleeve to retain the sealing ring assembly during the positioning of the piston, wherein arranging the ring tool at the axial end of the cylinder is performed after installing the ring sleeve.

20 . The method of claim 18 , wherein constraining the at least one segment using the plurality of retainers comprises achieving a first respective axial position of each respective retainer of the plurality of retainers, and wherein actuating the one or more retainers of the plurality of retainers to allow radial displacement of the at least one segment comprises achieving a second respective axial position of each respective retainer of the plurality of retainers.

21 . The method of claim 20 , further comprising maintaining at least one retainer exclusive of the plurality of retainers to constrain another segment of the sealing ring assembly exclusive of the at least one segment.

22 . A method for servicing a sealing ring assembly that seals against a piston and a cylinder of a linear generator, the method comprising:

positioning the piston into a ring change position such that the piston is outside of the cylinder;

constraining the ring assembly with a sleeve to block radial displacement of the ring assembly;

attaching a ring tool having one or more ring retainers at an axial end of the cylinder such that the one or more ring retainers contact an outer radial surface of the ring assembly;

removing the sleeve off of the ring assembly;

depressing the ring retainers such that they move off of the ring assembly; and

removing the ring assembly.

23 . The method of claim 22 further comprising:

depressing the ring retainers to allow space for the ring assembly to be incrementally inserted;

incrementally inserting the ring assembly into a ring groove of the piston while releasing the ring retainers to capture the ring assembly in the ring groove;

constraining the ring assembly with a sleeve to block radial displacement of the ring assembly;

removing the ring tool from the piston;

translating the piston partially into the cylinder such that the cylinder inhibits radial displacement of the ring assembly from an initial installation position; and

removing the sleeve.

24 . The method of claim 22 , wherein the step of positioning the piston into the ring change position is accomplished by a control system causing positioning via stator-translator interaction.

25 . A device for servicing a sealing ring of a piston comprising:

a first element configured to engage with a first ring segment of a sealing ring assembly; and

a second element configured to engage with the first element and to engage with a second ring segment of the sealing ring assembly, wherein:

the first and the second elements are configured to be engaged with each other and arranged azimuthally around a groove of a piston to constrain the sealing ring assembly when positioned axially outside of a bore of a cylinder.

26 . The device of claim 25 , further comprising a flange configured to block the piston from entering the cylinder.

27 . The device of claim 25 , wherein the device is configured to be removed from the piston after the piston is positioned relative to the cylinder.

28 . The device of claim 25 , wherein:

the device is configured to interface with a ring sleeve to retain one or more of the first segment or the second segment during positioning of the piston; and

the device is configured to be arranged at the axial end of the cylinder after the ring sleeve is installed.

29 . The device of claim 25 , further comprising a plurality of retainer configured to constrain one or more of the first segment or the second segment.

30 . The device of claim 29 , wherein one or more of the plurality of retainers allow radial displacement of one or more of the first segment or the second segment.