# US 2010/0166537 A1 · Inspection hole plug with a ball swivel > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0166537 A1 - Document ID: US20100166537A1 - Status: Published application - Kind: A1 - Application number: 12/318,401 - Filed: 2008-12-29 - Published: 2010-07-01 - Earliest claimed: 2008-12-29 - Assignees: Caterpillar Inc. - Inventors: David B. Walker; Christopher J. Meyer; Tsuhon Lin - Web page: https://patentgrep.com/patent/US20100166537A1 ## CPC - F01D 25/24: Casings (modified for heating or cooling F01D25/14); Casing parts, e.g. diaphragms, casing fastenings (casings for rotary machines or engines in general F16M {; special arrangements in stators dealing with breaking-off of part of rotor F01D21/045}) - F05D 2260/80: Diagnostics - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A plug for an inspection hole of a gas turbine engine is disclosed. The plug may have a stem including a first shaft, wherein a first seal is located circumferentially about the first shaft. The plug may have a swivel seal including a second seal spaced from a ball by a second shaft, and the swivel seal may be rotatably connected to the stem by the ball. The ball and the second seal may be fixed to the second shaft. ## Claims ### Claim 1 A plug for an inspection hole of a gas turbine engine, comprising; a stem including a first shaft, wherein a first seal is located circumferentially about the first shaft; a swivel seal including a second seal spaced from a ball by a second shaft, wherein the swivel seal is rotatably connected to the stem by the ball, and the ball and the second seal are fixed to the second shaft. ### Claim 2 (depends on 1) The plug of claim 1, wherein the first seal is formed integrally with the stem. ### Claim 3 (depends on 1) The plug of claim 1, wherein the second seal is tear-drop shaped. ### Claim 4 (depends on 1) The plug of claim 1, further including a cover connected to a first end of the stem and the ball is rotatably secured within the cover. ### Claim 5 (depends on 4) The plug of claim 4, wherein the cover restricts rotational movement of the swivel seal relative to the stem by a predetermined angle. ### Claim 6 (depends on 5) The plug of claim 5, wherein the predetermined angle is within a range of about 4 to about 12 degrees. ### Claim 7 (depends on 5) The plug of claim 5, wherein the predetermined angle is about 6 degrees. ### Claim 8 (depends on 1) The plug of claim 1, wherein the stem includes a stem seal positioned between a first stem portion and a second stem portion. ### Claim 9 (depends on 1) The plug of claim 1, further including a cap, and wherein a second end of the stem movably engages the cap. ### Claim 10 (depends on 9) The plug of claim 9, wherein the cap includes a recess and the second end of the stem moveably engages the cap along an axial direction within the recess. ### Claim 11 (depends on 1) The plug of claim 1, wherein the stem includes a chamfered collar adjacent the first seal. ### Claim 12 (depends on 1) The plug of claim 1, wherein the swivel seal includes a collar positioned on the second shaft and between the second seal and the ball, the collar having a maximum diameter that is larger than the maximum diameter of the second seal. ### Claim 13 A method of restricting a flow of gas through an inspection hole of a gas turbine engine with a plug, comprising: restricting the flow of gas through a first inner wall of the gas turbine engine with a first seal of the plug; restricting the flow of gas through a second inner wall of the gas turbine engine with a second seal of the plug; covering the inspection hole at an outer wall of the gas turbine with a cap; permitting rotation of the first seal relative to the second seal about only a single pivot point; and limiting an amount of rotation of the first seal relative to the second seal by a predetermined angle. ### Claim 14 (depends on 13) The method of claim 13, wherein the inspection hole is oriented along an axis that is misaligned from the directional force of gravity, and further including inserting the plug within the inspection hole substantially along the axis. ### Claim 15 (depends on 13) The method of claim 13, wherein the predetermined angle includes a range of about 4 degrees to about 12 degrees from the axis of the inspection hole. ### Claim 16 (depends on 13) The method of claim 13, further including pressurizing gases in a first zone between the outer wall and the second wall to a higher pressure than gases in a second zone between the first wall and the second wall so that the higher pressure gases of the first zone urge the plug towards the second zone. ### Claim 17 (depends on 16) The method of claim 16, wherein restricting the flow of gas through the first inner wall with the first seal includes permitting the first seal to move substantially in an axial direction while maintaining the seal between the first inner wall and the first seal. ### Claim 18 (depends on 16) The method of claim 16, wherein restricting the flow of gas through the second inner wall includes permitting the second seal to move substantially in an axial direction while maintaining the seal between the second inner wall and the second seal. ### Claim 19 A gas turbine engine, comprising: an outer wall spaced from a first inner wall and a second inner wall; an inspection hole passing through the outer wall, the first inner wall, and the second inner wall, wherein the first inner wall includes a first bore and the second inner wall includes a second bore; a plug inserted within the inspection hole, the plug comprising: a stem including a first end and a second end, a first wall seal located on the stem adjacent the first end and configured to seal the first bore; a swivel seal including a second wall seal connected to a ball by a shaft, wherein the swivel seal is pivotally connected to the first end of the stem by the ball, and the second wall seal is non-rotatably attached to the shaft; a cover housing the ball and configured to limit rotation of the swivel seal relative to the stem; and a cap removably attached to the outer wall to cover the inspection hole. ### Claim 20 (depends on 19) The gas turbine engine of claim 19, further including a shroud located between the first inner wall and the outer wall, the inspection hole passing through a shroud bore within the shroud; and a stem seal is moveably connected to the stem to substantially seal the shroud bore.