Local Pressure Testing Jig for Welded Casing Joints
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Solution Overview
Problem
Performing a pressure test on the welded portion between an additional member and a large casing, such as a compressor, is wasteful in terms of cost and workload when the additional member is small relative to the casing, necessitating an efficient method for localized testing.
Innovation Solution
A local pressure testing jig and method that includes a supply pipe, discharge pipe, valves, and a detachable retaining portion to perform a hydraulic test on the welded portion by supplying and sealing liquid to the through-hole and casing hole, using a pressure measurement portion to ensure the pressure exceeds a predetermined threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure test is performed on the entire casing to ensure the welded portion is reliable, then the reliability of the welded portion is improved, but the cost and workload increase significantly
Solution Approach 1:
The patent divides the pressure testing process into two segments: a local pressure test on the welded portion and a full pressure test on the entire casing. The local test uses a testing jig that isolates and pressurizes only the welded area between the additional member and casing, while the full test covers the entire casing. This segmentation allows the reliability of the welded portion to be verified efficiently without requiring the entire casing to be tested, thus reducing cost and workload while maintaining confidence in the weld quality.
2Reliability
If a full pressure test is performed on the entire casing, then the reliability of the entire system is improved, but the time required for testing increases
Solution Approach 1:
The patent applies preliminary action by first performing a local pressure test on the welded portion before conducting a full pressure test on the entire casing. The testing jig is installed on the additional member, and liquid is supplied to pressurize only the welded area, allowing defects in the weld to be detected early. This preliminary localized test reduces the time required for subsequent full testing, as the welded portion is already verified to be sound, thereby reducing overall testing time while maintaining system reliability.
3Productivity
If a local pressure test is performed only on the welded portion, then the testing cost and workload are reduced, but the reliability verification becomes insufficient
Solution Approach 1:
The patent segments the verification process into two distinct stages: first, a local pressure test on the welded portion using a specialized testing jig that isolates and pressurizes only the weld area; second, a full pressure test on the entire casing. This segmentation ensures that the welded portion receives targeted verification with appropriate pressure application, while the full test confirms the integrity of the entire casing. Together, these segmented tests provide sufficient reliability verification without the excessive cost and workload of testing the entire system from the outset.
4Ease of operation
If a testing jig with multiple components is used for local pressure testing, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The testing jig is designed with multi-functionality to simplify operation while managing complexity. The jig includes a body with a through-hole that receives an insertion pipe, a closing portion that seals the casing hole, and a detachable retaining portion that secures the insertion pipe. The same jig structure handles both the local pressure test and the full pressure test by simply removing and reinstalling the testing jig on the additional member. This universal design allows one device to perform multiple testing functions, improving ease of operation while keeping the overall system manageable.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and localized pressure testing on the welded portion without requiring a full-scale test of the entire compressor, reducing costs and workload by allowing testing at the installation site.
Implementation Method 1
supplying liquid to an additional member having a tubular shape that is fixed to the casing by the welded portion... capable of measuring a pressure inside the supply pipe, the discharge pipe, or the insertion pipe
Data Source
AI summary
A local pressure testing jig includes: a supply pipe capable of supplying a liquid; a discharge pipe capable of discharging the liquid; a supply valve capable of adjusting a supply amount of the liquid; a discharge valve capable of adjusting a discharge amount of the liquid; an insertion pipe capable of being inserted into a through-hole and a casing hole; a detachable retaining portion detachably fixed to the additional member in a state in which the through-hole is closed; a closing portion closing the casing hole at a leading end of the insertion pipe; a sealing portion sealing between the closing portion and the casing hole; and a pressure measurement portion capable of measuring an internal pressure. The insertion pipe is formed to have a smaller diameter than the through-hole, and includes a supply hole, opening in the through-hole and capable of communicating with a space between the through-hole and the insertion pipe.