Purging for welding
AssigneeSaudi Arabian Oil Company
InventorTariq Abdulwahed Ali Alghamdi
Life of this patent
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Abstract
A system and method of purge testing for welding piping, including flowing a purge gas through a test pipe, determining concentration of a gas component in the purge gas discharged from the test pipe, and determining a time period to reach a lower threshold of the concentration. The testing may consider different flow rates, pipe sizes, and inlet/outlet bore sizes.
Claims24
A system for purge testing to determine pre-welding purge time for piping to be welded, the system comprising:
- a test pipe comprising a same diameter of the piping to be welded;
- a plurality of pipe end closures to fit on an inlet end of the test pipe and on an outlet end of the test pipe, each pipe end enclosure comprising a bore, wherein the plurality of pipe end closures comprises a range of bore sizes;
- an inlet conduit to fluidically couple a gas source to an inlet bore of an inlet pipe-end enclosure disposed on an inlet end of the test pipe, wherein the gas source to discharge purge gas through the inlet conduit and the test pipe;
- a gas analyzer to measure a concentration of a gas component in the purge gas discharged from the test pipe through an outlet bore of an outlet pipe-end enclosure disposed on an outlet end of the test pipe;
- a flow regulator to control a flow rate of the purge gas;
- a timing device to measure a cumulative time of the flow of the purge gas through the test pipe;
- and
- a validation test pipe that is at least three times longer than the test pipe to perform a validation test to validate a test performed with the test pipe, wherein the validation test pipe and the test pipe comprise a same diameter.
A method of purge testing with test piping to determine pre-welding purge time for piping to be welded, comprising:
- selecting a test pipe from a plurality of test pipes comprising a range of diameters, wherein the test pipe selected comprises a same diameter as the piping to be welded;
- flowing a purge gas at a specified flow rate through the test pipe to decrease concentration of a gas component in the test pipe;
- determining the concentration of the gas component in the purge gas discharged from the test pipe;
- determining a time period of the flowing of the purge gas through the test pipe to reach a lower threshold of the concentration, wherein the specified flow rate comprises multiple specified flow rates for multiple respective tests, and wherein the time period comprises multiple respective time periods to reach the lower threshold for the multiple respective tests;
- and
- specifying the pre-welding purge time for the piping to be welded correlative with a smallest time period of the multiple respective time periods.
A method of purge-time testing to determine pre-welding purge time for welding alloy piping, comprising:
- performing multiple purge-time tests comprising adjusting a first variable comprising diameter of a test pipe, a second variable comprising bore size of pipe end closures installed on each end of the test pipe, and a third variable comprising flow rate of a purge gas through the test pipe and the pipe end closures, wherein performing each test of the multiple purge-time tests further comprises:
- measuring concentration of a gas component in the purge gas discharged from the test pipe;
- and
- measuring a time period for the concentration to drop to a threshold concentration;
- and
- determining a pre-welding purge time for welding alloy piping correlative with a shortest time period in the multiple-purge time tests for the concentration to drop to a threshold concentration with the diameter of the test pipe comprising a diameter of the alloy piping.
A method of performing multiple tests with test piping to determine pre-welding purge time for piping to be welded, comprising:
- flowing a purge gas at a respective flow rate through a test pipe for each test of the multiple tests, the test pipe comprising a same diameter as the piping to be welded, wherein the test pipe is shorter in length than the piping to be welded;
- determining a concentration of a gas component in the purge gas discharged from the test pipe for each test;
- determining a respective time period to reach a lower threshold of the concentration for each test;
- and
- specifying a pre-welding purge time and purge-gas flow rate for the welding of the piping to be welded correlative with a shortest time period of the respective time periods.
Dependencies are inferred from the claim text.