Testing bubble/leak

The period between such tests will depend on the maintenance schedule for the plant, which should also include the in-situ soundness testing of non-return valves and safety shut-off valves by bubble leak detectors, etc. 

Immediately following the initial assembly (and at any other time leaks are suspected), the box and purification train should be tested for leaks. A quick test for leaks is to pressurize the dry box until the gloves stick straight out. The gloves should remain in this position for several hours if no leaks are present. If leaks are indicated, testing is most easily accomplished while the box is pressurized. If the inert atmosphere is helium, the preferred method is the helium sniff test. All joints, welds, and connections should be checked. In the absences of a helium-sensitive probe or if the inert atmosphere is other than helium, the bubble method may be used a small amount of soapy water is placed on leak-prone welds and joints and the appearance of any bubbles is noted. 

The bomb is then placed in the jacket, and the gas inlet tube is fastened securely. The thermocouple is also inserted. From this point on, all operations should be performed on the other side of the wall separating the operator from the equipment. Hydrogen is bled into the bomb from the high-pressure tank, the valve to the tank is closed, and the bomb is allowed to stand for about a half hour in order to test for leaks. If a leak has developed, as indicated by a drop in pressure, one locates it by painting all the joints with a soap solution and looking for bubbles of gas, which indicate a leak. The connector is tightened, and if this does not stop the leak, the pressure in the system should be released, the connection disassembled, and the tapered end of the tube re-formed with a tool supplied for the purpose. These measures usually will stop the leak, but if they do not, it will be necessary to ream out the connector seat with the reamer designed for this purpose. 

Hydrotest Pneumatic Test Soap Bubble Test Helium Leak Test Performance Test Acoustic Emission Test Hardness Test Ferrite Check Copper Sulfate Test PMI... 

Bubble/leak testing—utilizing high molecular weight fluorocarbons (tradename Fluorinerts )... 

Piping required to have a sensitive leak test shall be tested by the gas- and bubble-formation testing method specified in Art. 10, Sec. V of the ASME Code or by another method demonstrated to have equal or greater sensitivity. The sensitivity of the test shall be at least (100 Pa mL)/s [(10 atm mL)/s] under test conditions. If a hydrostatic pressure test is used, it shall be carried out after the sensitive leak test. 

Immediately after the running test, any compressor intended for toxic, hazardous, flammable, or hydrogen-rich service should be gas tested with an inert gas to the maximum seal design pressure. The test is held at least 30 minutes and the casing and its joints checked for leaks, using a soap bubble method or other suitable means for leak detection. When no leaks are detected, the compressor will be considered acceptable. 

VII-3.6.2 Procedure. The exposed piping systems shall be reasonably cleaned and completely coated with the solution. Leaks are indicated by the presence of bubbles. The bubble-forming solution shall not be used on piping unless it has been determined by investigation or test that the piping is adequately resistant to direct contact with the solution. 

Test methods described in the literature inelude the bubble method, helium mass speetrometiy, liquid tracer (dye), head spaee analysis, vacuum and pressure decay, weight loss and gain, and high voltage leak deteetion [6]. 

Table 5.3 Comparison of bubble test method (immersion technique) wit helium leak...

Pressure Test The performance of the LC pump depends on the proper functioning of the pump seal, check valves, and proper connection of the tubing. Properly functioning pump seal check valves and tubing connections are important in maintaining stable mobile-phase flow and system pressure. For pump systems that output the pressure reading in the pump head over time, a simple pressure test can be a useful qualitative test to check the performance of the seals and check valves and to determine whether or not there are any leaks in the system [9]. When performing the pump pressure test, make sure that the system is well primed so that no bubbles are present in the pump system. The pressure fluctuation caused by the presence of air bubbles in the pump will lead to misinterpretation of the test results. 

Figure 11. Mechanical stress-strain behavior of four strips cut from a cell after a RH cycling test of 50 cycles from 0-100% RH the blue spots marked on the MEA are leaking locations identified by a bubble test after the RH cycling the insert shows the fracture location ofeach strip.

Leak pressure The value of increasing inlet static pressure at which the first bubble occurs when an SRV is tested by means of air under the valve disc and a specified water seal on the outlet. 

Process Put three or four lumps of charcoal in the combus ion tube and connect the different parts of the apparatus. Regulate the flow of carbon dioxide so that the rate is (approximately) a bubble a second. Stop the leaks, if any are detected. Heat the whole combustion tube at first, and finally concentrate the heat where the charcoal is located. Collect all the gas evolved, but reject the first two bottles, as they contain air (and possibly carbon dioxide). Collect two or three more bottles, cover with glass plates, and set them aside temporarily. Stop the generator, remove the delivery tube from the trough, and gradually cool the combustion tube. Test the gas thus —... 

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