Leak problem

Initially, the as-received pump could not pass a 13.8-bar (200 psig) static pressure test at ambient temperature. Consequently, the pump was returned to the manufacturer for extensive seal modifications. Upon receiving the modified pump, the unit was placed into service for a hot shakedown test with C30 oil at 175 psig pressure under the present experimental setup. The modified seal continued to leak at a small but acceptable rate on the order of 1 g/min. However, leak problems were encountered in the threaded seal of the stator and the pump housing. The stator was resealed with a thick Teflon tape and a high-temperature pipe sealant that initially slowed the total system leaks to less than 50 g/h. 

No magnesium sulfate was added to the system for run MG-3. The objective of this run was to evaluate the system performance with decreasing Mg2+ concentration. The mass balance indicated that the total Mg2 concentration should drift down to below 500 ppm. During the run, the total Mg2+ concentration decreased from 1000 ppm to about 625 ppm toward its end. A leak was discovered at the scrubber bleed/quench recirculation pump inlet which introduced air into the process stream and therefore caused high oxidation. The high oxidation, as confirmed by solids analysis results in Table 3, was reflected by increases of the sulfate-to-sulfite ratio to above 2.5. After the air leak problem was corrected, the sulfate-to-sulfite ratio decreased, but the test average was 2.4. 

Basically, start with a more flexible system, develop a design that works to your satisfaction, then review the connections to see where potential leak problems can be eliminated with pipe bending or welding, or other means. This is important if your goal is a safer, low maintenance system. 

A pipe nipple without threads and with a weld-on flange would be a more permanent fixture. Also, the screw-on flanges can be welded on, though it would be best to use weld-on flanges if you are going that route. Weld-on flanges will reduce leak problems, and the pipe nipple wall structure would not be weakened by threading. 

Generally, it should be found out if the dead time to has changed (this indicates a pump or leak problem) or if the k values are different (this indicates a solvent or temperature problem). 

Obtain a clear, factual definition of the symptoms. A poor definition of symptoms is one of the most common troubleshooting pit-falls. In the debutanizer case history above, the following definitions were used by different people to describe the symptoms of a reboiler tube leak problem ... 

Full-face masks (Fig. 6.28) include protection of the eyes, as they completely enclose the face. They are excellently suitable for use with ambient air-indep>en-dent respiratory devices. Because the sealing line runs from the forehead, over the cheeks, and down below the chin, leak problems may occur with persons with a beard. This could be a prohibiting factor for this group of persons. The... 

This can have a fundamental effect on the thermal efficiency of the factory calling for thicker insulation, return mains, increased costs of leaks, problems with flash steam, etc. 

Some distillation columns with partial condensers are constructed with the condenser installed at the top of the column inside the shell. There is usually no reflux drum. Vapor flows upward through the tubes of the condenser. The condensate liquid flows downward and drops into a liquid distributor above the top tray. These dephlegmatoi systems are frequently used when very toxic or dangerous chemicals are involved because it avoids potential leak problems with pumps and extra vessels and fittings. 

In response to the hydrogen leak problems, development has been ongoing to improve propellant... 

Overall, the Southeastern Community survey revealed high level of awareness of panhole leak problem among residents of the community. Twenty percent of the households reported actual pinhole leak incidents. The percent of pinhole leak reports was on par with other hotspot areas of corrosion in the U.S., but above the rate of pinhole leak occurrences in non-hotspots (Scardina et al., 2007). The pinhole leak problem was more prevalent in houses built before the 1990s with copper papes installed as the plumbing system. This finding is in an agreement with a Maryland Pinhole Leak Survey conducted by Kleczyk and Bosch in 2004. 

From the results of two independent experiments, the leak rate was calculated to be less than 1.4 nl/min in a perfectly functioning valve. This results in a leak ratio of 1 1000 for a system flow of 1 pl/min in a micro-TAS, and such a leak ratio is not expected to cause measurement problems. But if one particle of 1 pm in diameter is trapped on the valve seat and prevents closing of the valve, a slit with an expected width of 100pm, will occur and result in a leak rate of about 5 nl/min. In a system with a flow rate of 1 pl/min, a leak rate of 5 nl/min may add an error to the chemical signal. To prevent leak problems in future micro-TAS, particle filtration and well-designed valve seats should be included in the design of the system. 

The other major design consideration in transfer systems again involves minimization of the heat inleak to the transfer fluid. Solutions to this specific heat-leak problem are similar to those noted for conventional dewars. 

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