Troubleshooting recording problems

Using this or similar mixtures, inject a sample into an equilibrated column, elute the resolved bands, and record them on the recorder. Calculate plate counts for the first and last peak using the 5 [Pg.38]

Figuring out how to record on your computer is not always easy. The combination of hardware, drivers, and software level interface makes troubleshooting a less than intuitive task. And while it is fairly straightforward to isolate output problems, since you can hear whether your card is working or not, input and recording problems cannot always be fixed by ear. To simplify this procedure and avoid crashes, it is best to close other applications while working through this process.

Maintenance and production records, along with the used lean and rich glycol analyses, can be very helpful to the troubleshooter. A history of filter element, carbon, tower packing, and firetube changeouts can sometimes be very revealing. The frequency of pump repairs and chemical cleaning jobs is also beneficial. With this type of knowledge, the troubleshooter can quickly eliminate and prevent costly problems. 

The HPLC user should know or learn what to look for and what to do to prevent HPLC problems and, finally, what can and should be done before calling a service technician. User s manuals, manufacturer s advice, books, articles in scientific journals, computer programs, and network sites can be used as resources for troubleshooting. A general rule is that one can know that a problem exists only when one knows how the system operates when it is working well. This means that keeping detailed records of system performance (log book) is very helpful. 

Records also help prevent mistakes, such as introducing water into a silica column, or precipitating buffer in the system by adding too much organic solvent. Many analysts occasionally modify their HPLC systems for a variety of reasons. Reliable records are the best way to ensure that a modification does not introduce problems. For problems relating to pumps, detectors, automatic samplers, and data systems, instrument manuals provide suitable troubleshooting guides. 

Although complete and contemporaneous documentation of study events is critical from a regulatory perspective, it should not be viewed solely as a regulatory requirement. It is also essential to the bioanalytical laboratory in its effort to demonstrate that a method is reliable and can produce high-quality data. Furthermore, comprehensive recording of study events can assist the bioanalytical laboratory in troubleshooting efforts, when unexpected problems occur during routine sample analysis. 

The third type of risk is to do with what is referred to as RAM. This topic, which is discussed in detail in Chapter 20, is related to troubleshooting but implies a higher degree of predictability. Based on historical records, the failure rates and repair times of equipment items can be predicted and maintenance schedules can be set up so as to preemptively address potential problems. Management systems such as Risk-Based Maintenance and Risk-Based Inspection are often integrated with the RAM program. Investments in availability improvement programs are often very attractive because such investments have a disproportionate effect on profitability. 

Troubleshooting procedures are organic. As more and more operating experience is gained from the facility, so the amount of useful troubleshooting material will increase. Their usefulness depends on the commitment that facility personnel make toward recording their experiences whenever a problem arises. 

Data acquisition systems are extremely useful in extrusion because problems often occur when the operator is not watching the instrument panel of the extruder. Even if the operator is watching the instrument panel, he can only observe a limited number of variables at one time. A DAS that captures and saves important process data is indispensable in troubleshooting. When a problem occurs at 2 30 AM, it is very difficult for a process engineer coming in at 7 00 AM to reconstruct the events at 2 30 AM if important process data was not recorded at that particular time. 

Troubleshooting models are literal, physical demonstrations of the equipment and systems presently being taught in community colleges and universities. Some of these models are the reaction model, the absorption and stripping model, the separation model, and the distillation model. These models are completely outfitted with alarms, analyzers, interlocks, permissives, video trends, recorders, and control instrumentation. Process problems can be simulated using these models. 

In retrospect, it may seem ludicrous to have cut back production because of a limited range on an unimportant flow recorder. Both the problem and solution seem to be the sort of thing local supervision should have handled. Perhaps troubleshooting of this type is too trivial for the trained chemical engineer. 

The capacity limit of this sulfur plant was, in a sense, not due to the small range of the flow recorder. A communications breakdown between the unit operators and first-line supervision had resulted in an artificial limitation. The troubleshooting engineer is most effective when he overcomes this failure to communicate. This is best done by personally gathering data, making direct field observations, and most importantly, soliciting the opinions of the shift operators. This type of activity, when joined with sound technical training, makes a powerful combination with which to tackle refinery problems. 

Some of the instruments only indicate or record the process variable and have no control function whatsoever. Other instruments, called controllers, are the nerve center of the process unit. The operating engineer troubleshooting a process problem should locate all of the controllers on the panel board. Those controllers will have the following features. 

Calibrating pressure of flow indicators is a job for the instrument mechanic. The operating engineer will, however, frequently need to zero instruments, especially flow recorders. This is a necessary first step in running a performance test or troubleshooting a material balance problem, and that is done as follows ... 

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