Troubleshooting elements

The need for weU-trained technical service professionals is expected to continue as an essential aspect of the chemical industry, despite the phenomenal growth ia electronic methods of information storage, retrieval, and transmission. Advanced troubleshooting of complex customer processes and accelerated accurate product development and market introductions should continue to be principal elements of technical service personnel duties. Increased levels of integration, perhaps blurring the lines between suppHer and customer, may come to pass. There are already instances of personnel swapping between customers and suppHers for extended periods to allow cross-fertilization of ideas and provide more accurate perspectives for the companies involved in these efforts. Technical service and research personnel have been those persons most directly involved in such efforts. 

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. 

Analytical techniques used in troubleshooting and formulation experimentation available to the rubber compounder were reviewed [90]. Various textbooks deal with the analysis of rubber and rubber-like polymers [10,38,91]. Forrest [38] has illustrated the use of wet chemistry, spectroscopic, chromatographic, thermal, elemental and microscopy techniques in rubber analysis. 

Applications X-ray fluorescence is widely used for direct examination of polymeric materials (analysis of additives, catalyst residues, etc.) from research to recycling, through production and quality control, to troubleshooting. Many problems meet the concentration range in which conventional XRF is strong, namely from ppm upwards. Table 8.42 is merely indicative of the presence of certain additive classes corresponding to elemental analysis element combinations are obviously more specific for a given additive. It should be considered that some 60 atomic elements may be found in polymeric formulations. The XRF technique does not provide any structural information about the analytes detected the technique also has limited utility when... 

Experience with CE method transfer in the biotech/pharmaceutical industry over the past 10—20 years has demonstrated that training is a key element that requires special attention for CE methods. A training video with troubleshooting examples can be very useful. Tips and hints should also be shared during the method transfer process. Other key elements for a successful transfer include selection of the proper testing strategy and assay acceptance criteria. 

Finally, process analytics methods can be used in commercial manufacturing, either as temporary methods for gaining process information or troubleshooting, or as permanent installations for process monitoring and control. The scope of these applications is often more narrowly defined than those in development scenarios. It will be most relevant for manufacturing operations to maintain process robustness and/or reduce variability. Whereas the scientific scope is typically much more limited in permanent installations in production, the practical implementation aspects are typically much more complex than in an R D environment. The elements of safety, convenience, reliability, validation and maintenance are of equal importance for the success of the application in a permanent installation. Some typical attributes of process analytics applications and how they are applied differently in R D and manufacturing are listed in Table 2.1. 

The results of the 4D-QSAR case study are interesting and provide large amounts of data about the system of interest, and, unlike static 3D-QSAR methods (CoMFA and SOMFA), 4D-QSAR is able to provide the exact locations of statistically important interaction pharmacophore elements. The ability of this method to overcome the question of What conformation to use and predict the bioactive conformation is impressive and a major reason to use the software. Yet it is the ability to construct manifold models and examine several models for the same alignment that is the true benefit of this method. Add to the list the ability to determine the best alignment scheme (based on statistical and experimental results) and this method will provide more information than one could imagine. This abundance of information is key when troubleshooting results that are not in agreement with current beliefs. 

One of the elements of film coating that attracts much attention at technical symposia is that dealing with troubleshooting. This very fact is a clear indication of how poorly the matters described here are considered. While it is certainly important to understand the issues that can potentially lead to problems, and explore recovery options, the very idea that troubleshooting needs to be considered is clearly an admission of failure during... 

One last point needs to be made in this brief introduction to troubleshooting you should document your work. If the process of elimination or the process of questioning the user goes beyond two or three crucial elements, start writing it... 

The two most common RO membrane configurations used in water treatment today are spiral-wound and hollow fiber. The spiral-wound elements can operate at a higher pressure and at a higher silt density index (SDI) than the hollow fiber type, and thus may require less pretreatment (and are more tolerant of pretreatment upsets). They also are easier to clean than the hollow fiber type. The main advantage of the hollow fiber configuration is that it has the highest amount of membrane area per unit volume, thus requiring less space. Since there is only one hollow fiber element per pressure vessel, it is easier to troubleshoot, and it is easier to replace membrane modules. 

To apply control to a process, one measures the controlled variable and compares it to the setpoint and, based on this comparison, typically uses the actuator to make adjustments to the flow rate of the manipulated variable. The industrial practice of process control is highly dependent upon the performance of the actuator system (final control element) and the sensor system as well as the controller. If either the final control element or the sensor is not performing satisfactorily, it can drastically affect control performance regardless of controller action. Each of these systems (i.e., the actuator, sensor, and controller) is made up of several separate components therefore, the improper design or application of these components, or an electrical or mechanical failure of one of them, can seriously affect the resulting performance of the entire control loop. The present description of these devices focuses on their control-relevant aspects. Later, troubleshooting approaches and control loop component failure modes are discussed. 

The key to effective troubleshooting is expressed in the old adage, divide and conquer. It is important to locate the portion of the control loop hardware that is causing the poor performance the hnal control element, the sensor system, the controller, or the process. The place to start is to test each system separately to determine whether that portion of the control loop is operating properly. The hnal control element can be evalnated by applying a series of input step tests. That is, the input to the hnal control element, which is normally set by the controller, can be manually adjusted. The test allows the determination of the dynamic response and deadband of the actuator system. If the performance in these two areas is satisfactory, there is no need to evaluate the actuator system further. 

Figure 13.15 shows the operational scheme of this automatic tltrator. The heart of the unit Is an INTEL 8080 microprocessor mounted on the central processing unit (CPU) board. The rotary reaction cell assembly can accommodate up to three different sensors for multiple measurements on the same processed sample. Each stepper burette board controls up to two burette dispensing assemblies. Function boards such as the colorimeter board, air burette board, E/I output board and RS-232 printer Interface boards are available optionally. The optional D/A and E/I board is used for closed-loop applications where the tltrator controls the final element such as a control valve. The RS-232 printer Interface board Is useful for troubleshooting the equipment and editing user-defined programs. The Instrument accuracy, repeatability and response time vary widely and depend on the particular type of measurement concerned. The system requires a.c. power, a 75-psl air supply and a dilution water supply for proper operation. The air flow-rate required is of about 50 cm3/mln... 

Some of the distinctive elements of troubleshooting procedures, and the manner in which they differ from normal operating procedures and from emergency procedures are described below. 

There is an element of creativity in troubleshooting. When solving problems, an operator will often reason by analogy, i.e., he compares the present situation with a similar, but not identical, situation that occurred at some other time and place. He then has to decide if the analogy is appropriate, and what action should be taken as a result of this reasoning. There is no place for this type of approach in the emergency response procedures. 

Troubleshooting is often the most critical element of extrusion engineering because of the huge financial impact that extrusion problems can have. As a result, this topic may be the most important in the whole book. For that reason it was decided to devote a separate publication to this subject. The book Troubleshooting the Extrusion Process [159] is an expanded text of this chapter, with many detailed case studies. Therefore, for more details on troubleshooting the reader is referred to that book. 

To troubleshoot effectively, a technician needs to know whether a control valve fails open (FO) or fails closed (FC). When an automated valve is installed in a unit or process, the engineers take into account whether that valve should fail open or fail closed. Each valve operates differently for example, when a valve is designed to fail closed, a heavy spring causes the flow control element to move to the closed position. It takes instrument air to open the valve. A fail-closed valve would assume the following positions ... 

Control loop—a collection of instruments that work together to automatically control a process (such as pressure, temperature, level, flow, or analytical variables). A loop includes a primary element or sensor, a transmitter, a controller, a transducer, and a final control element. Information from control loops is invaluable in the troubleshooting process. 

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