Instrument downtime

Development of the method involved the installation of a system in an existing mass spectrometry laboratory and working with chemists for 3 months to determine specific needs and to develop a consistent, reliable procedure. The instrument was moved to an open-access laboratory and chemists were trained in its use. A key to making this approach a success is the fact that instrument downtime was kept to a minimum. Understandably, maintenance is done at off-peak times, and support mechanisms are put in place so problems are immediately addressed. Training and education was highlighted as a key factor for the successful implementation of this LC/MS system to optimize performance and to reduce the possibility of instrument contamination. 

Preventive maintenance helps the chromatographer to reduce instrument downtime, allowing for more efficiency and cost effectiveness in the HPLC laboratory. 

To limit instrument downtime, and if financially feasible, it is a good idea to have an extra ion source which can be exchanged after venting the instrument. This encourages more frequent source maintenance and provides more consistent analytical results. 

Instrument-based extraction techniques such as supercritical fluid extraction (SEE) and pressurized liquid extraction (PEE) offer advantages because of their potential for automation, more selective isolation of residues through tuning of parameters, and on-line clean-up of samples. Their applications have been slowed by the limited number of commercially available instruments, additional extraction costs, and instrumental downtime. Although several applications have been developed using SEE and PEE, these techniques are not widely used in routine laboratories. 

Because changes in pressure can be the result of an incorrect column, mobile phase, and/or flow rate, the first things to check are column specification, mobile phase composition, and flow rate. These are easy to check and might help to avoid costly instrument downtime. In the event that the pressure change is not the result of an error in column, mobile phase, or flow rate, the next course of action will depend on the nature of the problem. 

Several all-in-one tablet testers are currently available that measure weight, thickness, diameter, and hardness of tablets. In addition these instruments provide digital storage and calculation of statistical parameters and allow for rapid feedback during the tableting process so that the tableting equipment can be adjusted accordingly with minimal downtime. ... 

Several important aspects relevant to the implementation of fast LC technologies in pharmaceutical laboratories should be mentioned. First, increases in speed should not compromise the quality of the analytical data or the robustness of the chromatography. All methods must be reproducible and validatable to meet the applicable GMP and GLP requirements. Instrumentation should be easily maintained and have minimal downtime. 

This instrument ran very reliably while sampling every 30 seconds for 4 years from installation until the process was discontinued, with the need for only one lamp replacement and one replacement of the CPU cooling fan. Keeping the downtime to a minimum was essential, as this was a safety analysis if the analyzer was down, the process did not run. 

Unlit recently, these measurements could be taken only when the drill bit and string were removed from the borehole. However, in the mid-1980s, a new dimension was added, namely, measmement while drilling (MWD) instruments. These devices are mounted above the drill bit and around the drill string to provide a continuing source of data on downhole characteristics. This advancement reduces the drilling downtime previously required when measurements were taken. 

Although many pressure relief devices are called SRVs, not every SRV has the same characteristics or operational precision. Only the choice of the correct pressure safety device for the right application will assure the safety of the system and allow the user to maximize process output and minimize downtime for maintenance purposes. Making the correct choice also means avoiding interference between the process instrumentation set points in the control loop and the pressure relief device limits selected. These SRV operational limits can vary greatly even when all are complying with the codes. 

Most analysts will be required to troubleshoot the chromatography system at some stage. Although chromatographic instruments are considerably more rugged now than they once were, components still have limited lifetimes and need to be replaced. As operator error can be the cause of a problem, it is important to understand the operation of the system in order to minimize downtime. The best approach to troubleshooting, however, is preventive maintenance the most important points to remember are filter, degas, and flush.71... 

The data reduction hardware is based on a Hewlett-Packard 9825A desk top computer. It is supported by one megabyte of flexible disk storage, a printer/plotter and the necessary interface equipment for on-line LSC data collection. Reliability was a prime factor when the hardware was chosen. The LSC(s) and data system run virtually unattended, 24 hours a day, 365 days a year. Samples are typically counted for two minutes each plus one minute for the external standard. Therefore, data from the four counters are received by the HP9825A at an average interval of 45 seconds. With such a demand on the system, computers require good service support, more so than other instruments. Since installation in May, 1977, there have been less than two work days of cumulative downtime. 

It is also vital that any other components such as gaskets, O-ring seals, instruments, and other parts are checked for compatibility with the products to avoid failure in service and possible product contamination or equipment downtime for repairs to be made. 

The reduction of downtime of the instrument (i.e., operations of pump components, injectors, and detectors) can be controlled to some degree if sample solutions are filtered and/or centrifuged the use of a 0.2- or 0.45-pm-pore-size filter is generally recommend for removal of particulates [15]. Filtration as a preventive maintenance tool for FfPLC analyses is well-documented in the ht-erature [16-18]. 

Sample preparation is an important and necessary step in the overall analytical process, because most analytical instruments cannot accept the sample matrix directly. If these materials were to be injected, then the consequences may include a rapid deterioration in the separation performance of the chromatographic column, clogged frits or lines that result in an increased system back pressure, and detector fouling that may reduce system performance and result in downtime for cleaning the ionization source. 

Analyzers have the advantage of directly measuring the product quality, but also have the drawbacks of high maintenance and slow dynamic response. They have a greater downtime than other instruments, and may be particularly troublesome when the stream ana-... 

As described abeady in Chap. 6, instrument air and compressed air for operating purposes are normally supplied by the ah compressor in the air separation unit A receiver in the instrument air system ensures a continuous supply during malfunctions for a period of 30 minutes. A diesel-powered auxiliary compressor is usually installed to start up the plant and ensure compressed air supply during downtimes. 

When failure confirmation is not done, there are times when multiple instruments are replaced during system restoration. When the exact cause of a failure is not identified, multiple "failures" are reported when the maintenance technician replaces several items in an effort to find out which one has actually failed. During a period of unexpected downtime, the emphasis is clearly on system restoration and often time is not allocated for failure identification. This is understandable given many restore situations where there may be a harsh environment, little time and lack of test equipment. The result of recording multiple failures when only one exists is a failure rate that is too high. 

Incomplete instrumentation can severely hamper quick and accurate troubleshooting in fact, it can turn troubleshooting from a logical step-by-step process into a guessing game. Without good instrumentation it can be days, weeks, or even months before a problem is located and solved. When an extrusion problem results in off-quality product or downtime, it is very important to find the cause of the problem quickly because such problems can be very costly. In some instances, a downtime of just one day is more expensive than an entire new extruder In most cases, trying to save money on instrumentation is penny-wise and pound-foolish. 

Most newer plants and facilities contain control rooms, electric motor control centers, instrument control rooms, and computer centers. These are usually maintained under a slight positive pressure with makeup air being introduced from the outside. In many instances it is possible for this air to be contaminated with atmospheric pollutants such as sulfur oxides, hydrogen chloride, chlorides, hydrogen sulfide, dust, and others. These gases and dust can cause serious damage to sensitive circuitry found in computers, microprocessors, microswitches, and other delicate electronic equipment. If corrosive gases are removed from these makeup streams, costly maintenance and downtime will be prevented. 

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