Design safety filters

When we start designing EMI filters, we will find that safety issues, thermal issues, and even loop stability concerns are intricately linked to the central issue of EMI. In particular, we must look closely at the aspect of safety, because even though we can attempt to sell equipment that doesn t function satisfactorily, product safety is a legal requirement without which we just cannot sell. So particularly in an off-line application, where the voltages are high enough to cause injury, safety becomes a major concern, even if we are just designing its EMI filter. 

After leaving the hydrogenator, the solution must pass through a safety filter prior to entering the oxidizer. Failure to remove all of the hydrogenation catalyst could lead to catastrophic H2O2 disproportionation in the oxidizer. Fixed-bed reactor designs alleviate the need for independent catalyst removal steps. 

Issue a safety bulletin to all other facilities to inspect the threads on filter pots of similar design. 

Filters are used for clarification, removal of small molecules, exchange of buffers, and concentration of product, as well as sterilization and virus removal. A recent review of validation of filtration describes the critical validation issues [29], Filter compatibility is tested with process conditions to avoid nonspecific binding of product to the filter or addition of extractables to the process stream. Extractables are defined and limits established based on final product safety studies. Special considerations apply for sterilizing filters and those that are designed for virus removal. These filters are single use, however, which simplifies the validation effort. 

Figure 3 shows the exhaust air disposal system. Several safety features have been built into its design. To prevent contamination of the surrounding atmosphere, excess air from the primary chamber and the exhaust streams from the dilution system are filtered, then fed into a combustion chamber where they are burned. 

As a member of a design group working on the design of a recovery system for SO, you have been asked to estimate the area necessary for a rotary vacuum filter to handle a zinc sulfite filtration. You are also to determine the horsepower of the motor necessary for the vacuum pump. Do not include any safety factors in your results. 

In the United States, methods for several pesticides at occupational levels in air are given in the National Institute for Occupational Safety and Health (NIOSH) Manual of Analytical Methods (Eller, 1994). The NIOSH methods for organochlo-rines and organophosphates utilize small traps with a particle filter backed up by two Amberlite XAD-2 resin beds. They are designed to be used with personal sampling pumps operating at flow rates of 0.2 to 1 L/min for maximum sample volumes of 60 to 240 L. Detection limits are in the 5 ng/m to 600 ng/m range. 

Another safety feature is a system of high-efficiency filters through which all air leaving the building must pass. These filters are designed to trap microscopic particles of radioactive materials that might otherwise be vented to the atmosphere. Other specialized devices and systems have also been developed for dealing with other kinds of accidents in various parts of the power plant. 

Consider the internal and external environment, medium characteristics, compatibility of all the materials used in the process, and the conditions of operation when studying your choices for components. Then, put your goal through the filters that will separate fact from fiction. Those filters are consideration of the cost, safety, and performance of your designed system. 

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