Maintenance requirement

Deflagration and detonation flame arresters should be inspected annually until operating experience indicates otherwise. Also, the need for frequent inspection and maintenance may affect the selection of one type of flame arrester over another type for a specific application. For example, a hydraulic (liquid seal) flame arrester may be more suitable than a dry, fixed-element, flame arrester if the latter requires frequent inspecdon and maintenance because of persistent plugging problems. 

See Chapter 7 for a more detailed discussion of diis subject. 

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Cyclones can be used under conditions of high particle loading. They are cheap, simple devices with low maintenance requirements. Problems occur when separating materials that have a tendency to stick to the cyclone walls. 

The identification of pollution prevention options has become a maintenance requirement. In addition to these requirements, the National Institute of Occupational Safety and Health (NIOSH) performed its first investigation of indoor air quahty. The U.S. Department of Energy (DOE) has also begun to research air quahty. 

Economy of time and resources dictate using the smallest sized faciHty possible to assure that projected larger scale performance is within tolerable levels of risk and uncertainty. Minimum sizes of such laboratory and pilot units often are set by operabiHty factors not directly involving internal reactor features. These include feed and product transfer line diameters, inventory control in feed and product separation systems, and preheat and temperature maintenance requirements. Most of these extraneous factors favor large units. Large industrial plants can be operated with high service factors for years, whereas it is not unusual for pilot units to operate at sustained conditions for only days or even hours. 

Water Quality Maintenance. In addition to controlling algae and microorganisms such as bacteria, proper swimming pool maintenance requires control of free and combined available chlorine, pH, alkalinity, hardness, and saturation index. Ranges for various swimming pool parameters (Table 2) are recommended by The National Spa and Pool Institute (14). 

In the 1990s, the use of batteries in electric vehicles and for load leveling is being revived partly for environmental reasons and partly because of scarce energy resources. Improvements in battery performance and life, fewer maintenance requirements, and automatic control systems are making these appHcations feasible. Research and development is ongoing all over the world to develop improved lead—acid batteries as weU as other systems to meet these needs. 

Designed for continuous operation with minimum maintenance requirements... 

High maintenance requirements—especially if operation is cyclic... 

Maintenance and Reliability Preventive maintenance requires that all engines be shut down at periodic intervals for inspection and repair. For properly maintained heavy-duty engines availability is over 97 percent, with maintenance costs of 2.50 to 5 per horse-power-year and lubricating-oil consumption of 1 to 2 gal/hp-year. While this represents a high degree of reliability, outages of heavy-duty engines are more frequent than those of electric motors or steam turbines. 

Ceramic candles, which are thimble-shaped, porous, acid-resistant ceramic tubes. Although efficiencies exceeding 98% have been reported, the candles have high maintenance requirements because they are very fragile. 

The successful implementation of total productive maintenance requires ... 

Engineering factors include (a) contaminant characteristics such as physical and chemical properties - concentration, particulate shape, size distribution, chemical reactivity, corrosivity, abrasiveness, and toxicity (b) gas stream characteristics such as volume flow rate, dust loading, temperature, pressure, humidity, composition, viscosity, density, reactivity, combustibility, corrosivity, and toxicity and (c) design and performance characteristics of the control system such as pressure drop, reliability, dependability, compliance with utility and maintenance requirements, and temperature limitations, as well as size, weight, and fractional efficiency curves for particulates and mass transfer or contaminant destruction capability for gases or vapors. 

No moving parts, therefore, few maintenance requirements and low operating costs ... 

The slow rotation of the drum and reciprocation of the agitator reduce maintenance requirements to a minimum but the following should be inspected periodically. The strip liner of the trunnion bearing at the valve end will normally wear at the lower half. However, in situations when the slurry has a high specific gravity, the drum has a tendency to become buoyant causing wear to the upper half. 

Reliability of the corrective measure based on operating and maintenance requirements and... 

The maintenance requirements on these machines is labor intensive and mirrors those of its horizontal counterpart. 

Operating problems. High-temperature operations create high maintenance requirements and can reduce equipment reliability. 

Smokeless operation can generally be achieved, with essentially no noise or luminosity problems, provided that the design gas rate to the flare is not exceeded. However, since the flame is near ground level, dispersion of stack releases is poor and this may result in severe air pollution or hazard if the combustion products are toxic or in the event of flame-out. Capital and operating cost and maintenance requirements are high. 

Little or no maintenance requirements Small space requirements Available m many construction materials No power requirements other than pumping Mixing achieved m short conduit lengths Minimal chance of material hangup or plugging Short residence times NaiTow residence time distribution Enhanced heat transfer Cost effective... 

With alarm management, the high pressure trip would alarm, but the other associated alarms would be suppressed, since they are the expected result of the high pressure trip. On the other hand, a low flow condition from a different cause would be alarmed. Plants with managed alarms are inherently safer than those without since it is easy to silence and overlook a critical alarm in the midst of an alarm shower. However, the benefits should be balanced with the increased complexity and maintenance requirements. 

The advantages of thermal incineration are that it is simple in concept, has a wide application, and results in almost complete destruction of pollutants with no liquid or solid residue. Thermal incineration provides an opportunity for heat recovery and has low maintenance requirements and low capital cost. Thermal incineration units for small or moderate exhaust streams are generally compact and light. Such units can be installed on a roof when the plant area is limited. = The main disadvantage is the auxiliary fuel cost, which is partly offset with an efficient heat-recovery system. The formation of nitric oxides during the combustion processes must be reduced by control of excess air temperature, fuel supply, and combustion air distribution at the burner inlet, The formation of thermal NO increases dramatically above 980 Table 13.10)... 

Defined maintenance requirements specifying maintenance tasks and their frequency... 

Define maintenance requirements covering what is to be maintained, by whom, and to what depth. 

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