Water seal, maintenance

Two types of batteries having immobilized electroltye systems are also made. Tliey are most common m consumer appHcations, but their use m mdustrial and SLI appheations is mcreasmg. Both types hav e low maintenance requhements and usually can be operated m any position. Tliey are sometimes called valv e regulated or recombmant batteries because they are equipped with a one-way pressure rehef v ent and nomially operate m a sealed condition with an oxygen recombhiation cycle to reduce water loss. 

Covers for the battery designs in Figures 1 and 2 are typically molded from materials identical to that of the respective case, and vent plugs are frequentiy made of molded polypropylene. Other combinations are possible, eg, containers molded of polyethylene or polypropylene may be mated with covers of high impact mbber for use in industrial batteries. After the cover is fitted over the terminal post, it is sealed onto the case. The cover is heat bonded to the case, if it is plastic it is sealed with an epoxy resin or other adhesive, if it is vulcanized mbber. Vent caps are usually inserted into the cover s acid fiU holes to faciHtate water addition and safety vent gasses, except for nonaccessible maintenance-free or recombinant batteries. In nonaccessible batteries, the vent is fabricated as part of the cover. 

An intensive radial load is created when operating near the shut-off head and the shaft deflects at about 60° from the cut-water. This concept is explained in Chapter 9 Shaft Deflection . The pump will be noisy, will vibrate and maintenance on seals, bearings and shaft sleeves is expected. 

When a boiler may not be shut down for maintenance of the level control chambers isolating valves can be fitted between the water-level control and the steam space. In this instance, the valves must be capable of being locked in the open position and the key retained by a responsible person. When these valves are closed during maintenance periods the boiler must be under manual attendance. Fitting of these valves should only be with the agreement of the insurance company responsible for the boiler. Drains from the water-level controls and level gauges should be collected at a manifold or sealed tundish before running to the blowdown vessel. 

Maintenance-free battery— A rechargeable - battery that does not require replenishing of water during its service life. Usually the term refers to maintenance-free -> lead-acid and sealed nickel-cadmium batteries, which, in contrary to the conventional ones, are designed to suppress water loss due to -> electrolysis (overcharging) and evaporation. 

The x-ray tube assembly is a simple and maintenance-free device. However, the overall efficiency of an x-ray tube is very low - approximately 1% or less. Most of the energy supplied to the tube is converted into heat, and therefore, the anode must be continuously cooled with chilled water to avoid target meltdown. The input power to the sealed x-ray tube ( 0.5 to 3 kW) is therefore, limited by the tube s ability to dissipate heat, but the resultant energy of the usable x-ray beam is much lower than 1% of the input power because only a small fraction of the generated photons exits through each window. Additional losses occur during the monochromatization and collimation of the beam (see section 2.3). 

After closure, almost all mine sites will require several years of care and maintenance. Periodic inspections should be conducted to verify that all seals are intact and functioning correctly, and to ensure that water discharges are within the limits specified by the permits. It may also be necessary to clean out water diversion and containment structures, and to support revegetation by regrading, reseeding, applying fertilizer, and irrigating. 

Equipment wash solvent and water, laboratory samples, surplus chemicals, product washes and purifications, seal flushes, scrubber blowdown, cooling water, steam jets and vacuum pumps, leaks, spills, spend or used solvents, housekeeping (pad washdown), waste oils and lubricants from maintenance, and others... 

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