[en] The invention concerns a filter pack for air and/or liquid filtration with filter medium surfaces which are alternately folded between spacers, i.e. in the form of meanders, and form bags alternately open to the air inlet and outlet side. The spacers are of wave form and the edges of the spacer waves are running in parallel. It was the task to improve the filter pack so that high mechanical loads, higher operating reliabilities, lower reject rates, higher safety margins for disruption of operation and improved dedusting possibilities can be guaranteed. The solution is characterized by the design of the front of the spacers to be arranged in the closed bag which ensures protection against the filter medium surfaces. (orig./HP)

No abstract available

[en] A filter is moved from a store to an aerosol pipe by a lifting device and is clamped there. At the end of the operating period, the lifting device moves a new filter to a parking place. Control is from limit switches of the lifting, clamping and thrust devices and the position control of the store is by the limit switches. The filter changing device is enclosed in a gastight case, prevents blockage of a filter and makes it possible to set a certain operating period, to change the filter without interrupting the aerosol flow and to measure each filter in the sequence of operation outside the aerosol flow. (orig./HP)

[en] From the non contaminated area, the filter is enclosed in a leak tight bag which is affixed to the outside periphery of a supporting frame. The filter is placed in the bottom of the bag which is then welded in two places, a cut is then made between the two welds to achieve a sealed membrane separating the two halves of the vessel. An additional supporting frame is then placed on the frame. The new filter is secured in place and the sealed membrane is withdrawn from the contaminated part of the vessel

[en] Increasing requirements for exhaust-air filter systems used in nuclear facilities induced the Gesellschaft fuer Kernforschung to develop the ''Nuclear-Karlsruhe'' HEPA filter system. This novel development has profited by experience gained in previous incidents as well as by maitenance and decontamination work performed with different HEPA filter systems. The proved ''Nuclear-Karlsruhe'' system takes equally into account the demands for optimum safety, maximum efficiency and economy, and is distinguished by the following features: (1) The air current is defected by 180⁰ in the casing. Deflection causes quite a number of improvements, results in substantial reduction of space requirements, and avoids the dispersion of pollutants to the clean-air side. Besides, the HEPA filter is protected from damage by condensed particles or foreign materials entrained; (2) The ''Nuclear-Karlsruhe'' system allows gas-tight filter replacement. Special replacement collars have been provided at the casing, which allow the tight fastening of replacement bags which are self-locking. (3) In-place testing in the operating condition can be carried out very conveniently because the air is deflected. Minimum leaks in the filter medium or in the filter gasket can be detected by the high-sensitivity visual oil-thread test, which makes leaks distinctly visible as oil mist threads through a transparent front window provided on the clean-air side. The test takes only some minutes and its sensitivity is hardly matched by any other technique. (4) The clamping mechanism is installed outside the casing, i.e. outside the polluted or aggressive media. The contact force is spring-loaded absolutely uniformly to the circular filter gasket. (5) For practical and econmic reasons the filter casings can be locked individually so as to be gas-tight. (6) The entire system is made of stainless or coated steel and metal parts which are corrosion and fire-resistant. (author)

[en] The total test load for the three stations is increasing. The number of filters tested for DOE contractors is increasing. The number of filters tested per year for non-DOE customers has dropped substantially since 1978. The NRC pronouncement of filter testing has had an adverse effect on both the number of filters tested and on the quality of filters received since 1978. The test loads at Oak Ridge and Hanford are decreasing. Conversely, the test load of Rocky Flats is increasing. Significant differences in inspection, repair, and acceptance policies exist between the three stations. Significant and undesirable differences in report format and content exist between the three stations. Test machine operating practices are probably consistent from station to station, but have varied in the past. Periodic round-robins are needed to maintain and verify consistency of testing. The continued operation of the test stations is essential to maintain minimum levels of HEPA filter quality for nuclear applications

[en] Circular cross-section HEPA (High Efficiency Particulate Air) filters have been developed to replace the conventional rectangular type used for many years in nuclear installations to remove radioactive particulates. Among the advantages are improved sealing, easier changeout, better retention of contaminants and fewer waste disposal problems. (author)

[en] As reported in previous Air Cleaning Conferences, hot fire gases can impair the integrity of HEPA filters, and smoke particulates can plug them. This pressurizes the room of fire origin and can lead to the spread of radioactive or other toxic contamination. The heat-damaging effect has been overcome using water sprays in the duct. Previous studies on smoke plugging have been inadequate, however, in determining realistic pyrolysis/combustion rates and in evaluating the effects of fuel arrangements, room geometry, and aging of smoke particulates. To overcome these deficiencies, Lawrence Livermore Laboratory has constructed a full-size fire-test compartment, equipped it with an exhaust-ventilation system, and provided it with a suitable instrumentation- and data-acquisition system. From a survey of ERDA-contractor facilities, a matrix of fuel loadings (kg/m² of combustibles) versus dirty-to-clean ratios (relative yield of particulates) has been prepared. From this, a selected series of fuel arrays is being used to determine the life of HEPA filters during test fires. The effects of high- versus low-exhaust takeoff points, as well as the use or nonuse of sprinklers, are also being investigated. The fire test facility is described, and the preliminary results obtained to date are reported

[en] This invention concerns improved appliances enabling granules to be compressed, evenly on the whole, in a hopper, filter or any other component to be filled with such granules. This criterion is particularly important in the case of air filters using granulated adsorbing coal for separating the radioactive substances in the air should an ccident occur in a nuclear power station

[en] An improved version of the HEPA filter has been developed and evaluated for conformity with MIL-51068. In this design, the filter paper (conforming to MIL-F-51079) is pleated to a depth of only 18 mm. Ribbons essentially the same material as the filter paper form inter-pleat spacers, providing a crest-to-crest spacing of 3 mm. The resultant filter has the same DOP penetration level as the standard MIL-F-51068 HEPA filter, but about half its pressure drop at the same airflow. Materials of construction, adhesives, gaskets and faceguards match MIL-f-51068. Both flat-panel and zig-zag configurations of the filter meet the rough handling test of MIL-F-51068. Preliminary indications are that both filters will meet the overpressure tests of MIL-F-51068D and the flammability requirements of UL 586; these tests are in progress. Filters can be supplied to interchange with existing HEPA filter sizes. The improved pressure drop characteristic of these filters can be used to provide longer intervals between filter changes, or equal life at greater capacity