Abstract:
Apparatus (11, 11a, 11b, 11c) for heating substances (16, 16a, 16b, 16c) with microwave energy has a microwave containment housing (12, 12a) formed at least in part of thick microwave absorbent dielectric material (39, 39a, 39b) such as concrete or ceramic tile among other examples. Such materials are usually obtainable locally thereby avoiding the high costs of prefabricating all metal chamber components at a distant factory and shipping the bulky structure to the installation site. Unproductive absorption of microwave in the dielectric material is minimized, when necessary, by conductive elements (29, 29b, 42a, 42b, 64a, 64b, 67a, 67b) which reflect microwave energy. In the preferred form, such elements include a high strength metal conveyor (21, 21a, 21b, 21c, 21d, 29e, 21f) and means (68, 68a, 72, 73, 74) are provided, when necessary, to counteract underheating which may sometimes occur where substances contact a metal surface in a microwave field. The dielectric housing construction enables structural simplifications in conveyor entrance and exit tunnels (17, 18) and in access doors (53). The construction may include a series of separately energized, electrically isolated heating modules (13c, 13d, 13e, 13f) along the conveyor to increase processing capacity and to enable differing power levels at successive heating stages.
Abstract:
Asphaltic concrete constituents (13) or the like deposited in a windrow (14a) along a surface (12) to be paved are molded into a preliminary narrow layer (14b) of greater height than the final layer (14d) of pavement to be formed on the surface and are then heated by directing microwave energy into the preliminary layer. The heated preliminary layer is then spread out to form the final thinner layer of paving material for smoothing and compaction. Molding means (37) for the preliminary layer and microwave heating means (38) may be carried on a vehicle (16) which travels along the windrow. The vehicle may also carry mixing, spreading and compaction means (39, 92, 89) or some or all of these elements may be on a separate paver vehicle. The method and apparatus reduces an unproductive dissipation of energy, which can occur if microwave heating is performed with the paving materials spread out in the relatively thin final layer, by avoiding unnecessarily deep penetration of the microwave energy into the underlying surface that is to be paved. Auxiliary heating means (79), preferably using thermal energy recovered from the exhaust of engines (28) which drive the electrical generators (29) that energize the microwave sources (52), may be used to preheat portions of the surface adjoining the portion overlain by the preliminary layer.
Abstract:
Generating stations which each have a rotary voltage step-up mechanism integrated with an inertial energy storage device are connected in series through a transmission line to produce high-voltage utility electrical power from distributed primary energy sources, such as arrays of solar energy panels, wind-driven generators or the like, which may be intermittent. Each station in the series may include an elevated generator supported on insulative structure and operating at the high-voltage level of the transmission line to add an increment of voltage and power to the line. The generator is driven through an insulative drive shaft by a motor operated from the nearby primary energy sources. Each station further includes a massive flywheel secured to the drive shaft assembly that links the generator and motor in order to store locally developed energy during periods of excess supply whereby energy may be continued to be delivered to the transmission line during periods of diminished supply or to meet demand peaks.
Abstract:
Fragmented old asphaltic concrete or the like is recycled into new hot-mix by temporarily separating larger pieces from the smaller fragments, generating heat internally within the large pieces with penetrating microwave energy, separately heating the smaller fragments by exposure to hot gas, and then recombining and remixing the separately heated components. The old concrete can be heated very rapidly, highly uniformly and economically while avoiding asphalt degradation and pollution problems that can be caused by exposure to extreme high temperature and while avoiding the relatively high costs of heating the entire volume with microwave energy. Sorting, heating and mixing apparatus (11, 11a) embodying the invention may be made transportable to a site at or near a repaving operation or may be travelable along a roadbed to pick up old concrete and deposit new hot-mix or may be integrated into a fixed hot-mix plant (73, 73a, 73b) to enable, among other modes of operation, production of hot-mix wholly from old reclaimed concrete or production of hot-mix from both old and new materials in any desired proportions.
Abstract:
Asphalt roads or the like are repaved by heating and decomposing existing pavement with microwave energy and then remixing and recompacting the constituents of the pavement, the operations being performed at the original location of the old pavement and in some cases without removing the pavement constituents from the roadbed itself. A microwave energy applicator may be traveled along the pavement in front of remixing, grading and compacting equipment or some or all of the equipment may be integrated into a self-propelled vehicle. The vehicle may carry a microwave applicator followed by remixing means such as rotary tillers or the like and grading and compaction devices, and may travel continuously down a road which is reconditioned as the vehicle progresses. Motor generator sets on the vehicle power the microwave sources and the hot exhaust from the motors may be directed to the pavement to supplement the microwave heating and to maintain high temperatures during the additional operations. Apparatus is provided for efficiently coupling microwave energy into underlying pavement and for inhibiting the escape of microwave energy from the heating region, the apparatus being useful for heat treating concrete or the like as well as asphaltic pavement.
Abstract:
Portland cement concrete at a roadbed, bridge deck or the like is quickly and deeply heated and dried by directing microwave energy into the concrete and by applying hot gas to the surface. A layer of thermoplastic sealant is applied to the hot concrete followed by an overlayer of asphaltic concrete having a higher softening temperature than the sealant layer. Compaction then produces a composite pavement which is sealed against water intrusion and which can be quickly, easily and economically resealed and resurfaced at a later time using little or no additional paving materials. Resealing and resurfacing is accomplished by deeply reheating all three layers by microwave irradiation followed by recompaction. If cracking and deterioration are severe, the asphaltic concrete layer may be remixed and rescreeding between the reheating and recompaction steps. Both the initial production of the composite pavement and the restoration processes can be accomplished on a continuous process basis while traveling along the roadbed, bridge deck or the like.
Abstract:
Problems associated with moving fuel from remote sources to large centralized power generation plants are avoided with an economical system for collecting power from small stations located near the scattered, remote fuel sites. To avoid a need for many massive, costly transformers, a plurality of relatively low voltage generating stations are connected in series to cumulatively produce the high voltage needed for long-distance transmission line delivery. Power-generating devices of the successive stations are supported on insulative structures of progressively greater height and are driven or supplied with fuel through insulative means. The generating devices may take various forms including, for example, AC or DC generators driven through insulative drive shafts or fuel cells or magnetohydrodynamic devices supplied with fuel through insulative pipes and the system is adaptable to large-scale power production from scattered energy sources such as oil or natural gas wells, oil shale mines, geothermal steam wells, coal mines, solar energy sources or hydro-electric installations, for example. The stations may be adjacent, widely separated or vertically spaced apart within a single structure depending on the nature of the fuel source. Power may be converted to smaller voltages at the distribution region by coupling a plurality of electrical motors in series, each being supported on insulative structure, and each driving a generator through an insulative shaft.
Abstract:
A microwave energy reflecting zone (12, 12a, 12b) is provided below the surface of a pavement (11, 11', 11a, 11b) at a depth that is less than the maximum depth that such energy can penetrate into paving materials. The reflective zone, which is formed of electrically conductive material (16, 16a to 16h), results in energy and cost savings in subsequent paving or pavement repair operations that involve microwave heating of thermoplastic pavement and in which it is not necessary to heat down to the full depth to which such energy can penetrate paving materials. The heating is concentrated or localized within a predetermined upper portion of the pavement. The energy concentrating pavement may, for example, be more economically resurfaced when that becomes necessary by microwave heating followed by remixing and recompaction of the heated upper portion of the pavement material. The microwave reflective zone may be arranged to transmit a limited portion of downwardly propagating microwave energy to assure good bonding of the heated overlayer to the underlayer of paving material. Different microwave heating patterns, ranging from a highly uniform heating to heating which increases with depth, may be arranged for by locating the reflective zone at different depths.
Abstract:
Pavement (12) is rapidly heated in depth by irradiation with microwave energy accompanied by supplemental surface heating which counteracts an inverted temperature gradient otherwise produced by microwave heating. Energy efficiency is increased by performing the surface heating with thermal energy derived from the exhaust gases of a motor (19) which drives a generator (18) to energize the microwave source (68). An energy applicator (36) simultaneously applies both the microwave energy and hot gas to a selected area of pavement while blocking release of microwave energy in upward and outward directions and is preferably attached to a mobile support (37) through support and positioning linkage (38) which enables shifting of the applicator between localized areas of pavement to be heated. A variety of paving operations and pavement repair operations are facilitated by enabling an efficient deep rapid heating of deteriorated pavement or surfaces to be paved or repaved or to which an additional layer of pavement is to be applied.
Abstract:
Steam resources, which may in some cases be of forms heretofore considered unusable because of low energy content or corrosive contamination, are used for electrical power and water treatment operations in installations where these formerly separate activities may be combined, with the waste products of one being a valuable input to the other. In one embodiment, discharge heat from a steam driven generating station and contaminated sewage water, each of which formerly presented costly or environmentally hazardous disposal problems, are combined to produce sterilized water reusable for crop irrigation. In another embodiment, fresh water enroute to a municipal utility system is used to condense discharge steam from generating station turbines for return to the boilers while sterilizing the water to reduce or eliminate cholorination requirements. Still another embodiment enables use of turbine driven generators to produce electrical power from corrosive geothermal steam sources without exposure of the turbines to such steam and sewage water may be sterilized as a by-product of the system. Means are also disclosed for the large scale pumping of water utilizing such steam energy.