HUBER, Ilona, Katalin (Feketefej utca 19, Budapest, H-1029, HU)
1. Surface blow-off apparatus for removing snow from surfaces comprising a distribution duct having outlet orifices, the distribution duct being connected to a compressed air source,
characterised by that
the outlet orifices are implemented as nozzles (2, 3, 4) arranged in a network dividing the surface (1 ) to be protected into surface units.
2. The apparatus according to Claim 1 ,
characterised by that
the jet direction of the nozzles (2, 3, 4), the horizontal and vertical angular range of the nozzle jets, and the volume flow rate of the nozzles are adjustable.
3. The apparatus according to Claim 1 or 2,
characterised by that
it comprises nozzles (2, 3, 4) having dynamically variable jet shape.
4. The apparatus according to any one of the preceding Claims,
characterised by that
the distribution duct (7) is arranged under the surface (1 ).
5. The apparatus according to any one of the preceding Claims,
characterised by that
it comprises automatic control means (12) adapted for processing the signals of one or more status sensors (1 1 ).
6. The apparatus according to any one of the preceding Claims,
characterised by that
it comprises air heater means adapted for heating the air to be blown out by the nozzles.
The invention relates to a surface blow-off apparatus for protecting exposed surfaces from the accumulation of snow and from icing
According to known solutions, snow-covered surfaces may be cleaned of snow utilising snow shovels or snowplows (by pushing a passive implement on the surface), applying a snowthrower or snowblower (a passive implement combined with a rotating screw or auger and optionally a fan for blowing away snow). Snow removal utilising such implements is labour-intensive, has high energy costs, and may only be performed on flat surfaces.
Because of its significant weight load, snow accumulated on roofs of buildings should also be removed. Solutions for removing snow from roofs applying air blowing are disclosed in the documents DE 10 2006 022 980 A1 and JP 3,212,576 A. The document KR 100,825,079 B1 discloses an air curtain-like device for protecting non- load bearing roof surfaces of plastic greenhouses from the accumulation of snow by deflecting show flakes blowing air over the roof of the greenhouse.
The common characteristics of these known solutions are that they have restrictions on their application location, and they can be applied for removing snow and ice slabs formed from snow only after snowfalls with partial success that depends on the compaction degree of the snow layer.
Solutions including means for heating the surface to be protected from snow or ice are also known. These solutions typically apply electric heating wires laid down in the material of the pavement of the protected surface. Due to the high thermal inertia of the pavement the reaction time of such solutions is long, which implies that for effective protection the surface to be protected has to be heated in advance involving high energy consumption and costs. Under extreme conditions it may happen that the heating power of the device is not sufficient for melting the snow and/or ice present on the surface.
Mention should also be made of materials spread on surfaces to be treated for de- icing or anti-icing purposes. To a smaller or greater extent the application of such materials always causes environmental and/or material damage. The objective of the present invention is therefore to provide a solution that is capable of protecting exposed surfaces from the accumulation of snow or ice regardless of the specific properties of the location, and that may be operated in an energy-saving, economical and environmentally friendly manner. A further objective is that the apparatus should be capable of being adapted to the highly different characteristics of the different types of winter precipitation.
The solution applied by the present invention is based on the recognition that the easiest way to remove snow is to move it while it is still in the air. If snow is prevented from falling on the surface to be protected by blowing compressed air from nozzles arranged in the surface, or freshly fallen snow is blown off the surface in a similar manner, the formation of a snow layer, and therefore the compaction of snow by treading it down, and consequently ice formation and the accidents associated therewith may be prevented.
The objectives of the invention are fulfilled by the apparatus defined in the characterising part of Claim 1 . Advantageous implementation details of the invention are described in the dependent claims.
The invention is explained in detail below referring to the accompanying drawing, where
Fig. 1 shows the schematic top plan view of a surface blow-off apparatus installed over a surface area.
Nozzles 2, 3, 4 are disposed in the surface 1 that may be for instance a park or garden roadway lined with grass 16 and vegetation 17, and is preferably paved, having a solid tread surface. The nozzles 2, 3, 4 are generally arranged lowered in the surface 1 , while in case of stepped surfaces they may be disposed in a freestanding manner between adjoining steps.
A multifunction supply network forms an integral part of the apparatus according to the invention. The supply network consists of a compressor 9 adapted to provide air supply to the nozzles 2, 3, 4, a supply duct 10 supplying compressed air to the distribution elements, distribution ducts 7, and computerised sensor and control elements such as status sensors 1 and control means 12 arranged in a computer U2011/000124
network. Together with other primary system parameters, the dimensions and the duct layout of the supply system are determined in the design and dimension phases. Therefore, the apparatus according to the invention may become a snow removal and de-icing system perfectly adapted to the specific installation location in case it is designed and dimensioned taking into account the expectations of the customer as well as the characteristics of the location.
Being aware of design considerations and location characteristics, the exact locations from which snow should be removed and at which snow can be safely piled may be determined. In most cases there is plenty of room at the accumulation location 13 where snow may be blown by the apparatus. In case there should not be enough space for receiving blown off snow near the area to be kept clean, a number of alternative solutions may be applied. Such a solution may be the application of small- sized, visually appealing "snow traps" that either capture blown-off snow or even melt the snow, draining melt water, and also capture the air stream generated by the system. If necessitated by the lack of a suitable accumulation location, or if the amount of snow to be blown off would exceed a certain limit, high-efficiency snow traps applying snow haul conveyors may be installed. These simple and practical devices allow the easy and quick removal of snow from the area to be kept clean, depositing the snow at a suitable location.
The nozzles 2, 3, 4 may be produced in shapes and sizes that best suit the particular location where the apparatus is installed. Thereby the nozzles may have customised jet shapes, and a single nozzle socket may even include multiple nozzles with different characteristics. In the embodiment shown in the drawing the angular ranges of the nozzles 2, 3, 4, are, respectively, 180°, 90°, and 270°. Nozzles with other, arbitrary jet shape parameters may also be applied to match the shape of any given surface 1.
The operating characteristics and parameters of each system have to be established taking into account the local conditions (terrain features, the prevailing wind direction 14, nearby objects, roadways, etc.) before installing and commissioning a new system. The system thus obtained will be tailored to suit specific location conditions and the demands of the customer. Snow is removed from the surface 1 in a specific blow-off direction 15. A properly thought-out and carefully designed, logical snow removal plan, and an accordingly dimensioned automatised compressed air supply system may be devised for surfaces of any complexity and size. The apparatus according to the invention may therefore prevent the accumulation of snow on surfaces of any shape and size (be it ground or roof surfaces) independent of operator intervention, in an efficient and quick manner that provides fast and damage-free snow removal. It is thus not unimportant how the surface to be cleared from snow, ice, or sleet is treated; in other words, whether it undergoes any damaging effect. The apparatus according to the invention allows the damage-free removal of winter precipitation by blowing off snow from the surface to be kept clean and drying it without scratching and damaging the surface.
As it is well known from the literature of the field, winter precipitation may occur in highly different forms with very different characteristics depending on the conditions of precipitation formation, such as temperature.
Of all forms of winter precipitation freshly fallen snow has the lowest density, with the cohesion force (adhesion tendency) between particles being always the smallest. It is therefore worthwhile to promptly begin the snow removal procedure over the entire surface to be kept clean when the snow begins to fall, and to complete the procedure in the first phase of snowfall.
As long as the thickness of the freshly fallen snow is low, it only forms a loose, largely non-adhering, featherweight layer that may be removed completely from the entire treated surface utilising the programmed blow-off sequence method applied by the apparatus according to the invention. Thereby the inconveniences associated with the various forms of winter precipitation may be prevented before they could become a real problem.
If, however, an efficient and prompt intervention is not made during the first phase of snowfall, problems will gradually arise as time passes. As snow becomes thicker on the surface, it forms a continuous layer having increased density that is stickier and more slippery. The removal of such a layer is increasingly difficult.
The apparatus according to the invention implements an expediently automated surface blow-off system that prevents the accumulation of snow on surfaces to be treated in case of snowfall in an automated manner. The surface to be treated may for instance be the surface of pavements, roadways, roof structures, stairs, dangerous road sections with heavy traffic or other locations of increased importance, and may include areas that have been difficult to access utilising conventional means.
A specific feature of the inventive apparatus is that its operation is substantially synchronised with the duration of snowfall (or any other type of winter precipitation).
The apparatus easily blows off snow (all types of snow from powder to granular) from the surface to be kept clean, and may be applied for case of precipitation types of higher density (such as ice or glaze from hail or frozen or freezing rain).
The most dangerous precipitation type is freezing rain. To remove glaze from the protected surface, the apparatus blows heated dry air over the surface in a manner similar to snow removal.
An important advantage of the apparatus according to the invention is that it can be installed quickly, substantially without cutting or damaging the pavement of roads or sidewalks. Thereby the apparatus according to the invention may be applied on many surfaces where it is not allowed to completely cut open the pavement, or where such an undertaking would be overly costly or time-consuming.
A properly thought-out and carefully designed, logical snow removal plan, and an accordingly dimensioned automatised compressed air supply system may be devised for surfaces of any complexity and size. The apparatus according to the invention may therefore prevent the accumulation of snow on surfaces of any shape and size (be it ground or roof surfaces) independent of operator intervention, in an efficient and quick manner that provides fast and damage-free snow removal. It is thus not unimportant how the surface to be cleared from snow, ice, or sleet is treated; in other words, whether it undergoes any damaging effect. The apparatus according to the invention allows the damage-free removal of winter precipitation by blowing off snow from the surface to be kept clean and drying it without scratching and damaging the surface. The operating characteristics and parameters of each system have to be established taking into account the local conditions (terrain features, the prevailing wind direction, nearby objects, roadways, etc.) before installing and commissioning a new system. The system thus obtained will be tailored to suit specific location conditions and the demands of the customer.
The supply and nozzle networks consist of the following elements: a carefully dimensioned high-pressure compressed air pipe system, nozzles with specialised jet shape, pneumatic control elements, valves, and valve groups.
The efficient operation of the apparatus is based on the programmed logic of the nozzle network that provides among others the appropriate air distribution tracking the shape of the surface and the logical sequence of the blow-off intervention. Utilising such a programmed blow-off sequence the entire nozzle network may be kept under full temporal and spatial control, taking into account the data coming from the sensors. Thereby the efficiency of the apparatus according to the invention may be maximised for each individual surface to be protected.
In practice that means that the active operating time of the nozzles is limited to program-controlled time slots. The primary objective of limiting nozzle operating time is to keep air consumption at a minimum while fulfilling the original objectives of the invention. The intensity of snowfall usually permits that the nozzles are operated intermittently during the snowfall. Utilising sensor data (data coming from the temperature and wind direction sensors and the snowfall detector), the control system may automatically modify preprogrammed system parameters if necessary. Through sensor feedback the blow-off logic is capable of coordinated operation, adapting to changes in weather conditions.
In case of larger continuous surfaces a multiple-step approach is taken. Snow is blown off by the system in multiple stages, the sequence of the stages being controlled by the programmed control logic to optimise efficiency.
Nozzles located near the middle of larger surfaces always have to remove a smaller amount of snow than nozzles located closer to the edge of the surface in the blow-off direction. The apparatus according to the present invention addresses this problem by providing a combination of two solutions: by the application of nozzles with different blow-off volume flow and by utilising variable nozzle operating time limits. Nozzles installed towards the downstream edges (in the blow-off direction) of the surface to be protected have increasing air flow capacity to be able to safely blow off the snow blown outward by nozzles located nearer to the middle of the surface. Crucial parameters of the nozzles can be established in the design and dimensioning phase and thereby the nozzle network may be installed with the applied nozzles having the appropriate parameters.
Utilising the signals fed back from the status sensors 1 1 that provide information on the intensity of the snowfall and other environmental factors the programmed blow-off logic continuously controls and, if necessary, modifies the blow-off time slots assigned to individual nozzle groups by operating the built in valves 8.
The single objective of this control procedure is to provide the efficient operation of the apparatus according to the invention under changing environmental conditions for surfaces of any size and shape.
By programming the blow-off logic in an optimal manner the capacity of the available air source may be used optimally, which allows that all design conditions may be satisfied easily while the available resources and performance of the system may be utilised economically and cost effectively.
In addition to specifying the operating time slots for individual nozzles and nozzle groups of the nozzle network, nozzles and nozzle groups have also to be connected/differentiated spatially in the design phase. The nozzle network branches thus formed may then be freely operated in a simultaneous manner, fully conforming to the current operating time limits To provide optimal operating conditions for the compressor it is important to continuously operate all nozzles in a coordinated way as far as air consumption is concerned This is provided also by the preprogrammed control logic.
The pressure relations of the apparatus according to the invention may be established in possession of detailed data such as the location and shape of the surface to be protected, surface roughness values, weather parameters and intensity ratings, parameters of the nozzle network, combined air flow and operating pressure limits. These data provide enough information for selecting system components such as the compressor, tank, drying units and air treatment filter stages, and for the design and dimensioning of the supply network. Due to the significant range of available components, component selection may result in several alternative implementations of the inventive apparatus, with the most suitable solutions being those utilising VSD (variable speed drive) compressors. VSD compressors are capable of providing variable air flow in a wide range (between 20- 90% of the nominal air flow capacity), and thus are capable of responding to the continuously varying compressed air demand of the nozzle network according to orders received from the control logic. This allows further reduction of energy consumption that also has a beneficial effect on the service life and the operating parameters of the apparatus according to the invention.
In possession of meteorological data, the parameters of the surface to be treated, and the compressed air demand of an optimally configured and operated system the anticipated maximum air flow necessary for the efficient operation of the system under the most adverse weather conditions (high winds, prolonged snowfall, low temperatures) may be determined. VSD compressors represent a viable compromise as they provide energy efficient operation at the foreseen optimum air load, and can also fulfil the demands of occasionally occurring peak loads with optimal energy consumption.
The apparatus according to the invention may include visual indication of operation on the entire surface to be protected. This may be useful for pedestrians who otherwise might be surprised by the (completely harmless) blow-off impulses of the apparatus. The most suitable solution for visual indication of operation is the application of lights that give sufficient information even at night. For instance, a protected bipolar light emitting diode (LED) may be built in the surface of each nozzle, with the bi-colour LED indicating the active and inactive state of the nozzle by green and red lights. LEDs are controlled by the control unit of the apparatus, and thereby active impulses may be anticipated by blinking the LEDs for a few seconds before the onset of the impulse.
The smallest and possibly the most important constituent parts of the snow blow-off system of the apparatus according to the invention are the nozzles having special jet shapes. The role of the nozzles is crucial because in case the high-speed air that leaves the system is not properly focused or does not have the special flow characteristics that improve jet shape, the system will not function properly even with carefully thought out control logic and air supply and nozzle networks. 00124
The blow-off distance of nozzles may for instance be in the range of 180-330 cm. The effective blow-off distance of individual nozzles may vary depending on nozzle parameters, but it can be maintained that each nozzle may clean an area of 3-4 m 2 .
The apparatus also comprises a programmable microprocessor control unit, sensors, and a computer network for connecting the control unit and the sensors. These components provide coordinated operation, system supervision and self-diagnostics. Automation becomes fully fledged when the system is capable of controlling/detecting the correctness and availability of all the primary parameters necessary for its operation, and in case of a malfunction it is at least capable of generating error messages that can be evaluated later. It is thus also required to develop the central control system of the inventive apparatus consistently, such that it works coordinated with the self-diagnostics systems of for instance the compressors made by Atlas-Copco.
Since a very wide range of sensor types is available (temperature, humidity, surface moisture, wind direction and speed, optical contact (snowfall detector), pressure, flow velocity, etc.) those sensors and detectors that are most suitable for each specific installation location may be selected. The carefully designed and developed program of the snow removal logic sequence and the signals of the sensors applied for measuring and detecting the changes of environmental parameters together form an effective, automated snow removal and de-icing system that is able to react quickly to weather changes. The measurement data supplied by the sensors give information to the preprogrammed logic of the central control system, and thereby the apparatus according to the invention becomes a complete, automated system operating in a coordinated manner.
The apparatus according to the invention provides an ideal snow removal and de- icing solution that is capable of operating independent of the type, composition and amount of the snow, as well as of the temporal course of the snowfall, the changes of wind strength and direction, and temperature values. The snow removal procedure is based on a novel approach, provides increased efficiency with a convincingly short reaction time combined with significant performance, and is capable of continuous or occasional operation, as well as safe, non-stop availability ensuring quick intervention capability. The apparatus according to the invention does not need "rest time", 4
meaning that it performs its function without hesitation, with almost zero reaction time. Snow removal is performed without human presence or intervention in a preprogrammed manner, utilising the signals supplied by special sensors, quickly, quietly, and in optimal quality. The system is environmentally friendly, and has unmatched snow removal performance. The apparatus according to the invention may be operated cost-effectively, and its maintenance costs may be planned in advance. The inventive solution is more advantageous compared to currently applied solutions because, as opposed to the approach taken by existing solutions, emphasis is put on prevention and quick, coordinated intervention.
In winter, surfaces exposed to wet weather are prone to increased damage due to recurring cycles of thawing and refreezing. As sunshine eliminates ground frost, snow fallen on paved surfaces begins to melt, and meltwater soaks in the pavement. Water contained in the water-soaked pavements is frozen by the daily recurring heavy ground frosts that last during the night, which in the long run damages the material of the pavement. The damaging effect of repeated freeze-thaw cycles may become so intensive over the course of a few years that whole sections of the pavement have to be replaced, which has significant costs. In contrast to that, the surfaces treated by the apparatus according to the present invention are kept substantially dry at all times, because winter precipitation is blown off the surface while it is still in its solid form. Thereby the snow partially melting due to repeated daily thaw is not present on the surface to be treated when it undergoes melting.
Many widely applied pavement types have rough, ribbed, layered surfaces, or surfaces otherwise prone to damage, which pose difficulties to snow removal and de- icing utilising conventional means, often rendering conventional snow removal impossible. Contrary to that, the apparatus according to the present invention not only provides an effective and quick solution in these situations, but it may help protect these sensitive surface types.
The apparatus according to the invention is capable of minimising the detrimental effects of winter precipitation by decreasing the duration and costs, and thus increasing the efficiency, of snow removal operations. Meanwhile, the environmental load of the snow removal procedure remains below limits or may even be eliminated. Snow removal is carried out on multiple surfaces of different size quickly, in an economical manner, without human supervision or intervention. The apparatus provides non-stop operation, high structural and operational stability, exceptionally long service life, has low maintenance and operation costs, operates quietly in an environmentally friendly manner, fully taking into account the characteristics of the installation location.
List of reference numerals
6 air stream
7 distribution duct
10 supply duct
1 1 status sensor
12 control means
13 accumulation location
14 wind direction
15 blow-off direction
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