Device and Method for Building a Silo

The invention generally relates to an alignment device for aligning arced silo panels to form a silo wall during construction of a silo. The invention may also relate to a lifting device for lifting silo panels during the construction of a silo, and an arced silo panel for the construction of a silo. The invention may further relate to a method for constructing a silo. A silo may be understood to encompass storage tanks, in particular large storage tanks.

Mass production of increasing amounts of goods of varied nature makes it necessary to build storage structures of a proportionally growing capacity for storing materials. Industries such as the petrochemical, biodiesel, oil and the dairy industry, as well as wastewater treatment plants, water purification plants and, in general, every industry requiring the storage of large quantities of fuel, liquids, grains and other products, need large size silos in order to achieve competitive prices in the purchase of raw materials as well as in large-scale production.

The construction of large size silos presents a number of technological challenges which are hard to address. A silo is generally constructed using a multiplicity of stacked cylindrical rings to achieve the desired height. The traditional construction system starts from the base of the silo. The walls are built up from below, using cylindrical rings, starting from the lowest ring welded to the base and ending with the construction of the roof and the subsequent attachment of all fittings (ladders, piping, telemetry and control systems, etc.). This approach to the construction of silos brings about difficulties with regards to, amongst others, required equipment, safety, alignment, and quality of welding.

Attempts have been made to overcome the problems associated with the traditional methods of silo construction. For example, to ensure that the equipment necessary to join the cylindrical rings is not required to be raised, the silo under construction may be raised so that a new cylindrical ring may be provided under the part of the silo which is already constructed. As such, the silo under construction is raised, rather than all the materials necessary to form a new cylindrical ring. In this manner, e.g. welding equipment and/or alignment equipment, as well as the parts forming the new cylindrical rings, may be kept on the ground, which improves safety and efficiency.

A known method of constructing silos is to provide a multiplicity of separate silo panels, which are joined to form a cylindrical ring. These separate silo panels are generally pre-bent and often comprise outwardly projecting flanges around the periphery of the silo panel. Such separate silo panels are shown in WO00/49249. Even in such systems, the alignment of the silo panels provides significant challenges.

It is therefore desirable to provide an alignment device for the construction of a silo that has benefits and/or overcomes one or more disadvantages of silo construction devices/methods of the prior art. Exemplary benefits may be achievement of improved efficiency, lowered safety-risks, lowered production costs, and/or higher quality of the silo construction.

In the below relative positions will be mentioned, such as upper and lower. In the below, those positions refer mostly to the respective positions in the under construction silo. It will clear however that those positions can be generalized. Upper and lower generally refers to a first and a second at a distance. The invention is not limited to the specific in use positions.

The present invention addresses these problems by providing an alignment device for aligning panels, in particular arced silo panels, to form a silo wall during construction of a silo. The alignment device may comprise a base frame supporting an outer side and an inner side. The base frame with inner and outer side may form a U-shape having a space for receiving an arced silo panel in between the outer and inner side. Such an arrangement allows engaging the arced silo from multiple sides. The open side of the U-shape allows connecting a new arced panel to an existing arced part, e.g. an arced silo panel that is already part of the silo under construction.

The alignment device may further comprise at least one clamping unit provided on the outer side of the base frame, the clamping unit being arranged to clamp two flanges of a lower arced silo panel and upper arced silo panel together. In other or additional embodiments, the clamping unit may be on the inner side, or on both inner and outer side, of the base frame for clamping flanges that are part of an inner periphery of a lower and upper arced silo panel.

The alignment device may further comprise at least one pressing unit, comprising an inner panel aligner provided on the innerside and an outer panel aligner provided on the outer side. The pressing unit may be arranged to engage the lower arced silo panel and the upper arced silo panel, wherein the pressing unit is arranged to provide opposing alignment forces on inner and an outer sides of lower and upper arced silo panels.

Preferably, the pressing unit and the clamping unit are arranged to align the lower arced silo panel and the upper arced silo panel radially and vertically. The pressing an clamping units can position and align a new arced panel with an existing arced part, e.g. an arced silo panel that is already part of the silo under construction. To manipulate the position of the new arced silo panel with respect to the existing part, the clamping and pressing unit engage the new arced silo panel and the existing silo part. For constructing a silo, a new arced silo panel is added to the already constructed part of the silo that comprises other arced silo panels. The new part is to be held in position and is to be aligned with an arced silo panel that is already part of the partially constructed silo. To that end the pressing and clamping units engage on inner and outer sides of the arced silo panels during construction for positioning and aligning.

Further, the alignment device may have a drive arranged to move along a existing part of the silo under construction, that existing part being a stationary part. This allows to move the alignment device in a circumferential direction along arced panels, along the wall region of the silo under construction. As a result, the silo under construction can remain stationary, while the alignment device travels around its periphery. This is highly advantageous as it mitigates the need for rotating the entire silo during construction. Driving the alignment device allows moving the alignment device to a position that allows aligning the new arced silo panel into position with reduced lever. The alignment device can be driven to positions that allow engaging closer to misaligned regions. The alignment device can also be driven, after positioning and aligning and preferably fixing a new arced panel to the silo under construction, to a further position where it can receive the next new arced silo panel and start with positioning and aligning that next arced silo panel.

To mount the pressing and clamping units in a suitable position for alignment of the arced silo panels, the base frame has an outer and an inner side. The pressing and clamping units can then engage on inner and outer side of the received arced silo panel. In addition, the use of such a U-shape ensures that forces exerted on either side of the arced silo panels are communicated, thus providing opposing alignment forces. In an embodiment, the base frame, the outer side, and the inner side, are formed from a single frame defining U-shape, the frame defining the outer and the inner side. This is advantageous since the forces that need to be transferred between the outer side and the inner side are large, requiring high structural loads to be transferred through the U-shape. Preferably, these loads are transferred with low deformation of the U-shape. In an another embodiment, the base frame, the outer side, and the inner side are separately joined components, which act together to form the U-shape.

The clamping unit can generally exert a force in a vertical direction, resulting in bringing the new arced silo panel in a desired vertical position with respect to the arced silo panel of the under-construction-silo. In embodiments, the clamping unit is arranged to clamp two flanges of two arced silo panels together. In particular, when a new arced silo panel is provided into the system, underneath an existing cylindrical ring, the new arced silo panel is aligned with the existing cylindrical ring by clamping the top flange of the new arced silo panel together with the bottom flange of the arced silo panel above, which forms a part of the existing cylindrical ring. In this manner, the height of the new arced silo panel, and thus its height alignment with respect to the existing cylindrical ring, is set.

In embodiments, the silo is built from prefabricated pieces, in particular arced silo panels. In embodiments the arced silo panels are formed and shaped at the work location. The invention will be described with reference to arced silo panels, the silo can be formed from other pieces. Preferably the arced silo panels have a horizontal flange when the arced silo panel is part of the silo. The flange preferably extends in the radially outward direction, along a periphery of the arced silo panel. A horizontal flange of an arced silo panel already part of the silo can be engaged by the clamping unit and allows positioning the alignment device with respect to the already-partially constructed silo. A new arced silo panel having a similar horizonal flange can be aligned with the horizontal flange of an arced silo panel already part of the silo. The flanges will abut, which also allows connecting the flanges. The clamping unit can clamp on the top side of one flange and on the bottom side of the other flange, clamping the flanges together, resulting in alignment in the vertical direction.

The pressing unit can generally exert force on the new arced silo panel in a radial direction. To that end, the pressing unit can have an inner and an outer panel aligner. The new arced silo panel can be engaged at multiple spots. The silo-under-construction can be engaged at multiple spots. The pressing unit can be controlled to bring the new arced silo panel aligned with the already existing silo part in the circumferential direction. The pressing unit can provide opposing radial forces against both the newly provided arced silo panel and the existing cylindrical ring. As a result, the inner surface of the new arced silo panel and the inner surface of the existing cylindrical ring align, to radially align the new arced silo panel with the existing structure. Simultaneously, the outwardly extending peripheral flange of the new arced silo panel is aligned with the flange of the existing cylindrical ring.

In a preferred embodiment, the clamping unit comprises two opposing clamping wheels. These wheels may be provided on two substantially parallel and substantially horizontal axes, said axes being vertically spaced from one another. The clamping wheels are preferably arranged to clamp two flanges of two arced silo panels together. The wheels are mounted on rotatable shafts that e.g. are connected to the frame via one or more bearings.

In embodiments the clamping unit comprises two opposing clamping wheels. The wheels can roll over the flange of the silo, in particular a flange of the silo panel. This allows the alignment device to move along the wall region of the silo under construction. As a result, the silo under construction can remain stationary, while the alignment device travels around its periphery. This is highly advantageous as it mitigates the need for rotating the entire silo during construction.

In a preferred embodiment, at least one of the clamping wheels is driven to move the alignment device along the silo wall. In an alternative or additional embodiment, an external drive system may be provided to move the alignment device along the stationary silo wall. In an embodiment, at least one of the horizontal axes of the clamping wheels is driven by a drive unit. In a preferred embodiment, the drive unit is an electromotor. Preferably, a single drive unit is arranged to drive multiple axes, by a drive chain, provided over two or more axes. That way, if one axis is driven, it will translate rotational force to a second axis.

In a preferred embodiment, the clamping wheels are made of a hard material, preferably a metal, more preferably of steel. Since the coefficient of friction between the material of the arced silo panels and such wheels is generally low, it is preferred to have more than one wheel being driven to prevent the wheels from spinning on the surface of the flange or on the surface of the arced silo panel. That way, more control is provided over the alignment device due to improved traction between the arced silo panels and the wheels.

In a preferred embodiment, the clamping unit is arranged to suspend the alignment device from a flange of an arced silo panel. In such an embodiment, the alignment device is suspended from the silo under construction. As a result, the alignment device can freely move around the periphery of the silo without the need of additional guiding material, such as tracks, cables, carts, or the like. In addition, the friction required to move the alignment device is reduced, so that a drive unit needs less power to move the alignment device along the silo wall. The clamping unit provides the necessary force to clamp the alignment device onto the flange and to suspend the alignment device from the flange.

When a new arced silo panel is provided into the system, it is attached to the arced silo panel which was previously joined to the silo under construction. This is done by joining straight opposing side sections of the peripheral flange using e.g., bolts. The connected side sections extend generally in a vertical direction. The new arced silo panel is also grabbed by the clamping unit at the top flange that will generally extend in the horizontal direction. The top flange of the new arced silo panel is then clamped together with the bottom flange of the existing cylindrical ring, above the new arced silo panel. The new arced silo panel and the alignment device are then suspended from the bottom flange of the existing cylindrical ring.

As the alignment device is driven along the periphery of the silo, the silo being stationary, the seam between the new arced silo panel and the existing cylindrical ring is welded, thereby joining the new arced silo panel to the existing structure. In other embodiment a temporary connection is provided first before a permanent connection such as welding. As a result of this procedure, the weld is only provided as the new arced silo panel is aligned with the existing structure.

In an embodiment, the alignment device further comprises one or more wheels provided on the base frame, the wheel being arranged to support the alignment device on the ground, and to move the alignment device along the periphery of a silo under construction. In an embodiment, the alignment device further comprises a rail wheel provided on the base frame, the rail wheel being arranged to support the alignment device on a track.

Alternatively, or in addition to at least partial suspension of the alignment device, a rail wheel may be provided on the base frame, such that the alignment device can be moved along a track provided on the floor of the silo to be constructed. In such an embodiment, a track is provided in the shape of the silo to be constructed, and the alignment device travels along the track to build up the silo structure. Such an arrangement may aid in stability of the system and may reduce load on the flanges of the arced silo panels.

In an embodiment, the inner panel aligner may comprise at least one inner pressing unit. The inner pressing unit may comprise at least one inner pressing wheel. The inner pressing wheel may be provided on a substantially vertical axis and preferably being arranged to engage with two arced silo panels and to provide an outwardly directed pressing force on the two arced silo panels.

In an embodiment, the outer panel aligner may comprise at least one outer pressing unit. The outer pressing unit may comprise at least one outer pressing wheel. The outer pressing wheel may be provided on a substantially vertical axis and preferably being arranged to engage with two arced silo panels and to provide an inwardly directed pressing force on the two arced silo panels.

The use of an inner and/or an outer pressing unit having at least one inner and outer pressing wheel, respectively, allows the alignment device to travel along the arced silo panels, while reducing friction. As a result, a high pressing force can be exerted, without a high friction while the alignment device travels along the silo wall. As such, the alignment device can be moved along the wall of the stationary silo under construction, while allowing for large alignment forces to be applied by the pressing unit.

In a preferred embodiment, the inner panel aligner comprises at least two inner pressing wheels provided on a substantially vertical axis. In an embodiment, the inner pressing wheels may be provided on separate substantially vertical axes. By providing at least two pressing wheels, the inner panel aligner can provide pressing forces on two arced silo panels without providing a force to the seam between the two arced silo panels. This is advantageous since the seam is preferably welded, the generated heat of which may lead to increased malleability.

In addition, the provision of two vertically spaced inner pressing wheels that are arranged to engage a lower and a upper arced silo panel respectively, allows for access to the seam between the new silo arced silo panel and the existing cylindrical ring. As a result, the welding may occur closer to the point where the arced silo panel is best aligned.

Similarly, in an embodiment, the outer panel aligner comprises at least two outer pressing wheels, which are arranged to provide a pressing force to two arced silo panels without engaging the flanges in the seam area of the two arced silo panels.

In an embodiment, the alignment device may further comprise a pre-alignment unit comprising a further clamping unit and/or a further pressing unit, said pre-alignment unit being arranged at a lateral distance such that the pre-alignment unit is arranged to engage with an arced silo panel to pre-align the arced silo panel. The pre-alignment unit is positioned upstream, so in the driving direction, from the main alignment units

The pre-alignment unit is preferably positioned at a lateral distance such that it is the first point of contact for a new arced silo panel. The pre-alignment unit can then bring the arced silo panel in a position such that it can be engaged by the rest of the alignment device. This allows the tolerances of the rest of the alignment unit to be lowered, since the pre-alignment unit can bring the new arced silo panel in such a position that it already closely conforms to its eventual position. The engagement points of the alignment device on a first side are provided by the pre-alignment unit, while the engagement points on a second side are defined by the last clamping unit and/or pressing unit of the alignment device. These engagement points define a distance therebetween. In a preferred embodiment, the pre-alignment unit is provided at a lateral distance such that the ultimate distance between the engagement points is more than the length of an arced silo panel, preferably of about the length of two arced silo panels. In an embodiment, the distance between the engagement points between about 1 and 8 meters, preferably between about 2 and 6 meters.

In an embodiment, the alignment device may further comprise a welding unit. The welding unit preferably comprises a welding torch mounted on the inner side of the base frame. In a preferred embodiment, the welding torch is mounted adjacent to the inner panel aligner. The welding torch is preferably arranged to provide an elongated weld along two arced silo panels as the alignment device travels along the arced silo panels.

In a preferred embodiment, a welding unit is integrated in the alignment device so that the aligned panels are automatically welded upon placement. As a result, the weld is integral with the alignment procedure and risks associated with manual welding are lowered.

In an embodiment, the alignment device further may comprise at least two laterally positioned clamping units, preferably at least four laterally positioned clamping units, more preferably six laterally positioned clamping units. By providing multiple laterally positioned clamping units, the new arced silo panels are better aligned and balanced in the alignment device. In addition, a multiplicity of clamping units can also divide a driving force better, preventing the wheels to slip on the flanges.

In embodiments, multiple clamping units, each with wheels are provided, each engaging on the flange of the silo. This allows welding at a position in between two clamping units. This makes sure that the flanges are correctly clamped and held in aligned positions during welding.

In an embodiment, the alignment device may comprise at least two laterally positioned pressing units, preferably comprising at least three laterally positioned pressing units, more preferably comprising at least four laterally positioned pressing units.

In an aspect of the invention, there is provided an arced silo panel for the construction of a silo. In an embodiment, the arced silo panel comprises an arced wall defining a section of a cylindrical shape to form a silo panel body being arced in a first angular direction, and substantially straight in a second direction defining a height, perpendicular to the first angular direction. As a result, a multiplicity of laterally positioned panel bodies defines a cylinder. Further, the arced panel body defines a convex outer surface.

In an embodiment, the arced silo panel may comprise a circumferential flange provided around the periphery of the arced panel body, said flange extending outwardly, in the direction of the convex outer surface. The flange may define arced top and bottom sections, and straight opposing side sections. The flange may be interrupted at the ends of the opposing side sections. This allows a wheel to pass over the arced top and bottom sections, between adjacent arced silo panels. Advantageously, such an arced silo panel allows the continuous movement of the alignment device having clamping units with wheels. That is, the clamping wheels can continuously move over the flanges of arced silo panels forming the silo, without being interrupted by a side flange. The opening provided in the opposing side sections by interrupting the flange thus allows for a continuous movement of the alignment device.

In an embodiment, the arced silo panel may comprise a lifting clamp extending outwardly from the outer surface. In a preferred embodiment, the lifting clamp is provided at a distance of about a quarter along the first angular direction of the arced silo panel, said lifting clamp comprising an engagement element to communicate with a lifting device. Preferably, the lifting clamp extends substantially parallel to the straight opposing side sections.

The provision of a lifting clamp allows a lifting device to engage with the silo panel to lift the silo once a cylindrical ring has been formed from the arced silo panels. By lifting the silo using such lifting devices, the silo is raised for the formation of a new cylindrical ring.

In an embodiment, the lifting clamp is provided centrally along the arced wall. In such an embodiment, the central lifting clamp is provided substantially in the middle of the first angular direction.

The use of a central lifting clamp a lifting device to raise the silo even if the subsequent panels are provided in a staggered manner with respect to the previous cylindrical ring. In particular, the use of a central lifting clamp ensures that the lifting device can either engage with the combination of two opposed side flanges of lateral panels, or engage with the central lifting clamp. Either way, a staggered pattern of silo panels can be used without the need to shift the lifting devices to lift the silo to the next level.

In an embodiment, the central lifting clamp extends upwards over between about 5% and 80% of the height, preferably to between about 5% and 60% of the height, more preferably to between about 5% and 50% of the height. A lower central lifting clamp ensures that the panel can be grasped with less height of the lifting device required. The same holds for a lifting clamp being provided on the silo panel.

In an aspect of the invention, there is provided a lifting device for lifting arced silo panels during the construction of a silo. The lifting apparatus may comprise a base, a vertical frame, connected to the base, and a lifting jack, arranged to travel along the vertical frame.

In an embodiment, the lifting jack may comprise an engagement unit, preferably a hook. Preferably, said engagement unit is moveable in a direction substantially perpendicular to the vertical frame, so that the engagement unit can move outwardly and inwardly to engage and disengage with an engagement element of the lifting clamp on an arced silo panel.

The use of such a lifting device ensures that the silo may be raised during construction without the need for a lifting device being the height of the silo. Rather, the lifting device can lift the silo so that a new cylindrical ring can be provided underneath. The silo can then be placed on the ground or on blocks by the lifting device. The lifting device will then engage with the engaging element of the silo panels of the newly formed cylindrical ring, and raise the silo to provide a space for new arced silo panels for the formation of a ring. The lifting device can then lift the silo again, to form a space sufficient for the formation of a subsequent cylindrical ring.

In a preferred embodiment, the engagement unit is a parallelogram hook.

In an embodiment, the lifting jack may be arranged to engage with the engagement element of the lifting clamp of the arced silo panel according to any of the embodiments discussed hereinbefore.