Patent Application
20240167239
U.S. Pat. No. 10,626,569 is hereby incorporated herein by reference in its entirety.
The present invention generally relates to fish passages for use with dams and hydropower, and more specifically to fish passages and scaled hydropower.
Hydropower or water power is power derived from the energy of falling or fast-running water, which may be harnessed for useful purposes. Since ancient times, hydropower from many kinds of watermills has been used as a renewable energy source for irrigation and the operation of various mechanical devices. In the late 19th century, hydropower became a source for generating electricity. Since the early 20th century, the term has been used almost exclusively in conjunction with the modern development of hydroelectric power. International institutions such as the World Bank view hydropower as a means for economic development without adding substantial amounts of carbon to the atmosphere, but dams can have significant negative environmental impacts. One of the most problematic environmental issues is blocked passage for migratory fish, particularly anadromous and catadromous species. Hydropower licensing agencies—such as the Federal Energy Regulatory Commission in the USA—routinely require as a condition of operation that safe, timely and effective fish passage equipment at any hydropower plant be provided for. The problem is that doing so in a manner that is acceptable to authorities and stakeholders is extremely expensive, especially at smaller hydropower facilities where it becomes a disproportionate part of project cost and as such can render such efforts financially unworkable. As such, a lower cost approach that is effective at passing fish safely is of the utmost importance to owners and developers of small hydropower installations.
The following presents a simplified summary of the innovation in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is intended to neither identify key or critical elements of the invention nor delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.
In one embodiment, an assembly includes a first vertical stack having a first module and a second module made of cast-in-place concrete with or without bar or fiber reinforcement, or precast concrete with or without bar or fiber reinforcement, or steel alloy, or aluminum alloy, or glass fiber reinforced plastic, or carbon reinforced plastic or a hybrid or combination of any two or more of these materials, and a first seal horizontally installed between the first module and the second module, and a second vertical stack having a third module and a fourth module made of cast-in-place concrete with or without bar or fiber reinforcement, or precast concrete with or without bar or fiber reinforcement, or steel alloy, or aluminum alloy, or glass fiber reinforced plastic, or carbon reinforced plastic or a hybrid or combination of any two or more of these materials, and a second seal horizontally installed between the third module and the fourth module. The assembly further includes a third seal vertically installed between the first module and the third module, the third seal configured to span across vertical joints between the first vertical stack and the second vertical stack. The horizontal seals and the vertical seals are configured to provide near water-tight connections between the horizontal joints and the vertical joints such that the assembly has a leakage rate of less than about 0.1 gallon per minute per linear foot of joint.
In one embodiment, an assembly includes a first plurality of modules assembled to form a first vertical stack and a second plurality of modules assembled to form a second vertical stack. Each of the first vertical stack and the second vertical stack includes at least one of: a first plurality of horizontal seals between the first plurality of modules, and a second plurality of horizontal seals between the second plurality of modules. The assembly further includes a plurality of vertical seals installed between the first plurality of modules and the second plurality of modules. The first plurality of horizontal seals, the second plurality of horizontal seals, and the plurality of vertical seals are configured such that the system has a leakage rate of less than about 0.1 gallon per minute per linear foot of joint.
In one embodiment, a system includes an assembly configured to secure to a foundation. The assembly includes: a first vertical stack having first module and second module, and first seal horizontally installed between the first module and the second module, and a second vertical stack having third module and fourth module, and second seal horizontally installed between the third module and the fourth module/The assembly further includes a third seal vertically installed between the first module and the third module, and between the second and fourth module, the third seal configured to span across vertical joints between the first module and the third module and to span across vertical joints between the second module and the fourth module, which includes the quad point. The first seal, the second seal, and the third seal are configured to provide low-leakage connections between and among the first module, the second module, the third module, the fourth module of the first vertical stack and the second vertical stack such that the system produces acceptable leakage levels.
In one embodiment, an assembly includes a first vertical stack having a first module, and a first seal horizontally installed between the first module and a foundation on which the assembly is disposed; a second vertical stack having a second module, and a second seal horizontally installed between the second module and the foundation. The assembly further includes a third seal vertically installed between the first module and the second module, the third seal configured to span across vertical joints between the first vertical stack and the second vertical stack. The horizontal seals and the vertical seal are configured to provide near water-tight connections between the vertical joints such that the assembly has a leakage rate of less than about 0.1 gallon per minute per linear foot of joint.
In one embodiment, an assembly includes a first vertical stack having a first module and a second module, and a first seal horizontally installed between the first module and the second module. The horizontal seal is configured to provide near water-tight connections between horizontal joints of the first and second module such that the assembly has a leakage rate of less than about 0.1 gallon per minute per linear foot of joint.
These and other features and advantages will be apparent from a reading of the following detailed description and a review of the associated drawings. It is to be understood that both the foregoing general description and the following detailed description are explanatory only and are not restrictive of aspects as claimed.
The invention will be more fully understood by reference to the detailed description, in conjunction with the following figures, wherein:
The subject innovation is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It may be evident, however, that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the present invention.
Generally, in various embodiments, the present invention provides a fish passage system that can be easily assembled onsite and installed in a waterway, so that fish (e.g., salmon, shad and river herring) can overcome dams, hydropower facilities, and other obstacles encountered during migration. The fish passage can be disassembled and transported to and from sites. The disclosed fish passage system can be configured as a volitional or non-volitional passage depending on what ancillary attraction flow systems are utilized. Volitional fish passages can be defined as those that rely upon motivation, performance, and behavior of the fish to enter and ascend over the barrier, as opposed to non-volitional ones that rely on mechanical or human assistance such as lifts, elevators, fish locks, and trap-and-transport systems.
Referring to
The conduit 102 can be configured as a series of interconnected pools 103. A series of baffles 106 can be disposed along the conduit 102 at regular intervals to separate the pools 103. Each baffle 106 can be adjustable in height and width to create a baffle throughway 107 between an end of the baffle 106 and an inside surface of the chute/conduit 102. In an embodiment, the baffles 106 can be attached and secured to walls of the chute/conduit 102 with textile gussets or other fasteners. The baffles 106 can be made of the same or similar textile materials as the conduit 102. The fish passage system 100 can be assembled on site from a prefabricated, standardized, and modular kit of parts. The kit of parts can be configured to accommodate various passage heights, e.g., from about 7 to about 50 feet.
In an embodiment, the modules 104 that support the chute/conduit 102, as well as system 100 generally, can be configured as structural steel frames with overall size and dimensions of a standard intermodal shipping container. For example, in an embodiment, each module 104 is 8′ wide, 9.5′ high and 20′ long and can be oriented with the long axis parallel to river flow. The modules 104 can be used as building blocks to assemble various structures, such as, the structural frames to support the conduit 102 and system 100. The modules 104 can be stacked on top of each other to a desired height and attached together, vertically and/or horizontally, with bolted structural connections or other fasteners. The modules 104 can also be used to build dam-module stacks, spillway-module stacks, and turbine-module stacks to assemble a modular hydropower installation. In an embodiment, each stack 105 of modules 104 is individually secured to a foundation on a streambed using a post-tension anchor, but each stack 105 is not secured or affixed to adjacent stacks 105. This independent stack configuration allows for easy modification, replacement, and maintenance of structures utilizing stacks 105. In an embodiment, a compressible gasket of neoprene or similar material can be used to seal all interface and contact points between modules 104, stacks 105, foundations and other interfaces or joints. The compressible gasket can be sized to be positioned between modules and interfaces on the downstream side of a particular structure.
In operation, initially modules 104 and stacks 105 of modules 104 can be arranged and secured at desired locations and heights to adjust the slope of the conduit 102 based on design specification requirements, topographical constraints, flow volume, flow rate, type of fish, etc. The conduit 102 can then be expanded and supported between the structural framework, and the baffles 106 can be installed and adjusted as desired along the length of the conduit 102 in each pool 103. Water entering the upstream end of the conduit 102 flows through the interconnected pools 103 via the baffle throughway 107 in each baffle 106. Fish entering the downstream end of the conduit 102 traverse the pools 103 and oncoming water in the opposite direction via the baffle throughway 107 in each baffle 106. Upon exiting the system 100, the fish are deposited upstream of the obstacle or barrier in the waterway.
Referring to
In one exemplary embodiment, the center column 201 is a 40 ft. tall, 12″ diameter steel pipe with ½″ wall thickness. It attaches to a concrete footing 205 roughly 11′×11′×4′ thick. A bolted connection is used so fasten the column 201 to the footing 205 so that the connection can be disassembled if necessary. The chute/conduit 102 can be 8′ wide and 5′ deep and capable of supporting water to a depth of 4.5′. The conduit 102 and baffles 106 can be supported and secured on the channel edge supports 301, which can be made of 8″ square steel tubing having about 0.375″ to 0.5″ wall thickness. The edge supports 301 are beams, i.e., loaded in flexure. The chute/conduit 102 is suspended from the center column 201 using suspension tethers/cables 202, which extend from the top of the center column 201 and attach to the channel edge support 301 and to horizontal strut beams 203. The suspension tethers 202 can be a ⅝″ diameter wire rope or solid rod. The horizontal strut beams 203 can be an 8″×8″ square structural steel tubing with ½″ wall thickness. The entire structure can be stabilized with ground anchors 204. Fish passage systems 100, 200 can be easily assembled, disassembled, and stored in a support module 104 during transport to other sites (see
In addition, many fishways include an auxiliary water pipe to provide attraction flows. The small footprint of the fish passage system 200 allows for an auxiliary pipe to be installed from the upstream end 302 of conduit 102 and extending down through the open center area of the spiral configuration. This water pipe can be made of flexible textile materials and can be detached along with the chute/conduit 102 and stowed for protection during high floods.
Referring to
The fish entrance 601 of the conduit 502 can be releasably attached to a module 104 that is secured to a riverbed via a concrete footing 605 and a post-tension anchor. The fish entrance 601 can be oriented to face upstream so that fish traveling downstream can easily enter the conduit 502 via the fish entrance 601. The conduit 502 can include access ports 602 along its length that can be opened to remove debris and sediment, and to allow trapped air to escape. The access ports 602 can be made of textile materials. The conduit 502 can also include stiffening rings 604 along its length to retain the shape of the conduit 502 to keep the fish entrance 601 open. The stiffening rings 604 can be secured to the riverbed with mooring lines 603 and ground anchors 204.
Certain species of fish, such as, Atlantic salmon smolts, American shad and blueback herring, swim near the surface. Therefore, the conduit 502 and fish entrance 601 can be positioned near the top of the module 104 to interact with migrating fish. Specifically, as shown in
Referring to
With an ability to monitor the environment within the conduit 502, the fish passage system 500 can be modified to improve fish survival rates and reduce costs. Sections of textile materials comprising the conduit 502 can be inexpensively replaced or easily modified. For example, if reduced water flow through the conduit 502 is found to be acceptable, smaller diameter sections can be used, or existing sections can be pleated to make them smaller. In an embodiment, sections of textile material forming the conduit 502 can be attached to each other with rigid couplings and external stiffening rings.
Generally, as discussed above, the modules 104 can be used as building blocks to assemble prefabricated, modular systems for dams and hydropower facilities. The modules 104 can be stacked on top of each other to a desired height and attached together, vertically and/or horizontally, with bolted structural connections or other fasteners. Modules 104 can be utilized to build dam-module stacks, spillway-module stacks, and turbine-module stacks to assemble a modular hydropower installation.
In an embodiment, each stack 105 of modules 104 can be configured to be structurally independent by ensuring that there are no structural connections between adjacent stacks 105. In other words, each stack 105 can be individually secured to a foundation on a streambed using at least one post-tension anchor, but each stack 105 is not secured or affixed to adjacent stacks 105. This independent stack configuration allows for easy modification, replacement, and maintenance of stacks 105 individually.
Referring to
In an embodiment, each stack 105 can include vertical seals 1401 that can be installed vertically on the downstream side between adjacent stacks 105 to prevent leakage and provide a water-tight connection. Similarly, horizontal seals 1501 (see
Referring to
As shown in
The foundation structure 1700 can further include a single or series of prefabricated, transverse reinforced concrete slabs 1703 that can be positioned on top of the concrete segments 1701. In an embodiment, the concrete slab 1703 can measure 1′×4′×8′. In various embodiments, multiple transverse concrete slabs 1703 can be stacked at different orientations to accommodate a desired design or specification. For example, two slabs 1703 can be stacked with each having, for instance, a 90 degree difference in orientation. In an embodiment, sockets can be precast into the concrete segments/planks 1701, and the slabs 1703 can include a sleeve and bolt that is used to connect and tension the planks 1701 and slabs 1703 together.
Prior to installing the foundation structure 1700, initial preparatory steps include removing loose, compressible and organic streambed materials to reach competent soil or bedrock, leveling the soil or bedrock, using chair jacks to level the base planks and then filling in with grout. Grout cures faster than concrete, has limited leaching compared to cast-in-place concrete, can cure in the wet, and has been approved by the Federal Energy Regulatory Commission to arrest seepage.
The foundation structure 1700 can also include a foundation base module 1704 that can be configured, in an embodiment, as a 8′ wide×20′ long×9.5′ high structural steel base module. The foundation base module 1704 is positioned against the transverse concrete slab 1703, buy in some embodiments, a seal can be positioned between the base module 1704 and the slab 1703. Additional modules 104, such as a second or third module 104, can be stacked on top of the base module 1704 to achieve a desired height. Each stack can be oriented with the long dimension parallel to local flow of water. A water-retaining bulkhead 1502 can be affixed at the downstream face of the module stack 105. This configuration of the bulkhead 1502 affixed to the downstream face of the stack 105 allows the water to enter the modules 104 of the stack 105, and the weight of the entering water stabilizes the stack 105. Each stack 105 can be used to house systems such as turbine/generators, water release gates, etc., to create generation and passage modules (see
Each stack 105 in the SSPMH system 1100, 1800 can be tied into the riverbed through the foundation with, for instance, via a 3-inch diameter high strength steel rod that can be used as a post-tensioning anchor. The above-ground portion of the post-tension anchor can be extended with a coupler to capture and secure the intermediate and top modules 104. The post-tension anchor can be post-tensioned to a preload of approximately 600 kips and locked off against the top module frame to greatly increase downward force at the foundation interface and achieve the minimum factors of safety requirements for sliding, overturning, and uplift stability. The addition of a large knife valve or slide gate to the water-retaining bulkhead 1502 at the bottom of the foundation base module 1704 allows it to serve for low water passage and/or sediment passage.
Another benefit of utilizing knife valves or slide gates is they allow assembly in the wet without requiring any separate cofferdam or water control bypass systems. In simplified terms, the in-the-wet construction sequence is to first install the upstream and downstream sheet piles on one half of the river, and install an additional sheet pile line near the middle of the river in an orientation perpendicular to the first two lines of sheet piles and parallel to the river flow to bound the first working area. Water can be allowed to flow uninterrupted through the second half of the river, while the modules 104 are assembled in the bounded half. Once the assembly is complete, the knife valves or slides gates are left open and the sheet piles are cut down to the riverbed. Water begins to flow through the open structure. The process is repeated on the second half of the river. Once the entire modular facility is constructed appropriate knife valves or slide gates can be closed and the facility can be taken to operational status.
In an embodiment, abutment walls 1802 (in
A generation module stack (see
A water passage module stack (see
The SSPMH system 1100, 1800 can be designed around the principle of exclusion—that is, no fish are passed through the turbine runners—so as to avoid entrainment issues altogether. The modular powerhouse can be rotated to give rise to headpond flow diagonal to the turbine intakes and an approach velocity at the trash rack of under 2 fps. In this way the downstream fish migrants continue straight downstream and avoid the turbines altogether. At the downstream end of the powerhouse another module can be used to safely pass the fish (see
Overall stability of the system can be enhanced by utilizing the post-tensioned anchor to substitute for the mass of a traditional dam section. Typically, a dam relies on a substantial mass of concrete or earthen material to create a load normal to the foundation interface sufficient to engage enough friction to prevent the dam from sliding downstream due to the hydrostatic loading from the impoundment. The SSPMH system's modules 104 can be specifically designed to be relatively lightweight; therefore, another means can be used to resist sliding at the foundation interface, overturning and uplift. This stability is accomplished through the use of a tie-down anchor, which is bonded via grout to the foundation and locked off against the top module. The anchor assembly essentially squeezes the container-modules against the foundation.
The dam/foundation interface is important for dam stability; it provides surfaces with a high coefficient of friction to resist sliding, and appropriate stiffness to prevent differential settlement as between different parts of the foundation. The concrete segments/planks 1701 can be cast with a texture so as to maximize friction. Stiffness is obtained by the use of two layers of precast concrete planks connected with torqued slip-critical tension rods to obtain monolithic action.
The modules 104, 1704 themselves can be fabricated from 50 ksi hollow structural sections (HSS). The installation procedure can be summarized as follows. First, the foundation can be anchored on a coarsely leveled, competent subbase consisting of bedrock or coarse-grained soils. In either instance, for a low risk, safe installation the subbase area will need to be dewatered and prepared to receive the foundation's concrete segments/planks 1701. De-watering half the stream course at a time will allow preparation of the one half of the subbase in the dry and continuous stream flow around the dewatered half. The next step depends on riverbed conditions.
If the site is underlain by coarse-grained soils, the subbase is dewatered by driving interlocking steel sheet piles through these soils to refusal or bedrock. The piles extend from the upstream bank to the downstream bank in semi-circular fashion and extend high enough to prevent water from entering the dewatered area under normal flow conditions. Once the area has been prepared and the foundation base modules anchored in place, the piles are cut nearly flush with the bottom of the stream to return it to its full width. The portion of the piles that remain embedded in the coarse soils act as a barrier to minimize seepage beneath the foundation. This approach avoids the extra costs of a separate cofferdam. The opposite half of the stream course undergoes a similar process as above to prepare the remaining subbase. Low level outlet gates installed in the base container-modules of the first phase of construction are opened to pass the diverted stream flow through them.
If the site is underlain by bedrock, it is not possible to dewater the site using sheet piles. Instead, one half of the stream course may be dewatered using flexible intermediate bulk containers (FIBCS) filled with sand and installed in a semi-circular fashion. If necessary, steel plate can be sandwiched between the FIBCS to provide additional seepage control. The FIBCS are removed following placement of the first phase of modules and the process repeated on the opposite bank.
Either of the above construction processes ensures continuous flow of the stream course during construction and has minimal environmental impacts. In both instances, once both halves of the foundation base modules have been installed, the remaining assembly activities are performed with the stream course flowing normally through the low level outlets.
A water passage module stack (see
Typically, there will be some sediment buildup in the headpond, even in a pure run-of-the-river installation. Sediment can be passed at the base of each foundation base module 1704 through a water control element in the form of a knife valve or slide gate. An outlet orifice will be provided in the downstream bulkhead 1502 of each dam stack.
Periodic and programmatic opening of the gate under normal pool conditions will result in flow velocities to effectively flush sediment downstream to prevent erosion further downstream as well as for spawning. Periodic sluicing, flushing, or venting would maintain the bulk sediment transport regime averaged over the time between periodic sluicing/flushing/venting events.
With regard to constructing a prefabricated modular hydropower facility using shop-built components, the data that should be ascertained is the profile of the top 20-30 feet of geologic strata underneath a riverbed. Toward this end, the riverbed can be digitally profiled, and the foundation components can be pre-shaped using 3-D printing or computer controlled hot knife sculpting of polystyrene or other means to make mold inserts replicating the localized topographic conditions that the foundation blocks need to mate with. The precast elements can be sealed against the foundation, and in some cases, to shape the foundation. This technique may reduce the amount of site preparation and construction impact required to receive the modules and eliminate or reduce the need for chair jacks and the plank-leveling process steps.
In
An important function of the module stack assembly 1905 is to retain water to the necessary head elevation so the water may flow through the turbines in the module stacks as disclosed herein. It is important that the module stacks 1904, 1906 do not allow too much water to pass through the junctions where the modules come together and other mating locations, so the water is available to flow through the turbines and generate power. One characteristic of the invention that helps to prevent leakage is that the bulkheads 1502, whether on the downstream face as in
In one embodiment, a module stack assembly includes two vertical stacks where each vertical stack includes at least two modules. Seals similar to those discussed above may be horizontally installed between or covering over the junction between two vertical modules or vertically installed between or covering over the junction between two horizontal modules. The seals are configured to span across either horizontal or vertical joints between the modules, but not both. Thus, for two vertical stacks each with two modules, there may be three seals: two discrete horizontal seals, one each along the horizontal junction between each of the top and bottom modules, and one single vertical seal both covering the vertical junction and extending into the vertical junction, for example shaped like
In one embodiment, the three seals of the module stack assembly are configured to resist water leakage between the horizontal joints and the vertical joints such that the assembly 1905 has a leakage rate of much less than about 0.073 gpm per linear foot of seal, as evidenced in testing described below and as shown in Table 1 in the cell corresponding to the last row and second to last column.
In various embodiments, the modules are made of cast-in-place concrete with or without bar or fiber reinforcement. In various embodiments, the modules are made of precast concrete with or without bar or fiber reinforcement. In various embodiments, the modules are made of steel alloy, aluminum alloy, glass fiber reinforced plastic or carbon reinforced plastic. In various embodiments, the modules are made of a hybrid or combination of any two or more of the above materials.
In operation, the modules need not be completely watertight. There are no established engineering association standards for calculating leakage through modular dams at hydropower facilities. However, there is some guidance in the American Water Works Association for Fabricated Stainless Steel Slide Gates (AWWA C561) and for Fabricated Case Iron Slide Gates (AWWA C560) specifications. These specifications state that with respect to seating head for these gates, leakage shall not exceed 0.1 gpm of leakage per linear foot of seal. Applying this specification to an SSPMH facility results in a barely perceptible impact on power generation as shown in the following calculations.
Assumptions: (a) leakage at all seals shall not exceed 0.1 gpm per lineal foot of seal, (b) calculation based on a three-module stack such as shown in
Calculations: (a) seal joint location and wet length—(i) module stack side-to-side vertical joint (one side), length=28.5−2.2=26.3 ft, (ii) module-to-module top-to-bottom horizontal joint, length=8 ft per joint×2 joints=16 ft, (iii) bottom module to foundation horizontal joint, length=8 ft and (iv) total wet seal length=26.3+16+8=50.3 ft; (b) total leakage at seals per stack—(i) total leakage=total seal length×unit leakage=50.3 ft×0.1 gpm/ft=5.03 gpm per module stack and (ii) 1 cfs=448.8 gpm, 5.03 gpm×1 cfs/448.8 gpm=0.0112 cfs, resulting in leakage rate of about 0.0112 cfs per stack.
Significance of leakage with respect to power generation: (i) assume a hydropower facility made up of 21 module stacks including 9 stack assemblies with a turbine generator, (ii) leakage of about 0.0112 cfs per stack assembly×21 stacks=0.235 cfs for the facility, (iii) hydraulic flow through the turbines for power generation is 9 turbines×100 cfs/turbine=900 cfs, (iv) leakage impact on generation flow=leakage/hydraulic capacity=0.235 cfs/900 cfs=0.000261, i.e., 0.026%, and (v) in the case where the hydropower project could tolerate 0.1% of generation flows being lost to leakage, then a leakage criterion of 0.1/0.026×0.1 gpm/ft=0.385 gpm/ft would be acceptable.
The calculation above includes leakage at seals, not through the modules, since the modules fabricated as described herein are unlikely to contribute to leakage. For modules where the structural framework 104 is fabricated from structural steel with welded bulkheads 1502, the welded joints are a potential source of leakage. In some embodiments, the seams and joints may be seam welded by certified welders, and in accordance with the latest standards of the American Welding Society (AWS) and American Institute of Steel Construction (AISC). In addition, one or more of the inspection techniques may be utilized, including 100% visual inspection, air pressurize bubble test with soap spray, or water spray test for liquid-tight welds. As a results, leakage through the framework 104 or bulkheads 1502 for a welded steel assembly is not a significant source of leakage. All or part of the structural framework 104 and bulkheads 1502 could be fabricated from structural fiber reinforced plastic (FRP) composites using glass, carbon, aramid or any other suitable structural fiber or hybrids of various fiber reinforcements for hydropower projects where FRP corrosion resistance and strength to weight ratios are a benefit warranting the extra cost. For example, in projects located in brackish water or in remote locations where weight driven transport costs are significant. Composites are known to absorb water in the polymer resin matrix, but it is an insignificant amount with respect to leakage especially if fabricated to water storage standards such as, for example, BS EN 13280:2001 “Specification for glass fiber reinforced cistern of one-piece and sectional construction, for the storage, above ground, of cold water.”
In some embodiments, the modules could include precast concrete elements such as ground anchors 206, the foundation elements shown in
The junctions where modules come together are the prime locations for leakage in modular dams and hydropower facilities. Sealing these joints in a way that the modules can be disassembled for repair, replacement or reuse at the same or different site is not a simple manner of neoprene gaskets. There are some specific seal material properties, relative dimensions and placements that make for successful low leakage modular dam and hydropower facility.
The seals between the modules and between the modules and the foundation are specified to meet certain leakage criteria. Testing apparatus and testing methods that can be used to verify the performance and provide test data to define a range of material properties and relative geometry for successful non-leakage performance will be described further in more detail below.
The ratio between the thickness T of the horizontal seal 2100, as shown in
As best illustrated in
As best illustrated in
As best illustrated in
As best illustrated in
While the seals 2100, 2400 and the end caps 2200, 2300 discussed above are with respect to vertical or horizontal module stacks, it will be understood and appreciated by one skilled in the art that the seals 2100 and 2400 end caps 2200, 2300 may be used interchangeably with appropriate modification. In other words, vertical seals 2400 may be used as horizontal seals 2100, and vice versa. Similarly, the end caps 2200, 2300 may also be used interchangeably for integration of the module stacks. To interchange them one must appreciate that the horizontal seals 2100 rely on the compression achieved by the weight of the modules 104 and the force exerted by the module integration rod 1910 to complete an effective seal against water leakage. Horizontal seals may be used as vertical seals if sufficient horizontal clamping force is provided between the stacks. Whereas the vertical seals 2400 rely on the pressure from the water to achieve the seal. For vertical seals used in the upstream position
In one embodiment, a system 100 includes a plurality of modules 104, 1904 assembled to form at least one stack 105, 1905. In this embodiment, the at least one stack includes vertical seals similar to seals 2100, 2400, whereby the vertical seals are installed vertically between each of the plurality of modules 104, 1904. In another embodiment, the at least one stack includes horizontal seals similar to seals 2100, 2400, whereby the horizontal seals are installed horizontally between each of the plurality of modules 104, 1904. In operation, the vertical seals and the horizontal seals are configured to prevent leakage and provide near water-tight connection.
In one embodiment, each of the vertical seals described above may include at least one protruded section similar to the protruded sections 2110, 2410. Likewise, in another embodiment, each of the horizontal seals may include at least one protruded section similar to the protruded section 2110, 2410. In some embodiments, the system 100 may further include a post-tension anchor 1202 securing the at least one stack 105, 1905 to a foundation.
In operation, a collection of one or more integration parts such as those described above, e.g., module integration rod 1910, male end cap 1920, horizontal seal 2100, female end cap 2200, and vertical seal 2400, can help to provide better sealing capabilities than previously known sealants for the module stacks.
Since the SSPMH is innovative, there is no existing testing standard that is applicable to testing leakage through the seals. There is some general guidance from ANSI/FM Approvals 2510, which is a standard stating the examination and test requirements for flood mitigation equipment. Accordingly, disclosed herein according to an embodiment is a test method to expose true-scale SSPMH module junctions having vertical and horizontal seals to operational-level head pressures, observe and measure the leakage through the seals, compare the leakage rates against the selected standards, and use the information gained to confirm or modify the seal design.
In one embodiment, the test apparatus 2500 includes four components: a test tank 2520 (as best illustrated in
In one embodiment, as shown in
The test fixture 2530 as illustrated in
In operation, a method of using a test apparatus according to an embodiment includes: (a) assemble a test tank 2520, (b) attach a test fixture 2530 with seals, (c) attach a stand pipe 2510 to the test tank 2520, (d) fill the stand pipe 2510 with water, (e) observe and photograph results, (0 collect water (if any) that leaks out and is caught in a catch basin (not shown), (g) continue collection step (0 and weigh the water in the catch basins every 30 minutes, (h) report weight and volume of water collected, (i) calculate and report leakage rate in gallons per minute per linear foot of seal (gpm/lf), (j) compare result to the leakage standard of 0.10 gpm/lf.
Table 1 below summarizes a variety of module-to-module seal configurations and their effectiveness at resisting leakage as evaluated using the test apparatus and methods described above. The seals in seal sets A-1 and A-2, rows 1-4 of Table 1, represent the standard approach for sealing flat plates; flat pieces of neoprene as specified in column 3 of Table 1 with the dimensions presented in columns 5-8 of Table 1 were sandwiched between module beams in horizontal and vertical locations where the water was expected to flow through. In this test series the standpipe 2510 was filled to achieve 15 feet 10 inches of water height including the depth of the test tank 2520. Test of the A series of seals resulted in substantial observed leakage that did not, by inspection, meet the selected leakage standard of a maximum of 0.10 gpm/lf. High volume, high velocity leakage was observed particularly at the intersections of the neoprene seals and steel spacer plates and alignment cones. Based on visual inspection, the seals in A-2 performed moderately well. Because the test apparatus collects the water that leaks out of the entire test fixture 2530 seal system it is not possible to isolate a quantitative leakage rate of the A-2 seals from the A-1 seals, but visually one could observe that the leakage from the A-2 seal area was characterized by small rivulets near interfaces as opposed to fast streaming water leaking out near the A-1 seals. The A-2 seal is a soft material, 30-durometer, that is easier to extruded into spaces, grooves, and gaps than the harder, 50-durometer, material used in the A-1 seals, which explains its somewhat better sealing ability.
Test 2 used horizontal seal set B. The B seals were 1 inch thick and included a straight section 3 inches wide and an end wrap section ⅞ inch wide in the shape represented by half of the length of the image shown in
Test 3 also used horizontal seal set B, but used vertical seals, B-2, that were characterized by a “T” shape with a flange and protrusion as shown in
″ ID gap
indicates data missing or illegible when filed
Seals for modular dam or hydropower facility and test results.
As a result of the test apparatus and test method, the following guidelines can be used for specifying seal geometry and material properties for module-to-module seals for modular dams or hydropower facilities according to the present disclosure.
In one embodiment, there are observations of leaks at interfaces between the seals and steel plates that appear to be caused by a flow path between seal and steel plate ends. Proposed solution includes combining spacers and shims, among others, to reduce the number of interfaces in the seal area, place seal material upstream of plates and shims as much as possible, and make seals as a single piece to eliminate joints, to name a few.
In one embodiment, there are observations of leaks over the surfaces of steel plates, but not when there is a thin, soft gasket placed on the surface of the steel plate, which may be caused by flow path across steel-on-steel contact surfaces. Proposed response includes use of thin, soft (e.g., less than 50-durameter, 30-durameter preferred) neoprene on top and bottom of any steel spacer/shim plates, to name a few.
In one embodiment, there are observations of high torque on through bolts needed to compress horizontal seals, which appear to be caused by stiff horizontal seals with large surface area thus lowering unit area stress and effectiveness. Proposed response includes reducing width of horizontal seal strip to less than half of the beam width, and reducing stiffness of horizontal seal neoprene material to less than 50-durometer, to name a few.
In one embodiment, there are observations of leakage in the vertical joint, which may be caused by difficulty in adequately compressing neoprene in vertical joints. One solution includes redesigning vertical joint seal by: redundant sealing system, “T-seal” configuration, hollow bulb seal in vertical joint, neoprene flange with knobs for sealing against downstream face or provide seal compression/confinement with downstream backer plate. Alternative solution includes redesigning vertical joint seal by: redundant sealing system, independent hollow cylinder strip seal in vertical joint, provide seal compression/confinement with downstream backer plate, twin O-ring stock seal lines (each) side seated in backer plate to seal against downstream face, and hydrophilic “swell stop” water stop strip on each side seated in backer plate to seal against downstream face and confined by O-ring stock seals, to name a few.
In one embodiment, observations of leakage at four corner intersection appear to be caused by seals not continuous through the corners. Proposed response includes making vertical seal continuous across corner intersection, to name a few.
In one embodiment, observations of potential flow path through corner block holes may be caused by direct flow path through corner block side and to/bottom holes to downstream end hole. Proposed solution includes eliminating side and downstream end corner block holes, to name a few.
In one embodiment, observations of potential for change in vertical joint width due to thermal expansion/contraction appear to be caused by change in width of adjacent modules due to thermal expansion/contraction of steel. Proposed responses include: (a) calculating potential change in joint width: (i) coefficient of Thermal Expansion for MOO, Grade B, 46 ksi steel=6.7×10−6/Deg. F, (ii) module nominal width=8.0 feet, (iii) assume±50 Deg. F. change in temp possible from initial install, and (iv) 8 ft×6.7×10−6/Deg. F×50°=0.0027 ft.=0.0322 in.=− 1/32″; and (b) redesigning vertical seal to accommodate change in joint width through: (i) oversizing vertical neoprene seal in joint to accommodate expansion, (ii) provide hollow vertical neoprene seal in joint to accommodate compression, and (iii) provide oversize (oval) backer plate bolt holes to accommodate movement, to name a few.
In one embodiment, observations of vertical seals that are hard to replace particularly during module replacement may be caused by limited access after the modules are in place or seals that are hard to install during module replacement. Proposed responses include redesigning vertical seals for access from downstream end or redesigning vertical seals for installation after modules are in place, to name a few.
In one embodiment, design issues related to manufacturing tolerances may be resolved by sizing and configuring horizontal seals to provide for slight space around steel plates and being prepared to trim seals if needed, to name a few.
In one embodiment, design issues related to possible tearing of neoprene seals at corners may be resolved by rounding internal return corners of horizontal seals to prevent stress concentrations and rounding corners of steel spacer/shim plates to prevent cutting, to name a few.
While example embodiments have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the embodiments encompassed by the appended claims. For example, other useful implementations could be achieved if steps of the disclosed techniques were performed in a different order and/or if components in the disclosed systems were combined in a different manner and/or replaced or supplemented by other components. Accordingly, other implementations are within the scope of the disclosure.
This application is a continuation-in-part (CIP) of U.S. patent application Ser. No. 18/151,995, filed Jan. 9, 2023, which is a continuation of U.S. patent application Ser. No. 16/883,970, filed May 26, 2020, which claims the benefit of U.S. Provisional Patent Application No. 62/852,066, filed May 23, 2019, the disclosures of each of which are incorporated by reference, in their entirety.
This invention was made with government support under DE-EE0007243 awarded by the Department of Energy. The government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 62852066 | May 2019 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16883970 | May 2020 | US |
| Child | 18151995 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 18151995 | Jan 2023 | US |
| Child | 18366372 | US |
