Injection molding screening apparatus and method

Abstract

A screen assembly is formed by attaching side edges of a plurality of screen elements to each other. The reinforcing fibers may be embedded in the material of the selected screen element. The reinforcing fibers extend in a direction in which the screen assembly is to be tensioned to secure the screen assembly to the screening machine. The hook strip may be attached to an end or side of the screen assembly to facilitate mounting the screen assembly to a screening machine.

Description

This application is a divisional application of the application with the application number 202380032766.5, the filing date of April 6, 2023, and the invention name of "Injection Molding Screening Equipment and Method". Cross - reference to related applications

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 328,228, filed on April 6, 2022, the entire content of which is incorporated herein by reference and claims its priority. Technical Field

[0002] The present disclosure generally relates to material screening. More specifically, the present disclosure relates to screening members, screening assemblies, methods of manufacturing screening members and screening assemblies, and methods of screening materials. Background Art

[0003] Material screening includes the use of vibrating screening machines. A vibrating screening machine provides the ability to excite an installed screen such that materials placed on the screen can be separated to a desired level. Oversize materials are separated from undersize materials. Over time, the screen wears and needs to be replaced. Thus, the screen is designed to be replaceable.

[0004] The replacement screen assembly must be firmly fixed to the vibrating screening machine and withstand significant vibratory forces. The replacement screen can be attached to the vibrating screening machine by a tensioning member, a compression member, or a clamping member.

[0005] In the past, screen assemblies were made of metal and / or thermosetting polymers. The materials and structures of the screen assemblies are specific to the screening application. For example, due to the relative durability and fine screening ability of metal screens, metal screens are often used in wet applications in the oil and gas industry. Traditional thermosetting polymer - type screens can also be used in wet and dry screening applications.

[0006] Manufacturing thermosetting polymer - type screens is relatively complex, time - consuming, and error - prone. A typical thermosetting polymer - type screen used with a vibrating screening machine is manufactured by mixing separate liquids (e.g., polyester, polyether, and a curing agent), and then filling a screen mold with the mixed liquid. These liquids undergo a chemical reaction and curing in the mold over a period of time. Once cured, the screen is then removed from the mold. The curing time in the mold is typically measured in hours. In some cases, it may take ten hours or more before the screen is fully cured enough to be removed from the mold.

[0007] When it is desired to manufacture a screen having both fine holes and a relatively large open screening area, it is necessary to make the screening surface elements quite fine. The screening surface elements are the solid portions between the openings of the screen. In some cases, it is necessary to manufacture such a screen such that the thickness or width dimension of the screening surface elements is as small as 40 - 100 microns. This means that the channels in the mold must also have a width or diameter of 40 - 100 microns. It is difficult and time-consuming to ensure that the liquid mixture used to form the screen completely fills all the very small voids and channels in the mold. Doing so may require special movements, high pressures, and complex processing procedures.

[0008] Typically, the liquid used to form the screen does not reach and fill all the cavities in the mold. A defect in the resulting screen (e.g., a hole where the liquid did not reach) will ruin the entire screen. Additionally, when the screen is removed from the mold, a small tear or break will also damage the screen. This is especially problematic when making relatively large screens (e.g., 2 feet by 3 feet or larger), and a single small flaw can ruin the entire screen.

[0009] When considering the manufacturing process for making thermoset screens, the curing time is the longest and is generally a limiting factor in terms of productivity. The curing time is similar whether making small or large screens. Thus, it hardly makes sense to manufacture multiple small thermoset screens and then spend additional time joining the small thermoset screens together to make a larger thermoset screen assembly. Instead, it makes sense to simply manufacture the thermoset screen in the actual desired size, as this allows for the fastest productivity.

[0010] Furthermore, traditional cast thermosetting plastics cannot be melted or reformed after curing. For this reason, it is difficult to join multiple smaller thermoset screens together to make a larger thermoset screen assembly. This is another reason why those skilled in the art tend to simply manufacture the thermoset screen in the desired size rather than manufacturing multiple smaller thermoset screens and then assembling them together to make a larger thermoset screen assembly.

[0011] Thermoset polymer screens are relatively flexible and are typically fixed to a vibrating screen machine using tensioning members that pull the side edges of the thermoset polymer screen apart from each other and secure the bottom surface of the thermoset polymer screen to the surface of the vibrating screen machine. To prevent deformation during stretching, the thermoset polymer assembly can be molded with aramid fibers extending in the direction of stretch (see, for example, U.S. Patent No. 4,819,809). If compressive forces are applied to the side edges of a typical thermoset polymer screen, it may bend or curl, rendering the screening surface relatively ineffective. However, the thermoset polymer screen can be attached to a rigid plate or subassembly, allowing the thermoset polymer screen to be used in compression-mounted applications.

[0012] In contrast to thermoset polymer screens, metal screens are rigid and can be compressed or stretched onto a vibrating screen machine. Metal screen assemblies are typically made from a variety of metal components. The manufacture of metal screen assemblies generally includes manufacturing the screening material, typically using multi-layer woven wire mesh. In some cases, such as when the screen assembly is to be used in a compression-mounted application, the manufacturing process can further include manufacturing a perforated metal backing plate and bonding the screening material to the perforated metal backing plate. The layers of wire cloth can be finely woven to have openings in the range of approximately 30 microns to approximately 4000 microns. The entire screening surface of a conventional metal assembly is typically a relatively uniform planar structure or a relatively uniform corrugated structure.

[0013] Critical to the screening performance of the screen assemblies (thermoset polymer assemblies and metal-type assemblies) of vibrating screen machines are the opening size in the screening surface, the structural stability and durability of the screening surface, the structural stability of the entire unit, the chemical properties of the unit components, and the ability of the unit to operate under various temperatures and environments. Disadvantages of conventional metal assemblies include a lack of structural stability and durability of the screening surface formed by the woven wire mesh layers, screening surface clogging (particles blocking the screen holes), the weight of the entire structure, the time and cost associated with the manufacture or purchase of each component part, and the assembly time and cost. Since wire cloth is typically outsourced by screen manufacturers and is often purchased from weavers or wholesalers, quality control can be extremely difficult and problems with wire cloth frequently occur. Defective wire cloth can cause screening performance problems and thus requires continuous monitoring and testing.

[0014] One of the biggest problems with traditional metal components is blinding. New metal screens may initially have a relatively large open screening area, but over time, as the screen is exposed to particles, the screen openings become blocked (i.e., blinded), and the open screening area and the effectiveness of the screening itself decrease relatively quickly. For example, a 140-mesh screen assembly (with three layers of screen) can have an initial open screening area of 20 - 24%. However, as the screen is used, the open screening area can decrease by 50% or more.

[0015] Traditional metal screen assemblies also lose a significant amount of open screening area due to their structure, which includes adhesives, backing plates, plastic sheets that bond the layers of wire cloth together, etc.

[0016] Another major problem with traditional metal components is screen life. Traditional metal components typically do not fail due to wear, but rather due to fatigue. That is, the wires of the woven wire cloth actually often break due to the up and down movement they experience during vibratory loading.

[0017] The disadvantages of traditional thermoset polymer screens also include a lack of structural stability and durability. Additional disadvantages include an inability to withstand compressive-type loads and an inability to withstand high temperatures (e.g., typically thermoset polymer-type screens will begin to fail or exhibit performance problems at temperatures above 130°F, especially screens with fine pores (e.g., approximately 43 microns to approximately 100 microns)). In addition, as mentioned above, the manufacturing process is complex, time-consuming, and error-prone. Moreover, the molds used to manufacture thermoset polymer screens are expensive, and any flaw or minor damage will ruin the entire screen and require replacement, which can result in costly downtime during the manufacturing process.

[0018] Another disadvantage of traditional metal and thermoset polymer screens is the limitation of the existing screening surface structure. Whether the screening surface is flat or undulating, the existing screening surfaces are manufactured to have relatively uniform opening sizes and relatively uniform surface structures.

[0019] There is a need for general and improved screening elements, screening assemblies, methods of manufacturing screening elements and screening assemblies, and methods of screening materials for vibratory screening machines that incorporate the use of injection-molded materials (such as thermoplastics) with improved mechanical and chemical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A An injection-molded thermoplastic screen element according to an embodiment is shown.

[0021] Figure 1B An injection-molded thermoplastic screen element according to an embodiment of Figure 1A is shown in detail.

[0022] Figure 2 Shows a plurality of injection - molded thermoplastic screen elements coupled to each other according to an embodiment to form a screen assembly.

[0023] Figure 3 Shows a plurality of injection - molded thermoplastic screen elements coupled together with each other according to an embodiment to form a screen assembly.

[0024] Figure 4 Shows a thermoplastic screen assembly formed by coupling a plurality of injection - molded thermoplastic screen elements to each other according to an embodiment.

[0025] Figure 5A Shows an isometric bottom view of a screen assembly with reinforcing fibers embedded therein for front - to - back tension application according to an embodiment.

[0026] Figure 5B Shows Figure 5A an isometric top view of the screen assembly.

[0027] Figure 6 Is an isometric bottom view of a screen element having a molded recess for receiving reinforcing fibers.

[0028] Figure 7A Is a perspective view showing how two connected strips of screen elements can be joined together with reinforcing fibers sandwiched between the strips of screen elements.

[0029] Figure 7B Shows Figure 7A the two strips of screen elements after the strips of screen elements are joined together.

[0030] Figure 8 Shows an isometric top view of a screen element having a reinforcing member extending downward along the middle of the length of the screen element.

[0031] Figure 9 Shows an isometric top view of a screen assembly with continuous reinforcing fibers embedded therein according to an embodiment.

[0032] Figure 10 Shows an isometric view of a screen assembly with a hook strip according to an embodiment.

[0033] Figure 11 Shows a side view of a screen assembly with a hook strip according to an embodiment.

[0034] Figure 12A Shows an image of an experimental screen assembly according to an embodiment.

[0035] Figure 12BShows an image of an experimental screen assembly according to an embodiment.

[0036] Figure 13 Shows a top view of a screen assembly with a boundary according to an embodiment.

[0037] Figure 14 Shows according to an embodiment Figure 13 detailed view of the screen assembly of.

[0038] Figure 15 Shows a top view of a screen assembly with a boundary according to an embodiment.

[0039] Figure 16 Shows according to an embodiment Figure 15 detailed view of the screen assembly of, in which the reinforcing fibers are omitted.

[0040] Figure 17A Shows two screen elements with a first design facilitating connection of the side edges.

[0041] Figure 17B Shows two screen elements with a second design facilitating connection of the side edges

[0042] Figure 18 Shows the steps of a first method of manufacturing a screen assembly according to an embodiment.

[0043] Figure 19 Shows the steps of a second method of manufacturing a screen assembly according to another embodiment.

[0044] Figure 20A and 20B Shows a seam between two adjacent screen elements, the seam including a protruding portion formed along the seam.

[0045] Figure 21 Is a top view of a support plate that can be incorporated into a screen assembly.

[0046] Figure 22 Is a cross-sectional view of a part of a screen assembly including a support plate.

[0047] Figure 23 Is a cross-sectional view of a part of a screen assembly including a corrugated structure.

[0048] Figure 24A Shows side views of two different types of screen elements that can be connected together to form a screen assembly with a crest structure or a corrugated structure.

[0049] Figure 24B Shows as Figure 24A shown multiple screen elements after connection to form a screen assembly with a crest structure.

[0050] Figure 25 is a perspective view of a screen assembly including a support plate and a screen layer of interconnected screen elements, the screen layer being formed with a corrugated structure. DETAILED DESCRIPTION

[0051] Embodiments of the present invention provide a screen assembly including injection molded screen elements. The injection molded screen elements provide a number of advantages in screen assembly manufacturing and vibratory screening applications. In certain embodiments of the present invention, a thermoplastic material is used to injection mold the screen elements. The individual screen elements are attached together to form a larger screen assembly. This allows one to manufacture screen assemblies of almost any size or shape from a plurality of smaller screen elements.

[0052] In many of the examples below, the screen elements are square or rectangular. However, the screen elements can be triangular, trapezoidal, circular, or almost any other shape. The screen assembly can be formed by attaching together a plurality of screen elements of the same size and shape. Optionally, a screen assembly can be manufactured by attaching together a plurality of screen elements where the screen elements have different sizes and / or different shapes.

[0053] Generally, the larger the screen element, the easier and faster it is to assemble a complete vibratory screen assembly. However, the larger the screen element, the more difficult it is to injection mold very small structures, i.e., the structures that form the screening surface elements between the screen apertures. The screen elements are designed to be large enough to effectively assemble a complete screen assembly structure, but small enough so that the screen elements can be quickly injection molded.

[0054] The size of an individual screen element can also be affected by the desired characteristics of the screen element or the final screen assembly. For example, when one attempts to form a screen assembly where the screening surface elements have very fine dimensions (e.g., 40 - 100 microns wide), the channels in the injection mold used to manufacture the screen element must have correspondingly narrow dimensions. Injecting a plastic material or a synthetic material into such a mold such that the injected material completely fills the cavity of the mold before becoming solid can be difficult, especially if the distance the material must travel in the mold is large. For this reason, in some cases, it makes sense to keep the overall size of the mold and the corresponding screen element fairly small, which keeps the plastic injected into the mold from having to travel too far in the mold during the molding process. This ensures that the plastic completely fills the cavity in the mold before curing.

[0055] The need for large screen elements and the need to form very fine screening surface elements can be balanced by using a mold with a relatively small first dimension and a relatively large second dimension, such as a rectangular mold. The material can then be injection molded into the mold such that the material passes through channels in the mold in the direction of the small dimension. This results in the material traveling a short distance through the mold, which helps to ensure that the cavities of the mold are completely filled before the material solidifies.

[0056] As long as the overall dimensions of the screen element remain relatively small, it is possible to form screen elements by injection molding, where these screen elements have very thin or narrow screening surface elements such that the screen element has a high open screening area. For example, a screen element that may be formed has a screening surface element that is 40 - 100 microns in width or thickness. Such a screen element can exhibit an open screening area that is 15 - 40% of the total screening area.

[0057] The open screening area is an important characteristic of a vibrating screen assembly. Before the screen is put into use, the average available open screening area of a conventional wire mesh screen assembly of 100 to 200 mesh (i.e., the actual open area considering the structural steel of the support members and the bonding material) may be relatively high. However, conventional wire mesh screens quickly become clogged during actual use, which results in a rapid decrease in the actual open screening area. It is not uncommon for a conventional metal screen to become clogged and reduce the actual open screening area by 50% within the first 24 hours of use. In contrast, plastic or synthetic screen elements formed by injection molding tend not to clog and can provide a much higher open screening area value over a longer period of time.

[0058] Conventional wire assemblies also often fail due to the wire being subjected to a vibratory force that exerts a bending load on the wire. In contrast, according to embodiments of the present invention, injection molded screen assemblies rarely fail due to a loss of structural stability. In fact, the screen assemblies according to embodiments of the present invention have a very long lifespan and can last for a long time under heavy loads. The screen assemblies according to the present invention have been tested under rigorous conditions for several months without failure or clogging, while conventional wire assemblies tested under the same conditions became clogged and failed within a few days.

[0059] In embodiments of the present invention, thermoplastics are used for injection molding the screen elements. Contrary to thermosetting polymers that include liquid materials that chemically react and cure at a temperature, the use of thermoplastics is generally simpler and can be provided by, for example, melting a homogeneous material (usually in the form of solid particles) and then injection molding the molten material. Not only are the physical properties of thermoplastics optimal for vibrating screen applications, but the use of thermoplastic liquids provides an easier manufacturing process, especially when dealing with micro-molded components as described herein.

[0060] Forming the screen element using a thermoplastic material provides a screen assembly that exhibits excellent flexural and flex fatigue strength. Thermoplastics are an ideal choice for components that are subject to intermittent or continuous heavy loads, such as those encountered by vibrating screens used on vibrating screen machines. Because the vibrating screen machine undergoes motion, the low coefficient of friction of thermoplastic injection molding materials provides optimal wear characteristics. In fact, the wear resistance of certain thermoplastics is superior to that of many metals. In addition, due to their toughness and ductility characteristics, the use of the thermoplastics described herein provides the best material for manufacturing "snap-fit connections". The use of thermoplastics in embodiments of the present invention also provides resistance to stress cracking, aging resistance, and resistance to extreme weathering.

[0061] The heat distortion temperature of the thermoplastic can be in the range of 200°F. With the addition of glass fiber, this temperature can be increased to about 250°F to 300°F or higher. The introduction of glass fiber or carbon fiber can also increase the rigidity measured by the flexural modulus, which increases from about 400,000 PSI to more than about 1,000,000 PSI. All of these characteristics are ideal for the environment encountered when using a vibrating screen on a vibrating screen machine under harsh conditions in the field.

[0062] Depending on the desired characteristics of the embodiment, various materials can be incorporated into the screen element. Thermoplastic polyurethane (TPU) can be incorporated into the embodiment to provide elasticity, transparency, and resistance to oil, grease, and wear. TPU also has high shear strength. These characteristics of TPU are beneficial when applied to embodiments that will be subject to high vibration forces, abrasive materials, and high load demands. Depending on the material being screened, different types of TPU can be incorporated into the embodiment. For example, polyester-based TPU can be incorporated into a screen assembly for oil screening and / or gas screening because esters provide excellent wear resistance, oil resistance, mechanical integrity, chemical resistance, and adhesion strength. Polyether-based TPU can be used in mining applications where hydrolysis resistance (a property of polyether-based TPU) is important. The materials used for the embodiment can be selected or determined based on various factors, including the properties of each material and the cost associated with using these materials.

[0063] The material used to form the screen element can be selected to have high temperature resistance, chemical resistance, hydrolysis resistance, and / or wear resistance. The screen element can incorporate a material such as TPU to provide a transparent appearance to the screen element. For the purpose of laser welding, the transparent screen element can allow effective laser transmission through the screen element.

[0064] Embodiments of a screen assembly formed from a number of individually injection molded thermoplastic screen elements are disclosed, which are joined together, for example, by thermoplastic welding or other means to form a large screening surface. In some embodiments, reinforcing fibers can be added to the structure to provide increased strength, particularly tensile strength. The reinforcing fibers can be fibers or filaments that are partially or fully embedded in the screen element material. Such reinforcing fibers can help the screen assembly withstand the tensile loads imposed by the mounting elements used to secure the screen assembly to a vibrating screen.

[0065] As described above, a number of small screen elements can be formed by casting a thermosetting material in a mold. These thermosetting screen elements can then be attached to each other by fasteners or adhesives to form a larger screen assembly. However, this method has a number of drawbacks that make it unattractive, particularly when compared to screen elements made by injection molding thermoplastics.

[0066] For example, the time required to cast a small screen element from a thermosetting material is measured in hours. In contrast, small screen elements can be formed by injection molding thermoplastics in a matter of seconds.

[0067] In addition, once a screen element has been cast from a thermosetting material, it is no longer possible to remelt or reshape the screen element. Therefore, the only way to attach multiple thermosetting screen elements together is by using adhesives or mechanical fasteners.

[0068] In contrast, injection molded thermoplastics and injection molded thermoplastic screen elements can have their edges remelted and welded together. Strong bonds can be formed between individual injection molded thermoplastic screen elements using welding and other thermal and non-thermal techniques, all of which do not require the use of adhesives or mechanical fasteners. Thermal welding, friction stir welding, and ultrasonic welding techniques can be used to join multiple individual injection molded thermoplastic screen elements together to form a large screen assembly.

[0069] The remelting characteristics of injection molded thermoplastics also allow for the easy addition of reinforcing fibers to the thermoplastic screen assembly. This can be accomplished by remelting a selected portion of the thermoplastic material of the screen assembly and inserting the reinforcing fibers into the molten portion of the thermoplastic screen assembly. Additionally, as described below, two or more thermoplastic screen elements can be joined together by melting the side edges of the screen elements, bringing the side edges together, and then allowing the molten portion to cool and solidify. When this process is carried out to fasten multiple thermoplastic screen elements together to form a larger screen assembly, one or more reinforcing fibers can be positioned between the molten side edges of the thermoplastic screen elements as the screen elements are brought together. This causes the position of the reinforcing fibers between the individual screen elements to be encapsulated into the larger structure during the process of fastening the screen elements together.

[0070] After a thermoset screen element is formed, it is nearly impossible to incorporate reinforcing fibers into the material of the thermoset screen element. Therefore, it is also impossible to add reinforcing fibers to a screen assembly formed from thermoset screen elements. The only way to introduce reinforcing fibers into a thermoset screen element is to insert the reinforcing fibers into the mold before introducing the thermosetting material. While this may get the reinforcing fibers into an individual thermoset screen element, it is not possible to get individual reinforcing fibers through the entire structure of multiple thermoset screen elements if the multiple thermoset screen elements are joined together to form a larger screen assembly. For all of these reasons, it is not possible to effectively add reinforcing fibers to a screen assembly composed of multiple thermoset screen elements in the same manner as for thermoplastic screen elements.

[0071] Systems and methods for forming large thermoplastic screen assemblies utilizing the melting characteristics of injection molded thermoplastics are described below. These systems and methods can include incorporating reinforcing fibers into the material of the screen elements that make up the screen assembly.

[0072] Figure 1A and Figure 1B An injection molded thermoplastic screen element 10216 is shown having generally parallel ends 10220 and generally parallel sides 10222 that are generally perpendicular to the ends 10220. As Figure 1B shown, the screening surface 10213 includes surface elements 10284 that extend parallel to the sides 10222 and form screening apertures 10286. Each screen element 10216 is a single thermoplastic injection molded piece.

[0073] As Figure 1BAs shown, the surface element 10284 has a thickness T that extends between adjacent screening apertures 10286, and this thickness can vary depending on the screening application and the configuration of the apertures 10286. Depending on the embodiment, T can be, for example, from about 10 microns to about 4000 microns. Depending on the width W of the apertures 10286, forming a screening surface element 10284 with a thickness T between 50 - 150 microns can provide a screening surface with a desirable high open screening area value. The apertures 10286 are elongated slots having a length L and a width W, and their length and width can vary according to the selected structure. The width W can be the distance between the inner surfaces of adjacent screening surface elements 10284 of from about 10 microns to about 6000 microns. In some embodiments, the width W can be the distance between the inner surfaces of adjacent screening surface elements 10284 of from about 25 microns to about 2000 microns. The apertures 10286 do not need to be rectangular, but can be any shape suitable for a particular screening application formed by thermoplastic injection molding, including approximately square, circular, and / or elliptical, as described herein.

[0074] The screen elements can be made of various materials depending on the desired characteristics of the final screen assembly. Thermoplastic polyurethane (TPU) can be incorporated into embodiments of the screen elements and screen assemblies to provide elasticity, transparency (when helpful or necessary), as well as water resistance, resistance to chemicals with different pH values, oil resistance, grease resistance, and abrasion resistance. TPU also has high shear strength. These properties of TPU are beneficial when applied to embodiments of screen elements and screen assemblies that are subjected to high vibratory forces, abrasive materials, and high load demands.

[0075] The material for the screen elements used to form the screen assembly can be selected to have high temperature resistance, chemical resistance, hydrolysis resistance, and / or abrasion resistance. The screen elements can incorporate a material such as TPU to provide a transparent appearance for the screen elements. For the purpose of laser welding, the transparent screen elements can allow effective laser transmission through the screen elements. However, in the case where laser welding is not used, the screen elements can be opaque and / or colored. Various different colorants can be added to the TPU material to produce screen elements of different colors, where the color can indicate various properties of the screen elements. For example, a first color can be used for screen elements having apertures of a first size, and a second color can be used for screen elements having apertures of a second different size.

[0076] Figure 2 Shown is how multiple injection - molded thermoplastic screen elements 10216a, 10216b, 10216c are coupled to each other along seams 10310 to form part of a screen assembly. The multiple injection - molded thermoplastic screen elements 10216 can be combined, joined, or otherwise coupled together in a variety of ways.

[0077] In some embodiments, thermoplastic screen elements can be joined together by welding, where two or more thermoplastic screen elements are joined together using heat, pressure, and cooling. "Welding" as used herein means causing at least partial melting of the material of portions of two screen elements, joining the melted portions of the two screen elements together, and then allowing the material to cool such that the materials of the two screen elements fuse or are joined together.

[0078] When starting the welding process, the surfaces of the thermoplastic screen elements to be joined together (such as adjacent side surfaces 10222 or adjacent end surfaces 10220) are heated to their melting point or thermoplastic state. This can be a temperature of about 380°F or higher than about 380°F. Each thermoplastic material has its own melting point, which can range, for example, between 300°F and 1050°F. Then, the adjacent side surfaces (such as the side surfaces of screen element 10216a and screen element 10216b) are pressed or otherwise held together until the material cools. The pressure applied to screen elements 10216a, 10216b to push the side surfaces together allows the material to bond along seam 10310.

[0079] In some embodiments, the welding process can employ hot air plastic welding, where hot air is used to heat the thermoplastic. In some embodiments, a hot iron welding process can be used to melt the thermoplastic material along the edges of the screen elements. In this type of process, a heating element such as a heating blade, soldering iron, or some other type of heating device is brought near or into contact with the edge of the thermoplastic screen element to melt the thermoplastic material at the edge.

[0080] In some embodiments, a laser or light welding process can employ electromagnetic radiation, such as a laser, to melt the thermoplastic material at the edge. In other embodiments, friction stir welding can be used to join the thermoplastic screen elements together. In friction stir welding, heat is generated by the friction between a rotating tool and the adjacent surfaces of the thermoplastic screen elements.

[0081] In some embodiments, the welding extends from the top surface of the screen element to the bottom surface of the screen element. In some embodiments, the welding depth extends only a portion between the top and bottom surfaces. In some embodiments, the welding depth extends partially from the top surface or the bottom surface towards the opposite surface of the screen element.

[0082] In some embodiments, a computer numerical control (CNC) machine tool can automatically weld the screen elements. Multiple screen elements can be placed in a fixture or other form, and the CNC machine tool can control a heating tool, such as a laser or other light radiation tool, a heating element, a friction stir welding tool, or some other type of welding tool, to melt the edges of adjacent screen elements along the seam.

[0083] In an exemplary process, a heating element in the form of a soldering iron is heated to between 400 and 1000 °F. Adjacent edges of two screen elements are pressed together, and the heating element is moved along the joint or seam 10310, melting the thermoplastic material on the adjacent edges of the screen elements. In some cases, the heating element is close to but does not touch the seam, and then the heating tool is moved along the seam to melt and fuse the materials of the two screen elements together. In other cases, the heating element can contact the materials of the two screen elements at the seam, and then the heating element is dragged along the seam to melt and fuse the materials of the two screen elements at the seam together. In any case, the screen elements are held together when the material cools. Once cooled, the two screen elements are joined together. For example, as Figure 2 shown, the heating element can be moved or dragged along two seams 10310 while three screen elements 10216a, 10216b, 10216b are held together to connect the materials of the three screen elements along the seam 10310.

[0084] The process of forming the screen assembly can be continued by welding additional screen elements to the Figure 2 first three screen elements shown to fabricate a larger screen assembly, similar to the Figure 3 screen assembly 10400 shown. In the Figure 2 and Figure 3 embodiments shown, each screen element includes four different screening "zones" separated by reinforcement zones. Thus, the Figure 3 screen assembly 10400 shown is formed by 20 screen elements 10216 arranged in a 2×10 array. In alternative embodiments, the individual screen elements can have different sizes and different configurations. Additionally, in alternative embodiments, the number of screen elements joined together to form a screen assembly can vary according to the desired total size of the screen assembly.

[0085] In the Figure 2 and Figure 3 embodiments shown, multiple screen elements 10216 of the same size are joined together by welding or some other process to make a screen assembly. In alternative embodiments, the individual screen elements can have different sizes or shapes.

[0086] As discussed herein, a single screen element can have many different sizes, such as 1 inch × 1 inch, 1 inch × 6 inches, 1 inch × 5 inches, 2 inches × 5 inches, 4 inches × 5 inches, etc. In any case, multiple screen elements can be welded or joined together to make sub-assemblies, and multiple sub-assemblies can be joined together to make a larger screen assembly.

[0087] For example, Figure 3Shows a sub - assembly 10400 including twenty screen elements 10216. Then, multiple sub - assemblies 10400 can be joined together using the same welding or connection techniques to fabricate a screen assembly 10500 as shown in Figure 4 The advantage of fabricating the sub - assembly 10400 before fabricating a larger screen assembly is that many sub - assemblies 10400 can be fabricated in a variety of different sizes and shapes. These sub - assemblies of different sizes / shapes can be stored in a form that is easy to handle and store. Then, the sub - assemblies can be quickly assembled into a larger screen assembly according to requirements or other factors. Additionally, sub - assemblies of various sizes enable the formation of larger screen assemblies of various different sizes and shapes to meet customer needs.

[0088] Figure 4 Shows a thermoplastic screen assembly 10500 formed by joining multiple sub - assemblies 10400 together. Figure 4 The thermoplastic screen assembly 10500 shown is a 40 - inch by 30 - inch thermoplastic screen assembly, which is made by joining eight 10 - inch by 10 - inch thermoplastic sub - assemblies 10400 and four 10 - inch by 5 - inch thermoplastic sub - assemblies 10510. The thermoplastic sub - assemblies 10400, 10510 can be joined together along a seam 10310 by any of the processes referred to herein with reference to Figure 2 and 4 discussed.

[0089] After or simultaneously with forming a thermoplastic screen assembly from multiple screen elements, one or more reinforcing fibers can be embedded in the screen assembly. Figure 5A and Figure 5B Show an isometric bottom view and an isometric top view of a screen assembly 10500 in which reinforcing fibers 10610 are embedded. The reinforcing fibers 10610 are oriented within the screen assembly 10500 such that they extend in the direction in which the screen assembly will be tensioned. In the embodiments shown in Figure 5A and Figure 5B the screen assembly 10500 will be tensioned from an end 10220.

[0090] When the screen elements are joined together, the reinforcing fibers 10610 can be sandwiched between two adjacent screen elements. Alternatively or additionally, the reinforcing fibers 10610 can be embedded in the reinforcing members of the screen elements.

[0091] In Figure 1AIn the illustrated embodiment, the screen element 10216 includes three first reinforcing members 10230 that are parallel to the end 10220 and extend between the sides 10222. These first reinforcing members 10230 separate four main screening portions of the screen element 10216. Second reinforcing members 10232 of smaller width also are parallel to the end 10220 and extend between the sides 10222. These second reinforcing members 10232 extend between each row of screen apertures. The screen element 10216 also includes third reinforcing members 10234 that extend parallel to the sides 10222. Each of these third reinforcing members 10234 separates a group of respective screen apertures.

[0092] After a plurality of screen elements 10216 have been joined together to form a screen assembly 10500 similar to that shown in FIGS. 5 and 6, reinforcing fibers 10610 can be embedded in the reinforcing members 10230, 10232, 10234 of an individual screen element 10216. The reinforcing fibers 10610 can be embedded in the respective reinforcing members in a variety of ways.

[0093] In some embodiments, the reinforcing fibers 10610 can be embedded in the reinforcing members of the screen element 10216 by locally heating the reinforcing members to melt a portion of the reinforcing members. The reinforcing fibers 10610 are then pressed into the molten portion of the reinforcing members. In some embodiments, a heating element such as a soldering iron can be used to press the reinforcing fibers 10610 into the reinforcing members as the soldering iron melts the material of the reinforcing members. In some embodiments, an elongate heating element extending the full length or a portion of the length of the screen assembly 10500 can be adjacent to or in contact with a group of adjacent reinforcing members of a plurality of screen elements. The heating element then simultaneously melts the material of the plurality of reinforcing members. After the reinforcing members are melted, the reinforcing fibers are pressed into the molten material to embed the reinforcing fibers in the material of the reinforcing members. In some embodiments, the reinforcing fibers 10610 can be placed along the edge of such an elongate heating element. Then, as the heating element melts the reinforcing members, the elongate heating element can press a length of the reinforcing fibers 10610 into the reinforcing members.

[0094] Other methods can be used to melt the thermoplastic of the screen element in order to embed the reinforcing fibers 10610 in the material of the screen element. For example, a laser or light radiation can be used to cause local melting of the screen element material such that the reinforcing fibers 10610 can be embedded therein. In some embodiments, hot air also can be used to melt the material of the screen element.

[0095] In some embodiments, such as when the melting point of the reinforcing fibers is higher than the melting point of the thermoplastic material in which they are embedded, the reinforcing fibers themselves can be heated to a temperature higher than the melting point of the thermoplastic material of the reinforcing member. Then, when the heated fibers are pressed into the reinforcing member of the screen element, or possibly into a seam connecting two or more screen elements, the heat of the fibers can be used to melt the thermoplastic material.

[0096] In some embodiments, the reinforcing fibers are aramid fibers, such as Kevlar fibers. In some embodiments, metal strands are wound together with the aramid fibers to form the reinforcing fibers. In some embodiments, the reinforcing fibers are stainless steel or other metals in solid or stranded form. In some embodiments, the reinforcing fibers are metal rods. In some embodiments, the reinforcing fibers are yarns.

[0097] In some embodiments, embedding the reinforcing fibers in the thermoplastic material of the screen element can include pressing the reinforcing fibers only, for example, along the reinforcing member, into the top or bottom surface of the screen element, such that the reinforcing fibers are only partially encapsulated in the thermoplastic material of the screen element. In other embodiments, the reinforcing fibers are fully encapsulated in the thermoplastic material of the screen element.

[0098] Embedding the reinforcing fibers 10610 in the material of the reinforcing member of the screen element can prevent the reinforcing fibers 10610 from clogging any of the screen holes of the screen element. Additionally, fully embedding the reinforcing fibers 10610 in the material of the screen element or screen assembly prevents contact between the reinforcing fibers and the material being screened by the screen assembly or the parts of the screening machine on which the screen is mounted. Contact between the material to be screened or the screening machine and the reinforcing fibers 10610 tends to wear and damage the reinforcing fibers 10610, especially when the screen assembly is in a vibrating state relative to the material to be screened. Therefore, whenever possible, it is preferably to fully embed the reinforcing fibers in the material of the screen assembly.

[0099] If it is not possible to fully embed the reinforcing fibers in the material of the screen element, then it is preferable to partially embed the reinforcing fibers in the bottom surface of the screen assembly. If a portion of the reinforcing fibers is exposed on the top surface of the screen assembly, then when the screening vibrates, the reinforcing fibers will be exposed to the material being screened. The relative movement between the screen assembly and the exposed portion of the reinforcing fibers and the material being screened will wear and / or damage the reinforcing fibers. On the other hand, if the exposed portion of the reinforcing fibers is located on the bottom surface of the screen assembly, the damage to the reinforcing fibers during use is much less.

[0100] In some embodiments, the screen element can be formed to include one or more recesses configured to receive one or more reinforcing fibers. Figure 6Shown is one such screen element 10217. In this embodiment, side recesses 10240 are formed into the bottom surface of side edge 10222. In some embodiments, a central recess 10242 is formed into the bottom surface of central reinforcement member 10236, which extends centrally along the length of screen element 10217. In some embodiments, end recesses 10244 may be formed into the bottom surface of ends 10220 of screen element 10217. Of course, in any particular embodiment, only one of these types of recesses 10240 / 10242 / 10244 may be provided in the screen element.

[0101] When recesses 10240 / 10242 / 10244 are formed into the bottom surface of the screen element, these recesses help embed reinforcing fibers into the material of the screen assembly. Once a screen assembly is formed by connecting a plurality of screen elements together, the recesses of the screen elements will be aligned along the length and / or width of the screen assembly. Then reinforcing fibers can be placed into the aligned recesses and selectively heated to partially melt the material of the screen element in and around the recesses, thereby embedding the reinforcing fibers into the material.

[0102] In some cases, the reinforcing fibers will be fully embedded in the material of the screen element. In other cases, the fibers will be partially embedded in the material of the screen element, but the exposed portions of the reinforcing fibers will be located on the bottom surface of the screen assembly where damage is less likely to occur. The material to be screened will fall through the screen openings of the screen element. Since any exposed portions of the reinforcing fibers will be located on the bottom surface of the side or end of the screen element, or on the bottom surface of the reinforcing member, the exposed portions of the reinforcing fibers will be effectively isolated from the material being screened. Thus, any wear or damage to the exposed portions of the reinforcing fibers is minimized.

[0103] As described above, when screen elements are connected together to form a screen assembly or sub - assembly, reinforcing fibers 10610 may also be located between adjacent edges of the screen elements. Figure 7A Shown are two strips 10812, 10814 of screen element 10216 that are connected end - to - end along a first seam 10312. The strips 10812, 10814 of the two screen elements can be brought together by melting adjacent side edges and allowing the material of the screen element to cool to form a structure as Figure 7B shown, thereby bonding the strips 10812, 10814 of the two screen elements together. The side edges of the strips 10812, 10814 of the screen element are connected along a second seam 10314 that extends along the length of the structure.

[0104] As Figure 7AAs shown, before the two strips 10812, 10814 of the screen element are joined together, the reinforcing fibers 10610 can be positioned between the side edges of the screen element 10216 of each strip 10812, 10814 of the screen element. Once the two strips 10812, 10814 of the screen element are placed together and the material is allowed to cool, the reinforcing fibers 10610 will be embedded in the structure along the longitudinal seam 10314. Ideally, the reinforcing fibers 10610 are located between the top and bottom surfaces of the screen element 10216 such that no portion of the reinforcing fibers is exposed.

[0105] The number of reinforcing members embedded in the screen assembly can be selected to provide the screen assembly with sufficient tensile strength to withstand the tension applied to the screen assembly during the screening operation, so as to mount and fix the screen assembly on the screening machine. Since the screen assembly may be subject to large accelerations and vibration forces, the tension used to fix the screen assembly to the screening machine may be large. If the screen assembly is constructed as described above in connection with Figure 7A and Figure 7B wherein the reinforcing fibers 10610 are sandwiched between the side edges of the elongated screen element, the number of reinforcing fibers that can be embedded in the screen assembly is limited by the number of seams 10314 between adjacent strip-shaped screen elements. In some cases, this may result in the screen assembly not having a sufficient number of reinforcing fibers to properly withstand the applied tension to fix the screen assembly to the screening machine. If this is the case, it is also desirable to embed additional reinforcing fibers in the portion of the screen assembly located between the longitudinal seams 10314, where the longitudinal seams 10314 exist where the side edges of the screen element strips are joined together. Figure 8 An embodiment of the screen element 10217 that can be used for this purpose is shown.

[0106] As Figure 8 shown, the screen element 10217 includes ends 10220 and sides 10222. As Figure 1A shown in the embodiment, the screen element 10217 includes a first reinforcing member 10230 parallel to the ends 10220 and extending between the sides 10222, a second reinforcing member 10232 also parallel to the ends 10220 and extending between the sides 10222, and a third reinforcing member 10234 parallel to the sides 10222 and extending between groups of screen apertures. Figure 8The illustrated embodiment also includes a fourth reinforcing member 10236 that is parallel to the side portion 10222 and extends between the end portions 10220. The fourth reinforcing member 10236 extends downwardly in the middle of the screen element 10217 in the longitudinal direction. The fourth reinforcing member 10236 provides a location between the side edges of the screen element 10217 in which the reinforcing fibers 10610 can be embedded. In addition, as described above, recesses can be formed into the bottom surfaces of the side portion 10222, the end portions 10220, and the fourth reinforcing member 10236 to facilitate the embedding of the reinforcing fibers.

[0107] Similar to Figure 8 The plurality of screen elements 10217 shown can be end-to-end to form a long strip of screen elements 10217. The side edges of the long strip are joined together as described above, and the reinforcing fibers 10610 are also embedded between the side edges of the long strip of screen elements as described above. Once the screen assembly is formed in this way, additional reinforcing fibers 10610 can then be embedded in the fourth reinforcing member 10236 of the screen element 10217 of each elongated screen element. The recesses formed into the bottom surface of the fourth reinforcing member 10236 of the screen element can assist in embedding the additional reinforcing fibers into the screen assembly. This positions the reinforcing fibers 10610 between each longitudinal seam 10314 of the side edges of adjacent screen element strips, effectively doubling the number of reinforcing fibers within the unit width of the screen assembly.

[0108] In some embodiments, the reinforcing fibers 10610 are embedded in the reinforcing members of the screen elements. However, in some applications, it is not possible to encapsulate the entire length of the reinforcing fibers 10610 within the thermoplastic material of the screen element. Thus, some intermediate portions of the reinforcing fibers 10610 may not be encapsulated by the thermoplastic material. For example, this can occur when the reinforcing members of the screen element do not align perfectly along the entire length of the reinforcing fibers 10610.

[0109] Figure 9 is a bottom perspective view of a portion of a screen assembly 11000 having continuous reinforcing fibers embedded therein. In FIG. 5 - Figure 8 In the illustrated embodiment, the reinforcing fibers are individual reinforcing fibers that extend along the length or width of the screen assembly. Such individual reinforcing fibers are not continuous across multiple rows of screen elements. Instead, each row of screen elements receives its own single reinforcing fiber embedded therein, or the reinforcing fibers are embedded in the structure between the rows. In such an embodiment, each single reinforcing fiber has a first end that extends from a first side or a first end of the screen assembly and a second end that extends from a second side or a second end of the screen assembly.

[0110] In an alternative embodiment, only one or only a few reinforcing fibers may travel along a meandering path that crosses multiple rows of screen elements within the screen assembly or sub-assembly. In Figure 9 the illustrated embodiment, a continuous reinforcing fiber travels along a meandering path that extends between adjacent rows of screen apertures until the reinforcing fiber reaches the edge of the screen assembly. The reinforcing fiber then turns and passes through two new adjacent rows of screen apertures and then extends downwardly between the two new adjacent rows of screen apertures. This pattern repeats as the reinforcing fiber travels through the screen assembly along the meandering path.

[0111] As Figure 9 illustrated, a long straight portion 11010 of the reinforcing fiber extends between two rows of screen apertures. When the reinforcing fiber reaches the end of the screen assembly, a short transverse portion 11012 of the reinforcing fiber transversely crosses two new rows of screen apertures. A single screen assembly may include one or more continuous reinforcing fibers that extend along a path having a long direction in the direction of tension and a short direction in a direction different from the direction of tension (e.g., perpendicular to the direction of tension).

[0112] The continuous fibers that depict the meandering path may be embedded in the screen assembly as discussed above with reference to FIGS. 5-8. If recesses are formed into the bottom surface of the screen elements, the recesses may assist in embedding one or more continuous reinforcing fibers in the screen assembly in a meandering pattern. For example, referring to Figure 6 , a continuous reinforcing fiber may be placed in an aligned row of recesses 10240 that extend along the bottom surface of a side 10222 of a row of screen elements such that the reinforcing fiber extends along most of the length or width of the screen assembly. Alternatively, the reinforcing fiber may be placed in an aligned row of recesses 10242 that are formed in the bottom surface of a central reinforcing member 10236 of a row of screen elements such that the reinforcing fiber extends along most of the length or width of the screen assembly. When the reinforcing fiber approaches the edge of the screen assembly, the reinforcing fiber may pass through one or more recesses 10244 formed in the bottom surface of the end 10220 of the screen element to pass through different rows of screen elements. The reinforcing fiber may then be respectively guided back into an aligned row of recesses 10240 or 10242 on the side 10222 or the central reinforcing member 10236 of a new row of screen elements.

[0113] In some embodiments, the stiffening bars can be embedded in the screen assembly in a direction perpendicular to the direction of the reinforcing fibers. When the ends of the screen assembly are in a tensioned state, the screen assembly has a tendency to contract in a direction perpendicular to the tension direction. The stiffening bars embedded in the screen assembly and extending in a direction perpendicular to the tension direction help prevent the screen from sagging or forming a "hammocking" shape between the support members, which are located below the screen assembly when the screen assembly is installed on a screening machine. The stiffening bars can also help reduce the contraction or "hourglass" phenomenon of the screen assembly in a direction perpendicular to the tension direction. The stiffening bars can be made of any suitable material, including metals and fiberglass. In some cases, the stiffening bars can be formed of a synthetic or plastic material that has a different and harder composition than the synthetic or plastic material used to form the screen elements.

[0114] Figure 10 is an isometric view of the screen assembly 10500 with the hook strip 11100 to facilitate installation of the screen assembly on a screening machine. Figure 11 is a side view of the screen assembly 10500 with the hook strip 11100. The hook strip 11100 can be attached to the edge of the screen assembly that is tightened to secure the screen assembly 10500 to a vibratory screening machine. The hook strip 11100 can be attached to the screen assembly 10500 before, during, or after the reinforcing fibers are embedded in the screen assembly. In some embodiments, the hook strip 11100 can be attached to the screen assembly 10500 when the reinforcing fibers are embedded in the screen assembly 10500.

[0115] The hook strips 11100 can extend along opposite edges of the screen assembly and can each have a U-shaped channel that can be attached to a tensioning mechanism. The hook strips 11100 can also be formed by casting into a structural member and / or can include other structural members. The hook strips 11100 can be formed in a U-shape or any other suitable shape for attachment to a vibratory screening machine. In an exemplary embodiment, the hook strip 11100 can include a formed member, such as a metal member bent into a desired shape (e.g., U-shaped). The formed member can be connected to the body of the screen assembly 10500 by heating, pressing, mechanical fasteners, chemical bonding, molding, and / or any other suitable connection method / arrangement.

[0116] The hook strip 11100 can be formed from a variety of different materials. In some embodiments, the hook strip 11100 can be formed from a metallic material. In other embodiments, the hook strip 11100 can be formed from a synthetic or plastic material. In some embodiments, each hook strip 11100 can be an injection-molded element made of a thermoplastic. In such a case, the hook strip 11100 can be attached to the screen assembly by the melting and joining methods described above related to joining the screen elements to each other. Additionally, in the case where a portion of the hook strip 11100 is molded or formed from a synthetic material, a reinforcing member can be embedded within the hook strip 11100 to provide greater structural rigidity. The reinforcing member can be formed from any suitable material, including metal, fiberglass, or carbon fiber.

[0117] When reinforcing fibers are provided, the ends of the reinforcing fibers passing through the screen assembly are attached to the hook strip 11100. Attaching the reinforcing fibers to the hook strip 11100 allows the tension applied by the hook strip 11100 to be borne in part by the reinforcing fibers. This can be accomplished in a variety of different ways.

[0118] In some embodiments, the ends of the reinforcing fibers are attached to the hook strip 11100 by an adhesive and / or mechanical attachment means. If the hook strip 11100 is formed from a molded synthetic material, the reinforcing fibers can be embedded into the material of the hook strip 11100 in a manner very similar to the way the reinforcing fibers are embedded into the material of the screen elements making up the screen assembly. In fact, one or more recesses can be molded into the material of the hook strip 11100 to facilitate embedding the reinforcing fibers into the material of the hook strip 11100.

[0119] If the screen assembly includes one or more reinforcing fibers embedded in a serpentine manner in the screen assembly, then the hook strip 11100 is connected to the screen elements forming the edge of the screen assembly such that the tension applied by the hook strip 11100 can be borne by the embedded reinforcing fibers.

[0120] Figure 12A and Figure 12B An embodiment is shown where a thin metal member 11300 is bent to at least cover the interior of the U-shaped hook strip 11100. The metal member 11300 can extend around the exterior and top of the hook strip 11100, around the back of the hook strip 11100, and down to the bottom of the hook strip 11100. In some embodiments, such a metal member 11300 is formed in a hook shape and curled or otherwise attached to the screen assembly to form the hook strip 11100.

[0121] In use, the screen assembly 10500 is installed on a vibrating screen machine in a known manner. More specifically, the screen assembly 10500 is installed on the screen deck of the vibrating screen machine. The grooved drawbar of the tensioning mechanism of the vibrating screen machine is received within the hook strip 11100, and the drawbar tensions the screen assembly to secure the screen assembly 10500 to the screen of the vibrating screen machine. When the screen deck and the attached screen assembly 10500 vibrate during the screening operation, the tension applied by the drawbar is also used to keep the screen assembly 10500 stationary relative to the screen deck.

[0122] Figure 13 A top perspective view of a screen assembly 11400 having an end boundary 11410 is shown. Figure 14 is Figure 13 A bottom perspective view of a corner of the screen assembly 11410 shown. The screen assembly 11400 is configured to be tensioned from side to side using hooks 11420 located on the sides of the screen assembly 11400. The hooks 11420 extend above the top surface of the screen assembly 11400. The end boundary 11410 may be made of the same thermoplastic material as the screen element. In some embodiments, the end boundary 11410 is made of a material different from the screen element. In some embodiments, the end boundary 11410 is made of a TPU material. The end boundary 11410 may be added to the screen assembly before, after, or at the same time as the hook strip 11420 is added to the screen assembly.

[0123] Figure 14 A view shows multiple reinforcing fibers 10610 embedded in the material of the screen assembly 11400. In this embodiment, the ends of the reinforcing fibers 10610 are also embedded in the hooks 11420 present on the sides of the screen assembly 11400. As a result, the tension applied by the tensioning installation mechanism to the hooks 11420 is directly transferred to and borne by the reinforcing fibers 10610. Of course, in alternative embodiments, the reinforcing fibers 10610 may be attached to the hooks 11420 by other attachment means discussed more fully above.

[0124] When installed on the screening machine, the end boundary 11410 provides an interface between adjacent screens. The end boundary 11410 may increase the length of the screen assembly 11400 such that the size of one or more completed screen assemblies is adapted to the size of the screening machine using the screen assembly. The end boundary 11410 may also provide protection for the edges of the outermost screen elements. Although the screen elements are robust for screening materials, their edges may be damaged by impact. The end boundary 11410 protects the edges from such impact and other damage.

[0125] Figure 15 A top perspective view of a screen assembly 11600 having a side boundary 11610 is shown. Figure 16 isFigure 15 Bottom perspective view of the angle of the screen assembly 11600 shown. The screen assembly 11600 is configured to utilize hooks 11620 located at the ends of the screen assembly 11600 for end-to-end tensioning. The hooks 11620 extend below the bottom surface of the screen assembly 11600. The side boundaries 11610 can be made of the same thermoplastic material as Figure 13 and Figure 14 the end boundaries 11410 of the embodiment shown. The side boundaries 11610 can be added to the screen assembly 11600 before, after, or at the time the hook strips 11620 are added to the screen assembly 11600. Like the end boundaries 11410 of the previous embodiments, the side boundaries 11610 of this embodiment can provide protection for the edges of the outermost screen elements. Although the screen elements are sturdy for screening materials, their edges can be damaged by impact. The side boundaries 11610 protect the edges from such impact and other damage.

[0126] Figure 17A Two screen elements 10416 are shown, which are injection molded to include end protrusions 10420 and end recesses 10422. The screen elements also include side protrusions 10430 and side recesses 10432. The protrusions and recesses are designed such that when the side edges or end edges of two screen elements 10416 contact each other before being welded or joined together, the protrusions are received in the recesses. As a result, the two screen elements are well aligned with each other. In other words, the protrusions and edges can help ensure that the screen elements are properly aligned with each other before being joined together.

[0127] Figure 17B Another embodiment is shown where the protrusions 10420, 10430 are wider at the ends than at the bottom. The recesses 10422, 10432 have corresponding shapes. When two such screen elements are placed together, the protrusions 10420, 10430 will be pressed down into the recesses 10422, 10432, and the shapes of the protrusions and recesses will hold the two screen elements together. The shaped protrusions 10420, 10430 and recesses 10422, 10432 will help hold the screen elements together during the process of joining multiple screen elements.

[0128] Figure 18 Steps of a first method 1800 for forming a screen assembly are shown. The method begins and proceeds to step 1802, in which multiple screen elements are provided or formed. Forming the screen elements can include injection molding plastic or synthetic material to form the screen elements. The screen elements can have the above-described features, especially can have the features of the screen elements Figure 1A - Figure 2 described.

[0129] Next, in step 1804, the side edges of the screen elements are interconnected to form a screen assembly. The side edges can be connected by a variety of different methods, including fusing the materials of the side edges together, bonding or gluing, using fasteners, and other similar methods. In some embodiments, connecting the side edges of plastic or synthetic screen elements can include heating the edges to be connected so that the material at the side edges is at least partially melted, pressing the side edges together, and allowing the material to cool so that the materials along the side edges fuse together. As described above, the material of the side edges can be at least partially melted. Of course, the side edges can also be connected in various other ways.

[0130] In some cases, the method will end after step 1804. In other words, once a sufficient number of screen elements are attached to each other to form a screen assembly of the desired size, the method can end and the screen elements can be used.

[0131] In an alternative embodiment, an additional step 1806 is formed to embed one or more reinforcing fibers into the material of one or more screen elements. As described above, the reinforcing fibers can be arranged such that they extend in the direction in which the screen assembly will be tensioned in order to secure the screen assembly to the screening machine. As described above, the reinforcing fibers can be embedded in the material of the screen elements in various ways. This can include heating the material of a selected portion of a selected screen element such that the material is at least partially melted and pressing the reinforcing fibers into the melted material.

[0132] In some embodiments, multiple reinforcing fibers are embedded in the material of the screen elements of the screen assembly. In other embodiments, one or only a few reinforcing fibers are embedded in the material of the screen elements of the screen assembly in a meandering manner such that one or a few reinforcing fibers extend through multiple portions of the screen assembly.

[0133] In some embodiments, one or more reinforcing fibers are embedded in the material of the screen assembly along seams formed between the side edges of the screen elements that make up the screen assembly. This can be accomplished as described in more detail below in connection with Figure 8 more detailed description.

[0134] In some embodiments, the method will end after step 1806. In other cases, an optional additional step 1808 is performed, in which side bars, end bars, pressure bars, or hook strips are attached along one or more edges of the screen assembly. Side bars or end bars can be provided to protect the side edges of the screen elements that would otherwise be exposed on an outer edge of the screen assembly. Pressure bars can be mounted to the edges of the screen assembly to facilitate pressing the screen assembly onto the screening machine. Similarly, hook strips can be connected to opposite side edges or opposite end edges of the screen assembly such that the screen assembly can be mounted to the screening machine by a tension mounting system.

[0135] The side bars, end bars, compression bars, and / or hook strip bands can be connected to the screen elements of the screen assembly in various ways. The connection can be achieved by crimping, mechanical fasteners, chemical or adhesive bonding, or by fusing the material of the screen elements to the material of the side bars, end bars, compression bars, and hook strip bands.

[0136] Figure 19 Steps of another method 1900 for forming a screen assembly are shown. In this method, reinforcing fibers are embedded in the structure when the side edges of the screen elements are joined together. Method 1900 begins and proceeds to step 1902, in which a plurality of screen elements are provided or formed. Here again, forming the screen elements can include injection molding plastic or synthetic material to form the screen elements. The screen elements can have the above-described features, particularly having the features of the screen elements described Figure 1A - Figure 2 herein.

[0137] In step 1904, a subset of the screen elements are attached to each other to form a strip of joined screen elements. This can include end-to-end connection of elongate screen elements to form a strip of joined screen elements. The screen elements can be connected to each other in any of the ways described previously.

[0138] In step 1906, one or more reinforcing fibers are positioned between the side edges of two strips of joined screen elements. In step 1908, the side edges of two adjacent strips of joined screen elements are attached to each other, sandwiching one or more reinforcing fibers between the strips of joined screen elements. This can be achieved by heating the material of the screen elements along the side edges until the material begins to melt or changes from solid to liquid. Then, the side edges of the adjacent strips of joined screen elements are pressed together, with one or more reinforcing fibers sandwiched between the side edges. Then the material of the screen elements along the side edges is allowed to cool. As a result, the material of the side edges of the screen elements is fused together to join the strips of joined screen elements. In addition, one or more reinforcing fibers are ultimately embedded in the material of the screen elements along the joint or seam formed between the side edges of the strips of joined screen elements. Of course, the strips of joined screen elements can be attached to each other in various other ways (e.g., with an adhesive or with mechanical fasteners).

[0139] The above process can be repeated multiple times to add additional strips of joined screen elements to the first two strips of joined screen elements, with one or more reinforcing fibers being embedded between the existing structure and the new strip of joined screen elements each time a new strip is added. This process allows for the construction of large screen assemblies one strip at a time. In some embodiments, once a sufficient number of strips of joined screen elements have been attached to each other, the method ends. In other embodiments, optional additional steps can be performed.

[0140] In a first optional step 1910, after all the connected strips of screen elements have been attached to each other, additional reinforcing fibers can be added to the screen assembly. This can be achieved by heating selected portions of the screen elements to cause these portions to at least partially melt. One or more reinforcing fibers are then pushed into the heated portions of the screen elements, and the heated portions are allowed to cool and harden. In a preferred method, the reinforcing fibers are inserted deep enough into the heated portions of the screen elements such that once the material has cooled and hardened, the reinforcing fibers will be completely encapsulated within the material of the screen elements. This optional step 1910 can be performed to add additional reinforcing fibers to the screen assembly at locations between joints or seams where the strips of screen elements are joined (where other reinforcing fibers are provided).

[0141] In another optional step 1912, side bars, end bars, pressure bars, or hook strips are attached along one or more edges of the screen assembly. Side bars or end bars can be provided to protect the edges of the screen elements that would otherwise be exposed on an outer edge of the screen assembly. Pressure bars can be mounted to the edges of the screen assembly to facilitate pressing the screen assembly onto a screening machine. Similarly, hook strips can be attached to opposite side edges or opposite end edges of the screen assembly such that the screen assembly can be installed onto a screening machine by a tension mounting system.

[0142] Here again, step 1912 can include attaching the side bars, end bars, pressure bars, and / or hook strips to the screen elements of the screen assembly in various ways. The connection can be achieved by crimping, mechanical fasteners, chemical or adhesive bonding, or by fusing the material of the screen elements to the material of the side bars, end bars, pressure bars, and hook strips.

[0143] When the screen assembly is made as described above, where the side edges of the screen elements are adhesively bonded or fused together, damaged portions of the screen assembly can be repaired. For example, if a portion of the screen assembly is damaged during use, the damaged portion can be cut out and replaced with a new portion of the appropriate dimensions of a new screen element. This may include cutting out a strip of screen elements end-to-end and extending from one side of the screen assembly to the other, where the removed strip includes the damaged portion. Then, a new strip of screen elements of similar dimensions, also end-to-end, can be attached to the edges of the remaining portion of the screen assembly in substantially the same manner as the screen assembly was initially manufactured. The result is a repaired screen assembly that includes a new strip of screen elements. Such repair is not possible on thermoset screens because once the thermoset material has cured, the edges cannot be joined to a new repair patch by melting and fusing.

[0144] Ideally, the new strip of screen elements inserted into the screen assembly to replace the damaged portion will include corresponding reinforcing fibers. If this is the case, the reinforcing fibers can be attached to the hook ends of the screen assembly that are used to install the screen assembly onto a screening machine.

[0145] In some cases, when replacing the screen element strip, it may not be possible to include reinforcing fibers in the new strip inserted into the screen assembly to replace the damaged part. Similarly, it may not be possible to connect the ends of one or more reinforcing fibers in the new part to the hook-shaped ends used to mount the screen assembly to the screening machine. This is acceptable because the remaining reinforcing fibers can provide sufficient strength to the screen assembly.

[0146] In other cases, the reinforcing fibers associated with the newly inserted repair strip can be attached to the hook ends. This can be achieved by heating and melting operations, by adhesives, or by mechanical connection mechanisms.

[0147] When the screen assembly is attached to the screening machine and used for screening materials, it is ideally desired that the material to be screened be exposed to the portion of the screen element including the screen holes as much as possible. When the material to be screened simply rests on or vibrates on the sides, ends, and reinforcing members of the screen element, no screening activity occurs. One way to help keep the material to be screened in contact with the portion of the screen element having the screen holes is to form the screen assembly such that the portion of the screen assembly that does not include the screen holes is raised relative to the portion of the screen assembly that includes the screen holes.

[0148] Figure 2 Three screen elements 10216a, 10216b, and 10216c are shown, which are connected at seams 10310 along their edges. As described above, during the connection process, the side edges of the screen are heated and pressed together. This causes the materials at the edges to fuse together to connect the screen elements to each other.

[0149] Figure 20A is Figure 2 A side view of the shown assembly. The side edge of the first screen element 10216a is connected to the side edge of the second screen element 10216b along the seam 10310. However, in this embodiment, once the side edges of the screen are heated to the melting point, the force pushing the side edges together is large enough such that some of the material of the side edges is pushed upward at the seam 10310. Once the materials of the screen elements 10216a, 10216b cool, the result is that the top protruding portion 10312 extends upward along the seam 10310 connecting the side edges. This configuration occurs when the two screen elements 10216a, 10216b are joined together at the edges and rest on a flat surface such that the material of the edges can only protrude upward in response to the force pushing the screen elements together.

[0150] If the entire screen assembly is formed with a top protrusion 10312 along the joint 10310 that joins the strips of the screen elements together, there will be a raised portion between the parts of the screen elements that include the screen apertures. This will tend to keep the material to be screened in the portion between the top protrusions 10312 where the screening openings are located, thus assisting the screening process.

[0151] Figure 20B Another embodiment is shown where a bottom protrusion 10314 is also formed along the bottom surface of the seam 10310. Such a configuration can be advantageous because once the screen assembly is installed on the screen plate of a screening machine, the bottom protrusion 10314 can cause the joint 10310 between the screen elements to be pushed upwards, further lifting the top protrusion 10312 above the portions of the screen elements that include the screen apertures.

[0152] The top protrusion 10312 and the bottom protrusion 10314 can also be formed in alternative ways. For example, once a set of screen elements are joined together by one of the above processes, the top protrusion 10312 and / or the bottom protrusion 10314 can be separate elements added along the joint 10310 between the screen elements. The material of the separate elements forming the top protrusion 10312 and / or the bottom protrusion 10314 can be made of the same material as the screen elements, in which case the separate elements can be joined to the screen elements along the joint 10310 using a method similar to that used above for joining the screen elements together. Alternatively, the separate elements forming the top protrusion 10312 and / or the bottom protrusion 10314 can be joined to the screen elements along the joint 10310 by alternative means, such as by an adhesive. Additionally, the separate elements forming the top protrusion 10312 and / or the bottom protrusion 10314 can be formed from a different type of material than that used to form the screen elements.

[0153] The foregoing embodiments have mainly considered screen assemblies that are installed on a screening machine by a tensioning mounting mechanism. An alternative way to install the screen assembly on a screening machine is by a compression mounting mechanism. As long as the screen assembly includes a support plate, the screen assembly manufactured as described above can be used on a screening machine that includes a compression mounting mechanism.

[0154] Figure 21 A support plate 300 is shown that can be incorporated into a screen assembly that can be installed on a screening machine by a compression mounting mechanism. The support plate includes a front edge 344, a rear edge 346, a first side edge 340, and a second side edge 342. A plurality of holes 348 are formed in most of the surface of the support plate 300. When a layer of screen elements having screen apertures is installed on top of the support plate 300, the particles of the material to be screened passing through the screen apertures of the screen elements can pass through the support plate 300 through the holes 348.

[0155] The support plate includes a plurality of first mounting holes 350a positioned along the first side edge 340 and a plurality of second mounting holes 350b positioned along the second side edge 342. Each mounting hole 350a, 350b may include an alignment notch 354. The mounting holes 350a, 350b interact with elements of a compression mounting system to connect a screen assembly including the support plate 300 to a screening machine.

[0156] The support plate 300 may be made of a metal material or a composite material. If the support plate 300 is formed of a composite material, a reinforcement member may be incorporated into the support plate or attached to the support plate to increase the rigidity of the support plate.

[0157] Figure 22 Shown include Figure 21 300 is shown in cross-sectional view of a portion of screen assembly 20000 of support plate 300. Screen assembly 20000 includes a screening layer 20100 formed by a plurality of screen elements 10216a, 10216b, and 10216c, which are connected along their side edges at seams 10310 as described above. Any of the aforementioned embodiments in which a plurality of screen elements are connected together along their side edges and / or end edges can form screening layer 20100.

[0158] Screening layer 20100 can be attached to support plate 300 in a variety of different ways. In some embodiments, the screen elements of screening layer 20100 can be connected to the top surface of support plate 300 using adhesives, mechanical fasteners, clamps, or other devices. In other embodiments, the material of the screen elements of screening layer 20100 can be melted and fused to the material of support plate 300. This may be advantageous when the support plate is made of a synthetic material.

[0159] Figure 23 310. The screen layer 23100 is made of a plurality of screen elements 10216a, 10216b, 10216c, 10216d connected along their side edges at seams 10310. In this embodiment, the support plate 310 includes an undulating structure. The screen layer 23100 is sufficiently flexible so that it can be bonded to the top surface of the support plate 310 so that the screen layer conforms to the contour of the support plate 310. By forming a Figure 23 The screen assembly shown can increase the total screening area per unit width of the screen assembly.

[0160] although Figure 23The illustrated embodiments include undulating structures with tips, but other shapes are possible. For example, the support plate 310 and the screen layer 23100 can have smooth, rounded undulating structures. Also, the flat portions 23102 between the undulating structures can be eliminated so that the entire screen assembly is a series of undulating structures. Additionally, the undulating structures can extend upward and downward from a central plane. Any combination of shapes is possible.

[0161] Figure 24A The end edges of two screen elements 24102 and 24110 are shown. The screen elements have angled side edges. The angled side edges allow the screen elements 24102 and 24110 to be joined together to form a screen assembly with sharp protrusions or undulating structures.

[0162] The first screen element 24102 has a first side edge 24104 and a second side edge 24106 that slope outward and downward from the top surface such that the bottom surface has a greater width than the top surface. As described below, the first type of screen element 24102 will ultimately form the flat portions of the screen assembly.

[0163] The second screen element 24110 also has angled side edges 24112, 24114. As described below, the second screen element 24110 will form the upward or downward protruding portions of the screen assembly. The angles formed between the side edges 24112, 24114 and the top and bottom surfaces of the screen element 24110 will depend on the desired shape of the screen assembly formed by this type of screen element 24110.

[0164] Figure 24B is a side view of a screen assembly 24100 formed by a plurality of screen elements 24102, 24110 as Figure 24A shown. As Figure 24B shown, the opposing side edges 24104, 24106 of each first type screen element 24102 form the flat portions of the screen assembly 24100 between the protruding portions. Two second type screen elements 24110 form each protruding portion between the flat portions of the screen assembly 24100 formed by the first type screen elements 24102. The first side edge 24112 of each second type screen element 24110 is connected to the side edge of the first type screen element 24102. The second side edges 24114 of each second type screen element 24110 are joined together to form the peak structure 24120 of each protrusion of the screen assembly 24100.

[0165] From Figure 24B the description, it can be seen that the angles of the side edges of the first type and second type screen elements 24102, 24110 can vary such that the protrusions project upward from the flat portions at different angles and heights.

[0166] The connection of the side edges of the screen elements forming the screen assembly 24100 as shown in Figure 24B can be accomplished by a method similar to that discussed above. In some cases, it may be helpful to place the screen elements on top of a formed assembly fixture that has a shape similar to the desired final form of the screen assembly. Once the screen elements are placed on the formed assembly fixture such that they form the shape as shown in Figure 24B , the side edges can be joined together by the heating and fusing process described above. The joining process can include inserting one or more reinforcing fibers between the side edges of the screen elements. Of course, the side edges can also be joined by alternative means, such as with adhesives or mechanical fasteners.

[0167] Figure 25 Another embodiment of the screen assembly is shown, which includes a flat support plate 300 similar to that shown in Figure 21 . However, in this embodiment, the screen layer 24100 is formed to have a corrugated structure as shown in Figure 24B . This means that the inclined side edges of the screen elements are joined together such that the final screen assembly has ridges or protrusions.

[0168] In an alternative embodiment, the flat layers of the screen elements can be joined together as described above. Once the side edges of the screen elements are joined together, the joined screen element layers can be inserted into a forming die having the desired corrugated structure, and the material of the screen elements can be heated to near the melting point. By heating the material of the screen elements and applying pressure to the assembly with the forming die, the screen assembly can be made to assume a corrugated shape similar to that shown in FIG. 24.

[0169] A damaged screen assembly manufactured as described above can also be repaired by covering the damaged portion. For example, a flat sheet of thermoplastic material without holes can be adhered or fused to the appropriate location on the damaged portion of the screen assembly. Alternatively, the patch can include screen holes. In either case, since the material of the existing screen elements of the screen assembly can be remelted after the screen assembly is formed, the damaged portion of the screen assembly can be repaired by heating the patch and fusing it to the appropriate location on the damaged portion. Of course, adhesives can also be used to bond the patch to the appropriate location on the damaged portion.

[0170] Prior methods of joining injection molded screen elements together to form a screen assembly relied on the use of subgrids that could be joined together to form the screen assembly. See, for example, U.S. Patents 10,046,363; 9,409,209; 10,576,502 and 11,161,150, the contents of all of which are incorporated herein by reference. The screen assemblies disclosed in the cited patents include injection molded screen elements mounted on subgrids. The subgrids are then interconnected with integral fasteners to form the screen assembly.

[0171] In the devices and methods described above, the side edges of the injection molded screen elements are fastened together by adhesion, fusion, or other joining methods such that the formation of the screen assembly does not require a subgrid. Fabricating a screen assembly by bonding the side edges of the screen elements together without using a subgrid has a number of advantages.

[0172] First, there is no need to fabricate a subgrid, which represents a significant savings in time and cost. Second, there is no need to spend time and effort attaching the screen elements to the subgrid prior to creating the screen assembly. Instead, once the screen elements have been formed, they can be immediately attached to each other by the methods described above to form the screen assembly.

[0173] In addition, by eliminating the subgrid, the resulting screen assembly is thinner, lighter, and more flexible. This makes transportation and shipping easier and less expensive. In some cases, it may also make it easier to install the screen assembly onto a screening machine.

[0174] Furthermore, in the joining method described above, where the side edges of the injection molded screen elements are fused together, a screen assembly can be produced that has a greater tensile strength than a screen assembly held together by fasteners of a subgrid. As noted above, the ability to add reinforcing fibers to the screen assembly can increase the tensile strength. Adding reinforcing fibers to a screen assembly formed using a subgrid is not possible, or at least very difficult.

[0175] One disadvantage of a screen assembly formed using a subgrid is that the integral fasteners used to join the subgrids together do not ensure that the resulting assembly has no gaps between the individual elements. The side edges of the screen elements mounted on top of the subgrid are not bonded together. As a result, the material being screened may fall between the side edges of the screen elements. Similarly, the subgrids themselves are joined together using integral clamping fasteners, but the side edges between the subgrids are not sealed. As a result, any material that falls between the side edges of two adjacent screen elements will also fall between the side edges of the subgrids on which the screen elements are mounted. All of these factors can lead to the problem of material bypassing the screen elements and falling between the individual elements that make up the screen assembly formed by the subgrid.

[0176] The problem of material bypassing the screen element is particularly severe when the screen element is configured to have very small aperture sizes to allow only very small particles to pass through during screening. Unfortunately, the gaps between adjacent screen elements and between adjacent sub-grids can be of a size similar to or larger than the apertures in the screen element. This will allow particles larger than the apertures to bypass the screen element, which is problematic.

[0177] Since the side edges of the screen elements are bonded or fused together, all of the above problems of particle bypassing the screen element are solved by the screen assembly formed as described above. There are no gaps between the screen elements. And since there are no sub-grids, there are no corresponding gaps between the sides of the sub-grids.

[0178] In addition, it seems that in some cases the presence of sub-grids can impede screening performance. When subjected to vibration, the sub-grids impede the movement of the screening surface. When the screen elements are not connected to the underlying sub-grids, they can move more freely and, due to the lack of mass associated with the sub-grids, they can move faster. The screen elements without sub-grids can also move a greater distance in each direction under vibration than the screen elements connected to the sub-grids might move. All of these factors result in a screen assembly formed only of screen elements having better overall screening performance than screen elements connected to sub-grids.

[0179] A screen assembly formed from a plurality of injection-molded screen elements as described above has many advantages compared to a screen assembly formed by casting a thermosetting material. As described above, curing the screen assembly by casting a thermosetting material takes longer than injection-molding a plurality of screen elements and attaching them together to form a screen assembly, as described above. The casting of the thermosetting material takes several hours, sometimes up to 10 hours, to form a single large screen assembly. In contrast, a single screen element can be injection-molded in a few seconds, and the time required to injection-mold a sufficient number of screen elements to fabricate a large screen is still less than an hour. The additional time required to connect the injection-molded screen elements to form a screen assembly is still far less than the time required to wait for the thermosetting material to cure.

[0180] In addition, the size of the screen assembly formed by curing a thermosetting material in a mold is limited by the size of the mold. In contrast, one can fabricate a screen assembly of virtually any size from a plurality of injection-molded screen elements. There are no size limitations on the mold.

[0181] There are also advantages in terms of waste or scrap. If a single small part of a screen assembly made by casting a thermosetting material is deformed, or when removed from the mold, a single small part of the screen assembly formed by casting a thermosetting material is damaged, then the entire screen assembly is scrapped. And the time required to manufacture the screen assembly is lost. In contrast, if a single small injection-molded screen element is deformed, only the small screen element is scrapped. And because it is made of thermoplastic, it can be remelted and reused to form a new screen element. The only time lost is the very short time spent manufacturing the defective injection-molded screen element. Due to these factors, compared with screen assemblies cast from thermosetting materials, injection-molded screen elements waste much less time and scrap when problems occur.

[0182] The disclosed embodiments can be configured for a variety of different vibrating screening machines. This includes machines designed for wet screening and dry screening applications, machines with multiple layers of platforms and / or multiple screening baskets, and machines with various screen attachment means, such as tensioning mechanisms (top-mounted and bottom-mounted), compression mechanisms, clamping mechanisms, magnetic mechanisms, etc. For example, the screen assembly described in the present application can be configured to be mounted on the vibrating screening machines described in U.S. Pat. Nos. 7,578,394; 5,332,101; 6,669,027; 6,431,366 and 6,820,748.

[0183] In fact, the screen assemblies described herein may include sides, binding bars, and hook strips that include U-shaped members configured to receive top-mounted tensioning members, such as those described in U.S. Pat. No. 5,332,101; sides, adhesive bars that include finger-receiving holes configured to receive bottom-mounted tensioning, such as those described in U.S. Pat. No. 6,669,027; side members or binding bars for compressive loads, such as those described in U.S. Pat. No. 7,578,394; or can be configured for connection and loading on multi-layer machines, such as the machines described in U.S. Pat. No. 6,431,366. The screen assemblies and / or screen elements can also be configured to include the features described in U.S. Pat. No. 8,443,984, including the guide assembly technology and the prefabricated panel technology described therein.

[0184] Further, the screen assembly and screen elements can be configured to be incorporated into U.S. Patents 8,439,203; 7,578,394; 5,332,101; 4,882,054; 4,857,176; 6,669,027; 7,228,971; 6,431,366; and 6,820,748; 8,443,984; and 8,439,203; these patents and their related patent families and applications, as well as the patents and patent applications cited in these documents, are hereby expressly incorporated by reference. Above, exemplary embodiments have been described. However, it will be apparent that various modifications and variations can be made without departing from the broad spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive.

Claims

1. A method of forming a screen assembly, comprising: forming a plurality of screen elements from a synthetic material or a plastic material, each screen element having a screening surface with a plurality of screening apertures separated by screening surface elements; attaching the plurality of screen elements to one another to form a screen assembly, the screen assembly including a continuous screening surface formed by the screening surfaces of the plurality of screen elements, wherein the plurality of screen elements are attached to one another by directly securing adjacent side edges of the screen elements to one another.

2. The method according to claim 1, wherein, Directly securing adjacent side edges of the screen elements to one another includes fusing the materials at the adjacent side edges of the screen elements together.

3. The method according to claim 2, further comprising providing reinforcing fibers, wherein directly securing adjacent side edges of the screen elements to one another includes directly securing adjacent side edges of selected ones of the plurality of screen elements to one another such that the reinforcing fibers are trapped between the adjacent side edges of the selected ones of the screen elements and such that the reinforcing fibers are embedded in the material of at least some of the screen elements.

4. The method according to claim 1, wherein Directly securing adjacent side edges of the screen elements to one another includes directly securing the adjacent side edges of the screen elements to one another with an adhesive.

5. The method according to claim 4, further comprising providing reinforcing fibers, wherein directly securing the adjacent side edges of the screen elements to one another with an adhesive includes positioning the reinforcing fibers between the adjacent side edges of selected ones of the screen elements before directly securing the adjacent side edges of the selected ones of the screen elements to one another with the adhesive such that once the adjacent side edges of the selected ones of the screen elements are directly secured to one another, the reinforcing fibers are trapped between the adjacent side edges of the selected ones of the screen elements.

6. The method according to claim 1, further comprising: providing a plurality of reinforcing fibers; and embedding the plurality of reinforcing fibers in the material of at least some of the screen elements.

7. The method according to claim 1, wherein forming the plurality of screen elements includes forming each screen element by: each screening aperture between adjacent screening surface elements having a width between about 10 μm and about 6000 μm; each screening surface element between adjacent screening apertures having a thickness between about 10 μm and about 4000 μm; and the open screening area of the screen element being between about 15% and about 40% of the total area of the screen element.

8. The method according to claim 1, wherein forming the plurality of screen elements includes forming each screen element by: each screening aperture between adjacent screening surface elements having a width between about 10 μm and about 300 μm; each screening surface element between adjacent screening apertures having a thickness between about 60 μm and about 500 μm; and the open screening area of the screen element being between about 15% and about 40% of the total area of the screen element.

9. A method of forming a screen assembly, comprising: providing a plurality of screen elements formed from a synthetic material or a plastic material, each screen element having a screening surface with a plurality of screening apertures separated by screening surface elements; Adjacent side edges of a plurality of screen elements are directly coupled to each other to form a screen assembly, the screen assembly including a continuous screening surface composed of screening surfaces of the plurality of screen elements; And At least one reinforcing fiber is attached to at least some of the screen elements.

10. The method according to claim 9, wherein, Directly coupling the adjacent side edges of the screen elements to each other includes fusing the materials at the adjacent side edges of the screen elements together.

11. The method according to claim 10, wherein attaching at least one reinforcing fiber to at least some of the screen elements includes embedding at least one reinforcing fiber in the material of at least some of the plurality of screen elements.

12. The method according to claim 9, wherein, Directly coupling the adjacent side edges of the screen elements to each other includes directly coupling the adjacent side edges of the screen elements to each other with an adhesive.

13. The method according to claim 12, wherein attaching at least one reinforcing fiber to at least some of the screen elements includes attaching at least one reinforcing fiber to at least some of the screen elements with an adhesive.

14. The method according to claim 9, wherein forming the plurality of screen elements includes forming each screen element by: The width of each screen hole between adjacent screening surface elements is between about 10 μm and about 300 μm; The thickness of each screening surface element between adjacent screen holes is between about 60 μm and about 500 μm; and The open screening area of the screen element is between about 15% and about 40% of the total area of the screen element.

15. A screen assembly for use on a screening machine, comprising: A plurality of screen elements made of a synthetic material or a plastic material, each screen element having a screening surface with a plurality of screen holes separated by screening surface elements, wherein adjacent side edges of the plurality of screen elements are directly fixed to each other to form a screen assembly having a continuous screening surface composed of screening surfaces of the plurality of screen elements; and At least one reinforcing fiber fixed to selected ones of the plurality of screen elements.

16. The screen assembly according to claim 15, wherein, The adjacent side edges of the plurality of screen elements are directly fixed to each other by fusing the materials of the adjacent side edges of the screen elements.

17. The screen assembly according to claim 16, wherein, At least one reinforcing fiber is embedded in the material of selected ones of the plurality of screen elements such that at least one reinforcing fiber is positioned between the top and bottom surfaces of the selected ones of the screen elements.

18. The screen assembly according to claim 15, wherein, The adjacent side edges of the plurality of screen elements are fixed to each other by an adhesive.

19. The screen assembly according to claim 18, wherein, At least one reinforcing fiber is fixed to selected ones of the plurality of screen elements by an adhesive.

20. The screen assembly according to claim 15, wherein, Each of the plurality of screen elements includes a reinforcing member without screen holes, and wherein the at least one reinforcing fiber is fixed to the reinforcing members of at least some of the plurality of screen elements.

21. The screen assembly according to claim 15, wherein, For each of the plurality of screen elements: The width of each screen hole between adjacent screening surface elements is between about 10 μm and about 6000 μm; The thickness of each screening surface element between adjacent screen holes is between about 10 μm and about 4000 μm; and The open screening area of the screen element is between approximately 15% and approximately 40% of the total area of the screen element.

22. The screen assembly according to claim 15, wherein, For each of the plurality of screen elements: The width of each screen aperture between adjacent screening surface elements is between approximately 10 μm and approximately 300 μm; The thickness of each screening surface element between adjacent screen apertures is between approximately 60 μm and approximately 500 μm; and The open screening area of the screen element is between approximately 15% and approximately 40% of the total area of the screen element.

23. The screen assembly according to claim 15, wherein, For each of the plurality of screen elements: The width of each screen aperture between adjacent screening surface elements is between approximately 10 μm and approximately 125 μm; The thickness of each screening surface element between adjacent screen apertures is between approximately 60 μm and approximately 127 μm; and The open screening area of the screen element is between approximately 15% and approximately 40% of the total area of the screen element.

24. A screen assembly for use on a screening machine, comprising a plurality of injection molded screen elements made of synthetic material or plastic material, each screen element having a screening surface with a plurality of screen apertures separated by screening surface elements, wherein adjacent side edges of the plurality of screen elements are directly coupled to each other to form the screen assembly, and the screen assembly has a continuous screening surface formed by the screening surfaces of the plurality of screen elements.

25. The screen assembly according to claim 24, wherein, The adjacent side edges of the screen elements are coupled to each other by fusing the materials of the adjacent side edges of the screen elements together.

26. The screen assembly according to claim 24, wherein, The adjacent side edges of the screen elements are coupled to each other by an adhesive.

27. The screen assembly according to claim 24, wherein, For each of the plurality of screen elements: The width of each screen aperture between adjacent screening surface elements is between approximately 10 μm and approximately 6000 μm; The thickness of each screening surface element between adjacent screen apertures is between approximately 10 μm and approximately 4000 μm; and The open screening area of the screen element is between approximately 15% and approximately 40% of the total area of the screen element.

28. The screen assembly according to claim 24, wherein, For each of the plurality of screen elements: The width of each screen aperture between adjacent screening surface elements is between approximately 10 μm and approximately 300 μm; The thickness of each screening surface element between adjacent screen apertures is between approximately 60 μm and approximately 500 μm; and The open screening area of the screen element is between approximately 15% and approximately 40% of the total area of the screen element.

29. The screen assembly according to claim 24, further comprising a reinforcing member attached to at least one of the plurality of screen elements.

30. The screen assembly according to claim 29, wherein, The reinforcing member extends in a direction in which the screen assembly is to be tensioned to secure the screen assembly to the screening machine.

31. The screen assembly according to claim 29, wherein the reinforcing member is attached to a plurality of screen elements that extend through the screen assembly in the direction in which the screen assembly is to be tensioned.

32. The screen assembly according to claim 29, wherein, The reinforcing member is attached to at least one of the plurality of screen elements by embedding the reinforcing member in the material of at least one of the plurality of screen elements.

33. The screen assembly according to claim 29, wherein, The reinforcing member is attached to at least one of the plurality of screen elements by an adhesive.

Images