Method and apparatus for producing textured geomembrane
The method and apparatus for manufacturing textured geomembranes with angled projections address the issue of non-uniform bending and engagement, resulting in stable tufted geosynthetic turf systems resistant to downslope movement and wind uplift.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- WATERSHED GEOSYNTHETICS LLC
- Filing Date
- 2025-12-03
- Publication Date
- 2026-06-11
AI Technical Summary
Existing methods for manufacturing elongated geomembranes with textured projections suffer from unsatisfactory bending of projections with non-uniform angled orientations and inadequate engagement with the backing sheet, leading to movement and tear issues in tufted geosynthetic turf.
A method and apparatus for manufacturing a textured geomembrane involving extrusion through rollers with recesses, followed by bending projections using an elongated member angled relative to the sheet, and tensioning to achieve angled projections that engage with tufted geotextiles, resisting downslope movement.
The method and apparatus produce geomembranes with uniformly angled projections that effectively resist downslope movement and wind uplift, enhancing the stability and integrity of tufted geosynthetic turf systems.
Smart Images
Figure US2025057820_11062026_PF_FP_ABST
Abstract
Description
TEXTURED GEOMEMBRANE AND METHODTechnical Field
[0001] The present invention relates to a method of manufacturing a textured geomembrane for overlying a ground surface as a cover sheet to restrict subsurface inflow of ambient environmental water. More particularly, the present invention relates to methods of manufacturing an elongated geomembrane sheet having a textured field of space-apart tapered projections and installations of the manufactured textured geomembrane with tufted geotextiles for ground covering purposes.Background Of The Invention
[0002] Elongated geomembranes are used at landfills or waste sites as overlying covers for restricting inflow of ambient environmental water such as from rain and snow precipitation into the soil below grade or into below surface water tables. The geomembranes often are overlaid with tufted geosynthetic turf of a backing sheet tufted with yarns to have a field of tufts extending as synthetic grass blades. The tufted geosynthetic turf provides an attractive appearance for large land sites while reducing periodic vegetation maintenance required for earth-covered sites.
[0003] Large-area ground-covering tufted geosynthetic turf is susceptible to movement induced by thermal expansion and contraction and shear forces from wind and ambient water flow. The movement is typically down-slope and creates ridges in the geosynthetic turf and stressed areas that form openings or tears in the backing sheet. To reduce movement, tufted geosynthetic ground cover is ballasted with distributed granular material such as sand. The granular material is susceptible to migration in response to shear forces from flow of ambient environment water and4867-1895-2400vl2171320-000177 12 / 02 / 2025wind. To restrict migration, the granular material may include a cementitious mixture to lock the distributed granular material together and to the extending tufts.
[0004] Alternatively, an underlying geomembrane may be overlaid on the ground surface to mechanically engage the ground and the overlying geosynthetic turf. In a particular application, the geomembrane includes a field of tapered vertically extending projections or spikes that engage an opposing back surface of the backing sheet. The tapered spikes are formed using conventional extruded sheet manufacturing apparatus having opposing rollers. At least one roller defines spaced-apart recesses that receive molten polymeric material that is pulled outwardly during rotation to define the spike projection extending from the extruded sheet. A second roller spaced in the machine direction rolls against the spike projections to bend the spike projections. The installed geomembrane resists down-slope movement of the overlying geosynthetic tuft.
[0005] While the roller bends the formed projections extending from the surface of the geomembrane sheet, there are unsatisfactory drawbacks. The projections may be unsatisfactorily bent with non-uniform angled orientations and further, the opposing rollers may rather instead mash the projections into the thickness of the extruded geopolymer sheet and thus insufficiently angle the projections.
[0006] Accordingly, there is a need in the art for an improved method of manufacturing an elongated geomembrane sheet having a textured field of angle-oriented tapered projections. It is to such that the present invention is directed.4867-1895-2400vl2171320-000177 12 / 02 / 2025Brief Summary Of The Invention
[0007] The present invention meets the need in the art by providing a method of manufacturing an elongated geomembrane sheet having a textured field of tapered projections.
[0008] More particularly, the present invention provides a method for forming a textured geomembrane, comprising the steps of:(a) extruding a continuous sheet of a polymeric material in a machine direction;(b) moving the continuous sheet between opposing rollers with at least one roller textured with a plurality of spaced-apart recesses, each recess for receiving a portion of the polymeric material therein and upon continued rotation of said textured roller said portion of the polymeric material extracted therefrom to define a respective projection conforming in shape to the recess and extending from a surface of the continuous sheet a height to a distal tip; and(c) moving the continuous sheet relative to an elongated member orientated at an oblique angle, said elongated member having a lower end proximate the surface of the continuous sheet and vertically spaced therefrom intermediate the surface and the height of the respective projection, whereby each of the projections impacting the elongated member bends in a direction while the projection slides thereon and along the lower end for defining a bent shape to each of the plurality of projections with the distal tip pointing on a line oriented at an oblique angle relative to the continuous sheet.
[0009] The method further comprising the step of tensioning the continuous sheet as the projections bend upon pressing contact with the bending contact surface of the elongated member.4867-1895-2400vl2171320-000177 12 / 02 / 2025
[0010] The method wherein tensioning comprises passing the continuous sheet between a second pair of rollers that grippingly engage opposing surfaces of the continuous sheet, said opposing rollers rotating with an annular velocity greater than the machine direction moving velocity of the continuous sheet.
[0011] The method further comprising the step of biasing the elongated member towards the continuous sheet.
[0012] The method further comprising the step of applying a compressive force by a spring bearing on the elongated member for biasing towards the continuous sheet.
[0013] The method further comprising the step of attaching a mass to the elongated member for biasing towards the continuous sheet.
[0014] The method wherein the height of the respective projection forms in a range from 10 mil (0.26 mm) to 500 mil (12.7 mm).
[0015] The method wherein the height of the respective projection forms in a range from 20 mil (0.51 mm) to 350 mil (9.1 mm).
[0016] The method wherein the extrusion forms the continuous sheet with a thickness in a range of 25 mil to 150 mil.
[0017] In another aspect, the present invention provides an apparatus for forming a textured geomembrane, comprising an extruder for receiving a supply of a polymeric material for extruding an elongated sheet and a pair of opposing rollers with at least one roller textured with a plurality of spaced-apart recesses, each recess for receiving a portion of the polymeric material of the4867-1895-2400vl2171320-000177 12 / 02 / 2025extruded elongated sheet and upon continued rotation of said roller said portion of the polymeric material extracted therefrom for defining a respective projection conforming in shape to the recess and extending from a surface of the continuous sheet a height to a distal tip. An elongated member disposed transverse to a machine direction of a movement of the elongated sheet from the extruder, said elongated member having a lower end for disposing vertically spaced from the surface of the continuous sheet intermediate the surface and the height of the respective projection, whereby upon operation of the extruder each of the projections being impacted by the elongated member for bending in a direction opposite the machine direction until the distal tip slidingly contacts said lower edge for defining a bent shape to each of the plurality of projections with the distal tip pointing on a line oriented at an oblique angle relative to the continuous sheet.
[0018] The apparatus further comprising a tensioner for tensioning the continuous sheet as the projections bend upon pressing contact with the elongated member.
[0019] The apparatus wherein the tensioner comprises a second pair of rollers for grippingly engaging opposing surfaces of the continuous sheet, said opposing rollers for rotating with an annular velocity greater than the machine direction moving velocity of the continuous sheet.
[0020] The apparatus further comprising a spring bearing on the elongated member for biasing towards the continuous sheet.
[0021] The apparatus further comprising a mass body attached to the elongated member for biasing towards the continuous sheet.
[0022] The apparatus wherein the rollers form the respective projection with a height in a range from 10 mil (0.26 mm) to 500 mil (12.7 mm).4867-1895-2400vl2171320-000177 12 / 02 / 2025
[0023] The apparatus wherein the rollers form the respective projection with a height in a range from 20 mil (0.51 mm) to 350 mil (9.1 mm).
[0024] The apparatus wherein the extruder forms the continuous sheet with a thickness in a range of 25 mil to 150 mil.
[0025] Objects, advantages, and features of the present invention will become apparent upon a reading of the following detailed description in reference to the drawings.Brief Description Of The Drawings
[0026] Fig. 1 illustrates a geomembrane having a textured field of angularly oriented tapered projections in accordance the present invention.
[0027] Fig. 2 illustrates a schematic diagram of a process for manufacturing the geomembrane illustrated in Fig. 1.
[0028] Figs. 3A, 3B, and 3C illustrate in detailed view the projection bending steps of the manufacturing process.
[0029] Fig. 4 illustrates a perspective view of the geomembrane manufactured according to the present invention deployed over a ground surface to provide the textured field of tapered projections and engaged to an overlying tufted geotextile as a ground cover system for land site covers.
[0030] Fig. 5 is a detailed view of the ground cover system illustrated in Fig. 4 having the tufted geotextile overlying the geomembrane manufactured according to the present invention and4867-1895-2400vl2171320-000177 12 / 02 / 2025engaged on a back aide to the textured field of the tapered projections for frictional interface engagement of the tufted geotextile and the geomembrane.Detailed Description
[0031] With reference to the drawings, in which like parts have like identifiers, the present invention provides a process for manufacture of an elongated geomembrane sheet 10 having a field 14 of a plurality of tapered projections 18 each extending from a surface 20 of the sheet to a distal tip 24 vertically to a height therefrom, which process further includes the step of then bending the tapered projections 18 to have the respective distal tip 24 orientated on a line 28 at an oblique angle 30 relative to the geomembrane sheet. The bent tapered projections 18 may be bent angularly or arcuately, which orients the tapered projections with the respective distal tip pointing at the oblique angle 30 and lower than the height of the vertical unbent tapered projections.
[0032] Fig. 2 illustrates a schematic diagram of an apparatus 50 for manufacturing the geomembrane sheet 10 illustrated in Fig. 1. The manufacturing apparatus 50 includes a supply hopper 52 that receives a supply of polymeric material such as beads, pellets, chips, or particulates. The hopper 52 feeds the polymeric material to a heated extruder 54 having an extruder port from which flows a continuous stream 55 of the melted polymeric material. The stream 55 flows between opposing rollers 56, 58 for extruding the polymeric material as the elongated sheet 10 moving continuously on a carrying conveyor 59. The rollers 56, 58 are vertically spaced apart to define a thickness for the elongated sheet 10. Downstream spaced-apart rollers (not illustrated) may engage opposing surfaces of the extruded geomembrane sheet 10 to guide the moving sheet in the machine direction longitudinally on the conveyor as the geomembrane sheet cools and4867-1895-2400vl2171320-000177 12 / 02 / 2025hardens to a flexible elongated sheet. A roller device 60 receives the leading end of the elongated sheet and rotates a spindle 62 to roll the elongated sheet into a roll for shipping and handling at a land site for installation.
[0033] The surface of the roller 56 defines a plurality of spaced-apart cavities or recesses 64. Each of the cavities 64 is a mold with an inner wall in the shape of the tapered projection 18. In the illustrated embodiment, the cavity 64 extends inwardly of the roller 56 to a tapered distal end. During operation of the extrusion apparatus 50, the roller 56 contacts the molten extrudate polymeric material flowing from the extruder port. As the roller 56 rotates in relation to the opposing roller 58 and into contact with the molten extrudate polymeric material, the respective cavities 64 receive a portion of the extrudate polymeric material for forming the tapered projection 18. The tapered projection 18 forms by the extrudate polymeric material pulling out of the respective cavity 64 upon the continued rotation of the roller 56. The tapered projections 18 stand vertical relative to the surface of the geomembrane sheet 14 and extend to the height.
[0034] The apparatus 50 further includes an elongated bending member 70 between the extruder 54 and the roller device 60. The elongated bending member 70 has a lower end 72 and a bending contact surface 74. The elongated bending member 70 is disposed transverse to a longitudinal axis of the conveyor 59 that carries the elongated geomembrane sheet 10 longitudinally from the extruder. The lower end 72 of the elongated bending member 70 is proximate an upper surface of the elongated geomembrane sheet 10. A loading device 76 applies a load to the elongated bending member 70. In an embodiment, the loading device 74 comprises a spring that applies compression force downwardly against the elongated bending member. In another embodiment, the loading device 70 is a mass body attached to the elongated bending member 70. The spring force or mass is selectable for equating to forming different angles for the4867-1895-2400vl2171320-000177 12 / 02 / 2025bent projections of the textured geomembrane. Further, the elongated bending member 70 is selectively positionable at an oblique angle 77 facing towards the moving elongated geomembrane sheet 10. The elongated bending member 70 is selectively positioned vertically spaced 78 from the surface of the elongated geomembrane sheet 10 intermediate the surface and a predetermined height.
[0035] Figs. 3A, 3B, and 3C illustrate in detailed view the projection bending steps of the manufacturing process according to the present invention. As shown in Fig. 3A, the elongated bending member 70, angled facing towards the extruder 54, is selectively positioned a predetermined height 78 vertically spaced from the surface of the elongated geomembrane sheet 10 intermediate the surface and the height of the distal tip 24. The lower end 72 is thereby positioned lower than the height of the distal tip 24 of the tapered projections 18 extending vertically from the elongated geomembrane sheet 10 and spaced above the surface of the elongated geomembrane sheet 10. The conveyor 59 carries the elongated geomembrane sheet 10 longitudinally from the extruder 54. The distal tip 24 of the tapered projection 18 impacts on the bending contact surface 74 intermediate opposing upper and lower edges of the elongated bending member 70, as shown in Fig. 3B. The force of the moving impact causes the tapered projection 18 to bend towards the extruder 54 in a longitudinal direction opposite the direction of travel of the conveyor. As the conveyor continues movement away from the extruder 54, the distal end portion of the tapered projection 18 slides along the bending contact surface 74. The distal end portion reaches the surface of the lower end 72 of the elongated bending member 70. The distal end portion slides along the surface of the end 72 as the conveyor moves the elongated geomembrane sheet 10 longitudinally in a machine direction away from the extruder 54 past the 4867-1895-2400vl 2171320-000177 12 / 02 / 2025elongated bending member 70. The respective tapered projection 18 slides off of the surface 72 as a bent projection 18 in the field 14 of projections.
[0036] The elongated bending member 70 may be selectively positioned intermediate the extruder 54 and the roller device 60. The elongated geomembrane sheet 10 and the tapered projections 18 begin cooling and solidifying upon exiting the extruder 54. The bending of the tapered projections 18 may be more readily accomplished with the elongated bending member 70 closer to the extruder 54. Bending of the tapered projections 18 is accomplished with the tapered projections still cooling or when solidified after cooling.
[0037] The elongated bending member 70 may be selectively positioned vertically spaced 78 from the surface of the elongated geomembrane sheet 10. As noted above, the elongated bending member 70 is positioned with the lower edge 72 proximate the surface between the surface of the elongated geomembrane sheet 10 and the height of the distal tip 24 of the extending tapered projection 18. Positioning the elongated bending member 70 with a small vertical gap 78 closer to the surface bends the tapered projection 18 lower while a larger vertical gap upwardly towards the height of the tapered projections forms the bend closer to the distal tip of the tapered projections.
[0038] Fig. 4 illustrates a perspective view of the geomembrane 10 manufactured according to the present invention deployed over a ground surface 82 to provide the textured field 14 of tapered projections 18 and engaged to an overlying tufted geotextile 84 as a ground cover system generally 85 for a cover for a land site 80. The geomembrane 10 installs by unrolling a roll of the elongated geomembrane sheet over the surface 82. Edges of adjacent elongated geomembrane 10 overlap as shown by dashed line or alternatively j oin together adhesively to sealingly join the adjacent sheets 4867-1895-2400vl 2171320-000177 12 / 02 / 2025together, and thereby restrict inflow of ambient environmental water below ground. The geomembrane 10 thereby covers the surface 82 of a ground site 80 with the textured field 14 of the plurality of bent tapered projections 18. The tufted geotextile 84 overlies the geomembrane 10. The tufted geotextile 84 is similarly provided as a roll and is unrolled over the installed geomembrane 10. A back side of the tufted geotextile 84 mechanically engages the respective tapered projections 18 for a high frictional interface resistant to downslope movement and slippage of the tufted geotextile relative to the geomembrane. The tufted geotextile 84 comprises a backing 86 tufted with spaced-apart yams to define a plurality of tufts 88 of simulated grass blades extending from an upper surface.
[0039] Fig. 5 is a detailed view of the ground cover system 85 illustrated in Fig. 4 having the tufted geotextile 84 overlying the geomembrane 10 manufactured according to the present invention and engaged on the back side to the textured field 14 of the tapered projections 19 for frictional interface engagement of the tufted geotextile and the geomembrane. The engaged tufted geotextile 84 and geomembrane 10 cooperatively provide the ground cover system 85 with high frictional interface engagement that resists relative movement of the geotextile 84 relative to the geomembrane 10 and particularly restricts downslope movement such as caused by thermal expansion during daylight and contraction at night while resisting wind uplift shear forces of wind or ambient environmental water flow across the ground cover.
[0040] The elongated bending member 70 in the illustrated embodiment illustrated in Fig. 2 defines a continuous edge and extends transverse to a machine direction laterally between opposing sides of the conveyor 59 carrying the geomembrane sheet 10. In an alternate embodiment, the elongated bending member comprises a plurality of independent bending members coaxially aligned and spaced-apart across the transverse width of the geomembrane sheet4867-1895-2400vl2171320-000177 12 / 02 / 202510. In yet another alternative embodiment, the plurality of separate independent bending members are respectively selectively vertically spaced intermediate the surface of the geomembrane sheet and the height of the distal tip of the taper projections, whereby specific areas of the geomembrane sheet are configured for having selective interface friction for the ground cover system of the tufted geosynthetic and the geomembrane sheet overlying a ground surface.
[0041] The geomembrane 10 is calendar manufactured sheet of HDPE or LLDPE with a nominal thickness in a range of 25 mil to 150 mil, and preferably in a range of 30 mil to 100 mil. Outdoor ground cover applications with exposure to extreme weather conditions, such as harsh sunlight, wind, and rain, may necessitate a thicker geomembrane. The tapered projections 18, integral with and extending from the geomembrane 10, are short in stature. Prior to the bending step, the tapered projections 18 are formed with heights in a range of 10 mil (0.26 mm) to 500 mil (12.7 mm), preferably in a range of 20 mil (0.51 mm) to 350 mil (9.1 mm), and more preferably 50 mil (1.28 mm) for a short projecting spike and 175 mil (4.45 mm) for a taller projecting spike. The height of the projection 18 differs with the thickness of the geomembrane 10 as a thicker sheet can more readily form a taller projection. Generally, a shorter projection 18 will have less of an angulation of the tip than a taller projection. The projections 18 are shorter relative to the lengths of the simulated blades of the tufts 88 of the tufted geosynthetic 84. The tufts 88 may have tufted simulated blades 88 extending from the geosynthetic backing 86 in a range from 0.4 inches to 4.0 inches.
[0042] The present invention provides an apparatus for forming a textured geomembrane, comprising an extruder for receiving a supply of a polymeric material and for extruding an elongated sheet with a pair of opposing rollers with at least one roller textured with a plurality of spaced-apart recesses, each recess for receiving a portion of the polymeric material of the extruded4867-1895-2400vl2171320-000177 12 / 02 / 2025elongated sheet and upon continued rotation of said roller said portion of the polymeric material extracted therefrom for defining a respective projection conforming in shape to the recess and extending from a surface of the continuous sheet a height to a distal tip. An elongated member disposed transverse to a machine direction of a movement of the elongated sheet from the extruder, said elongated member having a lower end for disposing vertically spaced from the surface of the continuous sheet intermediate the surface and the height of the respective projection, whereby upon operation of the extruder each of the projections being impacted by the elongated member for bending in a direction opposite the machine direction until the distal tip slidingly contacts said lower edge for defining a bent shape to each of the plurality of projections with the distal tip pointing on a line oriented at an oblique angle relative to the continuous geomembrane sheet 10.
[0043] Further, in an alternate embodiment, a tensioner tensions the continuous geomembrane sheet 10 as the tapered projections 18 bend upon pressing sliding contact with the elongated bending member 70. This is accomplished in an illustrative embodiment with a second pair of opposing rollers proximate the elongate bending member 70. The second rollers grippingly engage opposing surfaces of the continuous geomembrane sheet 10. The second opposing rollers are rotatable with an annular velocity greater than the machine direction moving velocity of the continuous geomembrane sheet, whereby the moving geomembrane sheet is tugged in the machine direction while the tapered projections 18 bendingly slide on bending surface 74 of the bending member 70.
[0044] In another aspect, the present invention provides a method for forming a textured geomembrane, comprising the steps of:(a) extruding a continuous sheet of a polymeric material in a machine direction;4867-1895-2400vl2171320-000177 12 / 02 / 2025(b) moving the continuous sheet between opposing rollers with at least one roller textured with a plurality of spaced-apart recesses, each recess for receiving a portion of the polymeric material therein and upon continued rotation of said textured roller said portion of the polymeric material extracted therefrom to define a respective projection conforming in shape to the recess and extending from a surface of the continuous sheet a height to a distal tip; and(c) moving the continuous sheet relative to an elongated member orientated at an oblique angle, said elongated member having a lower end proximate the surface of the continuous sheet and vertically spaced therefrom intermediate the surface and the height of the respective projection, whereby each of the projections impacting the elongated member bends in a direction while the projection slides thereon and along the lower end for defining a bent shape to each of the plurality of projections with the distal tip pointing on a line oriented at an oblique angle relative to the continuous sheet.
[0045] Further, the continuous geomembrane sheet 10 is tensioned as the tapered projections 18 bend upon pressing contact with the bending contact surface 74 of the elongated bending member 70. This tensioning is accomplished with a pair of opposing second rollers having bearing contact with the geomembrane sheet 10 and rotate with an annular velocity greater than the machine direction moving velocity of the continuous geomembrane sheet. The continuous geomembrane sheet 10 passes between the second pair of rollers and being grippingly engaged on opposing surfaces, the opposing rollers rotatingly tug the geomembrane sheet in the machine direction. The tensioning of the continuous geomembrane sheet 10 facilitates bending of the tapered projections 18 as the tapered projections impact and slide on the bending surface 74.
[0046] In an alternate embodiment, the elongated geomembrane sheet 10 is fixed securely and a movable bridge carries the bending member 70 across the elongated geomembrane sheet with4867-1895-2400vl2171320-000177 12 / 02 / 2025the lower end 72 vertically spaced relative to the distal tips 24, whereby the tapered projections 18 bendingly impact the bending surface 74.
[0047] The foregoing discloses an apparatus and method for forming the continuous elongated geomembrane sheet having the field of tapered projections bent at an oblique angle relative to the elongated geomembrane sheet for ground cover purposes, and it will be readily apparent to those skilled in the art that many modifications and variations can be made therein without departing from the invention as defined by the appended claims.4867-1895-2400vl2171320-000177 12 / 02 / 2025
Claims
ClaimsWhat is claimed is:
1. A method for forming a textured geomembrane, comprising the steps of(a) extruding a continuous sheet of a polymeric material in a machine direction;(b) moving the continuous sheet between opposing rollers with at least one roller textured with a plurality of spaced-apart recesses, each recess for receiving a portion of the polymeric material therein and upon continued rotation of said textured roller said portion of the polymeric material extracted therefrom to define a respective projection conforming in shape to the recess and extending from a surface of the continuous sheet a height to a distal tip; and(c) moving the continuous sheet relative to an elongated member orientated at an oblique angle, said elongated member having a lower end proximate the surface of the continuous sheet and vertically spaced therefrom intermediate the surface and the height of the respective projection, whereby each of the projections impacting the elongated member bends in a direction while the projection slides thereon and along the lower end for defining a bent shape to each of the plurality of projections with the distal tip pointing on a line oriented at an oblique angle relative to the continuous sheet.
2. The method as recited in claim 1, further comprising the step of tensioning the continuous sheet as the projections bend upon pressing contact with the bending contact surface of the elongated member.
3. The method as recited in claim 2, wherein tensioning comprises passing the continuous sheet between a second pair of rollers that grippingly engage opposing surfaces of the continuous4867-1895-2400vl2171320-000177 12 / 02 / 2025sheet, said opposing rollers rotating with an annular velocity greater than the machine direction moving velocity of the continuous sheet.
4. The method as recited in claim 1, further comprising the step of biasing the elongated member towards the continuous sheet.
5. The method as recited in claim 4, further comprising the step of applying a compressive force by a spring bearing on the elongated member for biasing towards the continuous sheet.
6. The method as recited in claim 4, further comprising the step of attaching a mass to the elongated member for biasing towards the continuous sheet.
7. The method as recited in claim 1, wherein the height of the respective projection is in a range from 10 mil (0.26 mm) to 500 mil (12.7 mm).
8. The method as recited in claim 1, wherein the height of the respective projection is in a range from 20 mil (0.51 mm) to 350 mil (9.1 mm).
9. The method as recited in claim 1, wherein the extrusion forms the continuous sheet with a thickness in a range of 25 mil to 150 mil.4867-1895-2400vl2171320-000177 12 / 02 / 202510. An apparatus for forming a textured geomembrane, comprising: an extruder receiving a supply of a polymeric material for extruding an elongated sheet; a pair of opposing rollers with at least one roller textured with a plurality of spaced-apart recesses, each recess for receiving a portion of the polymeric material of the extruded elongated sheet and upon continued rotation of said roller said portion of the polymeric material extracted therefrom for defining a respective projection conforming in shape to the recess and extending from a surface of the continuous sheet a height to a distal tip; and an elongated member disposed transverse to a machine direction of a movement of the elongated sheet from the extruder, said elongated member having a lower end for disposing vertically spaced from the surface of the continuous sheet intermediate the surface and the height of the respective projection, whereby upon operation of the extruder each of the projections being impacted by the elongated member for bending in a direction opposite the machine direction until the distal tip slidingly contacts said lower edge for defining a bent shape to each of the plurality of projections with the distal tip pointing on a line oriented at an oblique angle relative to the continuous sheet.
11. The apparatus as recited in claim 10, further comprising a tensioner for tensioning the continuous sheet as the projections bend upon pressing contact with the elongated member.
12. The apparatus as recited in claim 10, wherein the tensioner comprises a second pair of rollers for grippingly engaging opposing surfaces of the continuous sheet, said opposing rollers for rotating with an annular velocity greater than the machine direction moving velocity of the continuous sheet.4867-1895-2400vl2171320-000177 12 / 02 / 202513. The apparatus as recited in claim 10, further comprising a spring bearing on the elongated member for biasing towards the continuous sheet.
14. The apparatus as recited in claim 10, further comprising a mass body attached to the elongated member for biasing towards the continuous sheet.
15. The apparatus as recited in claim 10, wherein the rollers form the respective projection with a height in a range from 10 mil (0.26 mm) to 500 mil (12.7 mm).
16. The apparatus as recited in claim 10, wherein the rollers form the respective projection with a height in a range from 20 mil (0.51 mm) to 350 mil (9.1 mm).
17. The apparatus as recited in claim 10, wherein the extruder forms the continuous sheet with a thickness in a range of 25 mil to 150 mil.4867-1895-2400vl2171320-000177 12 / 02 / 2025