Sanitary pit liner system and method of installing the same

Abstract

A sanitary pit liner system for collection of human waste in developing countries includes a plurality of curved, interlocking pit liner segments that snap together to form a cylindrical pit liner, a plurality of curved, interlocking dome segments that snap together to form a dome, a gasket, a squat plate and squat pan user interface or a one-piece toilet user interface. A method of installing a sanitary pit liner system is also disclosed.

Description

Attorney Docket No. 105224-431492-1-SAN1TARY PIT LINER SYSTEM AND METHOD OF INSTALLING THE SAME

[0001] This application claims priority to U.S. Provisional Application No. 63 / 706,580 filed on October, 11, 2024, which is incorporated by reference herein in its entirety.BACKGROUND

[0002] While humanitarian organizations and governments have made great strides in providing clean drinking water to communities in developing countries, for many years sanitation issues were largely ignored. Recently, the devastating effects of poor sanitation have begun to receive more attention. According to the World Health Organization (World Health Organization, n.d.) poor sanitation was responsible for 564,000 deaths, independent of deaths from unsafe drinking water or poor hygiene. WHO also noted that in 2022, 43% of the world's population did not have access to safely managed sanitation.

[0003] WHO reports that there are many benefits to better sanitation, primarily the reduction in diarrheal diseases and lower healthcare costs associated with these diseases. Additional benefits include reduced cases of intestinal worms, improved dignity, and potential recovery of soil nutrients from excreta.

[0004] While the provision of clean water is a major focus of development efforts, good sanitation hardware and practices are also important to maintain the health and dignity of a community. Many technologies are available to aid in promoting good sanitation practices. Of these technologies, the simple pit latrine often provides the best solution for communities in developing countries in terms ofAttorney Docket No. 105224-431492-2- low cost, simple technology, and effectiveness. Potential issues with the pit latrine include bad odors, collapse of the pit, contamination of groundwater near a water point, and pests such as insects and vermin. What is needed are additions to the technology of the pit latrine.SUMMARY

[0005] This disclosure addresses sanitation and hygiene challenges facing rural and periurban (suburban) communities in developing countries by providing an affordable, reliable, and safe latrine option. The cylindrical corrugated pit liner stabilizes the latrine against horizontal and vertical soil compressive loads, while the upper dome provides a stable and robust transition from the top of the pit liner to the user interface, improving user safety. The incorporation of a squat plate and squat pan with a counter- weighted trap door minimizes odor from the pit and reduces the transmission of disease from crawling or flying insects. The entire system can be snapped together without tools and the components stack / nest well to facilitate storage and shipping.

[0006] In one aspect, a sanitary pit liner system includes a plurality of curved interlocking liner segments. The liner segments snap together to form a cylindrical pit liner to collect urine and solid excrement.

[0007] In another aspect, a sanitary pit liner system includes a plurality of curved interlocking dome segments. The dome segments snap together to form an annular dome through which urine and solid excrement pass to a lined collection pit in stable or unstable soils.Attorney Docket No. 105224-431492-3-

[0008] In another aspect, a sanitary pit liner system includes a cylindrical pit liner to collect urine and solid excrement, the pit liner including a plurality of snapped- together, curved, interlocking liner segments. The system also includes an annular dome secured to the pit liner system through which urine and solid excrement pass into the pit liner system. The annular dome includes a plurality of snapped-together, curved, interlocking dome segments. The system also includes one of a squat plate or a one-piece molded toilet seat secured to the annular dome through which urine and solid excrement pass into the annular dome.

[0009] The sanitary pit liner system may also include a gasket positioned between the annular dome and the one of squat plate or the one-piece molded toilet seat.

[0010] In an embodiment, the plurality of interlocking liner segments have coincident axial convolutions on the inner and outer surfaces to stiffen the segments from external loads.

[0011] In another embodiment, the plurality of interlocking liner segments have a wide circumferential flange at upper and lower axial locations to stiffen the segments from external loads.

[0012] The plurality of curved interlocking liner segments may be stacked for storage, shipping, or transport such that an inner curved surface of a first curved interlocking segment is stacked closely to an outer curved surface of an identical second curved interlocking segment.Attorney Docket No. 105224-431492-4-

[0013] In an embodiment, each interlocking liner segment includes a plurality of holes which extend from the inner curved surface to the outer curved surface of each interlocking segment.

[0014] The plurality of holes may cover 2-10 % of the interlocking liner segment surface area for drainage of liquids.

[0015] In an embodiment, each of the interlocking liner segments has a plurality of tabs and openings in an axial direction to allow the tabs on a first curved interlocking segment to latch into the openings of a second curved interlocking segment.

[0016] A first and second interlocking liner segments are latched to a third interlocking line segment to form a cylindrical pit liner ring.

[0017] In an embodiment, each interlocking liner segment has a nominal wall thickness of 2-10 mm.

[0018] In an embodiment, each interlocking liner segment has a height of 0.25- 1.0 meters.

[0019] In an embodiment, each interlocking liner segment has a curvilinear width of 0.25-2.0 meters.

[0020] In an embodiment, each interlocking liner segment has a radius of curvature of 0.25-2.0 meters.

[0021] In an embodiment, a plurality of upper tabs on a first cylindrical pit liner ring latch into lower openings in a second cylindrical pit liner ring to increase the axial height of the pit liner.Attorney Docket No. 105224-431492-5-

[0022] In an embodiment, the plurality of interlocking dome segments have coincident radial convolutions on inner and outer surfaces to stiffen the segments from external loads.

[0023] In another embodiment, the plurality of interlocking dome segments have a circumferential flange at a lower axial location to stiffen the segments from external loads.

[0024] The plurality of curved interlocking dome segments may be stacked for storage, shipping, or transport such that an inner curved surface of a first curved interlocking domed segment is stacked closely to an outer curved surface of an identical second curved interlocking dome segment.

[0025] In an embodiment, each of the plurality of interlocking domed segments includes a plurality of tabs and openings in an axial direction to allow the tabs on a first curved interlocking dome segment to latch into the openings of a second curved interlocking dome segment.

[0026] In an embodiment, first and second interlocking dome segments are latched to a third interlocking dome segment to form an annular dome.

[0027] In an embodiment, each of the plurality of interlocking dome segments has a nominal wall thickness of 2-10 mm.

[0028] In an embodiment, each of the plurality of interlocking dome segments has a height of 0.15-1.0 meters.

[0029] In another embodiment, each of the plurality of interlocking dome segments has a curvilinear width of 0.25-2.0 meters.Attorney Docket No. 105224-431492-6-

[0030] Each of the plurality of interlocking dome segments may have a radius of curvature of 0.25-2.0 meters.

[0031] In an embodiment, a plurality of openings on a lower surface of an annular dome latch into a plurality of tabs on the upper surface of a cylindrical pit liner ring.

[0032] According to another aspect, a method of installing a sanitary pit liner system includes digging a pit in soil, snapping together a plurality of curved interlocking liner segments to create a pit liner, and installing the pit liner in the dug pit. The method also includes snapping together a plurality of curved interlocking dome segments to create an annular dome, installing the annular dome on the pit liner, and installing one of a squat plate or a one-piece molded toilet on the installed annular dome.

[0033] Snapping together the plurality of liner segments may include positioning one or more tabs in one or more openings in the liner segments to latch the liner segments together in both circumferential and axial directions.

[0034] Snapping together the plurality of dome segments may include positioning one or more tabs in one or more openings in the dome segments to latch the dome segments together in both circumferential and axial directions.BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The detailed description particularly refers to the following figures, in which:

[0036] FIG. 1 is a perspective view of a sanitary pit liner system;Attorney Docket No. 105224-431492-7-

[0037] FIG. 2 is an exploded perspective view of the sanitary pit liner system of FIG. 1;

[0038] FIG. 3 is a perspective view of a curved interlocking pit liner segment of the sanitary pit liner system of FIG. 1;

[0039] FIG. 4 is a view similar to FIG. 4, but showing the liner segment rotated relative to the view of FIG. 4;

[0040] FIG. 5 is a perspective view showing the curved interlocking pit liner segments nested for storage and shipping;

[0041] FIG. 6 is a fragmentary perspective view showing the curved interlocking pit liner segments being interlocked;

[0042] FIG. 7 is a front view of a curved interlocking dome segment of the sanitary pit liner system of FIG. 1;

[0043] FIG. 8 is a perspective view showing curved interlocking dome segments nested for storage and shipping;

[0044] FIG. 9 is a fragmentary perspective view showing the curved interlocking dome segments being interlocked;

[0045] FIG. 10 is a perspective view of a curved interlocking dome segment with a wide support flange and ribs;

[0046] FIG. 11 is a fragmentary perspective view showing a squat plate, a squat pan, and a vent pipe option secured to the dome;

[0047] FIG. 12 is a fragmentary perspective view showing a molded toilet option secured to the dome; andAttorney Docket No. 105224-431492-8-

[0048] FIG. 13 illustrates a process for assembling and installing the sanitary pit liner system of FIG. 1.DETAILED DESCRIPTION OF THE DRAWINGS

[0049] Referring now to FIGS. 1 and 2, two arrangements of a sanitary pit liner system are shown - one with a short dome (FIG. 2) and another with a tall dome (FIG. 1). Other than the height of the dome, the two systems are substantially the same. The sanitary pit liner system includes a plurality of curved interlocking pit liner segments 100, a plurality of curved interlocking dome segments 200, a gasket 300, a squat plate 400, and a squat pan 500. The pit liner segments 100 may be perforated to allow the transmission of liquids out of the pit liner and into the surrounding soil. The gasket 300 seals the squat plate 400 to the dome 200 to prevent the passage of crawling and flying insects. The squat pan 500 may contain a counter- weighted trap door (not shown) to minimize the transmission of odors and flying insects from the inside of the pit to the outside of the pit.

[0050] As shown in FIGS. 3 and 4, the curved interlocking pit liner segment 100 includes a plurality of perforations 140. The pit liner segment 100 has an inner surface and an outer surface with a uniform wall thickness. The pit liner segment 100 contains corrugations 110 to increase stiffness (e.g., radial stiffness and / or circumferential stiffness) to externally applied soil loads. The pit liner segment 100 contains an upper flange 120 and lower flange 130 to increase stiffness (e.g., radial stiffness and / or circumferential stiffness). The lower flange 130 nests into the upper flange 120 when the pit liner rings are stacked sequentially. The plurality ofAttorney Docket No. 105224-431492-9- perforations 140 extend from the inner curved surface to the outer curved surface of each interlocking segment. The plurality of perforations 140 may take up 2-10% of the curved interlocking segment 100 surface area for drainage of liquids to the soil.

[0051] As shown in FIG. 5, a plurality of the curved interlocking pit liner segments 100 may be nested closely for storage and shipping. The inner curved surface of a first curved interlocking segment is stacked closely to, and / or in contact with, an outer curved surface of an identical second curved interlocking segment.

[0052] FIG. 6 illustrates the curved interlocking pit liner segments 100 during interlocking, showing a plurality of circumferentially-oriented tabs 150 and a plurality of circumferentially oriented openings 160. Also shown is a plurality of axial tabs 170 and a plurality of axial openings 180. During interlocking, the interlocking circumferential tabs 150 are received into the circumferential openings 160, and interlocking axial tabs 170 are received into the axial openings 180. In particular, each axial tab 170 inserts into two axial openings 180 to improve interlocking strength and assist in maintaining the connection between circumferentially contiguous interlocking pit liner segments 100. Each interlocking circumferential tab 150 may include a cantilevered distal end configured to extend through and past an end of a corresponding circumferential opening 160. Each circumferential opening 160 is configured to receive an interlocking circumferential tab 150.

[0053] Referring not to FIG. 7, a front view of a curved interlocking dome segment 200 is shown. A plurality of axial convolutions 210 increase the axial and circumferential stiffness of the dome segment 200. A top flange 220, forming a ringAttorney Docket No. 105224-431492-10- once the dome is assembled, provides an attachment surface to the user interface (e.g., a squat plate or toilet seat). The bottom flange 230, forming a ring once the dome is assembled, nests into the top surface flange 120 of the curved interlocking pit liner 100.

[0054] As shown in FIG. 8, a plurality of the curved interlocking dome segments 200 may be nested closely for storage and shipping. In doing so, the inner curved surface of a first curved interlocking dome segment is stacked closely to, and / or in contact with, an outer curved surface of an identical second curved interlocking dome segment.

[0055] Referring now to FIG. 9, the curved interlocking dome segments 200 are shown being interlocked to one another. The dome segments 200 have a plurality of axial tabs 240 and a plurality of axial openings 250. Each axial opening 250 is configured to receive an axial tab 240. Also shown is a plurality of axial openings 260 that interlock with the axial tabs 170 of the curved interlocking pit liner segments 100 (see, e.g., FIG. 6). Each axial tab 170 of the contiguous / uppermost interlocking pit liner segment 100 inserts into two axial openings 260 to improve interlocking strength and assist in maintaining the connection between circumferentially contiguous interlocking dome segments 200.

[0056] Illustratively, FIG. 10 shows a curved interlocking dome segment with a wide support flange 240 and ribs 250. This is a second arrangement of the curved interlocking dome segment 200, which is used to provide vertical support in stable soil pits without a pit liner, reducing the cost of the installation. That is, the dome 200 may be used without a pit liner where the soil is stable enough to support theAttorney Docket No. 105224-431492-11- dome alone (e.g., clay soil). Such liner-less pits may be stepped to provide a circular soil shelf upon which support flange 240 rests. Support ribs 250 provide axial support to support flange 240.

[0057] As shown in FIG. 11, a squat plate 400, squat pan 500, and vent pipe 700 may be secured to the dome 200. Although not visible in FIG. 11, the gasket 300 seals the squat pan 400 to the curved interlocking dome 200. This is an arrangement to improve pit ventilation to reduce odor to the user and minimize flying insects. The top of the vent pipe 700 is typically supported by the roof of the pit latrine structure. The vent pipe 700 extends through an aperture in the annular dome 200. The squat plate 400 rests upon the rim of a hole at the center / top of the annular dome 200. The squat pan 500 is inset into the squat plate 400.

[0058] As shown in FIG. 12, a molded toilet 600 may be secured to the annular dome 200 in lieu of the squat plate. The gasket 300 (not shown in FIG. 12) seals the one-piece molded toilet 600 to the annular dome 200. The molded toilet 600 rests upon the rim of a hole at the center / top of the annular dome 200.

[0059] A method of installing the sanitary pit liner system is shown in FIG. 13. The pit is first dug and then a plurality of curved, interlocking pit liner segments are latched together to form a cylindrical pit liner ring. Thereafter, a plurality of pit liner rings are latched together to form a full pit liner, which is then lowered into the pit. The assembled pit liner may range from 1-5 meters in depth. Once assembled, an annular dome is then latched onto the top surface of the pit liner. A gasket and user interface is then installed. The user interface may be a squat plate and squat pan,Attorney Docket No. 105224-431492-12- or a molded toilet seat. The gasket and user interface are fit to a hole at the center / top of the annular dome.

[0060] While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.

[0061] There are a plurality of advantages of the present disclosure arising from the various features of the apparatus, system, and method described herein. It will be noted that alternative embodiments of the apparatus, system, and method of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the apparatus, system, and method that incorporate one or more of the features of the present invention and fall within the spirit and scope of the present disclosure.

Claims

Attorney Docket No. 105224-431492-13-WHAT IS CLAIMED IS:

1. A sanitary pit liner system comprising: a cylindrical pit liner to collect urine and solid excrement comprising a plurality of snapped-together, curved, interlocking liner segments, an annular dome secured to the pit liner system through which urine and solid excrement pass into the pit liner system, the annular dome comprising a plurality of snapped-together, curved, interlocking dome segments, one of a squat plate or a one-piece molded toilet seat secured to the annular dome through which urine and solid excrement pass into the annular dome.

2. The sanitary pit liner system of claim 1, further comprising a gasket positioned between the annular dome and the one of squat plate or the one- piece molded toilet seat.

3. The sanitary pit liner system of any preceding claim, wherein the plurality of interlocking liner segments have coincident axial convolutions on the inner and outer surfaces to stiffen the segments from external loads.

4. The sanitary pit liner system of any preceding claim, wherein the plurality of interlocking liner segments have a wide circumferential flange at upper and lower axial locations to stiffen the liner segments from external loads.

5. The sanitary pit liner system of any preceding claim, wherein the plurality of interlocking liner segments can be stacked for storage, shipping, orAttorney Docket No. 105224-431492-14- transport such that an inner curved surface of a first interlocking liner segment is stacked closely to an outer surface of an identical second interlocking liner segment.

6. The sanitary pit liner system of any preceding claim, wherein each interlocking liner segment includes a plurality of holes which extend from the inner curved surface to the outer curved surface of each interlocking liner segment.

7. The sanitary pit liner system of claim 6, wherein the plurality of holes covers 2-10 % of the curved interlocking liner segment surface area for drainage of liquids.

8. The sanitary pit liner system of any preceding claim, wherein each of the interlocking liner segments has a plurality of tabs and openings in an axial direction to allow the tabs on a first interlocking liner segment to latch into the openings of a second interlocking liner segment.

9. The sanitary pit liner system of claim 8, wherein a first and second interlocking liner segments are latched to a third interlocking liner segment to form a cylindrical pit liner ring.

10. The sanitary pit liner system of any preceding claim, wherein each interlocking liner segment has a nominal wall thickness of 2-10 mm.Attorney Docket No. 105224-431492-15-11. The sanitary pit liner system of any preceding claim, wherein each interlocking liner segment has a height of 0.25-1.0 meters.

12. The sanitary pit liner system of any preceding claim, wherein each interlocking liner segment has a curvilinear width of 0.25-2.0 meters.

13. The sanitary pit liner system of any preceding claim, wherein each interlocking liner segment has a radius of curvature of 0.25-2.0 meters.

14. The sanitary pit liner system of any preceding claim, wherein a plurality of upper tabs on a first cylindrical pit liner ring latch into lower openings in a second cylindrical pit liner ring to increase the axial height of the pit liner.

15. The sanitary pit liner system of any preceding claim, wherein each of the plurality of interlocking dome segments has coincident radial convolutions on inner and outer surfaces to stiffen the segments from external loads.

16. The sanitary pit liner system of any preceding claim, wherein each of the plurality of interlocking dome segments has a circumferential flange at a lower axial location to stiffen the segments from external loads.

17. The sanitary pit liner system of any preceding claim, wherein the plurality of curved interlocking dome segments can be stacked for storage, shipping, or transport such that an inner curved surface of a first curved interlocking domedAttorney Docket No. 105224-431492-16- segment is stacked closely to an outer curved surface of an identical second curved interlocking dome segment.

18. The sanitary pit liner system of any preceding claim, wherein each of the plurality of interlocking domed segments comprises a plurality of tabs and openings in an axial direction to allow the tabs on a first curved interlocking dome segment to latch into the openings of a second curved interlocking dome segment.

19. The sanitary pit liner system of any preceding claim, wherein first and second curved interlocking segments are latched to a third curved interlocking dome segment to form an annular dome.

20. The sanitary pit liner system of any preceding claim, wherein each of the plurality of interlocking dome segments has a nominal wall thickness of 2-10 mm.

21. The sanitary pit liner system of any preceding claim, wherein each of the plurality of interlocking dome segments has a height of 0.15-1.0 meters.

22. The sanitary pit liner system of any preceding claim, wherein each of the plurality of interlocking dome segments has a curvilinear width of 0.25-2.0 meters.Attorney Docket No. 105224-431492-17-23. The sanitary pit liner system of any preceding claim, wherein each of the plurality of interlocking dome segments has a radius of curvature of 0.25- 2.0 meters.

24. The sanitary pit liner system of any preceding claim, wherein a plurality of openings on a lower surface of an annular dome latch into a plurality of tabs on the upper surface of a cylindrical pit liner ring.

25. A method of installing a sanitary pit liner system comprising: digging a pit in soil, snapping together a plurality of curved interlocking liner segments to create a pit liner, installing the pit liner in the dug pit, snapping together a plurality of curved interlocking dome segments to create an annular dome, installing the annular dome on the pit liner, and installing one of a squat plate or a one-piece molded toilet on the installed annular dome.

26. The method of claim 25, wherein snapping together the plurality of liner segments comprises positioning one or more tabs in one or more openingsAttorney Docket No. 105224-431492-18- in the liner segments to latch the liner segments together in both circumferential and axial directions.

27. The method of claim 25, wherein snapping together the plurality of dome segments comprises positioning one or more tabs in one or more openings in the dome segments to latch the dome segments together in both circumferential and axial directions.

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