US20140230137A1

US20140230137A1 - Pour-Flush Latrines, Latrine Pans, Latrine Pan Assemblies, and Related Methods

Info

Publication number: US20140230137A1
Application number: US13/770,923
Authority: US
Inventors: Gregory Gatarz; Daigo Ishiyama; James McHale
Original assignee: AS IP Holdco LLC
Current assignee: Lixil Corp
Priority date: 2013-02-19
Filing date: 2013-02-19
Publication date: 2014-08-21

Abstract

The invention described herein includes a pour-flush latrine pan mountable at a surface that includes a collection basin and a flapper. The collection basin has an upper bowl portion that tapers to an outlet extending through a wall of the collection basin at its lower end. The flapper includes a counterbalance device and a coverplate disposed on opposite sides of a pivot. The coverplate has a shape adapted to cover the outlet of the collection basin when the coverplate is engaged against the lower end of the collection basin. The flapper is pivotally mounted against the collection basin such that the coverplate engages against the lower end of the collection basin when a pivotal force attributable to the counterbalance device is greater than a pivotal force applied to the coverplate that engages the lower end of the collection basin. In an embodiment, the shape of the coverplate defines a channel that engages the lower end of the collection basin about its perimeter when the coverplate is engaged against the lower end of the collection basin

The invention also includes latrine pan assemblies, latrines and methods that employ the latrine pan.

Description

BACKGROUND OF THE INVENTION

It is reported that about 2.5 billion people worldwide do not have access to any type of improved sanitation facility. These individuals suffer significant adverse health effects, including death, as a direct result of a lack of improved sanitation, including toilet facilities. Diarrheal diseases resulting from lack of sanitation are the second leading cause of child deaths in the world, claiming over 700,000 lives per year. The most affected are individuals residing in developing countries, often living in conditions of poverty outside of city centers. Such individuals do not have regular and easy access to a running fresh water supply or to facilities for the sanitary disposal of human excreta.
Because of the very real dangers posed by poor sanitation, the United Nations included access to improved sanitation as part of the Millennium Development Goals (MDGs) established at the Millennium Summit in 2000. Specifically, Goal 7, Target 7c of the MDGs aspires to reduce by half the proportion of people without sustainable access to basic sanitation by the year 2015. “Basic sanitation” requires access to facilities that hygienically separate human excreta from human contact, such as toilets with sewer connections and septic system connections, where feasible, or pour-flush and covered slab latrines in more remote areas.
Traditional, open pit latrines, bucket latrines, and hanging latrines do not meet the criteria of improved sanitation, in part because the hygienic separation of the actual waste products from human contact is not ensured, but also because of the unregulated and uncontrolled release of various sewage-generated gases from these types of latrines. Gases emitted from the decomposing human waste in a leach pit pose, at minimum, an olfactory challenge, as their odor is unpleasant. Of greater significance are the potential adverse health effects of longer term exposure to the sewage gases, in particular to methane, hydrogen sulfide, and ammonia. Exposure to these gases, even in low levels over the long term can result in chronic mucus membrane irritation, cause chronic coughing or sore throat, shortness of breath, and fluid accumulation in the lungs. Other effects may include fatigue, pneumonia, loss of appetite, headaches, irritability, poor memory, and dizziness. At very high concentrations (>300 ppm), hydrogen sulfide can cause loss of consciousness and death.
Pour-flush latrines are considered by the UN and the World Health Organization to be suitable, improved sanitation facilities in warmer weather locales where water or sullage is readily available, but sewer pipes and plumbed in toilet facilities are not. Pour-flush latrines are advantageous as compared to ventilated pit latrines in that they can be fitted with a water seal or “trap” that prevents flying insects form entering the pit, thereby blocking transmission of pathogens. Moreover, the portal for a pourflush latrine can be sited at some distance from the leach pit, where the excreta is collected and decomposed, since the transport of the excreta to the leach pit is not wholly reliant on gravity. For example, the squatting plate can bear a waste portal which is connected to the leach pit via a pipe, and the excreta are pushed through the pipe by a water/sullage stream which has been poured into the portal by the user.
Pour-latrines require a low water volume (1-3 liters per “flush”), are suitable in cultures where anal cleansing traditions are prevalent, require minimum maintenance, can be sited in family residences and operated using sullage (as opposed to fresh water), effectively solving two problems (proper excreta and sullage disposal) with one device.
In most latrines, including pour-flush latrines, once the excreta is delivered to the leach pit, it is degraded by aerobic and anaerobic means, and will necessarily generate a variety of gases, many of which smell unpleasant, and some which are harmful to one's health. To prevent or ameliorate emission of sewage gases back into the squat hole room or living space where the waste portal is located, prior art pour-flush latrines have relied upon a variety of structural modifications: well-fitted squat hole covers, U-bend water seals (for example, a U-bend trap in a pipe connecting the squat hole and the leach pit) or use of squat pans having gooseneck-shaped pipe outlets, which discourage “back flow” of gases from the leach pit.
However, these solutions have a variety of disadvantages. Squat hole covers are only effective if replaced diligently and if the tight seal between the squat hole perimeter and the cover can be maintained, which is difficult in a non-climate controlled environments. U-bend pipe water seals and gooseneck shaped pipe outlets frequently and regularly become blocked by the bulky anal cleansing materials (cardboard, grasses, leaves, maize cobs, vegetable peels, cement bags, rags, etc.) utilized in the absence of Western-style toilet paper, resulting in sewage backup or a reversion to non-sanitized waste disposal methods. They also require a larger volume of water to completely flush excreta to the pit.
A typical 3 inch (7.6 centimeter) diameter plastic U-bend fitting has an internal volume approaching one liter. When waste is deposited in the U-bend, several liters of water can be required to completely flush it to the pit. Although water may be located nearby the latrine, the inconvenience of carrying large quantities can deter users from operating the latrine to the full extent of its hygienic potential.
Thus, there remains a need in the art for latrines and latrine pans that can be inexpensively produced and distributed, that reduce the potential for pathogen transmission through flying insects, reduce or prevent backflow of sewage gases, require minimal water for flushing, and are easy to maintain and use.

BRIEF SUMMARY OF THE INVENTION

The invention described herein includes a pour-flush latrine pan mountable at a surface that includes a collection basin and a flapper. The collection basin has an upper bowl portion that tapers to an outlet extending through a wall of the collection basin at its lower end. The flapper includes a counterbalance device and a coverplate disposed on opposite sides of a pivot. The coverplate has a shape adapted to cover the outlet of the collection basin when the coverplate is engaged against the lower end of the collection basin. The flapper is pivotally mounted against the collection basin such that the coverplate engages against the lower end of the collection basin when a pivotal force attributable to the counterbalance device is greater than a pivotal force applied to the coverplate that engages the lower end of the collection basin. In an embodiment, the shape of the coverplate defines a channel that engages the lower end of the collection basin about its perimeter when the coverplate is engaged against the lower end of the collection basin
The invention also includes latrine pan assemblies, latrines and methods that employ the latrine pan.
Also included within the scope of the invention are pour-flush latrines and latrine pan assemblies for installation into a pour-flush latrine that include the above described latrine pan and water dispensing vessel.
Methods of preventing or reducing a flow of a sewage gas from a leach pit, methods of reducing the incidence of adverse health effects caused by sewage gas exposure in a latrine-using individual and methods of sustainably and hygienically removing human excreta from human contact are also included within the scope of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description of embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which may be preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

FIG. 1, which includes FIGS. 1A and 1B, is a perspective view of the pour-flush latrine pan of the invention, in the “closed” and the “open” position respectively;

FIG. 2, which includes FIGS. 2A and 2B, is a side view of the pour-flush latrine of the invention, in the “closed” and the “open” position respectively;

FIG. 3, which includes FIGS. 3A and 3B, is a top plan view of the pour-flush latrine of the invention, in the “closed” and the “open” position respectively;

FIG. 4, which includes FIGS. 4A and 4B, is a bottom plan view of the pour-flush latrine of the invention, in the “closed” and the “open” position respectively;

FIG. 5, which includes FIGS. 5A and 5B, is a front view of the pour-flush latrine of the invention, in the “closed” and the “open” position respectively;

FIG. 6, which includes FIGS. 6A and 6B, is a back view of the pour-flush latrine of the invention, in the “closed” and the “open” position respectively;

FIG. 7 is an embodiment of a flapper to be used with the latrine pan of the invention;

FIG. 8 is a detail view of the lower end of the basin and the coverplate of the latrine pan of the invention;

FIG. 9 is a detail side view of the latrine pan of the invention;

FIG. 10 is a detail view of the interior of the lower end of the basin when the coverplate is engaged against the lower end;

FIG. 11 illustrates component parts of the latrine pan assembly of the invention;

FIG. 12, including FIGS. 12A, 12B and 12C, shows a cross section of the latrine pan of the invention in the serial steps of an open/close cycle of the flapper;

FIG. 13 includes FIGS. 13A and 13B. FIG. 13A is a top plan view of the latrine of the invention installed in a cement slab FIG. 13B illustrates a cross section of the latrine pan and slab installment taken at X-X₁of FIG. 13A;

FIG. 14 is a schematic representation of a closed pit latrine of the invention shown in cross section; and

FIG. 15 is a schematic of representation of a pour-flush latrine of the invention shown in cross section, wherein the latrine pan is remotely located from the leach pit.

DETAILED DESCRIPTION OF THE INVENTION

The invention described herein includes a pour-flush latrine pan that can be mass produced and transported to remote areas at relatively low cost, is resistant to blockage under everyday use when installed as part of a latrine, prevents flying insects from passing in and out of the pit, and prevents or reduces the backflow of sewage gases from the leach pit into the squatting room or residence in which the pour-flush latrine is sited. Also contemplated within the scope of the invention are pour-flush latrine pans and assemblies, pour-flush latrines, methods of reducing the incidence of adverse health effects, methods of preventing or ameliorating the flow of sewage gases, such as hydrogen sulfide or ammonia, from a leach pit, methods of installing the pour flush latrine pan, and methods of sustainably and hygienically removing human excreta from human contact. Each aspect of the invention is described in detail below.
The invention in some embodiments will be described with reference to the drawings provided herein. In the specification, words such as “inner” and “outer,” “upper” and “lower,” “superior” and “inferior,” “distal” and “proximal”, “inwardly” and “outwardly,” and “uppermost” and “lowermost,” and words of similar import are used for assisting in the understanding of the invention when referring to the drawings and absent a specific definition or meaning otherwise given by the specification for such terms, should not be considered limiting to the scope of the invention.
The invention includes a pour-flush latrine pan that includes a collection basin and a flapper. The collection basin may be of any size, design or shape known or to be developed in the art. For example, the collection basin design may be circular, oval, square, kidney-shaped or triangular when regarded in plan view. As will be understood in the art, numerous “squat pan” designs have been developed based upon cultural and habitual preferences and any of these designs may be employed in the present invention. Regardless of the specific shape, it may be preferred that the design/shape of the collection basin be adapted to reducing urine splashing, facilitate flushing of excreta and sanitary products with minimal water flow, permit assumption of a comfortable collection position by adults, and/or be on a scale that can be safely used by children.
Depending on the social or cultural preferences in the locale in which the latrine pan is to be used, the collection basin may be formed as a toilet stool (i.e., a structure that facilitates defecation while sitting) or a squat pan (i.e., a structure used in areas where the preference is to defecate while squatting).
In an embodiment, the collection basin is formed as a squat pan and includes a bowl having a radially extending elongated portion, such that the collection basin's top plan view resembles a stylized pear-shape (see, e.g. FIG. 3A). In this embodiment, it may be preferred that the elongated portion extends from the upper bowl portion only, so that the collection basin has a non-uniform depth, with the bowl of the basin through which the outlet extends, being the deeper.
It may be preferred that the collection basin has a capacity of about 3 to about 15 liters, to ensure safe and spill-less receipt of human waste and of the flush water. In an embodiment, it may be preferred that the collection basin has a length dimension of about 9 inches (23 centimeters) to about 22 inches (56 centimeters) and, independently, the width dimension may be about 6 inches (15 centimeters) to about 16 inches (41 centimeters). Smaller sizes within this range would be desirable for application where primary use by children is foreseeable, such as in schools.
The collection basin may be manufactured as an integral piece or it may be manufactured in components (of the same or of different materials) that are subsequently assembled. The collection basin may be cast, molded, thermoformed, stamped, carved or otherwise formed, depending on the material selected. Any material known or to be developed in the art may be used, such as, without limitation, a polymer, a plastic, a composite, a metal, a concrete, a cement, a natural or synthetic stone, a composite, a wood, a fiberglass, a marble, a porcelain, a ceramic, gravel, and a clay. It is preferred that the material selected is durable, resistant to crazing, and smooth surfaced.
The collection basin may be formed of a first material, and then coated with one or more of a second material to realize desirable surface properties. For example, the collection basin may be made of a fiberglass material that is coated with a non-stick polymer (for example polytetrafluoroethylene (TEFLON®)) to increase the ability to maintain a clean, excreta-free surface or an antibacterial coating, such as nanoparticles of titanium dioxide, silver, copper, gold, and/or gallium.
In some embodiments, the material of the collection basin is a thermoplastic or thermoset polymer or copolymer as such materials are durable, relatively inexpensive and easy to fabricate and to clean. Suitable plastics may include polyethylene terephthalate, high-density polyethylene, polyvinyl chloride, low-density polyethylene, polypropylene, polystyrene, polyvinylidene chloride, high impact polystyrene, polyamides, acrylonitrile butadiene styrene, polyethylene/acrylonitrile butadiene styrene, polycarbonate, polycarbonate/acrylonitrile butadiene styrene, polyurethanes, melamine formaldehyde, phenolics, polyetheretherketone, polyetherimide, polymethyl methacrylate, polytetrafluoroethylene, and/or urea-formaldehyde.
Regardless of the shape or size selected, the collection basin includes a bowl, an upper portion of which having walls that taper downwardly to an outlet. The outlet extends through a wall of the basin, preferably a wall in the lower end of the basin. The slope of the taper may be steep or gradual, depending on the design and shape of the overall collection basin. Preferably, as noted above, the slope is adjusted to minimize splashing from the sidewalls and to facilitate progress of excreta and other waste through the outlet.
The outlet may be, for example, a simple hole defined by the lowermost sidewall of the basin or a conduit defined by the narrowing of the basin sidewalls of the lower end of the basin. In some embodiments, the outlet is defined by a structure that is adapted to be fitted to pipe or conduit, so that the latrine pan and the leach pit may be sited apart but remain in fluid communication. In an embodiment, the outlet has a diameter of about 10 cm to about 20 cm, although outlets of any dimension may be used. However, the most suitable dimension is one large enough to permit egress of the non-standard toilet paper substitutes used in the region where the latrine is to be installed but not so large that it poses a danger to small children.
The pour-flush latrine pan of the invention also includes a flapper. The flapper itself includes a counterbalance device and a coverplate that are disposed on opposite sides of a pivot relative to one another. As noted with the collection basin, the flapper can be manufactured as one piece or as several pieces that are subsequently assembled together. The flapper or its component parts may be made of any of the materials discussed above as suitable for the collection basin, including coatings and additional surface treatments.
The coverplate is adapted to cover the outlet of the collection basin when the coverplate is engaged against the lower end of the collection basin. If the outlet has a substantially circular cross section, it may be preferred that the coverplate is disc shaped, or modified-disc shaped (that is, discs with radial extensions, flanges, lips, etc.) and is of a diameter that is at least slightly greater than the diameter of the outlet, so that when the coverplate is engaged against the lower end of the collection basin the outlet is fully covered.
To provide a liquid seal that prevents, reduces or ameliorates the passage of sewage gases and flying insects from one side of the cover plate (e.g., the side in communication with the leach pit) to the other side (e.g., the side in communication with the environment of the squatting room), it may be preferred that the coverplate has a shape that engages and folds upwardly around a lower end of the collection basin, thereby forming a receptacle or channel for collecting a portion of flush water. The flush water that remains on the cover plate after closure of the flapper creates an airtight liquid seal between the collection basin and the coverplate of the lapper.
The reliability of the seal can be improved by ensuring that any remaining flush water is directed towards the interface of the outlet of the collection basin and the flapper. Thus, it is preferred to form a channel around the perimeter of the coverplate. The channel may engage the entire perimeter of the lower end, or only a portion of the perimeter of the lower end.
Additionally, in an embodiment, the coverplate may contain a convex portion that extends within the outlet of the collection basin when the coverplate is engaged against the lower end of the collection basin. The convex portion reduces the depth of water collected in the coverplate, thereby reducing upward splashing of water during use. The convex portion also facilities proper alignment/re-alignment of the channel and the lower end of the basin after an open/close cycle of the flapper. In some embodiment, the rise of the convex portion may serve as a wall of the channel.
Under everyday use of the pour-flush latrine pan, several milliliters of flush liquid will remain residing in the channel after flushing, forming a liquid seal between the surface of the coverplate and the lower end of the basin. The seal serves to prevent, reduce and/or ameliorate the backflow of gases from the leach pit into the environment of the residence or squatting room. Such reduction may be at least by 50%, by 80% or by 90% or more as compared to an uncovered leach pit. Advantageously, the seal may also prevent entry of most types of insects into the human environment or into the leach pit, blocking a major transmission route for diarrheal diseases.
In an embodiment of the invention, the channel is designed to capture and retain a minimal amount of liquid—enough to create a functional seal, but not enough to give rise to excessive splashing during use, and not enough to require use of an extremely large counterweight which would place unnecessary stress on the hinge of the flapper. In an embodiment, it may be desired that the channel is designed to contain about 5 mls to about 200 mls. It may be preferred that the amount of water present is about 125 mls.
When using the latrine pan, the flapper is pivotally mounted against the collection basin. The coverplate and a counterbalance device are disposed on opposite sides of the pivot. The coverplate is placed so that it covers the outlet, as described above, and on the other side of the pivot is located the counterbalance device. The flapper “teeter totters” between a closed state (where the coverplate is engaged against the lower end of the basin) and an open state (where the coverplate and the lower end disengaged and spaced apart to permit egress of excreta and other waste into the leach pit). Whether the flapper is in an “open” or a “closed” state depends on which end of the flapper is exerting the greater pivotal force.
Specifically, the counterbalance device serves to maintain the closed state of the flapper by exerting a pivotal force that is greater than any counter pivotal force applied to the coverplate either: (1) when the coverplate is vacant (and/or contains water for the water seal) or (2) when the coverplate bears excreta or other waste. The counterbalance device must have a mass that exerts a pivotal force that is greater than or equal to the pivotal force exerted by an average excreta quantity, but not greater than the force exerted by a hand poured water stream. As will be appreciated in the art, such mass will vary depending on the location of the pivot relative to the counterbalance device, but any such adjustments are well within the purview of a person of ordinary skill in the art and/or common sense.
In an embodiment, the pivot is substantially equidistant between the coverplate and the counterbalance device, and the center of mass of the counterbalance device or the coverplate is about 5 to about 20 centimeters from the pivot.
In a simple iteration, the counterbalance device may be any material of sufficient mass or weight (“weight material”) secured to the flapper, either during manufacture or post-manufacture. For example, the counterbalance device may be a rock, brick or block of suitable sized or mass found on site as the latrine is constructed that is affixed to the flapper.
In an embodiment, the counterbalance device is a container (either integral with or affixed to) the flapper, that can be filled with a weight material. This affords the advantage of eliminating unnecessary weight to the latrine pan while it is in transit to the remote location where the latrine is to be built. As latrine construction almost always utilizes cast concrete for one application or another, as in for example, the formation of the floor or slab that holds the latrine pan/collection basin, it is particularly advantageous and convenient to use concrete as the counterweight material.
In such embodiment, it may be preferred that the container is selected from a cube, a rectangular prism, a sphere or a similar shape. In an embodiment, the container is a cup shape or a hollow cylinder that is filled with a weight material chosen from, without limitation, cement, concrete, asphalt, sand, water, stones, pebbles, metal, particulates, wood and mixtures thereof. It may be a closed container or an open container. When using concrete or another material that sets or cures to form a solid body, it may be advantageous to form one or more outward protrusions extending from the walls of the container. These protrusions may serve to mechanically lock the section of cured concrete within the cup, yet can be formed from injection molded plastic without locking the part onto the tool. In an embodiment, the protrusions extend about 1 mm from the interior sidewalls of the container.
It some embodiments, it may also be preferred that that the legend CONCRETE is molded into the container. The English word “concrete” is recognized and understood in many countries, even those where English may not be routinely written or spoken. Alternatively, one can print or tape the legend CONCRETE on the container.
As noted above, the amount of weight material will vary depending on the amount of pivotal force that the counterbalance device must exert. The volumetric dimensions of the container will necessarily vary depending on the amount or type of weight material that is required in a specific latrine application. It may be preferred that the container has volumetric dimensions (that is, be of a size) to contain an amount of weight material sufficient to exert a pivotal force upon the flapper that is greater than a pivotal force exerted on the flapper by an average excreta quantity when the average excreta quantity rests and/or makes impact with the coverplate when delivered by gravity from a point about 40 to about 70 centimeters from the surface of the coverplate. By “average excreta quantity” it is meant about one average bowel movement from a reasonably healthy individual suffering from no significant gastrointestinal disorders.
In an embodiment, the container may have volumetric dimensions to contain an amount of weight material sufficient to exert a pivotal force that is greater than a pivotal force exerted by about 0.5 to about 3 average excreta quantities when the average excreta quantities rest and/or makes impact the coverplate. When the counterweight exerts a pivotal force that is less than the weight of the excreta deposited in the flapper, the flapper will automatically open to allow the excreta to fall into the latrine pit. If the counterweight exerts a pivotal force that is greater than the weight of the excreta deposited in the flapper, the act of pouring flush water should apply sufficient force on the flapper to move it to the open position and empty the collection basin.
As a non-limiting example, the amount of weight material may range from about 50 grams to about 1500 grams, more specifically, about 60 grams, about 85 grams, about 100 grams, about 130 grams, about 250 grams, about 500 grams, about 750 grams, about 1000 grams, about 1300 grams and about 1500 grams.
The flapper is pivotally mounted against the collection basin so that the coverplate engages against the lower end of the basin. The flapper may be pivotally mounted directly to the basin (for example, to its exterior), or it may be mounted on a nearby structure (such as a wall or post). The pivot may take the form of any known or to be developed in the art. For example, without limitation, the pivot may be an arrangement of aligned holes in the flapper and the basin and pins; the flapper may include a loop through which a baton is inserted, allowing for pivotal rotation; the pivot may be a flexible bracket on the underside of the basin through which the flapper is threaded, or the pivot may be a fulcrum inserted beneath the flapper.
A non-limiting embodiment of the latrine pan and the latrine pan assembly included in the invention is illustrated in FIGS. 1 to 13. With reference to these Figures, a pour-flush latrine pan 100 that includes a collection basin 102 and a flapper 104 is shown. The collection basin 102 includes an upper bowl portion 108 having an upper edge 154, which includes a flange 140 that encircles the perimeter of the upper edge 154. Upon installation of the pour-flush latrine pan 100 into a cement apron or slab 170, the flange 140 is substantially co-planar with the surface 160 of the slab 170. In these illustrative Figures, the flange 140 is shown as extending around the entire perimeter; in practice the flange may extend for only a portion or several discontinuous portions of the perimeter or be wholly absent.
The bowl 107 of the collection basin 102 includes an upper bowl portion 108 that includes an interior wall 120 that tapers downwardly to an outlet 112 that extends through the basin's wall at a lower end 116 of the collection basin 102.
The pour-flush latrine pan 100 further includes a flapper 104 that in turn includes a coverplate 106 and a counterbalance device 118 that are disposed on opposite sides of a pivot 122. In the embodiment shown in the Figures, the flapper 104 is pivotally mounted to the exterior 152 of the collection basin 102. The pivot 122 is an aligned holes-and-pin configuration; a first set of holes 147, 147′ (not shown) extends through an extension body 146 of the flapper 104, and a second set of holes 148, 148′ (not shown) are present in a spaced bracket 150, 150′ on the exterior 152 of the collection basin 102.
In the closed state, the flapper 104 causes the coverplate 106 to engage against the lower end 116 of the collection basin 102 covering the outlet 112. The outlet 112 has a circular cross section; thus the coverplate 106 is substantially disk shaped so as to be adapted to cover the outlet 112 when the coverplate 106 is engaged against the lower end 116 of the collection basin 102. The coverplate 106 includes a centered convex portion 136, a circumferential rim 138, and a lip 168. The circumferential rim 138 extends above the lower end 116 of the collection basin 102 basin when the flapper 104 is in the closed position and serves to hold a portion of flush water within the coverplate and create an airtight seal.
A channel 104 is also included in the coverplate 106. During use, the channel 104 assures that a quantity of the residual pour-flush liquid is directed to the perimeter of the coverplate to form a liquid seal 128 between the coverplate 106 and the lower end 116 of the collection basin 102.
The flapper 104 also includes a counterbalance device 118 that is illustrated as a hollow cup or cylinder 162. It can be filled with a weight material 161 that is cement as the latrine pan is prepared for site installation.
The latrine assemblies that may be provided to latrine builders or householders include the latrine pans described herein, as well as a water dispensing vessel, and other optional article, including communication or written materials. In the embodiment illustrated in FIG. 11, the assembly includes a spouted water dispensing vessel 174 and a communication device 172 that is written installation instructions.
A latrine of the invention employing the latrine pan as describe herein can be sited in a public structure, such a marketplace public facility, a family residence or may be situated outside a family residence is a separate superstructure (a so-called “outhouse”). Preferred dimensions of the room or structure are about 800 mm by about 1000 mm or greater. The latrine may be configured by locating the latrine pan immediately above a leach pit. The structure and design of leach pits are well established in the art and will vary depending topographical, cultural, and environmental conditions. Such adjustments are well within the skill set of a person of ordinary skill in the art and will not be repeated herein.
FIG. 14 shows a schematic of a covered pit latrine 188 of the invention in cross section. The pour-flush latrine pan 100 is situated in a cement slab 170 and enclosed in a latrine shelter 176. The outlet (not visible) of the latrine pan 100 is in communication with the leach pit 126 (equipped with an optional vent pipe 190) when the flapper 104 is in an open state. The user 186 is shown in squat position, using the footbed 182 (one shown only, as is cross section) to orient his hind area 184 over the outlet. A spouted water dispensing vessel 174 containing flush sullage is at the ready.
Alternatively, a latrine of the invention can be sited at a distance from the leach pit but remain in fluid connection with the leach pit. A schematic of this arrangement is shown in FIG. 15. The latrine 188′ includes a latrine structure 176′, which houses the latrine pan 100. The latrine pan 100 is in communication with a junction box 192 of sufficient volume to permit the flapper to toggle between open and closed states. The a junction box 192 is connected to a pipe 180, which empties into a leach pit 126′. Depending on the size of the footprint available, the latrine pan can be placed about 1 to about 5 meters from the leach pit and connected to the leach pit via pipeworks or a junction box laid to a correct grade (preferably about 1 in 30). The leach pit is preferably sealed with the exception of at least one vent, which is sited preferably as far from the latrine pan as is feasible. The junction box can be formed of any suitable material, including or not limited to concrete, brick, plastic, metal, clay, glass, etc.
In any latrine configuration an optional latrine pan cover may be provided to cover the latrine pan when not in use.
Preferably, the latrine pan is fitted into a cavity that is substantially the same size and shape as the latrine pan, so that the basin (with the exception of the outlet which should remain unobstructed) is structurally reinforced. Such reinforcement extends the structural life of the latrine pan and prevents accidental falls into the leach pit in the event that an individual loses balance and makes bodily contact with the latrine pan. As an example, the cavity may be formed in the earth (when the outlet is connected via pipeworks to a remotely sited leach pit) or in a cement slab. A cement slab can be preferably cast around the latrine pan to ensure intimate contact between the surfaces and strong bonding of the pan to the slab.
During the installation of the latrine pan and the building of the latrine, it is preferred that the latrine pan is cast into a cement slab of about 2 inches to about 6 inches (5.1 centimeters to 15.2 centimeters) in thickness. The slab should be reinforced with metallic wire to increase its strength and longevity. It is also possible to secure the latrine pan in a cavity formed in a cement slab which also serves to seal the leach pit, such that an upper edge of the collection basin is substantially flush with the surface of the slab. To accommodate such arrangement, the upper bowl portion may include a flange that extends from the uppermost edged of the upper bowl portion. As shown in FIG. 13, when fitted in a cement slab 170, the topmost surface 110 of the flange 140 is substantially coplanar with the surface of the slab. Alternatively, this flange can be positioned below the surface if concrete is to be cast directly around the pan. This assures that the pan will be well bound to the concrete. It is preferred that the cement slab has (or is covered with a flooring material that has) a smooth surface that permits free draining. In an embodiment, the slab is constructed so as to slope towards the latrine pan to permit draining of any split flushing water.
In an embodiment of the latrine, the backmost edge of the latrine pan is located at least about 100 mm to about 150 mm from any wall or structure. Footbeds may be placed on either side of the latrine pan for user guidance, to ensure that the excreta is delivered as near as possible to the outlet.
Once installed, the latrine can be easily operated and maintained. To use the latrine, the user squats over the collection basin of the latrine pan, first removing the latrine pan cover, if one was present. Since the latrine pan is initially empty except for the small amount of water that creates the water seal, the latrine pan is in the closed position. Preferably in the collection position, the user delivers the excreta, which is conveyed by gravity to the surface of the coverplate. The latrine remains in a closed position despite the added weight of the excreta on the coverplate. Ideally, a single purpose water dispensing vessel is maintained in an area near the latrine pan, and contains about 1 liter to about 3 liters of water. The water may be non-potable water, such as unpurified river water, sullage or grey water.
Using the water dispensing vessel, the user then “pour-flushes” the latrine—he pours the water into the latrine pan; the force applied by the water increases the pivotal force exerted upon the coverplate, exceeding the pivotal force that is (counter)exerted by the counterbalance device, and cover plate is disengage from the lower edge of the outlet and is spaced apart from the outlet to permit egress of the excreta. Once the excreta have been removed from the coverplate, the flapper returns to closed position. In most instances, sufficient liquid residue should remain in the pan to create the liquid seal. In the event that additional liquid is necessary or the liquid acting as a seal evaporates under hot weather conditions, an additional aliquot of liquid can be applied to restore it.
During the pour-flush process, the flapper 104 is toggled between the “closed” and the “open” position using balanced/unbalanced pivotal force. Referencing FIGS. 12A, 12B and 12C, which shows a cross section of the latrine pan, the pivotal force F₁exerted by the counterbalance device 118 exceeds both the pivotal force F₂exerted by the empty coverplate 106 a and the pivotal force F₃attributable to a coverplate 106 a upon which rests an average excreta quantity 166. The flapper 104 remains therefore in the closed position. When a water stream 130 is applied to the coverplate 106, the pivotal force F₄attributable to the water stream (alone or combined with F₃) exceeds F₁and the flapper transitions to the open state disengaging from the coverplate, allowing the average excreta quantity 166 to pass from the coverplate 106 a.
The water dispensing vessel used to apply the water stream that flushes the latrine pan may be any known or to be developed in the art. It may include a bucket, a scoop, a ladle, a pail, a spout-bearing vessel, a hose, and an expandable bladder. In some embodiments, one may prefer that the water dispensing vessel is sized to dispense only a pre-determined amount of water, to conserve water and to avoid over-flow of the leach pit. For example the water dispensing vessel may be chosen from those that have liquid volume capacity selected from about 1 liter, about 1.5 liters, about 2 liters and about 3-5 liters. A spouted water dispensing vessel may be preferred.
In practice, the pour-flush latrine pan described herein may be assembled with a water dispensing vessel, and optionally, written or digital materials and distributed as a latrine pan assembly for installation into a pour-flush latrine. The written or digital materials may include a communication device that provides at least one of (a) instructions for assembly of the pour-flush latrine pan, (b) instructions for installation of the pour-flush latrine pan, (c) instructions for use of the pour-flush latrine pan assembly, and (d) instructions for maintenance of the pour-flush latrine pan assembly. Such information may be presented in a language and cultural style suitable for the area in which the assemblies are to be distributed.
It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A pour-flush latrine pan mountable at a surface comprising a collection basin and a flapper,

the collection basin having an upper bowl portion tapering to an outlet extending through a wall of the collection basin at a lower end of the collection basin,

the flapper comprising a counterbalance device and a coverplate disposed on opposite sides of a pivot,

the coverplate having a shape adapted to cover the outlet of the collection basin when the coverplate is engaged against the lower end of the collection basin,

the flapper being pivotally mounted against the collection basin such that the coverplate engages against the lower end of the collection basin when a pivotal force attributable to the counterbalance device is greater than a pivotal force applied to the coverplate that engages the lower end of the collection basin.

2. The pour-flush latrine pan of claim 1, wherein the shape of the coverplate defines a channel that engages the lower end of the collection basin about at least a portion of its perimeter when the coverplate is engaged against the lower end of the collection basin.

3. The pour-flush latrine pan of claim 1, wherein the shape of the coverplate defines a channel that engages the lower end of the collection basin about its entire perimeter when then coverplate is engaged against the lower end of the collection basin.

4. The pour-flush latrine pan of claim 3, wherein the shape of the coverplate includes a convex portion that extends within the outlet of the collection basin when the coverplate is engaged against the lower end of the collection basin.

5. The pour-flush latrine pan of claim 4, wherein the channel contains a liquid that forms a liquid seal between a first surface of the cover plate and the lower end of the collection basin that prevents or reduces a flow of a sewage gas from a second side of the coverplate to the first side of the coverplate.

6. The pour-flush latrine pan of claim 5, wherein the sewage gas is hydrogen sulfide or ammonia.

7. The pour-flush latrine pan of claim 1, wherein the counterbalance device comprises a container that is filled with a weight material.

8. The pour-flush latrine pan of claim 7, wherein the container has a volumetric dimension that can contain an amount of weight material sufficient to exert a pivotal force upon the flapper that is greater than a pivotal force exerted on the flapper by an average excreta quantity when the average excreta quantity rests upon the coverplate.

9. The pour-flush latrine pan of claim 8, wherein the amount of weight material is selected from about 60 grams, about 85 grams, about 100 grams, about 250 grams, about 500 grams, about 750 grams, about 1000 grams, about 1300 grams and about 1500 grams, and the weight material is cement.

10. The pour-flush latrine pan of claim 8, wherein the container is a hollow cylinder and the weight material is selected from cement, concrete, asphalt, sand, water, stones, pebbles, metal, particulates, and wood.

11. The pour-flush latrine pan of claim 1, wherein the coverplate includes a circumferential rim that extends above the lower end of the collection basin about at least a portion of its perimeter when then coverplate is engaged against the lower end of the collection basin.

12. The pour-flush latrine pan of claim 1, wherein the coverplate includes a circumferential rim that extends above the lower end of the collection basin about its entire perimeter when then coverplate is engaged against the lower end of the collection basin.

13. The pour-flush latrine pan of claim 1, comprising a flange extending around the perimeter of the upper bowl portion.

14. The pour-flush latrine pan of claim 1, wherein the upper bowl portion includes an elongated portion extending radially therefrom.

15. The pour-flush latrine pan of claim 14, wherein the entirety of the interior of the bowl portion tapers downwardly toward the outlet.

16. The pour-flush latrine pan of claim 1, wherein the flapper is pivotally mounted to the exterior of the collection basin.

17. The pour-flush latrine pan of claim 1, wherein the pivot of the flapper is a pair of pins extending laterally away from an extension body of the flapper, the counterbalance device and coverplate being mounted on opposite ends of the flapper body, the pins engaging a pair of aligned holes on a pair of spaced brackets on the exterior of the collection basin.

18. The pour-flush latrine pan of claim 1, wherein the pivot of the flapper is at least one hole extending laterally through an elongate body of the flapper, the counterbalance device and coverplate being mounted on opposite ends of the flapper body, each hole engaging a pin extending from the exterior of the collection basin.

19. The pour-flush latrine pan of claim 1, wherein the pivot of the flapper is at least one hole extending laterally through an extension body of the flapper, the counterbalance device and coverplate being mounted on opposite ends of the flapper body, each hole engaging a pin that also engages a pair of aligned holes on a pair of spaced brackets on the exterior of the collection basin.

20. The pour-flush latrine pan of claim 1, installed in a slab such that the upper edge of the upper bowl portion is substantially flush with a surface of the slab.

21. The pour-flush latrine pan of claim 1, wherein the collection basin is manufactured of a material selected from a polymer, a plastic, a composite, a metal, a concrete, a cement, a natural or synthetic stone, a composite, a wood, a fiberglass, a porcelain, a ceramic, gravel, and a clay.

22. The pour-flush latrine pan of claim 1, wherein the flapper is manufactured of a material selected from polymer, a plastic, a composite, a metal, a concrete, a cement, a natural or synthetic stone, a composite, a wood, a fiberglass, a porcelain, a ceramic, gravel, and a clay.

23. A pour-flush latrine pan assembly for installation into a pour-flush latrine comprising the latrine pan of claim 1 and a water dispensing vessel.

24. The assembly of claim 23 wherein the water dispensing vessel is selected from a bucket, a pail, a spout-bearing vessel, a hose, and an expandable bladder.

25. The assembly of claim 23, wherein the water dispensing vessel has a liquid capacity selected from about 1 liter, about 1.5 liters, about 2 liters and about 3-5 liters.

26. The assembly of claim 24, further comprising written materials.

27. The pour-flush latrine pan assembly of claim 26, wherein the written materials comprise a communication device that provides at least one of (a) instructions for assembly of the pour-flush latrine pan, (b) instructions for installation of the pour-flush latrine pan, (c) instructions for use of the pour-flush latrine pan assembly, and (d) instructions for maintenance of the pour-flush latrine pan assembly.

28. The pour-flush latrine pan assembly of claim 27, wherein the communication device comprises text, a drawing, and a cartoon.

29. A method of preventing or reducing a flow of a sewage gas from a leach pit comprising installing in a slab the pour-flush latrine pan of claim 1.

30. The method of claim 29, wherein the flow of the sewage gas is reduced by at least 50% as compared to a conventional open leach pit.

31. The method of claim 30, wherein the sewage gas is hydrogen sulfide or ammonia.

32. A method of reducing the incidence of adverse health effects caused by sewage gas exposure in a latrine-using individual comprising installing over a leach pit the pour-flush latrine pan of claim 1.

33. The method of claim 32, wherein the adverse health effect is chosen from mucus membrane irritation, sore throat, cough, shortness of breath, respiratory ailments, fluid accumulation in the lungs, fatigue, pneumonia, loss of appetite, headaches, irritability, poor memory, dizziness, loss of consciousness and death.

34. A method of installing a pour-flush latrine comprising fitting the pour-flush latrine pan of claim 1 in fluid communication with a leach pit.

35. The method of claim 34, wherein the outlet of the collection basin and the leach pit are separated by at least one meter.

36. The method of claim 34, wherein the pour-flush latrine pan is fitted into a cement slab.

37. The method of claim 34, wherein the cement slab contains a footbed on either side of the collection basin to facilitate delivery of a bowel movement as near as possible to the outlet of the basin.

38. A pour-flush latrine comprising a leach pit in fluid communication with the latrine pan of claim 1.

39. The latrine of claim 38, sited in a public sanitation facility.

40. The latrine of claim 38, sited in a family residence.

41. A method of sustainably and hygienically removing human excreta from human contact comprising

providing a latrine of claim 38;

delivering to the coverplate of the latrine pan a bowel movement of a user, wherein the bowel movement rest upon a first surface of the coverplate;

applying to the bowel movement-bearing coverplate a water stream such that the pivotal force exerted on the coverplate exceeds the pivotal force exerted on the counterbalance device causing the coverplate to become disengaged from the lower end of the basin such that the coverplate and the lower end are spaced apart sufficiently and the bowel movement is released from the surface of the cover plate, descending downwardly towards the leach pit;

wherein upon release of the bowel movement, the coverplate re-engages against the lower end of the collection basin and a liquid seal is formed between the first surface of the coverplate and the lower end of the collection basin.

42. The method of claim 41, wherein the water stream is applied by manually pouring water into the collection basin using a water dispensing vessel.