FIELD OF THE INVENTION

The invention disclosed herein relates to sanitaryware. More particularly, it relates to a water trap used in or with sanitaryware, such as toilets, basins, baths, and the like.

BACKGROUND TO THE INVENTION

Water is crucial to sustaining life, yet a scarce natural resource in large parts of the world such as sub-Saharan Africa where water is scarce not because of drought, but because the communities lack reliable water supplies. These communities make use of traditional flushing toilets, which typically use more than 6 litres of water per flush.

There have been improvements in the past to reduce water usage of conventional flushing toilets. Improvements include implementing two jets of water to create a double vortex to clear the toilet pan quicker. This design also has a subsurface inlet to clear the water trap. The design requires a pump and still uses about 5 litres of water.

A second design uses a 45-degree outlet with a reduced diameter pipe along with a flushing mechanism similar to that of a conventional flushing mechanism where water is discharged from the rim of the pan. The design can use about 2 litres of water per flush.

What these known toilet designs have in common is a reduction in the volume of water per flush.

Sanitaryware, including toilets, basins, baths, and the like are provided with a water trap. The water trap is a generally U-shaped bend provided below or near a bottom part of the relevant piece of sanitaryware. Such water traps are also commonly referred to as U-bends. Another common term used for such a water trap in the application of the toilet is the term “P-trap” (where the trap has a horizontal outlet) and “S-trap” (where the trap has a vertical outlet), since the combination of the water trap and the straight piece of drainage pipe connected thereto resembles the letter “P” turned 90°.

The U-shape of the water trap is shaped such to maintain a water seal for the prevention of odours entering the toilet from the sewer. The water seal is governed by the depth of the water in the bend, which is determined by the vertical height of the invert of the outlet in relation to the soffit of the lowest part of the U-shaped bend. The U-trap, therefore, forms a bend which turns from a generally downwards direction to a generally upwards direction.

The purpose of the water trap is to create a water seal between the relevant piece of sanitaryware and the sewer on the other side thereof, thereby preventing noxious gasses from the sewage line from entering a building through the piece of sanitaryware.

For basins, baths, etc. the water trap may be provided by an additional piece or additional pieces of plumbing. Although a flushing force is not typically required to clear the water trap as large solids are not typically disposed of in basins or sinks. The gravitation force of the liquid in the basin or sink is generally sufficient to clear the water trap. However, it is not uncommon for some pieces of solid waste, such as food debris, etc. to be disposed of through a sink or basin.

In toilets, the water trap is typically integrally formed with the pan of the toilet, located between the bowl of the toilet, and the outlet of the toilet where it connects to the sewer. A problem that may occur in sanitaryware using reduced volumes of water for flushing, is that the volume of water may not be sufficient to clear the waste and replenish the water seal, or may not have the required energy to push solid waste over the bend of the water trap. This may lead to blockage, or to unsanitary conditions.

The Applicant considers that the design of the water trap can be improved.

The preceding discussion of the background to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was part of the common general knowledge in the art as at the priority date of the application.

SUMMARY OF THE INVENTION

In accordance with an aspect of the invention there is provided a toilet pan comprising a bowl that is in fluid communication with an outlet of the toilet pan through a water trap, the water trap having a generally U-shaped flow path, wherein at least a partial length of the water trap has an ovalshaped inner cross-section, and wherein a major axis of the oval-shaped inner cross-section taken at one or more cross-sections along the at least partial length having the oval-shaped inner cross-section has a non-vertical orientation.

The major axis of the oval-shaped inner cross-section may transition from having a substantially vertical orientation to a non-vertical orientation, and wherein the oval-shaped cross-section with the substantially vertical orientation may be further from the outlet that the cross-section with the non-vertical orientation.

At least a section of the at least partial length having the oval-shaped inner cross-section may have a gradual twist such that a major axis of the oval-shaped cross-section may rotate along the flow path of the twisted section.

The major axis of the oval-shaped cross-section may rotate between about 30° and about 180° along the twisted section, more preferably between about 45° and 110°, and most preferably about 90°.

The twisted section may start proximate a lowermost part of the water trap and may extend towards the outlet.

The oval-shaped cross-section proximate the lowermost part of the water trap may be substantially egg-shaped, with the narrower end thereof operatively pointing downwards.

In accordance with a further aspect of the invention there is provided a water trap having an inlet that is in fluid communication with an outlet of the water trap, the water trap having a generally U- shaped flow path, wherein at least a partial length of the water trap has an oval-shaped inner cross-section, and wherein a major axis of the oval-shaped inner cross-section taken at one or more cross-sections along the at least partial length having the oval-shaped inner cross-section has a non-vertical orientation.

The major axis of the oval-shaped inner cross-section may transition from having a substantially vertical orientation to a non-vertical orientation, and wherein the oval-shaped cross-section with the substantially vertical orientation may be further from the outlet than the cross-section with the non-vertical orientation.

At least a section of the at least partial length having the oval-shaped inner cross-section may have a gradual twist such that the major axis of the oval-shaped cross-section may rotate along the flow path of the twisted section.

The major axis of the oval-shaped cross-section may rotate between about 30° and about 180° along the twisted section, more preferably between about 45° and 110°, and most preferably about 90°. The twisted section may start proximate a lowermost part of the water trap and may extend towards an outlet of the water trap.

In some embodiments, the oval-shaped cross-section proximate the lowermost part of the water trap may be substantially egg-shaped, with the narrower end thereof operatively pointing downwards.

These features may provide a higher centre of gravity at the lowest point in the U-trap and a lower centre of gravity of the cross-section as the cross-section moves past the U-shaped bend to the outlet. It may also provide an increased water height in the water trap for the same volume of water (compared to a round inner cross-section). This may minimise the vertical movement of the flushed material as it moves along the flow path of the water trap, thereby reducing the energy required to remove waste from the trap. This, in turn, may result in a reduced loss of potential energy and maximise the kinetic energy and thus the velocity (and momentum) of the flushed material, following the conservation of energy principle. This may enable the flushed material, particularly solids, to clear the water trap despite using a smaller volume of water for flushing.

This oval shaped water trap may also reduce the total volume of water required to provide the water seal. The reduced volume in the trap may therefore reduce the volume of water required to clear and replenish the trap.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

Figure 1 is a front view of a toilet pan;

Figure 2 is a right side view of the toilet pan of Figure 1 ;

Figure 3 is a right side view of the toilet pan of Figure 1 indicating cross-section lines

A-A to F-F;

Figures 4-9 are cross-sectional views as taken along cross-section lines A-A to F-F, respectively; Figure 10 is a front view of a water trap;

Figure 11 is a three-dimensional view of the water trap of Figure 10;

Figure 12 is a right side view of the water trap of Figure 10; and

Figure 13 is a right side view of the water trap of Figure 10 indicating cross-sectional lines A-A to F-F.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

Embodiments of a water trap and sanitaryware incorporating such a water trap are disclosed below. The sanitaryware may be a toilet or, more specifically, a toilet pan. Typically, a toilet pan consists of a bowl that is in fluid communication with an outlet of the toilet pan, which is in use connected to a conveyance system such as a sewer pipe, or directly to an on-site disposal system. A water trap connects the bowl with the outlet and provides a flow path for flushing material, such as liquids and solids, from the bowl through the outlet. The water trap may have a generally U- shaped flow path in which the water level may be above the maximum internal height of the lowermost part of the water trap’s outlet. The water trap having such a U-shaped profile results in the lowermost part thereof being filled with water, thereby creating a water seal which prevents noxious gasses from escaping the sewer through the bowl. It will be understood by a person skilled in the art that the lowermost part of the water trap will be the bottom of the U-shaped flow path.

The water trap may be used with various sanitaryware such as basins, sinks, showers, and the like. The aforementioned sanitaryware should be understood as being non-limiting examples and do not constitute an exhaustive list. The sanitaryware is in fluid communication with an outlet that, in use, connects to a downstream sewer or conveyance system. A water trap for a basin may connect the basin bowl to the outlet and provide a flow path for disposing of liquid and small solids. This water trap may be visible to the user and may ease maintenance thereof. A water trap for a shower may connect the drain of the shower to the outlet and provide a flow path for disposing of liquid material and small solids. This water trap will likely not be visible to the user and may be underneath the shower floor.

At least a partial length of the water trap may have an oval-shaped inner cross-section. An ovalshaped inner cross-section may have a smaller area compared to the area of a circular inner cross-section with the same diameter as the length of a major axis of the oval-shaped inner crosssection. The major axis of the oval-shaped inner cross-section taken at one or more crosssections along the at least partial length may have a non-vertical orientation, i.e. any transverse angle or horizontal. The oval-shaped inner cross-section may therefore require a smaller water volume to create the water seal and to flush liquid and solids towards the downstream conveyance or treatment system.

When referring herein to orientations of cross-sections, e.g. axes of a cross-section, it should be understood to be considered as from the relative perspective of an observer looking at the crosssection in the same general direction of the flow in the flow path. In other words, the direction perpendicular to the cross-section.

In some embodiments, the major axis of the oval-shaped inner cross-section may transition from having a substantially vertical orientation to a non-vertical orientation as one moves along the flow path towards the outlet. For example, as cross-sections (or slices) are taken along the flow path, initial cross-sections (closer to the bowl) may have a substantially vertical orientation. That is to say that the major axis of the oval-shaped inner cross-section may have a substantial vertical orientation. At subsequent cross-sections, moving closer to the outlet, the orientation of the major axis may gradually transition from substantially vertical to non-vertical, and even to horizontal.

In other embodiments, at least a section of the at length having the oval-shaped inner crosssection may have a gradual twist such that the major axis of the oval-shaped inner cross-section may rotate along the flow path of the twisted section. The twisted section may start proximate the lowermost part of the water trap in some embodiments. “Proximate” for the purpose of this invention means that the twisted section should start exactly at, immediately after or immediately before the bottom of the U-shaped flow path. The exact length of what constitutes “proximate” depends on the absolute dimensions of the relevant embodiment. In toilet pans, “proximate” would typically be within 2-3cm along the flow path from the bottom thereof.

When referring to an oval shape of a cross-section of the water trap in accordance with this invention, it should be understood to imply the wider interpretation of including both ellipses (i.e. with two axes of symmetry), as well as an egg shape (i.e. with only one axis of symmetry), unless explicitly stated otherwise or if the context indicates otherwise. The term “about”, when used with an angular quantity expressed in degrees, indicates a tolerance of plus or minus 10 degrees.

Embodiments of the invention will now be described with reference to the accompanying drawings, by way of example only. Figures 1 to 3 show an embodiment of a toilet pan (100) including a toilet bowl (1 10), an outlet (120) and a water trap (130). The water trap (130) forms a fluid connection between the toilet bowl (1 10) and the outlet (120). The water trap (130) has a generally U-shaped flow path in which, in use, the water level is above the maximum internal height of a lowermost part (132) of the water trap (130), which is indicated by dotted line (2-2).

In this embodiment (100) the water trap (130) forms an integral part of the toilet pan (100). The lowest point of the outlet, indicated by dotted line (1 -1 ) is higher than the highest point (2-2) of the lowermost part, i.e. the bend (132), of the water trap (130). This creates a water seal to prevent noxious gasses from escaping from the sewer through the toilet pan (100). Line 1 -1 illustrates the lowest water height in the water trap at rest, i.e., when not flushing and with the water seal replenished.

A partial length of the water trap (130) has an oval-shaped inner cross-section. The length of the water trap (130) with an oval inner cross-section spans over part of the front (134) and rear (136) sections, including the lowermost part (132) of the water trap (130). In other embodiments, the length of the water trap (130) with an oval inner cross-section may span over the entire flow path. The shape of the oval inner cross-section may change along the flow path. In certain areas, the oval inner cross-section may be more elliptical, whereas in other areas the oval inner crosssection may be more egg-shaped.

A section of the length with the oval-shaped inner cross-section has a gradual twist such that a major axis (140) thereof rotates along the flow path of a twisted section (160). This gradual twist and rotation of the major axis (140) is illustrated more clearly in the section views of Figures 4 to 8. The twisted section (160) starts proximate the lowermost part (132) of the water trap (130) and extends towards the outlet (120). The gradual twist of the oval-shaped inner cross-section (162) terminates proximate to the end (138) of the rear section (136), i.e. proximate the outlet (120). The major axis (140) of the oval-shaped cross-section (162) rotates about 90° between the start and end of the twisted section (160). In other embodiments, the major axis (140) of the ovalshaped cross-section (162) may rotate between about 30° and about 180° along the twisted section (160), more preferably between about 45° and 110°.

Figures 4 to 9 show the cross-sections (A-A to F-F) along the flow path of the water trap (130). Figure 9 is a cross-section (F-F) immediately after the end of the twisted section (160) and transitions into a round cross-section (F-F) at the outlet (120) so as to enable the outlet to be connected to a standard sewer pipe. Figures 4 to 8 correspond to the oval cross sections (A-A to E-E) indicated on Figure 3. The major axis (140) of the oval-shaped inner cross-section (A-A to E-E) is perpendicular to and longer than a minor axis (142) thereof. As shown in Figures 5 and 6, some of the oval-shaped inner cross-sections (B-B and C-C) are substantially egg-shaped and symmetrical about the major axis (140). These substantially egg-shaped cross-sections (B-B and C-C) are wider near a top section (154) thereof, with the narrower end (156) operatively pointing downwards, before the gradual twist in the flow path begins. These substantially egg-shaped cross-sections (B-B, C-C) in combination with the twisted section (160) reduces the vertical movement that the flushed material is required to make so as to clear the water trap (136) as it moves along the flow path of the water trap (136).

Rotation of the oval-shaped inner cross-section (C-C to E-E) results in an increased water height in the water trap for the same volume of water (compared to a round inner cross-section). This minimises the vertical movement required of the flushed material to clear the water trap (160) as it moves along the flow path of the water trap (130). This, in turn, results in a reduced loss of potential energy and maximises the kinetic energy and thus the velocity (and momentum) of the flushed material, following the conservation of energy principle. This enables the flushed material, particularly solids, to clear the water trap (130) despite using a smaller volume of water for flushing.

Figures 10 to 13 show a water trap (200) in accordance with the invention. The water trap (200) is a separate component that may be used with sanitaryware such as a basin, in contrast with the integrally-formed water trap of the toilet pan (100) described above.

The water trap (200) is substantially similar to the water trap (130) which forms an integral part of the toilet pan (100) as described above. As alluded to above, the difference being that the water trap (200) may be used with other forms of sanitaryware such as a basin, showers and sinks, and the like. In the interest of brevity, the features of this discrete component water trap (200) that correspond to features of the integrally formed water trap in the toilet pan (100) above are not described in detail again. Such corresponding features are indicated with similar reference numerals, however, starting with a leading “2” whereas like features in the water trap of the toilet pan (100) above start with a leading “1 ”. For example, the lowermost parts of the toilet pan (100) and the water trap (200) are indicated with reference numerals (132) and (232), respectively.

The cross-section lines (A-A to F-F) shown on Figure 13 correspond to the cross-sections shown in Figures 4 to 9, respectively.

The invention disclosed therefore provides a toilet pan in which the combination of an oval cross- section and a twisting section thereof reduces the volume of water required in addition to reducing the vertical movement that flushed material is required to make so as to clear the integrally formed water trap thereof as it moves along the flow path of the water trap. It further provides a discrete component water trap having the same features. These features may reduce the volume of water that is required to flush or drain waste, thereby saving water.

The foregoing description has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure.

The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

Finally, throughout the specification and accompanying claims, unless the context requires otherwise, the word ‘comprise’ or variations such as ‘comprises’ or ‘comprising’ will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.