Water-washable toilet
The innovative design of the drain trap pipe in flush toilets, featuring an inverted triangular to square cross-section transition, addresses the inefficiencies in wash-down toilets by ensuring effective waste discharge and reduced energy loss.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOTO LTD
- Filing Date
- 2024-11-29
- Publication Date
- 2026-07-24
AI Technical Summary
Existing flush toilets, particularly wash-down type toilets, face challenges in effectively discharging waste due to the limitations of swirling flows, which weaken the pushing force of flushing water, leading to difficulties in passing waste through the drain trap pipe.
The design incorporates a drain trap pipe with a descending pipe and an ascending pipe, where the ascending pipe's cross-section is shaped as an inverted triangle at the lowest point, transitioning to a square shape over a predetermined length, and a horizontal, straight base at the highest point, ensuring smooth flow conversion and reduced energy loss.
This configuration enhances the discharge efficiency of flushing water and waste, minimizing clogging and energy loss, while maintaining a high discharge rate and rapid waste removal.
Smart Images
Figure 0007894559000001 
Figure 0007894559000002 
Figure 0007894559000003
Abstract
Description
Technical Field
[0001] The present invention relates to a flushing toilet, and particularly to a flushing type flushing toilet having a trap pipeline including a descending pipeline and an ascending pipeline.
Background Art
[0002] In a flushing toilet, a drainage trap pipeline including a descending pipeline and an ascending pipeline is connected to a bowl part, and the dirt discharged into the bowl part is discharged by washing water. Regarding the shape of the flow path cross-section, which is a cross-section orthogonal to the central axis of this drainage trap pipeline, various shapes are adopted. For example, in the flushing toilet of Patent Document 1, the flow path cross-section at the inlet part of the drainage trap pipeline is substantially triangular, the flow path cross-section at the lowest point is substantially rectangular, and the flow path cross-section at the entrance of the ascending pipeline is a shape combining an arc and a straight line. With such a shape, floating dirt is surely discharged.
[0003] Furthermore, in the flushing toilet of Patent Document 2, the flow path cross-section of the drainage trap pipeline is formed in a shape combining an arc and a straight line, or a substantially rectangular shape, and with such a shape, dirt and paper are less likely to get clogged.
[0004] Also, in the flushing toilet of Patent Document 3, the flow path cross-section of the drainage trap pipeline is formed in a shape combining an arc and a straight line, or a substantially rectangular shape, and with such a shape, the discharge performance of dirt and washing water is improved.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Patent Document 2
Patent Document 3
Summary of the Invention
[0006] On the other hand, there is a demand for flush toilets that can achieve a combination of features, such as a quick start to waste discharge (initial action), improved flow within the drain trap pipe, and a faster waste discharge rate.
[0007] In particular, in washdown type flush toilets, since the siphon action effectively does not draw in the flushing water from the bowl, the flushing water and waste must be discharged over the drain trap pipe solely by the pushing force of the flushing water flowing into the bowl.
[0008] In addition, in flush toilets that use a swirling flow of flushing water discharged from the spout to clean the bowl, it is not possible to set a high instantaneous flow rate of flushing water discharged from the spout, and the instantaneous flow rate must be kept relatively low. As a result, the force pushing the flushing water into the bowl is weakened, making it more difficult for the flushing water and waste to pass through the drain trap pipe.
[0009] Therefore, the present invention aims to provide a flush toilet that can effectively discharge flushing water and waste, even in a wash-down type toilet that cleans the bowl portion with a swirling flow. [Means for solving the problem]
[0010] To achieve the above objective, the present invention provides a flush toilet of the washdown type, comprising: a bowl portion for receiving waste; a discharge portion for discharging flushing water into the bowl portion to form a swirling flow; a drain trap pipe comprising a descending pipe connected to the bowl portion and extending downward from the bowl portion, and an ascending pipe connected to the descending pipe and extending upward from the descending pipe, wherein the ascending pipe extends from the lowest point of the drain trap pipe to the highest point that defines the water level in the bowl portion, and the flow path cross-section of the ascending pipe is formed in a substantially inverted triangular shape at the lowest point, and the flow path cross-section is formed in a substantially square shape over a predetermined length, and the base of the flow path cross-section at the highest point is substantially horizontal and substantially straight.
[0011] With the present invention configured in this way, since the flow channel cross-section at the lowest point of the rising pipe is formed in a substantially inverted triangular shape, the flow vector from the descending pipe to the rising pipe can be smoothly converted, and the cleaning water can flow into the rising pipe without losing much of the energy of the flow pushed from the bowl into the descending pipe. Furthermore, since the flow channel cross-section is formed in a substantially square shape over a predetermined length of the rising pipe, the cleaning water flowing upward within the rising pipe can be straightened, reducing energy loss and increasing the discharge rate of waste. Moreover, since the base of the flow channel cross-section at the highest point is formed in a substantially horizontal, substantially straight shape, a wide flow channel can be secured at the highest point, allowing a large amount of cleaning water and waste to pass over the highest point with less energy. Through these actions, cleaning water and waste can be effectively discharged.
[0012] In the present invention, preferably, the riser conduit has a substantially straight central axis in a predetermined section in which the flow path cross-section is substantially rectangular. According to the present invention configured in this way, since the central axis in a predetermined section of the flow path cross-section which is substantially rectangular is formed to be substantially straight, clogging of waste in the riser pipeline can be suppressed.
[0013] In the present invention, preferably, the ascending pipeline has an increasing flow path cross-sectional area in at least a portion thereof, from the lowest point to the highest point. According to the present invention configured in this manner, since the cross-sectional area of the flow path of the rising pipeline increases from the lowest point to the highest point, the flow velocity of the cleaning water flowing through the rising pipeline can be reduced, and energy loss of the cleaning water flow can be suppressed.
[0014] In the present invention, preferably, the riser conduit has a substantially constant maximum height and maximum width in its flow channel cross-section. According to the present invention configured in this manner, since the maximum height and maximum width of the flow channel cross-section of the riser pipeline are formed to be substantially constant, energy loss of the flow of cleaning water flowing through the riser pipeline can be suppressed.
[0015] In the present invention, preferably, the ascending pipeline has a substantially rectangular cross-section of the flow path including the highest point. According to the present invention configured in this way, since the flow path cross-section including the highest point is substantially rectangular in shape, the portion of the flow path cross-section that is substantially rectangular over a predetermined length and the flow path cross-section at the highest point, which is substantially straight with a substantially horizontal base, can be smoothly connected, thereby suppressing turbulence in the flow of the washing water.
[0016] In the present invention, preferably, the rising pipeline is provided with a curved section extending from the lowest point over a predetermined distance, and in this curved section, the cross-sectional shape of the flow path of the rising pipeline gradually changes from a roughly inverted triangular shape at the lowest point to a roughly square shape. According to the present invention configured in this way, in the curved section, the cross-sectional shape of the flow path of the rising pipeline gradually changes from a roughly inverted triangular shape at the lowest point to a roughly square shape. Therefore, flow resistance when transitioning from a roughly inverted triangular flow path cross-section to a roughly square flow path cross-section can be suppressed, and washing water and waste can be effectively discharged. [Effects of the Invention]
[0017] According to the flush toilet of the present invention, even in a wash-down type toilet that cleans the bowl area with a swirling flow, the flushing water and waste can be effectively discharged. [Brief explanation of the drawing]
[0018] [Figure 1] It is a plan view showing a flushing toilet according to an embodiment of the present invention. [Figure 2] It is a sectional view taken along line II-II of FIG. 1. [Figure 3] It is an enlarged sectional view showing a drain trap pipe of the flushing toilet according to an embodiment of the present invention. [Figure 4] It is a sectional view taken along line IV-IV of FIG. 3. [Figure 5] It is a sectional view taken along line V-V of FIG. 3. [Figure 6] It is a sectional view taken along line VI-VI of FIG. 3. [Figure 7] It is a sectional view taken along line VII-VII of FIG. 3. [Figure 8] It is a sectional view taken along line VIII-VIII of FIG. 3. [Figure 9] It is a sectional view taken along line IX-IX of FIG. 3. [Figure 10] It is a sectional view taken along line X-X of FIG. 3. [Figure 11] It is a diagram schematically showing a cross-sectional shape of an inlet portion of an ascending pipe of a drain trap pipe of a flushing toilet according to an embodiment of the present invention. [Figure 12] It is a sectional view showing a superposition of cross-sections of an inlet portion and an outlet portion of a descending pipe. [Figure 13] It is a sectional view showing a superposition of each cross-section from an inlet portion of an ascending pipe to an upper cross-section. [Figure 14] It is a comparison diagram showing a comparison of a trap pipe of a flushing toilet according to an embodiment of the present invention and trap pipes of Comparative Examples 1 and 2. [Figure 15] [[ID=4 Next, a flush toilet according to an embodiment of the present invention will be described with reference to Figures 1 to 7. First, the basic structure of the flush toilet according to an embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a plan view showing a flush toilet according to an embodiment of the present invention, and Figure 2 is a cross-sectional view taken along the line II-II in Figure 1.
[0020] As shown in Figures 1 and 2, reference numeral 1 denotes a flush toilet according to an embodiment of the present invention. This flush toilet 1 is a wash-down type toilet that uses the flow of water caused by the difference in water level in the bowl to wash away waste. It comprises a toilet body 2 and a water storage tank 4 that stores the water used to wash the toilet body 2. The toilet body 2 is made of ceramic with a glazed layer formed on its surface, with a skirt portion 6 formed at the bottom and a bowl portion 8 formed in the front of the upper half. A common water passage 10 is formed at the upper rear of the bowl portion 8, with its upstream end communicating with the water storage tank 4. Furthermore, a drain trap pipe 12 for discharging waste is formed at the lower rear of the bowl portion 8.
[0021] The aforementioned water storage tank 4 is the water source for flushing, and a drain valve 14 is provided inside this water storage tank 4, which can be opened and closed by an operating lever (not shown). This embodiment can also be applied to direct-pressure flush toilets that do not have a water storage tank 4 and are supplied with flushing water directly from the water supply, or to flush toilets of the type that are supplied with flushing water by a flush valve.
[0022] The bowl portion 8 comprises a bowl-shaped waste receiving surface 16, a rim portion 18 located at the upper edge, and a recess 20 formed below the waste receiving surface 16. Here, the inner circumferential surface 18a of the rim portion 18 has an overhanging shape toward the inside, so that the swirling washing water, as will be described later, does not splash out to the outside.
[0023] A first water outlet 22, which discharges cleaning water, is formed on the inner circumferential surface of the rim portion 18 of the bowl portion 8, slightly behind the center on the left side when viewed from the front. A second water outlet 24, which discharges water, is formed on the right rear side (downstream side) when viewed from the front. These first water outlets 22 and the second water outlets 24 are configured to form a swirling flow that rotates in the same direction (counterclockwise in Figure 1).
[0024] Furthermore, the common water passage 10 formed at the rear upper part of the flush toilet 1 described above branches into a first water passage 26 and a second water passage 28 toward the front of the toilet. The first water passage 26 is for supplying flushing water to the first outlet 22, and the second water passage 28 is for supplying flushing water to the second outlet 24. In this embodiment, the first water passage including the first water outlet and the second water passage including the second water outlet may be formed by a distributor or the like, which is separate from the toilet bowl body.
[0025] Here, the first outlet 22 and the second outlet 24 discharge cleaning water along the inner circumferential surface 18a of the overhanging rim portion 18, and the inner wall surface of the bowl portion 8 is cleaned as the cleaning water swirls along the inner circumferential surface 18a and flows down little by little. At this time, the instantaneous flow rate of the cleaning water discharged from each outlet is suppressed so that the cleaning water discharged from the first outlet 22 and the second outlet 24 does not overflow the rim portion 18 and splash out of the bowl portion 8.
[0026] Next, as shown in Figure 2, the drain trap pipe 12 includes a descending pipe 32 that connects to the lower part 20a of the recess 20, which is part of the recess 20 of the bowl portion 8, and extends downward and rearward, and an ascending pipe 34 that connects to the descending pipe 32 and extends upward. Furthermore, the ascending pipe 34 is connected to a downstream drain pipe 36, which is connected to a drain socket (not shown) and drains waste into a drain opening provided in the floor or wall.
[0027] The descending pipe 32 is connected to the lower part 20a of the recess 20 and has an inlet 38 where the flow switches from the lower part 20a of the recess 20 to the descending pipe 32. In this embodiment, the inlet 38 of the descending pipe 32 is defined as the point where the rate of change in the cross-sectional area of the connection between the lower part 20a of the recess 20 and the descending pipe 32 becomes small or zero. However, the position of the inlet 38 varies slightly depending on the shape of the connection between the lower part 20a of the recess 20 and the descending pipe 32. Furthermore, the descending pipe 32 is connected to the inlet 40 of the ascending pipe 34 at the lowest point B of the drain trap pipe 12.
[0028] The descending pipe 32 descends from its inlet 38 to the inlet 40 of the ascending pipe 34. The inlet 38 of the descending pipe 32 and the inlet 40 of the ascending pipe 34 are each provided as flow path cross-sections perpendicular to the central axis X of the drain trap pipe. The inlet 40 is located at the lowest point B of the drain trap pipe 12. Before cleaning, at least a portion of the recess 20 and the drain trap pipe 12 are filled with accumulated water, forming a water seal. In order to form a water seal of a certain amount or more, in this embodiment the highest point T of the drain trap pipe 12 is positioned higher than the inlet 38 of the descending pipe 32, so that the descending pipe 32 and a portion of the recess 20 connected to the descending pipe 32 can be filled with water to form a water seal. In other words, the water level of the accumulated water in the bowl portion 8 is determined by the height of the highest point T.
[0029] Next, the ascending pipeline 34 is a pipeline connected to the downstream side of the descending pipeline 32 at the lowest point B, and extends from the lowest point B to the highest point T. Furthermore, as will be described later, the flow path cross-section of the ascending pipeline 34 is formed in a substantially inverted triangular shape at the lowest point B, and in a predetermined section the flow path cross-section is formed in a substantially rectangular shape. In addition, the ascending pipeline 34 is provided with a curved section extending from the lowest point B to a predetermined section, and in this curved section the shape of the flow path cross-section gradually changes from an inverted triangular shape to a substantially rectangular shape. Furthermore, the base of the flow path cross-section at the highest point T is formed in a substantially horizontal, substantially straight shape. In this embodiment, the ascending pipeline 34 is formed such that the predetermined section in which the flow path cross-section is formed in a substantially rectangular shape includes the highest point T.
[0030] Furthermore, a relatively wide space 35 is provided downstream of the riser pipe 34, above the highest point T, and the flushing water and waste flowing out of the riser pipe 34 flows through this space 35 into the drain pipe 36. That is, when flushing the toilet, the water and waste in the bowl 8 are pushed away by the flushing water flowing into the bowl 8, overflow the highest point T of the riser pipe 34, enter the space 35, and fall into the drain pipe 36. Here, the cross-sectional area of the flow path formed by the space 35 is sufficiently wider than the cross-sectional area of the flow path of the riser pipe 34, so even when the flushing water and waste overflow the highest point T, the space 35 is not substantially filled with water. Also, the cross-sectional area of the flow path of the drain pipe 36 provided downstream of the space 35 is sufficiently wider than the cross-sectional area of the flow path of the riser pipe 34, so the drain pipe 36 is not substantially filled with water either. Therefore, in this embodiment of the flush toilet 1, a siphon effect does not substantially occur.
[0031] Next, the cross-sectional shapes of the descending pipe 32 and the ascending pipe 34 will be explained with reference to Figures 3 to 9. Figure 3 is an enlarged cross-sectional view of the drain trap pipe of the toilet bowl body. Figure 4 is a cross-sectional view along the line IV-IV in Figure 3 (cross-sectional view of the inlet of the descending pipe), and Figure 5 is a cross-sectional view along the line V-V in Figure 3 (cross-sectional view of the inlet of the ascending pipe). Figure 6 is a cross-sectional view along the line VI-VI in Figure 3 (first cross-sectional view of the ascending pipe), Figure 7 is a cross-sectional view along the line VII-VII in Figure 3 (second cross-sectional view of the ascending pipe), Figure 8 is a cross-sectional view along the line VIII-VIII in Figure 3 (third cross-sectional view of the ascending pipe), Figure 9 is a cross-sectional view along the line IX-IX in Figure 3 (upper cross-sectional view of the ascending pipe), and Figure 10 is a cross-sectional view along the line X-X in Figure 3 (cross-sectional view of the outlet of the ascending pipe). Furthermore, the cross-sections of the descending pipe 32 and ascending pipe 34 shown in Figures 4 to 10 all correspond to "flow channel cross-sections" cut in a direction perpendicular to the central axis of the drain trap pipe 12.
[0032] First, as shown in Figure 4, the cross-sectional shape of the inlet 38 of the descending pipe 32 is approximately rectangular. The cross-section of the inlet 38 comprises an upper side 38a, a right side 38b, a lower side 38c, and a left side 38d. Here, the lower side 38c is arc-shaped, and the upper side 38a is longer in the lateral direction than the lower side 38c. In addition, the right side 38b and the left side 38d are gently inclined inward and are arranged symmetrically with respect to the line connecting the highest point of the upper side 38a and the lowest point of the lower side 38c.
[0033] Next, as shown in Figure 5, the cross-sectional shape of the inlet 40 of the rising pipe 34 (corresponding to the outlet of the descending pipe 32) is approximately an inverted triangle. The cross-section of the inlet 40 has an upper side 40a, a right side 40b, and a left side 40c. Here, strictly speaking, the right side 40b and the left side 40c are formed in the shape of a circular arc with a relatively large radius of curvature, but the cross-section of the inlet 40 as a whole can be said to be approximately an inverted triangle. Furthermore, the point where the right side 40b and the left side 40c intersect in the cross-section of the inlet 40 corresponds to the lowest point B of the drain trap pipe 12. Note that the cross-section of the inlet 40 is provided so as to be symmetrical with respect to the vertical axis passing through the lowest point B. Thus, in this embodiment, since the flow path cross-section at the lowest point B of the rising pipe 34 is formed in an approximately inverted triangle shape, the flow vector from the descending pipe 32 to the rising pipe 34 can be smoothly transformed. This allows the cleaning water to flow into the rising pipe 34 without significantly losing the energy of the flow pushed from the bowl section 8 into the descending pipe 32.
[0034] Although not shown in the illustration, the cross-sectional shape of the descending pipe 32 gradually changes from a roughly rectangular shape to a roughly inverted triangle from its inlet 38 towards the inlet 40 of the ascending pipe 34 (corresponding to the outlet of the descending pipe 32). In particular, the outlet side 32a of the descending pipe 32 (Figure 2), when the inlet 38 is set to 0 and the inlet 40 of the ascending pipe 34 is set to 100, has a roughly inverted triangle cross-sectional shape as shown in Figure 5 in the range of 50 to 100 (or a shorter range including 100) of the descending pipe 32. By keeping the rate of change of the cross-sectional shape of the descending pipe 32 constant, energy loss caused by changes in the cross-sectional shape can be further suppressed. However, the rate of change can also be made non-uniform, as long as it is within a range where energy loss can be suppressed to some extent.
[0035] Next, as shown in Figure 6, the cross-sectional shape of the first cross-section 60 of the riser pipe 34, located slightly above the inlet 40 of the riser pipe 34, is approximately pentagonal. The first cross-section 60 comprises an upper side 60a, a right side 60b, a lower right side 60c, a left side 60d, and a lower left side 60e. Here, the right side 60b and the left side 60d are generally oriented vertically, while the lower right side 60c and the lower left side 60e are oriented diagonally and intersect in the center. Strictly speaking, each side has a radius (R), but the first cross-section 60 of the riser pipe 34 can be said to be approximately pentagonal as a whole. The first cross-section 60 is provided so as to be symmetrical with respect to the vertical axis passing through the intersection of the lower right side 60c and the lower left side 60e.
[0036] Next, as shown in Figure 7, the cross-sectional shape of the second cross-section 70 of the riser pipe 34, which is located slightly above the first cross-section 60, is approximately pentagonal. The second cross-section 70 comprises an upper side 70a, a right side 70b, a lower right side 70c, a left side 70d, and a lower left side 70e. Here, the right side 70b and the left side 70d are generally oriented vertically, while the lower right side 70c and the lower left side 70e are oriented diagonally and intersect in the center. Strictly speaking, a radius of curvature (R) is applied to the connection points of each side, but the second cross-section 70 of the riser pipe 34 can be said to be approximately pentagonal as a whole. Furthermore, the radius of curvature of the R applied to the connection points of each side of the second cross-section 70 is larger than that of the first cross-section 60. Note that the second cross-section 70 is provided so as to be symmetrical with respect to the vertical axis passing through the intersection of the lower right side 70c and the lower left side 70e.
[0037] Furthermore, as shown in Figure 8, the third cross-section 80 of the riser pipe 34, located slightly above the second cross-section 70, has a shape that combines a rectangle and an arc. The third cross-section 80 comprises an upper side 80a, a right side 80b, a left side 80c, and a lower side 80d. Here, the right side 80b and the left side 80c are generally oriented vertically, and the lower side 80d is a roughly arc-shaped convex shape directed downwards. That is, the radius of curvature of the R section that connected the right lower side 70c and the left lower side 70e in the second cross-section 70 is further increased in the third cross-section 80, forming a single arc-shaped lower side 80d.
[0038] Next, as shown in Figure 9, the upper cross-section 90 of the riser pipe 34 is approximately rectangular. The upper cross-section 90 of the riser pipe 34 has an upper side 90a, a right side 90b, a left side 90c, and a bottom side 90d, with the upper side 90a being slightly longer in the lateral direction than the bottom side 90d. The right side 90b and the left side 90c are gently inclined inward. Furthermore, the bottom side 90d can be seen as a convex arc shape with an extremely large radius of curvature, but it can be considered approximately straight. The cross-sectional shape of the riser pipe 34 is approximately the same as the cross-sectional shape shown in Figure 9, extending in a predetermined section 92 (Figure 3) that extends downstream from slightly above the third cross-section 80. In this embodiment, the central axis X of the drain trap pipe 12 in the predetermined section 92 is straight, and this predetermined section 92 extends to the vicinity of the outlet of the riser pipe 34. Thus, in this embodiment, since the central axis X in the predetermined section 92, which has a substantially rectangular cross-section, is formed to be substantially straight, clogging of waste in the riser pipe 34 can be suppressed. On the other hand, in the section from the cross-section 40 at the inlet of the riser pipe 34 to the predetermined section 92, the pipe is curved upward so that the direction of the riser pipe 34 is oriented upward. By changing the cross-section of this curved section, the effect of the upward curvature can be mitigated, and energy loss can be suppressed.
[0039] Furthermore, in this embodiment, the cross-sectional shape is also substantially rectangular on the downstream (upper) side of the predetermined section 92, and the cross-sectional shape 37 at the outlet of the riser pipe 34 shown in Figure 10 is also formed in a substantially rectangular shape that is substantially the same as the cross-sectional shape 90 at the top of the riser pipe 34. That is, the cross-sectional shape 37 at the outlet of the riser pipe 34 has an upper side 37a, a right side 37b, a left side 37c, and a bottom side 37d. Here, as shown in Figure 3, the cross-sectional shape 37 at the outlet of the riser pipe 34 includes the highest point T of the drain trap pipe 12. Therefore, the bottom side 37d of the outlet cross-sectional shape 37 is located at the height of the highest point T and is formed in a substantially horizontal, substantially straight shape. In this way, in this embodiment, since the bottom side 37d of the flow path cross-sectional shape 37 at the highest point T is formed in a substantially horizontal, substantially straight shape, a wide flow path can be secured at the highest point T, and a large amount of washing water and waste can pass over the highest point T with less energy.
[0040] As shown in Figures 5 to 10, the cross-sectional shape of the ascending pipe 34 is approximately an inverted triangle at the upstream inlet 40, maintaining continuity with the approximately inverted triangle of the outlet side 32a of the descending pipe 32 (Figure 5). The cross-section downstream gradually approaches an approximately square shape, as shown in Figures 6, 7, and 8. In other words, the flow path cross-sectional shape of the ascending pipe 34 gradually changes from an approximately inverted triangle at the lowest point B to an approximately square shape towards the downstream side. Thus, in this embodiment, since the flow path cross-sectional shape of the ascending pipe 34 gradually changes from an approximately inverted triangle at the lowest point B to an approximately square shape, flow resistance when transitioning from an approximately inverted triangle flow path cross-section to an approximately square flow path cross-section can be suppressed, and washing water and waste can be effectively discharged. Furthermore, in this embodiment, the cross-sectional shape of the ascending pipe 34 is approximately square for a predetermined section 92 of the ascending pipe 34 (Figure 3) and the entire downstream side thereof. As described above, in this embodiment, since the flow path cross-section is formed in a substantially rectangular shape over a predetermined length of the riser pipe 34, the washing water flowing upward within the riser pipe 34 can be straightened, reducing energy loss and increasing the rate of waste discharge. Preferably, the flow path cross-section is made substantially rectangular over a length of 40% to 60% of the total length of the riser pipe 34. Furthermore, it is preferable to provide the section with a substantially rectangular flow path cross-section in the range of 40% to 60% of the total length of the riser pipe 34 from the downstream end (highest point T) of the riser pipe 34.
[0041] Furthermore, as shown in Figures 4 to 10, in this embodiment, the maximum height H1 of the cross section perpendicular to the central axis X of the inlet 38 of the descending pipe 32, the maximum height H2 of the cross section perpendicular to the central axis X of the inlet 40 of the ascending pipe 34, the maximum height H3 of the first cross section perpendicular to the central axis X of the ascending pipe 34, the maximum height H4 of the second cross section perpendicular to the central axis X of the ascending pipe 34, the maximum height H5 of the third cross section perpendicular to the central axis X of the ascending pipe 34, the maximum height H6 of the upper cross section perpendicular to the central axis X of the ascending pipe 34, and the maximum height H7 of the outlet cross section perpendicular to the central axis X of the ascending pipe 34 are approximately constant. Therefore, the maximum height of the cross section perpendicular to the central axis X of the drain trap pipe 12 is approximately constant.
[0042] Furthermore, as shown in Figures 4 to 10, in this embodiment, the maximum width W2 of the cross section perpendicular to the central axis X of the inlet 40 of the riser pipe 34, the maximum width W3 of the first cross section perpendicular to the central axis X of the riser pipe 34, the maximum width W4 of the second cross section perpendicular to the central axis X of the riser pipe 34, the maximum width W5 of the third cross section perpendicular to the central axis X of the riser pipe 34, the maximum width W of the upper cross section perpendicular to the central axis X of the riser pipe 34, and the maximum width W7 of the outlet cross section perpendicular to the central axis X of the riser pipe 34 are substantially constant. Therefore, the maximum width W of the cross section perpendicular to the central axis X of the riser pipe 34 is substantially constant. In this way, in this embodiment, since the maximum height and maximum width of the flow path cross section of the riser pipe 34 are formed to be substantially constant, energy loss of the flow of cleaning water flowing through the riser pipe 34 can be suppressed. On the other hand, the maximum width W1 of the cross-section perpendicular to the central axis X of the inlet 38 of the descending pipeline 32 is narrower than the maximum width W2 of the cross-section perpendicular to the central axis X of the inlet 40 of the ascending pipeline 34.
[0043] Next, the cross-sectional shape of the inlet portion 40 of the riser pipe 34 will be described in detail with reference to Figure 11. Figure 11 is a schematic diagram showing the cross-sectional shape of the inlet portion of the riser pipe of the drain trap pipe of a flush toilet according to an embodiment of the present invention. As shown in Figure 11, the cross-sectional shape of the inlet 40 of the riser pipe 34 is approximately an inverted triangle, as described above. This approximately inverted triangular shape will be explained in detail. Figure 11 shows the shape of the inner wall of the inlet 40 of the riser pipe 34. The inlet 40 has an approximately triangular cross-sectional shape due to its upper side 42, right first side 44, right second side 46 connected to the right first side 44 by a connecting part 45, left first side 48, and left second side 50 connected to the left first side 48 by a connecting part 49. All of these sides, the upper side 42, right first side 44, right second side 46, left first side 48, and left second side 50, are approximately arc-shaped.
[0044] Furthermore, the center of the upper edge 42 of the inlet portion 40 of the riser pipe 34 is the upper end 51 of the cross-section, and the intersection of the right second side edge 46 and the left second side edge 50 is the lower end 52 of the cross-section. Here, in the cross-section of the inlet 40 of the riser pipe 34, the height (distance) b from the connection points 45 and 49 to the lower end 52 is greater than the height (distance) a from the upper end 51 to the connection points 45 and 49 (i.e., b > a). The cross-sectional shape of the inlet 40 is provided to be symmetrical with respect to the line connecting the upper end 51 and the lower end 52.
[0045] As shown in Figure 11, the cross-section of the inlet 40 of the riser pipe 34 is shaped such that the inward inclination angle β of the right second side 46 with respect to the vertical (specifically, the inclination of the tangent line drawn at the midpoint of the right second side 46 with respect to the vertical) is greater than the inward inclination angle α of the right first side 44 with respect to the vertical (specifically, the inclination of the tangent line drawn at the midpoint of the right first side 44 with respect to the vertical) (i.e., β > α). Similarly, the cross-section of the inlet 40 of the riser pipe 34 is shaped such that the inward inclination angle β of the left second side 50 with respect to the vertical (specifically, the inclination of the tangent line drawn at the midpoint of the left second side 50 with respect to the vertical) is greater than the inward inclination angle α of the left first side 48 with respect to the vertical (specifically, the inclination of the tangent line drawn at the midpoint of the left first side 48 with respect to the vertical) (i.e., β > α).
[0046] Furthermore, as shown in Figure 11, in the cross-section of the inlet 40 of the riser pipe 34, the angle γ formed by the tangent line drawn at the midpoint of the right second side 46 and the tangent line drawn at the midpoint of the left second side 50 is 105 degrees. Here, it is preferable that angle γ is between 85 degrees and 125 degrees. Angle γ is larger than the angles formed by the top side 42 and the left first side 48 and the right first side 44, respectively.
[0047] Next, Figure 12 will be used to explain the cross-sectional areas of the inlet 38 and outlet (corresponding to the inlet 40 of the ascending pipeline 34) of the descending pipeline 32. Figure 12 is a cross-sectional view showing the inlet and outlet cross-sections of the descending pipeline superimposed. As shown in Figure 12, the cross-sectional shape of the inlet 38 of the descending pipe 32 is shown by dashed lines, and the cross-sectional shape of the outlet is shown by solid lines. Here, the cross-sectional area S1 of the inlet 38 and the cross-sectional area S2 of the outlet are approximately the same. Therefore, since the height H1 of the cross-section of the inlet 38 and the height H2 of the outlet are approximately constant, the width W1 of the cross-section of the inlet 38 is made larger than the width W2 of the cross-section of the outlet (inlet 40 of the ascending pipe 34), thereby making the cross-sectional area approximately constant. Also, compared to the approximately rectangular inlet 38, the outlet (inlet 40 of the ascending pipe 34) is approximately an inverted triangle, so the base of the cross-section is narrower.
[0048] Next, the cross-sectional areas of each part of the riser pipeline 34 will be explained with reference to Figure 13. Figure 13 is a cross-sectional view showing the various cross-sections of the riser pipeline 34 superimposed from the inlet 40 to the upper cross-section 90. In Figure 13, the inlet 40 (Figure 5) is shown with a thick solid line, the first cross-section 60 (Figure 6) with a dashed line, the second cross-section 70 (Figure 7) with a dashed line, the third cross-section 80 (Figure 8) with a double dashed line, and the upper cross-section 90 (Figure 9) with a thin solid line.
[0049] As described above, the maximum heights H2 to H6 of each cross section from the inlet 40 to the upper cross section 90 of the riser pipe 34 are approximately constant, and the maximum widths W2 to W6 of each cross section are also approximately constant. Thus, while the maximum height and maximum width of each cross section of the riser pipe 34 are approximately constant, the cross-sectional shape gradually changes from the approximately inverted triangular shape of the inlet 40 to the approximately square shape of the upper cross section 90. Therefore, the cross section of the riser pipe 34 gradually expands from the approximately inverted triangular shape of the inlet 40 to the diagonally lower corners on both sides, and the flow path cross-sectional area of the riser pipe 34 increases from the lowest point B to the highest point T. Thus, in this embodiment, since the flow path cross-sectional area of the riser pipe 34 increases from the lowest point B to the highest point T, the flow velocity of the cleaning water flowing through the riser pipe 34 can be reduced, and energy loss of the cleaning water flow can be suppressed.
[0050] Furthermore, the cross-section of the riser pipe 34 is configured such that the flow path cross-sectional area widens in the lower part from the lowest point B to the highest point T, thus reducing the energy required to push up the waste with the washing water. In order to discharge waste from the riser pipe 34, it is necessary to push the waste up against gravity, but if the flow path cross-section is narrow in the lower part of the riser pipe 34, then in order to discharge the same amount of washing water and waste, it is necessary to push more washing water and waste upwards. This may increase the energy loss of the washing water flow. In contrast, in this embodiment, since the flow path cross-section in the lower part of the riser pipe 34 is wide, the amount of waste that needs to be pushed up to the top of the flow path cross-section is reduced, thus reducing energy loss.
[0051] Next, the three essential characteristics of a flush toilet—"speed of discharge initiation," "flow straightening in the descending pipe," and "discharge speed"—will be explained by comparing the flush toilet 1 according to this embodiment with the conventional flush toilets of Comparative Examples 1 and 2. Figure 14 is a comparison diagram showing the trap pipes of the flush toilet according to the embodiment of the present invention and the trap pipes of Comparative Examples 1 and 2. Figure 15 is a diagram showing the relationship between the residual waste percentage and time in the drain trap pipes of the flush toilet according to the embodiment of the present invention and the drain trap pipes of Comparative Examples 1 and 2. Figure 16 is a partially enlarged diagram of part A in Figure 15.
[0052] First, both Comparative Example 1 and Comparative Example 2 are conventional "wash-down toilets." In the flush toilet of Comparative Example 1, the cross-sectional shape perpendicular to the central axis at the inlet of the downward pipe is approximately square, the cross-sectional shape perpendicular to the central axis at the inlet of the upward pipe is approximately square, and the cross-sectional shape perpendicular to the central axis at the top of the upward pipe is approximately square. In the flush toilet of Comparative Example 2, the cross-sectional shape perpendicular to the central axis at the inlet of the downward pipe is approximately an inverted triangle, the cross-sectional shape perpendicular to the central axis at the inlet of the upward pipe is approximately a square, and the cross-sectional shape perpendicular to the central axis at the upper part of the upward pipe is approximately a square. In addition, in the flush toilet 1 according to this embodiment, as described above, the cross-sectional shape perpendicular to the central axis at the inlet of the descending pipe is approximately square, the cross-sectional shape perpendicular to the central axis at the inlet of the ascending pipe is approximately inverted triangle, and the cross-sectional shape perpendicular to the central axis at the upper part of the ascending pipe is approximately square.
[0053] To confirm the three characteristics of the flush toilets described above in Comparative Example 1, Comparative Example 2, and the embodiment, experiments were also conducted using simulated waste (using a large amount of fine particles with approximately the same mass as waste), and the results shown in Figures 15 and 16 were obtained. First, as shown in Figure 14, regarding the "speed of discharge initiation (initial action)," the flush toilets in Comparative Example 1 and the embodiment were faster (○), while Comparative Example 2 was slightly slower (△). Regarding the straightening of the flow in the descending pipe, the flush toilet according to Comparative Example 2 and the embodiment performed well (〇), while Comparative Example 1 performed poorly (△). Regarding the rate of waste discharge, the flush toilets in Comparative Example 1 and the embodiment were faster (○), while Comparative Example 2 was slightly slower (△).
[0054] Next, as shown in Figures 15 and 16, when waste is discharged from the bowl into the drain trap pipe, 100% of the waste is in the bowl at the start of discharge (0 seconds), and at the end of discharge, there is no waste remaining in the bowl (almost zero). Two seconds after the start of discharge, the waste in the bowl is discharged into the drain trap pipe due to the water flow caused by the drop in water level within the bowl. As shown in Figure 16, the flush toilet according to this embodiment, shown by the solid line, is the fastest to start discharging waste, followed by the flush toilet of Comparative Example 1, shown by the dashed line, and the flush toilet of Comparative Example 2, shown by the dashed line, is the slowest.
[0055] From the above, it was confirmed that the flush toilet according to this embodiment achieves all three characteristics necessary for a flush toilet: "speed of discharge initiation," "flow straightening in the descending pipe," and "discharge speed."
[0056] Next, the effects and advantages of the flush toilet according to the embodiment of the present invention described above will be explained. In the flush toilet according to the embodiment of the present invention, the cross-section at the lowest point B of the rising pipe 34 (the cross-section at the inlet 40 of the rising pipe 34) is formed in a substantially inverted triangular shape (Figure 5). This allows for a smooth conversion of the flow vector from the descending pipe 32 to the rising pipe 34, enabling flushing water to flow into the rising pipe 34 without significantly losing the energy of the flow pushed from the bowl 8 into the descending pipe 32. Furthermore, since the cross-section 90 of the rising pipe 34 is formed in a substantially square shape (Figure 9) over a predetermined length, the flushing water flowing upward within the rising pipe 34 can be straightened, reducing energy loss and increasing the rate of waste discharge. Moreover, since the base 37d of the cross-section 37 at the highest point T is formed in a substantially horizontal, substantially straight shape (Figure 10), a wide flow path can be secured at the highest point T, allowing a large amount of flushing water and waste to pass over the highest point T with less energy. Through these actions, flushing water and waste can be effectively discharged.
[0057] Furthermore, in the flush toilet of this embodiment, the central axis X in a predetermined section 92 with a roughly square cross-section (Figure 9) is formed in a roughly straight line (Figure 3), which helps to suppress clogging of waste in the riser pipe 34.
[0058] Furthermore, in the flush toilet of this embodiment, the flow path cross-sectional area of the rising pipe 34 increases from the lowest point B to the highest point T (Figure 13), so the flow velocity of the flushing water flowing through the rising pipe 34 can be reduced, and energy loss of the flushing water flow can be suppressed.
[0059] Furthermore, in the flush toilet of this embodiment, the maximum height (H2 to H7) and maximum width (W2 to W7) of the cross-section of the riser pipe 34 are formed to be substantially constant (Figure 13), so that energy loss of the flush water flowing through the riser pipe 34 can be suppressed.
[0060] Furthermore, in the flush toilet of this embodiment, since the cross-section 37 (Figure 10) including the highest point T is roughly square in shape, the portion of the cross-section that is roughly square over a predetermined length and the cross-section 37 at the outlet at the highest point T, where the base 37d is roughly horizontal and roughly straight, can be smoothly connected, thereby suppressing turbulence in the flow of flushing water.
[0061] Although embodiments of the present invention have been described above, various modifications can be made to the embodiments described above. Furthermore, the present invention can also be configured as follows in a preferred configuration. 1. A flush toilet with a wash-down mechanism, The bowl section that receives waste, This bowl section has a water outlet that discharges cleaning water to form a swirling flow, The drain trap pipeline includes a descending pipe connected to the bowl portion and extending downward from the bowl portion, and an ascending pipe connected to the descending pipe and extending upward from the descending pipe, The aforementioned rising pipeline extends from the lowest point of the drain trap pipeline to the highest point that defines the water level in the bowl section. The aforementioned rising pipe is characterized in that the flow channel cross-section at the lowest point is formed in a substantially inverted triangular shape, the flow channel cross-section over a predetermined length is formed in a substantially square shape, and the base of the flow channel cross-section at the highest point is substantially horizontal and substantially straight. 2. The flush toilet according to item 1, wherein the riser pipe is formed in a substantially straight line in a predetermined section in which the cross-sectional area of the flow path is substantially square. 3. The flush toilet according to 1 or 2 above, wherein the upward pipe has an increasing flow path cross-sectional area in at least a portion thereof, from the lowest point to the highest point. 4. The rising pipe is a flush toilet according to any one of items 1 to 3 above, wherein the maximum height and maximum width of the cross-sectional area of the flow path are substantially constant. 5. The flush toilet according to any one of items 1 to 4 above, wherein the rising pipe has a flow path cross-section including the highest point that is formed in a substantially rectangular shape. 6. The flush toilet according to any one of items 1 to 5 above, wherein the rising pipe is provided with a curved section extending over a predetermined distance from the lowest point, and in this curved section, the cross-sectional shape of the flow path of the rising pipe gradually changes from a substantially inverted triangular shape at the lowest point to a substantially square shape. [Explanation of symbols]
[0062] 1 flush toilet 2 Toilet bowl 8 Bowl section 12 Drain trap pipe 22. First water outlet (water outlet section) 24. Second discharge port (discharge section) 32 Descending pipe 32a Exit side 34. Ascent pipeline 34a Top edge 34b Right side 34c bottom edge 34d Left side 38 Entrance 38a Top edge 38b Right side 38c bottom edge 38d Left side 40 Entrance 40a Top edge 40b Right side 40c left side 42 Top 44 Right side first side 45, 49 Connection points 46 Right side second side 48 Left side 1st side 50 Second left side 51 Upper end 52 Bottom end
Claims
1. It is a flush toilet with a wash-down system. The bowl section that receives waste, This bowl section has a water outlet that discharges cleaning water to form a swirling flow, The drain trap pipeline includes a descending pipe connected to the bowl portion and extending downward from the bowl portion, and an ascending pipe connected to the descending pipe and extending upward from the descending pipe, The aforementioned rising pipeline extends from the lowest point of the drain trap pipeline to the highest point that defines the water level in the bowl section. A flush toilet characterized in that, in at least a portion thereof, the flow path cross-sectional area of the rising pipe increases from the lowest point to the highest point, and in the section where the flow path cross-sectional area increases, the maximum height and maximum width of the flow path cross-section of the rising pipe are substantially constant, and the cross-sectional area of the inlet of the descending pipe is substantially the same as the cross-sectional area at the lowest point.
2. The flush toilet according to Claim 1, wherein the rising pipe is provided with a curved section extending over a predetermined distance from the lowest point, and in this curved section, the cross-sectional shape of the flow path of the rising pipe changes from a substantially inverted triangular shape at the lowest point to a substantially square shape.
3. The flush toilet according to claim 1, wherein the maximum width of the flow channel cross-section at the inlet of the descending pipe is formed to be narrower than the maximum width of the flow channel cross-section at the lowest point.
4. The flush toilet according to claim 2 or 3, wherein in the substantially inverted triangular flow channel cross section at the lowest point, the angle with respect to the vertical at the lower part of the side is greater than the angle with respect to the vertical at the upper part of the side.