Flush toilet

Abstract

To provide a flush toilet capable of improving discharge performance of waste by suppressing energy loss occurring when flush water containing waste flows from a lowering pipeline to a riser pipeline of a drain trap pipeline.SOLUTION: A flush toilet 1 of the present invention comprises: a bowl part 8 for receiving waste; water discharge parts 22, 24 for discharging flush water to the bowl part to form a swirling flow; and a drain trap pipeline 12 including a lowering pipeline 32 connected to the bowl part and extending downward from the bowl part, and a riser pipeline 34 connected to the lowering pipeline and extending upward from the lowering pipeline, wherein the lowering pipeline includes an inlet part 38 formed at a connection portion with the bowl part, and an outlet part 40 formed at a connection portion with the riser pipeline, a cross section of the lowering pipeline on the outlet part side, orthogonal to a center axis X of the lowering pipeline, includes an upper edge 40a and two side edges 40b, 40c extending obliquely inward downward from both ends of the upper edge, the upper edge and the two side edges are formed in a circular arc shape, and the flush toilet is characterized in that the two side edges have a substantially triangular shape with a vertex where the two side edges intersect located on a lower side.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a flush toilet, and more particularly to a flush toilet having a trap pipe including a downflow pipe and an upflow pipe. [Background technology]

[0002] In a flush toilet, a drain trap pipe including a descending pipe and an ascending pipe is connected to the bowl portion, and waste excreted in the bowl portion is discharged by flush water. A variety of shapes are used for the cross section perpendicular to the central axis of the descending pipe of this drain trap pipe. For example, in the flush toilet of Patent Document 1, the cross section of the inlet of the descending pipe of the drain trap pipe is approximately triangular, and the outlet is approximately rectangular, and this shape ensures that suspended waste is discharged.

[0003] Furthermore, in the flush toilet of Patent Document 2, the cross sections of both the inlet and outlet of the downflow pipe of the drain trap pipe are approximately rectangular, and this shape makes it less likely for waste or paper to become clogged. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-51883 A [Patent Document 2] JP 2016-98491 A Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, there is a demand for the drain trap pipe of a flush toilet to have a faster start to discharge waste (initial movement), promote straightening of the flow within the drain trap pipe, and also increase the speed at which waste is discharged, and there is a demand for a flush toilet that can achieve both of these. In particular, it is important to promote flow straightening in the drain trap pipe and reduce the energy loss that occurs when flush water containing sewage flows from the descending pipe to the ascending pipe of the drain trap pipe, thereby improving the sewage discharge performance.

[0006] Therefore, the present invention has been made to satisfy conventional demands, and has as its object to provide a flush toilet that can improve waste discharge performance by suppressing the energy loss that occurs when flush water containing waste flows from the descending pipe to the ascending pipe of the drain trap pipe. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention has a bowl section for receiving waste, a water discharge section for discharging cleaning water into the bowl section to form a swirling flow, and a drain trap pipe including a downcomer pipe connected to the bowl section and extending downward from the bowl section, and an upcomer pipe connected to the downcomer pipe and extending upward from the downcomer pipe, wherein the downcomer pipe has an inlet section formed at its connection section with the bowl section, and the downcomer pipe has an outlet section formed at its connection section with the upcomer pipe, and a cross section perpendicular to the central axis of the downcomer pipe on the outlet side of the downcomer pipe has an upper edge and two side edges extending diagonally inward and downward from both ends of the upper edge, the upper edge and the two side edges are formed in an arc shape, and the apex where the two side edges intersect is located on the lower side, forming an approximately triangular shape. In the present invention thus configured, the cross section perpendicular to the central axis of the downcomer pipe at the outlet side of the downcomer pipe has an upper side and two side sides extending diagonally inward downward from both ends of the upper side, the upper side and the two side sides are formed in an arc shape, and the apex where the two side sides intersect is located at the lower side, so that the swirling state is maintained when the swirling flow generated in the bowl part flows into the downcomer pipe of the drain trap pipe, and this swirling flow is rectified by flowing along the two side sides of the approximately triangular cross section at the outlet side of the downcomer pipe, so that the energy loss generated when the flush water containing the sewage flows from the downcomer pipe to the upcomer pipe can be suppressed. In addition, the rectification of the flush water can increase the discharge speed of the sewage. Furthermore, at the outlet side of the downcomer pipe, the flush water containing the sewage flows along the two side sides extending diagonally inward downward, so that the flow is directed upward, so that the rectification when it flows from the downcomer pipe to the upcomer pipe can be more effectively performed. As a result, according to the present invention, waste discharge performance is improved.

[0008] In the present invention, preferably, the approximately triangular cross-sectional shape of the descending pipeline on the outlet side has two side edges extending diagonally inward and downward from both ends of the upper edge, each of which has a first side edge and a second side edge extending downward from the first side edge, and the second side edge is inclined more inward than the first side edge. In the present invention configured in this manner, the second side edge of the approximately triangle is inclined more inward than the first side edge, so that the cleaning water containing dirt can be rectified further upward, thereby further reducing energy loss when the cleaning water containing dirt flows from the descending pipe to the ascending pipe; and further, because the first side edge of the approximately triangle is not inclined more inward than the second side edge, the cross-sectional area of ​​the outlet side of the descending pipe can be made larger, thereby improving dirt removal performance.

[0009] In the present invention, the length in the height direction from the connection point between the first side and the second side of the approximately triangular cross-sectional shape to the bottom end is preferably longer than the length in the height direction from the upper end of the approximately triangle to the connection point. In the present invention configured in this manner, the height length from the connection point between the first and second side edges of the approximately triangular cross-sectional shape to the bottom end is longer than the height length from the upper end of the approximately triangle to the connection point, so the length of the second side edge is longer, which promotes flow straightening and reduces energy loss when cleaning water containing dirt flows from the descending pipe to the ascending pipe.

[0010] In the present invention, preferably, a cross section of the inlet portion of the downcomer pipe perpendicular to the central axis of the downcomer pipe is substantially rectangular. In the present invention thus configured, the cross section of the inlet of the downcomer pipe perpendicular to the central axis of the downcomer pipe is substantially rectangular, so that the cross-sectional area of ​​the inlet of the downcomer pipe is large, and this makes it possible to hasten the start of discharge (initial movement) of flush water containing waste. Furthermore, by combining this with the substantially triangular shape on the outlet side of the downcomer pipe, it is possible to both hasten the start of discharge of waste and promote flow straightening.

[0011] In the present invention, preferably, the area of ​​a cross section perpendicular to the central axis of the downcomer pipe from the inlet to the outlet of the downcomer pipe is approximately constant. In the present invention configured in this manner, by making the cross-sectional area perpendicular to the central axis of the descending pipeline from the inlet to the outlet of the descending pipeline approximately constant, even if the cross-sectional shape of the descending pipeline changes, the change in the overall cross-sectional area of ​​the descending pipeline can be suppressed, and energy loss associated with the change in cross-sectional shape can be suppressed.

[0012] In the present invention, preferably, a cross section of the outlet portion of the downcomer pipe perpendicular to the central axis of the downcomer pipe is substantially triangular. In the present invention thus configured, the cross section of the outlet of the descending pipe perpendicular to the central axis of the descending pipe is substantially triangular, so that the swirling flow generated in the bowl section flows along the sides of the substantially triangular cross section of the outlet of the descending pipe, and is rectified, thereby making it possible to suppress the energy loss that occurs when the flush water containing the waste flows from the descending pipe to the ascending pipe. Also, the rectification makes it possible to increase the discharge speed of the waste. Furthermore, at the outlet of the descending pipe, the flush water containing the waste flows along the sides that extend diagonally inward downward, and thus becomes an upward flow, so that the rectification when it flows from the descending pipe to the ascending pipe is more effectively performed.

[0013] In the present invention, preferably, the maximum height of a cross section perpendicular to the central axis of the downcomer pipe from the inlet to the outlet of the downcomer pipe is approximately constant. In the present invention configured in this manner, the maximum vertical height of the cross section perpendicular to the central axis of the descending pipe from the inlet to the outlet is approximately constant, thereby preventing clogging by waste. Effect of the Invention

[0014] The flush toilet of the present invention has the objective of providing a flush toilet that can improve waste discharge performance by reducing the energy loss that occurs when flush water containing waste flows from the descending pipe to the ascending pipe of the trap pipe. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a plan view showing a flush toilet according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] 3 is a cross-sectional view taken along line VV in FIG. 2. [Figure 6]FIG. 2 is a diagram showing a schematic cross-sectional shape of an outlet portion of a descending pipe of a trap pipe of a flush toilet according to one embodiment of the present invention. [Figure 7] 1 is a cross-sectional view showing overlapping cross sections of an inlet portion and an outlet portion of a downcomer pipe. FIG. [Figure 8] 3 is a comparative diagram showing a trap pipe of a flush toilet according to an embodiment of the present invention and the trap pipes of Comparative Examples 1 and 2. FIG. [Figure 9] 1 is a diagram showing the relationship between the percentage of residual waste and time in a drain trap pipe of a flush toilet according to an embodiment of the present invention and in the drain trap pipes of Comparative Examples 1 and 2. FIG. [Figure 10] FIG. 10 is a partially enlarged diagram of part A in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Next, a flush toilet according to an embodiment of the present invention will be explained with reference to Figures 1 to 7. First, the basic structure of a flush toilet according to an embodiment of the present invention will be explained 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 line II-II in Figure 1.

[0017] As shown in Figures 1 and 2, reference numeral 1 denotes a flush toilet according to an embodiment of the present invention, which is a wash-down toilet in which waste is washed away by the flowing water caused by the drop in water inside the bowl, and which comprises a toilet body 2 and a water storage tank 4 for storing flushing water for cleaning the toilet body 2. The toilet body 2 is made of ceramic with a glaze layer formed on its surface, with a skirt portion 6 formed on the lower portion and a bowl portion 8 formed in the front portion of the upper half. A common water passage 10 is formed at the upper rear portion of the bowl portion 8, the upstream end of which communicates with the water storage tank 4, and furthermore, a drain trap pipe 12 for discharging waste is formed at the lower rear portion of the bowl portion 8.

[0018] The above-mentioned water storage tank 4 is a flush water source, and a drain valve 14 is provided within this water storage tank 4, which is opened and closed by an operating lever (not shown). Note that this embodiment can also be applied to direct pressure flush toilets in which flush water is supplied directly from the water supply, without the water storage tank 4, and flush toilets of the type in which flush water is supplied by a flush valve.

[0019] 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 peripheral surface 18a of the rim portion 18 has an inwardly overhanging shape so that swirling flush water, described below, does not splash out to the outside.

[0020] A first water outlet 22 for spouting flush water is formed on the inner circumferential surface of the rim portion 18 of the bowl portion 8, slightly rearward of the center on the left side as viewed from the front, and a second water outlet 24 is formed on the rear right side (downstream side) as viewed from the front. These first water outlet 22 and second water outlet 24 are designed to form a swirling flow that swirls in the same direction (counterclockwise in FIG. 1).

[0021] Additionally, the common water passage 10 formed at the upper rear part of the flush toilet 1 described above branches toward the front of the toilet into a first water passage 26 and a second water passage 28. The first water passage 26 is for supplying flush water to the first water outlet 22, and the second water passage 28 is for supplying flush water to the second water 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 that is separate from the toilet body.

[0022] 2, the drain trap pipe 12 is provided with a descending pipe 32 that is connected to a lower portion 20a of the recess 20, which is a part of the recess 20 of the bowl portion 8, and extends rearward and downward, and an ascending pipe 34 that is connected to the descending pipe 32 and extends upward. Furthermore, the ascending pipe 34 is connected to a downstream drain pipe 36, and the drain pipe 36 is connected to a drain socket (not shown) or the like, so that waste is drained to a drain provided in a floor or wall. The descending pipe 32 has an inlet portion 38 where the lower portion 20a of the recess 20 and the descending pipe 32 are connected and where the lower portion 20a of the recess 20 switches to the descending pipe 32. In this embodiment, the inlet portion 38 is a location where the rate of change in the cross-sectional area of ​​the connecting portion between the lower portion 20a of the recess 20 and the descending pipe 32 becomes small or zero, but the position of the inlet portion 38 varies somewhat depending on the shape of the connecting portion between the lower portion 20a of the recess 20 and the descending pipe 32. Furthermore, the descending pipe 32 has an outlet portion 40 connected to the ascending pipe 34. The descending pipe 32 descends from the inlet 38 to the outlet 40. The inlet 38 and the outlet 40 of the descending pipe 32 are provided perpendicular to the central axis X of the descending pipe 32 (which is also the central axis of the drain trap pipe). The outlet 40 is located at the lowest point of the drain trap pipe 12. Before cleaning, at least a part of the recess 20 and the drain trap pipe 12 are filled with water to form a water seal. In this embodiment, in order to form a certain amount of water seal, the top of the ascending pipe 34 is located higher than the inlet 38 of the descending pipe 32, so that the descending pipe 32 and a part of the recess 20 connected to the descending pipe 32 can be filled with water to form a water seal.

[0023] Next, the cross-sectional shapes of the descending pipe 38 and the ascending pipe 40 will be described with reference to Figures 3 to 5. Figure 3 is a cross-sectional view taken along line III-III in Figure 2 (a cross-sectional view of the inlet of the descending pipe), Figure 4 is a cross-sectional view taken along line IV-IV in Figure 2 (a cross-sectional view of the outlet of the descending pipe), and Figure 5 is a cross-sectional view taken along line V-V in Figure 2 (a cross-sectional view of the ascending pipe).

[0024] First, as shown in Fig. 3, the cross-sectional shape of the inlet portion 38 of the descending pipe 32 is substantially rectangular. The cross-section of the inlet portion 38 has 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 horizontal direction than the lower side 38c. In addition, the right side 38b and the left side 38d are gently inclined inward, and are provided so as to be symmetrical with respect to the line connecting the apex of the upper side 38a and the lowest point of the lower side 38c. 4, the cross-sectional shape of the outlet 40 of the downcomer pipe 32 is substantially triangular. The cross section of the outlet portion 40 has an upper side 40a, a right side 40b, and a left side 40c. Here, the side 40b and the left side 40c are arc-shaped. Next, as shown in Fig. 5, the cross-sectional shape of the up-down pipe 34 is a substantially rectangular shape that is the same from the upstream side to the downstream side. The cross section of the up-down pipe 34 has an upper side 34a, a right side 34b, a lower side 34c, and a left side 34d, and the upper side 34a is longer in the horizontal direction than the lower side 34c. In addition, the right side 33b and the left side 34d are gently inclined inward.

[0025] Although not shown, the cross-sectional shape of the descending pipe 32 gradually changes from a substantially square shape to a substantially triangular shape from the middle of the inlet portion 38 and the outlet portion 40 toward the outlet portion 40. In particular, the cross-sectional shape of the outlet portion 32a (see FIG. 2) of the descending pipe 32 is a substantially triangular shape as shown in FIG. 4 in the range of 50 to 100 (or a shorter range including 100) of the descending pipe 32, when the inlet portion 38 is 0 and the outlet portion 40 is 100. By making the rate of change of the cross-sectional shape of the descending pipe 32 constant, it is possible to further suppress energy loss caused by the change of the cross-sectional shape. It is also possible to make the rate of change non-uniform as long as it is within a range in which energy loss can be suppressed to a certain extent. The cross-sectional shape of the ascending pipe 34 is approximately triangular on the upstream side to maintain continuity with the approximately triangular outlet portion 40 of the descending pipe 32, but is approximately rectangular on the downstream side as described above. Note that the cross-sectional shape of the ascending pipe 34 may be made approximately triangular without changing it.

[0026] 3 to 5, 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 outlet 40 of the descending pipe 32, and the maximum height H3 of the cross section perpendicular to the central axis X of the ascending pipe 34 are substantially constant. Therefore, the maximum height of the cross section perpendicular to the central axis X of the drain trap pipe 12 is substantially constant. Note that, if the height is substantially constant up to the middle of the downstream side of the outlet 40, the height can be changed on the downstream side of the ascending pipe 34.

[0027] Next, the cross-sectional shape of the outlet portion 40 of the descending pipe 32 will be described in detail with reference to Figure 6. Figure 6 is a diagram showing a schematic cross-sectional shape of the outlet portion of the descending pipe of the drain trap pipe of a flush toilet according to one embodiment of the present invention. As shown in FIG. 6, the cross-sectional shape of the outlet portion 40 of the descending pipe 32 is approximately triangular as described above. This approximately triangular shape will be specifically described. FIG. 6 shows the shape of the inner wall of the outlet portion 40 of the descending pipe 32. The outlet portion 40 has an approximately triangular cross-sectional shape due to an upper side 42, a first right side 44, a second right side 46 connected to the first right side 44 by a connection point 45, a first left side 48, and a second left side 50 connected to the first left side 48 by a connection point 49. The upper side 42, the first right side 44, the second right side 46, the first left side 48, and the second left side 50 are all arc-shaped.

[0028] In addition, the center of the upper side 42 of the outlet portion 40 of the descending pipe 32 is the upper end 51 of the cross section, and the intersection of the second right side 46 and the second left side 50 is the lower end 52 of the cross section. Here, in the cross section of outlet 40 of descending pipe 32, height (distance) b from connecting parts 45, 49 to lower end 52 is greater than height (distance) a from upper end 51 to connecting parts 45, 49 (i.e., there is a relationship of b>a). The cross-sectional shape of outlet 10 is provided so as to be symmetrical with respect to the line connecting upper end 51 and lower end 52.

[0029] As shown in FIG. 6, the cross section of the outlet portion 40 of the descending pipe 32 is shaped so that the inward inclination angle β of the second right side edge 46 with respect to the vertical direction (specifically, the inclination angle of the tangent drawn at the midpoint of the first right side edge 44 with respect to the vertical direction) is greater than the inward inclination angle α of the first right side edge 44 with respect to the vertical direction (specifically, the inclination angle of the tangent drawn at the midpoint of the first right side edge 44 with respect to the vertical direction) (i.e., there is a relationship of β>α). Similarly, the cross section of the outlet portion 40 of the descending conduit 32 is shaped so that the inward inclination angle β of the left second side edge 50 with respect to the vertical direction (specifically, the inclination angle of the tangent drawn at the midpoint of the left second side edge 50 with respect to the vertical direction) is greater than the inward inclination angle α of the left first side edge 48 with respect to the vertical direction (specifically, the inclination angle of the tangent drawn at the midpoint of the left first side edge 48 with respect to the vertical direction) (i.e., there is a relationship of β>α).

[0030] 6, in the cross section of the outlet portion 40 of the downcomer pipe 32, the angle γ formed by a tangent drawn at the center point of the second right side edge 46 and a tangent drawn at the center point of the second left side edge 50 is 105 degrees. Here, the angle γ is preferably between 85 degrees and 125 degrees. The angle γ is larger than the angles formed by the top side 42 and the first left side edge 48 and the first right side edge 44, respectively.

[0031] Next, the cross-sectional areas of the inlet portion 38 and the outlet portion 40 of the downcomer pipe 32 will be described with reference to Fig. 7. Fig. 7 is a cross-sectional view showing the cross sections of the inlet portion and the outlet portion of the downcomer pipe overlapping each other. 7, the cross-sectional shape of the inlet portion 38 of the downcomer pipe 32 is indicated by a dashed line, and the cross-sectional shape of the outlet portion 40 is indicated by a solid line. Here, the cross-sectional area S1 of the inlet portion 38 and the cross-sectional area S2 of the outlet portion 40 are substantially the same. Therefore, the cross-sectional height H1 of the inlet portion 38 and the cross-sectional height H2 of the outlet portion 40 are substantially constant, and the cross-sectional area is made substantially constant by making the cross-sectional width W1 of the inlet portion 38 larger than the cross-sectional width W2 of the outlet portion 40. Also, compared to the substantially rectangular inlet portion 38, the outlet portion 40 is substantially triangular, and therefore the bottom surface of the cross section is narrower.

[0032] Next, the three characteristics required for a flush toilet - "speed of discharge start," "straightening of flow in the downcomer pipe," and "discharge speed" - will be explained by comparing a flush toilet 1 according to this embodiment with prior art flush toilets according to Comparative Examples 1 and 2. Fig. 8 is a comparison diagram showing a comparison of the trap pipe of a flush toilet according to an embodiment of the present invention and the trap pipes of Comparative Examples 1 and 2, Fig. 9 is a diagram showing the relationship between the residual proportion of waste and time for the drain trap pipe of a flush toilet according to an embodiment of the present invention and the drain trap pipes of Comparative Examples 1 and 2, and Fig. 10 is a partial enlarged diagram of part A in Fig. 9.

[0033] 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 of the inlet of the downcomer pipe is approximately rectangular, the cross-sectional shape perpendicular to the central axis of the outlet of the downcomer pipe is approximately rectangular, and the cross-sectional shape perpendicular to the central axis of the upcomer pipe is approximately rectangular. In the flush toilet of Comparative Example 2, the cross-sectional shape perpendicular to the central axis of the inlet of the downcomer pipeline is approximately triangular, the cross-sectional shape perpendicular to the central axis of the outlet of the downcomer pipeline is approximately rectangular, and the cross-sectional shape perpendicular to the central axis of the upcomer pipeline is approximately rectangular. In the flush toilet 1 according to this embodiment, as described above, the cross-sectional shape perpendicular to the central axis of the inlet of the downcomer pipeline is approximately rectangular, the cross-sectional shape perpendicular to the central axis of the outlet of the downcomer pipeline is approximately triangular, and the cross-sectional shape perpendicular to the central axis of the upcomer pipeline is approximately rectangular.

[0034] In order to confirm the three characteristics described above of the flush toilets according to Comparative Example 1, Comparative Example 2, and the embodiment, experiments were also conducted using artificial filth (using a large amount of fine particles with roughly the same mass as filth), and the results shown in Figures 8 and 9 were obtained. First, as shown in FIG. 8, in terms of "speed of discharge start (initial movement)," the flush toilets according to Comparative Example 1 and the embodiment were fast (◯), while Comparative Example 2 was a little slower (Δ). With regard to flow straightening within the downflow pipe, the flush toilets according to Comparative Example 2 and the embodiment were rated good (◯), while Comparative Example 1 was poor (△). Regarding waste discharge speed, the flush toilets according to Comparative Example 1 and the embodiment were fast (◯), while Comparative Example 2 was slightly slower (Δ).

[0035] Next, as shown in Figures 9 and 10, when waste is discharged from the bowl section into the drain trap pipe, there is 100% waste in the bowl section when the discharge starts (0 seconds), and when the discharge ends, there is no waste left in the bowl (almost zero). Two seconds after flushing begins, the waste in the bowl begins to be discharged into the drain trap pipe due to the flow of water caused by the difference in head and fall within the bowl. At this time, as shown in Figure 10, the flush toilet of this embodiment shown by the solid line starts to discharge waste the fastest, 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, the slowest.

[0036] From the above, it has been confirmed that the flush toilet according to this embodiment achieves all three characteristics required for a flush toilet: "speed of discharge start," "straightening of the flow in the downcomer pipe," and "discharge speed."

[0037] Next, the effects of the flush toilet according to the embodiment of the present invention described above will be explained. First, in the flush toilet 1 of this embodiment, the cross section of the outlet side 32a of the descending pipe 32 perpendicular to the central axis X of the descending pipe 32 comprises an upper side 40a and two side sides 40b, 40c extending diagonally inward and downward from both ends of the upper side 40a, and these upper side 40a and the two side sides 40b, 40c are formed in an arc shape, and the apex where the two side sides 40b, 40c intersect is located on the lower side, so that when the swirling flow generated in the bowl portion 8 flows into the descending pipe 32 of the drain trap pipe 12, the swirling state is maintained, and this swirling flow is rectified by flowing along the two side sides 40b, 40c of the approximately triangular shape at the outlet side 32a of the descending pipe 32, which has a cross section of approximately triangular shape, and this makes it possible to reduce the energy loss that occurs when flush water containing waste flows from the descending pipe 32 to the ascending pipe 34.

[0038] Also, by rectifying the flow of flush water, the waste removal speed can be increased. Furthermore, at the outlet side 32a of the descending pipe 32, flush water containing waste flows downward along the two side edges 40b, 40c that extend diagonally inward, causing the flow to face upward, so the flow is more effectively rectified when it flows from the descending pipe 32 to the ascending pipe 34. As a result, with the flush toilet 1 according to this embodiment, waste discharge performance is improved.

[0039] Next, in the flush toilet 1 according to this embodiment, the second right side edge 46 and the second left side edge 48 of the approximately triangular shape are inclined more inward than the first right side edge 44 and the first left side edge 48, respectively, so that the flush water containing waste can be rectified further upward, thereby further reducing energy loss when the flush water containing waste flows from the descending pipe 32 to the ascending pipe 34, and further, because the first right side edge 44 and the first left side edge 48 of the approximately triangular shape are not inclined more inward than the second right side edge 46 and the second left side edge 50, respectively, the cross-sectional area of ​​the outlet side 32a of the descending pipe 32 can be made larger accordingly, improving waste removal performance. Because the outlet section 32 and the outlet side 32a of the descending pipeline 32 are made into this approximately triangular shape, the cross-sectional shape gradually changes from approximately a square to approximately a triangle from halfway between the inlet section 38 and the outlet section 40 toward the outlet section 40, thereby preventing a sudden change in the cross-sectional shape, thereby further reducing energy loss.

[0040] Next, in the flush toilet 1 according to this embodiment, the height length b from the connection point 45 of the first right side edge 44 and the second right side edge 46 to the bottom end 52 of the approximately triangular cross-sectional shape of the outlet side 32a of the descending pipe 32, and the height length b from the connection point 49 of the first left side edge 48 and the second left side edge 50 to the bottom end 52 are each longer than the height length a from the upper end 51 of the approximately triangle to the connection points 45, 49, and so the lengths of the second right side edge 46 and the second left side edge 50 are each longer, which promotes flow straightening and reduces energy loss when flush water containing waste flows from the descending pipe 32 to the ascending pipe 34.

[0041] Next, in the flush toilet 1 according to this embodiment, the cross section of the inlet 38 of the descending conduit 32 that is perpendicular to the central axis X of the descending conduit 32 is approximately rectangular, so the cross-sectional area of ​​the inlet 38 of the descending conduit 32 is large, which makes it possible to hasten the start of the discharge (initial movement) of flush water containing waste. Furthermore, by combining this with the approximately triangular shape of the outlet side 32a of the descending conduit 32, it is possible to both hasten the start of the discharge of waste and promote flow straightening.

[0042] Next, in the flush toilet 1 according to this embodiment, by making the area of ​​the cross section perpendicular to the central axis X of the descending conduit 32 from the inlet 38 to the outlet 40 of the descending conduit 32 approximately constant, even if the cross-sectional shape of the descending conduit 32 changes, it is possible to reduce change in the overall cross-sectional area of ​​the descending conduit 32, and thus reduce energy loss associated with changes in the cross-sectional shape.

[0043] Next, in the flush toilet 1 according to this embodiment, the cross section of the outlet portion 38 of the descending pipe 32 perpendicular to the central axis X of the descending pipe 32 is approximately triangular, so the swirling flow generated in the bowl portion 8 flows along the side of the approximately triangular cross section of the outlet portion 40 of the descending pipe 32 and is rectified, thereby making it possible to reduce energy loss that occurs when flush water containing waste flows from the descending pipe 32 to the ascending pipe 34. In addition, rectification makes it possible to increase the waste discharge speed. Furthermore, at the outlet portion 40 of the descending pipe 32, flush water containing waste flows along the side that extends diagonally inward downward, resulting in an upward flow, so rectification is more effectively performed when it flows from the descending pipe 32 to the ascending pipe 34.

[0044] Next, in the flush toilet 1 according to this embodiment, the maximum vertical heights H1, H2, H3 of the cross section perpendicular to the central axis X of the descending conduit 32 from the inlet portion 38 to the outlet portion 40 of the descending conduit 32 are approximately constant, which makes it possible to prevent clogging with waste. [Explanation of symbols]

[0045] 1 flush toilet 2 Toilet bowl body 8 Bowl section 12 Drain trap line 22 First outlet 24 Second outlet 32 Descending pipe 32a Exit side 34 Ascending Pipe 34a Top 34b Right side 34c Bottom 34d Left side 38 Entrance 38a Top 38b Right side 38c Bottom 38d Left side 40 Exit section 40a Top 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. A bowl portion for receiving waste; a water discharge section that discharges wash water into the bowl section to form a swirling flow; a drain trap pipe including a downcomer pipe connected to the bowl portion and extending downward from the bowl portion, and an upcomer pipe connected to the downcomer pipe and extending upward from the downcomer pipe, the downcomer conduit has an inlet portion formed at a connection with the bowl portion, the downcomer conduit has an outlet formed at a connection with the upcomer conduit; A flush toilet characterized in that a cross section perpendicular to the central axis of the downcomer pipe on the outlet side of the downcomer pipe has an upper side and two side sides extending diagonally inward and downward from both ends of the upper side, the upper side and the two side sides are formed in an arc shape, and the apex where the two side sides intersect is located on the lower side, forming a roughly triangular shape.

2. 2. The flush toilet according to claim 1, wherein the approximately triangular cross-sectional shape of the outlet portion of the descending pipe has two side edges extending diagonally inward and downward from both ends of an upper edge, each of which comprises a first side edge and a second side edge extending downward from the first side edge, the second side edges being inclined more inward than the first side edges.

3. 3. The flush toilet according to claim 2, wherein the length in the height direction from the connection point between the first side edge and the second side edge of the approximately triangular cross-sectional shape to its lower end is longer than the length in the height direction from the upper end of the approximately triangle to the connection point.

4. 4. The flush toilet according to claim 1, wherein a cross section of the inlet portion of the downcomer pipe perpendicular to a central axis of the downcomer pipe is substantially rectangular.

5. 5. The flush toilet according to claim 1, wherein the area of ​​a cross section perpendicular to a central axis of the descending pipe from the inlet to the outlet is approximately constant.

6. 6. The flush toilet according to claim 1, wherein a cross section of the outlet portion of the descending pipe perpendicular to a central axis of the descending pipe is substantially triangular.

7. 7. The flush toilet according to claim 1, wherein a maximum height of a cross section of the descending pipe perpendicular to a central axis of the descending pipe from the inlet portion to the outlet portion is approximately constant.

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