Flush toilet bowl

Abstract

To provide a flush toilet bowl capable of effectively discharging cleaning water and wastes even in a wash-out type toilet in which a bowl part is washed by swirling flow.SOLUTION: The present invention is a wash-out type toilet (1) comprising a bowl part (8) that receives wastes, a water discharge part (22, 24) that discharges cleaning water into this bowl part to form a swirling flow, a descending conduit (32) connected to the bowl part and extending downward from the bowl part, and a drain trap conduit (12) connected to this descending conduit and including an ascending conduit (34) extending upward from the descending conduit. The ascending conduit extends from a lowest point (B) of the drain trap conduit to a highest point (T) which defines the level of the pooled water in the bowl part. The ascending conduit is characterized in that the cross-section of the flow channel at the lowest point is formed as an inverted triangle, the cross-section of the flow channel is formed in a substantially rectangular shape over a predetermined length, and the bottom of the cross-section of the flow channel at the highest point is substantially a straight line and is substantially horizontal.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a flush toilet, and more particularly to a wash-down type 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 using flush water. A variety of shapes are used for the cross section of the drain trap pipe, which is a cross section perpendicular to the central axis of the drain trap pipe. For example, in the flush toilet of Patent Document 1, the cross section of the drain trap pipe at the inlet is approximately triangular, the cross section at the lowest point is approximately rectangular, and the cross section of the drain trap pipe at the inlet is a combination of a circular arc and a straight line. These shapes ensure that suspended waste is discharged.

[0003] Furthermore, in the flush toilet of Patent Document 2, the flow path cross section of the drain trap pipe is formed into a shape that combines arcs and straight lines, or into a roughly rectangular shape, which makes it less likely to become clogged with waste or paper.

[0004] Also in the flush toilet of Patent Document 3, the flow path cross section of the drain trap pipe is formed into a shape that combines arcs and straight lines, or into an approximately rectangular shape, and this shape improves the discharge performance of waste and flush water. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-51883 A [Patent Document 2] JP 2016-98491 A [Patent Document 3] JP 2017-145631 A Summary of the Invention [Problem to be solved by the invention]

[0006] 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.

[0007] In particular, in wash-down type flush toilets, there is essentially no force acting to suck up the flush water in the bowl due to siphon action, so the flush water and waste must overcome the drain trap pipe and be discharged only by the pushing force of the flush water flowing into the bowl.

[0008] Additionally, in flush toilets of the type that clean the bowl section with a swirling flow of flush water discharged from the spout, the instantaneous flow rate of flush water discharged from the spout cannot be set high, and must be kept relatively low. This weakens the pushing force of the flush water flowing into the bowl section, making it more difficult for the flush water and waste to overcome the drain trap pipe.

[0009] Therefore, an object of the present invention is to provide a flush toilet that can effectively discharge flush water and waste, even in a wash-down toilet that cleans the bowl portion with a swirling flow. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the present invention is a wash-down type flush toilet comprising a bowl portion for receiving waste, a water outlet portion for spouting flushing water into the bowl portion to form a swirling flow, a downcomer conduit connected to the bowl portion and extending downward from the bowl portion, and a drain trap pipe including an upcomer conduit connected to the downcomer conduit and extending upward from the downcomer conduit, the upcomer conduit extending from the lowest point of the drain trap pipe to a highest point which determines the accumulated water level in the bowl portion, the upcomer conduit having a flow path cross section at the lowest point which is formed in an approximately inverted triangular shape and a flow path cross section over a predetermined length which is formed in an approximately rectangular shape, and the base of the flow path cross section at the highest point is approximately horizontal and approximately straight.

[0011] According to the present invention configured as described above, the cross section of the flow path at the lowest point of the ascending pipe is formed in a substantially inverted triangular shape, so that the vector of the flow from the descending pipe to the ascending pipe can be smoothly converted, and the flush water can be made to flow into the ascending pipe without losing much of the energy of the flow pushed into the descending pipe from the bowl section. In addition, the cross section of the flow path is formed in a substantially rectangular shape over a predetermined length of the ascending pipe, so that the flush water flowing upward in the ascending pipe can be rectified, energy loss can be suppressed, and the discharge speed of the waste can be increased. Furthermore, the base of the cross section of the flow path at the highest point is formed in a substantially horizontal, substantially linear shape, so that a wide flow path can be secured at the highest point, and a large amount of flush water and waste can overcome the highest point with little energy. These actions allow the flush water and waste to be effectively discharged.

[0012] In the present invention, the ascending pipe is preferably formed such that, in a predetermined section where the flow passage cross section is substantially rectangular, the central axis thereof is substantially linear. According to the present invention thus configured, the central axis of a predetermined section of the flow passage having a substantially rectangular cross section is formed substantially linearly, so that clogging of the upflow pipe with sewage can be suppressed.

[0013] In the present invention, preferably, at least a portion of the riser pipe has a flow path cross-sectional area that increases from the lowest point to the highest point. According to the present invention configured in this manner, the flow path cross-sectional area of ​​the ascending pipe increases from the lowest point to the highest point, so that the flow velocity of the cleaning water flowing through the ascending pipe can be reduced and energy loss in the flow of the cleaning water can be suppressed.

[0014] In the present invention, the uprising pipe preferably has a flow passage cross section with a substantially constant maximum height and a substantially constant maximum width. According to the present invention configured in this manner, the maximum height and maximum width of the flow path cross section of the uprising pipe are formed to be approximately constant, so that energy loss in the flow of cleaning water flowing through the uprising pipe can be suppressed.

[0015] In the present invention, the uprising pipe is preferably formed so that a flow passage cross section including the highest point is substantially rectangular. According to the present invention configured in this manner, the flow path cross section including the highest point is made approximately rectangular, so that the flow path cross section over a specified length can be smoothly connected to the approximately rectangular portion of the flow path cross section at the highest point, where the base is approximately horizontal and linear, thereby suppressing disturbance in the flow of cleaning water.

[0016] In the present invention, preferably, the ascending pipe has a curved portion over a predetermined section from the lowest point, and in this curved portion, the flow path cross-sectional shape of the ascending pipe gradually changes from a substantially inverted triangular shape at the lowest point to a substantially rectangular shape. According to the present invention configured in this manner, at the curved section, the flow path cross-sectional shape of the ascending pipe gradually changes from an approximately inverted triangular shape at the lowest point to an approximately rectangular shape, so that the flow resistance when transitioning from the approximately inverted triangular flow path cross-section to the approximately rectangular flow path cross-section can be suppressed, and cleaning water and waste can be effectively discharged. Effect of the Invention

[0017] According to the flush toilet of the present invention, flush water and waste can be effectively discharged even in a wash-down toilet that cleans the bowl portion with a swirling flow. [Brief description of the drawings]

[0018] [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. 2 is an enlarged cross-sectional view showing a drain trap pipe of a flush toilet according to an embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] 4 is a cross-sectional view taken along line VV in FIG. 3. [Figure 6] 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] 8 is a cross-sectional view taken along line VIII-VIII in FIG. 3. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. [Figure 10] FIG. 4 is a cross-sectional view taken along line XX in FIG. [Figure 11] FIG. 2 is a diagram showing a schematic cross-sectional shape of an inlet portion of an ascending pipe of a drain trap pipe of a flush toilet according to an embodiment of the present invention. [Figure 12] 1 is a cross-sectional view showing overlapping cross sections of an inlet portion and an outlet portion of a downcomer pipe. FIG. [Figure 13] 1 is a cross-sectional view showing cross sections from an inlet of an ascending pipe to an upper cross section, the cross sections being overlapped with each other. [Figure 14] 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 15] 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 16] FIG. 16 is a partially enlarged diagram of part A in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] 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.

[0020] 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.

[0021] 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.

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

[0023] A first water outlet 22, which is a water outlet section that spouts 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, which is also a water outlet section, 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).

[0024] 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.

[0025] Here, the first water outlet 22 and the second water outlet 24 discharge flush water along the inner circumferential surface 18a of the overhanging rim portion 18, and the flush water swirling along the inner circumferential surface 18a flows down little by little, cleaning the inner wall surface of the bowl portion 8. At this time, the instantaneous flow rate of flush water discharged from each water outlet is controlled so that the flush water discharged from the first water outlet 22 and the second water outlet 24 does not exceed the rim portion 18 and splash out outside the bowl portion 8.

[0026] 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.

[0027] The descending pipe 32 has an inlet 38 where the lower part 20a of the recess 20 and the descending pipe 32 are connected and where the lower part 20a of the recess 20 switches to the descending pipe 32. In this embodiment, the inlet 38 of the descending pipe 32 is a location where the rate of change in the cross-sectional area of ​​the connecting part of the lower part 20a of the recess 20 and the descending pipe 32 becomes small or zero, but the position of the inlet 38 is made to vary somewhat depending on the shape of the connecting part of the lower part 20a of the recess 20 and the descending pipe 32. Furthermore, the descending pipe 32 is connected to an 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 the inlet 38 of the descending pipe 32 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 a flow path cross section 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 part of the recess 20 and the drain trap pipe 12 are filled with accumulated water to form a water seal. In this embodiment, in order to form a certain amount of water seal, the highest point T of the drain trap pipe 12 is located at a higher position 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. 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 pipe 34 is a pipe connected to the downstream side of the descending pipe 32 at the lowest point B, and extends from the lowest point B to the highest point T. As described later, the ascending pipe 34 has a flow passage cross section formed in a substantially inverted triangle shape at the lowest point B, and a flow passage cross section formed in a substantially rectangular shape in a predetermined section. Furthermore, the ascending pipe 34 is provided with a curved portion from the lowest point B to a predetermined section, and the shape of the flow passage cross section gradually changes from an inverted triangle shape to a substantially rectangular shape in this curved portion. Moreover, the base of the flow passage cross section at the highest point T is formed in a substantially horizontal, substantially linear shape. In this embodiment, the ascending pipe 34 is formed so that the predetermined section in which the flow passage 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 rising pipe 34 above the highest point T, and flush water and waste flowing out from the rising pipe 34 flow through this space 35 into the drain pipe 36. That is, during toilet flushing, the accumulated water and waste in the bowl section 8 are swept away by the flush water flowing into the bowl section 8, and pass over the highest point T of the rising pipe 34, enter the space 35, and fall into the drain pipe 36. Here, since 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 rising pipe 34, even when the flush water and waste pass over the highest point T, the space 35 does not become substantially full of water. Furthermore, since the cross-sectional area of ​​the flow path of the drain pipe 36 provided downstream of the space 35 is also sufficiently wider than the cross-sectional area of ​​the flow path of the rising pipe 34, the drain pipe 36 does not become substantially full of water either. Therefore, the flush toilet 1 of this embodiment does not substantially have a siphon effect.

[0031] Next, the cross-sectional shapes of the descending pipe 32 and the ascending pipe 34 will be described with reference to Figs. 3 to 9. Fig. 3 is a cross-sectional view showing an enlarged view of the drain trap pipe of the toilet body. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3 (cross-sectional view of the inlet of the descending pipe), and Fig. 5 is a cross-sectional view taken along line V-V in Fig. 3 (cross-sectional view of the inlet of the ascending pipe). Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 3 (first cross-sectional view of the ascending pipe), Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 3 (second cross-sectional view of the ascending pipe), Fig. 8 is a cross-sectional view taken along line VIII-VIII in Fig. 3 (third cross-sectional view of the ascending pipe), Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 3 (cross-sectional view of the upper part of the ascending pipe), and Fig. 10 is a cross-sectional view taken along line X-X in Fig. 3 (cross-sectional view of the outlet of the ascending pipe). It should be noted that the cross sections of the descending pipe 32 and the ascending pipe 34 shown in FIGS. 4 to 10 all correspond to “flow path cross sections” cut in a direction perpendicular to the central axis of the drain trap pipe 12.

[0032] First, as shown in Fig. 4, 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. The right side 38b and the left side 38d are gently inclined inward, and are provided so as to be symmetrical with respect to a line connecting the apex of the upper side 38a and the lowest point of the lower side 38c.

[0033] Next, as shown in FIG. 5, the cross-sectional shape of the inlet portion 40 of the ascending pipe 34 (corresponding to the outlet of the descending pipe 32) is approximately an inverted triangle. The cross-section of the inlet portion 40 has an upper side 40a, a right side 40b, and a left side 40c. Strictly speaking, the right side 40b and the left side 40c are formed in a circular arc shape with a relatively large radius of curvature, but the cross-section of the inlet portion 40 as a whole can be said to be approximately an inverted triangle. In addition, the point where the right side 40b and the left side 40c intersect in the cross-section of the inlet portion 40 corresponds to the lowest point B of the drain trap pipe 12. The cross-section of the inlet portion 40 is provided so as to be symmetrical with respect to the vertical axis passing through the lowest point B. As described above, in this embodiment, the flow passage cross-section at the lowest point B of the ascending pipe 34 is formed in an approximately inverted triangle shape, so that the vector of the flow from the descending pipe 32 to the ascending pipe 34 can be smoothly converted. This allows the wash water to flow into the upflow pipe 34 without significantly losing the energy of the flow forced from the bowl portion 8 into the downflow pipe 32.

[0034] Although not shown, the cross-sectional shape of the descending pipe 32 gradually changes from a substantially square shape to a substantially inverted triangle shape from the inlet 38 to the inlet 40 of the ascending pipe 34 (corresponding to the outlet of the descending pipe 32). In particular, the outlet side 32a (FIG. 2) of the descending pipe 32 has a substantially inverted triangle shape as shown in FIG. 5 in the range of 50 to 100 (or a shorter range including 100) of the descending pipe 32, when the inlet 38 is 0 and the inlet 40 of the ascending pipe 34 is 100. By making the rate of change of the cross-sectional shape of the descending pipe 32 constant, the energy loss caused by the change of the cross-sectional shape can be further suppressed. The rate of change can also be made non-uniform as long as it is within a range in which the energy loss can be suppressed to a certain extent.

[0035] Next, as shown in FIG. 6, the cross-sectional shape of the first cross section 60 of the rising pipe 34 located slightly above the inlet 40 of the rising pipe 34 is approximately pentagonal. The first cross section 60 has 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 oriented in a substantially vertical direction, and the lower right side 60c and the lower left side 60e are oriented obliquely and intersect at the center. Strictly speaking, R is attached to the connection of each side, but the first cross section 60 of the rising 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 a vertical axis passing through the intersection of the lower right side 60c and the lower left side 60e.

[0036] Next, as shown in FIG. 7, the cross-sectional shape of the second cross section 70 of the ascending pipe 34, which is located slightly above the first cross section 60, is approximately pentagonal. The second cross section 70 has 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 oriented in a substantially vertical direction, and the lower right side 70c and the lower left side 70e are oriented obliquely and intersect at the center. Strictly speaking, R is attached to the connection of each side, but the second cross section 70 of the ascending pipe 34 can be said to be approximately pentagonal as a whole. In addition, the radius of curvature of R attached to the connection of each side of the second cross section 70 is larger than that of the first cross section 60. 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 FIG. 8, the third cross section 80 of the ascending pipe 34, which is located slightly above the second cross section 70, has a shape that combines a rectangle and a circular arc. The third cross section 80 has 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 oriented in a substantially vertical direction, and the lower side 80d is formed in a substantially circular arc shape that is convex downward. That is, the radius of curvature of the R portion that connected the lower right side 70c and the lower left side 70e in the second cross section 70 becomes even larger in the third cross section 80, and a single circular arc-shaped lower side 80d is formed.

[0038] Next, as shown in FIG. 9, the cross section 90 of the upper part of the rising pipe 34 is substantially rectangular. The cross section 90 of the upper part of the rising pipe 34 has an upper side 90a, a right side 90b, a left side 90c, and a bottom side 90d, and the upper side 90a is slightly longer in the horizontal 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 downwardly convex arc shape with a very large radius of curvature, but can be considered to be substantially linear. The cross section of the rising pipe 34 is formed in a substantially rectangular shape that is substantially the same as the cross section shown in FIG. 9 over a predetermined section 92 (FIG. 3) that extends from a position slightly above the third cross section 80 toward the downstream side. In this embodiment, the central axis X of the drain trap pipe 12 in the predetermined section 92 is made straight, and this predetermined section 92 extends to the vicinity of the outlet of the rising pipe 34. In this manner, in this embodiment, the central axis X in the predetermined section 92, in which the flow passage cross section is substantially rectangular, is formed substantially linearly, so that clogging of the rising pipe 34 with sewage can be suppressed. Meanwhile, in the section from the cross section 40 of the inlet of the rising pipe 34 to the predetermined section 92, the pipe is curved upward so that the rising pipe 34 faces upward. By changing the cross section of this curved section, the effect of the upward curvature is mitigated, and energy loss can be suppressed.

[0039] Furthermore, in this embodiment, the cross-sectional shape is also substantially rectangular on the downstream side (upper side) of the predetermined section 92, and the cross-section 37 of the outlet of the rising pipe 34 shown in FIG. 10 is also formed in a substantially rectangular shape that is substantially the same as the cross-section 90 of the upper part of the rising pipe 34. That is, the cross-section 37 of the outlet of the rising pipe 34 has an upper side 37a, a right side 37b, a left side 37c, and a bottom side 37d. Here, as shown in FIG. 3, the cross-section 37 of the outlet of the rising pipe 34 includes the highest point T of the drain trap pipe 12. Therefore, the bottom side 37d of the cross-section 37 of the outlet is located at the height of the highest point T and is formed in a substantially horizontal and substantially linear shape. Thus, in this embodiment, the bottom side 37d of the flow path cross-section 37 at the highest point T is formed in a substantially horizontal and substantially linear shape, so that a wide flow path can be secured at the highest point T, and a large amount of flush water and dirt can overcome the highest point T with less energy.

[0040] As shown in Figs. 5 to 10, the cross-sectional shape of the ascending pipe 34 is a substantially inverted triangle (Fig. 5) at the inlet 40 at the upstream end, which maintains continuity with the substantially inverted triangle at the outlet side 32a of the descending pipe 32, and the cross-section on the downstream side gradually becomes closer to a substantially rectangular shape, as shown in Figs. 6, 7, and 8. That is, the flow path cross-sectional shape of the ascending pipe 34 gradually changes from a substantially inverted triangle at the lowest point B to a substantially rectangular shape toward the downstream side. As described above, in this embodiment, the flow path cross-sectional shape of the ascending pipe 34 gradually changes from a substantially inverted triangle at the lowest point B to a substantially rectangular shape, so that the flow resistance when transitioning from the substantially inverted triangular flow path cross-section to the substantially rectangular flow path cross-section can be suppressed, and flush water and waste can be effectively discharged. In addition, in this embodiment, the cross-sectional shape of the ascending pipe 34 is a substantially rectangular shape in the predetermined section 92 (Fig. 3) of the ascending pipe 34 and the entire downstream side thereof. In this manner, in this embodiment, the flow path cross section is formed in a substantially rectangular shape over a predetermined length of the rising pipe 34, so that the flush water flowing upward in the rising pipe 34 can be rectified, energy loss can be suppressed, and the waste discharge speed can be increased. Preferably, the flow path cross section is formed in a substantially rectangular shape over a length of 40% to 60% of the entire length of the rising pipe 34. Also, it is preferable that the section in which the flow path cross section is substantially rectangular is provided in a range from the downstream end (highest point T) of the rising pipe 34 to 40% to 60% of the entire length of the rising pipe 34.

[0041] 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 downflow pipe 32, the maximum height H2 of the cross section perpendicular to the central axis X of the inlet 40 of the upflow pipe 34, the maximum height H3 of the first cross section perpendicular to the central axis X of the upflow pipe 34, the maximum height H4 of the second cross section perpendicular to the central axis X of the upflow pipe 34, the maximum height H5 of the third cross section perpendicular to the central axis X of the upflow pipe 34, the maximum height H6 of the upper cross section perpendicular to the central axis X of the upflow pipe 34, and the maximum height H7 of the outlet cross section perpendicular to the central axis X of the upflow 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.

[0042] 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 rising pipe 34, the maximum width W3 of the first cross section perpendicular to the central axis X of the rising pipe 34, the maximum width W4 of the second cross section perpendicular to the central axis X of the rising pipe 34, the maximum width W5 of the third cross section perpendicular to the central axis X of the rising pipe 34, the maximum width W of the upper cross section perpendicular to the central axis X of the rising pipe 34, and the maximum width W7 of the outlet cross section perpendicular to the central axis X of the rising pipe 34 are all substantially constant. Therefore, the maximum width W of the cross section perpendicular to the central axis X of the rising pipe 34 is substantially constant. In this manner, in this embodiment, the maximum height and maximum width of the flow passage cross section of the rising pipe 34 are formed substantially constant, so that the energy loss of the flow of the cleaning water flowing in the rising pipe 34 can be suppressed. On the other hand, the maximum width W1 of a cross section perpendicular to the central axis X of the inlet portion 38 of the descending pipe 32 is narrower than the maximum width W2 of a cross section perpendicular to the central axis X of the inlet portion 40 of the ascending pipe 34.

[0043] Next, the cross-sectional shape of the inlet portion 40 of the rising 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 rising pipe of the drain trap pipe of a flush toilet according to an embodiment of the present invention. As shown in FIG. 11, the cross-sectional shape of the inlet portion 40 of the ascending pipe 34 is an approximately inverted triangle as described above. This approximately inverted triangle shape will be specifically described. FIG. 11 shows the shape of the inner wall of the inlet portion 40 of the ascending pipe 34. The inlet portion 40 has an approximately triangular cross-sectional shape, which is formed by an upper side 42, a first right side 44, a second right side 46 connected to the first right side 44 by a connecting portion 45, a first left side 48, and a second left side 50 connected to the first left side 48 by a connecting portion 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 approximately arc-shaped.

[0044] The center of the upper side 42 of the inlet portion 40 of the ascending pipe 34 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 the inlet 40 of the rising pipe 34, the height (distance) b from the connecting parts 45, 49 to the lower end 52 is greater than the height (distance) a from the upper end 51 to the connecting parts 45, 49 (i.e., there is a relationship of b>a). The cross-sectional shape of the inlet 40 is provided so as to be symmetrical with respect to the line connecting the upper end 51 and the lower end 52.

[0045] As shown in FIG. 11, the cross section of the inlet portion 40 of the ascending pipe 34 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 second right side edge 46 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 inlet portion 40 of the ascending pipe 34 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).

[0046] 11, in the cross section of the inlet portion 40 of the ascending pipe 34, 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.

[0047] Next, the cross-sectional areas of the inlet 38 and outlet (corresponding to the inlet 40 of the uprising pipe 34) of the descending pipe 32 will be described with reference to Fig. 12. Fig. 12 is a cross-sectional view showing the cross sections of the inlet and outlet of the descending pipe overlapping each other. As shown in Fig. 12, the cross-sectional shape of the inlet 38 of the descending pipe 32 is shown by an imaginary line, and the cross-sectional shape of the outlet is shown by a solid line. Here, the cross-sectional area S1 of the inlet 38 and the cross-sectional area S2 of the outlet are substantially the same. Therefore, the cross-sectional height H1 of the inlet 38 and the cross-sectional height H2 of the outlet are substantially constant, and the cross-sectional area is made substantially constant by making the cross-sectional width W1 of the inlet 38 larger than the cross-sectional width W2 of the outlet (inlet 40 of the ascending pipe 34). In addition, compared to the substantially rectangular inlet 38, the outlet (inlet 40 of the ascending pipe 34) is substantially inverted triangular, and therefore the bottom of the cross section is narrower.

[0048] Next, the cross-sectional area of ​​each portion of the ascending pipe 34 will be described with reference to Fig. 13. Fig. 13 is a cross-sectional view showing the cross sections of the ascending pipe 34 from the inlet 40 to the upper cross section 90, which are overlapped. In Fig. 13, the inlet 40 (Fig. 5) is shown by a thick solid line, the first cross section 60 (Fig. 6) by a dashed line, the second cross section 70 (Fig. 7) by a dashed line, the third cross section 80 (Fig. 8) by a two-dot chain line, and the upper cross section 90 (Fig. 9) by a thin solid line.

[0049] As described above, the maximum heights H2 to H6 of the cross sections from the inlet 40 to the upper cross section 90 of the rising pipe 34 are substantially constant, and the maximum widths W2 to W6 of the cross sections are also substantially constant. Thus, the maximum height and maximum width of each cross section of the rising pipe 34 are substantially constant, while the cross section shape gradually changes from a substantially inverted triangular shape at the inlet 40 to a substantially rectangular shape at the upper cross section 90. Therefore, the cross section of the rising pipe 34 gradually expands from the substantially inverted triangular shape at the inlet 40 to the oblique lower corners on both sides, and the flow path cross-sectional area of ​​the rising pipe 34 increases from the lowest point B to the highest point T. Thus, in this embodiment, the flow path cross-sectional area of ​​the rising pipe 34 increases from the lowest point B to the highest point T, so that the flow velocity of the wash water flowing through the rising pipe 34 can be reduced, and the energy loss of the flow of the wash water can be suppressed.

[0050] In addition, the cross section of the ascending pipe 34 is configured so that the flow path cross-sectional area becomes wider in the lower part from the lowest point B to the highest point T, so that less energy is required to push up the waste with the flushing water. In order to discharge the waste from the ascending pipe 34, it is necessary to push up the waste against gravity, but if the flow path cross-sectional area is narrow in the lower part of the ascending pipe 34, more flushing water and waste must be pushed up to the top in order to discharge the same amount of flushing water and waste. This may increase the energy loss of the flushing water flow. In contrast, in this embodiment, the flow path cross-sectional area of ​​the lower part of the ascending pipe 34 is configured wide, so the amount of waste pushed up to the top of the flow path cross-sectional area is reduced, so energy loss can be suppressed.

[0051] 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 flush toilet 1 according to this embodiment with prior art flush toilets according to Comparative Examples 1 and 2. Fig. 14 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. 15 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. 16 is a partial enlarged diagram of part A of Fig. 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 downflow pipe is approximately rectangular, the cross-sectional shape perpendicular to the central axis at the inlet of the upflow pipe is approximately rectangular, and the cross-sectional shape perpendicular to the central axis at the upper part of the upflow pipe is approximately rectangular. In the flush toilet of Comparative Example 2, the cross-sectional shape perpendicular to the central axis at the inlet of the downflow pipeline is approximately an inverted triangle, the cross-sectional shape perpendicular to the central axis at the inlet of the upflow pipeline is approximately a rectangle, and the cross-sectional shape perpendicular to the central axis at the upper part of the upflow pipeline is approximately a rectangle. In the flush toilet 1 of this embodiment, as described above, the cross-sectional shape perpendicular to the central axis at the inlet of the downflow pipeline is approximately rectangular, the cross-sectional shape perpendicular to the central axis at the inlet of the upflow pipeline is approximately inverted triangular, and the cross-sectional shape perpendicular to the central axis at the upper part of the upflow pipeline is approximately rectangular.

[0053] 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), obtaining the results shown in Figures 15 and 16. First, as shown in FIG. 14, 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).

[0054] Next, as shown in Figures 15 and 16, 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 tail of the water in the bowl. At this time, as shown in Figure 16, 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.

[0055] 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."

[0056] Next, the effects of the flush toilet according to the embodiment of the present invention described above will be explained. According to the flush toilet of the embodiment of the present invention, the cross section of the rising pipe 34 at the lowest point B (cross section at the inlet portion 40 of the rising pipe 34) is formed in a generally inverted triangle shape (FIG. 5), so the vector of the flow from the descending pipe 32 to the rising pipe 34 can be smoothly converted, and flush water can be made to flow into the rising pipe 34 without losing much of the energy of the flow forced from the bowl portion 8 into the descending pipe 32. Also, since the cross section 90 is formed in a generally square shape (FIG. 9) over a predetermined length of the rising pipe 34, the flush water flowing upward in the rising pipe 34 can be rectified, reducing energy loss and increasing the discharge speed of waste. Furthermore, since the base 37d of the cross section 37 at the highest point T is formed in a generally horizontal straight line (FIG. 10), a wide flow path can be secured at the highest point T, and a large amount of flush water and waste can overcome the highest point T with little energy. These actions allow flush water and waste to be effectively discharged.

[0057] Furthermore, according to the flush toilet of this embodiment, the central axis X in the predetermined section 92 of the roughly rectangular cross section (Fig. 9) is formed in a roughly straight line (Fig. 3), which makes it possible to prevent clogging of the rising pipe 34 with waste.

[0058] Furthermore, according to 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 (FIG. 13), so the flow velocity of the flush water flowing inside the rising pipe 34 can be reduced and energy loss in the flow of the flush water can be suppressed.

[0059] Furthermore, according to the flush toilet of this embodiment, the maximum height (H2 to H7) and maximum width (W2 to W7) of the cross section of the rising pipe 34 are formed to be approximately constant (FIG. 13), so energy loss in the flow of flush water through the rising pipe 34 can be suppressed.

[0060] Furthermore, according to the flush toilet of this embodiment, cross section 37 (Figure 10) including highest point T is made approximately rectangular, so that the portion having an approximately rectangular cross section over a certain length can be smoothly connected to the cross section 37 of the outlet at highest point T, where base 37d is approximately horizontal and linear, thereby suppressing disturbance in the flow of flush water.

[0061] Although the embodiment of the present invention has been described above, various modifications can be made to the above-described embodiment. [Explanation of symbols]

[0062] 1 flush toilet 2 Toilet bowl body 8 Bowl section 12 Drain trap line 22 First outlet (outlet) 24 Second outlet (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 Entrance 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 wash-down type flush toilet, 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 riser conduit extends from a lowest point of the drain trap conduit to a highest point defining a water level within the bowl portion; a flush toilet wherein the ascending pipe has a flow path cross section formed in a substantially inverted triangular shape at the lowest point and a substantially rectangular shape over a predetermined length, and the base of the flow path cross section at the highest point is substantially horizontal and substantially straight.

2. 2. A flush toilet as set forth in claim 1, wherein the ascending pipe has a central axis that is formed in a substantially straight line in a predetermined section where the flow path cross section is substantially rectangular.

3. 3. The flush toilet according to claim 1 or 2, wherein the ascending pipe has, in at least a portion thereof, a flow path cross-sectional area which increases from the lowest point to the highest point.

4. 4. The flush toilet according to claim 1, wherein the ascending pipe has a flow path cross-sectional maximum height and maximum width that are substantially constant.

5. 5. The flush toilet according to claim 1, wherein the ascending pipe has a flow path cross section including the highest point that is formed in a substantially rectangular shape.

6. 6. The flush toilet according to claim 1, wherein the rising pipe has a curved portion extending over a predetermined section from the lowest point, and at this curved portion, the flow path cross-sectional shape of the rising pipe gradually changes from a substantially inverted triangular shape at the lowest point to a substantially rectangular shape.

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