JP3535922B2 - Suction tube tip structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tip structure of a suction pipe, and more specifically, it is submerged in a water pool of a vacuum type sewage collection system, and the water in the water pool is sucked by opening a vacuum valve. The present invention relates to the tip structure of a suction pipe configured to suck a gas-liquid mixed fluid of water and air.

[0002]

2. Description of the Related Art As a tip structure of a suction pipe of this type, a technique described in Japanese Utility Model Laid-Open No. 4-61186 has been conventionally known. This tip structure of the suction pipe has a function of preventing the tip opening of the suction pipe from being blocked by foreign matter.
However,. By opening the vacuum valve, the suction order holding function that first sucks the water in the water pool and then sucks the gas-liquid mixed fluid of water and air halfway ,. Suction gas-liquid ratio holding function that totally sets the volume ratio of the suction amounts of water and air to approximately water 1: air 3 (atmospheric pressure conversion). From the start of suction of the gas-liquid mixed fluid to the end of suction, it does not have a suction gas-liquid ratio variation function of gradually increasing the suction amount of air with respect to the suction amount of water.
Therefore, a large amount of air will be sucked in after the suction of water is completed, and the water downflow pipe (sewage downflow pipe) connected to the vacuum valve mass where the vacuum valve is installed becomes negative pressure. Negative pressure is applied to the trap upstream of the water inflow pipe (for example, a trap in the toilet) to damage the trap, or because the vacuum valve closing timing is a little earlier, the vacuum valve is sucking only water. When the valve is closed, the water on the downstream side of the vacuum valve temporarily moves in the downstream direction due to inertia, and then is pulled back to the vacuum valve side to give an impact to the vacuum valve, that is, a water hammer may occur. ing.

On the other hand, there is a suction tube tip structure described in JP-A-6-117013. However, this tip structure of the suction pipe does not have the above-mentioned functions and, and also does not have a function of preventing the tip of the suction pipe from being blocked by foreign matter. Moreover, since an intake pipe for simultaneously sucking in water and air is required, the number of parts is increased, and foreign matter is easily entangled inside and outside the intake pipe to reduce the amount of air suctioned and cleaning for removal of entangled foreign matter. It has drawbacks such as high frequency.

[0004]

That is, the conventional suction pipe tip structure does not have a suction rank holding function, a suction gas-liquid ratio holding function, and a suction gas-liquid ratio changing function, and also has a suction tube tip. Is blocked by foreign matter and requires an intake pipe, which increases the number of parts, and foreign matter is easily entangled inside and outside the intake pipe, reducing the air intake amount and increasing the frequency of cleaning to remove foreign matter that has become entangled. It has drawbacks such as Therefore, the invention according to claim 1 has a suction rank holding function, a suction gas-liquid ratio holding function, and a suction gas-liquid ratio varying function, and even if the tip of the suction pipe is blocked by foreign matter, water and air Suction pipe that avoids the increase in the number of parts by eliminating the need for a separate intake pipe, and avoids the inconveniences such as a decrease in the amount of air suction that occurs due to the use of the intake pipe and frequent cleaning of foreign matter removal. The purpose is to provide the tip structure of the. According to the second aspect of the present invention, the suction of the gas-liquid mixed fluid is started at an appropriate timing so that the total volume ratio of the suction amounts of water (liquid) and air can be set to a predetermined ratio.

[0005]

The invention according to claim 1 is
It is connected to the upstream side of the valve and submerged in the water pool, and when the water level in this water pool rises to the suction start water level, the valve is opened and the suction force of the suction means connected to the downstream side of the valve It is a tip structure of a suction pipe that sucks water in the water pool portion and sucks a gas-liquid mixed fluid of water and air from the middle, penetrating a peripheral wall of the suction pipe and upward from a tip opening of the suction pipe. A slit extending toward the middle of the suction start water level is formed.
According to the invention of claim 1, only the water in the water pool is sucked in while the water level in the water pool drops from the suction start water level to the upper end of the slit, and gas-liquid mixing is performed as the water level drops from the upper end of the slit. Inhale fluid. The suction gas-liquid ratio at the time of sucking the gas-liquid mixed fluid changes as the water level decreases from the upper end of the slit to the tip opening of the suction pipe. That is, as the water level decreases from the upper end of the slit to the tip opening of the suction pipe, the exposed area on the water surface of the slit increases,
The ratio of the intake amount of air gradually increases. Further, even if the tip of the suction pipe is blocked by a foreign matter, it is possible to continue sucking water and air through the slit. Furthermore, even if foreign matter is caught in the slit, the lower end of the slit is open, so when the water level drops to the tip opening of the suction pipe, the foreign matter is taken up on the water surface, so the foreign matter will not block the slit. Can be avoided. The invention according to claim 2 is
The slit height of the slit from the tip opening to the upper end of the suction pipe is set to a range of 2/3 to 1/4 of the height from the tip opening to the suction start water level, and the slit width dimension. Is 1 / of the total circumference of the peripheral wall of the suction pipe tip
It is characterized in that it is set in the range of 24 to 1/12. According to the invention of claim 2, by starting the suction of the gas-liquid mixed fluid at an appropriate timing,
The total volume ratio of the suction amounts of water and air can be set to a predetermined ratio.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, the suction pipe 3 on the upstream side of the vacuum valve 2 installed in the vacuum valve mass 1 is submerged in the water reservoir 4, and the outlet of the outflow pipe 5 on the downstream side of the vacuum valve 2 is equipped with a vacuum pump 6. It opens at the sewage collection site 7. The vacuum valve 2 opens when the water level in the water pool portion 4 rises to the suction start water level HWL and the pressure in the water level detection pipe 8 reaches the upper limit set value, and the water level in the water pool portion 4 rises. By lowering to the level LWL of the tip opening 3B of No. 3, the valve is closed when the pressure in the water level detection pipe 8 drops to the lower limit set value.

As shown in FIGS. 2 and 3, the suction pipe 3 is formed with a slit 9 penetrating the peripheral wall 3A and extending from the tip end opening 3B of the suction pipe 3 upward along the axial line to the middle. There is. The range of the cut height h and the width dimension W from the tip opening 3B of the slit 9 to the upper end is set vacuum degree,
This is for adjusting the amount of air suction by the shape of the water pool portion 4, and the cutting height h is in the range of 2/3 to 1/4 of the height H from the tip opening 3B of the suction pipe 3 to the suction start water level HWL ( The width dimension W of the slit 9 is preferably set to about 1/2) and the distal end peripheral wall 3A of the suction pipe 3 is
Is set within a range of 1/24 (internal angle of 15 degrees) to 1/12 (internal angle of 30 degrees). In addition, 10 in the figure shows a sewage downflow pipe.

With such a construction, while the vacuum valve 2 is opened, only the water in the water pool 4 is sucked in while the water level in the water pool 4 is lowered from the suction start water level HWL to the upper end of the slit 9. The gas-liquid mixed fluid can be sucked as it goes down from the upper end of the slit 9. That is, the suction rank holding function is exerted. Further, the cutting height h of the slit 9 is set to the suction start water level HW from the tip end opening 3B of the suction pipe 3.
The height W up to L is set to about 1/2, and the width dimension W of the slit 9 is set to 1 of the total circumferential length of the tip peripheral wall 3A in the suction pipe 3.
By setting / 24 to 1/12, the total volume ratio of the suction amounts of water and air is set to water 1: air 3
The function of holding the suction gas-liquid ratio set to (atmospheric pressure conversion) can be exhibited. Moreover, the suction gas-liquid ratio at the time of sucking the gas-liquid mixed fluid changes as the water level decreases from the upper end of the slit 9 to the tip opening 3B of the suction pipe 3. Specifically, as the water level decreases from the upper end of the slit 9 to the tip opening 3B of the suction pipe 3, the exposed surface area of the slit 9 on the water surface increases, and the ratio of the air suction amount gradually increases. That is,
At the time of suction of the gas-liquid mixed fluid, the suction gas-liquid ratio varying function of gradually increasing the suction amount of air with respect to the suction amount of water is exhibited.

As a result, a state in which a large amount of air is sucked in after the suction of water is completed does not occur, so that the sewage downflow pipe 10 is negatively pressured and the trap provided upstream of the sewage downflow pipe 10 is damaged. Does not happen. Further, even if the valve closing timing of the vacuum valve 2 is slightly advanced, the vacuum valve 2 is closed while the gas-liquid mixed fluid is being sucked in, so that the inside of the outflow pipe 5 on the downstream side of the vacuum valve 2 is closed. The gas-liquid mixed fluid of
Even if the vacuum valve 2 is moved back to the vacuum valve 2 side due to inertia when the valve is closed, the expansion time of the air component delays the pullback time, and the contraction of the air component reduces the impact on the vacuum valve 2. Water hammer can be prevented.

On the other hand, even if the tip opening 3B of the suction pipe 3 is blocked by a foreign matter, the suction of water and air can be continued through the slit 9. Further, even if foreign matter is caught in the slit 9, the lower end of the slit 9 is open, and therefore, when the water level drops to the level LWL of the tip opening 3B of the suction pipe 3, the foreign matter is taken into the water surface. Therefore, the slit 9 can be prevented from being blocked by foreign matter. Moreover, since the conventionally used intake pipe is not required, the number of parts can be reduced, and the occurrence of inconveniences such as a decrease in the amount of air intake due to entanglement of foreign matter and a high frequency of cleaning to remove entangled foreign matter are avoided. it can.

According to an experiment, the cutting height h of the slit 9 is such that the suction start water level HWL from the tip opening 3B of the suction pipe 3.
If it exceeds ⅔ of the height H, the suction start timing of the gas-liquid mixed fluid becomes too early and the suction amount of sewage is reduced, and the water level in the water pool 4 is changed to the level LWL of the tip opening 3B of the suction pipe 3. It has been confirmed that the total suction volume ratio of air becomes too large as the time to decrease to h becomes longer, and if h is smaller than 1/4 of H,
It has been confirmed that the suction start timing of the gas-liquid mixed fluid is delayed, the suction volume ratio of air becomes too small, and the suction amount of air is insufficient, and the width dimension W of the slit 9 is the tip portion of the suction pipe 3. 1/12 of the total circumference of the peripheral wall 3A
It has been confirmed that when it exceeds, the suction amount of air at the time of suction of the gas-liquid mixed fluid becomes excessive and prevents the water level in the water pool portion 4 from being lowered. Furthermore, it was confirmed that if the width dimension W of the slit 9 is relatively smaller than the above-mentioned 1/24, the amount of air sucked in at the time of sucking the gas-liquid mixed fluid becomes insufficient and the degree of entanglement of foreign matters increases. There is.

[0012]

As described above, according to the first aspect of the invention, only the water is sucked in while the water level in the water pool is lowered from the suction start water level to the upper end of the slit, and the water level is lowered from the upper end of the slit. Along with this, the suction rank holding function of sucking the gas-liquid mixed fluid can be exhibited, and the slit can perform the suction gas-liquid ratio holding function of setting the volume ratio of the suction amount of water to the desired value and the water level. As the water drops from the upper end of the slit to the tip opening of the suction pipe, the suction gas-liquid ratio variation function that gradually increases the air suction amount with respect to the water suction amount can be exhibited, so that the water suction is completed. It is possible to prevent the inconvenience caused by sucking a large amount of air later, and to prevent the water hammer that has occurred when the valve closing timing of the vacuum valve is a little earlier. That. In addition, even if the tip opening of the suction pipe is blocked by a foreign substance, the suction of water and air can be continued from the slit, and even if a foreign substance is caught in the slit, the lower end of the slit is open, so the water level The foreign matter can be taken into the water surface at a time point when the pressure has decreased to the level of the tip opening of the suction pipe 3, and the slit can be prevented from being blocked by the foreign matter. Moreover, since the conventionally used intake pipe is not required, the number of parts can be reduced, and the occurrence of inconveniences such as a decrease in the amount of air intake due to entanglement of foreign matter and a high frequency of cleaning to remove entangled foreign matter are avoided. You can also do it. According to the second aspect of the present invention, the total volume ratio of the suction amounts of water and air can be set to a predetermined ratio by starting the suction of the gas-liquid mixed fluid at an appropriate timing.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a suction pipe.

FIG. 3 is a view on arrow AA in FIG.

[Explanation of symbols]

2 Vacuum valve (valve) 3 suction pipe 3A Perimeter wall of suction pipe 3B Suction tube tip opening 4 water pool 6 Vacuum pump (suction means) 9 slits H Height from the tip opening of the suction pipe to the suction start water level h Cut height of slit Width of W slit HWL suction start water level

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F04D 7/04 E03F 1/00 E03F 3/02 E03F 5/22 E03F 7/00

Claims (2)

(57) [Claims] 1. A suction connected to the upstream side of the valve, which is connected to the upstream side of the valve and submerged in a water pool, and when the water level in the water pool rises to the suction start water level, the valve is opened and the downstream side of the valve is connected. The suction pipe is configured to suck the water in the water pool by the suction force of the means, and to suck the gas-liquid mixed fluid of water and air from the middle of the suction pipe, and the suction pipe penetrating the peripheral wall of the suction pipe. A front end structure of a suction pipe, wherein a slit extending upward from a front end opening to a midpoint of the suction start water level is formed. 2. The cutting height from the tip opening to the upper end of the suction pipe of the slit is set in the range of 2/3 to 1/4 of the height from the tip opening to the suction start water level, The tip portion structure of the suction pipe according to claim 1, wherein the width dimension of the slit is set in the range of 1/24 to 1/12 of the entire circumferential length of the peripheral wall of the suction pipe tip portion.