CN104264772B - Rain water collecting system initial Split-flow device - Google Patents

Rain water collecting system initial Split-flow device Download PDF

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Publication number
CN104264772B
CN104264772B CN201410569952.5A CN201410569952A CN104264772B CN 104264772 B CN104264772 B CN 104264772B CN 201410569952 A CN201410569952 A CN 201410569952A CN 104264772 B CN104264772 B CN 104264772B
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flow
guiding channel
abandoned stream
conducting element
locating part
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CN201410569952.5A
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CN104264772A (en
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郭家龙
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Dezhou Lvqiu Plastic Industry Co ltd
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02ATECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00Water conservation; Efficient water supply; Efficient water use
    • Y02A20/108Rainwater harvesting

Abstract

The invention discloses a kind of rain water collecting system initial Split-flow device, including housing, intake tunnel and the abandoned stream passage mutually separated and exhalant canal, conducting element and tumbler, the first locating part and the second locating part it is provided with in housing, there is on intake tunnel drain gully, conducting element is positioned at the lower section of drain gully, conducting element is provided with flow-guiding channel, one end of flow-guiding channel is positioned at the top of abandoned stream passage, the other end of flow-guiding channel is positioned at the top of exhalant canal, and tumbler connects conducting element and makes conducting element around the axis rotation being positioned in the middle part of flow-guiding channel;It is inclined to abandoned stream passage end that first locating part limits flow-guiding channel, and it is inclined to exhalant canal one end that the second locating part limits flow-guiding channel, and under normality, flow-guiding channel is inclined to abandoned stream passage end.The present invention has the advantages such as idle, not electricity consumption, unpowered, maintenance cost is low, abandoned stream is effective.

Description

Rain water collecting system initial Split-flow device
Technical field
The present invention relates to a kind of rain water collecting system, be specifically related to a kind of rain water collecting system initial Split-flow device.
Background technology
The abandoned stream that rain water collecting system initial Split-flow device of the prior art generally uses the structure such as electromagnetic valve, ball float to realize early-stage rainwater, structure is complicated, needs electric power, and maintenance cost is high.
Summary of the invention
It is contemplated that at least solve one of technical problem present in prior art.
The technical solution adopted for the present invention to solve the technical problems is:
A kind of rain water collecting system initial Split-flow device, including housing, intake tunnel and the abandoned stream passage mutually separated and exhalant canal, conducting element and tumbler it is provided with in described housing, first locating part and the second locating part, on described intake tunnel, there is drain gully, described conducting element is positioned at the lower section of described drain gully, conducting element is provided with flow-guiding channel, one end of described flow-guiding channel is positioned at the top of described abandoned stream passage, the other end of described flow-guiding channel is positioned at the top of described exhalant canal, described tumbler connects described conducting element and makes described conducting element around the axis rotation being positioned in the middle part of described flow-guiding channel;It is inclined to abandoned stream passage end that described first locating part limits described flow-guiding channel, and it is inclined to exhalant canal one end that described second locating part limits described flow-guiding channel, and under normality, described flow-guiding channel is inclined to abandoned stream passage end.
Wherein referring under normality when not collecting rainwater, the axle center rotated relative to it, conducting element is positioned at the quality of abandoned stream passage end and is more than the quality being positioned at exhalant canal one end, thus flow-guiding channel tilts to left end under normal conditions.
It addition, rain water collecting system initial Split-flow device according to embodiments of the present invention can also have a following additional technical feature:
Preferably, described intake tunnel have level or towards the described flow-guiding channel shock surface near one end of described exit passageway.It can thus be appreciated that, at Rainwater Initial, amount of rainfall is less, and rainwater near vertical at drain gully falls, incline direction along flow-guiding channel flows out to abandoned stream passage end, when amount of rainfall is bigger, rainwater with speed faster through shock surface, then when drain gully falls, parabolically shape falls, the other end of flow-guiding channel is had percussion, and conducting element tilts towards exhalant canal one end under impact force action, and then realizes rainwater-collecting.Further, described drain gully is positioned at the described flow-guiding channel top near one end of abandoned stream passage, so can avoid just having started amount of rainfall during rainfall relatively big, cause conducting element to overturn, it is impossible to realize abandoned stream.
Preferably, described conducting element includes deflector and is positioned at the baffle plate of deflector both sides, deflector and baffle plate and surrounds described flow-guiding channel.It follows that described deflector has smooth guide face, baffle plate has the effect preventing rainwater from spilling to both sides.
Preferably, described tumbler includes bearing pin and the bearing cooperated, and described bearing pin is connected to the middle part of described conducting element.It follows that by bearing pin and bearing make conducting element can around bearing pin formed axle center freely rotatable.
Preferably, described first locating part and the second locating part are respectively provided at the lower section at described flow-guiding channel two ends.
Preferably, the bottom in described housing is provided with dividing plate, and the lower part of described housing is divided into two parts by described dividing plate, and these two parts are respectively communicated with described abandoned stream passage and exhalant canal.
Preferably, being provided with support in described housing, described support is provided with cross bar, and cross bar is positioned at the described flow-guiding channel lower section near described abandoned stream passage end, forms described first locating part;The upper end of described dividing plate extends to the described flow-guiding channel lower section near one end of described exit passageway, and the upper end of described dividing plate forms described second locating part.Further, described tumbler includes bearing pin and the bearing cooperated, and described bearing pin is connected to the middle part of described conducting element, and described bearing sets on the bracket.
Preferably, in described housing, the inner side of exhalant canal is provided with filter screen.
Preferably, being provided with lid at described drain gully, described lid is connected with described intake tunnel by hinge.
Preferably, the top of described housing is provided with manhole cover.
The present invention carries out abandoned stream or the collection of rainwater according to the size of amount of rainfall during rainwater-collecting, the most less in rainwater-collecting early-stage rainwater amount, the impulsive force of rainwater is less, drop under normality on the flow-guiding channel that abandoned stream passage end tilts through the rainwater of drain gully, rainwater flows to abandoned stream passage, it is achieved the abandoned stream of rainwater.When after the initial stage, rainwater quantitative change is big, and impulsive force also becomes big, and conducting element is freely rotatable around axle center under the impact force action of rainwater, tilts to exhalant canal one end, and rainwater then flows out from exhalant canal, it is achieved the collection of rainwater.When rainy end, amount of rainfall diminishes to stopping, and conducting element turns to tilt to abandoned stream passage end.
It follows that the rain water collecting system initial Split-flow device of the present invention has the advantages such as idle, not electricity consumption, unpowered, maintenance cost is low, abandoned stream is effective.
Accompanying drawing explanation
Fig. 1 is the perspective view of the rain water collecting system initial Split-flow device of the present invention;
Fig. 2 is the sectional view of the rain water collecting system initial Split-flow device of the present invention.
Wherein: 1 housing;2 intake tunnels;3 abandoned stream passages;4 exhalant canals;5 first locating parts;6 second locating parts;7 water inlets;8 drain gullies;9 shock surfaces;10 abandoned stream mouths;11 outlets;12 deflectors;13 baffle plates;14 bearings;15 supports;16 dividing plates;17 lids;18 filter screens.
Detailed description of the invention
The present invention will be described below in conjunction with the accompanying drawings, and is only used for explaining the present invention, and is not considered as limiting the invention.
As shown in Figure 1-2, a kind of rain water collecting system initial Split-flow device, for collecting the rainwater of roof or road surface, it includes housing 1, intake tunnel 2 and the abandoned stream passage 3 mutually separated and exhalant canal 4, is provided with conducting element and tumbler, the first locating part 5 and the second locating part 6 in housing 1.
Its middle shell 1 is bottom closure, the cylindrical shape of upper cover gab made with the steel plate that 0.8cm is thick, is provided with manhole cover at upper end open.Intake tunnel 2(includes inlet channel), abandoned stream passage 3(include abandoned stream pipeline) and exhalant canal 4(include outlet conduit) all levels are located on housing 1.Intake tunnel 2, abandoned stream passage 3 and exhalant canal 4 are the tubular that the steel plate of 1mm is made.Intake tunnel 2 horizontally extends in housing 1, a diameter of 300mm, and the left end of intake tunnel 2 is water inlet 7, is used for connecting rainwater collection collector, and right-hand member is drain gully 8.It is 300mm that intake tunnel 2 is positioned at the partial-length outside housing 1, and the partial-length being positioned at housing 1 is 200mm.Abandoned stream passage 3 and intake tunnel 2 are positioned at same one end of housing 1, and its left end is abandoned stream mouth 10, and abandoned stream mouth 10 is used for connecting sewer pipe.The right-hand member of abandoned stream passage 3 is connected on housing 1, a diameter of 200mm, a length of 300mm.Exhalant canal 4 is located at the other end of intake tunnel 2, a diameter of 300mm, a length of 200mm, and the left end of exhalant canal 4 is connected on housing 1, and right-hand member is outlet 11, and outlet 11 is used for connecting rainwater collection pool.Outer twice paint of the side brush (red) of this device entirety, as rust preventing.
Being provided with lid 17 at described drain gully 8, described lid 17 is connected with described intake tunnel 2 by hinge.Intake tunnel 2 has the shock surface 9 of level, i.e. lower surface within intake tunnel 2.At Rainwater Initial, amount of rainfall is less, rainwater near vertical at drain gully 8 falls, and the incline direction along flow-guiding channel flows out to abandoned stream passage 3 one end, when amount of rainfall is bigger, rainwater with speed faster through shock surface 9, again when drain gully 8 falls, parabolically shape falls, and the other end of flow-guiding channel is had percussion, conducting element tilts towards exhalant canal 4 one end under impact force action, and then realizes rainwater-collecting.
Bottom in housing 1 is provided with dividing plate 16, the lower part of housing 1 is divided into two parts by dividing plate 16, these two parts are respectively communicated with abandoned stream passage 3 and exhalant canal 4, namely two parts that the lower part of housing 1 is divided into by dividing plate 16 are abandoned stream passage 3 and a part for exhalant canal 4 respectively.In housing 1, middle part is provided with the support 15 of I-shaped, and including the cross bar between two poles being attached in parallel on housing 1 inwall and two poles, cross bar is positioned at the flow-guiding channel lower section near abandoned stream passage 3 one end, forms described first locating part 5.The upper end of described dividing plate 16 extends to the flow-guiding channel lower section near one end of exit passageway, and the upper end of dividing plate 16 forms described second locating part 6.It is inclined to abandoned stream passage 3 one end that first locating part 5 limits flow-guiding channel, it is inclined to exhalant canal 4 one end that second locating part 6 limits flow-guiding channel, i.e. when conducting element extremely contacts with the first locating part 5 around described axis rotation, flow-guiding channel is inclined to abandoned stream passage 3 one end, when conducting element extremely contacts with the second locating part 6 around described axis rotation, flow-guiding channel is inclined to exhalant canal 4 one end.Under normal conditions, flow-guiding channel is inclined to abandoned stream passage 3 one end.
Described conducting element includes deflector 12 and is positioned at the baffle plate 13 of deflector 12 both sides, and deflector 12 and baffle plate 13 surround flow-guiding channel.Tumbler includes the bearing 14 at bearing pin and the bearing pin two ends cooperated, bearing pin is connected to the middle part of conducting element, vertical with the direction of flow-guiding channel, by bearing pin and bearing 14 make conducting element can around bearing pin formed axle center freely rotatable, so that flow-guiding channel is around this axis rotation.Two bearings 14 are respectively provided on two poles of described support 15, and the width of deflector 12 is less than the distance between two poles.Flow-guiding channel one end is positioned at the top of abandoned stream passage 3, and the other end of flow-guiding channel is positioned at the top of exhalant canal 4.
Wherein referring under normality when not collecting rainwater, the axle center rotated relative to it, conducting element is positioned at the quality of abandoned stream passage 3 one end and is more than the quality being positioned at exhalant canal 4 one end, thus flow-guiding channel tilts to left end under normal conditions.
The inner side being positioned at exhalant canal 2 in housing 1 is provided with filter screen 18, can play the effect of further impurity screening.
The rain water collecting system initial Split-flow device of the present embodiment can be embedded in underground, connects rainwater collection collector, sewer pipe and rainwater collection pool.The most less in rainwater-collecting early-stage rainwater amount, the impulsive force of rainwater is less, drops under normality on the flow-guiding channel that abandoned stream passage 3 one end tilts through the rainwater of drain gully 8, and rainwater flows to abandoned stream passage 3, it is achieved the abandoned stream of rainwater.When after the initial stage, rainwater quantitative change is big, and impulsive force also becomes big, and conducting element is freely rotatable around axle center under the impact force action of rainwater, tilts to exhalant canal 4 one end, and rainwater then flows out from exhalant canal 4, it is achieved the collection of rainwater.When rainy end, amount of rainfall diminishes to stopping, and conducting element turns to tilt to abandoned stream passage 3 one end.
The rain water collecting system initial Split-flow device of the present invention has the advantages such as idle, not electricity consumption, unpowered, maintenance cost is low, abandoned stream is effective.
Although the detailed description of the invention of the present invention is described by the above-mentioned accompanying drawing that combines; but not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme, those skilled in the art need not to pay various amendments or deformation that creative work can make still within protection scope of the present invention.

Claims (8)

1. a rain water collecting system initial Split-flow device, it is characterized in that, including housing, intake tunnel and the abandoned stream passage mutually separated and exhalant canal, conducting element and tumbler it is provided with in described housing, first locating part and the second locating part, on described intake tunnel, there is drain gully, described conducting element is positioned at the lower section of described drain gully, conducting element is provided with flow-guiding channel, one end of described flow-guiding channel is positioned at the top of described abandoned stream passage, the other end of described flow-guiding channel is positioned at the top of described exhalant canal, described tumbler connects described conducting element and makes described conducting element around the axis rotation being positioned in the middle part of described flow-guiding channel;It is inclined to abandoned stream passage end that described first locating part limits described flow-guiding channel, it is inclined to exhalant canal one end that described second locating part limits described flow-guiding channel, under normality, described flow-guiding channel is inclined to abandoned stream passage end, and conducting element is positioned at the quality of abandoned stream passage end more than the quality being positioned at exhalant canal one end;Bottom in described housing is provided with dividing plate, and the lower part of described housing is divided into two parts by described dividing plate, and these two parts are respectively communicated with described abandoned stream passage and exhalant canal;Being provided with support in described housing, described support is provided with cross bar, and cross bar is positioned at the described flow-guiding channel lower section near described abandoned stream passage end, forms described first locating part;The upper end of described dividing plate extends to the described flow-guiding channel lower section near one end of described exit passageway, and the upper end of described dividing plate forms described second locating part.
Rain water collecting system initial Split-flow device the most according to claim 1, it is characterised in that described intake tunnel have level or towards the described flow-guiding channel shock surface near one end of described exit passageway.
Rain water collecting system initial Split-flow device the most according to claim 1, it is characterised in that described drain gully is positioned at the described flow-guiding channel top near one end of abandoned stream passage.
Rain water collecting system initial Split-flow device the most according to claim 1, it is characterised in that described conducting element includes deflector and is positioned at the baffle plate of deflector both sides, deflector and baffle plate and surrounds described flow-guiding channel.
Rain water collecting system initial Split-flow device the most according to claim 1, it is characterised in that described tumbler includes bearing pin and the bearing cooperated, described bearing pin is connected to the middle part of described conducting element.
Rain water collecting system initial Split-flow device the most according to claim 1, it is characterised in that described first locating part and the second locating part are respectively provided at the lower section at described flow-guiding channel two ends.
Rain water collecting system initial Split-flow device the most according to claim 1, it is characterised in that in described housing, the inner side of exhalant canal is provided with filter screen.
Rain water collecting system initial Split-flow device the most according to claim 1, it is characterised in that the top of described housing is provided with manhole cover.
CN201410569952.5A 2014-10-23 2014-10-23 Rain water collecting system initial Split-flow device Active CN104264772B (en)

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Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104863248A (en) * 2015-05-13 2015-08-26 中国灌溉排水发展中心 Sewage collecting device
CN105178414B (en) * 2015-08-28 2017-01-04 武汉金牛经济发展有限公司 A kind of rainwater flow-discarding device
CN105386502A (en) * 2015-11-09 2016-03-09 无锡市三六九钢管有限公司 Sewer pipe capable of collecting solid garbage
CN105888037A (en) * 2016-04-06 2016-08-24 重庆大学 Rainwater drop discarding water collecting device
CN105863031A (en) * 2016-04-06 2016-08-17 重庆大学 Efficient rainwater hydraulic drop discarding water collecting device
CN105926755B (en) * 2016-04-25 2019-11-15 泰兴市东城水处理工程有限公司 Rain water drainage cuts dirty well
CN106677316B (en) * 2017-03-14 2023-07-21 重庆大学 Tipping bucket type initial rainwater discarding device
CN108018936B (en) * 2017-12-13 2020-11-13 大连理创科技有限公司 A inlet for stom water for rainwater is retrieved and is recycled
CN110331759B (en) * 2019-07-19 2021-03-09 常州碧瑞达水处理科技有限公司 Secondary rainwater recovery device with sand and dust pre-separation rainwater collecting nozzle

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102505753A (en) * 2011-11-08 2012-06-20 扬州大学 Turning plate type preliminary rainwater intercepting well

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3602592A1 (en) * 1986-01-29 1987-07-30 Rolf Stahn Process and apparatus for reducing peak discharges in rainwater lines or combined-sewage lines
KR100781790B1 (en) * 2006-07-19 2007-12-04 이경우 Apparatus for discharging sewage with combined sewer overflow
CN202039413U (en) * 2011-01-24 2011-11-16 陈柏臻 Tipping bucket type clean rainwater collector
CN203307912U (en) * 2012-09-28 2013-11-27 李红伟 Flow distribution type automatic rainwater split-flow device
CN203782853U (en) * 2014-04-29 2014-08-20 合肥工业大学 Hydrodynamic self-control initial rainwater abandoning device
CN204112464U (en) * 2014-10-23 2015-01-21 郭家龙 Rain water collecting system initial Split-flow device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102505753A (en) * 2011-11-08 2012-06-20 扬州大学 Turning plate type preliminary rainwater intercepting well

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Effective date of registration: 20190402

Address after: No. 56 Apple Garden Road, Tianqu Industrial Park, Dezhou City, Shandong Province, 253027

Patentee after: DEZHOU LVQIU PLASTIC INDUSTRY CO.,LTD.

Address before: 250023 Room 402, Unit 2, Building No. 93, East Street, Huaiyin District, Jinan City, Shandong Province

Patentee before: Guo Jialong

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Denomination of invention: Initial waste water device of rainwater collection system

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Pledgee: Dezhou Lingcheng Rural Commercial Bank Co.,Ltd.

Pledgor: DEZHOU LVQIU PLASTIC INDUSTRY CO.,LTD.

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Denomination of invention: Initial disposal device for rainwater collection system

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