DRAINAGE APPARATUS
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to a draining system. More particularly, the present inventio relates to a draining system which is installed in a sewer or a gully hole, one of city basic facilities,, thus easily displacing sewage like waste water, dirty water, rain water, etc. and preventing the sewage and offensive odor from flowing backward as well.
(b) Description of the Related Art
Drainages of kitchen sinks and various industrial facilities or city basic facilities generally have drain pipes or drain traps for displacing sewage such as kitchen slops, industrial waste water, rain water, dirty water, etc. to a sewer or a gully hole. In addition, they have drains that stop sewage or offensive odor from flowing backward as well.
Such a drainer, as depicted in PIGS, 7 and 8, includes a cylindrical pipe 1 that is cylindrical and communicates with the sewer or drainpipe. On the cylindrical pipe I is provided a filter 2 preventing dirt and foreign stuffs from flowing to its main body, A sill 3 is formed around the inner wall of the cylindrical pipe 1 's lower section.
The sill 3 has a lug 4 integrally formed therewith. The lug 4 has a shaft 5 passing through it, On both ends of the shaft 5 is provided a damper 6 pivoting about the shaft 5. A torsion spring 7 is provided to the pipe 1 's inner wall and the damper
6's bottom to give turning force to the damper 6.
According to this conventional drainer, if sewage or wastewater does not enter the pipe 1, the damper 6 is contacting the sill 3 by the torsion spring 7 so that the pipe 1 is being closed. In this way, the drainer stops wastewater or sewage and bad smells from flowing back. If the waste water or sewage flows in the cylindrical pipe 1 through the filter, the damper 6 turns down and opens by hydraulic pressure of the water, thus disposing the waste water to a drainage way. After that, the damper 6 returns to its original position and is closed by the torsion spring 7's elastic force.
However, such a conventional drainer has a lot of problems. First, if the torsion spring 7 was used for a long period of time and loosens or gets rusted, the damper 6 would lose its function, so the sewage or offensive odor can flow backward.
Since opening or closing the damper depends on just the torsion spring's tension, the damper 6 easily slackens or is broken, thus missing the function of the whole drainer. In addition, a seal between the cylindrical pipe and damper is not perfectly kept, and harmful insects can raid to do damage to persons. A pleated pipe that can reduce noises at the time of draining and is easily installed is used as a connection pipe used for the drainer of the kitchen sink.
However, kitchen slops and dirt are left and accumulated on the pleated pipe's inner wall to produce an offensive odor to the interior. This odor does harm to the atmosphere of the kitchen and a room communicating with the kitchen. In order to solve this problem, a sewer lid is employed but it is inconvenient to use.
Additionally, by the back flow of waste water, rain water, etc. during heavy
rain or rainy season houses at a low ground or riverside may be flooded up to floor, which causes losses of lives and fortunes.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a draining system which can easily dispose sewage like waste water, dirty water and rain water through a sewer and prevent the sewage and offensive odor from flowing backward as well.
It is another object of the present invention to provide a draining system which can be correctly opened for smooth disposal of sewage and keep a seal for preventing backflow of the sewage and bad smells even if the draining system is used for a long period of time.
It is still another object of the present invention to provide a draining system which can prevent harmful insects or rats from invading to the interior through a sewer.
It is still another object of the present invention to provide a draining system which can stop dirt or foreign stuffs from laying on the draining system's components and can be used domestically and industrially.
It is still another object of the present invention to provide a draining system which can prevent losses of lives and fortunes of people living at low grounds or riverside due to backflow of sewage, waste water and rain water during heavy rain or rainy season.
In order to achieve the above objects, the present invention provides a draining system including a housing installed on a sewer to communicate with the
sewer, and having a support ring with an opening communicating with the sewer, and a packing installed under the support ring and surrounding the opening; a filter mounted on the upper end of the housing to filter solid stuffs entering the housing, and having a cylindrical guide provided to its central bottom; a shutting member mounted on the guide to be rectilinearly movable so as to be moved down by a hydraulic pressure of sewage if the sewage flows to the housing to open the opening, and moved up after the sewage has been disposed to shut the opening; and a driving unit provided in the shutting member to move the shutting member up and down by the hydraulic pressure and dead weight in response to inflow of the sewage. According to another aspect of the present invention, a draining system includes: a support body provided to a manhole connected to a sewer; a housing detachably inserted in the support body, and having a support ring with an opening communicating with the sewer and a packing provided to the bottom of the support ring and surrounding the opening; a filter mounted on the housing to filter solid stuffs from sewage flowing in the housing, and having a cylindrical guide on its central bottom; a shutting member mounted on the guide to be rectilinearly movable so as to be moved down by a hydraulic pressure of the sewage if the sewage flows to the housing to open the opening, and moved up after the sewage has been disposed to shut the opening, and having a semicircular body detachably contacting the housing's opening, and a center fixing pipe integrally provided to the body and having guide races in which the guide is received; and a driving unit including a driving pipe having a plurality of guide pieces each passing through the shutting member's upper section and each having ends fixed to the guide, and a pair of insertion recesses
oppositely disposed on the driving pipe's lower portion, pinions each rotatably provided in the insertion recesses, a driving column installed in the driving pipe to be movable rectilinearly and having an upper end fixed to the driving pipe's upper end and racks each vertically provided on both sides and in mesh with the pinions, and a weight installed between the center fixing pipe and the driving pipe to make the driving column and the shutting member move up by using dead weight, and having racks each vertically provided in its interior and in mesh with the pinions.
According to another aspect of the present invention, a draining system includes: a support body provided to a manhole connected to a sewer to communicate with the sewer; a housing detachably installed in the support body, and having a support ring with an opening communicating with the sewer, a packing provided to the bottom of the support ring and surrounding the opening, a filter mounted on the housing to filter solid stuffs from sewage flowing in the housing, and a guide on its central bottom; a shutting member mounted on the guide to be rectilinearly movable so as to be moved down by a hydraulic pressure of the sewage if the sewage flows to the housing to open the opening, and moved up after the sewage has been disposed to shut the opening; and a driving unit installed in the shutting member to rectilinearly move the shutting member up and down by the sewage's hydraulic pressure and dead weight in response to inflow of the sewage.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded-perspective view of a draining system according to a first preferred embodiment of the present invention;
FIG. 2 is a sectional view showing a shutting member of FIG. 1 's draining system being closed;
FIG. 3 is a sectional view showing the shutting member of FIG. l's draining system being opened; FIG. 4 is an exploded-perspective view of a draining system according to a second preferred embodiment of the present invention;
FIG. 5 is a sectional view showing the showing a shutting member of FIG. 4's draining system being closed;
FIG. 6 is a sectional view showing the shutting member of FIG. 4's draining system being opened;
FIG. 7 is a perspective view showing the conventional draining system; and
FIG. 8 is a longitudinal-sectional view of FIG. 7's draining system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiments of the present invention are now fully described referring to the attached drawings.
Referring to FIGS. 1 to 3, the first preferred embodiment of the present invention will be described. The draining system of the first preferred embodiment includes a support body 500 fixedly installed to a manhole that is connected to a sewer or gully hole.
Preferably, support body 500 is cylindrical. At least two recesses 510 in I shape are formed on the inside upper wall of support body 500. Recesses 510 each serve to
mate with coupling lugs provided to a housing 100's outer surface (fully described later). The coupling lugs are each removably inserted and settled in recesses 510. On support body 500 is provided a shoulder 520 supporting the housing.
Housing 100 is detachably installed on support body 500. Housing 100 is a short cylindrical tube with opened upper and lower parts. A support ring 110 is formed in housing 100's inside to have a given width for supporting a shutting member (described later). On the outer surface of housing 100 are provided lugs 120 to install housing 100 detachably in support body 500.
As fully depicted in FIG. 2, support ring 110 is formed to slant downward to the middle, and to the middle of support ring 110 is provided an opening 110a through which waste water or sewage is disposed. To the bottom of support ring 110 of housing 100 is attached a round contact packing 111 having a round surface Ilia with the same curvature as that of the shutting member's upper section (described later). This round contact packing 111 removably comes in close contact with the shutting member's upper section to prevent a leakage of offensive odor produced from a sewer. A packing fixing ring 112 is interposed between support ring 110 and round contact packing 111 in order to settle round contact packing 111 in support ring 110 and fill up a gap between them.
As packing 111 is attached to support ring 110's bottom by packing fixing ring 112, round surface Ilia of packing 111 contacts the shutting member's upper section when the shutting member rises, thus keeping a seal between them and preventing bad smells from flowing back. On support ring 110's lower part are formed grooves 110b to firmly join round contact packing 111 to support ring 110.
On the corresponding upper section of packing 111 are provided coupling protrusions 111b to be inserted in grooves 110b. If housing 100 is inserted in housing support body 500, a packing F is preferably provided to keep a seal between them.
A filter 200 is installed on the upper section of housing 100 for filtering wastewater, rainwater, sewage, etc. flowing in housing 100. Preferably, filter 200 is put on housing 100 by being attached to the upper section of housing 100. Filter 200 filtrates solid stuffs mixed in the sewage and bulky somewhat, and has a pair of frames 200a to keep the overall strength. On the center of filter 200, i.e. on the center of each frame 200a is provided a disk 210 having a guide 220 extending downward to lead the shutting member's up and down rectilinear movement. Guide 220 extending downward is in a tube shape. Guide 220 has a race 220a with a spiral line on its inside upper part.
Selectively, a filter cover C is provided on filter 200 to more effectively filter slops and foreign stuffs such as fallen leaves and refuse that can be mixed in the sewage and rain water and introduced to the draining system and to shut housing 100. In housing 100 is installed a shutting member 300 that rectilinearly moves up and down when the sewage, rainwater, etc. are disposed. Shutting member 300 has a semicircular body 301. Body 301 integrally has a center-fixing pipe 350 with guide races 320 along which guide 220 of filter 200 can move rectilinearly. Each of guide races 320 is an inner space of a dual pipe formed by center fixing pipe 350 and protruding pipe 330 that runs out to the inside, spaced a given distance away from center fixing pipe 350's inner wall. A through hole is formed In protruding pipe 330, and on protruding pipe 330 is provided a trap 340 on which a driving unit is
mounted. This trap 340 has a central hole 340a, a plurality of through holes 340b, and a frame 340c.
A driving unit 400 is installed in shutting member 300 to rectilinearly move shutting member 300 up and down. Driving unit 400 includes a driving pipe 410 rectilinearly movable in the through hole of respective center fixing pipe 350 and protruding pipe 330. On the upper part of driving pipe 410 is provided a plurality of guide pieces 411 that are divided from the upper end of driving pipe 410 by a given length and move rectilinearly in guide 220 of filter 200 through trap 340. On the upper portion of respective guide pieces 411 are provided screw threads 411a that mate with race 220a of guide 220 and can be separated from race 220a. A pair of insertion recesses 412 and 412' are oppositely disposed on given points of driving pipe 410's lower portion. Pinions 430 and 430' are each rotatably provided in insertion recesses 412 and 412'. Preferably, on both sides of respective insertion recesses 412 and 412' are provided shaft grooves 412s and 412s' in which shafts of pinions 430 and 430' are each rotatably inserted.
Driving pipe 410 has a driving column 420 that can rectilinearly move in pipe 410. On the upper end of driving column 420 is formed a hole 420a communicating with trap 340's central hole 340a, and driving column 420 is coupled to trap 340 by a fixing means, a bolt B, put in this hole 420a. On both sides of driving column 420, i.e. on points where each correspond to insertion recesses 412 and 412' of driving pipe 410 are vertically provided racks 421 and 421 '. These racks
421 and 421' are respectively in mesh with pinions 430 and 430' of driving pipe 410.
A weight 432 is installed between center fixing pipe 350 and driving pipe
410 to make center fixing pipe 350 and driving pipe 410 move relatively and rectilinearly by using dead weight. Weight 432 includes an outer pipe 440 inserted in center fixing pipe 350 and an inner pipe 450 fixedly mounted in outer pipe 440 and having racks 451 and 451' respectively in mesh with pinions 430 and 430'. Preferably, outer pipe 440 is formed to be a weight such as a copper pipe, and inner pipe 450 with an outer diameter slightly smaller than that of outer pipe 440 is tightly fitted in outer pipe 440 so that it can be moved along with outer pipe 440.
On the lower end of center fixing pipe 350 is provided a shutter 460 to protect various components mounted in center fixing pipe 350 against sewage or wastewater.
Referring now to FIGS. 4 to 6, a second preferred embodiment of the present invention will be fully described.
A draining system of the second preferred embodiment of the present invention includes a support body 600 provided to a sewer or gully hole. Support body 600 has a main cylindrical body 610. To the lower end of support body 600 is integrally provided a support plate 620 that is in a rectangular shape and can be stably mounted on a sewer to be properly used for industrial or city basic facilities. Particularly, support plate 620 facilitates concreting. A pair of lugs 630 are integrally provided to main body 610's inside to removably couple a housing to main body 610. On the upper end of main body 610 of support body 600 is formed a shoulder 640 that serves to support and fix the housing onto support body 600.
Housing 700 is detachably mounted in support body 600. Housing 700 includes a filter 710 on its upper section. Filter 710 has a pair of frames 712 to keep
the strength, and a disk 714 on its middle. This disk 714 includes a guide 720 to lead the up/down rectilinear movement of a shutting member (fully described later). Guide 720 is cylindrical and fixed to the bottom of disk 714 by a bolt 722. On the upper center of guide 720's inside is formed an insertion hole 724 having screw threads. Guide 720 extends downward and is in a tube shape. Housing 700 has a pair of slots 730 on its lower surface to mate with support body 600 's lugs 630, thus detachably fitting housing 700 in main body 610. Preferably, each of slots 730 consists of an entrance 730a into which lug 630 is first inserted vertically, and a guide slot 730b formed transversely from entrance 730a. Housing 700 includes a support ring 740 with a given width to support the shutting member (described later). This support ring 740 slants downward to the middle, as shown in FIG. 5, and has an opening 742 in its middle through which sewage or wastewater is discharged. Under opening 742 of support ring 740, a packing 750 is provided from the bottom to form a seal with the shutting member. A flange 752a inclined downward to the middle is provided to packing 750's through hole 752 which sewage or wastewater is discharged through. Packing 750 is formed of an elastic material such as rubber.
In housing 700 is installed a shutting member 800 moving up and down rectilinearly as sewage or waste water is discharged. Shutting member 800 has a ball- shaped body 810. On the middle of body 810 is provided a guide pipe 820 passing through the whole body 810 and put on guide 720 of housing 700 to be movable rectilinearly. Guide pipe 820 has a sill 822 protruding on a given point of its inner wall, and a packing 824 providing on its upper end for smooth movement of guide
pipe 820 and for forming a seal.
Shutting member 800 includes a recess 830 all around its middle. This recess 830 is formed externally and curved down so that flange 752a of through hole 752 of packing 750 can be detachably received in recess 830. If the inventive draining system with such a recess 830 is provided to a sewer, water is always contained in this recess 830, and as flange 752a of packing 750 is seated in recess 830, thus forming a perfect seal.
Shutting member 800 includes a driving unit 900. Driving unit 900 has a trap 910 fixedly inserted in guide pipe 820 of body 810 of shutting member 800 and guide 720 of housing 700. Trap 910 is formed in a tube shape, and has a central hole 912 on its upper middle, and a frame 916 forming a plurality of through holes 914 in which an end of a driving part (described later) is fixedly inserted. A support sill 918 is formed protruding on the lower part of trap 910's outer surface. Support sill 918 serves to restrict shutting member 800's downward movement, and supports shutting member 800. Trap 910 has a screwy part 920 on its lower part.
A driving pipe 930 is inserted in trap 910 to be movable rectilinearly. Driving pipe 930 is divided to a given length and passes through respective through holes 914 of trap 910. Driving pipe 930 has a plurality of guide pieces 934 which are respectively formed on its divided ends with screw threads 932 and mate with insertion hole 724 of the upper center of guide 720 of housing 700. Driving pipe 930 has a pair of insertion slots 935 and 937 oppositely disposed on its lower part. Pinions 936 and 938 are rotatably inserted in insertion slots 935 and 937. On both sides of respective insertion slots 935 and 937 are provided shaft grooves 935 a and
937a in which shafts of pinions 936 and 938 are each rotatably inserted.
Driving pipe 930 has a driving member or driving column 940 that can rectilinearly move in pipe 930. On the upper end of driving column 940 is formed a hole 942 communicating with trap 910's central hole 912, and driving column 940 is coupled to trap 910 by a fixing means, a bolt 944, that is fitted in hole 942 for fastening. Racks 946 and 948 are vertically provided on both sides of driving column 940, i.e. on points where each correspond to insertion slots 935 and 937 of driving pipe 930. These racks 946 and 948 move respectively in mesh with pinions 936 and 938 of driving pipe 930. A weight 950 is put on driving pipe 930 to make driving pipe 930 move relatively and rectilinearly by using dead weight. Weight 950 includes racks 952 and 954 respectively in mesh with pinions 936 and 938. A lower cap 960 is provided to shut trap 910's lower opening, and assures the field of driving column 940's downward movement. Screw threads 962 are formed in its inside upper section to releasably mate with trap 910's screwy part 920.
The following description is about the assembling method and operation of the draining system of the present invention according to each of the preferred embodiments.
As depicted in FIGS. 2 and 3, as filter 200 is put on the upper opening of housing 100 of the draining system according to the first preferred embodiment of the present invention, guide 220 provided to the bottom of disk 210 is inserted in guide races 320 of shutting member 300. Shutting member 300 is inserted and assembled from the bottom of support ring 110 attached to a given position on
housing 100's inside diameter.
Guide pieces 411 of driving pipe 410 of driving unit 400 are inserted in central hole 340a of trap 340 to be movable rectilinearly. Screw threads 411a, formed on the upper portion of respective guide pieces 411, mate with race 220a of guide 220. Driving column 420 is inserted in driving pipe 410, and pinions 430 and 430' are each inserted in insertion recesses 412 and 412'. Driving pipe 410 is fitted in Inner pipe 450 of weight 432.
Accordingly, racks 421 and 421', formed on both sides of driving column 420, are each in mesh with one side of the respective pinions 430 and 430', and simultaneously with this, racks 451 and 451', provided in inner pipe 450 of weight 432, are each in mesh with the other side of the respective pinions 430 and 430' .
Housing 100 of this assembled body is installed on support body 500 that is mounted in a sewer or a manhole by means of e.g. concrete. Lugs 120 of housing 100 each removably mate with recesses 510 formed on support body 500's inside upper wall.
Referring now to FIG. 2, the operation of the draining system according to the first preferred embodiment of the present invention is described.
If sewage or wastewater does not enter housing 100, weight 432 is being completely placed downward by dead weight. Since the body of shutting member 300 is placed upward, it contacts round contact packing Ill 's round surface Ilia, and opening 110a of housing's support ring 110 is closed, thus keeping the sewage and offensive odor from flowing back.
In this state, the sewage, waste water, rain water, etc. flow into housing
100's inside through filter 200, and are then collected in the upper part of shutting member 300's body 301. If the collected sewage is over a given weight and its hydraulic pressure is higher than weight 432's dead weight, shutting member 300 is moved down by the hydraulic pressure. Accordingly, body 301 of shutting member 300 is separated from contact packing 111, and opening 110a is simultaneously opened so that the sewage is discharged to a sewer through it.
At this point, when respective pinions 430 and 430' of driving unit 400 turn forward as shutting member 300 is moved down, weight 432 is moved up by inner pipe 450, and driving column 420 is being placed down. If the hydraulic pressure against body 301 of shutting member 300 is released as all the sewage is discharged to the sewer, weight 432 is moved down by dead weight. If weight 432 is moved down, inner pipe 450 of weight 432 is also moved down to turn respective pinions 430 and 430' backward so that driving column 420 is moved upward under the control of guide pieces 411 of driving pipe 410.
Simultaneously with driving column 420 's upward movement, shutting member 300 joined to its upper end is also moved up. Body 301 of shutting member 300 finally comes in contact with round surface Ilia of round contact packing 111, thus closing housing 100's opening 110a. Hence, even if the sewage flows back while body 301 of shutting member 300 is completely shutting contact packing 11 l's round surface Ilia surrounding housing 100's opening 110a, body 301 is closely contacting opening 110a of housing 100's support ring 110, thereby keeping the sewage and offensive odor from flowing back.
Since the sewage's weight or hydraulic pressure is relatively higher than weight 432's weight, shutting member 300 is rapidly moved down, and it is slowly moved up by weight 432's weight as the remainder of the waste water is gradually decreased when almost of the water is disposed to the sewer. Referring to FIGS. 5 and 6, the assembling method and operation of the second preferred embodiment of the present invention is fully described as follows.
Guide pipe 820 of the shutting member is put on guide 720 provided to the bottom of disk 714 of housing 700's filter 710 to be movable rectilinearly. Guide pipe 820 encloses guide 720 through support ring 740 of housing 700. Guide pieces 934 of driving pipe 930 of the driving unit are fitted in respective through holes 914 of trap 910 to be removable rectilinearly. Screw threads 932 each formed on the upper ends of guide pieces 934 mate with insertion hole 724 of guide 720 of housing 700. Prior to that, driving column 940 is inserted in driving pipe 930, and a pair of insertion slots 935 and 937 of driving pipe 930, oppositely disposed on its lower part, receive pinions 936 and 938, respectively. Driving pipe 930 is inserted in weight 950.
Each of racks 946 and 948 provided to both sides of driving column 940 is in mesh with one side of respective pinions 936 and 938, and simultaneously with this, each of racks 952 and 954 formed in weight 950 is in mesh with the other side of respective pinions 936 and 938. Housing 700, shutting member 800 and driving unit 900 are completely assembled by screwing trap 910 to lower cap 960. Such a housing 700 is joined to support body 600 installed in a sewer or gully hole by concrete. If turning housing 700 in one direction while support body 600 's lugs 630 are respectively inserted in
entrances 730a of a pair of slots 730 formed on the lower surface of housing 700, lugs 630 of support body 600 are each positioned on the vertical ends of guide slots 730b so that housing 700 is detachably installed in support body 600.
The following description is about the operation of the draining system according to the second preferred embodiment of the present invention.
As depicted in FIG. 5, weight 950 is being positioned completely down while sewage or wastewater does not flow in housing 700. Relatively, opening 742 of support ring 740 is closed by body 810 that is moved completely upward. Flange 752a of packing 750 surrounding opening 742 of support ring 740 is inserted in recess 830 of body 810, and water is contained in recess 830 of body 810, thus keeping the sewage and offensive odor from flowing back.
Waste water, sewage, rain water, etc. flow to housing 700 's inside through filter 710 and are collected on body 810 of shutting member 800. If the collected sewage is over a given weight and its hydraulic pressure is higher than weight 950's dead weight, shutting member 800 is moved down by the hydraulic pressure. Accordingly, body 810 is separated from packing 750 and opening 742 of support ring 740 is opened, and the sewage is discharged to a sewer.
As shutting member 800 is moved down to turn respective pinions 936 and 938 of driving unit 900 forward, weight 950 is moved up by the interaction between racks 952 and 954 and each of pinions 936 and 938, and driving column 930 is being placed down.
At this point, if all the sewage or rainwater is discharged to the sewer to remove the hydraulic pressure against body 810, weight 950 is moved down by dead
weight. As weight 950 is moved down, each rack 952 and 954 of weight 950 is turned backward, and respective guide pieces 934 of driving pipe 930 are moved up under the guidance of trap 910's through holes 914. As driving column 940 is moved up, trap 910 coupled to driving column 940 is moved up, and shutting member 800 mounted on trap 910 is moved up simultaneously.
As body 810 comes in contact with packing 750's through hole 752 finally, opening 742 of housing 700 is closed. Particularly, by inserting flange 752a of packing 750 surrounding opening 742 in recess 830 of body 810, opening 742 is perfectly closed. Even if the sewage flows back or adverse pressure is produced, packing 750's flange 752a is tightly fitted in recess 830 of body 810 by such a hydraulic pressure or atmospheric pressure, and the remainder of the sewage in recess 830 prevents the sewage and bad smells from flowing back.
Since the sewage's weight or hydraulic pressure is relatively higher than weight 950's weight, shutting member 800 is rapidly moved down, and it is slowly moved up by weight 950's weight as the remainder of the waste water is gradually decreased when almost of the water is disposed to the sewer.
The interior is perfectly isolated from the sewer and closed except the time of discharging rain water, sewage, etc., which prevents the sewage and bad smells from flowing back and also stops harmful insects such as mosquitoes from intruding into the interior through the sewer.
The inventive draining system can easily dispose sewage, dirty water, rain water, etc. through a sewer, and perfectly keeps the sewage and offensive odor from flowing back as well, thus increasing the reliability.