EP1992747A2

EP1992747A2 - Overflow pit with adjustable channel

Info

Publication number: EP1992747A2
Application number: EP08425284A
Authority: EP
Inventors: Nicola Ravanini
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-04-24
Filing date: 2008-04-23
Publication date: 2008-11-19
Also published as: EP1992747A3; ITMN20070018A1

Abstract

The present invention relates to an overflow pit with adjustable channel indicated for obtaining an accurate calculation of the flow rate which is exceeded and for decreasing energy losses.

The pit is constituted of an external structure (2) made of concrete or plastic, with an essentially parallelepiped or cylindrical configuration, with a trapdoor whose covering function is envisaged to allow access to the inside of the pit. The structure (2) features an inlet opening (3) envisaged to house one end of an inlet conduit (30), a first outlet hole (4) envisaged to house one end of an overflow conduit (40) and a second hole (5) envisaged to house one end of an outlet conduit (50) in which the opening (3) and the first hole (4) feature runoff surfaces at the same height, while the second hole (5) is housed below the first hole (4), a chute (6) is located between the opening (3) and the second hole (5) and envisaged to mutually connect, in a uniform fashion, the opening (3) and the second hole (5). The structure comprises, in particular, a connection between the opening (3) and the first hole (4) obtained by means of a channel (7), which is essentially composed of a blade (70) and a couple of lateral walls (71) laid out in a mutually parallel fashion, a couple of containment bulkheads (9), laid out in a mutually parallel fashion and externally to the lateral walls (71), a shaped collar (10) located in proximity to the opening (3), immediately after the inlet conduit (30) and adjustment elements which adjust the channel (7) to reduce the rate of the flow which runs from the inlet conduit to the outlet conduit through the chute (6) and allow the blade (70) to be raised or lowered, varying its position according to the rate of the flow that has to reach the outlet conduit and the rate of the flow that has to reach the overflow conduit.

Description

The present invention relates to an overflow pit with adjustable channel particularly indicated for obtaining an accurate calculation of the flow rate which is exceeded and for decreasing energy losses.
As is known, in sewerage conduits, using overflow pits, there is a need to remove, or in any case separate, a part of the water from waste water canalisation. This water contains the waste from various human activities or from working activities, such as agriculture and industry. This waste contains organic and inorganic substances which, if left to run into natural environments without any appropriate and prior cleaning treatment, result in varying degrees of contamination, with consequences for the flora, fauna and humans.
Similarly, too, meteoric water must be separated into early and late stormwater, which is why, in the canalisation that collect the rain water, overflow pits are used, which are designed to separate the water flows. At present, the overflow pits are realised by means of an article made of cement or plastic with a generally parallelepipedic or cylindrical configuration, endowed with a first opening to house an inlet conduit and second opening for an outlet conduit which features the same flow surface as the inlet conduit. Furthermore, the pit features a third conduit, called the overflow conduit, which is generally located at a higher level with respect to the previous conduits and calculated by the engineer according to the necessities of the mains located upstream of the article.
In addition to the pit illustrated previously, a further type of overflow pit is employed, which features three conduits all located on the same flow surface, but the overflow conduit is separated from the others by a small wall (known as the overflow sill), which only allows the water to flow over when the mains inlet and outlet level has reached the top of the sill.
While the said overflow pits do fulfil their task, several problems and drawbacks have emerged therefrom.
A first drawback is derived from the fact that there is a certain inconsistency between the exceeded flow rate calculated on paper and the actual overflow rate, as a uniform water motion is envisaged which is not created in reality. Furthermore, there are energy losses due to sudden rises and irregularities in the bottom because of the presence of residues and, in particular, the sudden widening or narrowing of the section of the pit's inlet/outlet opening. These losses lead, initially to a decrease in the hydraulic height in the pit, but subsequently to a rise in level before the restriction caused by the outlet conduit.
In addition, a further problem arises when the small wall which constitutes the sill is present, as there are energy losses around the wall too. Everything illustrated previously leads, in consequence, to a difficulty in calculating the flow rate in the conduit and in the pit, with the final consequence being that it proves extremely complicated to accurately calculate the actual flow rate exceeded.
These situations involve conduits and pits which are not accurately scaled and, consequently, mains that function badly, with consequent leaks and the presence of inappropriate substances contained in waste water in sections of the conduit envisaged as immune from the said substances.
A further drawback arising from the presence of the overflow sill is that the article thus realised (in the event that the conditions of the relative basin change upstream thereof) would need to be destroyed completely, or, in more fortunate cases, solely the overflow sill would need to be destroyed, and
another one created, at a higher, more adequate level.
The aim of the present invention is essentially to resolve the problems of the commonly known technique, overcoming the drawbacks by means of an overflow pit with adjustable channel able to obtain an accurate calculation of the flow rate which is exceeded.
A second aim of the present invention is to have an overflow pit with adjustable channel able to decrease energy losses.
A third aim of the present invention is to have an overflow pit with adjustable channel which allows adjustment later on if the conditions of the relative basin upstream of the article change.
A further aim of the present invention is to have an overflow pit with adjustable channel which allows the flow rate to be exceeded to be set, without having to destroy or rebuild the article or part thereof.
A still further aim of the present invention derives from the fact that the overflow pit with adjustable channel allows the channel to be removed simply if removal of the overflow is rendered necessary and allows the article to be converted into a manhole.
A further but not final aim of the present invention is to realise an overflow pit with adjustable channel which is easy to manufacture and works well.
These aims and others besides, which will better emerge over the course of the present description, are essentially achieved by means of an overflow pit with adjustable channel, as outlined in the claims below.
Further characteristics and advantages will better emerge in the detailed description of an overflow pit with adjustable channel according to this invention, provided in the form of a non-limiting example, with reference to the accompanying drawings, in which

figure 1 shows, schematically and from a perspective view, an overflow pit with adjustable channel as per the present invention;
figure 2 shows, schematically and from a further perspective view, the overflow pit in figure 1;
figure 3 shows, schematically and from a perspective view, a detail of the overflow pit in question.
figure 4 shows a section view and an exploded view of the overflow pit in figure 1;
figure 5 shows an overhead view and an exploded view of the overflow pit according to the present invention.

With reference to the aforesaid figures, and in particular figure 1, 1 denotes an overflow pit with adjustable channel as a whole, according to the present invention.
The overflow pit 1 in question is suitable to be employed in the sewerage mains to mutually connect sections of piping separating certain flows of water which run through it and convey it in different conduits.
Pit 1 features an external structure 2 with an essentially commonly known structure, i.e. parallelepipedic or cylindrical, with a trapdoor whose covering function is envisaged to allow access to the pit. Structure 2 is realised, preferably, with concrete or plastic.
In more detail, external structure 2 comprises an inlet opening 3 envisaged to house one end of an inlet conduit 30, a first outlet hole 4 envisaged to house one end of an overflow conduit 40, and a second hole 5 envisaged to house one end of an outlet conduit 50, as clearly shown in figure 4.
In particular, opening 3 and first hole 4 feature a flow surface at the same height, while second hole 5 is housed below first hole 4.
According to the present embodiment, between opening 3 and second hole 5, the pit comprises a chute 6 designed to mutually connect, in a uniform fashion, opening 3 and hole 5.
Furthermore, the connection between opening 3 and first hole 4 is obtained by means of a channel 7 which is essentially composed of a blade 70 and a couple of lateral walls 71 laid out in a mutually parallel fashion, as shown in figure 3. In more detail, each lateral wall features a trapezoidal configuration with a first side 71 a, which is sloping, while the other side, 71b, is arched. Furthermore, channel 7 is engaged in a rotary manner, at point 8, in proximity to first hole 4, as shown in figure 4.
In accordance with the present invention, pit 1 is equipped with a couple of containment bulkheads 9, laid out in a mutually parallel fashion and externally to lateral walls 71 on the same side as wall 71 a. As illustrated in figures 1 and 2, each containment bulkhead features an L-shaped configuration, in which the smaller arm of the "L" is fixed to the internal wall of structure 2, above the second hole 5 and laterally in relation to first hole 4.
In addition to everything illustrated so far, the pit comprises a shaped collar 10, located in proximity to opening 3, immediately after inlet conduit 30. Shaped collar 10 features lateral walls 11, on the side facing the interior of the pit, equipped with an arched profile 11 a, which proves complementary to the shape of side 71b of channel 7. Profile 11 allows the channel to move and slide, reducing to a minimum lateral leaks of the fluid running through the channel. Furthermore, shaped collar 10 features a base 12 and an upper side 13 parallel to the base, which have a profile 12a/13a which allows them to rest on the internal contour of structure 2. As illustrated in figure 5, external structure 2 features a cylindrical configuration, therefore profile 12a/13a is arched in order to follow the curve of the internal wall of structure 2. In particular, when structure 2 is parallelepipedic, profile 12a/13a is linear.
In the present embodiment, channel 7, containment bulkheads 9 and shaped collar 10 are preferably realised with stainless steel to provide excellence resistance to corrosion by substances running through the pit, but can be realised with other materials as long as they match the described characteristics.
In addition to everything illustrated above, channel 7 can be appropriately adjusted, thus reducing the rate of the flow which runs from the inlet conduit to the outlet conduit through the chute. In fact, channel 7 can be raised or lowered and therefore it is possible to vary its position according to the flow rate wanted at the outlet conduit and the flow rate wanted at the overflow conduit.
In the present embodiment, the position of the channel is adjusted by means of adjustment elements. In more detail, the adjustment elements are constituted of a chain or bolts. When the position of channel 7 is obtained by means of a chain, the latter features one end secured, preferably, to lateral wall 71 and the other end to the trapdoor of structure 2.
In the event that the position of the channel is, on the other hand, fixed by means of bolts, these are located in such as way as to restrain, by pressure, the movement of the lateral wall and are housed on the containment bulkheads. In addition, the movement of the channel can be impaired by securing each of the lateral walls of the channel with lateral wall 11 of the collar by means of one or more small bored bars fixed with screws or bolts.
Next to the channel there is a graphical indicator which allows the position of the channel to be known with respect to base 12 of the collar against the containment bulkheads and therefore opening 3.
Channel 7, should it be necessary, can be ballasted with suitable weights located, for example, externally to lateral walls 71, to resist the incoming hydraulic thrust at the article.
The channel can be adjusted by a system of floats which impose, in this way, a self-adjustment system.
In addition to everything illustrated so far, and in accordance with the present invention, inside the pit other conduits may converge, in addition to the inlet conduit.
After the predominantly structural description above, the operation of the invention in question will now be outlined.
The rate of the flow that comes from inlet conduit 30 enters the pit through opening 3 and runs towards the bottom of the pit, transiting over chute 6 and reaching second hole 5, with minimum dissipation of the flow speed.
As the flow rate increases in the inlet conduit, the hydraulic level rises until it reaches the height of blade 70 in the channel, which cuts off the fluid, separating the two rates of flow: one continues along the pit bottom from second hole 5 into outlet conduit 50 and the other, running along the channel, reaches first hole 4 and runs into overflow conduit 40.
If the incoming hydraulic thrust at the article is particularly strong, channel 7 can be ballasted with suitable weights in order to resist the force exerted by the incoming fluid.
As mentioned earlier, the position of the channel is fixed by means of specific adjustment screws or a fastening chain to be anchored to the trapdoor of the article's external structure.
To find out the position of the channel, one can simply read what is displayed on the graphical indicator located beside the channel, which shows the height at which the blade is located with respect to the sliding of opening 3.
When it is necessary to alter the outlet rate of the flow running to one or the other conduit, the position of the channel and the height at which blade 70 is positioned can simply be adjusted.
Thus the present invention achieves the aims set.
The overflow pit with adjustable channel in question offers the possibility of a more accurate calculation of the flow rate which is exceeded, as the channel blade makes it possible to set the preferred actual flow rate to be exceeded according to the degree of fullness of the inlet conduit.
Advantageously, with the overflow pit with adjustable channel according to the present invention, the energy losses due to either a decrease in the flow speed or the presence of obstacles which alter the level of the flow are decreased as the unions are made more evenly, without sudden decreases or increases in the section.
Furthermore, the article will be adjustable later on if the conditions of the relative basin upstream of the article should change, without having to carry out work or alterations to the mains, as occurs with the commonly know technique. In addition, it will also be possible to adjust the position of the channel to set the flow rate to exceed, without having to destroy anything.
A further advantage that emerges from the overflow pit with adjustable channel is the fact that, if removal of the overflow is necessary, it is possible to remove, quite simply, the channel and bulkheads. Furthermore, by cementing the connecting chute between opening 3 and second hole, it is possible to convert the article into a manhole which connects the inlet conduit with the overflow conduit.
A further but not final advantage of the present invention is that it proves remarkable easy to use and to manufacture and works well.
Naturally, further modifications or variants may be applied to the present invention while remaining within the scope of the invention that characterises it.

Claims

An overflow pit with adjustable channel of the type comprising an external structure (2) made of concrete or plastic, with an essentially parallelepipedic or cylindrical configuration, with a trapdoor whose covering function is envisaged to allow access to the inside of the pit, characterised by the fact that the said structure (2) features:
- an intake opening (3) envisaged to house one end of an inlet conduit (30), a first outlet hole (4) envisaged to house one end of an overflow conduit (40), and a second hole (5) envisaged to house one end of an outlet conduit (50), and the said opening (3) and the said first hole (4) feature flow surfaces at the same height, while the second hole (5) is housed below the first hole (4);

- a chute (6) between the said opening (3) and the said second hole (5), designed to mutually connect, in a uniform fashion, the said opening (3) and the said hole (5);

- a connection between the said opening (3) and the said first hole (4), obtained by means of a channel (7), which is essentially composed of a blade (70) and a couple of lateral walls (71) laid out in a mutually parallel fashion and realised with stainless steel;

- a couple of containment bulkheads (9), laid out in a mutually parallel fashion and externally to lateral walls (71) and realised with stainless steel;

- a shaped collar (10) realised with stainless steel and located in proximity to the opening (3), immediately after the inlet conduit (30),

- adjustment elements which adjust the said channel (7) to reduce the rate of the flow running from the inlet conduit to the outlet conduit through the chute (6) and allow the blade (70) to be raised or lowered, varying its position according to the rate of the flow that has to reach the outlet conduit and the rate of the flow that has to reach the overflow conduit.
An overflow pit with adjustable channel according to claim 1, characterised by the fact that each lateral wall (71) features a trapezoidal configuration with a first side (71a) which is sloping, while the other side (71b) is arched.
An overflow pit with adjustable channel according to claim 1, characterised by the fact that the said channel (7) is engaged in a rotary manner at point (8), in proximity to the first hole (4).
An overflow pit with adjustable channel according to claim 1, characterised by the fact each containment bulkhead (9) is located on the same side as side 71a and features an L-shaped configuration, in which the smaller arm of the "L" is fixed to the internal wall of the structure (2), above the second hole (5) and laterally in relation to the first hole (4).
An overflow pit with adjustable channel according to claim 1, characterised by the fact that the said shaped collar (10) features lateral walls (11), on the side facing the interior of the pit, equipped with an arched profile (11a) which proves complementary to the shape of the side (71b) of the channel (7) to allow the channel to move and slide, reducing to a minimum lateral leaks of the fluid running therethrough.
An overflow pit with adjustable channel according to claim 1, characterised by the fact that the said shaped collar (10) features a base (12) and an upper side (13) parallel to the base, which have a profile (12a)/(13a) which allows them to rest on the internal contour of the structure (2).
An overflow pit with adjustable channel according to claim 6, characterised by the fact that the said profile (12a/13a) is arched when the external structure (2) features a cylindrical configuration, while it is linear when the structure (2)is parallelepipedic.
An overflow pit with adjustable channel according to claim 1, characterised by the fact the said adjustment elements are constituted of a chain which features one end secured, preferably, to the lateral wall (71) and the other end to the trapdoor of the structure (2) or bolts which are located in such as way as to restrain, by pressure, the movement of the lateral wall and are housed on the containment bulkheads.
An overflow pit with adjustable channel according to claim 1, characterised by the fact the said the said adjustment elements which restrain the movement of the channel comprise one or more small bored bars fixed with screws or bolts which mutually engage each of the lateral walls of the channel with lateral wall (11) of the collar.
An overflow pit with adjustable channel according to claim 1, characterised by the fact that, next to the channel there is a graphical indicator which allows the position of the channel to be known with respect to base (12) of the collar against the containment bulkheads and therefore the opening (3).
An overflow pit with adjustable channel according to claim 1, characterised by the fact the said channel (7) can be ballasted with suitable weights located externally to lateral walls (71) to resist the incoming hydraulic thrust at the article and can be adjusted by a system of floats which constitute a self-adjustment system.