AU8100487A - Flushing arrangement - Google Patents

Description

Flushing arrangement

This invention relates to a flushing arrangement for quick and automatic emptying of a water container upon filling thereof to a certain maximum level, comprising a tube assembly designed to operate as a siphon during emptying, and being pivotable abou a horizontal axis as well as being adapted to be elevated by buoyancy in the water during filling of the container up to the maximum level.

Such a flushing arrangement or siphon operates to the effec that during a short time period it empties it accumulated water or liquid contents to a channel or conduit downstream of the flushing arrangement, in order to flush and distribute liquid an solid substances in the conduit. Flushing arrangements of the type concerned here are in particular employed in connection wit waste water, sewage and the like, in which the contents of pollution and solid substances can involve serious problems because of the tendency to deposits and clogging.

There are many previously known designs of flushing arrange ments or siphons for use in waste water conduits and for water distribution. In order to attain the desired effect many of the known arrangements are designed with a tube assembly being fixedly mounted in a container, and there are often involved one or more narrow passages and movable, fine calibre tubes. Moreover, there have been provided emergency overflows which enter into function by clogging, which in turn prevents a complete emptying of the magazine or container and removal of possible bottom sludge. The suction tube end is located above the bottom of the container of the flushing arrangement.

These known designs are relatively delicate, and completely fail in their function under certain conditions, in particular i the rising rate of the water or liquid filling in the container is low, when the siphon lock of the flushing arrangement has dried out or by clogging of fine calibre tubes and channels as mentioned above.

A known design which in the principle generally corresponds to what is stated in the introduction above, is described in US Patent 2.487.022. According thereto the necessary buoyancy for the siphon device is provided for by a pivotable, separate float body being adapted to be filled with liquid when the maximum level has been reached. The disadvantage of this known design, specifically is found therein that the pivotable float body constitutes a movable part which in polluted liquid will be subject to problems because of solid substances and the like, which can be detrimental to the movable mechanism. Therefore the operation reliability under difficult conditions will be low. The design described in the US patent possibly may only have a satisfactory function when operating with completely clean water.

Other examples of previously known designs based upon a siphon effect and movement of the siphon device brought about by buoyancy in the water or liquid during filling of the container, may be found in US patents 2.090.551 and 2.965.122. Also these arrangements have corresponding disadvantages as the design according to the above discussed US patent.

According to the present invention there is obtained an improved flushing arrangement based upon a siphon device in the form of a tube assembly, whereby the novel and specific features mainly consist therein that the buoyancy is provided for by the tube assembly itself, since portions thereof being incorporated in the water flow path during emptying, during elevation are adapted to contain air which gives the necessary buoyancy until the whole tube assembly is filled with water for initiating emptying by siphon effect.

Quite generally the solution according to the invention makes the flushing arrangement tolerate unfavourable operating conditions and therefore is very reliable in operation. This ne flushing arangment is working well after having been dried out, by entering of sludge and and by water rising rates being low or zero, and besides upon attempt of clogging. The new structure is also independent of any auxiliary water supply for its function. The field of use of this flushing arrangement thus may be extended to comprise also water containing sludge and sewage.

The advantages obtained are related to the employment of a tube assembly which does not involve narrow channels or movable fine calbre tubes. In a flushing arrangement according to the invention the tube assembly can consist of continuous tube portions having comparatively large cross-sectional dimensions, which possibly can be more or less constant along the whole length of the tube assembly which constitutes the siphon device. Taking as a starting point a situation in which the contai¬ ner of the flushing arrangement has just been emptied, the operation thereof in short is as follows:

Initially the tube assembly forms a powerful float body which gives a large buoyancy in the water and is elevated until the desired or predetermined water level is attained in the contain¬ er. During this the tube assembly will be filled with water either by assuming an altered angle with respect to the water surface or thereby that in a certain position the tube assembly is arrested against further rising movement and the water over¬ pressure is high enough to fill the complete tube assembly and t remove the counterpressure from a possible siphon lock. Thereby the water-filled tube assembly quickly sinks towards the bottom of the container and forms a secure siphon connection. This leads to the emptying of the container. At the termination of the emptying interval air can be gradually supplied to the sipho or tube assembly in the flushing arrangement during the termina¬ ting phase of the emptying. This means that the complete container volume can be utilised at the next flushing.

The tube assembly is connected through a flexible coupling and articulation to an output conduit or channel which leads out of the flushing arrangement to a following conduit system or the like. In order to completely empty the container in some instances with a low water head, there must be mounted a siphon lock downstream of the flushing arrangement so as to prevent entry of air from the following conduit.

The invention as well as additional specific features and advantages thereof, shall be explained more closely in the following description with reference to the drawings, in which: Fig. 1 shows a schematic vertical and longitudinal section through a flushing arrangement according to the invention, with the tube assembly in its lowered and emptied position, Fig. 2 shows in a corresponding manner the flushing arrange- ment with the tube assembly in a maximum elevated position, during filling thereof with water, and Fig. 3 also shows the flushing arrangement in a corresponding manner, but with the completely water-filled tube assembly in its lowered position during emptying of th container contents.

In fig.l there is shown a container 1 with an inlet 3 and a outlet at 4 through a siphon lock 5 and at 6 a connection to a following conduit or channel system. At the bottom 2 of the container there is indicated a rest 21 of water or liquid after more or less complete emptying of the contents of the container, the tube assembly 10 which constitutes the siphon device being i its fully lowered position in fig.l. The tube assembly or sipho device 10 in this embodiment is formed by a continuous length of tubes being composed of various portions or parts for the purpos of providing the desired buoyancy effect when the water or liqui level in the container 1 again commences to rise. At 11 in fig.l. ther is shown a flexible coupling or articulation between the outlet 4 and an elongate tube portion 12 which in the position shown in fig.l, lies substantially horizontally, but anyhow with a certain small inclination towards the outlet 4. The tube portion 12 extends generally from one end to the other of the container 1 and continues through a U-shaped tube member 13 backwards as a tube portion 14 which leads to a bend and an upward portion 16 with an uppper U-shaped tube portion 17 which finally continues in a downward member 18 having an open mouth a 19. The whole tube assembly with the designated portions 12, 13 14, 16, 17 and 18 advantageously can have the same flow cross- sectional area, which can have large dimensions in view of a desired capacity as well as solid substances or the like which may occur. It may be an advantage however, to have the actual mouth cross-sectional area at 19 somewhat reduced in relation to the mentioned tube cross-sectional area in the rest of the system, in order that larger objects or clods and the like canno enter the tube assembly and lead to clogging therein. It will b seen from fig.l the mouth 19 is so arranged that it will be positioned far down towards the bottom 2 of the container when the tube assembly is in its lower position. A resilient abuttin element 15, for example made of rubber, can be provided at the bottom 2 as to determine a well defined lower position of the tube assembly 10. Moreover, in the figures of drawings there is indicated a certain inclination of the bottom 1 towards a deeper middle portion underneath the mouth 19.

With the illustrated design of the tube assembly 10 it will be realised that when the container 1 has been emptied by siphon effect through the tube assembly 10, this whole tube assembly will be empty as far as water or liquid is concerned, i.e. it is filled with air. Therefore, when the water level in the contai¬ ner 1 commences to rise by supply of water through the inlet 3 , the air which will be enclosed in the tube assembly 10, will result in a strong buoyancy effect which causes the tube assembl to be gradually elevated or swung up to an upper position as shown in fig.2, whereby the flexible coupling at 11 can be considered to form a horizontal pivot axis as shown at 31 in fig.2. Although some water will gradually enter through the mouth 19 and the downward tube portion 18, the substantial portion of the buoyant air will be present in the tube assembly all the time until the upper position as shown in fig.2 has been reached. Further elevation of the tube assembly 10 may possibly be prevented by means of a stop as indicated at 39. In this angular position (angle V as shown in fig.2) the overflow threshold formed at 13' and 17' respectively, in the two U- shaped portions 13 and 17, will lie approximately at the same level close up to the water level as indicated at 22 in the container 1 in fig.2, which makes it possible for water to enter the whole tube assembly and fill this substantially completely. The weight of the tube assembly itself and the buoyancy relation¬ ships should be adjusted so that the tube assembly does not start to sink before it has been filled with water to a sufficient degree for the desired siphon effect to be safely established. It will be understood that with a design based on a continuous flow path or tube structure as shown in the drawing, the geome¬ trical relationships are very significant for an effective utilisation of the whole container volume. Thus, it is signifi¬ cant that the upwardly projecting U-portion 17 has an appropriat- ely selected height in order thereby to secure the buoyancy effect and a sufficiently elevated overflow threshold as indica¬ ted at 17* in fig.2, at the same time as this point must have a proper relationship to the overflow in U-portion 13, as these point together with the pivot point 31 essentially determine the maximum water level 22 which implies the initiation of the siphon effect in the container. For an effective utilisation of the container volume this maximum level 22 should of course be located high up towards the top of the container.

In the situation illustrated in fig.2 water is penetrating into the tube assembly, whereby water from tube portion 18 rising and running over at the threshold 17' , will gradually fill the tube portions 16 and 14 upwards from the bend between these portions, with water surfaces as indicated at 32 and 33 respec¬ tively. While this filling of the tube assembly proceeds, there will be present air filled compartments at 34 and 35 respective¬ ly,^' which provide for buoyancy. At a certain stage during the filling, these buoyancy compartments will become so small that sufficient buoyancy is no longer existing and the tube assembly will suddenly sink as the whole assembly will then also be filled with water and forms an effective siphon.

An attempt to present the above discussed geometrical relationships somewhat more concretely, but anyhow in an approxi¬ mate manner, has been made in fig.3, in which the tube assembly 10 similar to the position in fig.l, has been shown fully lowered. In fig.3 it is assumed that the emptying of the water in the container 1 is still going on, and the level can be as indicated at 23. The tube assembly itself has also been shown with a complete filling of water, which can contain air or gas bubbles as indicated. The abutting element 15 is shown somewhat compressed under the weight of the filled tube assembly.

In fig.3 there are shown important magnitudes or dimensions as follows: L is the length of the horizontal tube portion 12 measured from the articulation or pivot point ^'31, H is the vertical distance from the horizontal tube portion 12 to the highest overflow point 17' in the inverted U-shaped portion 17, and D is the maximum water head in the container 1 measured from the horizontal tube portion 12.

Based upon the above definitions, which can be regarded as approximate and not fully accurate, the design shown in the drawings will have an advantageous effect as discussed above, when the relative dimensions satisfy the following mathematical expression: |H² + F² H«L/D

This relationship is provided by simple geometrical considera¬ tions and deductions based on the position taken by the tube assembly in fig.2, in consideration of the dimension statements or definitons appearing from fig.3. In this connection it is preferred according to the invention that the maximum angular movement which is represented by the angle V in fig.2, between the lowered position and the maximum elevated position, is approximately equal to 30°.

From what is described here it appears that the siphon device or tube assembly 10 which during the filling stage forms buoyant or float body, immediately changes its character after having been filled with water when the desired emptying or flushing level of water in the container 1 has been reached. Then the tube assembly sinks so as to establish thereupon a safe siphon connection which is not broken until the container is empty, and possibly a new siphon lock is established when the tube mouth 19 slowly has started to suck in false air, and the tube assembly 10 again has been transformed into a float body having buoyancy as described.

The embodiment of the tube assembly 10 which has been shown and described with reference to the figures of drawings, represents an example of the essential structure of such an assembly according to the invention, but it will be realised tha many modifications are possible within the scope of the inven¬ tion. For example, instead of consisting of a single continuous length of tubing or flow path, the tube assembly possibly in par can consist of two or more branches in parallel, depending among other things on the space conditions and necessary dimensions in order to obtain a sufficient capacity in the individual installa tions. The design however will become particularly simple and reliable when the tube assembly is composed of tube portions having the same cross-sectional dimensions along the whole flow path through the tube assembly. Also the illustrated design wit U-tube portions having a certain minimum radius of cvurvature, i advantageous for a reliable and secure effect throughout long periods of operation and with water or liquid having more or les significant proportions of solid substances or particles, object or clods therein.

Claims (11)

C L A I M S

1. Flushing arrangement for quick and automatic emptying of a water container (1) upon filling thereof to a certain maximum level (22), comprising a tube assembly (10) designed so as to operate as a siphon during emptying, and arranged to be pivotabl about a horizontal axis (31) as well as adapted to be elevated b buoyancy in the water during filling of the container up to the maximum level (22), characterized in that the buoyancy is provided for by the tube assembly (10) itself, whereby portions thereof being incorporated in the water flow path during empty¬ ing, during the elevating stage are adapted to contain air (34, 35) which gives the necessary buoyancy until the whole tube assembly is filled with water for initiating the emptying by siphon effect.

2. Flushing arrangement according to claim 1, characterized in that said portions of the tube assembly (10) comprise an inverte U-shaped tube portion (17) which by lowered tube assembly (fig.3 is located higher than all other parts thereof.

3. Flushing arrangement according to claim 2, characterized in that the tube assembly (10) in addition to the inverted U-shaped portion (17) comprises other tube portions (12 - 14) which by lowered tube assembly.lie mainly horizontally, preferably with a certain inclination in the direction towards an outlet (4) to a following discharge channel or conduit (5, 6) .

4. Flushing arrangement according to claim 2 or 3 , characte¬ rized in that the tube assembly (10) is pivotable about an articulation or pivot point (31) near the bottom (2) of the container (1), preferably formed by a flexible or bellows-like tube piece (11) at the outlet (4) from the container.

5. Flushing arrangement according to claim 3 or 4, characteri¬ zed in that said other tube portions (12 - 14) most remote from the outlet (4) is formed with a lying U-tube member (13).

6. Flushing arrangement according to claim 3, 4 or 5, characte rized in that the relative dimensions thereof considered in the lowered position, is approximately determined by "JH² + F²'/ H#L/ in which: L is the length of said other tube portions (12) measured from the articulation or pivot point (31), H is the vertical distance from 'said other tube portions (12) to the highest overflow point (17') in the inverted U-shaped portion (17) . F is the horizontal distance between the outer end (13') in the interior of the lying U-tube member (13) and the highest point in the inverted U-shaped tube portion (17) and D the maximum water head in the container (1) measured from said other tube portions (12).

7. Flushing arrangement according to any one of claims 1 - 6, characterized in that there is provided a resilient abutting element (15) at the bottom (2) of the container (1) .

8. Flushing arrangement acacording to any one of claims 1 - 7, characterized in that there is provided a stop (39) for limiting the maximum elevation of the tube assembly (10) .

9. Flushing arrangement according to any one of claims 2 - 8, characterized in that a downwardly directed mouth (19) of a tube portion (18) extending downwards from the inverted U-shaped tube portion (17), is adapted to be located near the bottom (2) of th container (1) when the tube assembly (10) is lowered.

10. Flushing arrangement according to any one of the preceding claims, characterized in that the mouth (19) of the tube assembl has a smaller opening than the remaining tube portions and members in the tube assembly (10).

11. Flushing arrangement according to any one of the preceding claims, characterized in that the maximum angular movement (V) between the lowered position and the maximum elevated position, is approximately equal to 30°.