GB2102543A

GB2102543A - Liquid level control

Info

Publication number: GB2102543A
Application number: GB08217759A
Authority: GB
Inventors: Hansjorg Brombach
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-06-19
Filing date: 1982-06-18
Publication date: 1983-02-02
Also published as: GB2102543B; DE3124132A1; DE3124132C2

Abstract

A process and apparatus for regulating flow into a container or regulating the liquid level in a container are described. A closure plate (21) is moved with a composite movement from a position in which the opening of the infeed pipe (13) is wholly free, to a closure position where the plate (21) is pressed against the pipe end. The closure plate (21) is mounted on one end of an arm (20) which is mounted with its other end swivellably about an axis (30) on a two-armed lever (15). This lever (15) is swivellably mounted about a main axis (14), and carries on one end a float (16) and at the other end a counter- weight (19). A liquid ballast (33) can be present in the float (16). The two axes (14, 13) and a stop (24, 25) cooperate to effect the composite movement as the liquid level rises or falls, raising or lowering the float (16). <IMAGE>

Description

SPECIFICATION Liquid level control The invention relates to liquid level control, particularly to a process for controlling the infeed into a container or for controlling the liquid level in the container in which a closure element is moved in front of an inlet orifice and pressed against the orifice by means of a float. The invention likewise relates to apparatus for controlling feed into a container or the liquid level in a container with a swivellably mounted float and a swivellably mounted closure element connected with this for closure of an infeed orifice. Devices of this nature are used in the water industry.

It is already known to mount at the end of an infeed tube a closure plate which is connected with a rod to the other end of which a flat float is iinked. On rising water level the float is lifted so that, via the rod, it closes the closure plate (see German Patent Specification 2614731). In this arrangement two relatively large floats are necessary in order to apply the force necessary for closure. The axis of the closure plate in this apparatus lies below the maximum water level so that it can easily give rise to pollution.

It is likewise known (from German Offenlegungsschrift 2 845 086) to arrange a closure plate on the end of a rod which is connected, with the assistance offourtwo-armed levers, to a large float. On lifting the float the rods, because of their parallel guidance, are pushed vertically downwards wherein however the closure plate approaches the end of the tube at an angle of about 45 . Large forces are necessary in this case.

It is likewise known (from German Offenlegungsschrift 2 927 894) to mount a closure flap in front of an opening, the free movable end of which is linked to one end of an angled lever, the other end of which is provided with a float. In this case all of the linkage points and levers lie below the water surface.

According to a first feature of the present invention there is provided a process for regulating the inflow of liquid into a container or for controlling the liquid level in a container in which a closure element is moved in front of an infeed orifice by a float, wherein the closure element is moved substantially parallel to the surface of the infeed orifice until it lies wholly in front of the orifice and thereafter moved to press substantially perpendicularly against the orifice to close this and vice versa.

The invention further provides apparatus designed to carry out this process, and specifically apparatus for controlling the inflow of liquid into a container or for controlling the liquid level in a container, wherein feed of liquid to the container is via an infeed orifice the apparatus comprising a swivellably mounted float, a swivellably mounted closure element connected to the float for closure of the infeed orifice, a lever arm to which the float is rigidly connected, the lever arm being mounted to swivel around a first fixed axis, and means mounting the closure element on the lever arm swivellably about a second auxiliary axis, whereby as the float rises, the closure element first moves across the infeed orifice and is then pressed against the orifice to restrict or prevent liquid flow therefrom.

Apparatus of this type can be constructed simply and be made almost proof against breakdown. The danger of pollution may be kept as small as possible by suitable design, and it is possible to construct the apparatus with a generally flat profile, so saving space.

In the process of the invention, the movement of the closure element, first essentially parallel to the orifice, e.g. to the surface of a pipe end, until it lies wholly in front of the orifice and then perpendicularly to press against the orifice, is accordingly composed of two movements running substantially perpendicular to one another. This makes it possible that the closure element, between the fully open position and the fully closed position, traverses a path as small as possible so that the forces available for carrying out the process, preferably generated by means of a float on the surface of the liquid in the tank, can be used as well as possible.

In apparatus according to the invention for carrying out the process the float is rigidly connected with a lever arm swivellable about a first fixed axis, on which lever arm the closure element, preferably a closure plate, is mounted swivellably about an auxiliary axis. With the aid of this solution proposed by the invention a composite movement of the closure plate may be achieved of the float lever while then a simultaneous movement of the closure plate about the auxiliary axis and of the float lever about the first fixed axis takes place.

Preferably the movement of the closure plate relative to the float and/or the movement of the float is limited at least on one side by stops. Thereby it can be achieved that during a part of the movement for example no composite movement takes place.

Advantageously a stop is provided for limiting the opened position.

Preferably the closure plate is arranged on the end of an arm, and a line normal to the centre of its surface essentially runs through the first fixed axis.

Because of the length of the arm it can be achieved that the swivelling movement carried out by the closure plate alone approaches as much as possible a straight line movement.

Preferably the float lever is two armed, wherein at the other end of the lever a counterweight is arranged. This counterweight can be used to strengthen the forces applied by the system.

In order to guarantee that the float can be particularly easily manufactured and well guided, it is preferred that the float lever be composed of two lever plates running parallel to one another.

The counterweight is arranged with advantage in such a way that in the opened condition it generates a positive opening moment. This positive opening moment makes it possible that even with a sticky bearing or with the arm fouled the closure plate is satisfactorily opened which in turn makes it possible to work with simple bearings.

For strengthening this positive opening it is preferred that the float has flat sides and is of elongate section, and that with the closure plate closed the flat sides of the float run essentially parallel to the liquid surface. In this position of the float, this has its maximum force.

Preferably in the closed condition the plane including the first fixed axis and the auxiliary axis is substantially perpendicular to the plane including the first axis and the centre point of the closure plate.

This means however that in closed condition the maximum force made available by means of the counterweight and the drive of the float acts on the closure plate, so that even with high water pressure satisfactory closure of the orifice is made possible.

Preferably the axes are arranged above the highest level to which the liquid can rise, to minimise the dangers of pollution and wear on the axes.

In order to make possible a particularly firm closure of the orifice, even with high water pressure, the invention proposes that the length of the float lever arm is large relative to the distance between the first fixed and the auxiliary axis.

Preferably the float has a longitudinally extending oval cross-section in a plane perpendicular to the first fixed axis. The longitudinally extending shape generates in closed condition a large drive force. The oval rounding off makes possible, in connection with a further feature in accordance with which namely a relatively small quantity of liquid ballast is present in the float, a type of displacement of the total centre of gravity of the float. In the open condition the oval rounding off lies at the rear side of the float so that the liquid ballast collects in this part. On closing the closure plate the float is indeed turned so that the liquid ballast moves into the rounded part i.e. lying nearer the first fixed axis. A sort of displacement of the centre of gravity relative to the first fixed axis accordingly takes place.

In a further development it is provided that in the opened condition the counterweight is arranged on the same side of a vertical plane including the first fixed axis as the float and in the closed condition lies on the other side from the float. This likewise means an increase of the closure force and simultaneously an increase of the opening force of the float.

According to a further feature it is provided that the closure plate, or at least its lower half, has a peripheral contour matched to the orifice, e.g. to the end of the pipe. If the end of the pipe is cut off obliquely and accordingly has an elliptical shape, then according to this feature the closure plate likewise, at least in its lower half, has an elliptical periphery. Accordingly it is possible in the first part of the closure movement to move the leading point of the closure plate through the surface of the pipe end. After the swinging movement is finished the closure plate is located at the smallest possible distance from the end of the pipe. For the subsequent straight line movement of the closure plate perpendicular to the surface of the pipe end then only a very small path needs to be traversed.

In the opened condition the flat underside of the float lies obliquely relative to the direction of flow from above to below in the region of the water flowing from the tube. Accordingly on the beginning of filling of the container the water stream meets the underside of the float. The dynamic pressure of the water stream ensures that the float is lifted with certainty.

Further features, details and advantages of the invention are evident from the claims and from the following description of a preferred embodiment of the invention, which is illustrated in the accompanying drawings, in which: Figure 1 shows a schematic side view of apparatus in accordance with the present invention; Figure 2 is a plan view of the arrangement shown in Figure 1; and Figures 3 to 5 are schematic illustrations of the positions adopted by the apparatus with different liquid levels.

Figure 1 shows a longitudinal section through a container 11 which is arranged below a dam 12 and in which an infeed pipe 13 debouches.

Swivellably mounted around a first fixed axis 14 are two lever plates 15 of which only one is to be seen in Figure 1. On the lower side of the lever plates 15 as seen in Figure 1 is rigidly fixed a float 16 which in cross-section has the form of a longitudinally extending oval, the flat faces of which, i.e. sides 17, 18, run essentially at an angle of 45 relative to the horizontal when the apparatus is in the position shown in Figure 1.

In each case on the other ends of the lever plates 15 there is arranged a counterweight 19 which extends between both lever arms 15. In the open position illustrated in Figure 1 the counterweight 19 lies vertically to the right of axis 14 i.e. on the same side as float 16.

Mounted swivellably on the lever plates 15 is an arm 20, to the free end of which a closure plate 21 is fixed. The centre normal to the closure plate runs essentially through the axis 14. For stiffening the plate a support sheet 22 is provided. Arm 20 is swivellably mounted on lever plates 15 on an auxiliary axis 30 which is indicated in Figure 1 as a small circle. Arm 20 has a projection 23 which, in the position illustrated in Figure 1, is supported on the float 16.

Arm 20 has a nose 24 which projects somewhat past the closure plate 21.

The front end of the infeed pipe 13 has on its upper side a closure stop 25 which cooperates with the nose 24 on arm 20.

Illustrated to the right of the float 16 with the aid of line 26 the water level line is indicated which ought to be regulated with the aid of the closure device.

In Figure 2 the shape of the container 11 is evident which at its outlet side has a constriction with an inserted shutter 27.

In Figures 3 to 5 the mode of operation of the apparatus according to the invention is to be seen.

Figure 3 shows the apparatus in wholly opened condition. Here arm 20 lies against a stop 28 which is only shown schematically. The counterweight 19 is in the same fashion as the float 16, arranged on the right hand side of axis 14 so that both give rise to a positive opening moment.

It is likewise to be seen that in the lower rounded part 29 of the float 16 a liquid ballast 33 is arranged.

Further turning of the lever plates 15 together with the counterweight 19 and the float 16 is prevented by float 16 lying against the projection 23 of the flap arm 20.

If the water now rises relative to the water level in Figure 3 the lifting of float 16 effects a turning of the lever plates 15 about the main axis 14, while arm 20, because of its weight, continues to lie with its projection 23 on the float 16, until its nose 24 abuts on the closure stop 25 of the infeed pipe 13. The movement which is carried out between the position shown in Figure 3 and that in Figure 4 is a swinging movement about the axis 14, wherein because of the relatively large length of arm 20 this swinging movement causes the plate 21 approximately to execute a straight line movement. The distance illustrated in Figure 4 between the closure plate 21, which is lined with a rubber seal 31, and the surface 32 of the opening of the infeed pipe 13 is accordingly determined, in that the closure plate 21 must be able to get past the infeed pipe 13 without touching.

On further rising of the water level the float 16 is raised further wherein now the liquid ballast 33 slowly moves away to the left hand side of the float 16. The flap arm 20 sits with its nose 24 on the closure stop 25 so that on further turning of the lever plate 16 now relative swivelling of arm 20 takes place about the auxiliary axis 30, and at the same time the auxiliary axis 30 turns about the main axis 14 and moves in the direction towards the end of pipe 13.

This composite movement is an essentially straight line movement normal to surface 32. At this stage the counterweight 19 moves to the other side of axis 14 so that the closure force is further strengthened.

In the device proposed by the invention the closure plate 21 is accordingly first moved essentially in the direction of the surface of the end of the infeed pipe 13 in the shortest way possible in front of this opening, whereon it comes to be at a short distance in front of this opening. Then because of a toggle lever type conversion into a composite movement the closure plate 21 moves perpendicular to the surface 32 of the opening of the infeed pipe 13 until the infeed pipe 13 is closed. The force for closing the tube is further strengthened in that the counterweight 19 comes to be on the other side of axis 14 while simultaneously the liquid ballast 33 in the float 16 likewise moves itself in the direction towards axis 14, both being to the left as seen in the drawings.

The stop 23 is so arranged that when it lies against float 16 arm 20 runs essentially perpendicular to the plane of axes 14 and 30.

The connection line between the centre point of the float and the main axis 14 forms, with the connection line between the counterweight 19 and the main axis 14 an angle of 90 to 180 preferably of 120 to 150 . In this connection the auxiliary axis 30 preferably lies on the projection of the float lever arm. The longitudinal direction of the cross-section of the float runs at an angle of 30 to 60 preferably of 45 relative to the float lever arm.

The length ratio of the distance between axis 14 and axis 30 relative to the length of the float lever arm preferably amounts to 1 : 5 to 1: 20, most preferably 1:10. The length ratio arm 20 to the distance between axis 14 and axis 30 preferably lies in the region of 5:1 to 50:1, most preferably in the regionof10:1to20:1.

The volume of liquid ballast 33 is preferably smaller than a third of the inner volume of the float, preferably smaller than a fifth, most preferably about 10% of the float inner volume.

As infeed there can be not only a pipe but for example an opening in a plate. In place of a closure plate, a closure element can also be used, for example a ball or an ellipsoid.

Claims

1. A process for regulating the inflow of liquid into a container or for controlling the liquid level in a container in which a closure element is moved in front of an infeed orifice by a float, wherein the closure element is moved substantially parallel to the surface of the infeed orifice until it lies wholly in front of the orifice and thereafter moved to press substantially perpendicularly against the orifice to close this and vice versa.

2. A process according to claim 1 wherein the closure element is moved by means of a float on the surface of the liquid in the tank.

3. Apparatus for controlling the inflow of liquid into a container or for controlling the liquid level in a container, wherein feed of liquid to the container is via an infeed orifice the apparatus comprising a swivellably mounted float, a swivellably mounted closure element connected to the float this closure of the infeed orifice, a lever arm to which the float is rigidly connected, the lever arm being mounted to swivel around a first fixed axis, and means mounting the closure element on the lever arm swivellably about a second auxiliary axis, whereby as the float rises, the closure element first moves across the infeed orifice and is then pressed against the orifice to restrict or prevent liquid flow therefrom.

4. Apparatus according to claim 3 and including stop means limiting the movement of the closure element relative to the float and/or movement of the float.

5. Apparatus according to claim 3 or 4 wherein the closure element is a closure plate mounted on the end of an arm, and wherein a line perpendicular to the centre of the surface of the closure plate intersects or nearly intersects the first fixed axis.

6. Apparatus according to any one of claims 3 to 5 wherein the lever arm to which the float is attached is one arm of a two-armed lever and wherein a counter-weight is arranged on the other arm.

7. Apparatus according to any one of claims 3 to 6 wherein the lever arm carrying the float is constituted by two lever plates running parallel to one another.

8. Apparatus according to claim 6 or claim 3 is dependent on claim 6 wherein with the closure element away from the pipe end the counterweight generates a positive opening moment.

9. Apparatus according to any one of claims 3 to 8 wherein the float is of elongate section in a plane perpendicular to the first fixed axis, and wherein its length runs substantially parallel to the water surface when the closure element is pressed against the orifice.

10. Apparatus according to any one of claims 3 to 9 wherein when the closure element is pressed against the orifice the plane including the first fixed axis and the auxiliary axis runs essentially perpendicular to the plane including the first fixed axis and the centre of the closure element.

11. Apparatus according to any one of claims 3 to 10 wherein both the axes are arranged to lie above the level of the liquid sufficient to cause the apparatus to stop further liquid flow through the infeed orifice.

12. Apparatus according to any one of claims 3 to 11 wherein the distance from the point of application of force by the liquid on the float to the first fixed axis is large relative to the distance between the first fixed axis and the auxiliary axis.

13. Apparatus according to any one of claims 3 to 12 wherein the cross-section of the float in a plane perpendicular to the first fixed axis is a longitudinally extending oval.

14. Apparatus according to any one of claims 3 to 13 wherein the float contains a small quantity of liquid.

15. Apparatus according to claim 6 or to any one of claims 7 to 14 when dependent thereon wherein when the closure element is away from the orifice the counterweight lies on one side of a vertical plane including the first fixed axis, and wherein when the closure element is pressed against the orifice, the counterweight lies on the other side of this vertical plane.

16. Apparatus according to any one of claims 3 to 15 wherein the closure element is a closure plate and at least the lower half of the closure plate has a peripheral contour matched to the contour of the orifice.

17. Apparatus according to any one of claims 3 to 16 wherein the float has an elongate section in a plane perpendicular to the first fixed axis, and wherein, when the closure element is away from the pipe end, the length of the float runs obliquely relative to the direction of liquid flowing from the orifice.

18. Apparatus for controlling liquid flow substantially as hereinbefore described with reference to the accompanying drawings.

19. A process of controlling the liquid level in a tank substantially as hereinbefore described with reference to the accompanying drawings.