WO1999020100A1

WO1999020100A1 - A liquid level control device

Info

Publication number: WO1999020100A1
Application number: PCT/AU1998/000869
Authority: WO
Inventors: Ah N. Fah
Original assignee: Fah Ah N
Priority date: 1997-10-20
Filing date: 1998-10-20
Publication date: 1999-04-29
Also published as: ZA200002030B; AUPO989997A0; MY130127A

Abstract

The liquid level control device includes casing (1) nested between two floats (2, 10). Float (10) fits inside casing (1) and controls water flow through inlet (3) via closure (12). The base of casing (1) has ports (17) to allow water to flow into a container. Float (2) is affected by the level of water in the container and opens/shuts vent (8) via closure (9). When the water level is low, float (10) causes closure (12) to operate and feed water into casing (1) and out ports (17) into the container. As the water level rises, float (10) is held down by air trapped inside casing (1) by vent (8) being closed. As float (2) becomes buoyant, it rises to open vent (8). Float (10) then rises and shuts off the water flow. When the water level falls, float (2) lowers and seals vent (8). If the water level continues to drop a partial vacuum is created inside casing (1) and maintains the water level therein. When the water level falls below entry (16), air enters into casing (1) through breather tube (6) and hole (15) to relieve the partial vacuum. Float (10) drops and opens inlet (3) to restart the water filling cycle.

Description

TITLE: A LIQUID LEVEL CONTROL DEVICE

FIELD OF THE INVENTION

This invention relates to a liquid level control device.

BACKGROUND TO THE INVENTION

Reference is made to my Patent No. 636542 and to my Patent No. 630877 and the whole of the subject matter of the specifications thereof is to be considered to be imported hereinto.

In the specification of my Patent No. 636542, there is claimed as follows in Claim 1:- A liquid level control device adapted to be located in a vessel,

the device comprising

a first flow controller comprising

a first float located in a first chamber,

the first chamber being open at or adjacent its bottom to allow water ingress and egress and having a first vent to allow egress of air, and

a first valve associated with the first float such that, in use, when the float is at a down position when the level of water in the chamber is at or below a first predeteimined level, the first valve will open to allow water into the vessel and into the first chamber, to tend to raise the first float and to displace air in the first chamber via the first vent,

and such that, in use, when the first float is at an up position when the level of water in the first chamber is at or above a second predetermined level, the first valve will close to inhibit further water flow into the vessel via the first valve;

a second flow controller comprising

a second float, and

a second valve associated with the second float and connected to the first vent such that, in use, when the second float rises, in consequence of the first valve allowing water into the vessel, the second valve will open to allow air to flow from the first chamber via the first vent and the second valve to escape to atmosphere external of the controller,

and constructed and arranged such that when the water level in the vessel drops to a third predetermined level in consequence of water in the vessel being used or being removed, the second float will fall to a level to close the second valve before the first float has fallen to a level to open the first valve, to thereby inhibit air flow via the first vent into the first chamber to establish, as the water level in the vessel falls still further, a partial vacuum in the first chamber which will maintain the water level therein at a level such that the first float will not fall to a level to open the first valve; and

a breather for the first chamber located such as, in use, when the water level in the vessel falls to below a fourth predetermined level in consequence of water in the vessel being used or being removed, to allow air to enter into the first chamber to overcome the partial vacuum to allow water to flow out of the first chamber to allow the first float to fall to a level to open the first valve to commence again, in use, allowing water into the vessel.

A liquid level control device in accordance with the above will be called "a liquid level control device of the kind described" or "a device of the kind described".

I will also make reference to "my old device" which is a device as described in Patent No. 636542 with reference to the passages therein headed "Brief Description of the Views of the Drawings:", "Component list:" and "Detailed Description with Respect to the Drawings:".

SUMMARY OF THE INVENTION

The present invention provides :-

a liquid level control device of said kind described and having one or more of the following features:-

a. the first vent, when not in closed condition, is open directly to the ambient conditions outside the first chamber;

b. the first vent comprises a spigot end or a socket end outside of the first chamber;

c. the second valve comprises the first vent and a second valve closure adapted to engage on the spigot end or to be received in the socket end of the first vent when the second float is in a lower position to close the first vent and when not so engaged the first vent is open when the second float is in an upper position;

d. the first valve comprises a tube which is substantially straight and which tube extends from outside the first chamber to inside the first chamber;

e. the end of said tube in the firsts chamber has a spigot end or a socket end;

f. the first valve comprises a first valve closure adapted to engage on the spigot end or to be received in the socket end of said tube when the first float is in an upper position to close the spigot end or socket end of said tube and when not so engaged said tube is open when the first float is in a lower position;

g. the first chamber is substantially or at least entirely open at its bottom;

h. the first float is mounted to the first chamber so as to be removable without any other disassembly of the device;

i. the first valve closure comprises a generally cylindrical member mounted in a boss or aperture associated with the first float;

j. the first float is mounted to the first chamber by lugs extending laterally and which are received in slots in the first chamber which normally extend downwardly;

k. the first float comprises a body which is substantially entirely open at its bottom;

1. the second float comprises a hollow body which is entirely sealed at its lower end against ingress of water;

m. the second float overlies at least part of the first chamber;

n. the second float is mounted to an arm which at least in part overlies the first chamber; o. the arm is pivotally mounted to the first chamber;

p. the arm carries the second valve closure on its underside;

q. the second float is formed of a substantially rigid plastic;

r. the second float is of weight such as not to substantially need additional weighting; and

s. the second float has means for mounting a weight if that be desired.

PREFERRED ASPECTS OF THE INVENTION

In a preferred aspect, the present invention provides:-

a liquid level controller of said kind described and wherein

said vent is located in the top of the first chamber,

the second float is pivotally attached to the first chamber,

the second valve comprises said first vent and a closure mounted to the second float such that when the second float is in a down position said first vent will be closed by the closure and such that when the second float is in an up position the closure will be located in relation to said first vent such that said first vent is open.

There are many others of these which may be taken individually or in combination as will be seen hereinafter.

Reference is made to a provisional specification soon to be lodged which describes a pump useful with the controller.

A specific embodiment of a controller device in accordance with this invention will now be described with the aid of the accompanying drawings which are given by way of example only and should not be considered to be limiting.

BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWINGS

Diagram 1 is a top plan view of the device,

Diagram 2 is a view from one end of the device,

Diagram 3 is a side elevational view of the device,

Diagram 4 is a cross-sectional view on line A- A in Figure 1,

Diagram 5 shows a component part partly in cross-section,

Diagram 6 shows a component part partly in cross-section,

Diagram 7 shows a component part partly in cross-section,

Diagrams 8, 9, 10 and 11 show the controller device in various conditions in operation.

INTEGER LIST

31. First controller 1. Casing

3. Water inlet

13. Spigot 10. First float

32. Float body 33. Open lower end

34. Arm

14. Pivot lugs

35. Slots for pivot lugs 11. Adjustable knob

12. Resilient first valve closure

8. First vent

36. Spigot end

6. Breather tube

16. Entry to breather tube

15. Breather hole

21. Bottom level of breather tube

17. Side entry to first casing

2. Second float

37. Top cover of second float

4. Slots or apertures for weights

38. Weights

39. Arm for top float

41. Pivot lugs

5. Slots for pivot lugs

7. Adjustable knob

9. Resilient second valve closure

18 A, B, C & D Varying water levels outside first casing

19. Air trapped in first casing

20A, B & C Varying water levels within first casing.

DETAILED DESCRIPTION WITH RESPECT TO THE DRAWINGS

The liquid level controller device shown in the accompanying drawings comprises a first controller 31 which is itself comprised of a casing 1.

A water inlet 3 is provided to the casing 1 and on the inside of the casing 1 the water inlet 3 terminates in the spigot 13.

Within the casing 1 is a first float 10.

The first float 10 comprises a float body 32 which has an open lower end at 33. The first float 10 further comprises an arm 34 which is provided with pivot lugs 14 which locate in slots 35 in the casing 1.

The slots 35 are so shaped as to capture the pivot lugs 14 in a way that will hold the float 10 in position but which will enable ready assembly or disassembly.

The first float 10 carries an adjustable knob 11 on which is mounted a resilient first valve closure 12.

The adjustable knob is not an essential feature by any means and in modifications the applicant has omitted it and instead has mounted the resilient first valve closure 12 in a blind hole in the arm 34.

It is to be noted that the water inlet 3 and the spigot 13 are directly in line and involve no bends at all. This will be useful if there is a need for cleaning.

The casing 1 has a first vent 8 which, on the outside of the casing 1, is provided with a spigot end 36.

A breather tube 6 is also formed with the casing 1.

An entry 16 to the breather tube 6 is provided and a breather hole 15 extends from the breather tube 6 into the first casing 1 at 15.

The breather tube 6 has a bottom level at 21 and it is to be noted that that bottom level is somewhat higher than the bottom of the casing 1.

Side entry ports 17 to the first casing 1 are provided. Those ports may be in addition to or alternative to the breather tube.

Mounted above the casing 1 is a second float 2.

The second float 2 comprises a hollow body which is maintained closed by a top cover 37.

That top cover 37 may be secured in position by an appropriate adhesive or may be welded as to be part of the second float 2. What is important here is that the second float 2 should be made impervious to water penetration. However, there are other means of achieving this including filling the second float 2 with a foam material or blow moulding it as a closed body.

Second float 2 may have slots or apertures 4 for receiving weights 38.

Those slots or apertures 4 preferably should not extend into the interior of the second float as in so doing they might compromise the water tightness of the second float.

The second float 2 is mounted to an arm 39 which is integrally formed with the second float 2.

The arm 39 carries pivot lugs 41 which are received into slots 5 for the pivot lugs 41 which are mounted on the top of the casing 1.

The slots 5 are so shaped as to capture the lugs 41 in a manner such as to retain the arm 39 in position but also to readily permit, by manipulation, assembly and disassembly.

The arm 39 carries an adjustable knob 7 which itself supports a resilient second valve closure 9.

As previously, the adjustable knob 7 may be omitted and applicant has found substantial success in mounting the resilient second valve closure 9 in an appropriate aperture or recess in the arm 39.

The weight, volume and consequently the buoyancy of the first float 10 and the second float 2 are important considerations. However, precise and exact values are not of themselves critical and instead will be determined by initial trial and error to obtain a construction which effectively works. In general, the applicant prefers that the liquid level controller device as shown in the drawings should have a size of approximately 120mm long, 60mm wide and 55mm high but applicant does not wish to be limited to those dimensions.

For the purposes of adjusting the buoyancy of the floats 10 and the float 2, applicant presently prefers to use thicker walls in respect of the float 2 than the float 10 (2mm as compared to 1mm) so that the second float 2 has greater weight than the float 10. Having regard to the dimensions given, this should result in the second float 2 having a weight of about 25g.

The careful selection of weights is desirable to have sufficient premise to make a tight seal on the spigot 36 by the closure 9. Closure of the spigot 36 may also be aided by the position of the closure 9 and presently the applicant prefers to locate the closure 9 about 15mm from the pivot lugs 41.

The float 2 straddles part of the casing 1.

The position of closure 12 is preferably such as to exert in use, sufficient pressure at the spigot 13 to be able to withstand a pressure of 20psig. Some trial and experiment may be needed so that the mechanical advantage exerted is sufficient to hold the pressure desired.

As previously stated, the side entry 17 and the breather tube 6 may be alternative or additional to one another but in fact both may be omitted provided that the casing 1 is shaped or is received into a vessel shaped so that a small gap is provided between the bottom of the casing 1 and the vessel within which it is received.

The manner of operation of the liquid level controller shown in the accompanying drawings will now be described.

The controller will be placed in a vessel able to contain water and will, in practical terms, be associated with a number of plants which are to be watered in that container or from that container. One method of watering that is highly praised by the applicant is to locate - l i the container above the highest water level which is expected to be within the container and deliver water to the plant by a wick as this usually provides a fairly well controlled rate of watering. It is true that rain water may cause the container to fill above a desired level with water but this can be dealt with to some degree by provision of overflow or simply by natural evaporation.

Some of the methods of watering are described in more detail in my Patent No. 630877.

Commencing from the state in which the container contains no water, such as Diagram 4, the float 10 will be in a down position as there is no water to buoy it up and the closure 12 will be spaced away from the spigot 13.

Thus, if water is supplied via a tube to the inlet 3 the water will flow into the container to commence filling from below a first predetermined level indicated by line 18 A.

The water that is supplied may flow out of the slot 17 or, dependent on the position of the bottom of the casing 1, directly out of the bottom of the casing 1 into the container. Water will continue to flow but little or no water will build up inside the casing 1 excepting for the limited amount which can occur due to the compression of air within the casing 1. Such compression of air within the casing 1 will occur because, as is shown in Diagram 4, the float 2 will be in a down position and the closure 9 will be closing the spigot 36. Thus, there will be likely to be some compression. That compression can escape via the breather hole 15 but once the water level exceeds the bottom of the breather tube 6 at 21 then there is no longer an escape for air.

The float 2 will remain in a down position until the water level in the container has risen to a substantial level as indicated by line 18B in diagram 9 but at the stage of level 18B the float 2 will become buoyant and rise to open the vent 8 by removal of the closure 9 from the spigot 36 and this will allow air entrapped within the casing 1 to escape via that vent 8.

As air escapes from within the casing 1 via the vent 8, water from outside the casing 1 will flow into the casing 1 through slot 7 or through the lower end of the casing 1 and this will cause the float 10 to rise to bring the closure 12 into engagement with the spigot 13 to stop the flow of water through the inlet 3.

In use, the water level inside the casing 1 will eventually settle to the same level, 20B, as outside the casing 1 in lieu of the level 18B.

At that stage, a static condition will exist for a period of time and during that period of time a plant in the container will consume water and the water level 18C outside the casing 1 will slowly drop as is shown in Diagram 10.

At about the water level 18C, the float 10 would have lowered sufficiently whereby the closure 9 will again make a seal on the spigot 36. This will mean that air and water within the casing 1 are trapped as air is prevented from entering via the breather hole 16, the lower end 21 still being underwater, and a partial vacuum will be created within the casing 1.

This last results in the float 10 being maintained substantially in its upper position by the higher water level 20B within the casing 1 and as such the closure 12 remains in contact with the spigot 13 and no water enters.

As more water outside the casing in the container is taken up by the plant or by natural evaporation, the water level 18C will continue to drop slowly until it is below the bottom of the breather hole 21 whereby it is lower from the bottom 21 by a few millimetres. When this happens, air will naturally flow into the breather tube 6 and then into the casing 1 via the hole 15.

This last will cause a partial vacuum inside the casing 1 to now be broken and as a consequence that water that was trapped inside the casing 1 will be released to the outside via the slots 17 at the bottom of the casing.

When the water level within the casing 1 has lowered to the level 20C, the bottom float will have moved to a down position whereupon closure 12 will move away from spigot 13 and allow the above described cycle to repeat. Various times are now given which refer not to every incident but in general to rates of filling and emptying in a temperate climatic zone.

Depending on water pressure and the volume of the container, the time for filling the container between lines 18A and 18B is not likely to be more than 3 - 4 minutes.

For the water level to change from 18B to 18C and then to 18D can vary from a few hours to several days and this very much depends on the rate of water consumption by the plants which is affected by size and weather conditions and the rate of evaporation in the place where the container is located.

The water level 20A in casing 1 will only rise after the water level in the container approaches 18B. From 20A to 20B, is likely only to take a few seconds as the volume inside the casing 1 is relatively small particularly in regard to the volume of the container for plants.

The water level 20B will commence falling only after water level in the container approaches 18D.

The time for the water level to move from 20B to 20C will only take a few seconds.

Obviously, the liquid level controller device can be made of a size and be positioned and operated to obtain a very wide range in variations in water levels but applicant presently prefers that the difference in height between levels 18D and 18B should be about 0 - 30mm.

To change that range, the height of the casing 1 can be substantially increased.

The level at which the float 2 will move the closure 9 away from the spigot 36 can be varied by the use of weights 4 or by the weight of the float 2 itself.

The above described valve can be used in many different ways in that a number of plants can be watered at once and the plants of different variety which will tend to ensure that they water on demand which is considerably better than merely maintaining a particular level of water.

A number of containers may be connected by overflow means from one container to the other or may be a connection which maintains the water levels equally in several containers.

A modification of the water inlet 3 can be made so that water may be directed upwardly initially so as to feed one or more drips or sprinklers.

The dispensing of fertiliser may be done in a number of ways as has been discussed in my Patent No. 630877.

Making a comparison between the valve as described above with respect to Diagrams 1 - 11 and the old device previously referred to, the following points of comparison may be made.

1. The old device used an inlet which had a right angle bend. This made it easy for dirt to accumulate and hence blockages were a major concern. Clearing those blockages was difficult. By comparison with the new valve, water entry is in a direct straight line which reduces the problem of blockages and, if blockages do occur, they may be easily cleared by a straight pin or straight piece of wire.

The old valve used a total of 16 parts with a consequent high assembly cost.

The new valve as described with respect to the diagrams, comprises 8 parts but this can be reduced by omitting the adjustable knobs 11 and 7 which will give a component count of 6 components and can be further reduced by closing the upper end of the float 2 by omitting the cover 37 and using an alternative closure method or forming in such a way that an effective seal is obtained. Still further, the component count could be reduced by replacing the closures 12 and 9 by conical members which would seat appropriately. This last, while reducing the component count, may not be favourable as better quality machine would be necessary and. there would be risk of physical damage by a clumsy user. The use of lesser number of parts reduces assembly cost and makes the valve more reliable.

3. The old valve had a venturi tube which kept water trapped in it or when the valve was turned upside down which prevented air movement.

In the new valve there is no venturi tube and air in the casing 1 is released directly to atmosphere through the vent 8.

4. In the old valve the floats were blow moulded and were subject to fluctuations in volume as a result of changes in air temperature with consequences of floats jamming. A reduction of temperature would make the floats contract and have less flotation.

The new valve has floats which are more solid and are preferably injection moulded and thus they are relatively rigid and not as subject greatly to changes in shape due to temperature changes.

5. In the old valve, the float 2 needed to be weighted with a bolt that was screwed into its wall. This provided a weakness which would enable water to get into the equivalent of float 2.

In the new valve, applicant has made the float 2 completely air tight and has attained the necessary weight by use of appropriate wall thickness without the need of weights themselves but, if required, to be totally external of the interior ofthe float 2.

6. In the old valve, the equivalent of the valve closures were often difficult to effect proper and decent closure. In the new valve, the use of the adjustable knobs reduces this but such adjustable knobs are not truly essential.

7. The old valve had a height of 75mm which made it difficult to locate it in small containers. The new valve has a lower profile which is presently at 45mm which means that it can be easily fitted into pots such as those disclosed in my earlier patents.

The old valve had two casings. The new valve has only one casing.

8. When the old valve was fully immersed in water which sometimes happened due to overflowing or rain or other excess water causes, the valve would often get so full of water as to no longer operate properly. The new valve can be completely immersed in water and this seems largely to be due to the vent 8.

9. The old valve could not be turned upside down as the venturi tube was inclined to get choked with water. In particular, customers had a tendency to turn valves upside down during cleaning or inspection and so increasing this problem. The new valve, contrariwise, can be turned upside down without serious effect.

10. The old valve was only good in practical terms to about 2psig. The new valve can cope with higher pressures and applicant has had some considerable success at up to 30psig. At such higher pressure, the refilling of containers will occur faster and hence smaller and less expensive tubing may be used or same size tubing may be utilised for large scale operation.

The new valve can be readily screwed to the bottom of a vessel.

The float 2 of the new valve can be pivoted about 180° whereupon the new valve will become a constant level device. This is useful to maintain a supply to a newly potted plant in its first week or so.

The float 2 may be open at its bottom if desired and need not be hollow as presently shown. It was formed as presently shown for cheaper moulding reasons only.

The claims, illustrations, photographs and drawings, if any, form part of the disclosure of this specification as does the description, claims, illustrations, photographs and 20100

- 17 - drawings of any associated provisional or parent specification or of any priority document, if any, all of which are imported hereinto as part of the record hereof.

Finally it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements or parts without departing from the spirit and ambit of the invention.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS :-

1. A liquid level control device of said kind described and having one or more of the following features:-

the end of said tube in the firsts chamber has a spigot end or a socket end;

g. the first chamber is substantially or at least entirely open at its bottom;

h. the first float is mounted to the first chamber so as to be removable without any other disassembly of the device; i. the first valve closure comprises a generally cylindrical member mounted in a boss or aperture associated with the first float;

m. the second float overlies at least part of the first chamber;

n. the second float is mounted to an arm which at least in part overlies the first chamber;

o. the arm is pivotally mounted to the first chamber;

p. the arm carries the second valve closure on its underside;

q. the second float is formed of a substantially rigid plastic;

s. the second float has means for mounting a weight if that be desired.

2. A liquid level controller of said kind described and wherein

said vent is located in the top of the first chamber, 0100

- 20 - the second float is pivotally attached to the first chamber,

3. A liquid level controller as claimed in Claim 1 wherein

the first valve comprises

a passage extending from the interior of the casing to the exterior thereof

and wherein the first valve and the passage lie in substantially or straight line.

4. A liquid level controller as claimed in Claim 1 wherein the first valve opens directly to the atmosphere external of the controller.

5. A liquid level controller substantially as hereinbefore described with reference to any one of the accompanying drawings.

6. The steps, features, compositions and compounds referred to or indicated in the specification and/or claims of this application, individually or collectively, and any and all combinations or any two or more of said steps or features.