A volumetric control device for a fluid volume

Abstract

A volumetric control device for controlling a fluid volume comprises a fluid inlet to the fluid volume; a body for arrangement in the fluid volume, the body defining a chamber having a float provided therein; a first control valve; and a second control valve. The first control valve is operable between an open configuration and a closed configuration, the open configuration arranged to open the fluid inlet in response to the float sinking to a first position in the chamber and the closed configuration arranged to close the fluid inlet in response to the float floating to a second position in the chamber. The second control valve is operable between an open configuration and a closed configuration, the open configuration arranged to allow fluid to drain through an outlet from the chamber thereby emptying fluid from the chamber and sinking the float to the first position and the closed configuration arranged to close the outlet thereby holding a column of fluid in the chamber and floating the float in the second position. In contrast to traditional float valves operating in large fluid tanks which commonly cause rapid wear to pump parts and valve seals due to slow valve closure, the control device provides the advantage that upper and lower levels of the fluid can be set, and 'quick stop / start' achieved by suspending a float chamber within the fluid of the tank. The float chamber is filled from the tank fluid and the movement of the float within the chamber controls the flow of fluid into the tank via an actuating arm operating either one or more pump switches or stop valves. The level of fluid within the float chamber, and thus the movement of the float, can be controlled by a ball valve at its base. This alternately holds the chamber full or empty, achieving quick stop and start at upper and lower set levels.

Description

[0001]A VOLUMETRIC CONTROL DEVICE FOR A FLUID VOLUME Field of the Invention The present invention relates to a volumetric control device for a fluid volume, in particular a means of maintaining a desired level in a volume of fluid; more particularly but not exclusively a means of maintaining a desired level of liquid in a water tank for example. Background In many societies across the world there is an increasing awareness of the need to save energy, limit wear, replacement and maintenance needs in all fields. In the field of water tanks, it is common that in order to maintain a desired level within the tank there will be a valve. This valve will often be a ballcock or similar type, such that the ball drops as the water level falls, the valve will subsequently be opened, to allow more water into the tank. As the level within the volume is maintained within the small range of the ballcock's switching movement on / off cycles are numerous. This causes wear to components especially in large tanks with slow level changes where the valve rarely fully opens or closes but also in small tanks where level changes are rapid and frequent. Prior Art EP 3101322 (FOMINAYA) discloses a cock for filling tanks, comprising a hollow head that supports a valve device associated with a float by means of an intermediate device, also comprising a vertical tube connected to the hollow head, in which the vertical tube is housed inside a central passage in the float which moves as the level of water in the tank rises and falls. The float is connected to a bush that is coupled around the vertical tube along which the bush moves, and the upward and downward movement of the float drags the bush when the float is anchored thereto. CN 102 080 738 (CHEN) discloses a float ball valve which comprises a valve body connected with a water supplying pipeline, a float ball, a valve core, and a water storing box, wherein the valve body is provided with a switch on-off mechanism which is connected with the valve core; the valve core is matched with the inner wall of a cavity of the valve body; the switch on-off mechanism comprises an upper fixed holder, an lower fixed holder, a positioning rod and a fever, wherein the upper fixed holder and the lower fixed holder keep the valve core in the inner part of the water exhaust side and water intake side of the valve body; the positioning rod and the lever are connected with the valve core; the upper end and the lower end of the valve core are respectively connected with an upper positioning rod and a lower positioning rod. TW 200925360 (HUANG) discloses a multi-float water inlet control valve comprising: a valve body, a valve stem movably disposed within the valve body, the valve stem being fixed with a valve plug for blocking the valve body, a linkage stem pivotally connected to the valve body for carrying the valve stem, the linkage stem extending with a stem having an end face formed as a fully-closed contact slide point, and a valve stem extending from the stem to the stem. In light of problems with the known devices, various proposals have been made, but there remains a need for an improved device for volumetric control device of a fluid volume which addresses one or more of the problems presented by prior art arrangements. In this regard, the present invention seeks to provide an alternative which preferably addresses one or more of the problems presented by prior art arrangements. Summary of the Invention In a first aspect, the invention provides a volumetric control device for a fluid volume, comprising: a fluid inlet to the fluid volume; a body for arrangement in the fluid volume, the body defining a chamber having a float provided therein; a first control valve operable between an open configuration and a closed configuration, the open configuration arranged to open the fluid inlet in response to the float sinking to a first position in the chamber and the closed configuration arranged to close the fluid inlet in response to the float floating to a second position in the chamber; and a second control valve operable between an open configuration and a closed configuration, the open configuration arranged to allow fluid to drain through an outlet from the chamber thereby emptying fluid from the chamber and sinking the float to the first position and the closed configuration arranged to close the outlet thereby holding a column of fluid in the chamber and floating the float in the second position. Preferably, the first control valve is associated with the fluid inlet and the second control valve is associated with the outlet from the chamber. Preferably, the outlet from the chamber is located in a lower portion of the chamber in use. Preferably, the first control valve comprises a pivoting float valve. Preferably, the first control valve comprises an arm and the float abuts the arm and exerts a force on it when the float is in the second position, thereby closing the fluid inlet. Preferably, the first control valve comprises an electrical switch. Preferably, the device comprises a pump for pumping fluid into the fluid volume when the first control valve is in the open configuration. Preferably, the body is cylindrical or is defined by a prism. Preferably, the chamber is cylindrical or is defined by a prism. Preferably, the float is cylindrical or is defined by a prism. Preferably, the body, chamber and float are cylindrical. Preferably, the float has a longitudinal axis which is coaxial with a longitudinal axis of the chamber. Preferably, the float comprises a hollow cylinder. In one embodiment, it comprises a tube having first and second ends and a cap is provided at each end. Alternatively, preferably the float comprises a solid cylinder and it is manufactured of a material less dense than the fluid. Preferably, the body, chamber and float each have a longitudinal axis arranged vertically in use. Preferably, an opening for fluid ingress into the chamber is defined in an upper portion of the chamber in use. Preferably, the first control valve comprises an arm and a longitudinal slot is defined in a wall of the body for passage of the arm. In one embodiment, the slot provides the opening for fluid ingress into the chamber. Preferably, the volumetric control device includes a splash guard which comprises a generally planar body which defines an opening, through which the arm projects. The splash guard provides the advantage that splashes or drops of fluid entering the fluid volume through the inlet are deflected from entering the opening, for example by running down the arm. Preferably, the second control valve comprises a float valve or ball valve. In a second aspect, the invention provides apparatus comprising a device according to the invention and a tank providing the fluid volume. The invention provides the advantage that it can be used to control the fluid volume from various sources. For example, the fluid could be water from a borehole filtered to supply cattle drinking troughs. Alternatively, or in addition, the fluid could be water from a mains water supply, water from rainwater harvesting source or grey water (e.g. wastewater from showers & sinks). In one embodiment, a plurality of volumetric control devices of the invention can be used to control a fluid volume. Preferably, each device controls a separate fluid inlet to the fluid volume wherein each fluid inlet is from a different source, for example one of the sources mentioned above. Preferably, in an embodiment wherein a plurality of volumetric control devices of the invention are provided, each device is set at a separate level so that one or more fluid inlets are used in preference to one or more other fluid inlets. For example, water from a borehole and / or rainwater harvesting source could be used in preference to a mains water supply or grey water supply. Advantageously, parts of the device of the invention can be manufactured by injection moulding, thereby minimising the costs of production. In one embodiment, there is provided a volumetric control device for a fluid volume, comprising: a fluid inlet to the fluid volume; a first (upper) control valve; a second (lower) control valve; and a mechanical switch. The mechanical switch controls when the upper valve opens and closes, dependent on whether the lower valve holds the chamber empty or full. In this way the device may advantageously ensure that the volume of water in a fluid volume may be controlled. It ensures that the level will be required to fall to the lower control valve before the inlet is opened, but rise to the upper control valve before the inlet is closed, meaning that variations in the level are not liable to cause frequent and repetitive filling prompts, and associated problems with equipment and cycling. Additionally, the mechanical switch ensures quick stop and start, preventing oscillation in the system. It may be envisaged that the mechanical switch is arranged to move quickly in relation to the filling or emptying of the volume, for example being comprised by a substantially smaller volume, to provide a quick stop activation means when an upper level is reached for the volume, and a quick start activation means when a lower level is reached for the volume. The device is therefore also claimed within a tank providing said fluid volume. In some embodiments of the device the device comprises an upper control valve that comprises a pivoting float valve. In some embodiments of the device the mechanical switch comprises a float, which float travels between the control valves, to control open and closing of the upper control valve. In some embodiments of the device the device comprises a body, also referred to as a connecting member, between the upper control valve and lower control valve, so as to allow the device to be formed, transported or installed as a whole unit, for ease and cost concerns. In some such embodiments of the device the connecting member comprises a float chamber for a float travelling within the connecting member, for example under fluid pressure related to or associated with the volume of fluid in the chamber. In some such embodiments of the device the connecting member comprises a cylindrical member with an internal bore, for example wherein a close-fitting cylindrical float is movable. The cylindrical member may be vertically arranged in use. In some embodiments of the device the device comprises a fluid ingress in an upper region of the connecting member, which may dispense into the member from the volume for example. Such fluid ingress may for example be in the form of a slot in the member. In some embodiments of the device the connecting member thereby includes a slot for passage of fluid and the upper control valve, which slot may allow water into the member from the volume. The upper control valve rod may travel in the slot under the urging of the float in the chamber. The mechanical switch may comprise a float travelling within the internal bore between the upper control valve at a first end of the internal bore and the lower control valve at a second end of the internal bore. In some embodiments of the device, the lower control valve comprises a float valve, for example including an arm having a floatation ball at a distant end. In further embodiments of the device an electrical on / off switch may replace the upper control valve so as to operate pump(s) without pressure switches. According to further aspects of the present invention there is provided a method of forming a fillable volume incorporating the device substantially as described herein, and a fluid tank incorporating such a device. A preferred embodiment of the invention will now be described by way of example only and with reference to the Figures in which: Brief Description of Figures Figure 1 shows an isometric view of an embodiment of the device according to the present invention with the upper control valve open; Figure 2 shows a sectional embodiment of the device according to the present invention, with upper control valve open; Figure 3 shows an isometric view of the embodiment of the device shown in Figure 1, with the upper control valve closed; Figure 4 shows a sectional view of the embodiment of the device according to the present invention with upper control valve closed; Figure 5 shows an exploded isometric view of the embodiment of the device shown in Figure 1; Figure 6 shows a sectional view of the embodiment of the device with an electrical switch, replacing the upper control valve, showing the pump switch on; Figures 7 show a sectional views of an embodiment of the device according to the present invention, with an electrical switch in the off position. Detailed Description of Figures It will be appreciated that aspects, embodiments and preferred features of the invention have been described herein in a way that allows the specification to be written in a clear and concise way. However, unless circumstances clearly dictate otherwise, aspects, embodiments and preferred features can be variously combined or separated in accordance with the invention. Thus, preferably, the invention provides a device having features of a combination of two or more, three or more, or four or more of the aspects described herein. In a preferred embodiment, a device in accordance with the invention comprises all aspects of the invention. Within the context of this specification, the word “substantially” means preferably at least 90%, more preferably 95%, even more preferably 98%, most preferably 99%. Within the context of this specification, the word “comprises” means “includes, among other things” and should not be construed to mean “consists of only”. With reference to Figures 1 to 5, there is shown an embodiment 99 of a volumetric control device for a fluid volume 55, generally comprising: a fluid inlet 4; a first (upper) control valve 1; a second (lower) control valve 8; and a mechanical switch comprising a float 20, between the control valves; wherein the lower control valve controls the mechanical switch, and the upper control valve is controlled by the mechanical switch to open and close the fluid inlet. Float 20 comprises an axial tube having longitudinal first and second ends. A cap is provided at each end. In particular reference to the pictured embodiment shown in Figures 1 to 5, the embodiment comprises an upper control valve 1 having an upper arm 7. Upper arm 7 pivots in a vertical orientation in use and is driven by float 20 moving vertically in use within float chamber 2. The fluid inlet 4 is provided with fluid from a pipe 3 that in the first pictured embodiment extends from outside the volume 55, and provides pressurised water such as from a mains water supply or pump. This fluid fills the volume 55 to a level so that fluid enters an opening 5 defined in the float chamber, where it rapidly fills the float chamber, moves the float 20 and closes the fluid inlet 4 by closing the upper control valve 1. As shown in Figure 2, when the level in the volume 55 falls below the lower control valve 8, the fluid outlet closure means 10 will be opened, the fluid will exit the float chamber 2, and the float 20 will drop and open the upper control valve 1, so as to fill the volume 55 again. At a proximate end of the upper arm 7 there is a closure means 1 for the fluid inlet 4, associated with the pivoting upper arm 7. When the closure means is displaced from the fluid inlet 4 the fluid inlet 4 allows passage of fluid into the volume 55. The upper arm 7 is arranged to travel in a slot 5 in the wall of the cylindrical tubular float chamber 2 which contains the float 20. As shown in Figures 1, 3 and 5, a splash guard 6 is provided on the upper arm 7. The splash guard 6 comprises a generally planar body which defines an opening, through which upper arm 7 projects. Splash guard 6 provides the advantage that splashes or drops of fluid entering the fluid volume 55 through the inlet 4 are deflected from entering slot 5, for example by running down upper arm 7. The slot 5 maintains upper arm 7 in line with the centre of the top of float 20, and acts as an opening defined in the wall of the float chamber 2 for fluid ingress to the float chamber 2 from the volume 55. The bottom of the slot 5 controls where the upper desired level of fluid in the volume 55 will reach. This level determines when the float chamber 2 fills as the fluid enters the chamber 2 through the slot 5. The float chamber 2 has a small bore so will fill rapidly, preventing oscillations in the system. As shown in Figure 4, when the float chamber 2 is full, the float 20 rises and forces the upper arm 7 upwards thereby closing the upper valve 1. In contrast, as shown in Figure 2, when the lower valve is open and the float chamber is drained, the float 20 drops and allows the upper arm to pivot down, thereby opening valve 1 allowing fluid to enter the volume 55 through inlet 4. The slot 5 allows the upper arm 7 movement in a vertical plane, at least the full range of the upper arm 7 operating valve 1, with extra provision at the top end for wear in valve 1 and at the bottom for full valve opening. The upper arm 7 may be envisaged never to touch the top or bottom of the slot 5. As shown in Figures 1 to 5, the pictured embodiment comprises a float chamber 2 provided by a connecting member between the upper control valve 1 and the lower control valve 8. This connecting member is cylindrical and is vertically arranged in use, and contains the float 20 within it, so that around the float there is little space. At the bottom end of the member there is a bend, leading to a spur 13 so as to provide an attachment means 12 for a side of the volume or tank (not shown). Between the bend and the connecting member, is located the lower control valve 8. The lower control valve 8 comprises a ball valve, as known in the art, having a ball 11 and a lower arm 14. The arm 14 has a proximate end adjacent to the connecting member and a distant end. At the proximate end of the arm 14 are provided a pivot and a fluid outlet closure means 10, and at the distant end of the arm 14 is a ball 11. The ball 11 floats on or in the fluid within the volume 55, such that when the fluid level in the volume is below the ball, or more particularly when the closure means is displaced from the fluid outlet of the float chamber 2, the outlet is opened by displacement of the closure means, and fluid flows from the chamber, thereby allowing the float 20 forming the mechanical switch to drop to the chamber’s bottom, and consequently allowing the upper arm 7 to drop towards the bottom of the slot 5. The mechanical switch 20 comprises a length of cylindrical tube, with caps at either end. The outer diameter of the tube may be envisaged to be close to the internal bore diameter of the float chamber 2. The float 20 contacts and drives the upper arm 7 when the float chamber 2 is filled. The longitudinal length of the float 20 may be subject to variation in further embodiments, for example by variation of factors such as material selected for manufacture of the float, length of float chamber or desired upper and lower volume levels. In the pictured embodiments the radial width of the float 20 is substantially identical to the radial width of the float chamber 2. In the pictured embodiments the small volumetric variance between the float 20 and its float chamber 2 results in rapid movement of the float, achieving quick stop and start in any size of tank volume. Fluid enters the float chamber 2 through the slot 5 near the top of the member. When the fluid level is below the lower control valve 8 the fluid outlet allows the member bore to empty, the internal float to drop, and the arm dropping accordingly to allow the upper control valve 1 to open the inlet 4, such that the fluid is let into the volume. When the fluid level is above the lower control valve 8 but below the upper control valve 1, the lower control valve 8 is closed, the chamber outlet is closed, and the upper control valve 1 is open, such that the inlet 4 is open. In this way the volume 55 is enabled to fill until the level of the volume 55 reaches the bottom of the slot 5, when the chamber 2 is filled. When the fluid level in the chamber, is such that the float 20 forces the arm 7 of the upper control valve 1 upwardly, the inlet 4 will be closed. The volume 55 is enabled to be emptied through other means and may be added to only when the level of fluid in the volume 55 is reduced to a level where the lower control valve 8 is opened, thereby rapidly lowering the float 20 and opening the upper control valve 1 and allowing fluid to enter the volume 55 through the inlet 4. This avoids repeated stresses on valves, or control and storage apparatus in general, as well as a continuous reversal of fluid levels and activation of the fluid inlet. With reference to the second pictured embodiment shown in Figures 6 and 7 the upper control valve may be envisaged to be replaced with an electrical switch, for example in relation to water that is pumped into the volume. Examples Tests have been carried out to compare embodiments of a volumetric control device for a fluid volume according to the invention with a known control device. The tests and results are described below. Test 1 A 200 litre tank was fitted with an embodiment of a volumetric control device for a fluid volume according to the invention. The tank was filled with water from a barrel through a fluid inlet under the control of a device according to the invention and a pump having an integral pressure switch. The pump was plugged in via a smart meter plug to measure power consumption of the pump. The pump was stopped by the float switch as soon as the level of water in the tank reached a predetermined upper level (the bottom of the slot, aperture defined in the cylinder of the device). The power used was 190 watts. The test was the repeated with a standard ball float controlling the same inlet valve in place of the device according to the invention. The power used to fill the tank was 190 watts, however at closure the pump stopped and started a further 16 times before finally stopping allowing only a few drops of water through each time. This bouncing effect caused by the slow closure of the valve added a further 56 watts, it was also evident that considerably more wear would occur to all parts of the system through rapid and repeated opening and closing of the inlet valve. Test 2 A tank was fitted with an outlet tap and set to empty at a constant slow rate (attempting to emulate the slow level movement typically experienced with large tanks). A system controlled by a device according to the invention was compared to a separate comparison system controlled by a known ballcock wherein both systems were set to run constantly with the same outflow rate from the tanks both starting with empty tanks. The system controlled by a device according to the invention ran for 5 ½ hours and used 761 watts of energy. The test was stopped just after the 4th filling cycle. The comparison system, which included a tank fitted with a known ballcock and valve was found to fill until the inlet flow reached equilibrium with the outlet flow. In larger systems the pump would be liable to bounce between on and off at this point. At this point in the cycle with a slow outlet, the pump will never pump efficiently. The pump used 900 watts when flat out with an open valve, and after equilibrium was reached the pump used 850 watts when forcing a trickle through a nearly closed valve. Not wishing to burn out a new pump running it against an almost closed valve for 5 ½ hours the energy consumption of filling one tank was measured and the test was stopped. The test revealed that the energy used by the pump for one fill of the tank fitted with a known ballcock and valve was 800 watts. Thereafter, remarkably, the energy used was more than 4 times the energy that the system fitted with a device of the invention used to supply the same outlet flow. Furthermore, given that fluid pumps are known to use a peak energy on starting and energy consumption drops thereafter, by avoiding repeated quick fluctuation between the pump being on and off the invention provides the advantage of significant energy saving, as well as wear on a pump. The volumetric control device for a fluid volume of the invention provides the advantage of a mechanical control system for fluid tanks. Traditional float valves operating in large fluid tanks commonly cause rapid wear to pump parts and valve seals due to slow valve closure. Upper and lower levels of the fluid can be set, and ‘quick stop / start’ achieved by suspending a float chamber within the fluid of the tank. The float chamber is filled from the tank fluid, the movement of a float within the float chamber controls the flow into the tank via an actuating arm operating either pump switches or stop valves. The level of fluid within the float chamber, and thus the movement of the float, is controlled by a ballcock valve at its base. This alternately holds the chamber full or empty, achieving quick stop and start at upper and lower set levels. The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing from the scope of protection as defined by the claims.

Claims

Claims 1. A volumetric control device for a fluid volume, comprising: a fluid inlet to the fluid volume; a body for arrangement in the fluid volume, the body defining a chamber having a float provided therein; a first control valve operable between an open configuration and a closed configuration, the open configuration arranged to open the fluid inlet in response to the float sinking to a first position in the chamber and the closed configuration arranged to close the fluid inlet in response to the float floating to a second position in the chamber; and a second control valve operable between an open configuration and a closed configuration, the open configuration arranged to allow fluid to drain through an outlet from the chamber thereby emptying fluid from the chamber and sinking the float to the first position and the closed configuration arranged to close the outlet thereby holding a column of fluid in the chamber and floating the float in the second position.

2. The volumetric control device for a fluid volume according to claim 1, wherein the first control valve is associated with the fluid inlet and the second control valve is associated with the outlet from the chamber.

3. The volumetric control device for a fluid volume according to claim 2, wherein the outlet from the chamber is located in a lower portion of the chamber in use.

4. The volumetric control device for a fluid volume according to any one of the preceding claims, wherein the first control valve comprises a pivoting float valve.

5. The volumetric control device for a fluid volume according to any one of the preceding claims, wherein the first control valve comprises an arm and the float abuts the arm and exerts a force on it, when the float is in the second position, thereby closing the fluid inlet.

6. The volumetric control device for a fluid volume according to any one of the preceding claims, wherein the first control valve comprises an electrical switch.

7. The volumetric control device for a fluid volume according to any one of the preceding claims, which comprises a pump for pumping fluid into the fluid volume when the first control valve is in the open configuration.

8. A volumetric control device for a fluid volume according to any one of the preceding claims, wherein the body is cylindrical.

9. A volumetric control device for a fluid volume according to any one of the preceding claims, wherein the chamber is cylindrical.

10. A volumetric control device for a fluid volume according to any one of the preceding claims, wherein the float is cylindrical.

11. The volumetric control device for a fluid volume according to any one of the preceding claims, wherein the float comprises a hollow cylinder having a longitudinal axis which is coaxial with a longitudinal axis of the chamber.

12. The volumetric control device for a fluid volume according to any one of the preceding claims, wherein the body has a longitudinal axis which is arranged vertically in use.

13. The volumetric control device for a fluid volume according to any one of the preceding claims, wherein an opening for fluid ingress into the chamber is defined in an upper portion of the chamber in use.

14. The volumetric control device for a fluid volume according to any one of the preceding claims, wherein the first control valve comprises an arm and a longitudinal slot is defined in a wall of the body for passage of the arm.

15. The volumetric control device for a fluid volume according to claim 12, which includes a splash guard which comprises a generally planar body which defines an opening, through which the arm projects.

16. The volumetric control device for a fluid volume according to any one of the preceding claims, wherein the second control valve comprises a float valve.

17. Apparatus comprising a device according to any of the preceding claims, and a tank providing the fluid volume.

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