GB2074706A - Float controlled draw off tube for hot water storage tank - Google Patents

Abstract

A warm water tank 11 has a valve arrangement 50 comprising an extensible tube having two tube sections, namely a flexible tube section 53 (e.g. of corrugated hose) and a rigid tube section which is closed off at one end, where it has a thread 26 for connection to a weight 27 in a float 25, and which also has an outlet 30 to allow water from the tank 11 to flow through the rigid tube section, the tube section 53 and a subsequently connected flow-off pipe 51. The outlet 30 is normally below the level of water in the tank 11. As the level of water falls the float 25 falls with it, to keep the outlet 30 below the water, since the tube section being flexible can be displaced to coil round the tank's innerside. Instead of two tube sections there may be four rigid tube sections telescopically slidable within one another. <IMAGE>

Description

SPECIFICATION Valve arrangement This invention relates to a valve arrangement for use in a warm water tank connected between a cold water tank and a hot water tank, the warm water tank being heatable, for example, by the incorporation of a heating coil to which is supplied water heated by a solar collector.

With such warm water tanks it is desirable to extract the warmest water possible therefrom and conduct it to the hot water tank.

Since, in the warm water tank, the hottest water is at the top of the tank this necessitates an outlet from the tank to be positioned near the top. One disadvantage of this is that, when the outlet becomes exposed, through withdrawal of water, air can be entrained into the hot water tank which is detrimental to its efficient operation.

An object of the invention is to provide an improved valve arrangement for use in such a warm water tank.

Accordingly the invention provides a valve arrangement, for use in a warm water tank conected between a cold water tank and a hot water tank, comprising an extensible tube having a plurality of tube sections, one end section of the tube being connected to a float and having a hot water outlet for drawing off water from the warm water tank, and the other end section of said tube being connected to a flow-off pipe, the tube sections being adapted for mounting in the warm water tank with the float uppermost such that when the float falls with a fall in the water level in the warm water tank the tube sections can be so displaced relative to one another and/or to the warm water tank, that the hot water outlet in said one end section remains Icst below the water level.

Advantageously, the tube comprises either two tube sections or four tube sections.

Where the tube comprises two tube sections the one end section of the tube may be rigid and the other end section may be flexible.

The other end section may be a corrugated hose, which is of greater length than the one end section, enabling said other end section to coil round the warm tank's innerside as the heat falls with a fall in the water level.

Where the tube comprises four tube sections, the tube sections may be of equal lengths but different diameters, the tube sections being arranged vertically in the tank such that one respective tube is slidable tele scopically in another respective tube. Preferably, each of the four tube sections is rigid.

Whether the tube comprises two tube sections or four tube sections said one end section of the tube preferably has a solid portion, the solid portion closing off the one end section and advantageously having a screw thread and extending through an aperture in the float's lower half so as to engage a weight in the float's interior.

Preferably, the float when viewed in plan is a slightly smaller diameter than the warm water tank's interior diameter. When viewed in vertical cross-section the float is substantially a flattened oval shape.

This invention will be described further, by way of example, with reference to the accompanying drawings the following description being illustrative and restrictive, of the scope of the invention.

In the drawings: Figure 1 is a cross-sectional elevation of a first preferred embodiment of the valve arrangement of the invention; and Figure 2 is a cross-sectional elevation of a second preferred embodiment of the valve arrangement of the invention.

The first preferred embodiment of the valve arrangement, generally denoted by the reference numeral 10, and the second preferred embodiment of the valve arrangement of the invention, generally denoted by the reference numeral 50, are each disposed in a substantially cylindrical warm water tank 11 arranged between a rectangular cold water tank 1 2 and a hot water tank (not shown). The warm water tank 11 is heatable by means of a heating coil 13, to which is supplied water heated by a solar collector (not shown), and has a draw-off pipe 14 at its base for supplying water to the hot water tank. The tank 11 also has on its outside a layer of insulation material 1 5 made of polypropylene which is applied to the tank 11 during its manufacture. Alternatively, insulation for the tank 11 may be provided by a conventional jacket or by lagging.

The tank 1 2 is considerably smaller than the tank 11 and is secured to the tank 11 by means of a bracket 1 6 having a downturned lip 1 7b which engages over the top edge of the tank 11. Alternatively, that wall of the tank 1 2 which is immediately adjacent the curved outer surface of the tank 11 may have the same shape as said surface, but curving inwards to provide a compact arrangement of warm water tank 11 and cold water tank 1 2.

In this case, where the two tanks 11 and 1 2 are made of the same material, for example plastics, they could be moulded in one piece.

Water from the tank 1 2 is supplied to the tank 11 by means of a pipe 1 8 which is threaded at one end 37 to enable it to be connected to the base of the tank 1 2 by means of nuts 38. The pipe 18 is also threaded at its other end 39 to enable it to be connected to the base of tank 11 by means of nuts 40. The pipe 1 8 has a trap or U-bend 1 9 to prevent water from the tank 1 2 from flowing back to the tank 11. The tank 11 has a dome-shaped lid 20, not only to allow ventilation of the tank 11 but also to prevent dust from entering and contaminating the water.

Although water regulations require that the cold water tank 1 2 shall conform to minimum capacity requirement, it will be appreciated that the foregoing combination of cold water tank ii and warm water tank 11 provides a very compact arrangement. The cold water tank 1 2 will at least meet minimum gallonage regulations required of a cold water tank feeding a warm water tank. This also ensures that there will be a constant head of pressure through the two tanks as the water level drops.

Referring specifically now to Fig. 1, the first preferred embodiment of the valve arrangement 10 comprises an extensible hollow tube disposed vertically in the warm water tank 11 and consisting of four tube sections 21, 22, 23, 24 substantially equal in length but each of a different diameter. The tube sections 21, 22, 23, 24 are made, for example, of a rigid plastics material or mild steel and are connected with one another, such that they can slide together telescopically. One end section 24 is connected to a float 25 and the other end section 21 is connected to the flow-off pipe 14. The tube section 21 is slidable in the flow-off pipe 14, this being facilitated by the outer diameter of the tube section 21 corresponding to the inner diameter of the flow-off pipe 14.Similarly, the tube section 22 is slidable in a corresponding manner in the tube section 21, the tube section 23 is slidable in a corresponding manner in the tube secton 22, and the tube section 24 is slidable in a corresponding manner in the tube section 23.

That end of each of tube sections 21 to 23 which faces towards the float 25 has an inwardly extending flange 41 while that end of each of tube sections 21 to 23 which faces towards the flow-off pipe 14 has an outwardly extending flange 42. When the tube is fully extended the flange 41 of one tube section will abut the flange 42 of an adjacent tube section preventing the tube sections 21 to 23 from sliding out of one another. Of course tube sections 21 is only provided with an outwardly extending flange 42 and the flowoff pipe with an inwardly extending flange 41.

It will also be appreciated that when the tube sections 21, 22, 23, 24 slide fully one within another they provide a compact arrangement having a length which is equal to the length of a single tube section.

To enable the tube section 24 to be connected to the float 25, said tube section 24 has a solid portion at one end thereby closing it off, this solid portion having a thread 26 and extending through an aperture in the float's lower half where it is secured by means of a nut 43 and a washer 44. A portion of the thread 26 extends beyond the nut 43 so that a weight 27 can be secured thereto.

The float 25 is made, for example, of a plastics material. When viewed in plan the float 25 is round, although is substantially a flattened oval shape when viewed in vertical cross-section, and has a diameter which is slightly less than the internal diameter of the tank 11. This allows the float 25 to rise and fall with the water level in the tank 11 without it touching the tank's innerside. The float 25 has on its upper half a circular cap ir lid 28 having an aperture 29 to allow air into the float's interior when the lid 28 is in position on the float 25. The lid 28 snap fits over an upturned lip of a correspondingly shaped hole in the float 25. The lid 28, of course, allows access to the interior of the float 25 or any other form of ballast.The float 25 also provides further insulation for the tank 11 in that it prevents heat loss from the water, particularly by evaporation, since it covers virtually the entire surface of the water.

The tube section 24 has a hot water outlet 30, for water in the tank 11 adjacent that end thereof which has the thread 26 and is secured to the float 25. Since this outlet 30 is just below the water level in the tank 11 it allows an inflow of water from the tank 11 into the tube section 24 and subsequently into tube sections 23, 22, 21 and the flow-off pipe 14 respectively.

Also secured to that end of the tube section 24 which has the thread 26 is a cylindrical collar 31 forming a chamber 32 surrounding the aforesaid end of the tube section 24 and having a downwardly facing opening. The collar 31 has an internal cylindrical boss 33 which has a passage 34 which communicates with the outlet 30. The collar31 is secured against the underside of the float 25 by means of a nut 45 and a washer 46. The nut 45 engages that portion of the th read 26 which extends beyond the boss 33. As an alternative to the nut 45 and washer 46 the collar 31 could be integral with the tube section 24. The collar 31 prevents air accidentally entering the outlet 30 due, for example, to disturbance of the water in the tank 11 upon movement of the float 25. Additionally, the collar 31 is provided with air vents 35 to allow any air which manages to become trapped in the chamber 32 to escape.

Referring now to Fig. 2, the second preferred embodiment of the valve arrangement 50 of the invention also comprises the tube section 24, which is connected to the float 25 and which is slightly shorter at its open end than in the valve arrangement 10. Projecting upwardly from the bottom of the tank is an inverted L-shaped flow-off pipe 51. Connected between the tube section 24 and the flow-off pipe 51, by means of a respective pair of friction couplings 52, is a flexible tube section 53. The tube section 53 is a corrugated hose made, for example, of plastics and of a substantially greater length than the tube section 24.

In both Fig. 1 and Fig. 2 the position of the float 25 is shown when the tank 11 is full of water. As the outlet 30 is just below the water level in the tank 11 it draws in water and the water level in the tank 11 begins to fall. With the valve arrangement 10, as the water level begins to fall so the float 25 also begins to fall since the tube sections 21, 22, 23, 24 slide together telescopically, one within another. With the valve arrangement 50, as the water level begins to fall the float 25 also begins to fall since the tube section 53 being corrugated hose and thereby flexible is made to coil round the innerside of the lower half of the tank 11. To further facilitate the fall of the float 25 with the water level, the weight 27 is ideally made of a heavy material such as lead.

Therefore, both with the valve arrangement 10 and valve arrangement 50 the outlet 30 always remains just below the water level in the tank 11 so that it is not exposed to air which remains in the tank 11 above the water as the water level falls. Furthermore, since the inflow of water into the outlet 30 is always the uppermost layer of water in the tank 11 then the warmest water possible always flows to the hot water tank. Of course, when the water in the tank 11 falls to a certain level it will be topped up by water from the tank 1 2 which is provided with a conventional ball valve arrangement 36.

To facilitate the maintenance of the interior of the tank 11, and also to ensure the free movement of the float 25, the lower portion of the tank 11 has a greater diameter than the upper portion of the tank 11. This ensures that the diameter of the heating coil 1 3 is greater than the diameter of the float 25 so that the float 25 can move freely past the heating coil 1 3 when the tank is drained or when the water level in the tank is low.

Alternatively, however, the warm water tank may have the same diameter along its entire length. In this instance the heating coil 1 3 can be positioned nearer the bottom of the tank than it is positioned in the described and illustrated tank 11. Some means may be provided, for example brackets, to engage the float 25 just above the heating coil 13, so that said float 25 never comes in contact with the heating coil 1 3. As shown in Fig. 2, the tank 11 can be provided with a pipe 47 for delivering hot water from the solar panel directly into the tank 11 in addition to or instead of to the solar heating coil 1 3. The pipe 47 extends through a hole in the lid 20 near the edge of the float 25. At its end 48 the pipe 47 is splayed to ensure that the water runs smoothly and uniformly therefrom.

Claims (9)

1. A valve arrangement, for use in a warm water tank connected between a cold water tank and a hot water tank, comprising an extensible tube having a plurality of tube sections, one end section of the tube being conected to a float and having a hot water outlet for draining off water from the warm water tank, and the other end section of said tube being connected to a flow-off pipe, the tube sections being adapted for mounting in the warm water tank with the float uppermost such that when the float falls with a fall in the water level in the warm water tank the tube sections can be so displaced relative to one another, and/or to the warm water tank, that the hot water outlet in said one end section remains just below the water level.

2. A valve arrangement as claimed in claim 1 wherein the tube comprises two tube sections.

3. A valve arrangement as claimed in claim 1 wherein the tube comprises four tube sections.

4. A valve arrangement as claimed in claim 1 or claims 1 and 2 wherein the one end section of the tube is rigid and the other end section of the tube is flexible.

5. A valve arrangement is claimed in claim 1, 2 or 4 wherein the other end section is a corrugated hose, which is of greater length than the one end section, enabling said other end section to coil round the warm water tank's innerside as the float falls with a fall in the water level.

6. A valve arrangement as claimed in claim 3 wherein the four tube sections are of equal lengths but different diameters, the tube sections being arranged vertically in the tank such that one respective tube is slidable in another respective tube.

7. A valve arrangement as claimed in claim 6 wherein each of the four tube sections is rigid.

8. A valve arrangment as claimed in any preceding claim wherein said one end section of the tube has a solid portion, the solid portion closing off the tube and having a screw thread and extending through an aperture in the float's lower half so as to engage a weight in the floats interior.

9. A valve arrangement as claimed in any preceding claim wherein the float when viewed in plan is round and is slightly smaller in diameter than the warm water tank's interior diameter and when viewed in vertical cross-section is substantialy a flattened oval shape.

1 0. A valve arrangement substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.