GB2186678A

GB2186678A - Expansion vessel

Info

Publication number: GB2186678A
Application number: GB08700250A
Authority: GB
Inventors: Vincent Thomas Armstrong
Original assignee: PRESSURE UNITS Ltd
Current assignee: PRESSURE UNITS Ltd
Priority date: 1986-02-14
Filing date: 1987-01-07
Publication date: 1987-08-19
Anticipated expiration: 2007-01-07
Also published as: GB2186678B; GB8603642D0; GB8700250D0

Abstract

An expansion vessel for a central heating system adapted to be included between water heating plant and a pressurised water supply, has a port (18) at its lower end for connection with said water supply and pipe means (14) for feeding water displaced from the system or returning water to the system which pipe means has an open end (15) in an upper part of the vessel (10) directed upwardly towards the top of the vessel. <IMAGE>

Description

SPECIFICATION Expansion vessel This invention concerns an expansion vessel for use in a medium to large central heating system employing heated water as a heat exchange medium.

It is known that the water displaced from such a system as a result of thermal expansion may be of substantial volume and that its storage in an insulated reservoir for subsequent recovery can result in significant energy saving.

Vessels in the form of vertically extending tanks having upper and lower opposed ports connected to the water heating plant and pressurised water supply means respectively, are known. Their purpose has been to store heated water displaced from the system for subsequent return. It has been found, however, that there has been a tendency for preferential flow directly between the opposed ports leaving the main body of water in the vessel substantially static thus limiting the effective capacity of the vessel as a reservoir for heated water to be retained for subsequent return.

One possible solution is proposed in British Specification No. 2149080 wherein means is included within the vessel to ensure vertical laminar flow substantially over the whole cross-sectional area of the vessel. Such means may take the form of vertically extending baffle plates or axially spaced perforated grids, and is designed to break the flow of water through the vessel between the ports in either direction into a multiplicity of adjacent vertically extending layers or streams so that the last-that is most heated-water to enter the vessel is retained at the head of the vessel to be available for return.

Such vessels are relatively costly on account of the provision of such internal means.

It is an object of the present invention to provide an expansion vessel which overcomes, at least to some extent, the problems aforesaid.

According to the present invention there is provided an expansion vessel for a central heating system adapted to be included between water heating plant and a pressurised water supply, having a port at its lower end for connection with said water supply and pipe means for feeding water displaced from the system or returning water to the system which pipe means has an open end in an upper part of the vessel directed upwardly towards the top of the vessel.

The pipe means may extend vertically through the vessel from the base thereof or comprise a portion of L or U-shape one of whose limbs exits the vessel through the side or top thereof respectively.

The vessel may be thermally insulated.

The invention also includes a central heating system incorporating an expansion vessel as aforesaid.

The invention will be further apparent from the following description with reference to the several figures of the accompanying drawings, which show, by way of example only, a number of expansion vessels embodying same.

Of the drawings: Figure 1 shows a vertical cross-section through a first form of expansion vessel; and Figures 2 and 3 show fragmentary vertical sections through second and third forms of expansion vessel.

Referring firstly to Fig. 1, it will be seen that the expansion vessel comprises a cylindrical tank 10 having upper and lower domed ends 11 and 12 respectively. A pipe 13 adapted to be connected to that part of a central heating system including the water heating plant enters the tank 10 through is lower end 12 and connects with an upstanding portion 14 extending vertically within the tank 10 along the central axis thereof and whose open upper end 15 is directed towards the underside of the upper domed end 11.

A further pipe 16 adapted to be connected to a pressurised water supply enters a jacket 17 surrounding that portion of pipe 13 entering the tank 10 and providing an annular communication port 18 coaxial with portion 14 between pipe 16 and the interior of tank 10 at the base thereof.

In use water displaced from the system through thermal expansion is driven through pipe 13 and portion 14 to enter the upper part of tank 10. The heated water acts like a piston displacing cold water downwardly to exit tank 10 through port 18 and pipe 16.

Tank 10 is enclosed within an insulating jacket 20 whereby heated water contained therein is maintained at a high temperature. Whenever there is demand for water to return to the system it is drawn from the head of tank 10 through portion 14 and pipe 13. Thus heated water displaced is stored for return minimising thermal wastage.

It wil be appreciated that it is not intended to limit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible, without departing from the scope thereof.

Thus, for example, as shown in Fig. 2 pipe 13 may enter the side of tank 10 to connect with an L-shaped portion whose open end is directed upwardly towards the upper domed end 11 of tank 10.

Again, as shown in Fig. 3 pipe 13 may enter the upper domed end 11 of tank 10 to connect with a U-shaped portion 40 whose open end is directed upwardly towards the underside of the end 11.

1. An expansion vessel for a central heat

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Expansion vessel This invention concerns an expansion vessel for use in a medium to large central heating system employing heated water as a heat exchange medium. It is known that the water displaced from such a system as a result of thermal expansion may be of substantial volume and that its storage in an insulated reservoir for subsequent recovery can result in significant energy saving. Vessels in the form of vertically extending tanks having upper and lower opposed ports connected to the water heating plant and pressurised water supply means respectively, are known. Their purpose has been to store heated water displaced from the system for subsequent return. It has been found, however, that there has been a tendency for preferential flow directly between the opposed ports leaving the main body of water in the vessel substantially static thus limiting the effective capacity of the vessel as a reservoir for heated water to be retained for subsequent return. One possible solution is proposed in British Specification No. 2149080 wherein means is included within the vessel to ensure vertical laminar flow substantially over the whole cross-sectional area of the vessel. Such means may take the form of vertically extending baffle plates or axially spaced perforated grids, and is designed to break the flow of water through the vessel between the ports in either direction into a multiplicity of adjacent vertically extending layers or streams so that the last-that is most heated-water to enter the vessel is retained at the head of the vessel to be available for return. Such vessels are relatively costly on account of the provision of such internal means. It is an object of the present invention to provide an expansion vessel which overcomes, at least to some extent, the problems aforesaid. According to the present invention there is provided an expansion vessel for a central heating system adapted to be included between water heating plant and a pressurised water supply, having a port at its lower end for connection with said water supply and pipe means for feeding water displaced from the system or returning water to the system which pipe means has an open end in an upper part of the vessel directed upwardly towards the top of the vessel. The pipe means may extend vertically through the vessel from the base thereof or comprise a portion of L or U-shape one of whose limbs exits the vessel through the side or top thereof respectively. The vessel may be thermally insulated. The invention also includes a central heating system incorporating an expansion vessel as aforesaid. The invention will be further apparent from the following description with reference to the several figures of the accompanying drawings, which show, by way of example only, a number of expansion vessels embodying same. Of the drawings: Figure 1 shows a vertical cross-section through a first form of expansion vessel; and Figures 2 and 3 show fragmentary vertical sections through second and third forms of expansion vessel. Referring firstly to Fig. 1, it will be seen that the expansion vessel comprises a cylindrical tank 10 having upper and lower domed ends 11 and 12 respectively. A pipe 13 adapted to be connected to that part of a central heating system including the water heating plant enters the tank 10 through is lower end 12 and connects with an upstanding portion 14 extending vertically within the tank 10 along the central axis thereof and whose open upper end 15 is directed towards the underside of the upper domed end 11. A further pipe 16 adapted to be connected to a pressurised water supply enters a jacket 17 surrounding that portion of pipe 13 entering the tank 10 and providing an annular communication port 18 coaxial with portion 14 between pipe 16 and the interior of tank 10 at the base thereof. In use water displaced from the system through thermal expansion is driven through pipe 13 and portion 14 to enter the upper part of tank 10. The heated water acts like a piston displacing cold water downwardly to exit tank 10 through port 18 and pipe 16. Tank 10 is enclosed within an insulating jacket 20 whereby heated water contained therein is maintained at a high temperature. Whenever there is demand for water to return to the system it is drawn from the head of tank 10 through portion 14 and pipe 13. Thus heated water displaced is stored for return minimising thermal wastage. It wil be appreciated that it is not intended to limit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible, without departing from the scope thereof. Thus, for example, as shown in Fig. 2 pipe 13 may enter the side of tank 10 to connect with an L-shaped portion whose open end is directed upwardly towards the upper domed end 11 of tank 10. Again, as shown in Fig. 3 pipe 13 may enter the upper domed end 11 of tank 10 to connect with a U-shaped portion 40 whose open end is directed upwardly towards the underside of the end 11. CLAIMS

1. An expansion vessel for a central heat ing system adapted to be included between water heating plant and a pressurised water supply, having a port at its lower end for connection with said water supply and pipe means for feeding water displaced from the system or returning water to the system which pipe means has an open end in an upper part of the vessel directed upwardly towards the top of the vessel.

2. An expansion vessel according to claim 1 wherein said pipe means extends vertically through the vessel from the base thereof.

3. An expansion vessel according to claim 2 wherein said pipe means is surrounded by an annular aperture in the base of the vessel which aperture is connected with the pressurised water supply.

4. An expansion vessel according to claim 1 wherein said pipe means comprises a portion of L-shape one of whose limbs exits the vessel through a side wall thereof.

5. An expansion vessel according to claim 1 wherein said pipe means comprises a portion of U-shape one of whose limbs exits the vessel through the top thereof.

6. An expansion vessel according to any preceding claim and which is theremally insulated.

7. A central heating system including an expansion vessel according to any preceding claim.

8. An expansion vessel substantially as described herein with reference to and as illustrated by Fig. 1 of the accompanying drawing.