GB2415487A

GB2415487A - Unvented water heater

Info

Publication number: GB2415487A
Application number: GB0414207A
Authority: GB
Inventors: Christopher Samuel Powell; Michael Roy Hales
Original assignee: FABDEC Ltd; Baxi Heating UK Ltd
Current assignee: Baxi Heating UK Ltd
Priority date: 2004-06-24
Filing date: 2004-06-24
Publication date: 2005-12-28
Anticipated expiration: 2024-06-24
Also published as: GB0414207D0; GB2415487B

Abstract

The water heater has a tank with a domed upper end 2. An axially downwardly extending outlet pipe 4 is located in the tank and terminates at a level above a cold water inlet pipe 6. A buoyant convex baffle 10 is slidably mounted on the outlet pipe via a central tubular portion 12. A disc-shaped stop 8 is provided on the lower end of the outlet pipe to prevent the baffle descending below the level of the inlet pipe. The baffle is shaped to match the domed upper end 2 and includes a planar rim 14 at its edge and an open underside. The baffle floats on the surface S of the water and can rise above the level of the stop while preventing a volume of air above the baffle being absorbed into the water.

Description

24 5487

WATER HEATERS

This invention relates to unvented water heaters.

It is known to arrange for an unvented water heater to contain a volume of air between the water level and the top of the tank to accommodate expansion of the water in the tank as it is heated. A system incorporating this arrangement has the advantage that it does not require an external expansion tank. However, the possibility exists that the air at the top of the tank is absorbed by the water and is gradually lost. Patent No. EP 0 592 222 discloses the use of a baffle in the upper region of the tank to limit or prevent the absorption of air by the water.

Several of the baffles disclosed in the above-mentioned patent are fixed in position within the tank and therefore do not prevent the water in the tank coming into contact with the volume of air at its top. Other embodiments of came are arranged to float on the water surface and thereby improve the separation of the volume of air from the water surface.

In one such embodiment the baffle is in the form of a flat disc made from a material capable of floating on water. In another, the baffle is designed so that it could be made from metal or another material more dense than water. In this construction the baffle is hollow so as to provide buoyancy. The construction of this latter type of baffle is therefore relatively complicated.

To overcome this disadvantage the present invention provides an unvented waterheating tank with a baffle which is of domed or generally convex construction capable of retaining a body of air between it and the water surface and thereby providing the baffle with the necessary buoyancy.

The drawing shows a vertical axial section through the upper part of a hot water tank incorporating a baffle in accordance with the invention. Referring to the drawing a hot water tank generally as described and illustrated in Patent No. EP 0 592 222 has a domed upper end 2 provided with an axially extending hot water outlet pipe 4. The outlet pipe terminates at - 2 a level above a cold water inlet pipe 6. The lower end of the outlet pipe is provided with a disc-shaped stop 8. A baffle 10 is of convex shape, open to its underside and having a downwardly extending tubular portion 12 at its centre which is slidable on the outlet pipe.

The baMe has a planar radically extending rim 14 at its edge, having an outer diameter slightly less than the inner diameter of the tank. The shape of the convex portion of the baffle is such as to match the upper end of the tank and allow increased upward movement of the baffle so prolonging the air gap.

In use, the volume of air A beneath the baffle allows the baffle to float on the surface S of the water when this rises above the level of the stop. However, the stop prevents the baffle descending below this level and interfering with the flow of water into the tank. The volume of air above the baffle cannot be absorbed into the water below the baffle and therefore provides the necessary resilience when the water level rises. 3

Claims

CLAIM

An unvented water heater comprising a tank having an outlet pipe extending downwardly into the tank, a baffle slidable on the outlet pipe, the outlet pipe having a stop to limit downwards movement of the baffle, the baffle being shaped to retain a volume of air between it and the water surface so as to provide buoyancy.

Amendments to the claims have been filed as follows 1. An unvented water heater comprising a tank having an outlet pipe extending downwardly into the tank, a bame slidable on the outlet pipe, the outlet pipe having a stop to limit downwards movement of the baffle, the baffle being shaped to retain a volume of air beneath the baffle and in contact with the water surface so as to provide buoyancy to the baffle.
2. A water heater as claimed in Claim 1, wherein the baffle is of domed or generally l O convex construction.
3. A water heater as claimed in Claim 2, where the baffle generally corresponds in shape to the shape of the upper end of the tank.
4. A water heater substantially as hereinbefore described with reference to and as illustrated in the drawing.