GB2241564A - Domestic water heating boilers - Google Patents

Abstract

A domestic water heating boiler, for example of the "instant" type, comprises a casing enclosing the heat exchangers, expansion tank, control valve, pump and other components. The boiler components are interconnected by fluid flow conduits 10 and a major proportion of the conduits 10 are mounted on a rear structural panel 11 of the casing. The conduits 10 are located on one side of the panel 11 and the boiler components 17, 18 are mounted on the other side, the conduits being connected to the components by connectors 13 which pass through apertures in the panel. The connectors 13 serve also to mount the conduits 10 and components 17, 18 on the panel 11. This arrangement may provide a very compact assembly which is easy to manufacture and where the boiler components are readily accessible for servicing. <IMAGE>

Description

"Improvements in or relating to water heating boilers" The invention relates to water heating boilers and in particular to domestic boilers of the kind used to provide hot water for central heating and for domestic use. The invention is particularly, but not exclusively, applicable to boilers of the so-called "instant" type in which primary water is heated and supplied to a central heating circuit, hot water for domestic use being provided by passing cold secondary water through a heat exchanger in the boiler where the secondary water is heated by heat exchange with the primary water.

Such boilers are particularly suitable for use in small dwellings where the demand for heating and hot water is comparatively modest. Accordingly, it is also desirable that such boilers should be as compact in size as possible, while still allowing ease of servicing and ease of manufacture.

It'hays been proposed, as disclosed in European Patent Specification No. 0268564, that a compact design for such a boiler may be facilitated by integrally forming the necessary fluid flow conduits in a structural wall member of the boiler casing or frame.

Thus, the wall member consists of two sheets of metal, one or both of the sheets being deformed to provide channels so that when the two sheets are welded together face-to-face the channels form enclosed conduits between the two sheets. The operative boiler components, i.e.

the heat exchanger, pump, expansion tank, control valve etc., are placed in communication with the conduits by connectors which are secured to one or other of the metal sheets and communicate with the interior of the conduits.

While such a form of construction may meet the requirements of compactness of design and ease of servicing of components, it may not be particularly easy to manufacture to the required quality, particularly on a mass production basis. The present invention therefore sets out to provide an alternative form of construction for water heating boilers which may also provide advantages of compact design and ease of access to the components for servicing, but which may also allow rapid and simple assembly, for mass production in a manufacturing plant, while maintaining reliability and facilitating quality control.

The invention is based on the concept of providing all or most of the fluid flow conduits on a single panel, but providing the conduits as separate components which are mounted on the panel, rather than being incorporated within its structure as proposed in European Specification No. 0268564.

According to the invention, therefore, there is provided a water heating boiler of the kind comprising a casing enclosing a plurality of operative boiler components interconnected by fluid flow conduits wherein at least a major proportion of said conduits are mounted on a panel so as to extend across the surface thereof.

There may be provided a plurality of fluid flow connectors connecting said operative boiler components to said conduits, and at least certain of said connectors may also include means mounting said conduits on the panel.

Preferably at least some of said operative boiler components are located on the opposite side of the panel to the conduits to which they are connected, said connectors providing a flow path through the panel.

For example, each connector may pass through an aperture in the panel as it extends between a component and a conduit.

Each connector may comprise a generally tubular spigot passing through an aperture in the panel and communicating with the interior of a conduit, means being provided for holding the spigot to the panel. In one particular embodiment, the tubular spigot includes two portions of different cross dimensions providing a shoulder between them, the smaller portion passing through an aperture in the panel so that the shoulder abuts one side face of the panel, holding means being provided to engage the smaller portion of the connector and abut the opposite side face of the panel. At least the smaller portion of the spigot may be circular in cross section, in which case the holding means may comprise a circlip engaging within an annular groove formed around the periphery of the spigot adjacent said opposite side face of the panel.

Preferably substantially all the conduits are located on one side of the panel and substantially all the operative boiler components are located on the other side of the panel.

The boiler casing will normally include a removable portion to provide access to the interior of the casing, and to the boiler components, and in this case the side of the panel on which the components are located preferably faces said removable portion.

Said operative boiler components may include some or all of the following components: a primary heat exchanger, a secondary heat exchanger, an expansion tank or accumulator, a control valve, such as a three-way valve, for controlling the flow of fluid between said components and through said conduits, an electric pump, and an air vent valve.

Preferably the panel also constitutes a structural element of the boiler casing and contributes to the structural strength thereof.

As previously mentioned, the invention is particularly applicable to so-called "instant" type boilers, but is not limited to such application and may provide a convenient and compact structural arrangement for other types of boiler.

The following is a more detailed description of embodiments of the invention, reference being made to the accompanying drawings in which: Figure 1 is a diagrammatic front view of the back panel of a water heating boiler in accordance with the invention, Figure 2 is a section on the line 2 - 2 of Figure 1, Figure 3 is a section on the line 3 - 3 of Figure 1, Figure 4 is a section through one form of connector for connecting a boiler component to a conduit, and also for mounting the conduit on a panel, and Figure 5 is a plan view of the connector of Figure 4 and the conduit to which it is connected.

Figures 1-3 show a back panel for a domestic water heating boiler of the kind used to provide hot water for central heating and for domestic use. The boiler may be of the so-called "instant" type in which primary water is heated for supply to a central heating circuit, hot water for domestic use being provided by passing cold secondary water through a heat exchanger in the boiler where the secondary water is heated by heat exchange with the primary water. The boiler thus comprises a number of operative boiler components interconnected by fluid flow conduits, such components normally comprising a primary heat exchanger, a secondary heat exchanger, an expansion tank or accumulator, a three-way fluid control valve and an electric pump, all such components being contained within a casing together with any other elements necessary for operation of the boiler.The primary water may be heated by a gas burner in the primary heat exchanger, the secondary water being heated, in the secondary heat exchanger, by heat exchange from the heated primary water. In some types of boiler, however, both the primary and secondary water are heated in a single combined heat exchange assembly. The particular nature of the operative boiler components, and their arrangement within the casing, do not form a part of the present invention and will, in any case, be well known to those skilled in the art. Such details of the boiler will not therefore be described in detail.

As previously mentioned, the present invention concerns the arrangement and mounting within the casing of the fluid flow conduits for interconnecting the various boiler components.

In the arrangements shown in the drawings, the conduits 10 are separately pre-formed pipes which are all mounted on a rectangular sheet metal panel 11 having side flanges 12. The panel 11 preferably forms a structural part of a rectangular casing and may, for example, constitute the back panel of the casing.

The pipes 10 extend across the rear surface of the panel 11 and are in fluid flow connection at their ends with various connectors 13. Each connector 13 is in the form of a tubular spigot having a reduced diameter portion 14 which passes through a correspondingly sized aperture in the panel 11 so that the shoulder between the two portions of the spigot abuts the rear surface of the panel. A circlip engages within an annular groove formed around the periphery of the smaller part of the spigot adjacent the front face of the panel 11 to secure the connector in position.

The bore 15 in the part of the connector which projects through the panel communicates with a transverse blind bore 16 with which the end of the pipe 10 is connected.

Any conventional means may be used for securing the ends of the pipe 10 to the connectors, such as brazing.

Figure 1 shows the arrangement of pipes 10 and connectors 13 for a typical boiler construction and Figures 2 and 3 show diagrammatically, by way of example, an electric pump 17 and a diverting valve 18 (in exploded view) having couplings disposed for fluidtight connection with the appropriately located connectors 13.

In the manufacturing process, appropriately shaped and dimensioned lengths of pipe 10 have the appropriate connectors 13 brazed to their ends and each assembly of pipes and connectors is then offered up to the rear surface of the panel 11 so that the smaller diameter portions of the connectors can be passed through the corresponding apertures in the panel 11 and the circlips fitted to secure the connectors, and hence the pipes in position. The boiler components, such as the pump 17 and valve 18, are then coupled to the protruding portions of the connectors, using conventional fluid-tight coupling devices.

The panel 11 and pipes 10 may thus be preassembled to form a convenient unit for assembly with the rest of the boiler components in the casing. Since the boiler components are substantially all then mounted on the front side of the panel 11 they are easily accessible, not only for initial assembly of the boiler, but also for servicing at a later date. The casing normally has a removable door panel to provide access to its interior and such panel will therefore normally be opposite the front surface of the back panel 11 so as to provide access to the components mounted on the panel.

Since each assembly of a pipe 10 and associated connectors 13 is pre-assembled before mounting on the panel 11, quality control is facilitated and it can be ensured that the junctions between the pipes and the connectors are fluid-tight.

Figures 4 and 5 show on an enlarged scale another form of connector for connection to an intermediate portion of a pipe 10.

In this case the connector 19 is in the form of a tubular spigot having a reduced diameter portion 20 which passes through an aperture in the panel 11 so that the shoulder between the two parts of the spigot abuts the rear surface of the panel. A circlip 21 is received in a an annular peripheral groove in the smaller diameter portion of the spigot and abuts the front surface of the panel 11 to secure the connector 19 firmly to the panel.

The larger diameter portion of the connector is formed with a part-cylindrical transverse recess 22 in which the pipe 10 is brazed. The central bore 23 in the connector then communicates with a circular hole 24 in the pipe 10. The portion of the connector which projects to the front side of the panel 11 receives an 0-ring 25 and is shaped to cooperate with an appropriate coupling on the particular boiler component which is to be coupled to the connector.

Claims (11)

1. A water heating boiler of the kind comprising a casing enclosing a plurality of operative boiler components interconnected by fluid flow conduits wherein at least a major proportion of said conduits are mounted on a panel so as to extend across the surface thereof.

2. A water heating boiler according to Claim 1, wherein there are provided a plurality of fluid flow connectors connecting said operative boiler components to said conduits, and wherein at least certain of said connectors include means mounting said conduits on the panel.

3. A water heating boiler according to Claim 2, wherein at least some of said operative boiler components are located on the opposite side of the panel to the conduits to which they are connected, said connectors providing a flow path through the panel.

4. A water heating boiler according to Claim 3, wherein each connector passes through an aperture in the panel as it extends between a component and a conduit.

5. A water heating boiler according to Claim 4, wherein each connector comprises a generally tubular spigot passing through an aperture in the panel and communicating with the interior of a conduit, means being provided for holding the spigot to the panel.

6. A water heating boiler according to Claim 5, wherein the tubular spigot includes two portions of different cross dimensions providing a shoulder between them, the smaller portion passing through an aperture in the panel so that the shoulder abuts one side face of the panel, holding means being provided to engage the smaller portion of the connector and abut the opposite side face of the panel.

7. A water heating boiler according to Claim 6, wherein at least the smaller portion of the spigot is circular in cross section, the holding means comprising a circlip engaging within an annular groove formed around the periphery of the spigot adjacent said opposite side face of the panel.

8. A water heating boiler according to any of Claims 1 to 7, wherein substantially all the conduits are located on one side of the panel and substantially all the operative boiler components are located on the other side of the panel.

9. A water heating boiler according to any of Claims 1 to 8, wherein the boiler casing includes a removable portion to provide access to the interior of the casing, and to the boiler components, and wherein the side of the panel on which the components are located faces said removable portion.

10. A water heating boiler according to any of Claims 1 to 9, wherein the panel constitutes a structural element of the boiler casing and contributes to the structural strength thereof.

11. A water heating boiler substantially as hereinbefore described with reference to the accompanying drawings.