GB2281611A

GB2281611A - Building flue systems

Info

Publication number: GB2281611A
Application number: GB9416810A
Authority: GB
Inventors: John Sidney Shute
Original assignee: DUNBRIK (YORKS) Ltd
Current assignee: DUNBRIK (YORKS) Ltd
Priority date: 1993-09-07
Filing date: 1994-08-19
Publication date: 1995-03-08
Anticipated expiration: 2014-08-19
Also published as: GB9416810D0; GB2281611B; GB2281611A8

Abstract

A building flue having a section 40 (preferably of prefabricated pipe) which passes through the building roof space has an extractor fan 44 fitted (preferably retro fitted) thereto for enhanced removal of the exhaust gases created by a gas fire in the hearth 16 served by the flue. A first section 20 of the flue is constructed of flue blocks and a second section leading to a ridge vent terminal 24 is a prefabricated metal pipe section and consists of a number of pipe elements 26, 28, 30, 32, 34, 36. The fan 44 is electrically operated which is control coupled to a gas fire of hearth 16. <IMAGE>

Description

2281611 Improvements Relating to Flue Systems This invention relates to f

lue systems,, and in particular relates to those flue systems which are built into buildings, typically domestic dwellings, for the removal of exhaust gases comprising products of combustion.

When a domestic dwelling is provided with a gas f ire as a heating source, especially those gas fires which are designed to simulate burning coal or burning wood, it is important that the flue should function efficiently and provide effective discharge of the exhaust gases from the building. There are specifications for the efficient extraction of the exhaust gases by the f lue, and if the flue does not meet these specifications, then Gas Board inspectors have the right to condemn the flue as failing to perform its function, and builders and/or gas fire installers then have to rectify the situation in order that the system will meet the specifications.

When one takes into account that flue systems frequently include a section which is made up of flue blocks, the process of rectifying a condemnation by the Inspector can be time consuming and expensive and the worst cases may require dismantling of the flue.

As mentioned above, many flue systems in domestic dwellings are made up partially of a flue block built section, connected to a section comprising pre-fabricated pipe means, the pipe means typically extending through the roof void in the building to a flue outlet vent terminal on the roof, for example on the roof ridge.

Some other flues on the other hand comprise a block or brick built construction from the hearth to a chimney stack, but 2 again it is not unusual for a section of such f lue to pass through the building roof void.

In efforts to improve flue functioning. it has been proposed to provide extractor f an units which are mounted atop the flue stack to the outside of the building. As can be appreciated, these extractor f an units are robust and heavy units designed to cope with varying weather conditions as they will be exposed to the elements.

The present invention seeks to overcome the disadvantages of inefficient flues, and provides for exhaust gas extraction from flues in a simple and convenient manner.

In accordance with the present invention, in a flue, an extractor fan means is provided, said fan means being connected in the flue where it passes through the roof space of the building.

Preferably, the extractor fan means is used with a flue comprising at least a section of prefabricated pipe which extends through the roof space, so that the fan can either be retrofitted into an existing flue system, or can be built into the prefabricated pipe means.

The prefabricated pipe means preferably is made up in sections which are interfitted, so that in retrofitting of the fan means, a section can be removed and replaced by another section containing the fan means.

The fan means preferably is an electrically operated fan, control coupled to a gas fire of the flue hearth, so that it is operational when the hearth fire is operational, and switches off when the fire is not operational.

3 The extractor fan may be of quite light delivery, i.e. of the order of 6 to 10 cu.ft per minute, and initial tests have shown that the invention works particularly efficiently.

Poor functioning of flues can arise for a number of reasons including that where a flue block section is included, the flue blocks have not been sufficiently accurately arranged in the construction of the flue, or if the building is located in a region where because of surrounding buildings, the air around the house is relatively still so that there is very little natural induction. The use of the invention can solve these difficulties.

The fan itself may be a relatively inexpensive and simple unit comprising an impeller of metal or heat resistant plastic material supported by bearings in a metal or heat resistant plastic support cage extending from a sleeve which fits into the pipe section to be fitted into the pipe section of the flue.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, wherein:- Fig. 1 is a perspective view of a flue system of a two storey domestic dwelling; and Fig. 2 is a sectional elevation of the portion of the pipe section of the flue containing an extraction fan.

Referring to Fig. 1, in this figure is illustrated a domestic flue system for a two storey dwelling. The f irst f loor division is illustrated by joist structure 10, whilst 12 indicates the insulation of the ceiling of the second floor.

4 Ground f loor level is indicated by 14, and 16 indicates a hearth which is designed to receive an open gas f ire. The hearth has a support cover block 18, and the first section of the flue 20 is constructed of flue blocks arranged as illustrated.

The interior walls are plaster board dry lined as indicated by reference 22.

The second section of the flue system leading to a ridge vent terminal 24 is a prefabricated metal pipe section made up of a number of pipe elements as follows:- 26 - a side exit element 28 - an adjustable elbow - a 5 ft length 32 - a 3 ft length 34 - an 18 inch adjustable length 36 - an adjustable elbow The pipe section is supported by one or more arm support units 38 which is/are connected to the roof truss, the pipe section of the flue lying in the roof space.

In accordance with the invention a section 40 of the pipe portion of the f lue contains the unit shown in Fig. 2 which includes an extractor fan 44.

The section 40 comprises inner and outer metallic walls 46, 48, the other sections of the pipe portion of the flue also being constructed of parallel walls for insulation purposes.

Inside the inner portion 48 is a fan casing sleeve 50 which supports the frames 52 and 54, carrying a drive motor 56 whose shaft 58 supports the fan impeller 60.

62 indicates the electrical connection to the motor 56, and when the motor 56 is operational, air is drawn through the section 40 as indicated by arrows 64 and 66. This small unit effectively clears the flue system of exhaust gases in an efficient manner.

The various elements of the pipe section of the flue are fitted together by a quick release coupling arrangement, and the section 40 will be designed to be fitted in the same way.

The section 40 can be arranged at any location throughout the length of the pipe section of the f lue, as long as it is located in the roof space where it can be easily accessed for removal and repair from inside the roof space. The unit is particularly suitable for retro-fitting to existing flue systems, or it can be embodied in a newly constructed f lue system as required.

Furthermore, a fan unit can be fitted into a flue system in a roof space even when the roof system does not embody pipe section as illustrated in Fig. 1.

A simple and effective means is provided for overcoming the very serious problems which exist in providing flues which meet regulation standards.

6

Claims

1. In a building flue which passes through the roof space of W a building, an extractor f an connected in the f lue where it passes through said roof space.

2. An extractor f an as claimed in Claim 1, wherein the flue comprises a section of fabricated pipe which extends through said roof space said extractor fan being in said pipe.

3. An extractor f an according to Claim 2, wherein said pipe is made up in interfitting sections one of which contains the fan.

4. An extractor f an according to any preceding claim, which is electrically operated and is control coupled to a gas fire in the hearth served by the flue, so that the fan is operational when the hearth fire is operational.

5. An extractor f an according to any of claims 1 to 4, of delivery in the range 6 to 10 cu. ft. per minute.

6. An extractor fan according to any preceding claim, wherein the f an comprises an impeller of metal or heat resistant plastics supported in bearings in a metal or heat resistant plastic support cage extending from a sleeve which fits into said pipe section.

7. In or f or a building f lue which passes through the roof space f a building, an extractor fan substantially as hereinbefore described with reference to the accompanying drawings.