WO2011036503A2

WO2011036503A2 - Apparatus and method for preventing a condensate drain pipe from freezing

Info

Publication number: WO2011036503A2
Application number: PCT/GB2010/051970
Authority: WO
Inventors: Timothy Adam Fellows
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-09-25
Filing date: 2010-11-25
Publication date: 2011-03-31
Anticipated expiration: 2012-03-25
Also published as: GB2474918A; GB2474918B; WO2011036503A3; GB0916842D0; GB201005418D0

Abstract

An apparatus for preventing a condensate drain pipe (14) from freezing comprises a fitting (16) adapted to connect to the condensate drain pipe (14) and a fan (32) mounted to the fitting (16), in use, the fan (32) introducing a flow of warm air through the fitting for passing warm airflow through the condensate drain pipe (14).

Description

APPARATUS AND METHOD FOR PREVENTING A CONDENSATE DRAIN PIPE FROM FREEZING

The present invention relates to an apparatus and method for preventing a condensate drain pipe from freezing and particularly, but not exclusively, to an apparatus and method for preventing a condensate drain pipe of a domestic or commercial condensing boiler from freezing.

BACKGROUND TO THE INVENTION

Modern gas boilers are typically condensing boilers, which utilise the heat in the waste gases of combustion by condensing them, thereby achieving an improvement in efficiency of around 10%. The condensate is slightly acidic and is typically piped away from the boiler in a plastics pipe, into a drain. Usually the pipe extends through an external wall and into an external drain or soak away. Ideally the pipe should extend directly into the drain and preferably below ground. In the UK, it is recommended that the drain pipe extends 25mm below ground. The reason for this is to try and prevent freezing of the condensate in the drain pipe. Boiler condensate tends to freeze at a slightly higher temperature than, for example, water and therefore is prone to freezing in frosty conditions.

If the condensate freezes, it can block the condensate pipe causing the boiler to fail. In very cold conditions, even if the condensate pipe is insulated, the condensate may still freeze. In some cases this can cause damage to the boiler. Furthermore, in cold conditions when the condensate is likely to freeze, the need for the boiler to operate is even greater, because without a boiler, homes and offices can be left with no other heating and can quickly become cold. This can have serious consequences if homes are without heat for some time. Usually, in a cold period, the condensate pipes of large numbers of domestic boilers freeze at the same time and there is often a shortage of service engineers to service the boilers and attend to problems caused by the condensate freezing. For example, for engineers to receive around 10,000 reported faults per day is not unusual in a frosty cold period in the UK. It is an object of the invention to provide an apparatus and method for preventing a condensate drain pipe from freezing which reduces or substantially obviates the above mentioned problems. SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided an apparatus for preventing a condensate drain pipe from freezing comprising a fitting adapted to connect to the condensate drain pipe and a fan mounted to the fitting, in use, the fan introducing a flow of warm air through the fitting for passing warm airflow through the condensate drain pipe.

The term "warm air" is intended to be interpreted as meaning air having a temperature above the freezing point of boiler condensate. In most environments, the air can be ambient air taken from within a building where a boiler is situated. Alternatively, a heat source may be provided as required to warm the air supplied to the fan.

The apparatus of the invention is advantageous because it prevents ice from forming in the condensate drain of a boiler and prevents the knock on effects of an unintended boiler shut down in cold weather. Conveniently the apparatus can be fitted to any existing condensing boiler system, simply by interrupting the condensate drain pipe and inserting the apparatus, preferably in a vertically extending position before the pipe passes through an external wall to the drainage point. By providing airflow through the drain pipe and the condensate surface, ice seeding points are reduced through evaporation and movement on the fluid surface.

The fitting may have a body portion and a chamber extending through the body portion with inlet and outlet connectors provided on the body portion at first and second ends of the chamber. This enables the fitting to be connected into a condensate drain pipe. The connectors may be of any suitable type, for example, screw threaded or push fit to make a seal with the condensate pipe. A duct may pass from the fan and into the chamber and a guide member may be provided in the chamber for guiding airflow from the duct towards the outlet.

The guide member may guide condensate passing through the chamber away from the duct and towards the outlet.

The fan may be adapted to draw in ambient air. Alternatively, the fan may be directly connected to a heat source by a pipe or duct for conditions in which the ambient air is not suitably warm. The pipe or duct may be flexible for ease of installation.

The fan may be connected to a heat exchanger and the heat exchanger may be adapted to be attached to a hot water pipe.

Preferably, the heat exchanger includes a housing having an air inlet, an air outlet and a substantially part cylindrical aperture extending there-through for placement against a hot water pipe. Ideally the heat exchanger is adapted to be attached to a portion of 22mm diameter hot pipe from the boiler. This may be a hot or return heating flow pipe, or a hot water supply pipe. A plurality of fins may be provided within the housing for transferring heat from the region of the part cylindrical aperture. The part cylindrical aperture may be defined by a curved plate adapted to contact the pipe along its length, the fins being attached to the plate. The air inlet aperture may be provided in the side of the heat exchanger housing for allowing ambient air into the heat exchanger. The ambient air may pass over the fins, which are warmed by the hot pipe, through the connecting duct or piping and into the fitting. A thermostat may be provided on the condensate drain for identifying when the temperature is below the freezing point of the condensate. The thermostat may be hard wired or wirelessly connected to a controller for controlling operation of the fan.

In this way, the condensate drain will always be warmed by the airflow when there is a risk of freezing. According to a second aspect of the present invention there is provided a method of preventing a condensate drain pipe from freezing comprising introducing a flow of warm air through the drain pipe.

The method may utilise the apparatus in accordance with the first aspect of the invention.

According to a third aspect of the invention there is provided a heat exchanger comprising a housing having an air inlet, an air outlet and a substantially part cylindrical aperture extending there-through for placement against a hot water pipe. Ideally the heat exchanger is adapted to be attached to a portion of 22mm diameter hot pipe from the boiler, although the heat exchanger may be adapted to fit other sizes of pipe, as desired. This may be a hot or return heating flow pipe, or a hot water supply pipe.

A plurality of fins may be provided within the housing for transferring heat from the region of the part cylindrical aperture. The part cylindrical aperture may be defined by a curved plate adapted to contact the pipe along its length, the fins being attached to the plate for transferring heat.

The air inlet aperture may be provided in the side of the heat exchanger housing for allowing ambient air into the heat exchanger. The ambient air may pass over the fins, warmed by the hot pipe, and then pass into the fitting through the connecting duct or piping.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

Figure 1 shows a schematic side view of a boiler fitted to an outside wall of a building, a condensate drain pipe and an apparatus of the invention; Figure 2 shows a schematic underside perspective view of the boiler, drain pipe and apparatus of Figure 1;

Figure 3 shows a front view of the apparatus according to the invention;

Figure 4 shows a cross-sectional view through the apparatus of Figure 3;

Figure 5 shows a cross-sectional view through the apparatus of Figure 3 along line A- A;

Figure 6 shows a perspective view of a first embodiment of a heat exchanger for fitting to a pipe;

Figure 6A shows a cross-sectional view through the centre of the heat exchanger of Figure 6;

Figure 7 shows a perspective view of a second embodiment of heat exchanger for fitting to a pipe; and Figure 7A shows a cross-sectional view through the centre of the heat exchanger of Figure 7.

DESCRIPTION OF PREFERRED EMBODIMENT(S)

Referring firstly to Figures 1 and 2, a condensing boiler 10 is shown fitted to an external wall 12 of a building. A condensate drain pipe 14 is shown extending downwardly from the underside of the boiler, is connected to a fitting 16, extends through the wall 12 and then extends down into the ground, indicated at 18. In the UK, it is recommended that the condensate drain pipe 14 extends below ground at least 25 mm, and this is as shown in Figure 1. A hot pipe 20 is also shown extending from the underside of the boiler 10 and a heat exchanger device 22 is shown mounted to the hot pipe 20 and will be described further in detail below. Referring now to Figures 3 and 4, the fitting 16 includes a body portion 24 having an internal chamber 26 extending right through the body portion. An inlet 28 is provided at one end of the body portion and an outlet 30 is provided at the other end of the body portion in communication with the internal chamber 26. Connectors 30, 31 are provided on the inlet and outlet respectively and are shown as screw threaded connectors. Seals, not shown, may also be provided to seal the condensate drain pipe 14 to the fitting 16 in conventional manner. It will appreciated that the condensate drain pipe is typically made from 22 mm outside diameter plastics, and the fitting 16 can be retro-fitted at any time or on initial installation of the heating system. A fan 32 is mounted externally to the body portion 24 on a pair of mounts 34. Air is drawn into the fan through a central aperture 36. A duct 38 connects the fan to the internal chamber 26 of the body portion 24 for supplying air into the internal chamber and into the condensate drain pipe 14. A guide member 40, which is curved and extends partially across the internal chamber 26, guides incoming air towards the outlet 30. The guide member 40 also guides condensate passing through the inlet 28 away from the exit of the duct 38 into the internal chamber 26. The shape of the guide member 40 causes a negative pressure on the inlet side of the internal chamber and tends to draw the condensate down through the body portion 24 towards the outlet and the drain side of the condensate drain pipe 14. The connection of the duct 38 to the internal chamber 26 and the position of the curved guide member 40 can also be seen in Figure 5. In use the fitting should be positioned vertically as viewed in Figure 4.

The fan 32 is arranged to draw ambient air from the room where the boiler 10 is situated, but in the event that the room temperature is below the freezing point of condensate, i.e. around 0 degrees centigrade, then the fan may draw air from the heat exchanger 22. Although not shown in Figure 2, a cowling may be provided on the outside of the fitting 16 which may connect with ducting or flexible piping which can also be connected to the heat exchanger 22.

Referring in particular to Figures 6 and 6A, a first embodiment of heat exchanger is indicated at 42. The heat exchanger 42 includes an external housing 44 having an inlet 46 in the form of a grill at one end thereof and an outlet 48 in the form of a tubular spigot at the other end thereof. A substantially part tubular wall 50 is provided along one side of the heat exchanger 42 and is adapted to be placed adjacent a hot water pipe. The other side of the housing is curved. Heat transfer fins 52 are provided along and connected to the part circular wall 50 and extend across the width of the housing 44. The heat transfer fins 52 are apertured to allow the free flow of air from the inlet 46 across the surface of the fins to the outlet 48.

A second embodiment of heat exchanger is indicated in Figures 7 and 7 A at 54, and is substantially identical in construction, save that the external shape of the housing is provided with a cross section in the shape of a quadrant of a circle. It will be appreciated that the shape of the heat exchanger can be selected according to the pipe work that the heat exchanger is to be fitted to, the location of the pipe work and the proximity of other pipes. In some circumstances it is envisaged that the second embodiment of heat exchanger 54 may not be able to physically fit onto the pipe work and therefore the embodiment 42 may be preferable.

Referring back to Figure 2, a control panel (not shown) is mounted to the fan 32. The control panel is powered by an electrical supply, preferably a 12 volt DC electrical supply for powering the fan 32. A thermostat 56, shown in Figure 1, is mounted proximate the condensate drain pipe 14, ideally at its lower end near the outlet. The thermostat 56 may be connected to the controller of the fitting 16 by hard wiring or by a wireless connection, for example, a radio frequency transmitter. In use, when the ambient temperature drops below freezing, then the controller will start the fan 32 and air will be drawn either from the room or a heat exchanger 42, 54 into the fitting 16 and into the condensate drain pipe 14, thus preventing freezing of condensate within the pipe. The fan 32 may operate intermittently or continuously. It may be dependent on ambient external temperature. In an alternative arrangement it is envisaged that a heating element may be provided in the fitting 16, although this is not a preferred option, because the heating element will generally require a separate power supply.

It will be appreciated that by the fitting of the apparatus of the invention, freezing of condensate from domestic and commercial boilers can be prevented during periods of cold weather, thereby preventing discomfort and distress to many people at home and in work. It is understood that variations may be made in the foregoing without departing from the scope of the invention. For example, the elements and teachings of the various illustrative embodiments may be combined in whole or in part in some or all of the illustrative embodiments. In addition, one or more of the elements and teachings of the various illustrative embodiments may be omitted, at least in part, and/or combined, at least in part, with one or more of the other elements and teachings of the various illustrative embodiments.

Although illustrative embodiments of the invention have been shown and described, a wide range of modification, changes and substitution is contemplated in the foregoing disclosure. In some instances, some features of the invention may be employed without a corresponding use of the other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.

Claims

1. Apparatus for preventing a condensate drain pipe from freezing comprising a fitting adapted to connect to the condensate drain pipe and a fan mounted to the fitting, in use, the fan introducing a flow of warm air through the fitting for passing warm airflow through the condensate drain pipe.

Apparatus as claimed in claim 1, in which the fitting has a body portion and a chamber extending through the body portion.

Apparatus as claimed in claim 1 or claim 2, in which inlet and outlet connectors are provided on the body portion at first and second ends of the chamber.

Apparatus as claimed in claim 2 or 3, in which a duct passes from the fan and into the chamber.

Apparatus as claimed in any one of claims 2 to 4, in which a guide member is provided in the chamber for guiding airflow from the duct towards the outlet.

Apparatus as claimed in claim 5, in which the guide member guides condensate passing through the chamber away from the duct and towards the outlet.

Apparatus as claimed in any preceding claim, in which the fan is adapted to draw in ambient air.

Apparatus as claimed in any preceding claim, in which the fan is directly connected to a heat source.

Apparatus as claimed in claim 8, in which the fan is connected to a heat exchanger.

Apparatus as claimed in claim 9, in which the heat exchanger is adapted to be attached to a hot water pipe.

11. Apparatus as claimed in claim 10, in which the heat exchanger includes a housing having an air inlet, an air outlet and a substantially part cylindrical aperture extending there-through for placement against a hot water pipe.

12. Apparatus as claimed in claim 11, in which a plurality of fins are provided within the housing for transferring heat from the region of the part cylindrical aperture.

13. Apparatus as claimed in claim 12, in which the part cylindrical aperture is defined by a curved plate adapted to contact the pipe along its length, the fins being attached to the plate for transferring heat.

14. Apparatus as claimed in any one of claims 11 to 13, in which the air inlet aperture is provided in the side of the heat exchanger housing.

15. Apparatus as claimed in any preceding claim, in which a thermostat is provided on the condensate drain for identifying when the temperature is below freezing point of the condensate.

16. Apparatus as claimed in claim 15, in which the thermostat is wirelessly connected to a controller for controlling operation of the fan.

17. A method of preventing a condensate drain pipe from freezing comprising introducing a flow of warm air through the drain pipe.

18. A method as claimed in claim 15, in which the apparatus as claimed in any one of claims 1 to 14 is fitted to the condensate pipe.

19. An apparatus for preventing a condensate drain pipe from freezing substantially as claimed herein with reference to and as illustrated in Figures 1 to 7A of the accompanying drawings.

20. A method for preventing a condensate drain pipe from freezing substantially as claimed herein with reference to and as illustrated in Figures 1 to 7 A of the accompanying drawings.