GB2564907A

GB2564907A - Improvements relating to domestic radiators

Info

Publication number: GB2564907A
Application number: GB1712116.1A
Authority: GB
Inventors: Beverly Lucas Nigel
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-07-27
Filing date: 2017-07-27
Publication date: 2019-01-30
Also published as: GB201712116D0

Abstract

A central heating system radiator 100 comprises internal pipework 101 to receive a heat transfer fluid. The radiator includes inlet 110 and outlet 120 pipe openings, ideally in a lower region of the radiator in use, that are in fluid communication with the internal pipework and are connectable to the heating system. A drain opening 130 is located in the lower region of the radiator and is connectable to a drain valve 180. The drain opening is also in fluid communication with the internal pipework and permits discharge of heat transfer fluid out of the radiator. The drain valve may be located in or on the drain opening. When a drain valve is fitted the radiator can be purged of heat transfer fluid by attaching a hose to a drain spout 182 of the valve, opening an air bleed valve 140, and turning a control nut 183 to open the drain valve. A blanking cap (200, figure 5) may be used to seal the drain opening when the drain valve is not fitted.

Description

The present invention relates to a heat exchanger, in particular to domestic radiators for use in central heating systems.

Background

Heat exchangers may be used in many different situations to transfer thermal energy from a first fluid to a second fluid in order to heat the second fluid and/or to cool the first fluid. For example, the first fluid may be a heat transfer fluid, such as an aqueous liquid, which has been heated by a boiler and pumped to the heat exchanger. The second fluid may be the ambient air surrounding the heat exchanger, for example in a room to be heated. The heat exchanger may then function by providing a means for the thermal energy from the heat transfer fluid to pass to the ambient air surrounding the heat exchanger by convection. Such heat exchangers may be known as radiators.

Radiators may be used in domestic central heating systems to allow thermal energy in a heat transfer fluid flowing through the system and the radiators to warm the air surrounding the radiators, and thereby heat the rooms in which the radiators are situated. A domestic central heating system typically comprises a boiler, a pump, a plurality of radiators and pipework connecting the radiators. The boiler is arranged to heat a heat transfer fluid which is then pumped under pressure through the pipework to the radiators by the pump.

Domestic central heating systems comprise sealed systems and open-vented systems. Sealed systems are operated under pressure and comprise a pressurisation unit and an expansion vessel. Open-vented systems are open to the atmosphere and comprise a feed/expansion tank.

Typically, radiators used in domestic central heating systems comprise internal pipework adapted for receiving heat transfer fluid; an inlet pipe opening and an outlet pipe opening in fluid communication with the internal pipework for connection of the heat exchanger to a central heating system, the inlet and outlet pipe openings typically located in a lower part of the radiator; and a bleed valve located in an upper part of the heat exchanger.

Summary of the Invention

During the maintenance or replacement of a heat exchanger, such as a domestic radiator, it may be necessary to remove a heat transfer fluid from the heat exchanger. A conventional method of removing a heat transfer fluid from a heat exchanger is to use a draining port arranged in pipework of a central heating system to which the heat exchanger is attached, the draining port typically arranged in a lower part of said pipework, typically near a boiler. Such a draining port can be opened to drain heat transfer fluid from the heat exchanger. This also drains heat transfer fluid from other parts of the central heating system, for example from other heat exchangers arranged in the central heating system, possibly draining heat transfer fluid from the entire central heating system. Therefore, this method affects parts of the central heating system other than the heat exchanger which needs to be drained, making the operation more arduous than if a single heat exchanger could be drained.

An alternative method of removing a heat transfer fluid from a heat exchanger which is part of a central heating system is to isolate the heat exchanger from the central heating system, detach at least an outlet pipe or an inlet pipe from the heat exchanger and allow the heat transfer fluid to drain out through an outlet or inlet opening. Alternatively, the heat exchanger may be completely removed from the central heating system and then manipulated to pour the heat transfer fluid out of the heat exchanger. These operations can be cumbersome and often lead to spillage of heat transfer fluid due to the uncontrolled manner in which the heat transfer fluid may flow out of the heat exchanger. This problem may be particularly acute where the heat exchanger is fitted in a location having flooring, for example carpet, which may be stained or otherwise damaged by spilt heat transfer fluid.

Therefore there is a need for improved methods of removing heat transfer fluid from heat exchangers, such as domestic radiators.

It is one aim of the present invention, amongst others, to provide a heat exchanger and/or method that addresses at least one disadvantage of the prior art, whether identified here or elsewhere, or to provide an alternative to existing heat exchangers and methods. For instance, it may be an aim of the present invention to provide a heat exchanger and/or method which enables a user to remove heat transfer fluid from a heat exchanger with improved convenience in relation to the prior art.

According to aspects of the present invention, there is provided a heat exchanger, and related methods and uses, as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

According to the first aspect of the present invention, there is provided a heat exchanger for use in a central heating system, the heat exchanger comprising:

internal pipework adapted for receiving a heat transfer fluid in use;

an inlet pipe opening in fluid communication with the internal pipework and adapted for connection to said central heating system in use;

an outlet pipe opening in fluid communication with the internal pipework and adapted for connection to said central heating system in use;

a drain opening in fluid communication with the internal pipework, wherein the drain opening is located in a lower region of the heat exchanger in use, and wherein the drain opening is adapted to receive a drain valve.

The drain opening suitably allows said heat transfer fluid, when present in the heat exchanger in use, to drain out of the heat exchanger.

By “heat exchanger”, we mean a device for transferring thermal energy from a first fluid to a second fluid, without the first and second fluids coming into direct contact with one another. The heat exchanger of this first aspect may be any of a wide range of heat exchangers. Suitably, the heat exchanger of this first aspect is a radiator, for example a domestic radiator.

By “heat transfer fluid”, we mean a gas or a liquid which flows through a heat exchanger for transferring thermal energy to or from a second fluid, for example ambient air. The heat exchanger of this first aspect may be used with a wide range of heat transfer fluids, suitably heat transfer liquids, for example an aqueous heat transfer liquid. The aqueous heat transfer liquid may comprise additives, for example anti-corrosion additives. For the avoidance of doubt, the heat transfer fluid is not intended to be air.

The internal pipework is suitably the pipework forming the channel inside the heat exchanger through which heat transfer fluid flows in use. The term may be taken as encompassing all of the pipework between the inlet opening and the outlet opening. Therefore the drain opening is suitably located along the channel inside the heat exchanger formed by the internal pipework, at a point between the inlet opening and the outlet opening.

The drain opening is suitably an aperture in an outer wall of the heat exchanger passing from the inside of the internal pipework of the heat exchanger to the outside of the heat exchanger. Suitably the outer wall through which the drain opening passes is a part of a wall of the internal pipework of the heat exchanger.

The drain opening being in fluid communication with the internal pipework and located in a lower region of the heat exchanger allows heat transfer fluid, when present in the heat exchanger in use, to flow under gravity out of the heat exchanger through the drain opening. It will be appreciated that in order to use the heat exchanger, for example as part of a domestic central heating system, the drain opening would need to be closed during normal operation, for example by using a closable drain valve or a blanking cap.

Suitably the drain opening has a diameter of at least 5 mm, suitably at least 7 mm. The drain opening suitably has a diameter of up to 20 mm, suitably up to 15 mm, suitably up to 10 mm. Suitably the drain opening has a diameter of from 5 to 20 mm, suitably from 5 to 15 mm.

References to “lower” and “upper” regions and parts of the heat exchanger are with respect to the normal, intended orientation of the heat exchanger in use. Domestic radiators are typically arranged so that the inlet and outlet openings are at a bottom or lower region of the radiator and any bleed valve present is at a top or upper region of the radiator. The skilled person would understand these terms in the context of the present invention.

Suitably the heat exchanger of this first aspect comprises a bleed valve located in an upper region of the heat exchanger in use.

Bleed valves are suitably fitted to heat exchangers, in particular to domestic radiators. Such bleed valves, when opened, provide an outlet in an upper part of the heat exchanger for fluids, such as air or heat transfer fluid. Opening such a bleed valve may therefore allow air in the heat exchanger to be removed and replaced with heat transfer fluid when a heat transfer fluid enters the heat exchanger under pressure. Also, opening such a bleed valve may allow air to enter the heat exchanger to replace heat transfer fluid which is draining from the heat exchanger through the drain opening.

Suitably the drain opening faces downwards away from the heat exchanger in use. Suitably the drain opening faces substantially vertically downwards from the heat exchanger in use. Suitably the drain opening faces vertically downwards from the heat exchanger in use.

Suitably the drain opening is located in a lowest point on the heat exchanger in use. Suitably the drain opening provides fluid communication between the lowest point in the internal pipework of the heat exchanger, in use, and the outside of the heat exchanger. When located in the lowest point on the heat exchanger in use, the drain opening may function to drain substantially all of a heat transfer fluid present in the heat exchanger, under gravity, providing an efficient emptying process.

Suitably the heat exchanger comprises a threaded connector within or surrounding the drain opening, the threaded connector adapted for engaging with a drain valve.

Such a threaded connector may facilitate the connection of a drain valve to the drain opening in order to allow the drain opening to perform its advantageous function.

Suitably the inlet pipe opening and the outlet pipe opening are arranged in the lower region of the heat exchanger in use.

Suitably the drain opening is located adjacent to the inlet pipe opening or the outlet pipe opening. The internal pipework of typical heat exchangers, such as domestic radiators, is wider and more accessible near to the inlet and/or outlet pipe than at other parts of the internal pipework and therefore provides a favourable location for the drain opening and subsequent attachment of a drain valve.

Suitably the heat exchanger comprises a removable blanking cap located in the drain opening, wherein the removable blanking cap closes and seals the drain opening to prevent the passage of said heat transfer fluid out of the heat exchanger through the drain opening, in use.

Suitably the blanking cap comprises a plug, for example a rubber plug, for closing and sealing the drain opening in use.

Suitably the blanking cap comprises a plug attached to the blanking cap with a retainer.

The retainer may advantageously retain the plug on the blanking cap when the blanking cap is removed from the drain opening, in use. If a blanking cap of the prior art, which is used with rubber plug fitted onto a stem, is left for a long period of time in an opening, such as the drain opening, then removing the blanking cap may leave behind the plug in the opening. The plug may then be very difficult to remove from the opening. The retainer fitted to the blanking cap of the present invention may ensure that when the blanking cap is removed from the drain opening, the plug is also removed and the drain opening unblocked. A drain valve may then be arranged in the drain opening.

Suitably the heat exchanger comprises a drain valve located in the drain opening, the drain valve adapted to selectively allow or prevent the passage of said heat transfer fluid out of the heat exchanger through the drain opening, in use.

Suitably the drain valve comprises an attachment fitting suitable for engaging with the drain opening, for example a threaded attachment fitting suitable for engagement with a threaded connector within or surrounding the drain opening.

Suitably the drain valve comprises a connector adapted for engagement with a hose.

Suitably the drain valve comprises a drain spout for allowing said heat transfer fluid to flow out of and away from the heat exchanger. Suitably the drain spout comprises a connection fitting for use with a hose.

In some embodiments, the heat exchanger of this first aspect is provided as a kit comprising the heat exchanger and a drain valve as described above. Suitably the kit comprises the heat exchanger, the drain valve and a blanking cap as described above. Providing the heat exchanger as part of this kit gives the user the option of arranging the blanking cap in the drain opening to seal the drain opening in use, or arranging the drain valve in the drain opening to selectively allow or prevent the passage of a heat transfer fluid out of the heat exchanger through the drain opening, in use, depending on the requirements of the user.

According to a second aspect of the present invention, there is provided a method of manufacturing a heat exchanger according to the first aspect, the method comprising the steps of:

a) providing a heat exchanger comprising:

internal pipework adapted for receiving a heat transfer fluid in use;

an inlet pipe opening in fluid communication with the internal pipework and adapted for connection to said central heating system in use; and an outlet pipe opening in fluid communication with the internal pipework and adapted for connection to said central heating system in use; and

b) providing a drain opening in fluid communication with the internal pipework, wherein the drain opening is located in a lower region of the heat exchanger in use, and wherein the drain opening is adapted to receive a drain valve.

Suitably step b) involves drilling into the heat exchanger to provide the drain opening.

Suitably step b) involves inserting a threaded connector into the drain opening.

Suitably step b) involves attaching a threaded connector onto the heat exchanger and around the drain opening.

According to a third aspect of the present invention, there is provided a method of removing a heat transfer fluid from a heat exchanger, the heat exchanger comprising a bleed valve and a drain valve, the drain valve located in a lower region of the heat exchanger in use, the method comprising the steps of:

a) opening the bleed valve to allow air to enter the heat exchanger through the bleed valve; and

b) with the bleed valve open, opening the drain valve to allow the heat transfer fluid to pass out of the heat exchanger through the drain valve.

Suitably the drain valve is adapted to selectively allow or prevent the passage of said heat transfer fluid out of the heat exchanger through the drain valve.

The method of this third aspect may be carried out on a heat exchanger according to the first aspect.

Brief Description of the Drawings

For a better understanding of the invention, and to show how example embodiments may be carried into effect, reference will now be made to the accompanying drawings in which:

Figure 1 is a perspective view of a heat exchanger according to the first aspect of the present invention, viewed from underneath.

Figure 2 is a perspective view of a drain valve for use with the heat exchanger of Figure 1.

Figure 3 is an orthogonal view of the side of the heat exchanger of Figure 1.

Figure 4 is a perspective view of part of a heat exchanger according to the first aspect of the present invention comprising a drain valve, viewed from underneath.

Figure 5 is perspective view of a blanking cap for use with the heat exchanger of Figure 1.

Detailed Description of the Example Embodiments

Figure 1 shows a heat exchanger (100) which is a domestic radiator, viewed from underneath. The heat exchanger (100) comprises an inlet pipe opening (110), an outlet pipe opening (120) and a drain opening (130). The heat exchanger also comprises a bleed valve (140 - not shown). The heat exchanger (100) comprises panel (150) and fins (160). The heat exchanger (100) comprises internal pipework (101), a major part of which is containing within panel (150). The internal pipework (101) receives, in use, a heat transfer fluid and allows thermal energy of the heat transfer fluid to be transferred by conduction to the air surrounding the heat exchanger (100), with the aid of the fins (160), thereby heating the room in which the heat exchanger is situated by convection.

The inlet pipe opening (110), the outlet pipe opening (120), the drain opening (130) and the bleed valve (140) are all in fluid communication with the internal pipework of the heat exchanger (100). The inlet pipe opening (110) and the outlet pipe opening (120) are identical and allow the heat exchanger (100) to be connected to a domestic central heating system (not shown). The inlet pipe opening (110) and the outlet pipe opening (120) provide two ends (termini) of the internal pipework of the heat exchanger (100). During operation of the domestic central heating system, a heat transfer fluid is pumped from a boiler (where it is heated) to the heat exchanger (100) through inlet opening (110) and out of the heat exchanger (100) through outlet opening (120). Whilst in the heat exchanger (100), thermal energy of the heat transfer fluid is transferred by conduction to the air surrounding the heat exchanger (1000), thereby heating the room in which the heat exchanger is situated by convection.

The inlet pipe opening (110), the outlet pipe opening (120) and the drain opening (130) are located in a lower region of the heat exchanger (100). In normal use of the heat exchanger (100), the lower region would be the region nearest the floor of the room in which the heat exchanger (100) is situated. Suitably the inlet pipe opening (110), the outlet pipe opening (120) and the drain opening (130) are located in pipework arranged at the bottom of the heat exchanger so that in use the majority of the internal pipework of the heat exchanger (100) is above the inlet pipe opening (110), the outlet pipe opening (120) and the drain opening (130).

The drain opening (130) is located in the internal pipework of the heat exchanger (100) adjacent to and inward of the inlet opening (110) and outward of the panel (150) along the internal pipework of the heat exchanger (100). The drain opening (130) is a drilled hole with an 11.9 mm diameter.

Alternatively, the drain opening (130) may be located in the bulge region (170) of the internal pipework of the heat exchanger (100) which is also inward of the inlet opening (110) and outward of the panel (150) along the internal pipework of the heat exchanger (100). Both the location of the drain opening (130) shown and the bulge region (170) are where the internal pipework of the heat exchanger (100) is relatively wide compared to the internal pipework in the panel (150), making these positions for the drain opening (130) particularly suitable.

The drain opening (130) is orientated to face outwards from the bottom of the heat exchanger (100), in use, to allow heat transfer fluid to flow out of the internal pipework of the heat exchanger (100) under gravity.

The drain opening (130) is surrounded by a collar (131) comprising an internal thread (132) for engagement with a drain valve. The collar (131) has a diameter of 20 mm, a depth of 9 mm and the internal thread (132) is a 1/4 BSP thread suitable for receiving a drain valve having a 1/4 inch BSPT sized fitting thread.

Figure 2 shows a drain valve (180) suitable for use with the heat exchanger (100) of Figure 1. Drain valve (180) comprises a fitting thread (181), a drain spout (182) and a valve control nut (183). The fitting thread (181) is suitable for engagement with the internal thread (132) on of drain opening (130) to from a seal with drain opening (130). The fitting thread (181) is attached to a main body (184) of the drain valve (180) with an octagonal portion (185) to facilitate fitting of the drain valve (180), using a spanner for example. The fitting thread may have a suitable diameter and thread size for engaging with the thread (132) of the drain opening (130). For example, the fitting thread may be a 1/4 inch BSPT sized fitting thread for engaging with the internal thread (132) of the collar (131) of drain opening (130).

Drain spout (182) may be adapted to facilitate attachment of a hose for receiving said heat transfer fluid and directing said heat transfer fluid into a suitable vessel. For example, the drain spout (182) has been drilled and tapped to allow connection fitting (190) to be screwed into the drain spout. Connection fitting (190) comprises a male connecting portion (191) for engaging with a complimentary female connection fitting on a suitable hose.

In some embodiments, the drain spout may be provided with ribs around the circumference of the drain spout to engage with a hose of a common diameter.

Figure 3 shows the heat exchanger (100) of Figure 1 fitted with a drain valve (180) of Figure 2. The heat exchanger (100) is connected to a central heating system via connection of inlet pipe opening (110) to inlet pipe (111) through inlet valve (112) and via connection of outlet pipe opening (120) to outlet pipe (121) through outlet valve (122).

The drain spout (182) has a suitable diameter, length and downward orientation, in use, to facilitate the flow of heat transfer fluid out of and away from the heat exchanger (100), through the drain valve (180),

The drain valve control nut (183) selectively allows or prevents the flow of fluid out of the drain spout (182) by rotation of the drain valve control nut (183) between an on and off position, for example using a suitable tool or key.

Figure 4 shows a close-up view of the drain valve (180) of Figure 2 arranged in a drain opening (430 - not visible) of a heat exchanger (400), the drain opening comprising collar (431) and internal thread (432),. The heat exchanger (400) only differs from the heat exchanger (100) of Figures 1 and 3 in that the drain opening (430) is located in the bulge region (470) rather than adjacent to and inward of the inlet opening (410).

Figure 5 shows blanking cap (200) for use with heat exchanger (100) to close and seal the drain opening (130) when a user chooses not to fit a drain valve (180). Blanking cap (200) comprises head (201), thread (202), plug (203), washer (204) and retaining bolt (205). The blanking cap is arranged so that when screwed into drain opening (130) using thread (202), plug (203) is pressed against and seals the drain opening (130). The rubber plug (203) is suitably made of rubber and is retained on blanking cap (200) by retaining bolt (205) and washer (204), the retaining bolt (205) being screwed into a suitable hole in the head (201) to urge washer (204) into contact with plug (203) to prevent the plug (203) from separating away from the blanking cap (200) in use. As discussed above, such plugs on prior art blanking caps may become separated from the blanking cap and block the drain opening, preventing the insertion of a drain valve (180), and may be very difficult to remove, particularly if the blanking cap has been left in place for a long time.

The heat exchanger (100) or (400) may be manufactured by first providing a standard known heat exchanger comprising internal pipework, an inlet pipe opening and an outlet pipe opening; and then providing a drain opening (130) in a lower region of the heat exchanger, wherein the drain opening is adapted to receive a drain valve. The drain opening (130) may be provided by drilling into the internal pipework of the heat exchanger at the suitable locations discussed above. The drain opening (130) may be adapted to receive a drain valve by providing a threaded collar, such as threaded collar (131) around or inside the drain opening (130), for example by welding. Therefore, the heat exchanger (100) may be manufactured by modifying a standard known heat exchanger. Alternatively, the drain opening (130) may be incorporated into the manufacture of the heat exchanger at an earlier stage, for example by forming the internal pipework of the heat exchanger with the drain opening (130) pre-made, for example in a casting process.

In order to empty the heat exchanger (100) of heat transfer fluid (not shown), in a method according to the third aspect of the present invention, the following procedure may be carried out. With the inlet valve (112) and the outlet valve (122) closed, bleed valve (140) is opened, suitably with the domestic central heating system to which the heat exchanger is connected switched off. A suitable vessel may be positioned underneath the drain valve (180) or a hose may be connected to the drain spout (182), as discussed above. The hose may be connected to a suitable vessel. The drain valve (180) is then opened by actuating the drain valve control nut (183). The heat transfer fluid will then flow out of the heat exchanger (100) and may be collected in the vessel for later re-use or disposal.

If the emptying of the heat exchanger (100) is part of a procedure of replacing the heat exchanger (100), once the heat exchanger (100) is empty, it may be disconnected from the inlet pipe opening (110) and the outlet pipe opening (120), and removed from the central heating system. A replacement heat exchanger (analogous to heat exchanger 100), which is empty of heat transfer fluid and therefore filled with air, may then be connected to the inlet pipe opening (110) and the outlet pipe opening (120) using standard plumbing techniques.

Draining a heat exchanger with this method using a drain valve fitted to a drain opening (130) of the heat exchanger, as described above, may avoid spillages which may occur when draining heat exchangers of the prior art which do not comprise such drain openings (130). This method may also conveniently retain the removed heat transfer fluid for later use, for example to fill a replacement heat exchanger.

Furthermore, by isolating and draining a single heat exchanger (100) in a central heating system comprising a plurality of such heat exchangers, temporary removal, replacement or maintenance of said heat exchanger can be carried out without unbalancing the central heating system, without reducing the amount of heat transfer fluid in the system and without incorporating air pockets into the system; any of which may adversely affect the performance ofthe domestic central heating system and necessitate further work to rectify.

Therefore the heat exchanger and methods of the present invention may improve the efficiency ofthe plumbing operations discussed above.

In summary, the present invention provides a heat exchanger for use in a central heating system. The heat exchanger comprises internal pipework adapted for receiving a heat transfer fluid in use and inlet and outlet pipe openings in fluid communication with the internal pipework and adapted for connection to said central heating system. The heat exchanger also comprises a drain opening in fluid communication with the internal pipework, the drain opening adapted to allow said heat transfer fluid, when present in the heat exchanger in use, to drain out of the heat exchanger, for example through a drain valve located in or over the drain opening. The invention relates in particular to domestic radiators for use in central heating systems and may facilitate the removal of a heat transfer fluid from a heat exchanger. A method of removing heat transfer fluid from a heat exchanger is also provided.

Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope ofthe invention, as defined in the appended claims.

Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of other components. The term “consisting essentially of’ or “consists essentially of” means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effect ofthe invention.

The term “consisting of” or “consists of’ means including the components specified but excluding addition of other components.

Whenever appropriate, depending upon the context, the use of the term “comprises” or “comprising” may also be taken to encompass or include the meaning “consists essentially of” or “consisting essentially of,” and may also be taken to include the meaning “consists of’ or “consisting of.”

The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each aspect or exemplary embodiment of the invention as set out herein are also to be read as applicable to any other aspect or exemplary embodiments of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each exemplary embodiment of the invention as interchangeable and combinable between different exemplary embodiments.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiments). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A heat exchanger for use in a central heating system, the heat exchanger comprising:

internal pipework adapted for receiving a heat transfer fluid in use;

2. The heat exchanger according to claim 1, comprising a bleed valve located in an upper region of the heat exchanger in use.

3. The heat exchanger according to claim 1 or claim 2, wherein the drain opening faces substantially vertically downwards from the heat exchanger in use.

4. The heat exchanger according to any preceding claim, wherein the drain opening is located in a lowest point on the heat exchanger in use.

5. The heat exchanger according to any preceding claim, wherein the heat exchanger comprises a threaded connector within or surrounding the drain opening, the threaded connector adapted for engaging with a drain valve.

6. The heat exchanger according to any preceding claim, wherein the inlet pipe opening and the outlet pipe opening are arranged in the lower region of the heat exchanger in use.

7. The heat exchanger according to claim 6, wherein the drain opening is located adjacent to the inlet pipe opening or the outlet pipe opening.

8. The heat exchanger according to any preceding claim, comprising a removable blanking cap located in the drain opening, wherein the removable blanking cap closes and seals the drain opening to prevent the passage of said heat transfer fluid out of the heat exchanger through the drain opening, in use.

9. The heat exchanger according to claim 8, wherein the blanking cap comprises a plug attached to the blanking cap with a retainer.

10. The heat exchanger according to any preceding claim, comprising a drain valve located in the drain opening, the drain valve adapted to selectively allow or prevent the passage of said heat transfer fluid out of the heat exchanger through the drain opening, in use.

11. The heat exchanger according to any preceding claim, wherein the drain valve comprises a connector adapted for engagement with a hose.

12. A method of manufacturing a heat exchanger according to any one of claims 1-11, the method comprising the steps of:

a) providing a heat exchanger comprising:

internal pipework adapted for receiving a heat transfer fluid in use;

13. The method according to claim 12, wherein step b) involves inserting a threaded connector into the drain opening.

14. The method according to claim 12, wherein step b) involves attaching a threaded connector onto the heat exchanger and around the drain opening.

15. A method of removing a heat transfer fluid from a heat exchanger, the heat exchanger comprising a bleed valve and a drain valve, the drain valve located in a lower region of the heat exchanger in use, the method comprising the steps of:

16. The heat exchanger or method of any preceding claim, wherein the heat exchanger is a domestic radiator.