EP1525423A2

EP1525423A2 - A device and a method for removing dissolved gases from a liquid heat exchange medium in a heat exchange system and a heat exchange system

Info

Publication number: EP1525423A2
Application number: EP03700981A
Authority: EP
Inventors: Humphrey O'leary; Marianne Keane; Declan John Keane; Paul John Murphy; Thomas Mann; Gerard O'brien; Carl Christian Steinborn; Michael Gerard Tangney; Michael Kevin Winkle; Sean Kayenagh
Original assignee: Bodenhill Properties Ltd
Current assignee: Bodenhill Properties Ltd
Priority date: 2002-01-21
Filing date: 2003-01-21
Publication date: 2005-04-27
Also published as: WO2003060384A2; AU2003202123A1; WO2003060384A3; IES20030026A2

Abstract

A device (10) for removing dissolved air and oxygen from water heat exchange medium of a heat exchange system (1) comprises a housing (11) defining a pressure reduction chamber (12). An upper inlet port (54) and a lower outlet port (55) connect the pressure reduction chamber (12) to flow and return pipes (14, 15) respectively of a heat source circuit (3), and lower inlet ports (60, 61) and upper outlet ports (58, 59) connect the pressure reduction chamber (12) to flow and return pipes (16, 17) of first and second heat exchange circuits (4, 5) of the heat exchange system (1). The pressure reduction chamber (12) is sized and the inlet ports (54, 60, 61) are located so that water heat exchange medium entering the pressure reduction chamber (12) expands, thereby reducing the pressure of the water heat exchange medium and releasing dissolved gases from the water heat exchange medium. The released gases are vented through the upper inlet port (54) to a header tank (25) to atmosphere.

Description

"A device and a method for removing dissolved gases from a liquid heat exchange medium in a heat exchange system, and a heat exchange system"

The present invention relates to a device for removing dissolved gases from a liquid heat exchange medium of a heat exchange system, whereby the heat exchange system is of the type comprising a heat source and a heat exchanger, and the liquid heat exchange medium is circulated between the heat source and the heat exchanger for transferring heat from the heat source to the heat exchanger. The invention also relates to a heat exchange system comprising the device for removing dissolved gases from the liquid heat exchange medium in the heat exchange system, and to a method for removing dissolved gases from a liquid heat exchange medium of a heat exchange system.

Such heat exchange systems typically comprise a heat source, for example, a boiler and a plurality of heat exchangers, such as radiators connected through a circulating circuit to the boiler. Liquid heat exchange medium, typically water, is circulated from the boiler through the radiators through flow and return pipes of the circulating circuit. A pump in one of the pipes of the circulating circuit circulates the liquid heat exchange medium through the circulating circuit and in turn through the boiler and the radiators for transferring heat from the boiler to the radiators. The radiators typically are supported on walls of rooms for space heating. Such heat exchange systems may also include a separate circuit for heating an indirect hot water tank for providing domestic hot water. Additionally, in many cases such heat exchange systems may include more than one heat source, for example, a gas or oil fired boiler, and a back boiler located in a fireplace. Such heat exchange systems may also include a number of separate heat exchange circuits, each including a plurality of radiators for heating different zones in a building or the like, as well as a circuit for heating an indirect tank of a domestic hot water system. Indeed, such heat exchange systems may also include a circuit which includes a heat exchanger for heating water of a swimming pool, and may include one or more circuits comprising one or more under floor heat exchangers for circulating the liquid heat exchange medium through the under floor heat exchangers. In all such systems the liquid heat exchange medium, such as water, includes dissolved gases, for example, air, and in particular, oxygen. Such dissolved oxygen is typically referred to as free oxygen, and in general, is difficult to remove. Dissolved gases, in particular, free oxygen in a water heat exchange medium causes many problems. In particular, the dissolved gases significantly reduce the heat transfer efficiency of the heat exchange system. They lead to excessive noise, air locks, and cavitation in the circulating pump or pumps, as well as corrosion within the system which leads to an accumulation of sludge in the boiler or boilers, and in the radiators, thus further reducing the heat transfer efficiency of the system.

Furthermore, when free oxygen and other gases are released from the water heat exchange medium within the system, and the free oxygen is circulated with the water heat exchange medium, as well as leading to corrosion within the system, also lead to significant variation in the operating temperature between radiators. It is not unusual to find a 40% variation in operating temperature between radiators in the same heat exchange circuit. All these problems combine to significantly increase the fuel consumption required to operate the heat exchange system.

There is therefore a need for a device and a method for removing dissolved gases from a liquid heat exchange medium of a heat exchange system for minimising these problems.

The present invention is directed towards providing such a device and a method, and the invention is also directed towards a heat exchange system comprising the device.

According to the invention there is provided a device for removing dissolved gases in a liquid heat exchange medium of a heat exchange system of the type comprising a heat source and a heat exchanger, the liquid heat exchange medium being circulated between the heat source and the heat exchanger for transferring heat from the heat source to the heat exchanger, characterised in that the device comprises a housing defining a pressure reduction chamber for accommodating the liquid heat exchange medium therethrough, at least one inlet port for connecting the device into the heat exchange system and for accommodating the liquid heat exchange medium into the pressure reduction chamber from the heat exchange system, at least one outlet port for connecting the device into the heat exchange system for returning the liquid heat exchange medium from the pressure reduction chamber to the heat exchange system, the pressure reduction chamber providing a sudden step change increase in the transverse cross-sectional area presented to the heat exchange medium between the inlet port and the outlet port sufficient for reducing the pressure in the liquid heat exchange medium flowing through the pressure reduction chamber for releasing dissolved gases from the heat exchange medium, and a venting means from the pressure reduction chamber for venting gases released from the heat exchange medium.

In one embodiment of the invention the volume of the pressure reduction chamber is such as to facilitate the release of dissolved gases from the liquid heat exchange medium.

In another embodiment of the invention the volume of the pressure reduction chamber is such as to allow sufficient dwell time to the liquid heat exchange medium therein for at least some of the dissolved gases released from the heat exchange medium to exit through the venting means.

In a further embodiment of the invention the step change in the transverse cross- sectional area presented to the liquid heat exchange medium between the inlet port and the outlet port is sufficient for inducing turbulence in the heat exchange medium for further facilitating release of dissolved gases from the heat exchange medium in the pressure reduction chamber.

In one embodiment of the invention the housing comprises a side wall.

In another embodiment of the invention a turbulence inducing means is located in the pressure reduction chamber for inducing turbulence in the liquid heat exchange medium in the pressure reduction chamber for further facilitating the release of dissolved gases from the heat exchange medium.

Preferably, the turbulence inducing means is located spaced apart from at least one of the at least one inlet port.

Advantageously, the turbulence inducing means extends into the pressure reduction chamber from the housing, and is located spaced apart from at least one of the at least one inlet port.

In one embodiment of the invention the turbulence inducing means comprises an elongated turbulence inducing rib extending longitudinally along the side wall.

Preferably, the turbulence inducing means extends from the side wall into the pressure reduction chamber a distance between 1mm and 5mm. Advantageously, the turbulence inducing means is of width in the range of 2mm to 4mm.

In one embodiment of the invention one of the at least one inlet ports is located in the side wall, and the turbulence inducing means extends from the side wall spaced apart from the inlet port located in the side wall.

Preferably, the turbulence inducing means is located relative to the inlet port so that the perpendicular distance from the turbulence inducing means to the centre of the inlet port lies in the range of one times the diameter of the inlet port to three times the diameter of the inlet port.

Advantageously, the turbulence inducing means is located relative to the inlet port so that the perpendicular distance from the turbulence inducing means to the centre of the inlet port is approximately twice the diameter of the inlet port.

In one embodiment of the invention the turbulence inducing means extends along the side wall for a distance corresponding to at least the diameter of the inlet port. In another embodiment of the invention the turbulence inducing means extends along the side wall for a distance corresponding to at least three times the diameter of the inlet port.

In a further embodiment of the invention the turbulence inducing means extends from a line extending perpendicularly from the tubular inducing means to the centre of the inlet port on opposite first and second sides of the said line a distance corresponding to at least one and a half diameters of the inlet port.

Preferably, the turbulence inducing means extends for a distance from the first side of the said line extending perpendicularly from the turbulence inducing means to the centre of the inlet port a distance greater than the distance from which the turbulence inducing means extends from the second side of the said line.

Advantageously, the turbulence inducing means extends on the first side of the line extending perpendicularly from the turbulence inducing means to the centre of the inlet port for a distance corresponding to at least two diameters of the inlet port.

In one embodiment of the invention the turbulence inducing means extends on the first side of the line extending perpendicularly from the turbulence inducing means to the centre of the inlet port for a distance corresponding to at least three diameters of the inlet port.

In another embodiment of the invention the turbulence inducing means extends on the second side of the line extending perpendicularly from the turbulence inducing means to the centre of the inlet port for a distance corresponding to at least two diameters of the inlet port.

In one embodiment of the invention a pair of inlet ports are located in the side wall, and the turbulence inducing means is located between the respective inlet ports, and preferably, the turbulence inducing means extends perpendicularly to a line joining the centres of the two inlet ports. Advantageously, the turbulence inducing means is located equi-spaced between the two inlet ports.

In one embodiment of the invention the side wall is a cylindrical side wall, and the turbulence inducing means extends in a generally axial direction relative to the cylindrical side wall.

In one embodiment of the invention the cylindrical side wall defines a geometrical longitudinally extending central axis.

In another embodiment of the invention the device is adapted for connecting into the heat exchange system with the central axis extending substantially vertically.

Preferably, the housing comprises a top wall and a spaced apart bottom wall, the top and bottom walls extending transversely of the side wall, and the side wall extends between the top and bottom walls.

Advantageously, each inlet port located in the side wall of the housing is located in the side wall towards the bottom wall thereof.

Ideally, an inlet port is located in the top wall.

In one embodiment of the invention the top wall is of dome shape, and the inlet port is located substantially centrally in the top wall.

In another embodiment of the invention the venting means is located in the top wall.

In a further embodiment of the invention the inlet port in the top wall acts as the venting means.

In one embodiment of the invention an outlet port is located in the side wall cooperating with the inlet port in the top wall for connecting the device into a heat exchange system. Preferably, the outlet port which co-operates with the inlet port in the top wall is located towards the bottom wall.

In one embodiment of the invention an outlet port is located in the side wall corresponding to each inlet port in the side wall for co-operating with the said corresponding inlet port for connecting the device into the central heat exchange system.

Preferably, each outlet port in the side wall corresponding to an inlet port in the side wall is located spaced apart from and at a level above the corresponding inlet port. Advantageously, the side wall adjacent each inlet port extends substantially transversely of the direction of flow of heat exchange medium from the inlet port into the pressure reduction chamber.

In an alternative embodiment of the invention the side wall of the housing comprises at least one planar side wall.

In a further embodiment of the invention the turbulence inducing means comprises an adjacent wall extending from the planar side wall.

In another embodiment of the invention two of the walls extending from the planar side wall form side walls of the housing.

In another embodiment of the invention each side wall is a planar side wall.

In a further embodiment of the invention each side wall extending from a planar side wall extends from the planar side wall at a location spaced apart from an adjacent one of the inlet ports a sufficient distance for providing the sudden step change in the transverse cross-sectional area presented to the heat exchange medium.

In one embodiment of the invention the periphery of each inlet port is spaced apart from the side wall to which it is closest a distance of at least 10mm. In another embodiment of the invention the periphery of each inlet port is spaced apart from the side wall to which it is closest a distance of at least 12.5mm.

In a further embodiment of the invention the periphery of each inlet port is spaced apart from the side wall to which it is closest a distance of at least 15mm.

In a still further embodiment of the invention the periphery of each inlet port is spaced apart from the side wall to which it is closest a distance of at least 25mm.

In a still further embodiment of the invention each inlet port is of diameter approximately 25mm, and each inlet port is spaced apart from the side wall to which it is closest a distance, centre to side wall of at least 45mm.

In one embodiment of the invention each inlet port is of diameter approximately 25mm, and each inlet port is spaced apart from the side wall to which it is closest a distance, centre to side wall of at least 50mm.

In another embodiment of the invention each inlet port is of diameter approximately 25mm, and each inlet port is spaced apart from the side wall to which it is closest a distance, centre to side wall of at least 60mm.

In a further embodiment of the invention each inlet port is of diameter approximately 25mm, and each inlet port is spaced apart from the side wall to which it is closest a distance, centre to side wall of at least 70mm.

In one embodiment of the invention the housing is a six-sided housing having six planar walls defining six inner planar wall surfaces forming the pressure reduction chamber, and in another embodiment of the invention the pressure reduction chamber is parallelepiped, while in a still further embodiment of the invention the pressure reduction chamber is cubic. In one embodiment of the invention at least one inlet port and one outlet port are provided in the same planar wall of the housing.

In another embodiment of the invention the minimum distance between peripheral edges of adjacent inlet and outlet ports in the same wall is at least 154mm.

In a further embodiment of the invention the minimum distance between peripheral edges of adjacent inlet and outlet ports in the same wall is at least 164mm.

In a still further embodiment of the invention the minimum distance between peripheral edges of adjacent inlet and outlet ports in the same wall is at least 175mm.

In a still further embodiment of the invention the minimum distance between the peripheral edges of adjacent inlet ports on the same wall is at least 40mm.

In another embodiment of the invention the minimum distance between the peripheral edges of adjacent inlet ports on the same wall is at least 75mm.

In a further embodiment of the invention the minimum distance between the peripheral edges of adjacent inlet ports on the same wall is at least 115mm.

In one embodiment of the invention a plurality of inlet ports are provided to the pressure reduction chamber, and a plurality of outlet ports are provided from the pressure reduction chamber for connecting a plurality of circuits of the heat exchange system, at least one of the circuits being a heat source circuit comprising a heat source for heating the liquid heat exchange medium, and at least one of the circuits being a heat exchange circuit comprising a heat exchanger for transferring heat from the liquid heat exchange medium of the heat exchange system.

In another embodiment of the invention the volume of the pressure reduction chamber is sufficient for facilitating mixing of the liquid heat exchange medium in the pressure reduction chamber from respective circuits of the heat exchange system.

In a further embodiment of the invention the volume of the pressure reduction chamber is sufficient for facilitating mixing of the liquid heat exchange medium in the pressure reduction chamber from each operational heat exchange circuit with the liquid heat exchange medium from each operational heat source circuit.

In a still further embodiment of the invention each outlet port for returning the liquid heat exchange medium to a heat source circuit is located relative to the inlet port through which the liquid heat exchange medium is received into the pressure reduction chamber from the heat source circuit so that the direction of flow of the liquid heat exchange medium from the pressure reduction chamber is at 90° to the direction of flow of the liquid heat exchange medium into the pressure reduction chamber.

In a further embodiment of the invention the inlet and outlet ports for connecting the device to each heat exchange circuit are arranged so that the direction of flow of the liquid heat exchange medium from the pressure reduction chamber to the heat exchange circuit is at 180° to the direction of flow of the liquid heat exchange medium into the pressure reduction chamber from the heat exchange circuit.

In one embodiment of the invention the liquid heat exchange medium of the heat exchange system is a water heat exchange medium.

In another embodiment of the invention the device is adapted for releasing dissolved oxygen from the liquid water heat exchange medium.

Additionally the invention provides a heat exchange system comprising a heat source, and at least one heat exchanger, and a circulating system for circulating a liquid heat exchange medium between the heat source and the heat exchanger, and a device according to the invention for removing dissolved gases from the liquid heat exchange medium, characterised in that the device is connected into the circulating system so that the circulating heat exchange medium circulates through the pressure reduction chamber of the device for reducing the pressure of the liquid heat exchange medium in the pressure reduction chamber for releasing dissolved gases from the liquid heat exchange medium.

In one embodiment of the invention the heat exchange system comprises at least one heat source circuit, each heat source circuit comprising a heat source for heating the liquid heat exchange medium, and at least one heat exchange circuit, each heat exchange circuit comprising at least one heat exchanger for transferring heat from the liquid heat exchange medium.

In another embodiment of the invention each heat source circuit comprises a flow pipe and a return pipe, the flow pipe of each heat source circuit being connected to the inlet port in the top wall of the housing of the device for delivering heat exchange medium into the pressure reduction chamber, and the return pipe of each heat source circuit being connected to a corresponding one of the outlet ports in the side wall of the housing co-operating with the inlet port in the top wall for returning heat exchange medium to the heat source circuit.

In another embodiment of the invention each heat exchange circuit comprises a flow pipe and a return pipe, the return pipe of each heat exchange circuit being connected to a corresponding one of the inlet ports in the side wall of the housing of the device for returning heat exchange medium to the pressure reduction chamber, and the flow pipe of each heat exchange circuit being connected to a corresponding one of the outlet ports in the side wall of the housing of the device for receiving heat exchange medium from the pressure reduction chamber.

In one embodiment of the invention each heat exchanger comprises a heat exchanger for space heating.

In another embodiment of the invention in that at least one of the heat exchangers comprises a heat exchanger for providing under floor heating. In a further embodiment of the invention at least one of the heat exchangers comprises a heat exchanger for heating water for a swimming pool.

In one embodiment of the invention at least one of the heat exchangers is a heat exchanger for heating domestic hot water.

In another embodiment of the invention the circulating system comprises a primary circulating means in each heat source circuit for circulating the liquid heat exchange medium through the heat source circuit between the heat source and the pressure reduction chamber of the device.

In another embodiment of the invention the circulating system comprises a secondary circulating means in each heat exchange circuit for circulating the liquid heat exchange medium through the heat exchange circuit between the pressure reduction chamber and each heat exchanger in the heat exchange circuit.

Additionally the invention provides a method for removing dissolved gases in a liquid heat exchange medium of a heat exchange system of the type which comprises a heat source and a heat exchanger, the liquid heat exchange medium being circulated between the heat source and the heat exchanger for transferring heat from the heat source to the heat exchanger, characterised in that the method comprises the step of passing the liquid heat exchange medium into a pressure reduction chamber having an inlet port for receiving the liquid heat exchange medium from the heat exchange system and an outlet port for returning the liquid heat exchange medium to the heat exchange system, and the pressure reduction chamber provides a sudden step change increase in the transverse cross-sectional area presented to the liquid heat exchange medium between the inlet port and the outlet port for reducing the pressure of the liquid heat exchange medium flowing through the pressure reduction chamber sufficient for releasing dissolved gases from the liquid heat exchange medium, and venting the dissolved gases from the pressure reduction chamber. Preferably, the method comprises the further step of providing the pressure reduction chamber with a volume such as to facilitate the release of dissolved oxygen from the liquid heat exchange medium.

In one embodiment of the invention the volume of the pressure reduction chamber is such as to allow sufficient dwell time for the liquid heat exchange medium therein for venting at least some of the dissolved gases released from the liquid heat exchange medium therefrom.

In another embodiment of the invention the method further comprises the step of inducing turbulence in the liquid heat exchange medium in the pressure reduction chamber for further facilitating the release of dissolved gases from the liquid heat exchange medium.

In a further embodiment of the invention a turbulence inducing means is provided in the pressure reduction chamber for inducing turbulence in the heat exchange medium.

In one embodiment of the invention the turbulence inducing means is located spaced apart from one of the inlet ports to the pressure reduction chamber.

In another embodiment of the invention the turbulence inducing means is provided by an elongated rib extending along a side wall of a housing defining the pressure reduction chamber.

In a still further embodiment of the invention the turbulence inducing means is formed by a side wall of the housing adjacent to the side wall in which the inlet port is located.

The advantages of the invention are many. A particularly important advantage of the invention is that the device according to the invention removes or significantly reduces dissolved gases in a liquid heat exchange medium of a heat exchange system. The dissolved gases are removed from the liquid heat exchange medium by virtue of the fact that the pressure reduction chamber provides a sudden step change increase in the transverse cross-sectional area presented to the heat exchange medium as it flows through each inlet port into the pressure reduction chamber. By providing the sudden step change increase in the transverse cross- sectional area presented to the liquid heat exchange medium, the heat exchange medium as it enters the pressure reduction chamber expands, thereby reducing the pressure of the liquid heat exchange medium. The reduction in pressure in the liquid heat exchange medium causes dissolved gases in the heat exchange medium to be released. These released dissolved gases are then vented through the venting means from the pressure reduction chamber.

The device according to the invention makes use of the principle that dissolved gases in a liquid such as water, are released when the pressure of the liquid is reduced at constant temperature. The amount of dissolved gases which are released by a change in pressure at constant temperature is a function of the pressure drop. However, the device according to the invention also makes use of the principle that dissolved gases are released from a liquid such as water when the temperature of the liquid is increased at constant pressure. Where the device is used to connect a heat exchange circuit with a heat source circuit, the temperature of the liquid heat exchange medium being returned to the pressure reduction chamber from the heat exchange circuit where heat has been transferred from the liquid heat exchange medium is raised as the heat exchange medium enters the pressure reduction chamber from the heat exchange circuit, thereby further enhancing the release of dissolved gases from the heat exchange medium, due to the fact that as the heat exchange medium is being returned to the pressure reduction chamber, the pressure of the heat exchange medium drops and the temperature increases simultaneously. The simultaneous drop in pressure and rise in temperature of the liquid heat exchange medium further increases the rate of release of dissolved gases from the liquid heat exchange medium. The provision of a turbulence inducing means in the pressure reduction chamber induces turbulence into the liquid heat exchange medium in the pressure reduction chamber, and this, it has been found, further enhances the release of dissolved gases from the liquid heat exchange medium, and additionally, facilitates in rapid transfer of the released dissolved gases to and through the venting means from the pressure reduction chamber. Where the housing forming the pressure reduction chamber comprises a plurality of planar side walls, the adjacent planar side walls to each planar side wall act as turbulence inducing means. Where the housing forming the pressure reduction chamber comprises a cylindrical side wall, a relatively small turbulence inducing rib extending axially along the side wall adjacent to but spaced apart from an inlet port, in general, is sufficient for inducing the appropriate degree of turbulence to the heat exchange medium in the pressure reduction chamber. It is believed that the turbulence inducing rib projecting from the cylindrical side wall deflects the liquid heat exchange medium flowing circumferentially along the side wall away from the side wall and radially into the pressure reduction chamber, for in turn inducing the appropriate degree of turbulence in the liquid heat exchange medium within the pressure reduction chamber.

Where the liquid heat transfer medium is water, since water in general comprises dissolved air and dissolved oxygen, the advantages of the device according to the invention are even greater, since by releasing the dissolved gases from the water heat exchange medium, and in particular, dissolved air and dissolved oxygen, the corrosive effect of the dissolved oxygen in the water heat exchange medium is removed. The presence of dissolved oxygen in a water heat exchange medium leads to internal corrosion of heat exchangers, boilers, and depending on the material of the pipework of the circulating system, may also result in internal corrosion of the pipework.

By removing dissolved gases from the liquid heat exchange medium, the efficiency of the heat exchange system is significantly increased, since cavitation in the pump or pumps of the circulating system is eliminated due to the fact that dissolved gases are removed from the heat exchange medium. It is well known that the presence of dissolved gases in a liquid heat exchange medium, and in particular, in a water heat exchange medium, leads to cavitation in a pump or pumps of a circulating system of a heat exchange system. By reducing and in most cases virtually eliminating cavitation, pumps of the circulating system operate significantly more efficiently, thereby enhancing the efficiency of the heat exchange system, and furthermore, permitting the use of smaller pumps.

Heat transfer efficiency from the boiler to the liquid heat exchange medium is significantly increased by the removal of dissolved gases from the liquid heat exchange medium, and furthermore, heat transfer efficiency between the liquid heat exchange medium and the heat exchangers is likewise similarly significantly increased due to the removal of dissolved gases in the liquid heat exchange medium. By virtue of the fact that the heat transfer efficiency between the boiler or boilers and the liquid heat exchange medium, and also between the liquid heat exchange medium and the heat exchangers, the heat exchangers can operate at a significantly increased operating temperature, and furthermore, the operating temperature of the heat exchangers can be controlled within a relatively narrow tolerance of approximately 3°C.

It has also been found that by removing dissolved gases from the heat exchange medium the flow rate of the heat exchange medium through the system can be significantly increased, and in the case of a water heat exchange medium, it has been found that the increase in flow rate of the water heat exchange medium through the heat exchange system can be increased by up to 21%. This, thus, leads to a significant increase in the overall operating efficiency of the heat exchange system, and additionally, permits operation of the heat exchangers at a temperature closer to the temperature of the heat exchange medium as it leaves the boiler, thereby minimising the temperature drop between the boiler and the heat exchangers. This, thus, leads to a significant increase in the overall efficiency of the heat exchange system, which in turn leads to a significant reduction in fuel consumption. Furthermore, by minimising the temperature drop between the boiler and each heat exchanger, and furthermore, by increasing the flow rate of the heat exchange medium through the heat exchange system, recovery of the heat exchange system is significantly improved. For example, the recovery of the heat exchange system after a bath or a shower is significantly increased.

It has also been found that the pump or pumps of the circulating system may be operated at a lower setting while maintaining the same heat output of the heat exchange system, thereby further enhancing the operating efficiency of the heat exchange system. It has also been found that increased throughput of water through a swimming pool filtration system can be achieved by using the device according to the invention, and such increases can be up to 23%.

It is desirable that the volume of the pressure reduction chamber should be matched to the volume and the flow rate of the heat exchange system in order to allow sufficient dwell time for the liquid heat exchange medium in the pressure reduction chamber to allow the released dissolved gases from the liquid heat exchange medium to be vented through the venting means from the pressure reduction chamber. Additionally, where mixing of cooler returning liquid heat exchange medium with hotter liquid heat exchange medium flowing into the pressure reduction chamber takes place, the volume of the pressure reduction chamber should be such as to facilitate adequate mixing of the cooler and hotter liquid heat exchange media within the pressure reduction chamber, in order to allow heating of the cooler heat exchange medium by the hotter heat exchange medium, for further enhancing the release of dissolved gases from the cooler returning heat exchange medium as the temperature of the cooler returning heat exchange medium increases and its pressure drops.

Additionally, the device provides a simple, efficient system of removing dissolved gases from a liquid heat exchange medium, and in particular, for removing dissolved oxygen from a water heat exchange medium, which otherwise is particularly difficult to remove.

The invention will be more clearly understood from the following description of some preferred embodiments thereof, which are given by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 is a circuit diagram of a heat exchange system according to the invention incorporating a device also according to the invention for removing dissolved gases from a liquid heat exchange medium of the heat exchange system,

Fig. 2 is a perspective view of the device of Fig. 1 for removing dissolved gases from the liquid heat exchange medium of the heat exchange system,

Fig. 3 is a cutaway perspective view of a portion of the device of Fig. 2,

Fig. 4 is a front elevational view of the device of Fig. 2,

Fig. 5 is side elevational view of the device of Fig. 2,

Fig. 6 is a perspective view of a portion of the device of Fig. 2,

Fig. 7 is a perspective view of another portion of the device of Fig. 2,

Fig. 8 is a top plan view of the device of Fig. 2,

Fig. 9 is a transverse cross-sectional end elevational view of a portion of the device of Fig. 2 on the line IX-IX of Fig. 8,

Fig. 10 is a transverse cross-sectional side elevational view on the line X-X of Fig. 8 of the device of Fig. 2,

Fig. 1 1 is an enlarged plan view of a detail of the device of Fig. 2,

Fig. 12 is a circuit diagram of a heat exchange system according to another embodiment of the invention incorporating the device of Fig. 2,

Fig. 13 is a circuit diagram of a heat exchange system according to a further embodiment of the invention incorporating the device of Fig. 2,

Fig. 14 is a circuit diagram of a heat exchange system according to a further embodiment of the invention incorporating the device of Fig. 2,

Fig. 15 is a circuit diagram of a heat exchange system according to another embodiment of the invention incorporating a device also according to another embodiment of the invention for removing dissolved gases from a liquid heat exchange medium of the heat exchange system,

Fig. 16 is a top front perspective view of the device of Fig. 15,

Fig. 17 is a cutaway top perspective view of the device of Fig. 15,

Fig. 18 is a top side end perspective view of the device of Fig. 15,

Fig. 19 is another perspective view of the device of Fig. 15,

Fig. 20 is a circuit diagram of a heat exchange system according to another embodiment of the invention comprising the device of Fig. 16 for removing dissolved gases in a liquid heat exchange medium of a heat exchange system,

Fig. 21 is a top front perspective view of a device according to another embodiment of the invention for removing dissolved gases from a liquid heat exchange medium of a heat exchange system,

Fig. 22 is a top front perspective view of a device according to another embodiment of the invention for removing dissolved gases from a liquid heat exchange medium of a heat exchange system, and

Fig. 23 is a circuit diagram of a heat exchange system according to a further embodiment of the invention incorporating the devices of Figs. 16 and 21.

Referring to the drawings and initially to Figs. 1 to 13 thereof, there is illustrated a heat exchange system according to the invention, indicated generally by the reference numeral 1. In this embodiment of the invention the heat exchange system is suitable for domestic water heating, and is also suitable for space heating a house in which the space heating is divided into two zones, for example, a first zone which may be the ground floor of the house, and a second zone which may be the first floor of the house. The heat exchange system 1 comprises a heat source circuit 3 and two heat exchange circuits, namely, a first heat exchange circuit 4 for space heating the first zone, and a second heat exchange circuit 5 for space heating the second zone. The heat source circuit 3 comprises a heat source, in this embodiment of the invention a boiler 6, which may be a gas fired or an oil fired boiler. Each first and second heat exchange circuit 4 and 5 comprises a plurality of heat exchangers, namely, wall mounted radiators 7. Although only two radiators 7 are illustrated in the first heat exchange circuit 4 and one radiator 7 is illustrated in the second heat exchange circuit 5, it will be readily apparent to those skilled in the art that any appropriate number of radiators 7 will be provided in the first and second heat exchange circuits 4 and 5. Heat is transferred between the boiler 6 and the radiators 7 by a liquid heat transfer medium, which in this embodiment of the invention is a water heat transfer medium.

A device also according to the invention, indicated generally by the reference numeral 10, for removing dissolved gases, and in particular, dissolved air and oxygen in the water heat exchange medium connects the first and second heat exchange circuits 4 and 5 with the heat source circuit 3. The device 10 as will be described in detail below comprises a housing 11 which defines a pressure reduction chamber 12 for accommodating water heat exchange medium therethrough, and within which the dissolved gases are released from the water heat exchange medium, as will be described below. The heat source circuit 3 comprises a flow pipe 14 which connects a hot water flow outlet of the boiler 6 to the pressure reduction chamber 12 of the device 10. A return pipe 15 from the pressure reduction chamber 12 of the device 10 to a return water inlet of the boiler 6 returns water heat exchange medium from the pressure reduction chamber 12 to the boiler 6. Each first and second heat exchange circuit 4 and 5 comprises a flow pipe 16 through which hot water heat exchange medium from the pressure reduction chamber 12 of the device 10 is delivered to the radiators 7, and a return pipe 17 from which water heat exchange medium from the radiators 7 is returned to the pressure reduction chamber 12 of the device 10.

A primary circulating means, in this embodiment of the invention a primary circulating pump 18 is located in the return pipe 15 of the heat source circuit 3 for circulating water heat exchange medium between the heat source circuit 3 and the pressure reduction chamber 12 of the device 10. Secondary circulating means, namely, secondary circulating pumps 19 located in the return pipes 17 of the first and second heat exchange circuits 4 and 5 circulate water heat exchange medium between the pressure reduction chamber 12 of the device 10 and the radiators 7.

A heat exchanger, in this embodiment of the invention an indirect hot water tank 20 for providing domestic hot water, is connected in series in the flow pipe 14 of the heat source circuit 3. The indirect hot water tank 20 comprises a hot water cylinder 21 having an indirect heating coil 22 for heating domestic hot water in the hot water cylinder 21. An inlet 23 to the heating coil 22 receives the water heat exchange medium from the boiler 6 through the flow pipe 14, and an outlet 24 from the heating coil 22 returns water heat exchange medium to the flow pipe 14 which in turn is delivered to the pressure reduction chamber 12 of the device 10.

A header tank 25 is connected into the heat exchange system 1 through a supply pipe 26 for pressurising the heat exchange system 1 and for providing top-up water for the heat exchange system 1. The supply pipe 26 is teed into the flow pipe 14 at 27 between the indirect hot water tank 20 and the device 10. An expansion pipe 28 is teed off from the flow pipe 14 of the heat source circuit 3 for accommodating expansion of the water heat exchange medium from the heat exchange system 1 to the header tank 25. The expansion pipe 28 is teed off at 29 from the flow pipe 14 between the boiler 6 and the indirect hot water tank 20.

The operation of the heat exchange system 1 is as follows. The primary circulating pump 18 is wired with the boiler 6 so that when the boiler 6 is operating, the primary circulating pump 18 also operates for circulating water heat exchange medium through the heat source circuit 3 between the boiler 6 and the pressure reduction chamber 12 of the device 10. The circulating water heat exchange medium from the boiler 6 to the device 10 flows through the indirect heating coil 22 for heating domestic water in the hot water cylinder 21. As heat is required from the radiators 7 in the respective first and second heat exchange circuits 4 and 5, the appropriate one or both of the secondary circulating pumps 19 are activated for circulating the water heat exchange medium from the pressure reduction chamber 12 of the device 10 through the radiators 7 for heating the radiators 7 for space heating.

Referring now to Figs. 2 to 11 , the device 10 will now be described. The housing 11 of the device 10 is a cylindrical housing of plastics material having a cylindrical side wall 30 closed at its lower end by a bottom wall 31 which is concave when viewed from above, and closed at its upper end by a dome shaped top wall 32 to form the pressure reduction chamber 12. The housing 11 is two piece housing of injection moulded plastics material formed in two halves, namely, a lower half 34 and an upper half 35 which are sealably clamped together by a V-band 37. Radially outwardly extending clamping flanges 38 and 39 extend circumferentially around the lower and upper halves 34 and 35, respectively, for engaging the V-band 37 for retaining the lower and upper halves 34 and 35 sealably clamped together. The clamping flanges 38 and 39 are chamfered at 40 and 41, respectively, for cooperating with the V-band 37 so that as the V-band 37 is tightened around the clamping flanges 38 and 39, the flanges 38 and 39 are drawn tightly together for forming a sealed joint. The cylindrical side wall 30 defines a central geometric longitudinally extending central axis 44. Longitudinally extending external reinforcing ribs 45 extend along the outer surface of the side wall 30 for strengthening the side wall 30. Upper arcuate radially extending reinforcing ribs 47 and upper circumferentially extending reinforcing ribs 48 strengthen the top wall 32. Lower arcuate radially extending reinforcing ribs 49 and lower circumferentially extending reinforcing ribs 50 strengthen the bottom wall 31 and provide a ground engaging support for the device 10.

An upper inlet port 54 centrally located in the top wall 32 and coaxial with the central axis 44 accommodates water heat exchange medium from the flow pipe 14 of the heat source circuit 3 into the pressure reduction chamber 12. First and second lower outlet ports 55 and 56 extending from the side wall 30 in the lower half 34 of the housing 11 return water heat exchange medium from the pressure reduction chamber 12 to return pipes of the heat source circuits where two heat source circuits comprising respective boilers are provided. However, in this embodiment of the invention since only one heat source circuit 3 is provided, the first lower outlet port 55 is connected to the return pipe 15 of the heat source circuit 3 for returning water heat exchange medium from the pressure reduction chamber 12 to the boiler 6. The second lower outlet port 56 is blanked off. In the event that two heat source circuits were provided the flow pipes of the respective heat source circuits would be teed into the upper inlet port 54 and the return pipes of the heat source circuits would be connected, one each to the first and second lower outlet ports 55 and 56. Accordingly, the upper inlet port 54 and the first and second lower outlet ports 55 and 56 co-operate for connecting the device 10 into the heat exchange system 1.

A pair of upper outlet ports 58 and 59 extend from the cylindrical side wall 30 in the upper half 35 of the housing 11 for delivering water heat exchange medium from the pressure reduction chamber 12 to the flow pipes 16 of the first and second heat exchange circuits 4 and 5, respectively. A pair of lower inlet ports 60 and 61 extend from the side wall 30 of the lower half 34 of the housing 11 for receiving return water heat exchange medium into the pressure reduction chamber 12 from the return pipes 17 of the first and second heat exchange circuits 4 and 5, respectively. Accordingly, the upper outlet port 58 and the lower inlet port 60 co-operate with each other for connecting the device 10 into the heat exchange system 1 through the first heat exchange circuit 4, while the upper outlet port 59 and the lower inlet port 61 cooperate with each other for connecting the device 10 into the heat exchange system 1 through the second heat exchange circuit 5.

A turbulence inducing means for inducing turbulence in the water heat exchange medium in the pressure reduction chamber 12 comprises an elongated turbulence inducing rib 64 extending parallel to the central axis 44 along the inner surface of the cylindrical side wall 30 in the lower half 34 of the housing 11. The turbulence inducing rib 64 is located between and equi-distant from the lower inlet ports 60 and 61. The turbulence inducing rib 64 is of width w of approximately 2.5mm, and extends from the side wall 30 into the pressure reduction chamber 12 a distance s of approximately 3mm, see Figs. 9, 10 and 11. The length L of the turbulence inducing rib 64 is of length which lies between four and five times the diameter of one of the two lower inlet ports 60 and 61. In this embodiment of the invention each of the lower inlet ports 60 and 61 are of diameter of 28mm, and accordingly, the turbulence inducing rib 64 extends axially for a length L of 123mm approximately. The spacing centre to centre between the two lower inlet ports 60 and 61 is approximately equal to 4.5 diameters of one of the two lower inlet ports 60 and 61 , and is thus approximately 130mm. Thus, the perpendicular distance from the turbulence inducing rib 64 to the centre of the respective lower inlet ports 60 and 61 is approximately 65mm. In this embodiment of the invention the turbulence inducing rib 64 is located so that it extends axially upwardly above a line 65 joining the centres of the lower inlet ports 60 and 61 for a distance of just over two diameters of one of the lower inlet ports 60 and 61 , and extends downwardly below the line 65 for a similar distance. Thus, the turbulence inducing rib 64 extends for a distance of approximately 62mm downwardly below the line 65, and extends for a distance upwardly above the line 65 for a distance of approximately 62mm.

In this embodiment of the invention the diameter of the upper outlet ports 58 and 59 is similar to the diameter of the two lower inlet ports 60 and 61 , and each upper outlet port 58 and 59 is located and spaced vertically above its corresponding lower inlet port 60 and 61 a distance of 5.8 diameters of the lower inlet ports 60 and 61 , namely, a distance of 163mm, approximately.

Water heat exchange medium on entering the pressure reduction chamber 12 through the upper inlet port 54 is presented with a sudden step change increase in the transverse cross-sectional area from the diameter of the upper inlet port 54 to the diameter of the pressure reduction chamber 12, which causes the water heat exchange medium to expand as it enters the pressure reduction chamber 12, thus reducing the pressure of the water heat exchange medium as it enters the pressure reduction chamber 12. The reduction in pressure in the water heat exchange medium releases dissolved gases, in particular dissolved air and oxygen from the water heat exchange medium, which readily bubbles upwards in the pressure reduction chamber 12 and exits through the upper inlet port 54, which also acts as a venting means for venting the released dissolved gases from the water heat exchange medium from the pressure reduction chamber 12. In this embodiment of the invention it is important that the portion of the flow pipe 14 connecting the upper inlet port 54 to the supply pipe 26, and the supply pipe 26 should continuously rise to the header tank 25 in order to ensure a continuously rising path for venting the released dissolved gases from the water heat exchange medium from the pressure reduction chamber 12 to the header tank 25 from which the vented dissolved gases are thus released to atmosphere. In the event that the piping system from the upper inlet port 54 to the header tank 25 does not continuously rise, an automatic vent unit is connected to the flow pipe 14 just above the upper inlet port 54 for venting the released dissolved gases from the water heat exchange medium.

Return water heat exchange medium from the return pipes 17 of the first and second heat exchange circuits 4 and 5 on entering the pressure reduction chamber 12 through the lower inlet ports 60 and 61 is presented with a sudden step increase in cross-sectional area, and thus the return water heat exchange medium entering the pressure reduction chamber 12 through the lower inlet ports 60 and 61 expands, thus reducing the pressure of the return water heat exchange medium as it enters the pressure reduction chamber 12. The reduction in pressure of the return water heat exchange medium causes dissolved gases including air and oxygen to be released from the return water heat exchange medium into the pressure reduction chamber 12 which is vented through the upper inlet port 54. Additionally, the return water heat exchange medium being returned to the pressure reduction chamber 12 through the lower inlet ports 60 and 61 on entering the pressure reduction chamber 12 is heated, thereby raising the temperature of the return water heat exchange medium, which further facilitates in releasing dissolved gases from the water heat exchange medium.

The turbulence inducing rib 64 acts on the return water heat exchange medium being returned to the pressure reduction chamber 12 through the lower inlet ports 60 and 61 for inducing turbulence in the return water heat exchange medium in the pressure reduction chamber 12 which further facilitates and enhances the release of dissolved gases from the water heat exchange medium. The induced turbulence also facilitates rapid venting of the released dissolved gases from the pressure reduction chamber 12 through the upper inlet port 54. The turbulence inducing rib 64 induces turbulence in the return water heat exchange medium returning to the pressure reduction chamber 12 through the lower inlet ports 60 and 61 by virtue of the fact that some of the return water heat exchange medium on entering the pressure reduction chamber 12 commences to flow in a circumferential direction around the inner surface of the cylindrical side wall 30. The turbulence inducing rib 64 directs this water heat exchange medium away from the side wall 30 radially into the pressure reduction chamber 12, which induces the turbulence in the water heat exchange medium in the pressure reduction chamber 12.

Additionally, it is believed that flow water heat exchange medium flowing into the pressure reduction chamber 12 through the upper inlet port 54 commences to flow along the inner surface of the top wall 32, however, on reaching the cylindrical side wall 30 which extends downwardly from the top wall 32 the flow water heat exchange medium is directed downwardly away from the inner surface of the top wall 32, thereby also inducing additional turbulence in the pressure reduction chamber 12. Additionally, the first and second lower outlet ports 55 and 56 extend from the pressure reduction chamber 12 at an angle of 90° to the direction at which the upper inlet port 54 enters the pressure reduction chamber 12. Accordingly, water heat exchange medium passing through the pressure reduction chamber 12 from the upper inlet port 54 to the first and second lower outlet ports 55 and 56 is turned through an angle of 90°. This significantly increases turbulence within the pressure reduction chamber 12, thereby further enhancing the release of dissolved air and dissolved oxygen from the water heat exchange medium, and also facilitates rapid transfer of the released dissolved air and dissolved oxygen through the water heat exchange medium in the pressure reduction chamber 12 to the upper inlet port 54 for venting therethrough.

Further, the corresponding lower inlet and upper outlet ports 60 and 58, and 61 and 59 are located relative to each other so that the water heat exchange medium entering the pressure reduction chamber 12 through the lower inlet ports 60 and 61 is turned through an angle of 180° to exit through the respective upper outlet ports 58 and 59. This, thus, further increases the turbulence in the water heat exchange medium within the pressure reduction chamber 12.

The turbulence induced in the pressure reduction chamber 12 as well as enhancing the release of dissolved air and dissolved oxygen from the water heat exchange medium, also facilitates in mixing of the water heat exchange medium from the first and second heat exchange circuits 4 and 5 with the water heat exchange medium flowing into the pressure reduction chamber 12 from the heat source circuit 3.

In this embodiment of the invention the inner diameter of the cylindrical side wall 30 is approximately 226mm, while the average internal height of the pressure reduction chamber 12 is approximately 370mm, thus providing the pressure reduction chamber 12 with a volume of 17 litres, approximately. The device 1 with the pressure reduction chamber 12 of volume 17 litres is suitable for use in a heat exchange system of heat output up to 150,000 BTU, and may be suitable for heat exchange systems of significantly higher heat output. It has been found that use of the device 1 of volume of the pressure reduction chamber 12 of 17 litres in a heat exchange system of heat output up to 150,000 BTU allows the water heat exchange medium a dwell time in the pressure reduction chamber 12 sufficient to facilitate release and venting of dissolved gases, and in particular, dissolved air and oxygen from the water heat exchange medium as it passes through the pressure reduction chamber 12.

Released dissolved gases which are not vented through the upper inlet port 54 are re-dissolved into the water heat exchange medium and are released on the next pass of the water heat exchange medium through the pressure reduction chamber 12.

The volume of the pressure reduction chamber 12 is also selected to ensure adequate mixing of the water heat exchange medium from the first and second heat exchange circuits 4 and 5 with the water heat exchange medium from the heat source circuit 3. It has been found that the device 1 with the pressure reduction chamber 12 of volume 17 litres is adequate for providing the appropriate degree of mixing of the water heat exchange medium from the first and second heat exchange circuits 4 and 5 with that of the heat source circuit 3, in a heat exchange system of heat output up to 17 litres.

The operation of the device 10 is based on the principle that dissolved gases are released from a liquid, for example, water when the pressure of the water is reduced at constant temperature, the volume and dimensions of the pressure reduction chamber 12 of the device 10 are selected so that the respective inlet ports 54, 60 and 61 are located in walls, namely, the top wall 32 in the case of the upper inlet port 54 and the side wall 30 in the case of the lower inlet ports 60 and 61 so that the water heat exchange medium flowing into the pressure reduction chamber 12 through the respective inlet ports 54, 60 and 61 is presented with a sudden step change increase in transverse cross-sectional area, which is sufficient for reducing the pressure of the water heat exchange medium as it flows into the pressure 006

29

reduction chamber 12. This reduction in pressure of the water heat exchange medium as it flows into the pressure reduction chamber 12 causes dissolved gases, and in particular, dissolved air and oxygen from the water heat exchange medium to be released. The released gases bubble out of the water heat exchange medium and are vented through the upper inlet port 54 to the header tank 25 from which they are exhausted to atmosphere.

In use, with the boiler 6 and the primary circulating pump 18 operational, the heat exchange system 1 is ready for heating both domestic water in the indirect hot water tank 20 and the radiators in the first and second heat exchange circuits 4 and 5. Depending on the zones of the house to be heated, the appropriate secondary circulating pump 19 or pumps 19 in the first and second heat exchange circuits 4 and 5 are operated for circulating water heat exchange medium from the pressure reduction chamber 12 to the radiators 7. The heated water heat exchange medium circulating between the heat source circuit 3 and the pressure reduction chamber 12 heats the domestic hot water in the indirect hot water tank 20, and in turn mixes with the water heat exchange medium from the first and second heat exchange circuits 4 and 5, the circulating pumps 19 of which are operational, and thus heated water heat exchange medium is circulated through the upper outlet ports 58 and 59 to the flow pipes 16 of the first and second heat exchange circuits 4 and 5, and cooler water heat exchange medium from the radiators 7 is returned through the lower inlet ports 60 and 61 from the return pipes 17 of the first and second heat exchange circuits 4 and 5. The cooler return water heat exchange medium from the first and second heat exchange circuits 4 and 5 is thus returned from the pressure reduction chamber 12 through the return pipe 15 of the heat source circuit 3 to the boiler 6 for reheating. As the flow water heat exchange medium from the heat source circuit 3 and the return water heat exchange medium from the first and second heat exchange circuits 4 and 5 is returned to the pressure reduction chamber 12, dissolved gases, in particular, dissolved air and oxygen are released from the water heat exchange medium as it enters the pressure reduction chamber 12 through the upper inlet port 54 and the lower inlet ports 60 and 61 as already described. The released dissolved air and oxygen bubble through the water heat exchange medium in the pressure reduction chamber 12 and are vented through the upper inlet port 54 and in turn through the water in the header tank 25 to atmosphere.

It has been found that provided there are no leaks in the heat exchange system 1 , top-up water from the header tank 25 should not be required, and in which case, it has been found that after the heat exchange system 1 has been operating for an appropriate number of hours, typically, fifteen to twenty-four hours, substantially all the dissolved gases and oxygen in the water heat exchange medium are removed. Thereafter, use of the heat exchange system continues with the water heat exchange medium with no dissolved gases, air or oxygen in the water heat exchange medium, or if there is any remaining dissolved gases, air or oxygen in the water heat exchange medium, this is subsequently removed by further passes of the water heat exchange medium through the pressure reduction chamber 12.

Referring now to Fig. 12, there is illustrated a heat exchange system also according to the invention indicated generally by the reference numeral 70. The heat exchange system 70 is substantially similar to the heat exchange system 1 and similar components are identified by the same reference numerals. The only difference between the heat exchange system 70 and the heat exchange system 1 is that the heating coil 22 of the indirect hot water tank 20 and flow pipe 14 of the heat source circuit 3 are parallel to each other, and the heat exchange system 70 comprises only one heat exchange circuit, namely, the first heat exchange circuit 4. The second heat exchange circuit has been omitted. Because the second heat exchange circuit has been omitted, the upper outlet port 59 and the lower inlet port 61 are closed off by suitable blanking plugs. Otherwise, the heat exchange system 70 is similar to the heat exchange system 1 and its use and operation is likewise similar.

Referring now to Fig. 13, there is illustrated a heat exchange system 75 which is similar to the heat exchange systems 1 and 70, and similar components are identified by the same reference numerals. In this case the heating coil 22 of the indirect hot water tank 20 is in series with the flow pipe 14 of the heat source circuit 3. The main difference between the heat exchange system 75 and the heat exchange systems 70 and 1 is that the pipework from the upper inlet port 54 of the device 10 does not continuously rise to the header tank 25. Accordingly, in this embodiment of the invention an automatic air vent unit 76 is located in the flow pipe 14 of the heat source circuit 3 adjacent the upper inlet port 54 for venting released dissolved gases from the water heat exchange medium to atmosphere.

Referring now to Fig. 14, there is illustrated a heat exchange system also according to the invention, indicated generally by the reference numeral 80. The heat exchange system 80 is substantially similar to the heat exchange systems 1 and 70 and similar components are identified by the same reference numerals. The heat exchange system 80 comprises only a first heat exchange circuit 4, however, in this embodiment of the invention the heat exchange system 80 is a pressurised closed system which is pressurised by a pressure vessel 81 of the type which will be well known to those skilled in the art. Because of the fact that the heat exchange system 80 is a pressurised closed system, it does not require a header tank 25, and accordingly, an automatic venting unit 82, which is similar to the automatic air vent unit 76 of the heat exchange system 75, is provided in the flow pipe 14 of the heat source circuit 3 adjacent the upper inlet port 54 to the pressure reduction chamber 12. A safety pressure relief valve 83 is also provided in the flow line 14 of the heat source circuit 3 adjacent the boiler 6.

Referring now to Figs. 15 to 19, there is illustrated a heat exchange system according to another embodiment of the invention, indicated generally by the reference numeral 85. The heat exchange system 85 is substantially similar to the heat exchange system 1 and similar components are identified by the same reference numerals. However, in this embodiment of the invention the device 10 is substituted with a device 86 according to another embodiment of the invention also for removing dissolved air and oxygen from the water heat exchange medium.

Referring now in particular to Figs. 16 to 19, the device 86 comprises a housing in the form of a hollow cube comprising a front end wall 87 and a spaced apart rear end wall 88, which are joined by respective spaced apart side walls 89 and 90. A top wall 91 extends between the front and rear end walls 87 and 88 and between the side walls 89 and 90, while a bottom wall 92 extends between the front and rear end walls 87 and 88 and the side walls 89 and 90, and defines with the top wall 91 , the front and rear end walls 87 and 88 and the side walls 89 and 90 a pressure reduction chamber 93. The respective front and rear end walls, side walls and top and bottom walls 87 to 92 are all planar walls and are of similar square shape to form a cube, which in turn defines the pressure reduction chamber 93 as a cubic chamber.

An upper inlet port 94 is centrally located in the top wall 91 for connecfing to the flow pipe 14 of the heat source circuit 3 for accommodating water heat exchange medium from the heat source circuit 3 into the pressure reduction chamber 93. A lower outlet port 95 in the side wall 89 for connecfing to the return pipe 15 of the heat source circuit 3 returns water heat exchange medium from the pressure reduction chamber 93 to the heat source circuit 3, and in turn to the boiler 6. A venting means in this embodiment of the invention is provided by a vent port 97 which is located in the top wall 91 for venting released dissolved gases from the water heat exchange medium. The vent port 97 is connected directly to the supply pipe 26. Although it will be appreciated that the vent port 97 instead of being connected to the supply pipe 26 may be connected to the expansion pipe 28, and the supply pipe 26 would then be connected into the heat exchange system 1 at a suitable alternative location. The vent port 97 is located in the top wall 91 on a diagonal extending through the centre of the top wall 91 to the corner defined by the front end wall 87 and the side wall 89.

In this embodiment of the invention the device 86 also comprises a lower inlet port 98 and an upper outlet port 99 in the front end wall 87 for connecting respectively to the return pipe 17 and flow pipe 16 of the first heat exchange circuit 4. However, in this embodiment of the invention the first heat exchange circuit 4 is omitted, as is the second heat exchange circuit. Accordingly, in this embodiment of the invention the inlet and outlet ports 98 and 99 are not used, and thus are closed off by appropriate blanking plugs. The principle of operation of the device 86 for reducing dissolved gases in the water heat exchange medium is similar to that of the device 10. In order to utilise the principle on which the invention is based, the volume of the pressure reduction chamber 93 is selected and the respective inlet ports 94 and 98 are located in their respective corresponding walls 91 and 87 so that the water heat exchange medium flowing through the inlet ports 94 and 98 into the pressure reducfion chamber 93 is presented with a sudden step change increase in transverse cross-sectional area sufficient for reducing the pressure of the water heat exchange medium as it flows into the pressure reduction chamber 93. This thus releases dissolved gases, and in particular, dissolved oxygen from the water heat exchange medium. The released gases bubble out of the water heat exchange medium to the vent port 97 and in turn rise through the supply pipe 26 into the header tank 25.

Additionally, the volume of the pressure reducfion chamber 93 is such as to induce turbulence in the water heat exchange medium as it is flowing into the pressure reduction chamber 93 through the inlet ports 94 and 98 for further enhancing the release of dissolved gases including oxygen in the water heat exchange medium. The volume of the pressure reduction chamber 93 is also sized to provide a sufficient dwell time for the water heat exchange medium in the pressure reduction chamber 93 to ensure that at least most, if not all of the released gases exit through the vent port 97. Additionally, where the device 86 is utilised for connecting a number of heat exchange circuits to a heat source circuit, the volume of the pressure reduction chamber 93 should be sufficient for facilitating adequate mixing of the water heat exchange medium from the respective heat exchange circuits with the heat source circuit 3.

In order to provide an adequate sudden step change in the transverse cross- sectional area presented to the heat exchange medium as it flows from the inlet ports 94 and 98 into the pressure reducfion chamber 93, it has been found that it is essential that the peripheral edges of the respective inlet ports 94 and 98 should be spaced apart from their adjacent walls 87 to 92 to which they are closest a minimum distance of at least 10mm, measured from the peripheral edges of the respective inlet ports 94, 98 to the inner surface of the closest wall 87 to 92. Additionally, where respective lower inlet and upper outlet ports are located in the same wall 87 to 92, as is the case with the lower inlet and upper outlet ports 98 and 99 in the front end wall 87, it is essential that the minimum spacing of adjacent lower inlet and upper outlet ports 98 and 99 between the adjacent peripheral edges of the respective lower inlet and upper outlet ports 98 and 99 should be at least 15mm. Furthermore, where as will be described below with reference to Figs. 21 and 22 a number of lower inlet ports 98, and a number of upper outlet ports 99 are provided in the same wall 87, it has been found that it is important that the minimum spacing between adjacent lower inlet ports 98 between the adjacent peripheral edges of the adjacent inlet ports is at least 40mm. In this way, it has been found that an adequate step change in the transverse cross-sectional area presented to the water heat exchange medium as it flows from the inlet ports 94 and 98 into the pressure reduction chamber 93 is sufficient for releasing a reasonable amount of dissolved gases, and in particular, oxygen from the water heat exchange medium.

In this embodiment of the invention the internal volume of the pressure reduction chamber 93 is 22 litres, approximately, being formed by the walls 87 to 92 of inner dimensions 279mm by 279mm. Thus, the centre of the upper inlet port 94 in the top wall 91 is spaced apart from each of the inner surfaces of the front end and side walls 87 to 90 a minimum distance of 139.5mm. The bore diameter of the inlet ports 94 and 98 is 25mm. The bore diameter of the upper outlet ports 99 is also 25mm, while the bore diameter of the lower outlet port 95 is 38mm. The lower inlet port 98 in the front end wall 87 is closest to the bottom wall 92 and the centre of the lower inlet port 98 is spaced apart from the inner surface of the bottom wall 92 a distance of 50mm. The location of the outlet ports 95 and 99 relative to the adjacent walls 87 to 92 is not particularly critical, however, it is desirable that they should be spaced apart at least 50mm from their closest adjacent wall, centre of port to wall.

The housing of the device 86 may be of any suitable material, however, since dissolved oxygen is being released from the water heat exchange medium within the pressure reduction chamber 93 it may in certain circumstances be desirable that the housing should be of a non-corrosive material, such as, for example, stainless steel. However, in general, it has been found that in the device 86 according to the invention dissolved air and oxygen is so rapidly released that a housing of mild steel is adequate. Additionally, since dissolved oxygen and gases are being released from the water heat exchange medium within the pressure reduction chamber 93, the walls 87 to 92 are subjected to fluctuations in pressure, and it is important that the housing should be of sufficient strength to withstand such pressure fluctuations. Typically, walls of 5mm thickness should be adequate.

In use, water heat exchange medium heated in the boiler 6 is circulated by the primary circulating pump 18 through the flow and return pipes 14 and 15, respectively, from the boiler 6 to the heating coil 22 of the indirect hot water tank 20 for transferring heat from the boiler 6 to the indirect hot water tank 20 for heating domestic water therein. The water heat exchange medium from the indirect hot water tank 20 on passing through the upper inlet port 94 into the pressure reduction chamber 93 on being presented with the sudden step change increase in transverse cross-sectional area expands, thus reducing the pressure in the water heat exchange medium, and in turn releasing dissolved gases, and in particular dissolved oxygen from the water heat exchange medium. The dissolved gases and oxygen bubble through the water heat exchange medium in the pressure reduction chamber 93, and exit through the vent port 97. The dissolved gases and oxygen from the vent port 97 are vented through the supply pipe 26, into the header tank 25, and thus to atmosphere. Any released dissolved gases which do not exit through the vent port 97 are redissolved into the water heat exchange medium, for subsequent release on the next pass through the pressure reducfion chamber 93.

Referring now to Fig. 20, there is illustrated a heat exchange system according to another embodiment of the invention indicated generally by the reference numeral 100. The heat exchange system 100 is substanfially similar to the heat exchange system 85 and similar components are identified by the same reference numeral. However, in this embodiment of the invention a first heat exchange circuit 4 is provided, which comprises a plurality of radiators 7, although only one radiator 7 is illustrated. The return pipe 17 of the first heat exchange circuit 4 is connected into the lower inlet port 98 of the device 86, while the flow pipe 16 is connected to the upper outlet port 99 of the device 86. Water heat exchange medium returning through the lower inlet port 98 from the return pipe 17 into the pressure reduction chamber 93 is presented with a sudden step change increase in transverse cross- sectional area, thus reducing the pressure of the returning water heat exchange medium, which results in release of dissolved gases, and in particular oxygen from the water heat exchange medium. As already described with reference to the heat exchange systems 1 and 85, the released gases and oxygen bubble through the water heat exchange medium in the pressure reducfion chamber 93 and exit through the vent port 97 to the header tank 25.

The returning water heat exchange medium from the first heat exchange circuit 4 is mixed with hot water heat exchange medium from the heat source circuit 3 from the boiler 6, and is thus heated for recirculation from the device 86 into the first heat exchange circuit 4. The rise in temperature of the water heat exchange medium returning from the first heat exchange circuit 4 further enhances the release of dissolved gases including dissolved oxygen from the returning water heat exchange medium.

In this embodiment of the invention water heat exchange medium flowing into the pressure reducfion chamber 93 from the heat source circuit 3 through the upper inlet port 94, and from the first heat exchange circuit 4 through the lower inlet port 98 is subjected to a reducfion in pressure, thus releasing dissolved gases including dissolved oxygen from the water heat exchange medium, which in turn exits through the vent port 97.

Otherwise, operation of the heat exchange system 100 is substantially similar to that of the heat exchange systems 1 and 85.

Referring now to Fig. 21 , there is illustrated a device 110 according to another embodiment of the invention also for removing dissolved gases and in particular dissolved oxygen from water heat exchange medium in a central heat exchange system. The device 110 is substanfially similar to the device 86, and similar components are identified by the same reference numerals. The only difference between the device 110 and the device 86 is that two lower inlet ports 98a and 98b and two upper outlet ports 99a and 99b are provided in the front end wall 87 of the device 110. The bore diameters of the inlet and outlet ports are similar to the bore diameters of the corresponding inlet and outlet ports of the device 86. The spacing between the centres of the respective lower inlet ports 98a and 98b and their closest adjacent wall 87 to 92, and the spacing between the centres of the respective upper outlet ports 99a and 99b and their closest adjacent walls 88 to 92 is similar to that already described with reference to the device 86. Additionally, the spacing between the centres of the lower inlet ports 98a and 98b is approximately 140mm, and the spacing between the centres of the lower inlet ports 98a and 98b and their closest upper outlet port 99a and 99b is approximately 179mm. Otherwise the device 110 is similar to the device 86.

In general, it is envisaged that a heat source circuit will be connected to the device 110 through the upper inlet and lower outlet ports 94 and 95, and respective heat exchange circuits will be connected to the device 110 through the respective lower inlet and upper outlet ports 98a, 98b and 99a and 99b. Although, it will be appreciated that a second heat source circuit may be connected through one of the pairs of lower inlet and upper outlet ports 98a, 98b and 99a and 99b. In which case, the upper outlet port 99 would become an inlet port for connecting to the flow pipe of the heat source circuit, and the lower inlet port 98 would become an outlet port for connecfing to the return pipe of the heat source circuit.

Referring now to Fig. 22, there is illustrated a device 115 also according to the invention for removing dissolved gases including dissolved oxygen in a water heat exchange medium of a heat exchange system. The device 115 is substantially similar to the devices 86 and 110, and similar components are identified by the same reference numerals. The only difference between the device 115 and the devices 86 and 110 is that three pairs of lower inlet and upper outlet ports 98 and 99 are provided in the front end wall 87, which lower inlet and upper outlet ports are identified by the reference numerals 98a, 98b and 98c, and 99a, 99b and 99c, respectively. It is envisaged that a heat source circuit will be connected to the upper inlet and lower outlet ports 94 and 95 of the device 115, while respecfive heat exchange circuits will be connected to the respecfive pairs of lower inlet and upper outlet ports 98a, 98b and 98c, and 99a, 99b and 99c. Alternatively, a second and/or third heat source circuit could be connected to the device 115 through any of the pairs of lower inlet and upper outlet ports 98a, 98b and 98c, and 99a, 99b and 99c, respectively.

In this embodiment of the invention the spacing between adjacent lower inlet ports 98, centre to centre is approximately 65mm, while the spacing between adjacent lower inlet and upper outlet ports 98 and 99 is approximately 179mm.

Otherwise, the device 115 is similar to the devices 86 and 110, and its operation is likewise similar.

Referring now to Fig. 23, there is illustrated a heat exchange system 120 according to a further embodiment of the invention, which is also substantially similar to the heat exchange system 85, and similar components are identified by the same reference numerals. In this embodiment of the invention the heat exchange system 120 is a closed system, and the boiler 6 is an oil or gas fired boiler. The heat exchange system 120 comprises two devices for removing dissolved gases from water heat exchange medium, namely, a device 86 and a device 110. The device 86 connects the heat source circuit 3 to an intermediate circuit 121 which includes a flow pipe 122 and a return pipe 123. The intermediate circuit 121 supplies water heat exchange medium from the device 86 to the device 110 which in turn supplies the water heat exchange medium to a heat exchange circuit 125. The heat exchange circuit 125 comprises a plurality of heat exchangers, in this embodiment of the invention provided by under floor heat exchange units 126.

The device 86 is connected to the heat source circuit 3 in similar fashion as the device 86 is connected into the heat exchange system 85, the flow pipe 14 from the heat source circuit 3 being connected to the upper inlet port 94 in the top wall 91 of the device 86 and the return pipe 15 to the boiler 6 being connected to the lower outlet port 95 in the side wall 89. The flow pipe 122 of the intermediate circuit 121 is connected to the upper outlet port 99 of the device 86, while the return pipe 123 of the intermediate circuit 121 is connected to the lower inlet port 98 of the device 86. A pressure vessel 127 is connected to the vent port 97 of the device 86 for pressurising the heat exchange system 120. An automatic vent valve 128 located between the device 86 and the pressure vessel 127 and adjacent the vent port 97 vents released dissolved gases from the pressure reduction chamber 93 of the device 86. Otherwise operation of the device 86 is substanfially similar to the operation of the device 86 described with reference to the heat exchange system 85.

A mixing valve 130 is located in the flow pipe 122 of the intermediate circuit 121 and is connected to the return pipe 123 by an intermediate pipe 131 for mixing return water heat exchange medium from the device 110 with flow water heat exchange medium from the device 86 for controlling the temperature of the water heat exchange medium to the device 110. The operation of such mixing valves will be well known to those skilled in the art. A secondary circulating pump 133 located in the flow pipe 122 of the intermediate circuit 121 circulates water heat exchange medium between the respective devices 86 and 110.

The heat exchange circuit 125 comprises a flow pipe 135 and a return pipe 136. A secondary circulating pump 137 in the flow pipe 135 circulates water heat exchange medium through the heat exchange circuit 125 between the device 110 and the under floor heat exchange units 126.

In this embodiment of the invention only the lower inlet ports 98a and 98b and the upper oufiet ports 99a and 99b of the device 110 are used. The flow pipe 122 of the intermediate circuit 121 is connected to the upper outlet port 99a, which acts as an inlet port to the pressure reducfion chamber 93, while the return pipe 123 of the intermediate circuit 121 is connected to the lower inlet port 98a, which acts as an outlet port to the pressure reducfion chamber 93. The flow pipe 135 of the heat exchange circuit 125 is connected to the upper outlet port 99b of the device 110, while the return pipe 136 of the heat exchange circuit 125 is connected to the lower inlet port 98b of the device 110. An automafic vent valve 138 is connected to the vent port 97 of the device 110 for venting released dissolved gases from the pressure reduction chamber 93 of the device 110.

In use, operation of the device 86 with respect to the heat source circuit 3 and the intermediate circuit 121 is similar to the operation of the device 86 in the heat exchange system 85. Return water heat exchange medium being returned to the device 86 through the return pipe 123 of the intermediate circuit 121 is presented with a sudden step change increase in transverse cross-sectional area as it enters the pressure reduction chamber 93 of the device 86, and thus expands reducing the pressure of the water heat exchange medium. Dissolved gases and dissolved oxygen in the water heat exchange medium are released from the water heat exchange medium and vented through the vent port 97, and in turn through the automatic vent valve 128. Flow water heat exchange medium to the device 86 through the flow pipe 14 of the heat source circuit 3 is also presented with a sudden step change increase in the transverse cross-sectional area as it enters the pressure reduction chamber 93 through the upper inlet port 94, and thus expands also releasing dissolved gases from the water heat exchange medium, which are in turn vented through the vent port 97.

Return water heat exchange medium to the device 110 from the return pipe 136 of the heat exchange circuit 125 is likewise presented with a sudden step change increase in transverse cross-sectional area as it enters the pressure reduction chamber 93 through the lower inlet port 98b, and thus expands reducing the pressure in the water heat exchange medium, and thus releasing dissolved gases and oxygen therefrom, which are in turn vented through the vent port 97, and in turn the automafic vent valve 138. Additionally, flow water heat exchange medium in the flow pipe 122 of the intermediate circuit 121 similarly is subjected to a reducfion in pressure as it enters the pressure reducfion chamber 93 of the device 110 through the upper outlet port 99a, thus releasing dissolved gases, which are in turn vented through the vent port 97 and the automatic vent valve 138.

While the heat exchange systems of Figs. 15, 20 and 23 have been described as comprising devices 86 and 110 which are of cubic shape, the devices 86 and 110 may be replaced by the device 10. Additionally, the device 10 in the heat exchange systems of Figs. 1 , 12, 13 and 14 may be replaced with the devices 86, 110 or 115.

While the devices 86 and 110 have been described as comprising upper outlet ports and lower inlet ports on the same side wall, each side wall may be provided with one pair or more than one pair of lower inlet and upper outlet ports.

It will also be appreciated that more than one lower outlet port may be provided from the devices 86 and 110 for connecfing the devices 86 and 110 with more than one heat source circuit, and indeed, the lower outlet ports may be provided on the same or different side walls, and furthermore, such lower outlet ports could be provided in the front and rear end walls also if desired, as well as in the side walls.

While the device 10 has been described as comprising two lower inlet ports and two upper outlet ports, it will be readily apparent to those skilled in the art that the device 10 may be provided with many more pairs of lower inlet and upper outlet ports. Similarly, more than two lower outlet ports may be provided for connecting the device 10 with a corresponding number of heat source circuits.

While the devices 10, 86, 110 and 115 have been described as being of a specific volume, it will be readily apparent to those skilled in the art that the devices may be provided of different volumes, and indeed, the devices would be provided in appropriate volumes to match the capacity of the heat exchange systems into which they are to be connected.

It will also be appreciated that while the device 10 has been described as comprising only a single turbulence inducing rib, the device may be provided with a number of turbulence inducing ribs, and this would particularly be so where the device is provided with more than two lower inlet ports. In general, it is envisaged that a turbulence inducing rib will be provided between each adjacent pair of lower inlet ports.

It will also be appreciated that while the turbulence inducing means has been described in the device 10 as being provided by a turbulence inducing rib, any other suitable turbulence inducing means may be provided. It is also envisaged that while the adjacent side walls to the side wall in which an inlet port is provided to the devices 86, 110 and 115 are adequate for inducing an appropriate degree of turbulence into the water heat exchange medium in the pressure reducfion chamber of the devices, additional turbulence inducing means may be provided, for example, turbulence inducing ribs similar to that provided in the device 10.

An advantage of providing the vent port 97 between the upper inlet port 94 and the corner defined by the front end wall 87 and the side wall 89 in which the lower inlet and upper outlet ports 98 and 99, and the outlet port 95, respectively are located is that the volume beneath the vent port 97 is the volume within the pressure reduction chamber 93 in which most turbulence occurs, and thus the volume in which the maximum amount of dissolved air and oxygen is released from the water heat exchange medium. This is due to the fact that the lower inlet and upper outlet ports 98 and 99 are located in the front end wall 28 and the lower outlet port 95 is located in the side wall 89, and the fact that the water heat exchange medium from the heat exchange circuit is turned through 90° as it passes through the pressure reducfion chamber 93, and the water heat exchange medium from the heat exchange circuits 4 and 5 is turned through 180° as it passes through the pressure reducfion chamber 93. Thus, the released dissolved air and oxygen is rapidly vented from the pressure reducfion chamber 93.

It has been found that by releasing all or as much of the dissolved gases and oxygen in the water heat exchange medium by use of the device according to the invention the efficiency of a heat exchange system incorporating the device is significantly increased, and the significant increase in efficiency has been found to lead to significant reductions in fuel consumption of a heat exchange system. Tests on the same heat exchange system before the device according to the invention was installed and after the device was installed have demonstrated that fuel consumption can be reduced by a minimum of 19%, and in certain cases reductions of up to 32.6% in fuel consumpfion can be achieved. By reducing and eliminating dissolved gases and oxygen to the extent that is physically possible from the water heat exchange medium permits the flow rate through the heat exchange system to be increased by a minimum of 21.6%. Furthermore, after a heat exchange system has been operating for approximately 24 hours, sufficient dissolved gases and oxygen are removed from the system to allow operation of the heat exchange system with the temperature of the radiators operating at similar temperatures within a tolerance of 3°.

Additionally, by virtue of the fact that the flow rate of the water heat exchange medium through the heat exchange system is increased by use of the device according to the invention, circulating pump or pumps within the heat exchange system can be set at their lowest settings while still maintaining the desired heat output from the heat exchange system. Indeed, it has been found that after a heat exchange system with the device according to the invention installed had been running for approximately 12 hours, a significant increase in the throughput of water through a swimming pool filtration system was achieved, and the increase achieved was approximately 23.6%.

Furthermore, by virtue of the fact that as much of the dissolved oxygen as is physically possible has been released from the water heat exchange medium, corrosion within the heat exchange system is minimised, and in most cases eliminated, thus avoiding generation of sludge which otherwise inhibits the heat transfer efficiency through the heat exchangers in the heat exchange circuits, and indeed, also inhibits heat transfer into the water heat exchange medium in the boiler or boilers. A further advantage of the device according to the invention is that it is suitable for installation in new heat exchange systems, and is also ideally suited for retrofitting in existing heat exchange systems.

While heat exchange systems with specific heat exchange and heat source circuits have been described to illustrate use of the devices according to the invention, it will be readily apparent to those skilled in the art that the devices according to the invention may be installed in heat exchange systems of other circuit layouts. For example, it is envisaged that the heat source circuit may be provided without the indirect hot water tank located in the flow pipe of the heat source circuit. In which case, it is envisaged that the indirect hot water tank may be provided in one of the heat exchange circuits, or may be provided in a separate independent heat exchange circuit connected to the device through a pair of lower inlet and upper outlet ports.

It is also envisaged that one or more of the lower inlet ports and one or more of the upper outlet ports may be located in the base wall of the devices.

While the housing of the device 10 has been described as being of plasfics material and formed in two parts, it is envisaged that the housing 10 may be of any other suitable material, for example, metal, such as stainless steel, mild steel or the like, as well as copper, brass or any other suitable metal. Addifionally, while the device 10 has been described as being formed as a two part housing, the housing may be formed in one piece, and where the housing is formed by, for example, rotational plasfics moulding, the housing typically would be formed as a one piece housing. Where the housing is of metal material or other such heat conductive materials, the housing may be encased or surrounded by a suitable heat insulating material, and indeed, even where the housing of the device is provided in a plastics material, the housing may also be surrounded or encased in a suitable heat insulating material.

While the devices 86, 110 and 115 have been described as being of cubic shape, the devices may be of any other suitable or desired parallelepiped shape, or indeed, 006

45

any other suitable or desired shape. It is also envisaged that the device 10 may be of other suitable shape besides that described, for example, instead of the side wall being a cylindrical side wall, it could be a multi-panel side wall, for example, a multi- panel side wall which would define a hexagonal, octagonal or the like cross-section in plan view. It will also be appreciated that while the devices have been described as comprising inlet and oufiet ports of specific diameters, the inlet and outlet ports may be of any other suitable cross-section, circular or otherwise, and may be of any other suitable or desired dimensions. Needless to say, while specific posifionings of inlet and outlet ports relative to each other, and relafive to side and end walls have been described, other suitable posifionings of the inlet and outlet ports may be adopted. Indeed, it is envisaged that the housing of the respecfive devices, as well as the inlet and outlet ports, and the respective locations of the inlet and outlet ports relative to each other and relative to side and end walls, may be scaled upwardly or downwardly, while still achieving desirable results.

It is also envisaged that while the size of the housings may be scaled upwardly or downwardly, and while the distances of the inlet and outlet ports from their closest walls and their positioning relafive to each other may also be scaled in certain cases, it is envisaged that the port sizes may not necessarily be correspondingly scaled.

Claims

1. A device for removing dissolved gases in a liquid heat exchange medium of a heat exchange system of the type comprising a heat source and a heat exchanger, the liquid heat exchange medium being circulated between the heat source and the heat exchanger for transferring heat from the heat source to the heat exchanger, characterised in that the device comprises a housing defining a pressure reduction chamber for accommodating the liquid heat exchange medium therethrough, at least one inlet port for connecting the device into the heat exchange system and for accommodating the liquid heat exchange medium into the pressure reduction chamber from the heat exchange system, at least one outlet port for connecfing the device into the heat exchange system for returning the liquid heat exchange medium from the pressure reduction chamber to the heat exchange system, the pressure reducfion chamber providing a sudden step change increase in the transverse cross- sectional area presented to the heat exchange medium between the inlet port and the outlet port sufficient for reducing the pressure in the liquid heat exchange medium flowing through the pressure reducfion chamber for releasing dissolved gases from the heat exchange medium, and a venting means from the pressure reducfion chamber for venting gases released from the heat exchange medium.

2. A device as claimed in Claim 1 characterised in that the volume of the pressure reducfion chamber is such as to facilitate the release of dissolved gases from the liquid heat exchange medium.

3. A device as claimed in Claim 1 or 2 characterised in that the volume of the pressure reducfion chamber is such as to allow sufficient dwell time to the liquid heat exchange medium therein for at least some of the dissolved gases released from the heat exchange medium to exit through the venting means.

4. A device as claimed in any preceding claim characterised in that the step change in the transverse cross-sectional area presented to the liquid heat exchange medium between the inlet port and the outlet port is sufficient for inducing turbulence in the heat exchange medium for further facilitating release of dissolved gases from the heat exchange medium in the pressure reduction chamber.

5. A device as claimed in any preceding claim characterised in that the housing comprises a side wall.

6. A device as claimed in Claim 5 characterised in that a turbulence inducing means is located in the pressure reducfion chamber for inducing turbulence in the liquid heat exchange medium in the pressure reducfion chamber for further facilitating the release of dissolved gases from the heat exchange medium.

7. A device as claimed in Claim 6 characterised in that the turbulence inducing means is located spaced apart from at least one of the at least one inlet port.

8. A device as claimed in Claim 6 or 7 characterised in that the turbulence inducing means extends into the pressure reducfion chamber from the housing, and is located spaced apart from at least one of the at least one inlet port.

9. A device as claimed in any of Claims 6 to 8 characterised in that the turbulence inducing means comprises an elongated turbulence inducing rib extending longitudinally along the side wall.

10. A device as claimed in Claim 8 or 9 characterised in that the turbulence inducing means extends from the side wall into the pressure reduction chamber a distance between 1mm and 5mm.

11. A device as claimed in any of Claims 8 to 10 characterised in that the turbulence inducing means is of width in the range of 2mm to 4mm.

12. A device as claimed in any of Claims 6 to 11 characterised in that one of the at least one inlet ports is located in the side wall, and the turbulence inducing means extends from the side wall spaced apart from the inlet port located in the side wall. 49

turbulence inducing means to the centre of the inlet port for a distance corresponding to at least two diameters of the inlet port.

20. A device as claimed in Claim 19 characterised in that the turbulence inducing means extends on the first side of the line extending perpendicularly from the turbulence inducing means to the centre of the inlet port for a distance corresponding to at least three diameters of the inlet port.

21. A device as claimed in any of Claims 17 to 20 characterised in that the turbulence inducing means extends on the second side of the line extending perpendicularly from the turbulence inducing means to the centre of the inlet port for a distance corresponding to at least two diameters of the inlet port.

22. A device as claimed in any of Claims 12 to 21 characterised in that a pair of inlet ports are located in the side wall, and the turbulence inducing means is located between the respective inlet ports.

23. A device as claimed in Claim 22 characterised in that the turbulence inducing means extends perpendicularly to a line joining the centres of the two inlet ports.

24. A device as claimed in Claim 22 or 23 characterised in that the turbulence inducing means is located equi-spaced between the two inlet ports.

25. A device as claimed in any of Claims 12 to 24 characterised in that the side wall is a cylindrical side wall, and the turbulence inducing means extends in a generally axial direction relafive to the cylindrical side wall.

26. A device as claimed in Claim 25 characterised in that the cylindrical side wall defines a geometrical longitudinally extending central axis.

27. A device as claimed in Claim 26 characterised in that the device is adapted for connecting into the heat exchange system with the central axis extending 48

13. A device as claimed in Claim 12 characterised in that the turbulence inducing means is located relative to the inlet port so that the perpendicular distance from the turbulence inducing means to the centre of the inlet port lies in the range of one times the diameter of the inlet port to three. times the diameter of the inlet port.

14. A device as claimed in Claim 12 or 13 characterised in that the turbulence inducing means is located relafive to the inlet port so that the perpendicular distance from the turbulence inducing means to the centre of the inlet port is approximately twice the diameter of the inlet port.

15. A device as claimed in any of Claims 12 to 14 characterised in that the turbulence inducing means extends along the side wall for a distance corresponding to at least the diameter of the inlet port.

16. A device as claimed in any of Claims 12 to 15 characterised in that the turbulence inducing means extends along the side wall for a distance corresponding to at least three times the diameter of the inlet port.

17. A device as claimed in any of Claims 12 to 16 characterised in that the turbulence inducing means extends from a line extending perpendicularly from the tubular inducing means to the centre of the inlet port on opposite first and second sides of the said line a distance corresponding to at least one and a half diameters of the inlet port.

18. A device as claimed in Claim 17 characterised in that the turbulence inducing means extends for a distance from the first side of the said line extending perpendicularly from the turbulence inducing means to the centre of the inlet port a distance greater than the distance from which the turbulence inducing means extends from the second side of the said line.

19. A device as claimed in Claim 18 characterised in that the turbulence inducing means extends on the first side of the line extending perpendicularly from the substantially vertically.

28. A device as claimed in any preceding claim characterised in that the housing comprises a top wall and a spaced apart bottom wall, the top and bottom walls extending transversely of the side wall, and the side wall extends between the top and bottom walls.

29. A device as claimed in Claim 28 characterised in that each inlet port located in the side wall of the housing is located in the side wall towards the bottom wall thereof.

30. A device as claimed in Claim 28 or 29 characterised in that an inlet port is located in the top wall.

31. A device as claimed in any of Claims 28 to 30 characterised in that the top wall is of dome shape, and the inlet port is located substantially centrally in the top wall.

32. A device as claimed in any of Claims 28 to 31 characterised in that the venting means is located in the top wall.

33. A device as claimed in any of Claims 30 to 32 characterised in that the inlet port in the top wall acts as the venting means.

34. A device as claimed in any of Claims 30 to 33 characterised in that an outlet port is located in the side wall co-operating with the inlet port in the top wall for connecting the device into a heat exchange system.

35. A device as claimed in Claim 34 characterised in that the oufiet port which co-operates with the inlet port in the top wall is located towards the bottom wall.

36. A device as claimed in any of Claims 12 to 35 characterised in that an outlet port is located in the side wall corresponding to each inlet port in the side wall for cooperating with the said corresponding inlet port for connecfing the device into the central heat exchange system.

37. A device as claimed in Claim 36 characterised in that each outlet port in the side wall corresponding to an inlet port in the side wall is located spaced apart from and at a level above the corresponding inlet port.

38. A device as claimed in any of Claims 5 to 37 characterised in that the side wall adjacent each inlet port extends substantially transversely of the direction of flow of heat exchange medium from the inlet port into the pressure reducfion chamber.

39. A device as claimed in any of Claims 5 to 38 characterised in that the side wall of the housing comprises at least one planar side wall.

40. A device as claimed in Claim 39 characterised in that the turbulence inducing means comprises an adjacent wall extending from the planar side wall.

41. A device as claimed in Claim 40 characterised in that two of the walls extending from the planar side wall form side walls of the housing.

42. A device as claimed in Claim 40 or 41 characterised in that each side wall is a planar side wall.

43. A device as claimed in any of Claims 40 to 42 characterised in that each side wall extending from a planar side wall extends from the planar side wall at a location spaced apart from an adjacent one of the inlet ports a sufficient distance for providing the sudden step change in the transverse cross-sectional area presented to the heat exchange medium.

44. A device as claimed in any of Claims 40 to 42 characterised in that the periphery of each inlet port is spaced apart from the side wall to which it is closest a distance of at least 10mm.

45. A device as claimed in any of Claims 40 to 44 characterised in that the periphery of each inlet port is spaced apart from the side wall to which it is closest a distance of at least 12.5mm.

46. A device as claimed in any of Claims 40 to 45 characterised in that the periphery of each inlet port is spaced apart from the side wall to which it is closest a distance of at least 15mm.

47. A device as claimed in any of Claims 40 to 46 characterised in that the periphery of each inlet port is spaced apart from the side wall to which it is closest a distance of at least 25mm.

48. A device as claimed in any of Claims 40 to 47 characterised in that each inlet port is of diameter approximately 25mm, and each inlet port is spaced apart from the side wall to which it is closest a distance, centre to side wall of at least 45mm.

49. A device as claimed in any of Claims 40 to 48 characterised in that each inlet port is of diameter approximately 25mm, and each inlet port is spaced apart from the side wall to which it is closest a distance, centre to side wall of at least 50mm.

50. A device as claimed in any of Claims 40 to 49 characterised in that each inlet port is of diameter approximately 25mm, and each inlet port is spaced apart from the side wall to which it is closest a distance, centre to side wall of at least 60mm.

51. A device as claimed in any of Claims 40 to 50 characterised in that each inlet port is of diameter approximately 25mm, and each inlet port is spaced apart from the side wall to which it is closest a distance, centre to side wall of at least 70mm.

52. A device as claimed in any of Claims 39 to 51 characterised in that the housing is a six-sided housing having six planar walls defining six inner planar wall surfaces forming the pressure reducfion chamber.

53. A device as claimed in Claim 52 characterised in that the pressure reducfion chamber is parallelepiped.

54. A device as claimed in Claim 51 or 52 characterised in that the pressure reducfion chamber is cubic.

55. A device as claimed in any of Claims 39 to 54 characterised in that at least one inlet port and one outlet port are provided in the same planar wall of the housing.

56. A device as claimed in any preceding claim characterised in that the minimum distance between peripheral edges of adjacent inlet and outlet ports in the same wall is at least 154mm.

57. A device as claimed in any preceding claim characterised in that the minimum distance between peripheral edges of adjacent inlet and outlet ports in the same wall is at least 164mm.

58. A device as claimed in any preceding claim characterised in that the minimum distance between peripheral edges of adjacent inlet and outlet ports in the same wall is at least 175mm.

59. A device as claimed in any preceding claim characterised in that the minimum distance between the peripheral edges of adjacent inlet ports on the same wall is at least 40mm.

60. A device as claimed in any preceding claim characterised in that the minimum distance between the peripheral edges of adjacent inlet ports on the same wall is at least 75mm.

61. A device as claimed in any preceding claim characterised in that the minimum distance between the peripheral edges of adjacent inlet ports on the same wall is at least 115mm.

62. A device as claimed in any preceding claim characterised in that a plurality of inlet ports are provided to the pressure reduction chamber, and a plurality of outlet ports are provided from the pressure reducfion chamber for connecfing a plurality of circuits of the heat exchange system, at least one of the circuits being a heat source circuit comprising a heat source for heating the liquid heat exchange medium, and at least one of the circuits being a heat exchange circuit comprising a heat exchanger for transferring heat from the liquid heat exchange medium of the heat exchange system.

63. A device as claimed in Claim 62 characterised in that the volume of the pressure reducfion chamber is sufficient for facilitating mixing of the liquid heat exchange medium in the pressure reducfion chamber from respecfive circuits of the heat exchange system.

64. A device as claimed in Claim 62 or 63 characterised in that the volume of the pressure reducfion chamber is sufficient for facilitating mixing of the liquid heat exchange medium in the pressure reduction chamber from each operational heat exchange circuit with the liquid heat exchange medium from each operational heat source circuit.

65. A device as claimed in any of Claims 62 to 64 characterised in that each outlet port for returning the liquid heat exchange medium to a heat source circuit is located relative to the inlet port through which the liquid heat exchange medium is received into the pressure reducfion chamber from the heat source circuit so that the direction of flow of the liquid heat exchange medium from the pressure reducfion chamber is at 90° to the direcfion of flow of the liquid heat exchange medium into the pressure reducfion chamber.

66. A device as claimed in any of Claims 62 to 65 characterised in that the inlet and outlet ports for connecfing the device to each heat exchange circuit are arranged so that the direcfion of flow of the liquid heat exchange medium from the pressure reduction chamber to the heat exchange circuit is at 180° to the direcfion of flow of the liquid heat exchange medium into the pressure reduction chamber from the heat exchange circuit.

67. A device as claimed in any preceding claim characterised in that the liquid heat exchange medium of the heat exchange system is a water heat exchange medium.

68. A device as claimed in preceding claim characterised in that the device is adapted for releasing dissolved oxygen from the liquid water heat exchange medium.

69. A heat exchange system comprising a heat source, and at least one heat exchanger, and a circulating system for circulating a liquid heat exchange medium between the heat source and the heat exchanger, and a device as claimed in any preceding claim for removing dissolved gases from the liquid heat exchange medium, characterised in that the device is connected into the circulating system so that the circulating heat exchange medium circulates through the pressure reduction chamber of the device for reducing the pressure of the liquid heat exchange medium in the pressure reducfion chamber for releasing dissolved gases from the liquid heat exchange medium.

70. A heat exchange system as claimed in Claim 69 characterised in that the heat exchange system comprises at least one heat source circuit, each heat source circuit comprising a heat source for heating the liquid heat exchange medium, and at least one heat exchange circuit, each heat exchange circuit comprising at least one heat exchanger for transferring heat from the liquid heat exchange medium.

71. A heat exchange system as claimed in Claim 70 characterised in that each heat source circuit comprises a flow pipe and a return pipe, the flow pipe of each heat source circuit being connected to the inlet port in the top wall of the housing of the device for delivering heat exchange medium into the pressure reduction chamber, and the return pipe of each heat source circuit being connected to a corresponding one of the outlet ports in the side wall of the housing co-operating with the inlet port in the top wall for returning heat exchange medium to the heat source circuit.

72. A heat exchange system as claimed in Claim 70 or 71 characterised in that each heat exchange circuit comprises a flow pipe and a return pipe, the return pipe of each heat exchange circuit being connected to a corresponding one of the inlet ports in the side wall of the housing of the device for returning heat exchange medium to the pressure reduction chamber, and the flow pipe of each heat exchange circuit being connected to a corresponding one of the outlet ports in the side wall of the housing of the device for receiving heat exchange medium from the pressure reducfion chamber.

73. A heat exchange system as claimed in any of Claims 69 to 72 characterised in that each heat exchanger comprises a heat exchanger for space heating.

74. A heat exchange system as claimed in any of Claims 69 to 73 characterised in that at least one of the heat exchangers comprises a heat exchanger for providing under floor heating.

75. A heat exchange system as claimed in any of Claims 69 to 74 characterised in that at least one of the heat exchangers comprises a heat exchanger for heating water for a swimming pool.

76. A heat exchange system as claimed in any of Claims 69 to 75 characterised in that at least one of the heat exchangers is a heat exchanger for heating domesfic water.

77. A heat exchange system as claimed in any of Claims 69 to 76 characterised in that the circulating system comprises a primary circulating means in each heat source circuit for circulating the liquid heat exchange medium through the heat source circuit between the heat source and the pressure reducfion chamber of the device.

78. A heat exchange system as claimed in any of Claims 69 to 77 characterised in that the circulating system comprises a secondary circulating means in each heat exchange circuit for circulating the liquid heat exchange medium through the heat exchange circuit between the pressure reduction chamber and each heat exchanger in the heat exchange circuit.

79. A method for removing dissolved gases in a liquid heat exchange medium of a heat exchange system of the type which comprises a heat source and a heat exchanger, the liquid heat exchange medium being circulated between the heat source and the heat exchanger for transferring heat from the heat source to the heat exchanger, characterised in that the method comprises the step of passing the liquid heat exchange medium into a pressure reducfion chamber having an inlet port for receiving the liquid heat exchange medium from the heat exchange system and an outlet port for returning the liquid heat exchange medium to the heat exchange system, and the pressure reducfion chamber provides a sudden step change increase in the transverse cross-sectional area presented to the liquid heat exchange medium between the inlet port and the oufiet port for reducing the pressure of the liquid heat exchange medium flowing through the pressure reducfion chamber sufficient for releasing dissolved gases from the liquid heat exchange medium, and venting the dissolved gases from the pressure reducfion chamber.

80. A method as claimed in Claim 79 characterised in that the method comprises the further step of providing the pressure reducfion chamber with a volume such as to facilitate the release of dissolved oxygen from the liquid heat exchange medium.

81. A method as claimed in Claim 79 or 80 characterised in that the volume of the pressure reduction chamber is such as to allow sufficient dwell time for the liquid heat exchange medium therein for venting at least some of the dissolved gases released from the liquid heat exchange medium therefrom.

82. A method as claimed in any of Claims 79 to 81 characterised in that the method further comprises the step of inducing turbulence in the liquid heat exchange medium in the pressure reducfion chamber for further facilitating the release of dissolved gases from the liquid heat exchange medium.

83. A method as claimed in Claim 82 characterised in that a turbulence inducing means is provided in the pressure reducfion chamber for inducing turbulence in the heat exchange medium.

84. A method as claimed in Claim 83 characterised in that the turbulence inducing means is located spaced apart from one of the inlet ports to the pressure reduction chamber.

85. A method as claimed in Claim 83 or 84 characterised in that the turbulence inducing means is provided by an elongated rib extending along a side wall of a housing defining the pressure reduction chamber.

86. A method as claimed in any of Claims 83 to 85 characterised in that the turbulence inducing means is formed by a side wall of the housing adjacent to the side wall in which the inlet port is located.