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Title:
FLUID TREATMENT
Document Type and Number:
WIPO Patent Application WO/2019/186139
Kind Code:
A1
Abstract:
Fluid deaeration apparatus (101) for treating fluid in a fluid circuit of a heating or a cooling system, comprising a vessel (102), an air vent (110) and a displacing element (111). The vessel (102) has an upper end (103) and a lower end (104) opposite the upper end (103), and defines a fluid inlet port (105) through which fluid can enter the vessel (102), a fluid outlet port (106) through which fluid can exit the vessel (102), and a ventilation port (107). The displacing element (111) comprises a first opening (113), a second opening (114) and a fluid conduit (115) extending therebetween, the displacing element (111) extending between the ventilation port (107) of the vessel (102) and the air vent (110) and the fluid conduit (115) defining a condensing fluid flow path (116) therebetween. A method of forming the fluid deaeration apparatus (101).

Inventors:
COWLEY, Richard (11Port Island, Leighton Hulett DrivePort St. Franci, 6312 St Francis Bay Eastern Cape, 6312, ZA)
WILKINSON, Darren (26St Peters Avenue, Arlesey Bedfordshire SG15 6UR, Arlesey Bedfordshire SG15 6UR, SG15 6UR, GB)
Application Number:
GB2019/050857
Publication Date:
October 03, 2019
Filing Date:
March 26, 2019
Export Citation:
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Assignee:
VEXO INTERNATIONAL (UK) LIMITED (Coppergate House, 16 Brune Street, London E1 7NJ, E1 7NJ, GB)
International Classes:
B01D5/00; B01D19/00; B01D46/00; F24D19/08
Domestic Patent References:
WO2007004516A12007-01-11
Foreign References:
US4188793A1980-02-19
US2104759A1938-01-11
US3211376A1965-10-12
US4909317A1990-03-20
Attorney, Agent or Firm:
BRYERS LLP et al. (7Gay Street, Bath Bath and North East Somerset BA1 2PH, Bath Bath and North East Somerset BA1 2PH, BA1 2PH, GB)
Download PDF:
Claims:
Claims

1 . Fluid deaeration apparatus for treating fluid in a fluid circuit of a heating or a cooling system, said fluid deaeration apparatus comprising:

a vessel having an upper end and a lower end opposite the upper end, the vessel defining a fluid inlet port through which fluid can enter the vessel, a fluid outlet port through which fluid can exit the vessel, and a ventilation port for allowing gas to escape from inside the vessel;

an air vent comprising a one-way valve; and

a displacing element comprising a first opening, a second opening and a fluid conduit extending therebetween;

the displacing element extending between the ventilation port of the vessel and the air vent and the fluid conduit defining a condensing fluid flow path therebetween; wherein the fluid flow path is circuitous, and wherein the circuitous fluid flow path bends through an angle of approximately 360 degrees.

2. Fluid deaeration apparatus as claimed in claim I , wherein the circuitous fluid flow path bends around an axis that extends substantially parallel to or is coaxial with a longitudinal axis of the vessel.

3. Fluid deaeration apparatus as claimed in claim I , wherein the circuitous fluid flow path bends around an axis that extends substantially perpendicularly to a longitudinal axis of the vessel. 4. Fluid deaeration apparatus as claimed in any of claims I to 3, wherein the circuitous fluid flow path includes a spiral or helical portion through an angle of approximately 360 degrees or more.

5. Fluid deaeration apparatus as claimed in claim 3, wherein the circuitous fluid flow path includes a first portion that bends through an angle of approximately 90 degrees, a second portion that is substantially linear, and a third portion that bends through an angle of approximately 270 degrees.

6. Fluid deaeration apparatus as claimed in any preceding claim, wherein the displacement element extends into the vessel such that that an entry into the displacement element is located within the vessel.

7. Fluid deaeration apparatus as claimed in any of claims I to 6, wherein the air vent is an automatic air vent.

8. Fluid deaeration apparatus as claimed in any of claims I to 7, wherein the vessel has a longitudinal axis and a radial axis, and has a diameter that decreases in a direction along the longitudinal axis from the fluid inlet port to the fluid outlet port.

9. Fluid deaeration apparatus as claimed in any of claims I to 8, wherein the vessel has a sidewall extending between the upper end and the lower end thereof, and wherein the ventilation port is defined in the upper end, the fluid inlet port is defined in the sidewall and the fluid outlet port is defined in the lower end.

1 0. Fluid deaeration apparatus as claimed in any of claims I to 9, wherein the fluid conduit is defined by a tubular member and wherein the first opening is defined in a first end thereof and the second opening is defined in a second end thereof.

1 1 . Fluid deaeration apparatus as claimed in claim 10, wherein the tubular member is a self-supporting, manually unbendable tubular member.

1 2. A heating or a cooling system comprising fluid deaeration apparatus as claimed in any of claims I to I I .

1 3. A heating or a cooling system as claimed in claim 12, wherein the vessel is installed as a side-stream cyclonic de-aerator.

1 4. A heating or a cooling system as claimed in claim 1 3, further comprising a pump downstream of the fluid outlet port of the vessel.

1 5. A heating or a cooling system as claimed in claim 14, further comprising a filtration arrangement upstream of the fluid inlet port of the vessel, wherein the filtration arrangement comprises one or both of: a mechanical filtration filter, a permanent magnet filter.

1 6. A heating or a cooling system as claimed in claim 15, further comprising a pressure sensing arrangement for detecting a blockage in the filtration arrangement and, in response to detecting a blockage in the filtration arrangement

I 7. A method of forming fluid deaeration apparatus for treating fluid in a fluid circuit of a heating or a cooling system, said method comprising the steps of:

(i) receiving a vessel having an upper end and a lower end opposite the upper end, the vessel defining a fluid inlet port through which fluid can enter the vessel, a fluid outlet port through which fluid can exit the vessel, and a ventilation port for allowing gas to escape from inside the vessel;

(ii) receiving an air vent having a one-way valve;

(iii) receiving a displacing element comprising a first opening, a second opening and a fluid conduit extending therebetween; and

(iv) connecting the displacing element between the ventilation port of the vessel and the air vent, wherein the fluid conduit defines a condensing fluid flow path therebetween, wherein the fluid flow path is circuitous, and wherein the circuitous fluid flow path bends through an angle of approximately 360 degrees.

1 8. A method as claimed in claim 17, wherein the circuitous fluid flow path bends around an axis that extends substantially parallel to or is coaxial with a longitudinal axis of the vessel.

1 9. A method as claimed in claim 17, wherein the circuitous fluid flow path bends around an axis that extends substantially perpendicularly to a longitudinal axis of the vessel.

20. A method as claimed in any of claims 17 to 19, wherein the circuitous fluid flow path includes a spiral or helical portion through an angle of approximately 360 degrees or more.

21 . A method as claimed in any of claims 17 to 20, wherein the displacement element extends into the vessel such that that an entry into the displacement element is located within the vessel.

22. A method as claimed in any of claims 17 to 2 1 , wherein the air vent is an automatic air vent.

23. A method as claimed in any of claims 17 to 22, wherein the vessel has a longitudinal axis and a radial axis, and has a diameter that decreases in a direction along the longitudinal axis from the fluid inlet port to the fluid outlet port.

24. A method as claimed in any of claims 17 to 23, wherein the vessel has a sidewall extending between the upper end and the lower end thereof, and wherein the ventilation port is defined in the upper end, the fluid inlet port is defined in the sidewall and the fluid outlet port is defined in the lower end.

25. A method as claimed in any of claims 17 to 24, wherein the fluid conduit is defined by a self-supporting, manually unbendable tubular member and wherein the first opening is defined in a first end thereof and the second opening is defined in a second end thereof.

Description:
FLUID TREATMENT

Field of the Invention

The present invention relates to fluid treatment, in particular to apparatus for the treatment of fluid in a fluid circuit of a heating or a cooling system and more particularly to a side-stream cyclonic de-aerator for an industrial water heating or an industrial cooling water system.

Background of the Invention

Heating systems and cooling systems are known that comprise a fluid circuit through which a fluid circulates under pressure. An example of this type of system is a closed circuit industrial central heating system, in which system water flows in a loop from a boiler, through a series of hot-water radiators or emitters and then back to the boiler. Another example of this type of system is a closed-circuit industrial cooling water system, in which system water flows in a loop from a chiller, through a series of cooling-water convectors or industrial air conditioning units and then back to the chiller.

A problem found with closed circuit systems is that the circulating liquid can become contaminated, resulting in a reduction in the performance efficiency of the heating or cooling system and possibly also leading to total system failure. The most common sources of contaminants in the circulating liquid are: corrosion, sludge, limescale and microbiological growths (bacteria or fungi). Debris and sludge in the circulating liquid of a heating or cooling system can lead to blockages, leakage, and premature system failure.

Approaches to addressing the problem of circulating liquid contamination include flushing of the system to remove any debris in the fluid circuit, and introducing a treatment additive, such as an inhibitor, into circulating liquid for the purpose of preventing or resolving contamination build-up.

I Fluid treatment apparatus for treating fluid in a fluid circuit of a heating or cooling system, and a method of treating fluid in a fluid circuit of a heating or cooling system, are disclosed in UK Patent No. GB 2503762 B.

Another type of problem experienced is that of a reduction in operational efficiency due to the presence of dissolved gasses in the circulating fluid. The primary constituent of these gasses is air, of which approximately 78% is Nitrogen and approximately 2 1 % is Oxygen. It is estimated that, at a temperature of approximately 25 degrees Celsius, water will contain approximately 2.5% by volume dissolved air. The amount of air that can be dissolved in water increases with pressure and decreases with temperature. As the temperature of system water increases, a proportion of the air dissolved therein will come out of solution. As the air escapes, bubbles can form and these bubbles can impede performance. For example, the presence of bubbles on internal surfaces of the system can result in resistance to system water flow and material corrosion. In addition, bubbles trapped within the system water can cause unwanted noise.

Dissolved air in system water can also negatively impact heat transfer efficiency. Compared to water, air is known to be a superior insulator (by approximately 12 times that of water). Thus, air dissolved in system water acts as a thermal barrier between, in a heating system, the hot system water and a heat emitter, and therefore causes a reduction in system efficiency. It is therefore beneficial to reduce (whether by removal or otherwise) the amount of air dissolved in the system water, to increase the energy efficiency of the system.

A de-aerator for a water heating system is disclosed in European Patent Publication No. 2 589 885 A2. This prior art de-aerator comprises a vessel defining a chamber and having an inlet, an outlet, and a vent for directing gasses out of the chamber.

In a disclosed arrangement, the de-aerator is installed in-line with a primary water heater, a primary water circuit and at least one space heater. It is also disclosed that the de-aerator may be positioned downstream of a pump which is used to force water around the primary conduit and upstream of a valve or valves which are used to control the flow of fluid in the system.

The prior art de-aerator of European Patent Publication No. 2 589 885 A2 is described as being suitable for use in an application in which the volume of the de-aerator chamber, as a proportion of the total water in the heating system, is no more than about 0.3%. The design of the de-aerator renders it an unsuitable for use in large industrial systems, due to the non-viability of the material size increase associated with scaling the product up.

The presence of vapour in water systems is well known. The prior art de-aerator of European Patent Publication No. 2 589 885 A2 allows vaporised moisture to be released through a vent thereof.

According to Henry’s Law,“At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.” The amount of gas dissolved in solution varies directly with the partial pressure of that gas over the solution. Thus, when the partial pressure of the gas over the solution drops, the solubility of the gas in the solution drops also, to maintain the equilibrium.

As dissolved gas concentrations and partial pressures increase, deviations from Henry’s Law become apparent. This variance in behaviour is similar to deviation from the ideal gas law that is observed as pressures increase and temperatures decrease. For this reason, solutions that are found to obey Henry’s Law are sometimes called ideal dilute solutions.

An ideal solution, in which the forces between solvent and solute molecules are the same as the forces between solvent molecules, conforms to Raoult’s Law. If solvent- solute interactions are stronger than solvent-solvent interactions, the vapour pressure of the solution will be lower than calculated, the vapour pressure being the pressure exerted by the vapour above a liquid surface at a given temperature, in a closed system, when the rate of molecules leaving the surface is equal to the rate of molecules re-condensing.

A liquid may change to a vapour at a temperature below the boiling point of the liquid through a process of evaporation, through a surface phenomenon in which molecules located near the surface of a liquid possess sufficient kinetic energy to overcome the surface tension and escape from the liquid into the surroundings as vapour.

With the prior art de-aerator of European Patent Publication No. 2 589 885 A2, the pressure within the vessel is reduced to remove dissolved gasses. This creates water vapour, which escapes the vessel, along with the released gasses, via a one-way valve. The escaping water vapour is escaping system water. Over time the loss of system water translates to a lowered system pressure, which if not restored, can lead to system failure. Therefore, there is a direct relationship between the escape of water vapour from the de-aerator and the risk of potential failure of the system.

In addition, European Patent Publication No. 2 589 885 A2 discloses that the prior art de-aerator may comprise a magnetic element for removing ferrous materials from the water, and that the magnetic element may be positioned below the outlet of the vessel, or may be located in the outlet conduit or the flow conduit.

It is an objective of the invention to provide improvements in the de-aeration of fluid in a fluid circuit of a heating or a cooling system.

Summary of the Invention

According to a first aspect there is provided fluid deaeration apparatus for treating fluid in a fluid circuit of a heating or a cooling system, said fluid deaeration apparatus comprising: a vessel having an upper end and a lower end opposite the upper end, the vessel defining a fluid inlet port through which fluid can enter the vessel, a fluid outlet port through which fluid can exit the vessel, and a ventilation port for allowing gas to escape from inside the vessel; an air vent comprising a one-way valve; and a displacing element comprising a first opening, a second opening and a fluid conduit extending therebetween; the displacing element extending between the ventilation port of the vessel and the air vent and the fluid conduit defining a condensing fluid flow path therebetween; wherein the fluid flow path is circuitous, and wherein the circuitous fluid flow path bends through an angle of approximately 360 degrees.

The circuitous fluid flow path may bend around an axis that extends substantially parallel to or is coaxial with a longitudinal axis of the vessel. The circuitous fluid flow path may bend around an axis that extends substantially perpendicularly to a longitudinal axis of the vessel.

The circuitous fluid flow path may include a spiral or helical portion through an angle of approximately 360 degrees or more. The spiral or helical portion may have a variable or constant diameter. The fluid flow path may bend around a straight or curved axis.

The displacement element may extend into the vessel such that that an entry into the displacement element is located within the vessel.

The air vent may be an automatic air vent.

The vessel may have a longitudinal axis and a radial axis, and may have a diameter that decreases in a direction along the longitudinal axis from the fluid inlet port to the fluid outlet port.

The vessel may have a sidewall extending between the upper end and the lower end thereof, the ventilation port is defined in the upper end, in which the fluid inlet port is defined in the sidewall and the fluid outlet port is defined in the lower end.

The fluid conduit may be defined by a tubular member in which the first opening is defined in a first end thereof and the second opening is defined in a second end thereof.

According to a second aspect there is provided a heating or a cooling system comprising fluid deaeration apparatus according to the first aspect. The vessel may be installed as a side-stream cyclonic de-aerator.

The heating or cooling system may further comprise a pump downstream of the fluid outlet port of the vessel.

The heating or cooling system may further comprise a filtration arrangement upstream of the fluid inlet port of the vessel, wherein the filtration arrangement comprises one or both of: a mechanical filtration filter, a permanent magnet filter. The heating or cooling system may further comprise a pressure sensing arrangement for detecting a blockage in the filtration arrangement and, in response to detecting a blockage in the filtration arrangement

According to a second aspect there is provided a method of forming fluid deaeration apparatus for treating fluid in a fluid circuit of a heating or a cooling system, said method comprising the steps of: (i) receiving a vessel having an upper end and a lower end opposite the upper end, the vessel defining a fluid inlet port through which fluid can enter the vessel, a fluid outlet port through which fluid can exit the vessel, and a ventilation port for allowing gas to escape from inside the vessel; (ii) receiving an air vent having a one-way valve; (iii) receiving a displacing element comprising a first opening, a second opening and a fluid conduit extending therebetween; and (iv) connecting the displacing element between the ventilation port of the vessel and the air vent, wherein the fluid conduit defines a condensing fluid flow path therebetween, wherein the fluid flow path is circuitous, and wherein the circuitous fluid flow path bends through an angle of approximately 360 degrees.

The fluid conduit may be defined by a self-supporting, manually unbendable tubular member and wherein the first opening is defined in a first end thereof and the second opening is defined in a second end thereof.

Further particular and preferred aspects of the present invention are set out in the dependent claims. Brief Description of the Drawings

The present invention will now be more particularly described, with reference to the accompanying drawings, in which:

Figure I illustrates apparatus for treating fluid in a fluid circuit of a heating or a cooling system, according to a first example;

Figure 2 illustrates the apparatus of Figure I and additional apparatus; and Figure 3 illustrates apparatus for treating fluid in a fluid circuit of a heating or a cooling system, according to a second example.

Description

Example embodiments are described below in sufficient detail to enable those of ordinary skill in the art to embody and implement the apparatus, systems and processes described herein. It is to be understood that embodiments can be provided in many alternate forms and the invention should not be construed as limited to the specific embodiments and examples set forth herein but by the scope of the appended claims.

Apparatus 101 is shown in Figure I . The apparatus is suitable for treating fluid in a fluid circuit of a heating or a cooling system, in particular the de-aeration of fluid in the fluid circuit of the heating or the cooling system.

As will be described, the illustrated apparatus is suitable for use in side stream filtration.

Apparatus 101 comprises a vessel 1 02, the vessel 102 having an upper end, indicated at 103, and a lower end, indicated at 104, the lower end 104 being opposite the upper end 103. The vessel 102 defines a fluid inlet port 105 through which fluid can enter the vessel 102 and a fluid outlet port 106 through which fluid can exit the vessel 102. A flow of fluid from the fluid inlet port 105 to the fluid outlet port 106 can be established through the vessel 102. The vessel 102 also defines a ventilation port 107. The ventilation port 107 allows gas to escape from inside the vessel 102. Preferably, and in this embodiment, the vessel 102 is configured to encourage gas to come out of solution as fluid flows through it from the fluid inlet port 105 to the fluid outlet port 106. Vessel 102 has a longitudinal axis, indicated 108, and a radial axis, indicated 109. The vessel 102 may be profiled to shape the flow of fluid entering into it to form a vortex. In this embodiment, the vessel 102 has a diameter D that decreases in a direction along the longitudinal axis 108 from the fluid inlet port 105 to the fluid outlet port 106.

As a liquid, such as system water, flows from the fluid inlet port 105 to the fluid outlet port 106, the velocity of the flow increases, as a result of the decreasing radius of the vessel 102, and the pressure of the flow decreases, which encourages gasses, such as air, dissolved in the liquid to come out of solution. The air released from the system water can exit the vessel 102 through the ventilation port 107.

As will be described in further detail, apparatus 1 01 further comprises an air vent I 10 and a displacing element I I I . Preferably, and in this embodiment, the air vent I 10 is an automatic air vent having a one-way valve I 12.

The displacing element I I I comprises a first opening, indicated generally at I 1 3, a second opening, indicated generally at 1 14, and a fluid conduit extending therebetween, indicated generally at 1 15. In the shown arrangement, the displacing element I I I extends between the ventilation port 107 of the vessel 102 and the air vent I 10, and the fluid conduit I 15 defines a fluid flow path therebetween, indicated by arrow I 16. Also, in the shown arrangement, the displacing element I I I extends directly between the ventilation port 107 of the vessel 102; in other words, the displacing element I I I connects the air vent I 10 to the vessel 102.

The fluid flow path I 16 of the displacing element I I I is sufficient in form to cause or allow water vapour escaping the vessel 102 through the ventilation port 107 to condense within the fluid conduit I 15. For this reason, the fluid flow path of the displacing element will be referred to hereinafter as a condensing fluid flow path. Thus, the displacing element I I I advantageously serves to prevent the loss of water vapour from the system water through the air vent I 10. The condensing fluid flow path thereof functions to inhibit the loss of moisture from fluid that enters the vessel 102. The displacing element I I I spaces the air vent I 1 0 from the ventilation port 1 07 of the vessel 102 sufficiently to allow for condensation to form along an internal surface of the fluid conduit I 15, thus stopping vapour issuing through the ventilation port 107 from subsequently being discharged through the air vent I 10. This is beneficial for reducing system water loss and, in turn, reducing the need to repressurise the system and reducing the risk of potential system failure. Condensation within the displacing element I I I may return through the ventilation port 107 to re-join a flow of system water through the vessel 102.

The displacing element I I I may define a fluid conduit I 15 having any suitable dimensions and any suitable shape.

In this embodiment, the fluid conduit I 15 is defined by a tubular member I 17, with the first opening I 1 3 being defined in a first end I 18 thereof and the second opening I 14 being defined in a second end I 19 thereof. In addition, in this embodiment, the tubular member 1 17 is a self-supporting, manually unbendable tubular member. Thus, in this embodiment, the tubular member I 17 has a fixed shape. It is to be appreciated that the tubular member I 17 may be a unitary component or may comprises a plurality of component elements that together form the tubular member I 17.

According to the illustrated embodiment, the fluid flow path I 16 is circuitous. In the shown arrangement, the circuitous fluid flow path I 16 bends through an angle of approximately 360 degrees. In this illustrated example, the circuitous fluid flow path I 16 includes a first portion 120 that bends through an angle of approximately 90 degrees, a second portion 12 1 that is substantially linear, and a third portion 122 that bends through an angle of approximately 270 degrees. According to the illustrated arrangement, the first portion 120 extends into the vessel 102. As shown, the displacement element I I I extends into the vessel 102 such that an entry 123 into the displacement element I I I is located within the vessel 102. As illustrated, according to this example, the fluid flow path I 16 bends around an axis 124 that extends substantially perpendicularly to the longitudinal axis 108 of the vessel 102. As shown, the fluid conduit I 15 of the displacing element I I I , through which the fluid flow path I 16 extends, similarly bends around the axis 124 that extends substantially perpendicularly to the longitudinal axis 108 of the vessel 102.

The present invention provides apparatus for treating fluid in a fluid circuit of a heating or a cooling system as previously described, the apparatus comprising a de-aeration vessel, a one-way valve for allowing liberated gases to be released to atmosphere, and a displacing element disposed between the de-aeration vessel and the one-way valve for condensing vapour; the displacing element enables any moisture vapour escaping the de-aeration vessel to cool to a level that it condenses within the displacing element and is prevented from being released to atmosphere.

A heating or a cooling system comprising the fluid deaeration apparatus is also provided.

A method of forming apparatus for treating fluid in a fluid circuit of a heating or a cooling system is further provided, the method comprising the steps of: (i) receiving a vessel having an upper end and a lower end opposite the upper end, the vessel defining a fluid inlet port through which fluid can enter the vessel, a fluid outlet port through which fluid can exit the vessel, and a ventilation port; (ii) receiving an air vent; (iii) receiving a displacing element comprising a first opening, a second opening and a fluid conduit extending therebetween; and (iv) connecting the displacing element between the ventilation port of the vessel and the air vent, wherein the fluid conduit defines a condensing fluid flow path therebetween.

In an embodiment, the air vent is an automatic air vent.

In an embodiment, the vessel has a longitudinal axis and a radial axis, and has a diameter that decreases in a longitudinal direction from the fluid inlet port to the fluid outlet port. In an embodiment, the vessel has a sidewall extending between the upper end and the lower end thereof, the ventilation port is defined in the upper end, the fluid inlet port is defined in the sidewall and the fluid outlet port is defined in the lower end.

In an embodiment, the fluid conduit is defined by a tubular member and wherein the first opening is defined in a first end thereof and the second opening is defined in a second end thereof.

In an embodiment, the tubular member is a self-supporting, manually unbendable tubular member.

In an embodiment, the circuitous fluid flow path bends through an angle of approximately 360 degrees.

In an embodiment, the circuitous fluid flow path includes a first portion that bends through an angle of approximately 90 degrees, a second portion that is substantially linear, and a third portion that bends through an angle of approximately 270 degrees.

The apparatus 101 of Figure I may be installed within a system as original or retrofit apparatus.

Figure 2 illustrates the apparatus 101 of Figure I and additional apparatus, as will now be described.

In an application the vessel 102 of the apparatus 101 is installed as a side-stream cyclonic de-aerator with a dedicated pump 201. This allows a portion of the system water to be diverted to the vessel 102, where it is de-gassed, and then then returned in a de-aerated condition back into to the main flow of system water, under the operation of the pump 201. This gradually reduces the dilutes the amount of oxygen and other gasses in the system water; over a period of time, the entirety of the system water is de-gassed. This approach is particularly effective for larger industrial systems.

I I Additionally, and as shown in this Figure, a filtration arrangement 202 may be provided upstream of the inlet 105 of the vessel 102 of the apparatus 101. The filtration arrangement 202 may comprise one or both of a mechanical filtration filter 203 and a permanent magnet filter 204 (both are shown in this Figure). If the filtration arrangement 202 comprises a mechanical filtration filter 203, it may comprise more than one mechanical filtration filter for filtering particles of different sizes. The positioning of the filtration arrangement 202 upstream of the vessel 102 serves to prevent scouring or damage to the internal surface of the vessel 102 from any existing system debris or detritus that may enter the vessel 102, which is particularly found in systems that have suffered from severe corrosion. The filtration arrangement 202 can therefore be used to protect the apparatus 101 and help to maintain it in a fully operational condition.

Further, and as shown in this Figure, a pressure sensing arrangement 205 may be provided for detecting a blockage in the filtration arrangement 202. According to the shown example, the pressure sensing arrangement 205 comprises at least a first pressure transducer 206 for sensing pressure upstream of the filtration arrangement 202, a second pressure transducer 207 for sensing pressure downstream of the filtration arrangement 202 and a controller 208. If the pressure sensing arrangement 205 detects that there is a filter blockage, the pressure sensing arrangement 205 can generate a signal to deactivate the pump 201. Deactivating the pump 201 stops the flow of system water through the vessel 201 , and hence suspends de-aeration of system water. The filter or filters of the filtration arrangement 202 can then be checked and cleaned as necessary, and then the pump 201 reactivated to begin deaeration of system water again. As the vessel 102 has been installed as a side-stream de-aerator, maintenance of the filtration arrangement 202 can be performed without requiring the circulation of fluid in the fluid circuit of the main heating or cooling system to be interrupted.

Apparatus 301 is shown in Figure 3. The apparatus is suitable for treating fluid in a fluid circuit of a heating or a cooling system, in particular the de-aeration of fluid in the fluid circuit of the heating or the cooling system. Apparatus 301 is similar to apparatus 101 , but differs in the respect that the fluid flow path 3 16 bends around an axis 324 that extends parallel to or is coaxial with the longitudinal axis 108 of the vessel 102. As shown, the fluid conduit 3 15 of the displacing element 3 1 1 , through which the fluid flow path 3 16 extends, similarly bends around the axis 324 that extends perpendicularly to the longitudinal axis 108 of the vessel 102. In this example, the fluid flow path comprises a spiral or helical portion that extends through an angle of approximately 360 degrees or more. As also illustrated, the displacing element 3 I I may extend into the vessel 102 such that an entry 323 into the displacement element 3 I I is located within the vessel 102.

It is thus to be appreciated that the fluid conduit of fluid deaeration apparatus as described herein, when in use, may coil around an axis that is substantially vertical, substantially horizontal or that is upwardly inclined between horizontal and vertical.

It is also to be understood that the fluid flow path may comprise a spiral or helical portion, having a variable or constant diameter, and that the fluid flow path may bend around a straight or curved axis.

The displacing element of the disclosed fluid deaeration apparatus enables air to leave a deaeration vessel, with minimised pressure drop or resistance, through cooled water (which is it a lower temperature than the water in the vessel) in the fluid conduit above the deaeration vessel.

Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is to be understood that the invention is not limited to the precise embodiments and examples shown and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims.