GB2450086A

GB2450086A - Central heating systems

Info

Publication number: GB2450086A
Application number: GB0711128A
Authority: GB
Inventors: Andrew Nevin; Robert A Foster
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-06-11
Filing date: 2007-06-11
Publication date: 2008-12-17
Also published as: GB0711128D0; GB2450086A8

Abstract

An apparatus for controlling the pressure of a heating fluid within a central heating system (10, fig.1) or for controlling the flow of heating fluid into a central heating system. The apparatus comprises an inlet 46, for connection to a supply of heating fluid 42, and an outlet 64, for connection to a heating system. A pressure sensor 70 is arranged to sense the heating fluid pressure within the central heating system. A flow sensor 80 is arranged to sense the volume of heating fluid flowing between the inlet and the outlet. A flow control valve 66 controls the flow of heating fluid from the inlet to the outlet. The flow control valve is operatively connected to the pressure sensor and is arranged to open when the sensed pressure falls below a first predetermined pressure and close when the sensed pressure rises above a second predetermined pressure. Alternatively, the flow control valve is operatively connected to the flow sensor and is arranged to close once a predetermined volume of heating fluid has flowed. A self-bleeding radiator valve (82, fig.4) comprising a filter (100, fig.4) arranged to inhibit particulate matter from interfering with the operation of the valve is disclosed. A filtration device (106, fig.5) for a central heating system, preferably comprising a magnetic particle filter, is also disclosed.

Description

Title: Central heating systems

Description:

This invention relates to improvements in and relating to central heating systems.

Known central heating systems, such as those illustrated in Figures 1 and 2 of the accompanying drawings, can suffer from a number of drawbacks.

Referring to Figure 1, a known gravity-fed central heating system 10 comprises a boiler 12 and a pump 14 for, respectively, heating and pumping water around an open loop made up of supply 16 and return 18 pipes. The supply pipe 16 comprises a T-junction 20 which splits the loop into two circuits 22,24. Zone valves 26 ale located downstream of the 1-junction 20 for controlling the flow of water in each circuit 22, 24. Each zone circuit 22, 24 comprises at least one radiator 28 (although only one per loop is shown for simplicity) for dissipating heat from the water into the area surrounding the radiator 28. The temperature of each radiator can be controlled using a restrictor valve 29, which controls the flow of water thereto.

Water flows from each radiator 28 into a connaôn return pipe 18 via a second 1-junction 30, back to the boiler 12, thereby completing the loop.

The water in the loop is maintained at a constant pressure using a header tank 32. The pressure in the system is a function of the height 33 of the water level 34 in the header tank 32 above the lowest point 36 of the system. A feed pipe 38 connects the header tank 32 to the central heating system 10 via a third T-junction 40. The header tank 32 is filled using water from the mains water supply 42. The water level in the header tank is automatically topped-up using a ball cock 44.

The system can be drained by closing a mains isolator valve 46, which prevents the header tank 32 from re-filling itseIf and opening a drain valve 48. Air locks in the system can be released using bleed valves 50 fitted to each radiator 28.

Problems associated with known gravity-fed central heating systems 10 include: * Jamming open of the ball cock 44, which can lead to the header tank overflowing causing water damRge to the property.

* Jamming closed of the ball cock jams, which can cause the system to depressurise over time as water is lost through seepage.

In Figure 2, a known "closed-loop" central heating system comprises many of the same components as the gravity-fed system described in relation to Figure 1.

Identical reference numerals in Figure 2 correspond to identical components identified in Figure 1. In a closed-loop system, the mains water supply 42 is teed 52 directly into any part of the loop via an isolator valve 46, which is normally closed. A feed.

pipe 38 is also teed 40 into any part of the loop, which connects to an expansion vessel 54 for accommodating the volumetric changes as the water expands/contracts during heating/cooling. For safety reasons, the expansion vessel 54 is fitted with an auto-venting valve 56 for bleeding air out of the system and a pressure relief valve 58 for venting water in the event of over-pressurisation.

Problems associated with known closed-loop central heating systems 10 include: * Periodic checks need to be made of the system pressure and the mnins isolator 46 opened, if necessary, to top-up the system pressure.

Problems associated with all known central heating systems 10 include: * Air becoming entrained in the pipes, which collects in the radiators 28 causing them to be cool at the top. Periodic air bleeding is therefore required.

* Corrosion of any of the components of the system, which can give rise to sludge build-up, which can restrict the pipes, jam any of the valves, clog the pump and/or boiler and build-up in the radiators giving rise to system overall inefficiency.

This invention aims to address one or more of the above problems and/or to provide improvements in and relating to central heating systems.

controlling the pressure of a heating fluid within a central heating system, the apparatus comprising: an inlet for connection to a supply of heating fluid; an outlet for connection to a healing system; a pressure sensor arranged to sense the heating fluid pressure within the central heating system; and a flow control valve for controlling the operatively connected to the pressure sensor, and is arranged to open when the sensed pressure falls below a first predetermined pressure, and close when the sensed pressure rises above a second predetermined pressure.

The first and second predetermined pressures may be substantially the same.

The heating fluid may be water and the supply of heating fluid may be a mains water supply.

The apparatus may further comprise an isolator valve between the inlet and the mains water supply and/or an isolator valve between the outlet and the healing system.

The flow control valve may comprise a solenoid-actuated valve: The pressure sensor may comprise an electronic pressure gauge.

A non-return valve may be located between the flow control valve and the outlet to prevent backflow of water into the mains supply.

A dump valve may be provided between the non-return valve and the flow control valve. The dump valve may be solenoid-actuated.

The apparatus may further comprise an auto-venting valve located between the * non-return valve and the flow control valve.

According to a second aspect of the invention, there is provided a filtration device for a central heating system comprising a housing, an inlet and an outlet communicating with the interior of the housing and a filter separating the inlet and the outlet, wherein the housing comprises a transparent portion to permit visual inspection of the contents thereof.

The filtration device may comprise a magnetic filter, which may comprise a wize mesh of ferromagnetic material and a permanent magnet magnetically coupled to themesh; The ifitration device may further comprise a shade guide adjacent the transparent portion of the housing to permit the appearance of the contents of the housing to be compared therewith.

The housing of the filtration device may be manufactured of glass or a transparent plastics material.

Additionally or alternatively, the filtration device may further comprise a sensor for sensing a property (e.g. the opacity and/or colour, and/or an electrical and/or magnetic property) of the water.

According to a third aspect of the invention there is provided a selZ4,leeding radiator valve comprising a connector for sealingly connecting the valve to a radiator, aninletcommunicablewjththe interiorofaradiator, an outlet and avalvemeans *located between the inlet and the outlet for permitting egress of air, but substantially preventing the egress of water, from the radiator to the outlet, and a filter arranged to inhibit particulate matter from interfering with the operationof the valve means.

The filter is preferably located upstream of the inlet. The filter may comprise ameshalThcabletotheinlet. Theflltermaybeaniagneticfllter,e.g. awiremeshof ferromagnetic material and, optionally, a permanent magnet magnetically coupled to the mesh. The valve means may comprise a diaphragm.

According to a fourth aspect of the invention there is provided an apparatus for controlling the flow of heating fluid into a central heating system, the apparatus comprising: an inlet for connection to a supply of heating. fluid; an outlet for connection to a central heating system; a flow sensor arranged to sense the volume of heating fluid flowing between the inlet and the outlet; and a flow control valve for controlling the flow of heating fluid from the inlet to the outlet, vtherein the flow control valve is operatively connected to the flow sensor, and is arranged to close once a predetermined volume of heating fluid has flowed therethrough.

According to a fifth aspect of the invention, there is provided a management system for a central heating system comprising any one or more of the group comprising: an apparatus for controlling the pressure of a heating fluid; a ifitration device; a self-bleeding radiator valve; and an apparatus for controlling the flow of heating fluid.

According to a sixth aspect of the invention, there is provided a central heating system comprising a mnngement system.

The various advantages of the invention will be explained and/or will become apparent to the skilled person upon reading the description of the preferred embodiments that follows.

Preferred embodiments of the invention shall now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic of a known gravity-fed cenlml heating system; Figure 2 is a schematic of a knows closed-loop central heating system; Figure 3 is schematic of a pressure regulating apparatus according to the rst aspect of the invention; Figure 4 is a perspective, part-exploded view of a self.bleeding radiator valve according to an aspect of the invention; Figure 5 is a perspective view of a mngnetic particle filter according to an aspect of the invention; and Figure 6 is a schematic of a closed loop central heating system fitted with the pressure regulating apparatus of Figure 3, the selfbleeding radiator valve of Figure 4 and the magnetic particle filter of Figure 5.

In Figure 3, a pressure regulating system 60 comprises a flow pipe 62 connected at its upstream end to a mains supply 42 and at its downstream end to a feed pipe 38 of a central heating system. An upstream isolator valve 46 is provided for selectively isolating the pressure regulating system 60 from the maine supply 42 and a downstream isolator valve 64 is provided for. selectively isolating the pressure regulating system 60 from the central heating system 10. In normal use, both isolator valves 46,64 are left open.

A normally closed, in-line, solenoid actuated flow valve 66 is used for controlling the flow of mains water from the mains supply 42 into the central healing system 10 and an in-line non-return valve 68 is provided downstream of the of the flow control valve 66 to prevent water flowing back from the central heating system and contaminating the water supply 42.

A normally open, solenoid-actuated dump valve 72 is also provided downstream of the flow control valve.

An electronic pressure gauge 70 monitors the water pressure in the flow pipe 62 downstream of the non-return valve, and hence the water pressure in the central heathgsysten, 10.

The pressure gauge 70, flow control valve 66 and dump valve 72 are wired to the phase 74 and neutral 76 terminals of the boiler 12.

When the boiler fires, (i.e. when e.g. a room or tank thermostat "calls" fbr heat), electrical power is supplied to the phase 74 and neutral 76 terminals, Electric cnTent flows to the pressure gauge 70, which measures the pressure of water in the central heating system 10. If the sensed pressure is below a preset mininiwn, the pressure gauge 70 causes a relay within it to switch to an "on" position allowing electric current to energise the solenoids of the flow control 66 and the dump 72 valves. This causes the dump valve 72 to close and the flow control valve 66 to open, which causes mains water to enter the system at mains pressure. Provided the preset minimum pressure is less than mains water pressure, the water pressure within the central heating system 10 will eventually rise to the preset minimum pressure.

(Typically mains water pressure is -2.5 bar and the preset minimum pressure is -1.5 bar).

Once this happens, the relay within the pressure gauge 70 will switch back to the closed state, thereby shutting off the power to the dump 72 and flow control 66 valves, which valves return, respectively, to the open and closed positions Since the non-return valve 68 prevents water from the central heating system back flowing, only the water in the flow pipe 62 between the flow control valve 66 and the non-return valve 68 drains to waste through the dump valve 72. To facilitate this, an auto-venting valve 78 is provided to release any vacuum that may build up within the flow pipe 62.

That done, the system 60 returns to a dormant state until the next time the boiler l2flres.

control valve 66, it is possible for there to be the statutorily required "air gap" between the rnitig supply 42 and the central heating system 10 to prevent cross-contamination. The next time mains water is introduced into the flow pipe 62, any air therein vents to atmosphere via the auto-vent valve 78, thereby avoiding entraining air bubbles into the central heating system.

The pressure regulating system 60 also comprises a number of further safety features. A flow meter 80 is wired in series with the pressure gauge 70. The flow meter 80 is arranged to switch a solenoid within it to an "oft" state once a predetermined amount of water has flowed into the system. The predetermined amount of water is typically around I 1itre such that if the central heating system has developed a leak (e.g. a burst pipe, or a disconnected radiator), the system will not continue to re-fill thereby limiting the amount of water that can be released. This minimises the risk of a persistent leak, which may go undetected for some time, spiiiing large quantities of water into a building.

The pressure regulating system 60 also comprises two neon indicators 82,84 that indicate the status of the flow control 66 and the dump 72 valves. Fault may be identifiable by inspection of the neon indicators 82,84.

In Figure 4, an automatic bleed valve 82 for a radiator comprises an externally threaded cylindrical section 84th wsintothcblecdport ofaradiator28. The bleed valve 82is sealed to the radiator 28 using a strip of PTFE tape wrapped around the thread 84 and by a rubber 0-ring 86 that is squashed between the periphery of the radiator vent port and a shoulder 88 of the bleed valve 82.

The bleed valve 82 has an inlet spigot 90 that communicates with the interior of the radiator 28 and an outlet port 92 that communicates with the atmosphere. The outlet port 92 comprises a nipple 94 mounted on a movable plastic ring 96 that allows the orientation of the nipple to be adjusted depending on the rotational orientation of the bleed valve 82. Inside the bleed valve, between the inlet spigot 90 and the outlet port 92 a diaphragm (not shown) is used to allow air to, but prevent water from, flowing between the inlet 90 and the outlet 92. The diaphragm tension can be adjusted using a screw 98 on one end of the valve 82.

A magnetic particle filter 100 comprising a wire mesh basket 102 and an annular magnet 104 push-fits over the inlet spigot 90 of the bleed valve 82. The wire mesh basket 102 comprises a closed-ended cylinder of nickel wire mesh (nickel being fbrromagnetic) having an internal diameter slightly less than the external diameter of the inlet spigot 90 of the valve 82. Thus, the basket 102 friction-fits over the end of the spigot 90.

The annular magnet 104 serves to magnetize the basket 102 and thus facilitate the filtration and retention of magnetic particles (e.g. inagnetite) in the central heating water. The annular magnet 104 has a radial split 106 to enable it to be expanded to fit over the spigot 90. Thus, the annular magnet 104 also serves to act as a circip to help retainthebasket 102 insitu.

By placing a magnetic filter 102, 104 upstream of the valve inlet 90, the ingress of particulate matter can be inhibited thereby reducing the likelihood of the diaphragm of the bleed valve 82 bec mngja edopen and thereby discharging the heating fluid from the central heating system into a room.

In Figures, an in-line magnetic particle filter 106 comprises an inlet spigot 108 and an outlet spigot 110 through which central healing water flows as indicated by arrow 112. Both spigots 108, 110 have external screw threads (not shown) for connection to standard plumbing connectors. The inlet spigot 108 leads a discharge pipe 114 having a 90 degree bend therein to direct water downwards into a filter can 116. The discharge pipe which water must flow to get into the can 116. The basket 118 is magnetically coupled to a permanent magnet (not shown) which magnetises it and thereby helps to filter and retain magnetic particles from the water. The outlet spigot 112 communicates with the intenor of the can 116 to enable water that has passed through the basket 118 to flow out of the filter 106.

The filter 106 has two parts: a head part 120 into which the spigots 108, 110 are pennanently integrated, and the can 116, which is sealingly detachably connectable thereto. The can 116 is manufactured of glass or a transparent plastics material to permit the contents thereof to be visually inspected. A decal 122 is stuck to the exterior surface of the can 116, which has printed thereon, a series of differently coloured/shaded regions 124 that together make up a graduated shade guide 122.

Thus, a user can compare the colour/shade of the water inside the can 116 with the guide 122 to detennine the condition thereof. The reverse side of the decal (i.e. surface of the decal 122 that contacts the exterior surface of the can 116) also has a series of differently coloured/shaded regions 124 that together make up another graduated shade guide. The reverse side of the decal 124 can be viewed through the can and its contents (e.g. along the direction indicated by arrow 126) to visually determine the transparency of the water inside the can 116.

Furthermore, because of the flow path 112 of water within the filter 106, there are regions 128 of the can 116 in which the water flow rate is relatively low.

Sediment from the water can settle / collect in these areas. Also, the basket 118 will foul with, and collect particles (magnetic or otherwise). Thus, it is relatively easy for a user to visually assess the condition of the water in the central heating system.

Finally, Figure 6 shows how the central heating system of Figure 2 can be automaticafly maintained using the various aspects of the present invention. The central heating system shown in Figure 6 is largely the same as that shown in Figure 2. Identical features are therefore identified using the same reference numerals as in Figure 2.

In Figure 6, the pressure regulating system 60 described with reference to Figure 3 is integrated into (i.e. retrofitted to) an existing closed-loop central heating system 10. Each radiator 28 is fitted with a self-bleeding radiator valve 82 which comprises a magnetic particle filter 102, 104 upstream thereof as described with reference to Figure 4. An inline magnetic particle filter 106 as described with reference to Figure 5 is also fitted upstream of the boiler 12 and pump 14.

Thus, the central heating system shown in Figure 6prcssurises itself using the pressure regulating system 60 and vents any air build- ups using the self.bleedrng radiator valves 82. Any contaminants in the system will be apparent by visual inspection of the filter 106, and will be filtered out thereby minimidng the risk of dmmige to the components of the system 10. If a leak or burst occurs, the flow meter integrated into the pressure regulating system 60 will prevent the system 10 from being continuousiy re-filled thereby reducing the risk of flooding etc The invention is not limited to the details of the foregoing embodiments. For example, it would be possible to fit a flow conirol device 60, automatically bleeding radiatorvalves 82 and amagneticpartjeIefi1 106 toagravity-fed system. Also it is not necessary to fit a flow control device 60, an automatically bleeding radiator valves the elements may be used depending on the particular requirements dictated by circumstance Any one or more of the flow control device, the automatic radiator bleed valves and the magnetic particle filter can be fitted to a new central beating system, or retro-fitted to an existing central heating system.

Residents of privately-owned or managed properties frequently call out engineers to rectify minor faults, such as an air-filled radiator or a boiler that will not fire because the system has depressurised. The cost of such engineer call outs can be high, especially when one considers how quick and simple it can be to rectify the fault concerned.

By reducing the number of engineer call-outs needed over the lifetime of the central heating system and by ensuring that the system operates within design parameters, e.g. system pressure and air content the invention can reduce maintenance and running costs.

Claims

Claims: 1. An apparatus for controlling the pressure of a heating fluid

within a central heating system, the apparatus comprising: an inlet for connection to a supply of heating fluid; an outlet fbr connection to a heating system; a pressure sensor arranged to sense the heating fluid presswe within the central heating system; and a flow control valve for controlling the flow of heating fluid from the inlet to the outlet, wherein the flow control valve is operatively connected to the pressure sensor, and is arranged to open when the sensed pressure falls below a first predetermined pressure, and close when the sensed pressure rises above a second predetermined pressure.
2. An apparatus as claimed in claim 1, wherein the first and second predetemiined pressures are substantially the same.
3. An apparatus as claimed in claim 1 or claim 2 wherein the heating fluid is water and the supply of heating fluid is a mains water supply.
4. An apparatus as claimed in any of claims 1, 2 or 3, farther comprising an isolator valve between the inlet and the mains water supply and/or an isolator valve between the outlet and the heating system.
5. An apparatus as claimed in claim 4, wherein the flow control valve comprises a solenoid-actuated valve.
6. An apparatus as claimed in any preceding claim, wherein the pressure sensor comprises an electronic pressure gauge.
7. An apparatus as claimed in any preceding claim, further comprising a non-return valve located between the flow control valve and the outlet to prevent backflow of water into the mains supply.
8. An apparatus as claimed in claim 7, further comprising a dump valve between the non-return valve and the flow control valve.
9. An apparatus is claimed in claimS, wherein the dump valve comprises a solenoid-actuated valve.
10. An apparatus as claimed in claim S or claim 9, further comprising an auto-venting valve between the non-return valve and the flow control valve.
11. A filtration device for a central heating system comprising: a housing; an inlet and an outlet communicating with the interior of the housing; and afiltersepartingtheinetandtheow the housing comprises a transparent portion to permit visual inspection of the contents thereof
12. A filtration device as claimed in claim II, wherein the filter comprises a magnetic filter.
13. A filtration device as claimed in claim 12, wherein the magnetic filter comprises a wire mesh of fermmagnetic material and a permanent magnet magnetically coupled to the mesh.
14. A filtration device as claimed in any of claims 11, 12 or 13, further comprising a shade guide adjacent the transparent portion of the housing to permit the appearance of the contents of the housing to be compared therewith.
15. A filtration device as claimed in any of claims 11 to 14, wherein the housing is manuthctured of glass or a transparent plastics material.
16. A filtration device as claimed in any of claims 1110 15, further comprising a sensor for sensing a property of the water.
17. A filtration device as claimed in claim 16, wherein the sensor is adapted to sense the opacity and/or colour of the water.
18. A filtration device as claimed in claim 16 or claim 17, wherein the sensor is adapted to sense an electrical and/or magnetic property of the water.
19. A self bleeding radiator valve comprising a connector for sealingly connecting the valve to a radiator, an inlet communicable with the interior of a radiator, an outlet and a valve means located between the inlet and the outlet for permitting egress of air, but substantially preventing the egress of Water, from the radiator to the outlet, and a filter arranged to inhibit particulate matter from interfering with the operation of the valve means.
20.. A self-bleeding radiator valve as claimed in claim 19, wherein the filter is located upstream of the inlet.
21. A self-bleeding radiator valve as claimed in claim 19 or claim 20, wherein the filtercomprises ameshaflixableto the inlet
22. A self-bleeding radiator valve as claimed in any of claims 19, 20 or 21, wherein the filter comprises a magnetic filter.
23. A self-bleeding radiator valve as claimed in claim 22, wherein the magnetic filter comprises wire mesh of ferromagnetic mateiial and a permanent magnet magnetically coupled to the mesh.
24.' A self-bleeding radiator valve as claimed in any of claims 19 to 23, wherein the valve means comprises a diaphragm.
25. An apparatus for controlling the flow of heating fluid into a central heating system, the apparatus comprising: an inlet for connection to a supply of heating fluid; an outlet for connection to a central heating system; a flow sensor arranged to sense the volume of heating fluid flowing between the inlet and the outlet; and a flow control valve for controlling the flow of heating fluid from the inlet to the outlet wherein the flow control valve is operatively connected to the flow sensor, and is arranged to close once a predetermined volume of heating flUid has flowed therethrough
26. A management system for a central heating system comprising any one or more of the group comprising: an apparatus for controlling the pressure of a healing fluid according to any of claims 1 to 10; a filtration device according to any of claims 11 to 18; a self-bleeding radiator valve according to any of claims 19 to 24; and an apparatus for controlling the flow of heating fluid according to claim 25.
27. A central heating system comprising a management system as claimed in claim 26.
28. An apparatus for controlling the pressure of a heating fluid substantially as hereinbefore described with reference to and as illustrated in Figure 3 of the accompanying drawings.
29. A scIf.bleeding radiator valve substantially as hereinbefore described with reference to and as illustrated in Figure 4 of the accompanying drawings
30. A filtration device substantially as hereinbefore described with reference to and as illustrated in Figure 5 of the accompanying drawings.
31. An apparatus for controlling the flow of beating fluid substantially as hereinbefore described with reference to and as illustrated in Figure 3 of the accompanying drawings.
32. A management system for a central heating system substantially as heieinbefore described with reference to and as illustrated in Figure 6 of the accompanying drawings.
33. A central heating system substantially as hereinbefore described with reference to and as illustrated in Figure 6 of the accompanying drawings.