GB2432875A

GB2432875A - Freeze prevention control system for fluid supply network

Info

Publication number: GB2432875A
Application number: GB0608199A
Authority: GB
Inventors: Paul Brian Callaghan
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-10-07
Filing date: 2006-04-26
Publication date: 2007-06-06
Also published as: GB0608199D0

Abstract

An automated control system for avoiding or inhibiting the freezing of a fluid in a fluid supply or distribution network having a conduit adapted for connection to the network, a first valve to open or close the conduit such that fluid is capable of flowing from the network into the conduit, a second valve for closing the external supply of fluid to the network, a detector for detecting when the fluid is about to freeze and control means for controlling the features of the system. On activation of the system a continuous path for circulation of the fluid is created and agitation of the fluid prevents or inhibits freezing. The system is especially useful in water supply systems to domestic, commercial or industrial premises and reduces the risk of inconvenience or damage due to a frozen supply or distribution network.

Description

SYSTEM PROTECTOR

This invention relates to an automatic control system and to a method of avoiding or inhibiting the freezing of a fluid in a fluid supply or distribution network.

In fluid supply and distribution systems that are susceptible to temperature variation, it is undesirable for the fluid to freeze. This is especially the case in water supply and distribution systems water expands when it freezes. This may cause damage to pipe work or plumbing in the systems with resultant leaks from any damage on thawing.

Conventional methods of overcoming this problem include insulating or installing heat tape on the systems, both methods are time consuming and in the latter case expensive, but neither is totally effective. A need remains to provide a means by which a fluid supply and distribution system or network is protected against the drawbacks inherent in the fluid freezing.

The present inventor has now developed a system which aims to ameliorate these drawbacks by introducing an auxiliary fluid pathway which switches into operation as the fluid temperature approaches the freezing point and in use avoids or inhibits freezing of the fluid by circulating the fluid through the auxiliary pathway. The automatic control system of the invention which is suitably electrically powered, on detecting a temperature low enough to bring about the freezing of water or fluids in the supply or distribution system, brings to a halt the main fluid supply to the system and opens alternative ways in order to create an auxiliary fluid flow pathway or circuit which under normal operation is not used. The freezing process is inhibited by the agitation of any water or fluids in the systems.

The present invention provides an automated fluid control system for avoiding or inhibiting the freezing of a fluid in a fluid supply or distribution network capable of receiving an external supply of fluid, the system comprising a conduit adapted for fluid communication with the fluid network, a first valve to open or close the conduit such that fluid is capable of flowing from the network into the conduit when open and prevented from flowing when closed, a second valve for closing the external supply of fluid, a detector for detecting when the fluid is about to freeze and control means operably connected to the detector, the first valve, and the second valve the arrangement being such that at a predetermined fluid temperature above the freezing point of the fluid the second valve closes, the first valve opens and the fluid supply or distribution network downstream of the second valve and the conduit form a continuous path for circulation of the fluid and movement of the fluid is effected through the circulation path when the conduit is open whereby agitation of the fluid prevents or inhibits freezing.

Advantageously, the system activates automatically as and when temperatures approach a level at which the fluid may freeze and is not dependent on conventional means such as insulation or thermal tape, although these may be used in combination with the system as desired. In use, the automatic control system automatically initiate a sequence leading to the creation of a an auxiliary flow pathway within the conventional supply or distribution system on detecting that the fluid contained within the systems is subject to temperatures at which it may freeze. The automatic control system suitably operates so as to avoid or mitigate any loss of fluid contained within the supply and distribution system as opposed to, for example, dumping large amounts of fluid to drain when activated.

Preferably the system further comprises a pump for effecting movement of the fluid.

Other means may be employed for this purpose, for example a vacuum or venturi arrangement whereby the fluid is effectively siphoned to commence circulation, or the fluid may be circulated through a gravity-feed arrangement.

Upon activation of the system, the first and second valves may be opened or closed in any order or simultaneously as desired.

The detector may comprise any suitable means for detecting a change in the properties of the fluid, for example a change in temperature. Preferred detectors include a thermostat, thermocouple, a resistivity detector, for example a PT1 00, known to those skilled in the art, and the detector is suitably linked to a control means. As the temperature of the fluid rises above its freezing point, the detector activates the control means to close the first valve, to open the second valve and to deactivate the pump whereby the fluid network is returned to its normal operating mode. The detector suitably detects the temperature of the externally supplied fluid and, optionally, a further detector may be provided to detect the temperature of the fluid in the circulation pathway during activation of the control system.

The system according to the invention may comprise a plurality of assemblies, each assembly comprising a conduit and a first valve and the assemblies being linked in series in the circulation pathway. As desired, the system may comprise more than one external fluid supply and further comprises a second valve for each external fluid supply.

To provide for manual intervention for example in the case of emergency, maintenance or otherwise, the system suitably comprises a manual over-ride mechanism, preferably comprising at least one manual isolation valve adjacent to the one or more first valve and more preferably comprising two manual isolation valves for each first valve and disposed either side of the first valve, and also a manual override means for the control means.

In one embodiment, the fluid supply or distribution network comprises a holding vessel, for example a header tank, wherein the level of fluid is at a first position prior to activation of the control system and the level is controlled by a third valve, the vessel comprising means for detecting the level of the fluid below the first position after activation of the control system, the said means for detection being operably linked to the control means such that upon activation of the means for detection, the control means then activates the pump thereby to circulate the fluid in the system. Suitably, the means for detection is a float switch. The holding vessel also suitably comprises a drain outlet at a level below the means for detection which is valve controlled and the valve is linked to and controlled by the control means. Upon activation of the control system the valve-controlled drain outlet is suitably opened whereby the water level drops until the means for detection is activated and activates the control means for operation of the pump.

The term "circulation pathway" includes any arrangement where the fluid may circulate through the system including where the pathway is not defined continuously along its length, for example with one end of a conduit feeding a holding vessel and the pathway continuing by means of an outlet from the holding vessel. The term "circulation pathway" also includes a direct feed arrangement whereby the fluid in the fluid supply and distribution network circulates in a closed pathway not involving a holding vessel.

Suitably, the control means comprises a power saving thermostat adapted to activate the power supply to the control means at a temperature higher than the pre-determined temperature whereby the system is activated at the pre-determined temperature. Power is suitably supplied to the control means only when required for activation or deactivation of the system. Preferably, the control means comprises a secondary power supply. As desired, the control means may comprise a facility for the remote operation of the control means. The control means may also serve to control one or more additional automatic control systems and may also be employed to other devices, for example a boiler, to provide co-ordinated control.

The control means is linked to the first and second valve, the detector for example a thermostat, and if present the circulation means, for example a pump Where other preferred features, for example a float switch are included in the control system, they are suitably linked to the control means to provide full system control through the control means. The control means may comprise a user display providing a visual indication of whether the automatic control system is operating or not. The control means suitably comprises a control panel which is manually operable. The control means may be linked to at least one external control circuit and optionally includes a power output available for supply to external control circuits. The power output suitably has at least one voltage option available for supply to external circuits. The control means may comprise secondary or auxiliary circuits as desired to provide for remote, wireless, mimic or satellite control means and or alerts, e.g. to a mobile phone.

In an especially preferred embodiment the invention provides an automatic control system for avoiding or inhibiting the freezing of the water in a water supply or distribution network supplied by an external water main, the system comprising a conduit adapted for fluid communication with the network, a first valve to open or close the conduit such that water is capable of flowing from the network into the conduit when open and prevented from flowing when closed, a second valve for closing the water main supply, circulation means to effect movement of the water when the conduit is open, a detector for detecting the temperature of the mains water supply and control means operably connected to the detector, the first valve, the second valve and the circulation means the arrangement being such that at a predetermined temperature above 0 C the second valve closes, the first valve opens and the network downstream of the second valve and the conduit form a continuous path for circulation of the water whereby agitation of the water prevents or inhibits freezing.

Suitably, the water supply or distribution network comprises a header tank having a float valve and wherein the tank comprises a float switch which is below the level of the water when the float valve is closed and which is operably linked to the control means so as to activate or deactivate the circulation means, and the header tank further comprises a valve controlled outlet flow at or below the float switch wherein upon activation of the system, the control means activates the outlet flow so the water level in the tank reduces to the level of the outlet flow and thereby activates the float switch and the circulation means, and water flows continuously as a part of the circulation pathway through the float valve into the header tank until deactivated by the the control means.

The water supply and distribution network may also be linked to a boiler and the control means also controls the boiler.

In a further aspect, the invention provides an automated control system kit for retrofitting to a fluid supply or distribution network comprising a conduit adapted to connect in fluid communication with the fluid network, a first valve to open or close the conduit, a second valve adapted for fitting to the fluid network such that, in use, an external supply of fluid into the network is prevented, a detector adapted to, in use, detect when the fluid in the network is about to freeze and control means adapted to be operably connected to the detector, the first valve and the second valve and optionally instructions for the installation and/or operation of the system.

In a further aspect, the invention provides a method of inhibiting or avoiding the freezing of a fluid in a fluid supply or distribution network capable of receiving an external supply of fluid, the method comprises: a. detecting the temperature of the external supply of fluid; b. at a pre-determined temperature above the freezing point of the fluid, automatically activating a control system, the system comprising a conduit in fluid communication with the fluid network, a first valve to open or close the conduit such that fluid is capable of flowing from the network into the conduit and a second valve for closing the external supply of fluid whereby the supply or distribution network downstream of the second valve and the conduit form a continuous path for circulation of the fluid, the activation of the control system comprising the following steps; i. closing the second valve to prevent further external supply of fluid; ii. opening the first valve to open the circulation pathway; iii. effecting movement of the fluid around the circulation pathway whereby agitation of the fluid prevents or inhibits freezing.

Suitably, the method further comprises the steps of: c. monitoring the temperature of the external supply of fluid until it reaches a temperature higher than the pre-determined temperature; d. closing the first valve and e. opening the second valve whereby normal supply and or distribution of the fluid is recommenced.

The system of the invention may be employed in any suitable environment but is especially useful in protecting water supply and distribution networks in domestic and commercial buildings and industrial environments, for example manufacturing plant The nature of the external fluid supply is not critical and may be a water main or may be directly from a reservoir or supply tank.

The invention will now be illustrated by reference to the accompanying drawings: Figure 1 shows a schematic drawing of a conventional domestic plumbing arrangement on three levels without the control system of the invention.

Figure 2 shows a schematic drawing of the same arrangement as figure 1 with the addition of the automatic control system installed on the water supply system.

Figure 3 shows a schematic drawing of the same arrangement as figure 2 with a more comprehensive automatic control system installed (additional thermostat).

Figure 4 shows a schematic drawing of the same arrangement as figure 3 but now incorporates control of the heating system into the automatic control system through an auxiliary.

Figure 5 shows a schematic drawing of the flow path of water in the distribution network when the control system is not active.

Figure 6 shows a schematic drawing of the flow path of water in the system when the automatic control system is activated.

Figure 7 shows a schematic diagram of the automatic control system with relation to Figure 4.

Figure 8 shows a schematic diagram of the automatic control system installed on a direct feed water supply system (no water cistern).

Figure 1 depicts a domestic plumbing arrangement on three levels. In this arrangement there is no automatic control system, if the temperature of the water supply were to fall below zero degrees centigrade any water contained in the supply and or circulation systems would be subject to the freezing process, with a strong possibility of subsequent damage to the systems.

H

The components and symbols depicted in each figure are numbered as follows: 1. Cold water supply pipe work.

2. Hot water supply pipe work.

3. Heating circuits.

4. Overflow pipes.

5. Vent pipes.

6. Stop valves.

7. Cold water cistern.

8. Expansion tank.

9. Boiler.

10. Drain facilities.

11. Main stop cock.

12. Hotwatertank.

13. Central heating pump.

14. Water main.

15. Radiators.

16. Manual isolation valves (nb).

17. Manual isolation valves (nb).

18. Automated valves (n/c).

19. Automated valve (nb).

20. Float switch.

21. Pump.

22. Control circuits.

23. New plumbing.

24. Thermostats.

25. Power saving thermostat.

26. Control panel.

27. New plumbing.

28. Alternative new plumbing.

29. Ball cock valve position.

30. Ball cock valve position.

31. Hot water tank heating circuit.

32. Automated valve (n/c). *1 8

33. Water level.

34. Water level.

35. New plumbing.

36. Flow path of water.

37. Fuse.

38. Transformer.

39. Relay.

40. Manual overrides.

41. Status indicator Figure 2 shows a typical modern plumbing arrangement on three levels with the automatic control system installed in the water supply system. New pieces of plumbing 23 and 35 are installed between the cold water supply pipe work 1 and the hot water supply pipe work 2 creating a path between them. Comprising part of the new plumbing 23 and 35, are normally closed automated valves 18, and manual isolation valves 17, the isolation valves 17 are left open at all times except for maintenance of the systems, the new plumbing 23 also includes a pump 21, the new plumbing 23 is connected at the first supply facility immediately after the water main 14.

The new plumbing 35 is ideally but not necessarily to be connected between the furthest hot and cold supply facility from the cold water cistern 7.

The automated valves 18 and the pump 21 are connected to the control panel 26 via a control circuit 22 the new plumbing 23 and 35 must be sited after isolation valves 16 if present, automated valves 18 must be sited between the manual isolation valves 17 on both new pieces of plumbing 23 and 35 The pump 21 is also sited between the manual isolation valves 17 on the new plumbing 23.

An automated valve 19 which is open under normal use is installed at the water main 14 after the main stop cock 11 and before the first branch off the water main 14 the valve 19 is connected to the control panel 26 via a control circuit 22.

Two strategically placed thermostats are 24 are connected to the control panel 26 via a control circuit 22.

Plumbing 27 is attached to the cold water cistern 7 at a slightly lower level than the normal operating level 33, comprising part of this new plumbing 27 is a normally closed automated valve 32 and a manual isolation valve 17 to be left open at all times except for maintenance, valve 32 is connected to the control panel 26 via a control circuit 22. The new plumbing 27 can be attached to the overflow pipe 4 (via alternative new plumbing 28) at a lower level or preferably feed directly to a vessel so as to utilise any displaced water, e.g. water butt.

A float switch 20 is installed on the cold water cistern 7 at a level just above the level at which the new plumbing 27 is attached and is connected to the control panel 26 via a control circuit 22.

On detection of a preset threshold temperature (i.e. switching) by any of the thermostats 24, the control panel is signalled via a control circuit 22 a sequence is initiated and the control panel 26 via control circuits 22 begins its operations. The automated valves 18 are activated and open creating an open path between the hot water supply pipe work 2 and the cold water supply pipe work 1. The automated valve 19 is activated and closes preventing any further supply from the water main 14. The automated valve 32 is activated and opens, the water level -33 in the cold water cistern 7 now drops to a new water level 34. In its original position ball cock valve 29 was closed due to water level 33 keeping it closed, now however it is lower at ball cock valve position 30 and is open.

A temporary circuit has been created in the water systems, the float switch 20 now operates at water level 34 and signals the control panel 26 via a control circuit 22 to enable the pump and begin circulation of water in the systems. Valve 32 remains open until deactivation of the control panel 26. This ensures that no unnecessary slosh or turbulence occurs in the tank and thereby prevents the continuous operation of switch 20.

The pump 21 circulates the water in the systems by pumping water up to the cold water cistern 7 via the open ball cock valve position 30 the cold water cistern 7 in turn feeds both hot water supply pipe work 2 and cold water supply pipe work 1 which now form a circuit.

On deactivation of the automatic control system which is usually determined by the thermostats 24 rising above the preset threshold temperature, the control panel 26 deactivates and all components are de-energised, returning the water systems to normal function. The automatic control system will revert to monitoring as before, and is ready to operate again with no resets of any functions needed.

Figure 3 includes more comprehensive automatic control system than shown in Figure 2 including a power saving thermostat 25 connected to the control panel 26 via a control circuit 22. The function of this is to restrict the power supply to the control panel 26 until a specific preset temperature threshold is reached. This temperature threshold must always be set at a greater value than any other thermostat 24 setting comprising a part of the automatic control system.

The purpose of thermostat 25 is to reduce energy consumption by only enabling supply of power to the control panel 26 and consequently the rest of the automatic control system as and when it may be needed, i.e. when a particular low predetermined ambient temperature is detected.

Figure 4 contains the elements of the automatic control system shown in Figure 3 but also shows the central heating boiler 9 connected to the control panel 26 via a control circuit 22 the boiler is now incorporated into the automatic control system and can now be controlled and utilised through an auxiliary circuit in control panel 26 this will protect the domestic heating circulation system when the automated control system is activated, in this case the circulation system is a set of radiators 15 and associated pipe work.

The auxiliary functions that can be incorporated into the control panel 26, are of course numerous and can be requirement specific. A few examples are listed below:- 1. The cutting of power to sensitive areas.

2. Activation of an alarm.

3. Enabling a heating system.

This description is illustrative and not limiting of the invention. An automatic control system according to the invention may be incorporated into new networks as they are constructed or retro-fitted to existing fluid supply and distribution networks. ii

Claims

CL IS

1. An automated fluid control system for avoiding or inhibiting the freezing of a fluid in a fluid supply or distribution network capable of receiving an external supply of fluid, the system comprising a conduit adapted for fluid communication with the fluid network, a first valve to open or close the conduit such that fluid is capable of flowing from the network into the conduit when open and prevented from flowing when closed, a second valve for closing the external supply of fluid, a detector for detecting when the fluid is about to freeze and control means operably connected to the detector, the first valve, and the second valve the arrangement being such that at a predetermined fluid temperature above the freezing point of the fluid the second valve closes, the first valve opens and the fluid supply or distribution network downstream of the second valve and the conduit form a continuous path for circulation of the fluid and movement of the fluid is effected through the circulation path when the conduit is open whereby agitation of the fluid prevents or inhibits freezing.

2. A system according to claim 1 which further comprises a pump for effecting movement of the fluid through the circulation path when the conduit is open and wherein the pump is operably connected to the control means.

3. A system according to claim 1 or claim 2 in which the detector activates the control means to close the first valve, to open the second valve and to deactivate the pump at a temperature above the pre-determined temperature.

4. A system according to any one of the preceding claims comprising a plurality of assemblies, each assembly comprising a conduit and a first valve and the assemblies being linked in series in the circulation pathway.

5. A system according to any one of the preceding claims in which there is more than one external fluid supply and the system further comprises a second valve for each external fluid supply.

6. A system according to any one of the preceding claims comprising at least one manual isolation valve adjacent to the one or more first valve.

7. A system according to any one of the preceding claims in which the detector detects the temperature of the externally supplied fluid and, optionally, a further detector is provided to detect the temperature of the fluid in the circulation pathway during activation of the control system.

8. A system according to any one of the preceding claims in which the fluid supply or distribution network comprises a holding vessel wherein the level of fluid is at a first position prior to activation of the control system and the level is controlled by a third valve, the vessel comprising means for detecting the level of the fluid below the first position after activation of the control system, the said means for detection being operably linked to the control means such that upon activation of the means for detection, the control means then activates the pump thereby to circulate the fluid in the system.

9. A system according to claim 8 in which the means for detection is a float switch.

10. A system according to any one of the preceding claims in which the control means comprises a user display.

11. A system according to any one of the preceding claims in which the control means comprises a power saving thermostat adapted to activate the power supply to the control means at a temperature higher than the pre-determined temperature.

12. A system according to any one of the preceding claims in which the control means comprises a secondary power supply.

13. A system according to any one of the preceding claims in which the control means comprises a facility for the remote operation of the control means.

14. A control system according to any one of the preceding claims in which the control means also serves to control one or more additional automatic control systems.

15. An automatic control system for avoiding or inhibiting the freezing of the water in a water supply or distribution network supplied by an external water main, the system comprising a conduit adapted for fluid communication with the network, a first valve to open or close the conduit such that water is capable of flowing from the network into the conduit when open and prevented from flowing when closed, a second valve for closing the water main supply, circulation means to effect movement of the water when the conduit is open, a detector for detecting the temperature of the mains water supply and control means operably connected to the detector, the first valve, the second valve and the circulation means the arrangement being such that at a predetermined temperature above 0 C the second valve closes, the first valve opens and the network downstream of the second valve and the conduit form a continuous path for circulation of the water whereby agitation of the water prevents or inhibits freezing.

16. A system according to claim 15 in which the water supply or distribution network comprises a header tank having a float valve and wherein the tank comprises a float switch which is below the level of the water when the float valve is closed and which is operably linked to the control means so as to activate the circulation means, and the header tank further comprises a valve controlled outlet flow at or below the float switch wherein upon activation of the system, the control means activates the outlet flow so the water level in the tank reduces to the level of the outlet flow and thereby activates the float switch and the circulation means, and water flows continuously as a part of the circulation pathway through the float valve into the header tank until deactivation of the system which occurs at a predetermined temperature above 0 C at which point the outlet flow valve and circulation means are deactivated by the control means.

17. A system according to claim 15 or 16 in which the water supply and distribution network is linked to a boiler and the control means also controls the boiler.

18. An automatic control system substantially as herein described with reference to the drawings.

19. An automated control system kit for retrofitting to a fluid supply or distribution network comprising a conduit adapted to connect in fluid communication with the fluid network, a first valve to open or close the conduit, a second valve adapted for fitting to the fluid network such that, in use, an external supply of fluid into the network is prevented, a detector adapted to, in use, detect when the fluid in the network is about to freeze and control means adapted to be operably connected to the detector, the first valve and the second valve and optionally instructions for the installation and/or operation of the system.

A method of inhibiting or avoiding the freezing of a fluid in a fluid supply or distribution network capable of receiving an external supply of fluid, the method comprises: a. detecting the temperature of the external supply of fluid; b. at a pre-determined temperature above the freezing point of the fluid, automatically activating a control system, the system comprising a conduit in fluid communication with the fluid network, a first valve to open or close the conduit such that fluid is capable of flowing from the network into the conduit and a second valve for closing the external supply of fluid whereby the supply or distribution network downstream of the second valve and the conduit form a continuous path for circulation of the fluid, the activation of the control system comprising the following steps; i. closing the second valve to prevent further external supply of fluid; ii. opening the first valve to open the circulation pathway; iii. effecting movement of the fluid around the circulation pathway whereby agitation of the fluid prevents or inhibits freezing.

21. A method according to claim 20 which further comprises the steps of: c. monitoring the temperature of the external supply of fluid until it reaches a temperature higher than the pre-determined temperature; d. closing the first valve and e. opening the second valve whereby normal supply and or distribution of the fluid is recommenced.