GB2115911A - Boiler heated water system - Google Patents

Abstract

Means for making up, automatically, losses of water from a sealed and pressurised boiler heated water system includes a pump (16) for pumping water into the system and timing means (20) to prevent operation of the pump continuously, for more than a predetermined period. In this way discharge of water from the system following a major leak is limited. <IMAGE>

Description

SPECIFICATION Boiler heated water system This invention concerns a boiler heated water system, particularly, though not exclusively, a central heating system and of the kind (hereinaftertermed of the kind referred to) which is sealed and pressurised, and more particularly means for making up automatically losses of water from such a system.

Central heating systems ofthe kind referred to, although sealed, do lose waterfrom timeto time, as through small leaks or as a result of venting radiators and so on.

In this country a direct connection between the system and the mains water supply is not permitted and rather complex means for automatically making up losses of water from the system comprising a feed tank and pump and control means therefor are necessary.

One problem arises in that if there is a major leak in the system the pump will continually operate in a vain attemptto keep the system topped up, with the result that an unlimited quantity of water will be lost from the leakwithconsequentunlimited damagetothe fabric of and furnishings in the building in which the system is installed.

It is an obiectofthe present invention to provide means for making up, automatically, losses of water from a boiler heated water system ofthe kind referred to andwhich overcomes the problem aforesaid.

According to the present invention there is provided means for making up, automatically, losses of waterfrom a boiler heated water system of the kind referred to comprising a feed tank, a pump arranged and controlled to pump waterfrom thefeed tank into the system in response to a drop in pressure in the system, characterised in that timing means is provided to stop operation ofthe pump if it should run continuously for more than a predetermined period.

The invention will be further apparent from the following description, with reference to the single figure of the accompanying drawing, which shows, byway of example only, part of a central heating system incorporating means embodying the invention.

Referring now to the drawing, it will be seen that the central heating system incorporates a gas-fired boiler 10, feed and return pipes 11 and 12fora plurality of radiators (not shown), an expansion vessel 13 and a pipe 14forthe supply oftopping up water to the system. The system is sealed from atmosphere and pressurised by gas under pressure on one side of a diaphragm 15 included within the expansion vessel 13.

The pipe 14extendsfrom a pump 16 incorporating at least one non-return valve connected to a feed tank 17 which is maintained full from the mainswater supply 18 by means of a valve responsive to the level of water in the tank 17, such as a floatoperated equilibrium valve 19.

Control means generally indicated at 20 for switch ing the drive motorforthe pump 16 is provided. In known mannerthecontrol means include a pressure sensor which monitors the pressure in the system by means of a line 21 and operates to actuate the pump whenever the pressure in the system drops below a predetermined value and to stop the pump when the pressure attains a further predetermined operating value. To avoid duplication, the pressure sensor is arranged to prevent operation of the burners of the boiler 10 in the eventthatthe pressure in the system rises to a further predetermined value above the safe operating value, cabling being provided between the control means 20 and boiler lOforthis purpose.

In accordance with the invention the control means 20 incorporates an electronic timer which operates to override the switching means described above and prevent operation of the pump 16 if operation of the pump should ever continue for more than a predeter mined period of short duration, indicative of a major and continuing loss ofwaterfrom the system. In this way the supply of water to the system is discontinued and the total water loss is limited.

The feed tank need have a capacity of only one litre or so, and by proper selection of the othercompo nents the whole device can be provided in a box 30 of modest dimensions which can be wall-mounted in the vicinity of the boiler 10.

It will be appreciated that it is not intended to limit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible, without departing from the scope thereof.

1. Apparatus for making up, automatically, losses of water from a boiler heated water system of the kind referred to comprising a feed tankand a pump arranged and controlled to pump water from the feed tank into the system in response to a drop in pressure in the system, characterised in that timing means is provided to stop operation of the pump if it should run continuously for more than a predetermined period.

2. Apparatus according to claim 1 whereinsaid pump is arranged to stop operation whenever pressure in the system is restored to a predetermined operating value.

3. Apparatus according to claim 1 or claim 2 ì wherein a pressure sensor is providedforsensingthe pressure in the system and for controlling switch meansfora drive motorforthe pump.

4. Apparatus according to claim 3 wherein said pressure sensor also serves to prevent operation of the burners of the boiler ofthe central heating system.

5. Apparatus according to any preceding claim wherein said feed tank is maintained full from a mains water supply by means of a level sensitive valve.

6. Apparatus for making up, automatically, losses of water from a boiler heated water system ofthe kind referred to substantially as described herein with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Boiler heated water system This invention concerns a boiler heated water system, particularly, though not exclusively, a central heating system and of the kind (hereinaftertermed of the kind referred to) which is sealed and pressurised, and more particularly means for making up automatically losses of water from such a system. Central heating systems ofthe kind referred to, although sealed, do lose waterfrom timeto time, as through small leaks or as a result of venting radiators and so on. In this country a direct connection between the system and the mains water supply is not permitted and rather complex means for automatically making up losses of water from the system comprising a feed tank and pump and control means therefor are necessary. One problem arises in that if there is a major leak in the system the pump will continually operate in a vain attemptto keep the system topped up, with the result that an unlimited quantity of water will be lost from the leakwithconsequentunlimited damagetothe fabric of and furnishings in the building in which the system is installed. It is an obiectofthe present invention to provide means for making up, automatically, losses of water from a boiler heated water system ofthe kind referred to andwhich overcomes the problem aforesaid. According to the present invention there is provided means for making up, automatically, losses of waterfrom a boiler heated water system of the kind referred to comprising a feed tank, a pump arranged and controlled to pump waterfrom thefeed tank into the system in response to a drop in pressure in the system, characterised in that timing means is provided to stop operation ofthe pump if it should run continuously for more than a predetermined period. The invention will be further apparent from the following description, with reference to the single figure of the accompanying drawing, which shows, byway of example only, part of a central heating system incorporating means embodying the invention. Referring now to the drawing, it will be seen that the central heating system incorporates a gas-fired boiler 10, feed and return pipes 11 and 12fora plurality of radiators (not shown), an expansion vessel 13 and a pipe 14forthe supply oftopping up water to the system. The system is sealed from atmosphere and pressurised by gas under pressure on one side of a diaphragm 15 included within the expansion vessel 13. The pipe 14extendsfrom a pump 16 incorporating at least one non-return valve connected to a feed tank 17 which is maintained full from the mainswater supply 18 by means of a valve responsive to the level of water in the tank 17, such as a floatoperated equilibrium valve 19. Control means generally indicated at 20 for switch ing the drive motorforthe pump 16 is provided. In known mannerthecontrol means include a pressure sensor which monitors the pressure in the system by means of a line 21 and operates to actuate the pump whenever the pressure in the system drops below a predetermined value and to stop the pump when the pressure attains a further predetermined operating value. To avoid duplication, the pressure sensor is arranged to prevent operation of the burners of the boiler 10 in the eventthatthe pressure in the system rises to a further predetermined value above the safe operating value, cabling being provided between the control means 20 and boiler lOforthis purpose. In accordance with the invention the control means 20 incorporates an electronic timer which operates to override the switching means described above and prevent operation of the pump 16 if operation of the pump should ever continue for more than a predeter mined period of short duration, indicative of a major and continuing loss ofwaterfrom the system. In this way the supply of water to the system is discontinued and the total water loss is limited. The feed tank need have a capacity of only one litre or so, and by proper selection of the othercompo nents the whole device can be provided in a box 30 of modest dimensions which can be wall-mounted in the vicinity of the boiler 10. It will be appreciated that it is not intended to limit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible, without departing from the scope thereof. CLAIMS

1. Apparatus for making up, automatically, losses of water from a boiler heated water system of the kind referred to comprising a feed tankand a pump arranged and controlled to pump water from the feed tank into the system in response to a drop in pressure in the system, characterised in that timing means is provided to stop operation of the pump if it should run continuously for more than a predetermined period.

2. Apparatus according to claim 1 whereinsaid pump is arranged to stop operation whenever pressure in the system is restored to a predetermined operating value.

3. Apparatus according to claim 1 or claim 2 ì wherein a pressure sensor is providedforsensingthe pressure in the system and for controlling switch meansfora drive motorforthe pump.

4. Apparatus according to claim 3 wherein said pressure sensor also serves to prevent operation of the burners of the boiler ofthe central heating system.

5. Apparatus according to any preceding claim wherein said feed tank is maintained full from a mains water supply by means of a level sensitive valve.

6. Apparatus for making up, automatically, losses of water from a boiler heated water system ofthe kind referred to substantially as described herein with reference to the accompanying drawing.