GB2528787A - A condensate disposal system for disposing of condensate from a condensing fuel burning appliance, a condensing fuel burning appliance having a condensate - Google Patents

A condensate disposal system for disposing of condensate from a condensing fuel burning appliance, a condensing fuel burning appliance having a condensate Download PDF

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Publication number
GB2528787A
GB2528787A GB1512010.8A GB201512010A GB2528787A GB 2528787 A GB2528787 A GB 2528787A GB 201512010 A GB201512010 A GB 201512010A GB 2528787 A GB2528787 A GB 2528787A
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GB
United Kingdom
Prior art keywords
condensate
disposal
neutralisation
appliance
neutralising
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Granted
Application number
GB1512010.8A
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GB2528787B (en
GB201512010D0 (en
Inventor
John Thomason
Neil Jarratt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TBS BUILDING SUPPLIES Ltd
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TBS BUILDING SUPPLIES Ltd
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Publication date
Priority to GBGB1412230.3A priority Critical patent/GB201412230D0/en
Application filed by TBS BUILDING SUPPLIES Ltd filed Critical TBS BUILDING SUPPLIES Ltd
Publication of GB201512010D0 publication Critical patent/GB201512010D0/en
Publication of GB2528787A publication Critical patent/GB2528787A/en
Application granted granted Critical
Publication of GB2528787B publication Critical patent/GB2528787B/en
Expired - Fee Related legal-status Critical Current
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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT GENERATING MEANS, IN GENERAL
    • F24H8/00Fluid heaters having heat-generating means specially adapted for extracting latent heat from flue gases by means of condensation
    • F24H8/006Means for removing condensate from the heater
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/66Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24DDOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D19/00Details
    • F24D19/10Arrangement or mounting of control or safety devices
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT GENERATING MEANS, IN GENERAL
    • F24H9/00Details
    • F24H9/20Arrangement or mounting of control or safety devices or methods
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT GENERATING MEANS, IN GENERAL
    • F24H9/00Details
    • F24H9/20Arrangement or mounting of control or safety devices or methods
    • F24H9/2007Arrangement or mounting of control or safety devices or methods for water heaters
    • F24H9/2035Arrangement or mounting of control or safety devices or methods for water heaters for heaters using fluid combustibles
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24DDOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D2200/00Heat sources or energy sources
    • F24D2200/04Gas or oil fired boiler
    • Y02B30/106

Abstract

The condensate disposal system is for disposing of condensate from a fuel burning appliance such as a condensing boiler 2. The system comprises a condensate pipe 16,28,30,32,36 connectable between a condensate outlet 20 of the appliance and a disposal point 21 such as a waste pipe 34 or condensate spray nozzle. The system also includes a controller 39 and a neutraliser 22, preferably containing calcium/magnesium carbonate, that reduces the acidity of the condensate to a level safe for disposal. The controller assesses the efficacy of the neutraliser and inhibits operation of the appliance if the efficacy falls below a first predetermined level. Ideally the efficacy is assessed as falling below the first predetermined level when by a pH sensor 44 detects a rise in acidity of the condensate downstream of the neutraliser and/or a neutralising medium level sensor 46 senses that a quantity of neutralising medium falls below a given value. Stopping of the appliance is preferably by use of an electronic interlock relay that is opened by the controller to cut power to the appliance. The system may be gravity fed (figure 2) or include a condensate pump 26.

Description

A Condensate Disposal System For Disposing Of Condensate From A Condensing Fuel Burning Appliance, A Condensing Fuel Burning Appliance Having A Condensate Disposal System, and Method Of Operating A Condensing Fuel Burning Appliance
Technical Field of the Invention
The present invention relates to a condensate disposal system for disposing of condensate from a condensing fuel burning appliance, a condensing fuel burning appliance, and to a method of operating a condensing fuel burning appliance. In particular, the present invention relates to a condensate disposal system for disposing of condensate from a condensing fuel burning appliance, a condensing friel burning appliance, and a method of operating a condensing fuel burning appliance configured to safely neutralise acidic condensate.
Background to the Invention
It is known to provide fuel burning appliances, including gas or oil fired heaters such as boilers and warm air heaters, in which heat energy is recovered from hot exhaust gases produced in the combustion process by passing the gasses through a heat exchanger. As the energy is recovered, the temperature of the exhaust gases is reduced which results in water vapour in the gases condensing within the heat exchanger. The condensate must be removed from the appliance and is often taken away to a drain pipe leading to a waste disposal system or sprayed into the air.
The combustion process results in the water vapour in the exhaust gases combining with other products of combustion (e.g. NOx) so that the condensate becomes acidic water, similar to dilute nitric acid, which causes problems during disposal. For example if the drain pipe carrying the condensate is made of a corrodible material such as copper, the pipe will quickly corrode, resulting in leakage and consequent damage to the surrounding property. Another issue is the known effect of acidic water on cement, so that if the condensate comes into contact with cement, for example in the wall or foundations of a building, there may be stmctural damage which is not acceptable. Furthermore, acidic fluid can adversely affect the process of bacterial breakdown that takes place in sewage disposal systems, and so allowing acidic fluid into a sewage disposal system can be harmful.
In order to reduce the harmful effects of the acidic condensate, its level of acidity can be reduced to an acceptable level prior to disposal. This process is often referred to as "neutralisation" because the pH value of the condensate is typically raised so as to be close to pH 7, which is neutral. Whilst the pH of the condensate is raised so as to be close to 7, it will be appreciated that the terms "neutralised" or "neutralisation" and the like as used herein generally to encompass arrangements wherein the pH value of the condensate is raised sufficiently to allow for safe disposal even where the pH value remains below 7 or is increased above 7, Neutralisation can be achieved in a variety of ways. One known method is to pass the condensate through a neutralising medium such as calcium carbonate or magnesium carbonate or other alkaline substances, The process of neutralisation consumes the neutralising medium and it is necessary to replace the neutralising medium once it has been used up to ensure that acidic condensate is not released. In known arrangements the neutralising medium is checked and replenished at set servicing intervals. However, there is a risk that a service may be missed or that the neutralising medium may become depleted more quickly than expected resulting in acidic condensate being released into the environment, It would therefore be advantageous to provide a condensate disposal system for disposing of condensate from condensing fUel burning appliance which overcomes or at least mitigates the disadvantages of the known arrangements, It would also be advantageous to provide a method of operating a condensing fuel burning appliance having a condensate disposal system which overcomes or at least mitigates the disadvantages of the known methods.
Summary of the Invention
According to a first aspect of the present invention there is provided a condensate disposal system for disposing of condensate from a condensing fuel burning appliance, the condensate disposal system comprising a fluid flow path connectable to a condensate outlet of an associated appliance to direct the condensate to a disposal point, a neutralisation means to neutralise the acidity of the condensate in the flow path upstream of the disposal point, and a control system connectable to the associated condensing fuel burning appliance, wherein the control system comprises means for assessing the efficacy of the neutralisation means and is configured in use to inhibit operation of the associated fuel burning appliance in the event the efficacy of the neutralisation means is assessed as falling below a first predetermined limit or threshold.
The neutralisation means may comprise a neutralising device holding a consumable acidity neutralising medium through which the condensate is passed. In which case the control system may be operable to assess the efficacy of the neutralisation means through direct or indirect assessment of the amount of condensate passing through the neutralising medium. Where the condensate disposal system includes a pump to assist in the flow of condensate to the disposal point, the control system may be operable to monitor operation of the pump and configured to inhibit IS operation of the appliance once the pump has operated for a predetermined time-period.
Alternatively, where the condensate disposal system comprises a reservoir in the flow path within which the condensate is collected and a pump intermittently operable to pump condensate from the reservoir to the disposal point when the condensate reaches a predetermined level within the reservoir, the control system may be operable to monitor operation of the pump and configured in use to inhibit operation of the appliance once the pump has operated a predetermined number of times. In an embodiment, the control system includes means for monitoring the operating time of the appliance and is configured in use to inhibit operation of the appliance after it has been in operation for a first predetermined amount of time.
In some embodiments the neutralisation means or neutralisation device is positioned downstream of the pump in the flow path. The pump may pump condensate into the neutralising means directly by way of a pipe or conduit, or there may be further components between the pump and neutralising means, In these embodiments the relative location of the neutralisation means or device and the pump enable the condensate to be pumped from the pump into the neutralisation means or device, The neutralisation means or device may include an inlet and outlet and the means or device may be oriented in the condensate disposal system such that the inlet is at the bottom of the neutralisation means or device and the outlet is at the top. In this orientation the pump may pump condensate into the boftom of the neutralisation means or device and upwardly through the means or device to exit from the outlet at the top of the device.
The neutralisation means or device may comprise an elongate device with the inlet and outlet at opposite ends, and the device may be oriented subsequently vertically within the condensate disposal system.
In some embodiments the condensate disposed system comprises, from upstream to downstream, a reservoir, pump and neutralisation means.
In some embodiments the neutralisation means is pressurised or subjected to pressure. The neutralisation means may be pressured or be subj ected to pressure of at least 0.5 bar, 075 bar or I bar and may be up to 2 bar, 3 bar or 5 bar. Pressure may be effected by the pump and optionally a restricted fluid outlet of the neutralisation means or disposal point. The disposal point may comprise a restricted diameter outlet.
Alternatively or additionally the disposal point may comprise a valve to induce back pressure on the flow path. In some embodiments the flow path may include a valve downstream of the neutralisation means, or located on or in the region of the outlet from the neutralisation means for generating back pressure in the neutralisation means.
In an embodiment, the control system comprises means for sensing the amount of neutralising medium in the neutralising device, the control system being configured to assess the efficacy of the neutralisation means as falling below the first predetermined limit when the sensor indicates that the amount of neutralising medium has fallen to or below a given value. The control system may comprise a level sensor for detecting the level of neutralising medium in the neutralising device. The level sensor may comprise a float arranged to rest on an upper surface of the neutralising medium and a sensor means for detecting the position of the float or wherein the level sensor may comprise an ultrasonic or optical sensor arranged to monitor the upper surface of the neutralising medium. The level sensor may alternatively be a capacitive level sensor.
In an embodiment, the control system is operable to monitor the efficacy of the neutralisation means through direct or indirect measurement of the pH of the condensate downstream of the neutralisation medium. The system may comprises a pt-I sensor located within the flow path of the condensate downstream of the neutralisation medium to directly measure the pH value of the condensate or it may comprise an electrical conductivity sensor located within the flow path of the condensate downstream of the neutralisation medium to indirectly measure the pt-I of the condensate, The control system may comprise an interlock switch operable to inhibit the operation of the appliance in the event the efficacy of the neutralisation means is assessed as falling below the first predetermined limit, The interlock switch may be operative to switch the associated appliance off when activated, Where the condensate disposal system comprises a consumable neutralisation medium, the control system may have a warning system to provide an indication to a user that the neutralising medium requires replenishment, the control system being operable to activate the warning system in the event the efficacy of the neutralisation means is assessed as falling below a second predetermined limit or threshold which is higher than the first predetermined limit, The disposal point may comprise a connection to a drainage pipe, an open drain, a soak away, or spay nozzle through which the condensate is spayed into the air, In accordance with a second aspect of the invention, there is provided a condensing fuel burning appliance comprising or connected with a condensate disposal system in accordance with the first aspect, The control system may also be operative in use to control operation of the appliance during normal running. The fuel burning appliance may comprise a condensing boiler or a condensing warm air heater, In accordance with a third aspect of the invention, there is provided a method of operating a condensing fuel burning appliance comprising: a burner; a heat exchanger through which exhaust gases from the burner are passed such that water vapour in the exhaust gases is condensed; a condensate disposal system for disposing of the condensate to the environment including a means to neutralise the condensate; arid a control system for monitoring or assessing the efficacy of the neutralisation means; the method comprising: a) neutralising the condensate prior to disposal to the environment; b) using the control means to assess the efficacy of the neutralisation; and c) using the control means to inhibit operation of the appliance in the event the efficacy of the neutralisation is assessed as falling below a first predetermined limit or threshold.
The step of neutralising the condensate may comprise passing the condensate through a consumable acidity neutralising medium. In which case, the efficacy of the neutralisation may be assessed by directly or indirectly detecting or otherwise assessing the amount of condensate that has passed through the neutralising medium.
In an embodiment where the condensate disposal system includes a pump to assist in the flow of condensate through at least part of the condensate disposal system, the method may comprise monitoring operation of the pump inhibiting operation of the appliance once the pump has operated for a predetermined time-period.
In an embodiment where the condensate disposal system comprises a reservoir within which the condensate is collected and a pump intermittently operable to pump condensate from the reservoir to a disposal point when the condensate reaches a predetermined level within the reservoir, the method may comprise monitoring operation of the pump and inhibiting operation of the appliance once the pump has operated a predetermined number of times.
The step of assessing efficacy of the neutralisation may be carried out by directly monitoring the amount of condensate acidity neutralising medium in the neutrali sing device.
The step of assessing efficacy of the neutralisation may be carried out through direct or indirect measurement of the pH of the condensate after neutralisation.
Detailed Description of the Invention
In order that the invention may be more clearly understood embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure I is a schematic overview of a condensate disposal system in accordance with several embodiments of the invention together with an associated fuel burning appliance; Figure 2 is a schematic overview of an alternative condensate disposal system in accordance with several embodiments of the present invention together with an associated fuel burning appliance; and Figure 3 is a schematic overview of another condensate disposal system in accordance with several embodiments of the present invention, together with a fuel-burning appliance.
Figures 1 to 3 illustrate embodiments of a condensate disposal system t in accordance with the present invention together with an associated condensing fuel burning appliance 2.
The appliance 2 includes a burner 4 for burning a fossil fuel such as oil or gas, a heat exchanger 6, and an exhaust system S comprising an exhaust pipe or flue 10 and a discharge terminal 12. In the present embodiments, the appliance 2 is a gas fuelled condensing boiler and will be described as such hereafter. However, the features of the condensate disposal systems I described below can be adopted for use with any type of condensing fuel burning appliance such as a warm air heater and the following
description should be understood accordingly.
h use, exhaust gases (products of combustion) from the burner 4 are passed through the heat exchanger 6 where heat in the exhaust gasses is extracted. The exhaust gasses are then discharged to atmosphere through the flue 10 and discharge terminal U, Whilst Figures 1 and 2 show the flue 0 extending vertically this is not essential and the flue 10 could be a horizontal flue.
As the heat is extracted from the exhaust gasses in the heat exchanger 6, water vapour in the exhaust gases condenses to form a condensate. The condensate is collected below the heat exchanger where it passes under gravity through pipe work 16 to an outlet 20. The pipe work 16 includes a U-bend trap t8 which prevents exhaust gases escaping from the heat exchanger together with the condensate, A condensate disposal system for the appliance 2 is fluidly connected to the outlet 20 and defines a flow path through which the condensate passes to a disposal point 21 In the embodiment shown in Figure 1, the condensate disposal system 1 includes a neutralising device 22, a condensate reservoir 24, aiid a condensate pump 26 all fluidly connected in line with one another and the outlet 20 by respective pipes 28, 30, 32. The pump 26 is fluidly connected to a waste pipe 34 into which the condensate is discharged at the discharge point 21 by pipe 36. The waste pipe 34 may be part of a rain water or foul water drainage system for the building in which the heating system is located. In alternative embodiments, the condensate disposal system 1 may direct the condensate to a range of different disposal points including: a drain, external soak away, or a nozzle through which the condensate is sprayed into the air, usually outside the building in the manner described in European Patent 1734316.
The order in which the neutralisation device 22, the reservoir 24 and the pump 26 are located in the condensate disposal flow path can be varied in some embodiments.
IS In addition, a filter can also be incorporated in the flow path for condensate. In the embodiment shown in Figure 2, the condensate disposal system 1 is substantially the same as that of the embodiment in Figure 1 except that no pump 26 is required as the condensate is gravity fed, The condensate disposal system I has a control system illustrated schematically at 38. The control system 38 comprises a programmable electronic controller 39 including a Cpu and memory (not shown). The memory may be a solid state memory that retains information even when the control system is switched off for long periods, say over a summer period. In the embodiment shown in Figure 1, the control system 38 is operable to control operation of the pump 26 and to monitor and/or assess the efficacy of the neutralising device 22 and to inhibit operation of the appliance if the efficacy of the neutralising device 22 is assessed to fall below a first predetermined threshold limit as will be discussed in detail below.
The combustion process results in the water vapour combining with other products of combustion (e.g. NOx), so that the condensate becomes acidic water, In order to reduce the level of acidity of the condensate before it is discharged into the environment, the condensate is passed through a neutralising medium 40 which is contained in a canister forming part of the neutralising device 22 in the condensate flow path. The neutralising medium 40 may comprise any suitable medium which is effective to reduce the level of acidity of the condensate such as calcium carbonate or magnesium carbonate, or some metals such as aluminium, or other forms of alkaline substances.
The ph of the condensate produced in a fuel burning appliance 2 can vary but is typically in the range of 4.5 to 2. Once it has passed through the neutralising medium, its pH level is raised so that it is closer to 7, It will be appreciated that it is not essential that the condensate is strictly ph neutral after passing through the neutralising medium provided its pH level is acceptable for safe disposal in the environment. Typically this will require a pH in the range of about 6 to 8. The neutralising medium 40 is consumed as the condensate passes through it and so has to be replenished once the amount of medium has fallen below the level required to raise the pH of the condensate to an
acceptable level.
Once the condensate has passed through the neutralising device 22 it passes into IS a reservoir 24 where it is collected and is intermittently pumped from the reservoir to the waste pipe 34. The reservoir 22 includes a sensor system 42 for detecting the level of condensate in the reservoir and which is connected with the control system 38. The sensor system 42 may comprise a float switch but other suitable sensor anangements can be adopted. When the level of condensate in the reservoir 24 reaches a first predetermined level (A), the controller 39 operates pump 26 in response to an input from the condensate level sensor system until the level of the condensate within the reservoir has fallen to a second predetermined level (B). This may be detected by the condensate level sensor system 42 or the pump 26 may be operated for a predetermined amount of time calculated to bring the level of the condensate in the reservoir down to the second predetermined level (B). The pump 26 discharges the condensate into waste pipe 34.
In the event that the pump 26 fails to operate or the condensate is unable to be removed from the reservoir 24 for some other reason, such as a blockage of the flow path, the controller 39 is operative to inhibit operation of the boiler 2 in response to an input from the condensate level sensor system 42 indicative that the level of the condensate as reached a third predetermined level (C) which is greater than the first lO predetermined level (A). The control system 38 may also have a warning system, such as alight, which can be activated to indicate that there is a problem with the condensate disposal system.
The control system 38 includes an interlock switch by means of which the appliance 2 can be rendered inoperative if the level of condensate reaches the third predetermined level (C). The interlock switch may, for example, incorporate a relay through which electrical power to the appliance is directed when the relay is closed.
When the controller 39 receives an input from the condensate level sensor system 42 indicative that the level of the condensate as reached a third predetermined level (C) it opens the relay to interrupt the power supply to the boiler 2 shutting it off. The controller 39 may be programmed to make a number of attempts to operate the pump and/or clear any blockage, or may include a time delay to allow the condensate to fall to safe levels before it shuts the boiler down. The interlock may be configured so as to be automatically reset if the level of condensate in the reservoir falls back below the IS predetermined level (C), say due to a blockage in the condensate flow path being cleared. Alternatively, the interlock may require resetting by an engineer before the boiler can be restarted and the control system 38 may also include a warning system, such as a light, which is activated once the interlock switch has been tripped so as to inform the user that a service engineer must be called.
The control system 38 is also operative to inhibit operation of the boiler 2 when it assess the efficacy of the neutralising means as falling below the first predetermined limit and achieves this through the interlock switch as described above.
The term "inhibiting operation" of the condensing appliance 2 should be understood as encompassing any suitable arrangement by means of which the appliance 2 is prevented from being operated in the usual manner resulting in the production of condensate which must be discharged. Typically, the interlock switch will function to disconnect the electrical power supply to the appliance, turning it otI but other arrangements could be adopted.
In one embodiment, the efficacy of the neutralisation means is assessed by measuring the pH of the condensate after it has passed through the neutralising device, or at least the part of the device which holds the neutralising medium. Conveniently, Ii where the reservoir 24 is located downstream of the neutralisation device 22, the pH of the condensate can be measured in the reservoir. The pH of the condensate can be measured directly by means of a pH sensor forming part of the control system and indicated schematically at 44, If the control system 38 detects that the pH of the condensate falls to or below a given value, say 5.5, which represents the first predetermined limit of the efficacy of the neutralising means it activates the interlock switch to prevent operation of the boiler 2 until the system is reset, Alternatively, the pH of the condensate can be measured indirectly by means of an electrical conductivity sensor to detect the electrical conductivity of the condensate which increases as the pH value moves away from the neutral 7. In this case, the controller 39 will activate the interlock switch once the electrical conductivity reaches a pre-set limit which is indicative that the pH of the condensate has fallen to or below a value which represents the first predetermined limit of the efficacy of the neutralising means, The control system 38 may also include a warning system, such as alight, to indicate to a user when the efficacy of the neutralising means has fallen to or below a second predetermined limit which is higher than the first predetermined so that the user can arrange for a service engineer to call before the boiler 2 is inhibited by means of the interlock.
An advantage of monitoring the pH of the condensate embodiment is that the efficacy of the neutralising means is assessed directly and operation of the boiler inhibited whenever the pH value of the condensate falls to or below a preset limit regardless of the cause. A further advantage is that the system cannot be re-set to allow the boiler to continue operating without refilling the neutralising means with an effective neutralising medium or othenvise rectify operation of the neutralising means as it will automatically shut down the appliance again as soon as it detects that the pH of the condensate has fallen to or below the predetermined value, In further embodiments, the control system 38 assesses the efficacy of the neutralising means 22 indirectly by monitoring or otherwise assessing the amount of neutralising medium 40 in the neutralising device 22. When the control system 38 determines or otherwise assess that the amount of neutralising medium 40 has fallen to or below the level required to adequately neutralise the condensate, the interlock is activated to inhibit operation of the boiler 2 and the warning system activated to indicate to a user that a service engineer should be called. The control system 38 may have a further warning system which is activated when the amount of neutralising medium 40 is measured or assessed to have fallen below a second predetermined limit which is greater than the first to indicate to a user that the neutralising medium requires replenishing but before operation of the boiler is inhibited.
In one such embodiment, the amount of neutralising medium 40 is measured directly by means of a sensor, indicated schematically at 46, mounted in or to the neutralising device 22 and forming part of the control system 38. The sensor may be a level sensor for monitoring the level of neutralising medium in the neutralising device.
It could take the form of a float arranged to rest on an upper surface of the neutralising medium and a sensor means for detecting the position of the float or it could be in the form of an ultrasonic or optical sensor arranged to monitor the upper surface of the neutralising medium. Where the sensor includes a float, the float may be magnetic for example. A capacitive level sensor may also be used to sense the level of neutralising IS medium 40 in the neutralising means, h further alternative embodiments, rather than directly monitoring the amount of neutralising medium 40 in the neutralising device 22, the control system may be configured to assess (calculate or predict) when the neutralising medium 40 has been depleted to an extent that the efficacy of the neutralising means 22 will have fallen to or below the first predetermined limit based, for example, on the amount of condensate passing through the neutralising medium.
The rate at which the neutralising medium 40 is consumed can be calculated for any given friel burning appliance 2 installation dependent on its operating conditions and the type of neutralising medium 40 used. The rate at which the neutralising medium 40 is consumed is dependent on the acidity of the condensate, which in turn depends on the type of fuel being burned, the efficiency of the combustion, and the material of the heat exchanger 6. For example, a stainless steel heat exchanger may produce condensate with a pH of 3, but an aluminium heat exchanger may produce a condensate with a pH of only 4. Given the mass of neutralising medium 40 present when the boiler is first activated, or reset after the neutralisation medium has been replenished, the amount of neutralising medium 40 remaining in the neutralising device 22 can therefore be calculated/estimated as a ifinction of the amount (volume) of condensate passing though the neutralising medium 40 in the device 22.
In an embodiment, the amount of condensate passing through the neutralising medium 40 is measured directly by means of a flow meter or other sensor to monitor the flow of condensate through the condensate disposal line. Once the amount of condensate which has passed though the neutralising device 22 is determined to have reached a pre-set limit at which the neutralising medium will have been depleted to such an extent that that it is no longer effective, the interlock is activated to inhibit operation of the boiler 2. However, the flow rate of condensate produced by the boiler 2 is relatively low and so direct measurement of the flow in this manner may be difficult.
In an alternative embodiment, operation of the pump 26 is used as an indicator of the amount of condensate passing through the neutralising medium 40. The pump 26 has a known flow rate and so the amount of condensate passing through the neutralising device can be determined by monitoring the amount of time the pump is in operation.
The control system 38 monitors use of the pump and once it determines that the pump has been operated for a pre-set period of time, corresponding to a pre-set limit of condensate passing through the neutralisation medium, the interlock switch is activated to inhibit operation of the boiler 2. Where the pump 26 is operated intermittently to pump a known volume of condensate from the reservoir each time, the control system need not monitor the amount of time for which the pump is operated but may instead monitor the number of times the pump 26 is operated. In this case, the control system will be configured to actuate the interlock switch after a given number of pump operations after which the neutralising medium 40 will be expected to have been depleted to or below a safe level.
Where operation of the pump is used to assess the efficacy of the neutralising means 22, the controller 39 may be incorporated with the pump 26 as an integral unit.
In a further embodiment, the control system 38 is configured to monitor the operating time of the boiler 2 in order to assess the efficacy of the neutralising means 22. The rate at which condensate is produced by a condensing boiler 2, or other condensing fuel burning appliance, depends on the temperature at which it operates and the heat load. For example, it is known that the maximum amount of condensate a gas burning appliance will produce is 1.4 litres per 10 kWh. For any given installation then the rate of at which the appliance will produce condensate can be calculated and the number of operating hours required to produce a given volume of condensate estimated.
It is therefore possible to detenriine a maximum period of time the boiler can be operated before the neutralising medium 40 is depleted to or below a safe level. In this embodiment, the controller 38 will be configured to activate the interlock to inhibit operation of the boiler 2 after a first pre-set operating time of the boiler 2. As with previous embodiments, the controller may include a warning system to indicate to a user that the neutralising medium requires replenishment. This is activated after a second pre-set operating time of the boiler 2 which is less than the first pre-set limit so that the user can arrange to have the neutralising medium replenished before the boiler is inhibited. In this embodiment, the condensate disposal control system 38 may be connected to or formed integrally with a control system of the boiler 2 which controls the operation of the boiler 2 to turn the burner 4 on and off in response to various inputs.
Figure 2 illustrates an alternative embodiment of a condensing fuel burning appliance 2 in which the condensate disposal system t does not require the use of a pump. In this case the system I operates by gravity flow of the condensate to a suitable drain. Since no pump is required, the pump 26 is omitted. The condensate disposal control system 38 in this embodiment can operate in any of the ways described above in relation to the first embodiment in order to assess the efficacy of the neutralising means with the exception of monitoring operation of the pump which is not present.
Accordingly, in this embodiment the control system 38 may be operative to monitor the pH of the condensate, the flow rate of the condensate and/or or the operating time of the appliance (burner) itself For example, in this embodiment a simple condensate collector 24 can be provided in the condensate disposal line in which are contained sensors, such as described above for measuring the Ph of the condensate, or a flow meter, Alternatively, sensors 46 may be provided to directly monitor the amount of neutralising medium 40 in the neutralising device 22. The controller 39 receives the signals or measurements from the sensors or flow meter and is operative to inhibit operation of the boiler 2 if the efficacy of the neutralising means is assessed as having fallen to or below the first predetermined limit as described above.
IS
The control system 38, the neutralising device 22, the condensate reservoir 24, and, where present, the pump 26 may be located in a common housing to form a unit which can be mounted in close proximity to the boiler 2. The neutralising device 22 may have a condensate inlet which is accessible externally of the housing so that it can be fluidly connected to the condensate outlet 20 of the boiler by means of a suitable pipe 28. The housing also having a condensate connectable by means of a further pipe 36 to the disposal point 21 which is connected to the pump 26 when present or to the outlet of the reservoir. The housing may also have an inlet and outlet, for example in the form of cable glands, though which cables for supplying electrical power to the boiler can be introduced into the housing for connection with the relay.
Figure 3 illustrates an embodiment of a condensate disposal system of the invention similar to that of Figure 1, and like numerals represent like components.
In the appliance 2 shown in Figure 3 the neutralising device 22 is situated downstream of the pump 26. Therefore the condensate disposal system I of Figure 3 comprises, in order of upstream to downstream, a condensate reservoir 24, a condensate pump 26 and a neutralising device 22. The neutralising device 22 is fluidly connected to a waste pipe 34 into which the condensate is discharged at the discharge point 21 by the pipe 36. The neutralising device 22, condensate reservoir 24 and condensate pump 26 are as described for Figure 1, The positioning of the neutralising device 22 after (downstream) of the pump 26 is believed to have a number of technical advantages. In this embodiment, the condensate discharging from the reservoir 24 is forced through the neutralising device 22 by the pump 26 under pressure, which agitates or stirs any sediment, sludge or solid material in the neutralising device 22, which is then more easily pumped from the neutralising device 22, increasing the lifetime and effectiveness of the condensate disposal system 1. In addition the neutralising device 22 is prevented from drying out as it is constantly replenished with condensate from the pump 26, and therefore a solid surface or skin is prevented or mitigated.
In the embodiment shown in Figure 3, the neutralising device 22 is mounted vertically within the appliance 2. The condensate pumped from pump 26 enters the bottom of the neutralising device 22 and is pumped up through the device 22, discharging from the top of the device 22. This orientation and movement of the condensate causes any solid residues, such as sludge, to be agitated and forced through the device 22 at the top and into the discharge pipe 36. In addition the neutralising medium within the neutralising device 22 is also agitated, increasing its effectiveness and mitigating or removing any solid residue blockage of the medium. Since the pump 26 operates intermittently, the neutralising medium settles when static, enabling more effective neutralisation as the condensate sits in the neutralisation medium for a longer period of time, The neutralisation device 22 may be a sealed cartridge which helps to ensure that the neutralisation medium within it does not dry out. The neutralisation device 22 may be under pressure, such as 1 bar or more, which ensures that the condensate enters the neutralisation medium more effectively, thereby effecting a better neutralisation of the condensate.
It will be appreciated that Figures 1 to 3 are composite schematic representations encompassing various embodiments of the invention in each of which two or more arrangements for assessing the efficacy of the neutralising means are shown, In practice, any given installation in accordance with the invention may incorporate only one arrangement for assessing the efficacy of the neutralising means.
The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims. For example, in the embodiments described the condensate disposal control system 38 is separate from and external to the appliance 2. However, in other embodiments the condensate disposal control system 38 could be incorporated into the appliance 2 itself and may be provided as an integral part of a control system for the appliance which also controls the general operation of the appliance under normal operating conditions.

Claims (1)

  1. CLAIMSA condensate disposal system for disposing of condensate from a condensing fuel burning appliance, the condensate disposal system comprising a fluid flow path connectable to a condensate outlet of an associated appliance to direct the condensate to a disposal point, a neutralisation means to neutralise the acidity of the condensate in the flow path upstream of the disposal point, and a control system connectable to the associated condensing fuel burning appliance, wherein the control system comprises means for assessing the efficacy of the neutralisation means and is configured in use to inhibit operation of the associated fuel burning appliance in the event the efficacy of the neutralisation means is assessed as falling below a first predetermined limit.
    2. A condensate disposal system as claimed in claim t, wherein the control system includes means for monitoring the operating time of the appliance IS burner and is configured in use to inhibit operation of the appliance after it has been in operation for a first predetermined amount of time.
    3. A condensate disposal system as claimed in claim 1 or 2, wherein the neutralisation means comprises a neutralising device holding a consumable acidity neutralising medium through which the condensate is passed.
    4. A condensate disposal system as claimed in claim 3, wherein the control system is operable to assess the efficacy of the neutralisation means through direct or indirect assessment of the amount of condensate passing through the neutralising medium.
    5, A condensate disposal system as claimed in claims 3 or 4, wherein the control system comprises means for sensing the amount of neutralising medium in the neutralising device, the control system being configured to assess the efficacy of the neutralisation means as falling below the first predetermined limit when the sensor indicates that the amount of neutralising medium has fallen to or below a given value.
    6. A condensate disposal system as claimed in claim 5, wherein the control system comprises a level sensor for detecting the level of neutrali sing medium in the neutralising device.
    7, A condensate disposal system as claimed in claim 6, wherein the level sensor comprises a float arranged to rest on an upper surface of the neutralising medium and a sensor means for detecting the position of the float, or wherein the level sensor comprises an ultrasonic, or optical sensor arranged to monitor the upper surface of the neutralising medium, or a capacitive fluid level sensor.
    8, A condensate disposal system as claimed in any preceding claim, wherein the condensate disposal system includes a pump to assist in the flow of condensate to the disposal point, the control system being operable to monitor operation of the pump and configured to inhibit operation of the appliance once the pump has operated for a predetermined time-period.
    9, A condensate disposal system as claimed in any preceding claim, wherein the condensate disposal system comprises a reservoir in the flow path within which the condensate is collected and a pump intermittently operable to pump IS condensate from the reservoir to the disposal point when the condensate reaches a predetermined level within the reservoir, the control system being operable to monitor operation of the pump and configured in use to inhibit operation of the appliance once the pump has operated a predetermined number of times.
    0. A condensate disposal system as claimed in claim 8 or 9 wherein the neutralisation means is positioned downstream of the pump, such that condensate is pumped from the pump into the neutralisation means, in use.
    LI. A condensate disposal system as claimed in claim 10 wherein the neutralisation means comprises a condensate inlet and a condensate outlet, and is oriented within the system such that the inlet is positioned at the bottom of the neutralisation means and the outlet is positioned at the top of the neutralisation means, such that, in use, condensate is pumped into the inlet and upwardly through the neutralisation means, exiting the outlet at the top of the neutralisation means.
    12. A condensate disposal system as claimed in claim t t wherein the neutralisation means comprises an elongate neutralisation device having an inlet and outlet at opposite ends of the device.H, A condensate disposal system as claimed in any preceding claim, wherein the control system is operable to monitor the efficacy of the neutralisation means through direct or indirect measurement of the pH of the condensate downstream of the neutrali sation mcdi urn 14. A condensate disposal system as claimed in claim 13 comprising a pH sensor located within the flow path of the condensate downstream of the neutralisation medium to directly measure the p1-I value of the condensate.15. A condensate disposal system as claimed in claim 14 comprising an electrical conductivity sensor located within the flow path of the condensate downstream of the neutralisation medium to indirectly measure the pH of the condensate.6. A condensate disposal system according to any preceding claim wherein the control system comprises an interlock switch operable to inhibit the operation of the appliance in the event the efficacy of the neutralisation means is assessed as falling below a first predetermined limit.17. A condensate disposal system as claimed in claim 16, wherein the interlock switch comprises a relay through which electrical power to the appliance can be supplied when the relay is closed, the control system being operative to open the relay to interrupt the supply of power to the appliance in the event the efficacy of the neutralisation means is assessed as falling below a first predetermined limit.8, A condensate disposal system as claimed in claim 3 or any one of claims 4 to 14 when dependent on claim 2, wherein the control system comprises a warning system to provide an indication to a user that the neutralising medium requires replenishment, the control system being operable to activate the warning system in the event the efficacy of the neutralisation means is assessed as falling below a second predetermined limit which is higher than the first predetermined limit, 19. A condensate disposal system as claimed in any preceding claim, wherein the disposal point comprises a spay nozzle through which the condensate is spayed into the air, 20. A condensing fuel burning appliance comprising or connected with a condensate disposal system as claimed in any one of the preceding claims.2L A condensing fuel burning appliance as claimed in claim 20, wherein the control system is also operative to control operation of the appliance during normal running.22. A condensing fuel burning appliance as claimed in claim 20 or claim 21, wherein the fuel burning appliance comprises a condensing boiler or a condensing warm air heater.23. A method of operating a condensing fuel burning appliance comprising: a burner; a heat exchanger through which exhaust gases from the burner are passed such that water vapour in the exhaust gases is condensed; a condensate disposal system for disposing of the condensate to the environment including a means to neutralise the condensate; and a control system for monitoring or assessing the efficacy of the neutralisation means; the method comprising: a) neutralising the condensate prior to disposal to the environment; b) using the control means to assess the efficacy of the neutralisation; and c) using the control means to inhibit operation of the appliance in the event the efficacy of the neutralisation is assessed as falling below a first predetermined limit.24. A method as claimed in claim 23, wherein neutralising the condensate comprises passing the condensate through a consumable acidity neutralising medium.25. A method as claimed in claim 24, wherein the efficacy of the neutralisation is assessed by directly or indirectly detecting or otherwise assessing the amount of condensate that has passed through the neutralising mediumS 26. A method as claimed in claim 24 or claim 25, wherein the condensate disposal system includes a pump to assist in the flow of condensate through at least part of the condensate disposal system, the method comprising monitoring operation of the pump and inhibiting operation of the appliance once the pump has operated for a predetermined time-period.27. A method as claimed in claim 24 or claim 25, wherein the condensate disposal system comprises a reservoir within which the condensate is collected and a pump intermittently operable to pump condensate from the reservoir to a disposal point when the condensate reaches a predetermined level within the reservoir, the method comprising monitoring operation of the pump and inhibiting operation of the appliance once the pump has operated a predetermined number of times, 28. A method as claimed in claim 24, wherein the efficacy of the neutralisation is assessed by directly monitoring the amount of condensate acidity neutralising medium in the neutralising device.29. A method as claimed in claim 23 or claim 24 wherein the efficacy of the neutralisation is assessed through direct or indirect detection of the pH of the condensate after neutralisation, 30. A method as claimed in any one of claims 23 to 29 using a condensate disposal system of any one of claims ito 19 or a condensing fuel burning appliance of any one of claims 20 to 22.31. A condensate control system appliance or method as substantially described herein with reference to the accompanying drawings.
GB1512010.8A 2014-07-09 2015-07-09 A condensate disposal system, a condensing fuel burning appliance, and method of operating a condensing fuel burning appliance Expired - Fee Related GB2528787B (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020061481A1 (en) * 2018-09-21 2020-03-26 Gas Technology Institute Ultrasonic condensate neutralization and disposal system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19801066C1 (en) * 1998-01-14 1999-05-20 Viessmann Werke Kg Heating system has its gas water condensate acidity minimised by monitoring the gas temperature
JP2004286395A (en) * 2003-03-25 2004-10-14 Tokyo Gas Co Ltd Latent heat recovery type heat source machine

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19801066C1 (en) * 1998-01-14 1999-05-20 Viessmann Werke Kg Heating system has its gas water condensate acidity minimised by monitoring the gas temperature
JP2004286395A (en) * 2003-03-25 2004-10-14 Tokyo Gas Co Ltd Latent heat recovery type heat source machine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020061481A1 (en) * 2018-09-21 2020-03-26 Gas Technology Institute Ultrasonic condensate neutralization and disposal system

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GB2528787B (en) 2018-11-07
GB201512010D0 (en) 2015-08-19

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