US20110192180A1 - Frost protection system for condensate drain pipe - Google Patents

Frost protection system for condensate drain pipe Download PDF

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Publication number
US20110192180A1
US20110192180A1 US13/021,095 US201113021095A US2011192180A1 US 20110192180 A1 US20110192180 A1 US 20110192180A1 US 201113021095 A US201113021095 A US 201113021095A US 2011192180 A1 US2011192180 A1 US 2011192180A1
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United States
Prior art keywords
drain pipe
heater
pipe
controller
condensate drain
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US13/021,095
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English (en)
Inventor
Philip Rex HENDERSON
James Ian HENDERSON
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Haven Ltd
Original Assignee
Haven Ltd
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Filing date
Publication date
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Assigned to HAVEN LIMITED reassignment HAVEN LIMITED ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: Henderson, James Ian, Henderson, Philip Rex
Publication of US20110192180A1 publication Critical patent/US20110192180A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
    • F24F13/22—Means for preventing condensation or evacuating condensate
    • F24F13/222—Means for preventing condensation or evacuating condensate for evacuating condensate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D19/00—Details
    • F24D19/0095—Devices for preventing damage by freezing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/89—Arrangement or mounting of control or safety devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/10—Control of fluid heaters characterised by the purpose of the control
    • F24H15/136—Defrosting or de-icing; Preventing freezing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/20—Control of fluid heaters characterised by control inputs
    • F24H15/258—Outdoor temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
    • F24H15/355—Control of heat-generating means in heaters
    • F24H15/37—Control of heat-generating means in heaters of electric heaters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H8/00—Fluid heaters characterised by means for extracting latent heat from flue gases by means of condensation
    • F24H8/006—Means for removing condensate from the heater
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00—Details
    • F24H9/16—Arrangements for water drainage 
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00—Details
    • F24H9/20—Arrangement or mounting of control or safety devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00—Details
    • F24H9/20—Arrangement or mounting of control or safety devices
    • F24H9/2007—Arrangement or mounting of control or safety devices for water heaters
    • F24H9/2035—Arrangement or mounting of control or safety devices for water heaters using fluid fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
    • F25D21/04—Preventing the formation of frost or condensate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
    • F25D21/14—Collecting or removing condensed and defrost water; Drip trays
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F24F11/41—Defrosting; Preventing freezing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
    • F24F13/22—Means for preventing condensation or evacuating condensate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
    • F24F13/22—Means for preventing condensation or evacuating condensate
    • F24F13/222—Means for preventing condensation or evacuating condensate for evacuating condensate
    • F24F2013/227—Condensate pipe for drainage of condensate from the evaporator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2221/00—Details or features not otherwise provided for
    • F24F2221/34—Heater, e.g. gas burner, electric air heater
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]

Definitions

  • This invention relates to a frost protection system for an apparatus having a condensate drain pipe.
  • the condensate drain pipe When the condensate drain pipe is routed externally of the building, the condensate can, in cold weather, freeze in the drain pipe and block it. The condensate can then back up in the drain pipe to the apparatus. This can result in reduced efficiency of the apparatus, tripping-out of the apparatus and/or damage to the apparatus. It can also result in the drain pipe splitting or having its joints forced apart.
  • Some plumbers carefully route the drain pipe externally of the building so that it always has a fall and/or use a pipe with an excessively large internal diameter in an attempt to prevent freezing of the condensate and blocking of the pipe. However, these attempts are rarely successful and/or they result in the appearance of the outside of the building being spoiled and/or they result in an increased cost of the drain pipe. It is, of course, possible to lag the drain pipe. Although lagging may help during a brief cold snap, it has little effect during prolonged cold spells. Also, lagging adds to the cost and makes the pipe more obtrusive
  • An aim of the present invention is to prevent freezing in cold weather of condensate in such drain pipes and to do so in a convenient and unobtrusive way.
  • a frost protection system for an apparatus having a condensate drain pipe, the system comprising: a temperature sensor; a heater (for example an electrical heater); and a controller for activating the heater in dependence upon the temperature sensed by the sensor (for example to activate the heater when the sensed temperature falls below a threshold value).
  • the heater is in the form of a flexible line (for example an electrical cable with a resistive filament) for disposal in the drain pipe, and the system further comprises a fitting for the drain pipe to enable the flexible line, or a connection between the controller and the flexible line, to pass from the controller to the inside of the pipe.
  • a building having: an external wall; an apparatus (such as a boiler, a refrigerator, a freezer and an air-conditioning unit) disposed inside the building and having a condensate drain pipe that passes through a hole in the wall; and a frost protection system according to the first aspect of the invention.
  • the sensor is disposed outside the building; the fitting is fitted to the condensate drain pipe inside the building; and at least part of the heater is disposed inside the condensate drain pipe outside the building.
  • the controller can activate the heater to produce heat inside the drain pipe and thus reduce the risk of the condensate freezing. Because the heat is produced inside the pipe, it can act more directly on the water and less directly on the air surrounding the pipe than if the pipe were heated from the outside, and thus the amount of heat required is less. It is expected that, with the invention, it will even be possible to reduce the diameter of the drain pipe compared with the size that is typically used absent the invention. In addition to reducing the pipe cost, reducing the pipe size results in less air being heated in the pipe and possibly convecting the heat away.
  • the fitting is in a form of a tee or coupler having first and second portions for connection to a first upstream portion and a second downstream portion, respectively, of the condensate drain pipe and a third portion to enable entry of the flexible line or the connection therefor.
  • the tee or coupler may also have a fourth portion arranged to be fitted to a further pipe having a larger internal diameter than the external diameter of the second portion of the condensate drain pipe so that the second portion of the condensate drain pipe can run inside the further pipe. It has been found that less heat is required to prevent freezing of the condensate in a smaller diameter pipe (for example of 10 mm diameter compared to 22 mm diameter).
  • the air gap that remains between the inner second portion of the condensate drain pipe and the further outer pipe provides thermal insulation which reduces heat loss from the inside of the inner second portion of the condensate drain pipe.
  • the system is preferably provided in combination with the second portion of the condensate drain pipe. It has been found that less heat is required to prevent freezing of the condensate the fewer the number of cold joints in the condensate drain pipe. Therefore, the second portion of the condensate drain pipe is preferably flexible (for example a length of polyethene hose). Accordingly, despite any elbows that may be required in the further pipe, the second portion of the condensate drain pipe can wind its way along the inside of the further pipe without any joints.
  • the second portion of the tee or coupler is preferably provided as a separate element which is arranged to be connected to the remainder of the tee or coupler when the further pipe is fitted to the fourth portion of the tee or coupler.
  • This enables, for example, a conventional 22 mm equal tee to be employed having (i) one limb to receive the 22 mm upstream portion of the condensate drain pipe, (ii) another limb to receive the flexible heater line (or the connection between the controller and the flexible heater line), and (iii) a further limb to receive both the separate element (to which the 10 mm flexible hose is attached) and the 22 mm further pipe.
  • the line is preferably a coaxial cable, and the resistive filament preferably forms a central core of the coaxial cable.
  • the controller may be operable to control the current flow through the resistive filament or the voltage applied across the resistive filament.
  • the resistance of a resistive filament is proportional to its length. With a particular voltage applied between the ends of the filament, the heat production per unit length is inversely proportional to the square of the length of the filament. If voltage control alone is employed, there is a risk that with short lengths of filament, the filament may become excessively hot and damage its insulation. To avoid this, if voltage control is employed, the system may further include a limiter for limiting the flow of electrical current through the resistive element. For a particular limited current flowing through the filament, the heat production per unit length is independent of the length of the filament.
  • the controller is preferably operable to control the heater in dependence upon the amount by which the sensed temperature is below a threshold value, for example, increasing the heating effect linearly the greater the temperature difference.
  • the controller preferably employs pulse-width modulation to control the heater.
  • the system will typically include a sensor line for connecting the sensor to the controller.
  • the first-mentioned fitting may be arranged also to enable the sensor line to pass from the controller to the inside of the condensate drain pipe.
  • the system may further include a second fitting to enable the sensor line to pass from the controller to the inside of the condensate drain pipe. In either case, it becomes unnecessary to drill a further hole through the wall so that the sensor line can pass through the wall. If the sensor line passes along the inside of the condensate drain pipe, the sensor may be sited in the pipe, but preferably beyond the far end of the heater, or the sensor may be sited beyond the far end of the drain pipe. Alternatively, such a second fitting may be used to enable the sensor line to pass, outside the building, from the inside of the condensate drain pipe to the sensor outside the pipe.
  • FIG. 1 is a schematic diagram of a first embodiment of the invention
  • FIG. 2 is a schematic diagram of a second embodiment of the invention.
  • FIG. 3 is a schematic diagram of a third embodiment of the invention.
  • FIG. 4A is a sectioned side view of a first example of a fitting for the drain pipe
  • FIGS. 4B & C are isometric views of a hung of the fitting of FIG. 4A in relaxed and compressed states respectively;
  • FIG. 5A is a sectioned side view of a second example of a fitting for the drain pipe
  • FIGS. 5B & C are isometric views of a gland member of the fitting; of FIG. 5A in relaxed and compressed states respectively;
  • FIG. 6A is a sectioned side view of a third example of a fitting for the drain pipe
  • FIGS. 6B & C are isometric views of a bung of the fitting of FIG. 6A in relaxed and compressed states respectively;
  • FIG. 7 is a sectioned side view of a fourth example of a fitting for the drain pipe.
  • FIG. 8 is a sectioned side view of a fifth example of a fitting for the drain pipe
  • FIG. 9 is an exploded sectioned side view of a sixth example of a fitting and an alternative drain pipe.
  • FIG. 10 is similar to FIG. 9 , but after the component parts have been assembled.
  • a condensing boiler (not shown) is sited in a building, and a condensate drain pipe 10 leads from the boiler and through a hole 12 in a wall 14 of the building to the outdoors side of the wall.
  • a frost protection unit 16 has a housing 18 mounted indoors on or adjacent the wall 14 and the drain pipe 10 .
  • the housing 18 contains an electrical circuit including a power supply unit 20 which is fed with mains electricity via a thermal cut-out 22 .
  • the connections from the power supply unit 20 to the other components of the circuit are, for simplicity, not shown in the drawing.
  • a temperature sensor 24 (such as a thermistor or semiconductor sensor) is sited outside the building and is connected by a cable 26 passing through a further hole 28 in the wall 14 to the frost protection unit 16 .
  • the sensor 24 produces a signal dependent on the temperature T O outside the building, which is supplied to the inverting input of a differential amplifier 30 .
  • the differential amplifier 30 On its non-inverting input, the differential amplifier 30 receives a signal from a threshold temperature setting device 32 (such as a fixed resistor of a chosen value or a variable resistor) representing a threshold temperature T T .
  • the threshold temperature T T will be set to 5 Celsius.
  • the differential amplifier 30 also receives a signal from a gain setting device 34 (such as a fixed resistor of a chosen value or a variable resistor) representing a gain G 1 .
  • the current regulator 36 may regulate the output current I H by progressively varying the output current I H with progressive variations in the control voltage V C .
  • the current regulator 36 may pulse-width-modulate the output from the PSU 20 at a suitable frequency with a varying mark:space ratio so as to vary the short-term RMS value of the output current I H .
  • the latter option is preferred for reasons of efficiency.
  • a tee 38 is fitted into the drain pipe 10 adjacent the frost protection unit 16 .
  • Upstream and downstream portions 10 U, 10 D of the drain pipe 10 are connected to two of the limbs 38 A, 38 B of the tee 38 using conventional plumbing methods, and a flexible heater cable 40 enters the drain pipe 10 through a seal 42 in the other limb 38 C of the tee 38 .
  • the heater cable 40 passes along the downstream portion 10 D of the pipe 10 almost as far as its far end 10 E.
  • the heater cable 40 is a coaxial cable having a central resistive core 40 C of, for example, constantan, and a braided conductive shield 40 S of copper, with an intermediate insulator between the core 40 C and shield 40 S and an insulating sheath around the shield 40 S.
  • the core 40 C and shield 40 S are connected together.
  • the core 40 C and shield 40 S are connected to the cores of a two-core cable 44 which are connected at their opposite ends to the output from the current regulator 36 and to the electrical ground of the unit 16 .
  • the heater current I H therefore passes through the heater cable 40 .
  • the heating power H per unit length of the cable 40 is zero.
  • the values of G 2 , G 1 and ⁇ are chosen by trial and error so that the heating power H per unit length of the cable 40 is sufficient to prevent condensate in the drain pipe 10 freezing in all but the most extreme cold weather.
  • the heating power H per unit length of the cable is independent of the length of the heating cable 40 .
  • the heating cable 40 can therefore be cut in length, if desired, and have its cut end reconnected without it substantially affecting how hot the cable 40 will become.
  • the second embodiment of the invention is similar to the first embodiment described with reference to FIG. 1 , except in the following three respects.
  • the drain pipe 10 is connected to the condensate outlet of a freezer (not shown), rather than a boiler.
  • the sensor cable 26 does not pass through a separate hole 28 in the wall 14 . Instead it passes into the drain pipe 10 through the seal 42 of the fitting 38 and extends along the downstream portion 10 D of the pipe 10 to its far end 10 E where the temperature sensor 24 is disposed, sufficiently spaced from the heater cable 40 so that the sensor is substantially unaffected by heat from the heater cable 40 .
  • the sensor cable 26 could extend beyond the far end 10 E of the pipe 10 .
  • the current regulator 36 may employ amplitude modulation of the output current I H , or more preferably pulse-with modulation.
  • the third embodiment of the invention is similar to the second embodiment described with reference to FIG. 2 , except in the following four respects.
  • the drain pipe 10 is connected to the condensate outlet of an air conditioning unit (not shown), rather than a freezer.
  • the sensor cable 26 does not extend to the far end 10 E of the drain pipe 10 , but instead exits from the drain pipe 10 through a seal 42 at a second tee 46 immediately on the outdoors side of the wall 14 .
  • the second tee 46 is similar to the first tee 38 , but the seal 42 is provided in one of the aligned limbs 46 A of the tee 46 , and the portions of the drain pipe 10 are connected to the other two right-angled limbs 46 B,C of the tee 46 .
  • the sensor 24 may be mounted on the wall 14 adjacent the tee 46 .
  • a voltage regulator 48 is employed in place of the current regulator 36 of FIG. 2 .
  • voltage regulator 48 may employ amplitude modulation of the output voltage V H and therefore of the output current I H , or more preferably pulse-with modulation.
  • the heating power H per unit length of the cable is not independent of the length of the cable 40 , but instead is inversely proportional to the square of the length L of the cable 40 . Therefore, if the heating cable 40 is cut in length, it may become excessively hot in use. To prevent this, the voltage regulator 48 has an upper limit on its output current TH set by a current limit setting device 50 (such as a fixed resistor).
  • the tee 38 and seal 42 shown in FIG. 1 are shown in greater detail in FIGS. 4A-C .
  • the tee 38 is of conventional form.
  • the seal 42 for the tee 38 is provided by a resilient tapered bung 52 having a central hole 54 for the heater cable 40 and a slit 56 extending from the hole 54 to the edge of the bung 52 to enable the bung 52 to be forced sideways onto the cable 40 .
  • the slit 56 closes up and the bung 52 is compressed between the cable 40 and the socket 58 to seal the cable 40 to the tee 38 .
  • FIGS. 5A-C An alternative tee 38 and seal 42 are shown in FIGS. 5A-C .
  • the seal 42 is in the form of a squash gland having a resilient annular gland member 60 and a gland nut 62 .
  • the limb 38 C of the tee 38 has a cavity 64 and an internal thread 66 to form the housing for the squash gland.
  • the gland member 60 and nut 62 are slid along the heater cable 40 to the required position.
  • the gland member 60 is inserted into the cavity 64 and the nut 62 is screwed into the gland housing so as to compress the gland member 60 so that it seals with the cable 40 and the tee 38 .
  • the gland member 60 may be slit, similarly to the bung 52 of FIGS. 4A-C , so that it can be fitted sideways onto the cable 40 .
  • the tee 38 and seal 42 shown in FIG. 2 are shown in greater detail in FIGS. 6A-C .
  • the seal 42 is provided by a bung 68 similar to the bung 52 of FIGS. 4A-C , except that the bung 68 has two holes 70 , 72 for the heater cable 40 and sensor cable 26 , respectively, a slit 74 extending between the holes 70 , 72 and from the hole 70 to the edge of the bung 68 to enable the hung 52 to be forced sideways onto both cables 40 , 26 .
  • FIG. 7 shows an alternative fitting 74 for sealing the heater cable 40 to the drain pipe 10 .
  • the fitting 74 is generally in the form of a moulded plastics straight coupler having sockets 74 A,B for connecting the upstream and downstream portions 10 U,D of the pipe 10 .
  • inner and outer contacts 76 I,O of a phono plug are connected to the core and shield 40 C,S of the cable 40 and are moulded into a bulge 74 C in the wall of the fitting 74 during moulding of the fitting 74 so as to form a phono plug 76 projecting from the wall of the fitting 74 .
  • the end of the cable 44 from the frost protection unit 16 is fitted with a complementary phono line socket 78 which is connected to the phono plug 76 . Similar principles may be employed for connecting the sensor cable 26 through the wall of the pipe 10 , and for connecting both the heater cable 40 and the sensor cable 26 through the wall of the pipe at the same fitting.
  • FIG. 8 shows an alternative method of sealing the heater cable 40 (or sensor cable 26 ) to the drain pipe 10 .
  • a hole 80 is drilled through the wall of the pipe 10 .
  • the cable 40 , 26 is then threaded through the hole to the required position.
  • a bead 82 of room-temperature-vulcanizing (RTV) silicone rubber is then applied around the cable 40 , 26 and allowed to cure so as to seal the cable 40 , 26 to the pipe 10 .
  • RTV room-temperature-vulcanizing
  • a bead 82 of rubber or the like is intended to be covered by the term “fitting”.
  • FIGS. 9 and 10 show a further fitting and arrangement of condensate drain pipe.
  • the fitting includes a conventional 22 mm equal tee 38 and a reducer 84 , both of rigid plastics material.
  • the 22 mm upstream portion 10 U of the condensate drain pipe, leading from a boiler, is of rigid plastics material which is solvent-welded into the central limb 38 A of the tee 38 .
  • the reducer 84 is moulded from plastics material and has a flange portion 86 which is a snug fit in the lower limb 38 D of the tee 38 and a downwardly-projecting spigot portion 88 to which the upper end of a length of flexible polythene hose 10 H is fitted.
  • the hose 10 H runs through a further 22 mm pipe 90 of rigid plastics material which may have various elbows and couplers (not shown) and which passes through the wall of the building (not shown) from the inside to the outside.
  • the upper end of the further pipe 90 is solvent-welded into the lower limb 38 D of the tee 38 after the reducer 84 has been fitted.
  • the connection between the heater cable 40 and its supply cable 44 is moulded into a bung 42 which is solvent-welded into the upper limb 38 C of the tee 38 .
  • the heater cable 40 therefore extends from the bung 42 , through the tee 38 and spigot portion 88 of the reducer 84 and then runs along the inside of the hose 10 H so that the distal end 40 D of the heater cable 40 is adjacent the distal end 10 E of the hose 10 H.
  • the cross-sectional diameter of the heater cable 40 is substantially less than the inner diameter of the spigot portion 88 of the reducer 84 and the inner diameter of the hose 10 H so that condensate from the boiler can flow from the upper portion 10 U of the condensate drain pipe 10 U, through the tee 38 , spigot portion 88 and hose 10 H, to the open distal end 10 E of the hose 10 H.
  • the hose 10 H therefore forms the downstream portion of the condensate drain pipe.
  • the hose 10 H is preferably provided as one continuous length so that, outside the building, there are no joints or very sharp bends in the hose 10 H to promote the seeding of ice crystals. Also, the provision of two layers material (i.e.
  • the further pipe 90 provides physical protection for the flexible hose 10 H.
  • the sensor 24 and sensor cable 26 are not shown in FIGS. 9 and 10 .
  • the sensor cable 26 may be routed to the outside of the building independently of the condensate drain pipe, as in FIG. 1 , or it may be fed through the hose 10 H as in FIGS. 2 and 3 , or it may be fed through the air gap 92 between the hose 10 H and the further pipe 90 .
  • the amplifier 30 may have a transfer function other than linear or square root.
  • any of the embodiments described above may be modified to employ the method of any of the other embodiments (i) of connecting the heater cable 40 to its supply cable 44 , (ii) of passing the heater cable 40 and/or supply cable 44 from the outside to the inside of the condensate drain pipe 10 ; and (iii) of passing the sensor cable between the outside and the inside of the condensate drain pipe 10 .

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Pipe Accessories (AREA)
  • Sink And Installation For Waste Water (AREA)
US13/021,095 2010-02-08 2011-02-04 Frost protection system for condensate drain pipe Abandoned US20110192180A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GBGB1001999.0 2010-02-08
GBGB1001999.0A GB201001999D0 (en) 2010-02-08 2010-02-08 Frost protection system for condensate drain pipe
GB1014462A GB2470519A (en) 2010-02-08 2010-09-01 Frost protection system for a condensate drain pipe
GBGB1014462.4 2010-09-01

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US9353993B2 (en) 2012-06-07 2016-05-31 Carrier Corporation Condensate trap heater for condensing gas furnace
CN109506369A (zh) * 2018-10-23 2019-03-22 珠海格力电器股份有限公司 一种排水装置、其控制方法及壁挂炉
US10502454B2 (en) * 2016-08-01 2019-12-10 Johnson Controls Technology Company Furnace for a rooftop unit
US11187435B2 (en) * 2019-07-01 2021-11-30 Intellihot, Inc. Heated condensate drainage tube
US20230094240A1 (en) * 2021-09-30 2023-03-30 Midea Group Co., Ltd. Method and Apparatus for a Drain Harness
KR102660764B1 (ko) * 2023-02-02 2024-04-26 주식회사 비쏠시스템 공기조화기용 실외기의 배수 결빙 방지 장치

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GB2489425A (en) * 2011-03-25 2012-10-03 Adey Holdings 2008 Ltd Preventing freezing in a boiler condensate drain pipe
ITTO20130169U1 (it) * 2013-11-14 2015-05-15 Indesit Co Spa Apparecchio di refrigerazione, in particolare di uso domestico, di tipologia migliorata
CN104197472B (zh) * 2014-09-19 2017-01-11 珠海格力电器股份有限公司 一种除湿机内动力装置的控制方法及系统
EP3214253B1 (fr) * 2016-03-03 2019-07-10 Skaala IFN Oy Dispositif de ventilation pour une fenêtre
DE102022126167A1 (de) * 2022-10-10 2024-04-11 Vaillant Gmbh Kondensatabführvorrichtung und Wärmepumpe

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US4790375A (en) * 1987-11-23 1988-12-13 Ors Development Corporation Mineral well heating systems
US5218185A (en) * 1989-08-15 1993-06-08 Trustees Of The Thomas A. D. Gross 1988 Revocable Trust Elimination of potentially harmful electrical and magnetic fields from electric blankets and other electrical appliances
US5633978A (en) * 1994-02-17 1997-05-27 Hofsaess; Marcel Electrical immersion heater with removable self-supporting carrier and housing
US6269876B1 (en) * 1998-03-06 2001-08-07 Shell Oil Company Electrical heater
EP1498712A1 (fr) * 2003-07-14 2005-01-19 Aos Holding Company Ensemble détecteur de température, chauffe-eau comportant un tel ensemble, et méthode pour détecter la température
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9353993B2 (en) 2012-06-07 2016-05-31 Carrier Corporation Condensate trap heater for condensing gas furnace
US10502454B2 (en) * 2016-08-01 2019-12-10 Johnson Controls Technology Company Furnace for a rooftop unit
US11486604B2 (en) 2016-08-01 2022-11-01 Johnson Controls Tyco IP Holdings LLP Furnace for a rooftop unit
CN109506369A (zh) * 2018-10-23 2019-03-22 珠海格力电器股份有限公司 一种排水装置、其控制方法及壁挂炉
US11187435B2 (en) * 2019-07-01 2021-11-30 Intellihot, Inc. Heated condensate drainage tube
US20230094240A1 (en) * 2021-09-30 2023-03-30 Midea Group Co., Ltd. Method and Apparatus for a Drain Harness
US11885555B2 (en) * 2021-09-30 2024-01-30 Midea Group Co., Ltd. Method and apparatus for a drain harness
KR102660764B1 (ko) * 2023-02-02 2024-04-26 주식회사 비쏠시스템 공기조화기용 실외기의 배수 결빙 방지 장치

Also Published As

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EP2354694A2 (fr) 2011-08-10
GB201001999D0 (en) 2010-03-24
EP2354694A3 (fr) 2011-12-21
GB201014462D0 (en) 2010-10-13
GB2470519A (en) 2010-11-24

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