EP0914580B1 - Water heater made of plastic, in particular pressurized water heater - Google Patents

Water heater made of plastic, in particular pressurized water heater Download PDF

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Publication number
EP0914580B1
EP0914580B1 EP97935750A EP97935750A EP0914580B1 EP 0914580 B1 EP0914580 B1 EP 0914580B1 EP 97935750 A EP97935750 A EP 97935750A EP 97935750 A EP97935750 A EP 97935750A EP 0914580 B1 EP0914580 B1 EP 0914580B1
Authority
EP
European Patent Office
Prior art keywords
water heater
water tank
materials
agents
blends
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.)
Expired - Lifetime
Application number
EP97935750A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0914580A1 (en
Inventor
Vladimiro Stopponi
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.)
Merloni Termosanitari SpA
Original Assignee
Merloni Termosanitari SpA
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Filing date
Publication date
Application filed by Merloni Termosanitari SpA filed Critical Merloni Termosanitari SpA
Publication of EP0914580A1 publication Critical patent/EP0914580A1/en
Application granted granted Critical
Publication of EP0914580B1 publication Critical patent/EP0914580B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • F24H9/40—Arrangements for preventing corrosion
    • F24H9/45—Arrangements for preventing corrosion for preventing galvanic corrosion, e.g. cathodic or electrolytic means
    • F24H9/455—Arrangements for preventing corrosion for preventing galvanic corrosion, e.g. cathodic or electrolytic means for water 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
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/18—Water-storage heaters
    • F24H1/181—Construction of the tank
    • 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
    • F24H9/40—Arrangements for preventing corrosion
    • F24H9/45—Arrangements for preventing corrosion for preventing galvanic corrosion, e.g. cathodic or electrolytic means
    • 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
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/18—Water-storage heaters
    • F24H1/20—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes
    • F24H1/201—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes using electric energy supply
    • F24H1/202—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes using electric energy supply with resistances

Definitions

  • the invention relates to a water heater apparatus made of plastic material, in particular, though not exclusively, used as a pressurised water heater and tank.
  • the apparatus is entirely made of plastic material.
  • the various parts are assembled by means of welding and are thereafter coated to render the internal parts rust-resistant and give the apparatus a necessarily long working life.
  • Low-alloy steel heaters use magnesium-based changeable elements which are substituted, during the corrosion process, for the steel components of the apparatus.
  • the main drawbacks essentially relate to the steel materials used in making the product, which do not always correspond to the fixed specifications, to the protective coatings applied and to the variability of the conditions of the technological processes used during the various phases of the manufacturing process.
  • electric hot-water tanks for example those made with low-alloy carbon steel tanks, comprise an autoclave flange group housing an electric resistance element, having a potential which correlates to the volume and use of the apparatus, and the inlet and outlet pipes; a system of outside covering constituted by polypropylene shells filled with CaCo 3 whose primary function is aesthetic (the area between the tank and the external shell is usually filled with semi-rigid polyurethane foam acting as a heat insulation and, to a limited extent, as internal supports for the PP shells, which in any case are not subject to any particular stress during use; (the autoclave flange, apart from the electrical resistance element, also supports a thermostatic system and a sacrificial element basically made of magnesium (Mg), which acts as a rust safeguard, within certain limits, for the internal parts of the boiler (the boiler is advantageously coated at 15-40 ⁇ with heat -hardening glazes - in some cases, in longer-duration heaters, the internal surface of the boiler is glaze-p
  • thermoplastics normally, it is not possible to melt and mix together different thermoplastic species in order to obtain a new material from the blend.
  • the not mixable materials are incompatible each other.
  • Many additives have been developed that render compatible, i. e. mixable in a homogenous blend, different materials but they are to be prepared specifically for each couple or group of materials to compatibilize so that it is practically impossible to utilise this technology for the recycling of generic and not well known thermoplastics.
  • EP 0 674 139 represents a remarkable progress since it discloses how to build a water heater structure using a unique material as for the tank as for the insulating protection and the outer envelope. So an easy recovery and recycling of the water heater structure is realistically possible but there is the drawback that the chosen unique material obliges necessarily, in general, to a compromise which does not allow the selection of the best plastic material for each of the various and very different functions to be assured to each one of the water heater components.
  • thermoplastic materials especially suited to recycling operations.
  • high-density polythene obtained through a low-pressure polymerisation of ethylene
  • its hot-welding characteristics have led to faster water pipe-laying and have helped to reduce the need for expensive and frequent maintenance checks on the pipes.
  • the research at the foundation of what is proposed in the present invention relates to the search for basic characteristics, from the mechanical point of view, which are sufficiently high-quality and long-lasting (within certain limits) under average pressure conditions (corresponding to the pressure of the municipal water supply) and under maximum temperature conditions reached during the heating of water inside domestic water tanks, under a normal filling/emptying regime.
  • a further aim of the invention is to satisfy the utility characteristics of the basic thermoplastic materials as well as the additional alloy components and accessories from a hygienic point of view, thus the invention will meet the international hygienic requirements on organic and inorganic migration in relation to toxic or pollutant characteristics.
  • a further important objective of the present invention is that the component parts should be entirely recyclable, as prescribed in the existing legislative dispositions and surely in future ones (probably getting progressively tighter and more stringent).
  • a still further aim of the present invention is to obtain high reliability over long time periods - already the market is demanding five year guarantees or longer.
  • the aims as set out above highlight problems which have caused real obstacles to the manufacture of apparatus responding to all the demands being made.
  • thermoplastic materials to substitute metals.
  • film-forming resins too, based on 12-carbon -atom polyamides (PA) as internal rust-protection coatings have produced only poor results, whether due to the presence of water-absorbing characteristics on the part of polyamide resins, or following on from this phenomenon, due to the formation of blisters leading over time the corrosion thanks to the damp getting under the film-coating itself.
  • PA 12-carbon -atom polyamides
  • the invention provides a new water heater, offering various boiler volumes (for example, from 5 to 100 litres), made of techno-polymer plastic materials having utilizable shapes, wherein the choice of thermoplastic materials, their shaping and structural design, coherent with the characteristics of the thermoplastic material, give the boiler adequate resistance to repeated P/T cycles on values up to 8 bars and 95° C and increase its resistance to aging to at least 5 years.
  • the invention relates to a water heating apparatus made of plastic material, in particular a pressurised water heater comprising a water tank made of thermoplastic polymer material, insulation arranged externally to said tank, made of material which is or which has been made compatible to the water tank, and a shell which is external of said insulation.
  • Said external shell can also be made of a material compatible with the water tank, in the case of smaller volume tanks, while for larger tanks it could be made of traditional materials.
  • the water tank can be made of polyolefin, polymer and copolymer materials, based on styrol and/or butadiene and/or acrylates, polyamides, polyphenylethyls, polyethylsulfone and polysulfone resins or blends thereof, or polymeric mixtures thereof.
  • a reinforcing agent or filler can be added to the material used to make the water tank, at a percentage comprised between 10 and 40%, preferably between 20 and 30%, with the aim of improving the mechanical characteristics and the size stability.
  • reinforcing agent glass fibre or spheres can be used, while talcum might be used as a filler material, or calcium carbonate or mica. Obviously reinforcing materials can be used in combination with fillers.
  • coupling agents Other materials, known as coupling agents, can be added, for improving the reinforcement and filler adhesion to the polymers or mixtures.
  • compatiblizing agents or mixtures thereof can be added to improve polymer cohesion. These agents can also be used for the insulating material and/or for the external shell.
  • nucleation agents can be used, optimised for the purpose, for crystalline materials.
  • Antistatic agents can also be added, as can anti-UV agents, fireproof materials, colorants and lubricants.
  • stabilising agents of various nature and composition can be added, to reduce time-induced changes in the polymer characteristics.
  • the boiler water tank of the invention can be made by pressing, injection or blow-moulding.
  • the water tank can be made in two or more partial shells, welded together, for example by heat welding or by press-fitting, or gluing.
  • the external shell can be made, according to the invention, separately with respect to the insulation, or as an external skin or "crust" of the insulation.
  • Figure 1 shows a prior-art water heater 1 having a metal water tank 2 containing the resistance 3 and the sacrificial anode 4.
  • Insulation 5 is arranged externally of the water tank 2, closed by an external shell 6 made of plastic.
  • the water heater 11 of figure 2 exhibits a water tank 12 made of polymer thermoplastic material made in two halves, joined together in the example by means of heat welding.
  • the insulation 13, made of a material which is compatible or compatiblized with the material used for the water tank 12 (with the aim of avoiding any recycling problems of the water heater 11 at the end of its working life), is arranged externally of the water tank 12.
  • the external shell 16 is also made of a material which is compatible or compatiblized with that of the water tank 12.
  • the resistance 14 and the thermostat shield 15 are inside the water tank 12.
  • thermoplastic materials used as primary matrix various fillers and reinforcements can be added, namely crystallisation-control additives, dimensional stability and thermal and mechanical phenomena agents (including those phenomena connected with internal stress during the formation process), and oxidation stabilizers. All of these can improve the duration of the matrix material over quite long time periods.
  • Modifying additives can also be used, for chancing viscosity properties and in general rheological properties, ensuring a better workability in the pressing of the pieces, all with the aim of obtaining regular shapes and breadths.
  • the boiler body 12 is to be obtained through injection-molding, one of the most common technologies, not only for thermoplastic materials but also for elastomers and thermosetting materials, the water tank 12 is made in one or two parts and welded using methods largely experimented during the development of the present invention.
  • the water tank 12 can also be obtained using pressing methods known as blow-molding, with one or more layers, which as the advantage that a better regulation of the breadth of the hollow body walls can be achieved, which walls constitute the water tank itself, thanks to the movable central nucleus of blowing heads and special mold geometries.
  • blow-molding with one or more layers, which as the advantage that a better regulation of the breadth of the hollow body walls can be achieved, which walls constitute the water tank itself, thanks to the movable central nucleus of blowing heads and special mold geometries.
  • FCKW foam plastic with vacuum elements.
  • This process is difficult to apply in the case of water heaters.
  • new techniques and materials have replaced PUR based products, for reasons of recyclability at the end of the heaters' working life, and pains have been taken to avoid mixing in with the recyclable materials others which are not so.
  • the insulation 13 of the heater is constituted by pressed shells made of chemically-foamed thermoplastic material, not damaging to the environment and having a density which is similar to that of PUR.
  • the apparatus obtained according to the invention in particular related to the use of chemically-foamed polyolefin produced by heat-pressing, can have, instead of the external shells, obtained by injection-molding of polypropylene resins filled with CaCo 3 , a heat-forming process with thermoplastic sheets, contemporaneous to the formation of the foamed insulating shells.
  • the water tank will be coated with two or more shells made off foamed material having an external surface constituted by a "skin" derived from the forming and perfect adhesion of the foam to a sheet, whose material will be homogeneous or compatible with the material constituting the boiler and the insulation.
  • a boiler of the breadth of 15 to 25 mm can be made, with a a creep factor so contained as to guarantee aqueduct-level pressure resistance and to function at working temperature for 5 years.
  • the boiler can be made in two shells, obtained by injection molding and simply welded together by rotary heat pressing, or the boiler can be obtained in a single piece by blow molding.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Pump Type And Storage Water Heaters (AREA)
  • Details Of Fluid Heaters (AREA)
  • Cookers (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
EP97935750A 1996-07-26 1997-07-24 Water heater made of plastic, in particular pressurized water heater Expired - Lifetime EP0914580B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
IT96RM000532A IT1284232B1 (it) 1996-07-26 1996-07-26 Apparecchio scalda acqua in materilae plastico in particolare scalda acqua ad accumulo e pressione
ITRM960532 1996-07-26
PCT/IT1997/000186 WO1998004873A1 (en) 1996-07-26 1997-07-24 A water heater apparatus made of plastic, in particular a pressurized water heater tank

Publications (2)

Publication Number Publication Date
EP0914580A1 EP0914580A1 (en) 1999-05-12
EP0914580B1 true EP0914580B1 (en) 2002-04-10

Family

ID=11404363

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97935750A Expired - Lifetime EP0914580B1 (en) 1996-07-26 1997-07-24 Water heater made of plastic, in particular pressurized water heater

Country Status (7)

Country Link
EP (1) EP0914580B1 (es)
CN (1) CN1112549C (es)
AU (1) AU3863197A (es)
DE (1) DE19781958T1 (es)
ES (1) ES2169644B2 (es)
IT (1) IT1284232B1 (es)
WO (1) WO1998004873A1 (es)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1297428B1 (it) * 1997-12-29 1999-12-17 Merloni Termosanitari Spa Scaldaacqua di materiale plastico resistente a pressione
IT1310186B1 (it) * 1999-03-09 2002-02-11 Merloni Termosanitari Spa Scaldaacqua elettrico o a gas con un elemento di rivestimentoparzialmente avvolgente e smontabile.
DE202010001010U1 (de) 2010-01-16 2011-05-26 CONSOLAR Solare Energiesysteme GmbH, 60489 Druckbelastbarer Speicher
KR101874069B1 (ko) * 2013-11-29 2018-07-03 김노을 플라스틱 온수 보일러
EP3687960B1 (en) * 2017-09-28 2024-03-20 Carboclave Corp. Displaced air carbonation (dac) process and system
WO2022229477A1 (es) * 2021-04-28 2022-11-03 Inerox Industries Sl Depósito acumulador de agua caliente a presión de material plástico y calentador eléctrico

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2548954B1 (fr) * 1983-07-12 1986-03-21 Nusbaumer Charles Procede pour realiser une enceinte etanche
EP0134363A3 (en) * 1983-09-13 1985-11-13 Everlast Hot Water Systems (Proprietary) Limited Container for use as a pressure vessel in a hot water system
FR2620803B1 (fr) * 1987-09-21 1990-01-12 Chaffoteaux Et Maury Perfectionnements aux ballons d'eau chaude
DE4410215A1 (de) * 1994-03-24 1995-09-28 Bosch Gmbh Robert Raumwasserspeicher, insbesondere Elektro-Kleinspeicher

Also Published As

Publication number Publication date
ITRM960532A0 (es) 1996-07-26
IT1284232B1 (it) 1998-05-14
ITRM960532A1 (it) 1998-01-26
CN1112549C (zh) 2003-06-25
DE19781958T1 (de) 1999-08-12
WO1998004873A1 (en) 1998-02-05
ES2169644B2 (es) 2003-12-01
CN1229465A (zh) 1999-09-22
EP0914580A1 (en) 1999-05-12
ES2169644A1 (es) 2002-07-01
AU3863197A (en) 1998-02-20

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