EP0668984B1

EP0668984B1 - Self-supporting water heater, adapted to be made of plastic material

Info

Publication number: EP0668984B1
Application number: EP94926228A
Authority: EP
Inventors: Romano Nardi
Original assignee: Nardi Tecnologie Srl
Current assignee: Nardi Tecnologie Srl
Priority date: 1993-09-17
Filing date: 1994-09-01
Publication date: 1997-12-29
Anticipated expiration: 2014-09-01
Also published as: BR9405595A; ITTO930684A0; ATE161619T1; AU7614994A; EP0668984A1; ITTO930684A1; DE69407562D1; IT1261870B; WO1995008085A1

Abstract

Self-bearing water heater composed of a first internal container (1) made of plastic material, a second external container (3) made of plastic material in which the first container (1) is placed after having inserted suitable insulating material (5); the first container (1) being shaped as a parallelepiped, with rectangular section, with the two greater faces (7) crossed and connected by a plurality of hollow ducts (9) perpendicular to the faces (7), running from one face to the other, with notches (11) in the faces (7) next to the ducts (9), the faces (7) furrowed by a plurality of perpendicular external grooves (13) intersecting the notches (11), running as a ring on the periphery of the body (1) section and composing, with the ducts (9), the container rib (1); on the smaller (15) and greater faces (7) of the body (1) being provided a plurality of support projections (17) between internal container (1) and external container (3).

Description

The present invention deals with a self-bearing water heater, adapted to be made of plastic material.
It is well known how currently commercially available water heaters, made of sheet, galvanized and/or enameled, are generally composed of a cylindrical body, vertically placed, above and below which respective caps are applied, that are slightly crowned to complete the body. This is for water heaters of greater sizes to be used in bathrooms.
Lower sized water heaters, the so-called "quick" or "semi-quick" ones, are also of a circular shape, placed horizontally instead of vertically given their different capacity, but they are always made of treated sheet and composed of a cylindrical body closed by caps.
These water heaters, whether vertical or horizontal ones, therefore have fundamentally the same composition: a central body and two covering caps welded thereto, this shape being compulsory to obtain the operating pressure.
FR-A-2 479 429, that is deemed as the most relevant prior art, discloses a heat accumulator comprising a first, or internal container made of synthetic material and a second, or external, insulating container whose internal contour corresponds to the external shape of the first, internal container and that is stiffly placed around it.
The major inconveniences related to these water heaters are mainly due to workings to produce them: pressing and/or rolling the galvanized or anyway treated sheet to obtaing single bodies, welding thereof, control thereof, enamelling, and finally insertion of necessary members for their operation like resistance, thermostat, valves and anything else needed.
In addition to these inconveniences, there are the typical ones related to an object made of sheet that contains water, such as corrosion, foulings, welding, ageing and so on.
Object of the present invention is to solve the above inconveniences, providing a simple and practical water heater, of a particular shape, made of suitable plastic material, that among other things provides the following advantages:

it is lighter, about 65% less in weight;
it is produced with about 75% less labour;
raw materials and components, though being special and safer, cost at least 20% less;
packagings and transport cost at least 1/3 less, due both to lower weight and to lower volume;
it is free from corrosion so that, in addition to a better hygiene, it lasts abundantly more than traditional water heaters;
it consumes less current because it is more efficiently insulated;
given the provided shape, it can also be installed inside a piece of furniture.

These, together with other objects and advantages that will be apparent from the following description, are achieved with a water heater as claimed in Claim 1.
A further major characteristic of the water heater of the invention is that on the shorter bottom face of the first container, there are assembled, in addition to the typical water heater elements like resistance and outlet pipe for hot water, a safety valve and a pressure reducer, the latter one being adapted to reduce pressure inside the container and to avoid possible water hammers, with clear, obvious benefits for water heater operation and life, under maximum safety conditions.
A further characteristic of the water heater of the invention is that said hollow "pulling ducts", running perpendicular to the wider container faces, are adapted to make mechanical members pass through them, like tie rods and/or bolts to secure the container itself to the wall or for other purposes, some of which are specified below.
According to a first embodiment, the internal container is obtained in a single piece in suitable plastic material, such as polyethylene or polypropylene; the external container being made of ABS and the insulating material being foamed polyurethan.
According to a second embodiment, the internal container made of suitable plastic material, like polyethylene or polypropylene, is obtained in two pieces, or opposed shells, joined together making their respective edges and the "pulling ducts" of each shell mate; sealing of said two shells being obtained adequately shaping said edges to allow a suitable matching thereof, downstream of which a gasket is provided running for the whole container periphery, and joining together with suitable securing means or bolts said edges, and, with suitable gaskets, the "pulling ducts" of each shell; the external container being made of ABS and the insulating material being foamed polyurethan.
It is obvious that both the first and the second embodiment can be obtained through injection molding, vacuum molding, or by blowing suitable plastic material.
The invention will now be described in detail with particular refernce to the enclosed drawings that show some preferred embodiments of the invention, in which:

Figure 1 is a front elevation view of the internal container of the water heater of the invention, with the external container in section;
Figure 2 is a side elevation view of the internal container of the water heater, with the external container in section;
Figure 3 is a section made along line III-III in Fig. 2;
Figure 4 is a section made along line IV-IV in Fig. 1;
Figure 5 is an external front view of the water heater of the invention;
Figure 6 is a front view of the internal container sorrounded by a stiffening tape network system;
Figure 7 is a front elevation view of a second embodiment of the internal container;
Figure 8 is a section made along line VIII-VIII in Fig. 7;
Figure 9 is a partially enlarged view of the edge junction.

As clearly appears from the figures, the water heater of the invention is substantially composed of: a first, or internal container 1 made of suitable plastic material and a second, or external container 3 also made of suitable plastic material in which the first, or internal container 1 is placed after having inserted suitable insulating material 5 between the two containers 1 and 3.
The first container 1 is shaped as a parallelepiped, with rectangular section, where the two greater faces 7 (front and rear ones) are crossed and connected by a plurality of hollow ducts 9 perpendicular to said faces 7, running as tie rods from one face to the other.
A plurality of notches 11 is provided in each face 7 next to each duct 9. Said faces 7 are furrowed by a plurality of external grooves 13 perpendicular to the sides and intersecting said notches 11, running as a ring on the whole periphery of the body 1 section and composing, with the above pulling ducts 9, the container 1 rib.
On the smaller faces 7 and greater faces 15 of the parallelepiped 1 there is provided a plurality of projections 17 operating as support between internal container 1 and external container 3.
The second container 3 is shaped as a parallelepiped, with rectangular section, adequately thick, adapted to house the first container 1 inside it; the clearance provided between said first and said second container being, as already said, adequately filled with insulating material 5, like foamed plastic material.
On the shorter bottom face 15 of the first container 1, there are assembled, in addition to the typical water heater elements like resistance 19 and outlet pipe 21 for hot water, a safety valve 23 and a pressure reducer 25, the latter one being adapted to reduce pressure inside the container and to avoid possible water hammers, with clear, obvious advantages for water heater operation and life.
A temperature gauge 27 is provided on a (front) face 29 of the second container 3.
It must be noted that the hollow pulling ducts 9, running perpendicular to the wider faces 7 of the container 1, are adapted to make mechanical members pass through them, like tie rods and/or bolts to secure the container itself to the wall or for other purposes, some of which will be specified below.
According to a first embodiment, the internal container is obtained in a single piece in suitable plastic material, such as polyethylene or polypropylene; the external container being preferably made of ABS and the insulating material being preferably foamed polyurethan.
According to a second embodiment, the internal container made of suitable plastic material, like polyethylene or polypropylene, is obtained in two pieces 31, or opposed shells, joined together making their respective edges 33 and the "pulling ducts" 35 of each shell mate; sealing of said two shells 31 being obtained adequately shaping said edges 33 to allow a suitable matching thereof, downstream of which a gasket 37 is provided running for the whole container periphery, and joining with suitable securing means or bolts 39 said edges 33, and, with suitable gaskets, the "pulling ducts" 35 of each shell.
Both the first and the second embodiment can be obtained through injection molding with shell die, vacuum molding, or further by blowing suitable plastic material.
It is obvious that also for the second mentioned embodiment, the plastic material preferably used for the second container 3 is ABS and the insulating material 5 provided in the hollow space between first container 1 and second container 3 is preferably foamed polyurethan.
The internal and external containers can be realized through other production techniques that are typical of the wide range of available plastic materials.
The internal container 1 is designed in a suitable plastic material with such thickness as to guarantee an easy and safe operation under the various recurring operating conditions; however, for greater safety, a further safety element is provided applied to said internal container 1; this element is composed of a fencing with tapes 41, strap-type, running along the external grooves of the container itself and creating a network element around it. Said tapes 41 are adequately joined together, for example through bolts 43 or the like.

Claims

Self-bearing water heater composed of:
- a first internal container (1) made of plastic material;

- a second external container (3) also made of plastic material in which the first internal container (1) is placed,
characterized in that:
- the first container (1) is shaped as a parallelepiped, with rectangular section, whose two greater faces (7), front and rear ones, are crossed and connected by a plurality of hollow ducts (9) perpendicular to said faces (7), running as tie rods from one face to the other, a plurality of notches (11) being provided in each face (7) next to each duct (9), said faces (7) being furrowed by a plurality of external grooves (13) perpendicular to the sides and intersecting said notches (11), running as a ring on the whole periphery of the section of said first container (1) and composing, with said pulling ducts (9), the rib of said first container (1), on the smaller (15) and greater faces (7) of said container (1) being provided a plurality of projections (17) operating as support between said first internal container (1) and said second external container (3),

- the second container (3) is shaped as a parallelepiped, with rectangular section, adapted to house the first container (1) inside it, a clearance provided between said first container (1) and said second container (3) being filled with insulating material (5), like foamed plastic material.
Self-bearing water heater according to claim 1, characterized in that on the shorter bottom face (15) of said first container (1), there are assembled, in addition to other water heater elements like a resistance (19) and an outlet pipe (21) for hot water, a safety valve (23) and a pressure reducer (25), the latter one being adapted to reduce pressure inside said first container (1) and to avoid possible water hammers.
Self-bearing water heater according to claim 1, characterized in that said hollow pulling ducts (9), running perpendicular to the wider faces (7) of said first container (1), are adapted to make mechanical members pass through them, like tie rods and/or bolts, to secure said first container itself to the wall.
Self-bearing water heater according to any of the previous claims, characterized in that said internal container (1) is obtained in a single piece of plastic material, such as polyethylene or polypropylene; said external container (3) being made of ABS and said insulating material (5) being foamed polyurethane.
Self-bearing water heater according to any one of claims 1 to 3, characterized in that said internal container (1) made of plastic material, like polyethylene or polypropylene, is obtained in two pieces, or opposed shells (31), joined together making their respective edges (33) and "pulling ducts" (35) of each shell (31) mate, sealing of said two shells (31) being obtained shaping said edges (33) to allow a matching thereof, downstream of which a gasket (37) is provided running for the whole container periphery, and joining with securing means or bolts (39) said edges (33), and, using gaskets, said "pulling ducts" (35) of each shell (31), said external container (3) being made of ABS and said insulating material (5) being foamed polyurethane.
Self-bearing water heater according to any of the previous claims, characterized in that said internal container (1) is obtained through injection molding, vacuum molding, or by blowing plastic material.
Self-bearing water heater according to any of the previous claims, characterized in that said external container (3) made of plastic material like ABS, is obtained through common molding techniques for said material.
Self-bearing water heater according to any of the previous claims, characterized in that a safety element is provided applied to said internal container (1) that is composed of a fencing with tapes (41), strap-type, running along external grooves of said internal container (1) itself and creating a network element around it.