EP3242094B1

EP3242094B1 - Boiler with predetermined dimensions, but suitable for containing heat exchangers with different dimensions

Info

Publication number: EP3242094B1
Application number: EP16168181.2A
Authority: EP
Inventors: Daniele Aleardi
Original assignee: A-Steel Srl
Current assignee: A-Steel Srl
Priority date: 2016-05-03
Filing date: 2016-05-03
Publication date: 2019-05-01
Anticipated expiration: 2036-05-03
Also published as: PL3242094T3; EP3242094A1; ES2738409T3

Description

The present invention relates to a boiler for heating rooms and producing sanitary water, according to the preamble of the main claim.
A boiler of the type mentioned above comprises a tubular cylindrical body (or ferrule or external shell) and end and opposed closing elements (or end plate). Inside such body there is placed a heat exchanger or (single or concentric spiral) coil through which water flows, said heat exchanger being usually placed in correspondence with a gas burner; for instance, such burner is arranged coaxially within the coil or tube nest of the heat exchanger. The water that flows through the latter is heated by the flame generated by the burner and/or by the smokes that generate in the boiler (or better, in a combustion chamber thereof which contains the coil and the burner) as a result of the operation of the burner.
In the traditional boilers of the type indicated above, the heating power also depends on the quantity of water that flows through the tube nest or coil. Note that the latter can be a single tube or a double tube one, one tube being inserted in the other.
Therefore, a mode to increase such power is that of modifying the dimensions of the individual turns of such tube nest as measured orthogonally to its own longitudinal axis. In other words, in such mode coils are used with different outer diameters, the inner diameter being equal.
In this way, the heat exchanging surface of the coil (through which water flows) and consequently the heating power of the boiler increase.
However, in such known operating mode boilers with coils of different diameters have different geometrical characteristics or different outer diameters as a function of the heating power generated by them. For this reasons boiler manufacturers have to realize bodies and end closing elements with different dimensions (diameters), which results in high industrial production costs and non negligible storage costs.
What described above is a "standard" for that which concerns boiler production.
WO2015/140713 describes a method to manufacture a set of heat exchange cells having a thermal power falling within a predetermined range of minimum and maximum values, each heat exchange cell comprising at least one heat exchanger mounted in a respective containment casing. The method comprises the steps of: a) providing a single containment casing of a plurality of heat exchange cells of the set, the casing having a constant axial extension as the thermal power of the cell varies within the range of thermal power values and equal to the axial extension of the cell having the minimum thermal power within the range of thermal power values; b) providing a plurality of helically-shaped heat exchangers each having a thermal
power falling within said range of minimum and maximum values and each comprising at least one tubular duct for the flow of a first heat transfer fluid coiled about a longitudinal axis of the helix according to a plurality of coils; c) mounting within said single containment casing at least one helically-shaped heat exchanger of the plurality of heat exchangers of the set. The plurality of heat exchangers of the set has an internal diameter that is substantially constant as the thermal power of the heat exchanger varies within the range of thermal power values; the tubular duct of the heat exchanger has a radial extension of the coils proportional to the thermal power of the heat exchanger and such to maintain substantially constant the axial extension of the heat exchanger as its thermal power varies and equal to the axial extension of the heat exchanger having the minimum thermal power within the range of thermal power values of the set.
WO2012/156954 relates to a heat exchanger having a heat-exchanger unit comprising one or more substantially coaxial coiled tubes and a casing for housing the heat-exchanger unit. The casing has a first end wall, a second end wall, and a peripheral part between the two end walls. Each tube has a first end and a second end. The heat-exchanger unit is supported by the first end wall of the casing, with the first end and the second end of each tube that is located substantially at the first end wall of the casing.
An object of the present invention is to offer a boiler that is capable of generating different heating powers, while having overall production costs reduced with respect to the known solutions.
Another object of the invention is to offer a boiler of the mentioned type that allows manufacturers to standardize their productions as much as possible.
Another object of the invention is to offer a boiler of the mentioned type that is easy to assemble and wherein this operation is obtainable in a short time, whatever the heating power generated by them is.
These objects and others that will be apparent to those skilled in this sector are achieved by a boiler according to the attached claims.
For a better understanding of the invention the following drawings are attached for merely explanatory, hence non limitative purposes, wherein:

figure 1 shows a partially cross-sectional schematic view of a first embodiment of a part of a boiler according to the invention;
figure 2 shows a partial top view of the part shown in figure 1;
figure 3 shows a view similar to that of figure 1, but of a different embodiment of the part of the boiler shown therein;
figure 4 shows a partial top view of the part shown in figure 3;
figure 5 shows a perspective view of a boiler according to the invention, in which some parts are omitted for the sake of clarity; and
figure 6 shows a schematic cross-sectional view of a boiler according to the invention, but comprising a horizontal heat exchanger instead of a vertical heat exchanger as illustrated in the previous figures and in which some parts are omitted for the sake of clarity.

With reference to the mentioned figures, they show a single frame 1 of a gas boiler associated with two coils or tube nests 2 and 3, having a circular cross-sectional shape (each defining a heat exchanger), comprising an identical outer diameter D, for instance equal to approximately 280 mm, and different inner diameters d₁ and d₂; for instance, the tube nest 2 in figures 1 and 2 has a diameter d₁ equal to approximately 170 mm, whereas the tube nest or coil 3 in figures 3 and 4 has a diameter d₂ equal to approximately 190 mm. It consequently follows that the cross-section S₁ of the coil 2, i.e. the distance between two portions 5 and 6 of the wall 7 of every turn 8 as measured on a plane P orthogonal to a longitudinal axis W of the coil, is greater than the corresponding section S₂ of the coil 3; consequently, the heat exchanging surface of the coil 2 is greater than that of the coil 3 and the inner cross-section of the coil 2 is greater than that of the latter. Consequently, a bigger quantity of water flows through the tube nest 2 as compared to that which flows through the tube nest 3 which, consequently, the boiler being in operation, enables the latter to generate a heating power smaller than that of the boiler to which the tube nest coil 2 belongs.
More specifically, the frame 1 comprises an annular body 10 having a predetermined diameter K and comprising a flat portion 11 from the edges of which an inner substantially vertical shoulder 12 (as referred to the longitudinal axis W of every heat exchanger that is coaxial to the frame) and a substantially vertical shoulder 13, i.e. a shoulder located on a side of the coil 8, depart. The shoulder 12 is spaced away from an upper face 15 of the flat portion 11 (with reference to the figures) and delimits a bore 17 of the annular body 10, whereas the outer shoulder 13 bends parallel to the heat exchanger 2 or 3 and is externally at least close to the latter in its most distant part from the axis W. Such shoulder 13 is close to the outer portion 6 of the wall 7 of the turn 8A located at a first end of the tube nest 2 or 3, which turn is in contact with a lower face 20 of the flat portion 11 of the frame 1.
Inside the bore 17 a usual gas burner is inserted as schematically shown in figures 1, 3, and 6 and identified by the numeral 21.
The frame 1 also comprises cylindrical bodies 23 and outer perforated tabs 24, suitable for making it possible to constrain it, by way of tie rods 57, to another portion or end element or end plate 59 of the boiler; such frame also comprises, at the free end of the outer shoulder 13, a part 25 suitable for coupling with a cylindrical tubular body 26 (or ferrule or external shell) of the boiler.
Therefore, thanks to the invention a single frame 1 having a predetermined diameter K which, in turn, defines predetermined dimensions of the cylindrical tubular body and of the outer terminal elements of the boiler, makes it possible to obtain boilers with different heating powers. As a matter of fact, as a function of the market needs or requirements, a manufacturer can couple the frame 1 with at least two different coils 2 and 3 of different inner diameters or different flow rates of a heated fluid (usually water) and subsequently associate with such frame the cylindrical tubular body 26 (indicated in dotted lines in figures 1 and 3) and shown in figures 5 and 6 and other usual components (including, water supply connectors 62 and exhaust connectors 63 for a heating system of a room in which the boiler is located and for the sanitary fittings of such room) even associated with the end element 59 to complete the boiler. In correspondence with the latter, on the body 26 there is present according to the invention an adjustable end plate 68, close to the second end 31 of the coil 2 or 3 distant from the turn 8A close to the frame. Note that the position of such end plate can be adjusted in the cylindrical body in order to bring it closer or move it away from such end 31 so as to make it possible to create, or not, a high efficiency, low emissions boiler, by preventing the steam present in the combustion smokes from being exhausted.
Furthermore, every coil is held in a coupling position with the frame 1 thanks to its constraint to the usual supply and exhaust connectors 62 and 63 respectively of the fluid that flows through the coil itself.
In an alternative embodiment of the invention, the coils 2 and 3 might have equal inner diameters, but different outer diameters. Also this solution makes it possible to achieve the objects of the invention as described above and as claimed in the following claims.

Claims

A boiler for heating rooms and producing sanitary water, said boiler comprising a tubular cylindrical body or ferrule (26), a first and a second end closing elements (1, 59) coupled with opposed ends of such body or ferrule and a heat exchanger (2, 3) having a first and a second end (31) and through which a fluid flows, said heat exchanger being placed inside the assembly formed of said body or ferrule (26) and said end closing elements (1, 59) inside said heat exchanger (2, 3) a gas burner (21) being present and being suitable for heating said fluid flowing through the heat exchanger (2, 3), the first end closing element (1) comprising a frame on which a turn (8a) located at the first end of said heat exchanger rests, the frame (1) of said first end closing element (1) having a predetermined outer diameter (K) so as to define an end element with constant dimensions associated with said body or ferrule (26) also having a fixed outer diameter, said frame being arranged to be able to co-operate alternatively with at least two heat exchangers (2, 3) having different heat exchanging surfaces, characterized in that the boiler further comprises an adjustable end plate (68) located in proximity to the second end (31) of said heat exchanger (2, 3) distant from the frame of the first end closing element (1),the position of said adjustable end plate (68) being able to be adjusted in order to bring it closer or move it away from said second end (31) so to prevent the steam present in the combustion smokes from being exhausted and so to be able to create a high efficiency, low emission boiler.
A boiler according to claim 1, characterized in that every heat exchanger comprises a coil or tube nest (2, 3) having the turn (8a) located at the first end of the heat exchanger constrained to said frame, connectors (62, 63) being provided to supply and exhaust the fluid in/from said coil (2, 3), the connection of the latter to said connectors associating the heat exchanger (2, 3) with said frame of the first end closing element (1) in a stable manner.
A boiler according to claim 2, characterized in that said connectors (62, 63) are placed in correspondence with said frame of the first end closing element (1) and with the second closing element (59) located at the opposite end of the tubular body or ferrule (26) with respect to said frame.
A boiler according to claim 2, characterized in that the coils (2, 3) that can be associated with said frame have an identical outer diameter (D), but different inner diameters (d₁, d₂).
A boiler according to claim 2, characterized in that the coils (2, 3) that can be associated with said frame have an identical inner diameter, but different outer diameters.
A boiler according to claim 1, characterized in that said frame of the first end closing element (1) has an annular body (10) having a flat portion (11) delimiting an inner bore (17) wherein said gas burner (21) is inserted, said flat portion (11) having an inner edge from which an inner shoulder (12) rises and having an outer edge from which an outer shoulder (13) rises, said shoulders (12, 13) are directed to opposite directions, the outer shoulder (13) being at least close to an outer portion (6) of a wall (7) of the turn (8A) located at a first end of the heat exchanger (2, 3), said turn being in contact with a face (20) of said frame.
A boiler according to claim 6, characterized in that said outer shoulder (13) comprises a part (25) suitable for co-operating with the tubular body of the boiler, said part (25) being preferably preset to such co-operation.