FR2497926A1 - Sectional boiler working at reduced pressure - has integral insulation to provide hot water or low pressure vapour - Google Patents

Abstract

The boiler can use either combustible liquids or gas and has a front (4) and back (8) facade forming water tanks with groups of lateral heat exchangers (12) between them. The exchangers are thin water filled panels separated from each other by circulation ducts (17) which carry the combustion gases. Two water supply tanks (1) are provided at the base and form the hearth bottom (16) while a water tank (3) in the roof forms the water exit. The burner enters through a door (15), and flame control is aided with an inspection hole (7). Mobile stoppers (13,14) aid cleaning and chimney sweeping.

Description

 The invention relates to a high efficiency sectional boiler for the production of hot water or low pressure steam.

 We already know (French patents NO 1 061 207 and NO 1 131 617) boilers sectioned longitudinally and transversely in which, between the front and rear double wall facades, are arranged lamellar exchangers oriented transversely, these front and rear facades lamellar exchangers being assembled by a longitudinal central upper collector and by two longitudinal lateral lower collectors, this assembly resting on a masonry base coated with a refractory brickwork constituting the lower wall of the boiler hearth.

 This known type of boilers, the sectioning of which allows disassembly and reassembly from elements of small dimensions, has the advantage of being able to be easily introduced into any boiler room having an entry required.

However, these known types of boilers still have a certain number of drawbacks, resulting in heat losses mainly coming from
- of the masonry base receiving the refractory brickwork and closing the hearth at its lower part,
- thermal insulation covering comprising numerous thermal bridges with the internal part of the boiler,
- insufficient exhaustion of gases to allow efficient yields to be obtained.

 The object of the present invention is to remedy these drawbacks and to reduce the heat losses to a level largely compatible with the new requirements concerning energy savings.

 To this end, the invention relates to a sectioned vacuum boiler, for the high-efficiency production of hot water or low pressure steam, this boiler comprising a hearth chamber completely surrounded by exchange surfaces with lower boots forming sole with water circulation, with a thermal insulation covering independent of the heating body to avoid any thermal bridge, and with a combustion gas circuit ensuring a path as long as possible of these combustion gases in contact with walls of which the other side is irrigated by the circulation water of the boiler so as to lower the temperature of the combustion gases to the minimum level compatible with the longevity of the equipment, the water paths in contact with the combustion gases comprising sections of significant circulation of water, arranged in such a way that the heat exchange walls are largely irrigated to avoid any possibility of overheating and scaling.

 The groups of sectioned elements are mounted between a front facade and a rear facade as well as between two lateral water blades, supplied from the return collectors, which means that the heating body of the boiler is entirely surrounded by parts traversed by water at a relatively low temperature limiting thermal losses to the outside, which allows optimal use of the calorific value of the fuel and a very significant improvement in the efficiency of the boiler.

The invention will be explained in more detail with reference to an example shown without limitation in the accompanying drawings in which
FIG. 1 represents the boiler according to the invention seen from its front face, on the one hand, in elevation, on the other hand, in half-section,
FIG. 2 represents the same boiler seen from its rear face,
FIG. 3 is a longitudinal section of the boiler according to the invention,
- Figure 4 is a top view of the boiler according to the invention, in elevation and in half-section along the line aa of Figure 1
- Figure 5 shows in perspective a removable assembly consisting of a lower boot and an upper boot connected together by transverse elements.

 The boiler according to the invention comprises groups of elements each consisting of a lower box 1 forming a floor, a battery of planar elements 2 oriented vertically and an upper boot 3 forming a hearth. A front panel 4 constituting a water boot comprises an opening 5 for the passage of the burner, orifices 6 for removing the soot as well as a flame control window 7. A rear panel 8, also forming a water boot, has two smoke outlet orifices 9 and a smoke collecting boot 10 with a general smoke evacuation 11. The boiler also has two lateral water blades 12. I1 mobile lower buffers 13 are provided delimiting the gas circuit and allowing to access the elements for sweeping as well as movable upper buffers 14 closing the groups of elements and giving access for cleaning.

 The burner, mounted in the opening 5 on an articulated door 15, develops its flame in the enclosure 16 of the hearth, the conformation of this enclosure being studied so that the flame develops at the level of the lower boots. The combustion gases are evacuated to the upper part of the chamber by the passages 17 delimited by the elements 2 and the plates 18 welded between these elements. The upper part of the elements being closed by the lower buffers 13, the combustion gases descend by the conduits 17A delimited on the one hand by the faces of the elements 2, on the other hand, on the side of the hearth by the dishes 18 and towards the outside by the dishes 19, to arrive in the lower expansion chamber 2QA. The combustion gases then rise through the conduits 17B delimited on the one hand by the faces of the elements 2, the dishes 19 and the lateral water blades 12 to reach the upper expansion chamber 20B before being evacuated by the orifices 9 of the rear facade 8 in the smoke collecting boot 10 and to be evacuated outside the boiler by the outlet 11. Balancing flaps 21 allow the chimney draft to be adjusted as desired.

 The water supply to the boiler takes place via a general return 22 of the heating installation which serves two lower collectors 23, while the hot water or low pressure steam is evacuated from the boiler through a general collector 24.

 The water to be heated from the lower collectors 23 passes through the groups of elements 2 via the inlet pipes 25 located at the low point of the lower water boots 1. Deflectors 26, placed in these boxes water forming the sole, ensure a good distribution of the water which then passes through the elements 2, then into the upper boots 3 in order to be discharged at the upper part of these boxes through the pipes 27 in the general starting manifold 24.

 The front face 4 and the rear face 8 are supplied from the collectors 23 by the pipes 28 and their evacuation takes place in the general starting manifold 24 by the pipes 29.

 The lateral blades 12 are supplied from the collectors 23 via the pipes 30 and their evacuation takes place on the front panel by the pipes 31.

 All these constituent elements are connected to the return 33 and departure 24 collectors by pipes 25, 27, 28, 29 and 30 and thus constitute an enclosure completely surrounding the hearth with the exception of the opening 5 of the burner and the outlets combustion gases.

 This assembly is protected against heat loss to the outside by an independent thermal insulation covering consisting of a frame of profiles 32 receiving insulating panels 33 coated with a refractory material.

 The boiler thus constituted allows optimal use of the calories extracted from the fuel, which can preferably be a liquid or gaseous fuel, it thus meets the new requirements formulated in terms of energy saving. I1 is obvious that the invention is not limited to the embodiment described and shown above from which we can provide other variants without departing from the scope of the invention.

Claims (4)

 10) Vacuum boiler for the high output production of hot water or low pressure steam, preferably using liquid or gaseous fuels, sectional boiler comprising, between a front panel and a rear panel constituting water tanks, groups lateral exchanger elements forming transverse water layers separated from each other by intervals of circulation of the combustion gases, these front and rear facades as well as these transverse elements being assembled by two lower supply manifolds and an upper flow manifold , the assembly being surrounded by a thermal insulation covering, a boiler characterized in that it comprises lower boots of water (1), the assembly of which forms the hearth hearth (16), each of these lower boots (1) being associated with a battery of transverse, planar and vertical water circulation elements (2), and with an upper water box (3), the assembly of these upper boxes (3) constituting the sky of the hearth (16), the boiler also comprising a front facade (4) forming a water box and comprising the passage (5) of the burner, soot removal orifices (6), as well as '' a flame inspection port (7), and a rear facade (8) comprising two smoke outlet orifices (9) and a smoke collecting boot (10) connected to a general smoke evacuation (11), the boiler also comprising two lateral water blades (12), lower (13) and upper (14) movable buffers delimiting the circuit of combustion gases and allowing access for cleaning and sweeping.  20) Boiler according to claim 1, characterized in that the combustion gases generated by the burner, carried by a plate (15) in the orifice (5) of the front panel (4) of the boiler, are evacuated to the upper part of the hearth by orifices (17) delimited, on the one hand, by the transverse elements (2) and 1 upper water box (3) and, on the other hand, by dishes (18) connecting the elements transverse (2), then are channeled downwards into delimited channels, (17A) on the one hand, by the transverse elements (2) and, on the other hand, by the dishes (18) on the hearth side and by dishes (19) on the outside, to reach a lower expansion chamber (20A) and go up by passages (17B) delimited by the dishes (19) and the lateral water bundles (12) towards an upper smoke chamber ( 20B) to reach the general smoke collecting box (10) connected to the general exhaust (11).  30) Boiler according to any one of claims 1 and 2, characterized in that the boiler is supplied with water by the general return manifold (22) of the heating installation, connected to the lower supply manifolds (23) from the boiler, this water passing through the lower water bundles (1) forming the hearth hearth (16) via pipes (25), then passing through the transverse elements (2) in the upper water boxes (3) and be evacuated via pipes (27) in the general starting manifold (24), the supply manifolds (23) being on the other hand connected via pipes (28) to the water boots t4, 8) of the front and rear facades of the boiler themselves connected via pipes (29) to the general starting manifold (24) of the boiler, the water tanks side (12) themselves being connected to the supply manifolds (23) by means of pipes (30) and with the front face (4) of the boiler by means of pipes (31).  40) Boiler according to any one of claims 1 to 3, characterized in that the heating assembly, consisting of the hearth (16), the lower water boots (1), the transverse elements (2), the boots water tanks (3), the front (4) and rear (8) facades, and the lateral water boots (12), as well as the supply (23) and outlet (24) collectors, is surrounded by a thermal insulation covering made up of profiles (32) on which panels of thermally insulating materials (33) are mounted, this external thermal insulation covering resting on the ground and having practically no contact with the aforementioned assembly.