Patents
Search within the title, abstract, claims, or full patent document: You can restrict your search to a specific field using field names.
Use TI= to search in the title, AB= for the abstract, CL= for the claims, or TAC= for all three. For example, TI=(safety belt).
Search by Cooperative Patent Classifications (CPCs): These are commonly used to represent ideas in place of keywords, and can also be entered in a search term box. If you're searching forseat belts, you could also search for B60R22/00 to retrieve documents that mention safety belts or body harnesses. CPC=B60R22 will match documents with exactly this CPC, CPC=B60R22/low matches documents with this CPC or a child classification of this CPC.
Learn MoreKeywords and boolean syntax (USPTO or EPO format): seat belt searches these two words, or their plurals and close synonyms. "seat belt" searches this exact phrase, in order. -seat -belt searches for documents not containing either word.
For searches using boolean logic, the default operator is AND with left associativity. Note: this means safety OR seat belt is searched as (safety OR seat) AND belt. Each word automatically includes plurals and close synonyms. Adjacent words that are implicitly ANDed together, such as (safety belt), are treated as a phrase when generating synonyms.
Learn MoreChemistry searches match terms (trade names, IUPAC names, etc. extracted from the entire document, and processed from .MOL files.)
Substructure (use SSS=) and similarity (use ~) searches are limited to one per search at the top-level AND condition. Exact searches can be used multiple times throughout the search query.
Searching by SMILES or InChi key requires no special syntax. To search by SMARTS, use SMARTS=.
To search for multiple molecules, select "Batch" in the "Type" menu. Enter multiple molecules separated by whitespace or by comma.
Learn MoreSearch specific patents by importing a CSV or list of patent publication or application numbers.
Heat exchanger for use in a central heating boiler or the like and heating apparatus comprising such a heat exchanger
EP0021512A1
European Patent Office
- Other languages
German French - Inventor
Jan Aede Stapenséa - Current Assignee
- Rheem Nederland BV
Description
translated from
-
[0001] The invention relates to a heat exchanger for use in a central heating boiler or heating apparatus, said exchanger comprising a plurality of sections arranged side by side add having each a fluid chamber intercommunicating through an inlet and outlet nipple, a flue passage channel being formed between the sections,in which channel project pins arranged on the sidewalls of the sections. -
[0002] In the heat exchanger of the kind set forth in the preamble the fluid contained in the sections is heated by heat transfer from the flue gases across the walls of the sections to the fluid. -
[0003] The pins projecting in the flue channels serve to improve this heat transfer. In practice it has, however, been found that despite the many shapes of the pins employed the efficiency of such a heat exchanger is comparatively low. -
[0004] The invention has for its object to provide a heat exchanger which produces such a turbulence of the flue gases that the heat transfer from the flue gas to the wall of the heat exchanger becomes optimal, whilst the flow of the fluid in the sections is improved so that the heat absorbed from the walls of the sections is transferred to the optimum to the fluid. -
[0005] According to a first aspect of the invention the outer surface of the pins is flattened along the circumference at one or more places, the flat surface of the pin being at an.angle to the direction of length of the flue channel. Thus the flow of the flue gases in the flue channel formed between the sections is subjected to a change of direction, as a result of which the flue gas particles are mixed. -
[0006] In a preferred embodiment the pins are arranged in rows inclined to the direction of length of the flue channel, the flat surfaces of the pins being parallel to the row so that inclined flow channels are formed in the flue channel. -
[0007] In order to obtain a relatively longer residence time of the hot flue gas on the affluent side of the heat exchanger, the rows of pins are disposed so as to converge in the direction of passage of the flue channel. Thus progressively narrowing flow channels are formed, which have a kind of venturi effect on the flue gas. -
[0008] As an additional measure in this respect the distance between the pins of the same row can be progressively reduced in the direction of passage of the flue channel. -
[0009] In order to enhance the turbulence in the flue channel the flat surfaces on the pins on one side of a section are specularly symmetrical to the other side. In assembling the sections crossing flow channels will form in the flue channel and produce violent turbulence of the flue gas at the interface between the sections. -
[0010] In order to obtain a satisfactory heat transfer between the wall of a section of the heat exchanger and the fluid contained therein, the fluid chamber comprises one or more guide partitions. -
[0011] From the inlet nipple these partitions are preferably converging towards the section wall bombarded by the flue gas as a result of which the rate of flow of the fluid in the section along this hot wall will be high and hence also the cooling effect. -
[0012] The invention will be described more fully with reference to a drawing. -
[0013] The drawing shows in: - fig.1 a perspective view of a heating apparatus comprising a heat exchanger in accordance with the invention,
- fig.2 a side elevation of a section used in the heat exchanger,
- fig.3 and 4 a bottom view and a.plan view respectively of the section of fig.2,
- fig.5 a sectional view taken along the bottom side of the section of fig.2,
- fig.6 and 7 a plan view and a side view respectively of a pin mounted on the sidewall of the section.
-
[0014] -
[0015] The heat exchanger 2 consists of a series ofsections 7 arranged side by side to be described more fully hereinafter with reference to figs. 2 to 6. Between the sectionsflue gas channels 8 are formed so that the flue gases emanating from the burner 1 can flow through thesechannels 8 towards theoutlet pipe 6. -
[0016] The section shown in fig.2 is mainly formed by a hollow casing in which a fluid chamber is formed, which communicates through aninlet nipple 9 and anoutlet nipple 14 with the chambers of the neighbouring sections. The sidewall of thesection 7 has a substantially rectangular shape and has a large number ofpins 10 projecting into theflue channel 8 formed between two sections. The pins shown in fig.2 are disposed in converging rows, which is indicated by the line I-II in fig.2. On both sides of its circumference eachpin 10 has a flat surface 11 (see also fig.6). The flat surfaces extend parallel to the row of pins so that between the rows of pins flow channels are formed which are in a position inclined to the main direction of flow of the flue gas from bottom to top. -
[0017] In the direction of flow of the flue gas the distances between the pins of a row decrease. -
[0018] On the bottom side or the affluent side of thesection 7 are arranged guide ribs 15: see also fig.3. -
[0019] According to one aspect of the invention thesurfaces 11 of thepins 10 are mirror-symmetrical on both sides of asection 7 as shown in fig.4. It will be obvious that in assembling the sections the rows 1 - 2 on one side (fig.2) will cross those on the other side fo the same section so that in assembling twosections 7 thepins 10 facing one another will be in crosswise positions. -
[0020] Intthe fluid chamber of thesection 7, near itsaffluent side 12 are arrangedinternal guide partitions 13 converging from theinlet stub 9 towards theaffluent side 12. In the embodiment shown five partitions are arranged in overlapping positions in a manner such that the fluid from theinlet stub 9 will mainly flow along thewall 12 and will partly find its way between the partitions 13 (see the arrows Pl and P2). Owing to thesepartitions 13 the rate of flow P1 will be relatively high whilst no dead corners will be formed in the fluid chamber of thesection 7, so that optimum heat transfer is ensured. -
[0021] The invention is not limited to the embodiment described above. For example, the pins may as an alternative be disposed in staggering rows I,II so that the flow direction of the flue gas in the flow channel changes repeatedly. This may further enhance the desired turbulence.