GB2056651A

GB2056651A - Sectional radiators for air cooling oil-filled transformer housings

Info

Publication number: GB2056651A
Application number: GB8014211A
Authority: GB
Original assignee: MENK APPARATEBAU GmbH
Current assignee: MENK APPARATEBAU GmbH
Priority date: 1979-07-05
Filing date: 1980-04-30
Publication date: 1981-03-18
Also published as: ATA99880A; DE2927151A1; IT8048701A0; AT380582B; YU39871B; FR2460534A1; IT1207113B; YU7580A; SE8000580L

Abstract

A radiator for use in cooling the oil in an oil-filled transformer vessel or housing, comprises two edge-welded half-shells, each half-shell having a plurality of first indented portions (6,7), corresponding first indented portions on the two half-shells being welded together to define longitudinal channels (8), an upper boss or hub (2) being provided on each half-shell, the first indented portions each being interrupted once in the region of the upper boss or hub to define channels in such a manner that oil throughflow channels (12) extending diagonally downwards from the upper boss or hub in both directions are formed which channels (12) connect one longitudinal passage (8) to another, wherein further indented portions (13) having a lesser depth of indentation than the first indented portions (6,7) are provided between the first indented portions, so as to form flow channels of reduced thickness in the longitudinal channels (8). <IMAGE>

Description

SPECIFICATION Radiator for use in cooling the oil of oil-filled transformer vessels or housings The present invention relates to a radiator for cooling the oil of oil-filled transformer reservoirs.

A known radiator of this type comprises individual radiator members formed of half-shell members having upper and lower bosses. For the purpose of mechanical stability, the two sides of the radiator members are provided with mutually facing indentations which are welded together. In this manner longitudinal channels in the radiator member are defined. The indentations and therewith the end regions of the longitudinal channels in the region of the upper boss are each interrupted in such a manner that a diagonally downwardly and outwardly extending oil flow passage is formed from one longitudinal channel to the channel adjacent thereto.

Such radiators exhibit excellent oil-cooling properties but it is desirable, from an economic point of view, to minimise the material used in the manufacture of such radiators.

The present invention therefore seeks to provide a radiator of this general type in which there is no reduction in the cooling efficiency but in which the oil-filling capacity and the amount of material, generally steel plate, can be reduced without impairing the stability of the radiator.

According the present invention, there is provided a radiator for use in cooling the oil in an oil-filled transformer vessel or housing comprising two edgewelded half-shells, each half-shell having a plurality of first indented portions, corresponding first indented portions on the two half-shells being welded together to define longitudinal channels, an upper boss or hub being provided on each half-shell, the first indented portions each being interrupted once in the region of the upper boss or hub to define channels in such a manner that oil through flow channels extending diagonally downwards from the upper boss or hub in both directions is formed which channels connect one longitudinal passage to another, wherein further indented portions having a lesser depth of indentation than the first indented portions are provided between the first indented portions so as to form flow channels of reduced thickness in the longitudinal channels.

It has been found that the provision of the further indented portions does not necessitate further welding in this region and hence brings about a reduction in the channel division without loss of radiator stability. The use of substantially thinner metal plates is therefore made possible. At the same time, without reducing the cooling efficiency, the quantity of oil used is considerably reduced. Thus, plates having a minimum thickness of 1.2 mm have hitherto been used but now 1 mm plates can be used. This represents a reduction in the volume of oil required to fill the radiator of more than 15%. This reduction in the oil volume does not cause any loss of cooling efficiency.It has, in fact, been found that, due to the increase in the flow velocity of the oil in the reduced cross-sectional area channel in combination with the improvement of the airflow conditions between the radiator ribs an improvement in the cooling efficiency is attained. This is particularly noticeable in radiators which operate with an air circulation assisted by a fan. With lateral inblowing of air, more turbulent airflow occurs in the region of the further indented portions by means of which the heat transfer is substantially improved.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure lisa view of the head region of a radiator component in accordance with the present invention, Figure 2 is a section through a half-shell of the radiator member shown in Figure 1, Figure 3 is a view of an alternative embodiment of a radiator component in accordance with the present invention, and Figure 4 is a section through a half-shell of the radiator member of Figure 3.

In Figures 1 and 3 of the drawings, there is shown a radiator component which is provided with an upper boss 2 and similarly, although not shown, with a lower boss. The radiator component, as can be seen from Figures 2 and 4, is formed from half-shell members 3, whereby each pair of half-shell members are mirror images of one another and are welded together at their edge flanges 4 and in the indented regions 5,6,7 in such a manner that wall portions 8 located between the indented regions form longitudinal channels 9 for carrying coolant such as oil. The lateral indented portions 6 and 7 shown in Figure 1 define the longitudinal channels 9 and also therefore the traversing stops of the longitudinal channels in the region of the upper boss.These indented portions are interrupted at one point so as to form channels 10 or 11 in such a manner that a transfer channel 12 for the oil is formed which extends diagonally downwardly from one vertical longitudinal channel to the next. This makes possible an internal oil transfer within the radiator to compensate for disproportionate reductions in the temperature gradient set up in the outer region due to increased efficiency and to arrive at a specific load per surface area taking the varying cooling conditions into account. The overall performance is, as measurements have proved, substantially improved by this feature.

Moreover, between the welded lateral indented portions 6, 7, that is to say, in the region of the longitudinal channels 9, further indented portions 13, best seen in Figure 2, are provided. The portions 13 are less deep than the portions 6 and 7 and define flow channels 14 of a reduced depth. The plate thickness of the half-shells is, in a radiator having a channel division of 85 mm, 1 mm, the longitudinal channels 9 have a depth of 9 mm and the flow channels 14 have a depth of only 5 mm whilst corresponding reductions in the cross-sections for the oil to flow through are provided.

The radiator is, as shown in Figure 1, provided with indented portions 13 extending over its entire length, but these portions may, similarly to the portions 6 and 7, also be interrupted.

In the embodiment shown in Figures 3 and 4, in which corresponding parts to those shown in Figures 1 and 2 are denoted by the same reference numeraLs, a plurality of indented portions 15 are provided in the channel plate between the indented portions 5, 6, 7. These portions 15 have a lesser depth and a reduced width than the portions, 5, 6 and 7. Such an arrangement improves the radiator with increased stability compared with the embodimenu shown in Figure 1,and further increases the heat conducting surface area. Due to the repeated alternate constriction and enlargement of the airpath cross-section in the region of the oil passage, especially if a lateral air stream is blown in by means of fans, a more intensive turbulence of the air flow and corresponding improvement in the heat transfer characteristics is obtained.

Claims

1. A radiator for use in cooling the oil in an oil-filled transformer vessel or housing comprising two edge-welded half-shells, each half-shell having a plurality of first indented portions, corresponding first indented portions on the two half-shells being welded together to define longitudinal channels, an upper boss or hub being provided on each half-shell, the first indented portions each being interrupted once in the region of the upper boss or hub to define channels in such a manner that oil throughflow channels extending diagonally downwards from the upper boss or hub in both directions is formed which channels connect one longitudinal passage to another, wherein further indented portions having a lesser depth of indentation than the first indented portions, are provided between the first indented portions so as to form flow channels of reduced thickness in the longitudinal channels.

2. A radiator as claimed in claim 1, wherein a plurality of further indented portions are provided between each adjacent pair of first indented portions.

3. A radiator as claimed in claim 1 or 2, wherein the further indented portions extend continuously over the entire length of the radiator.

4. A radiator as claimed in claim 1 or 2, wherein the further indented portions are interrupted at least once along the length of the radiator.

5. A radiator for use in cooling an oil-filled transformer vessel or housing constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in Figures 1 and 2 or Figures 3 and 4 of the accompany ing drawings.