The invention relates to a pipe comprising a device for optimizing the transmission of heat therein according to the preamble of claim 1. Such combinations pipe-devices are known from US 3,394,736.

Heat exchange apparatuses are known, such as for example fire tube boilers for producing hot water or other heat transfer fluids, which provide for the presence of pipes intended to convey exhaust gases produced by combustion in adapted furnaces, which are inserted within a vessel that contains the fluid to be heated.

However, pipes of this type are not typical exclusively of boilers, but can also be present in different apparatuses of industrial cycles.

From the point of view of heat transmission, conventional pipes are not entirely satisfactory, even if they are provided with internally inserted elements intended to make the transmission particularly efficient.

The aim of the present invention is to provide a device that can optimize effectively the characteristics of heat transmission between the exhaust gases conveyed by the pipes and the fluid that flows on the outside of the pipes.

This aim, as well as other objects that will become better apparent hereinafter, are achieved by a pipe according to claim 1.

Further characteristics and advantages of the invention will become better apparent from the description of preferred but not exclusive embodiments of the invention, illustrated by way of non limiting example in the accompanying drawings, wherein:

• Figure 1 is a perspective view of a device not corresponding to the invention;
• Figure 2 is a sectional view, taken along line II-II of Figure 1;
• Figures 3 to 6 represent embodiments not corresponding to the invention;
• Figures 7, 9 are perspective views of variations of the device according to the invention;
• Figures 8, 10 are sectional views, taken respectively along lines VIII-VIII, X-X of Figures 7, 9 respectively.

With reference to Figures 1 and 2, the numeral 1 generally designates the device according to the invention, inserted in a pipe 2 designed to convey inside it a stream of exhaust gases and to be lapped externally by the fluid to be heated.

The device 1 comprises, in a single piece assembly, a plurality of longitudinal fins 3, which extend in a substantially radial direction from a central core 4 and come into contact with the inner surface of the pipe 2.

More precisely, the individual fins 3 have a slight curvature, which enhances their elasticity characteristics both during the insertion of the device in the pipe and during operation. Such fins further have an end 3a which is widened so as to define a foot for contact with the inner surface of the pipe.

The presence of the device according to the invention gives great effectiveness to the transmission of heat between the exhaust gases conveyed by the pipe 2 and the fluid that laps the pipe externally, because the fins 3 convey, by conduction, to the pipe wall the heat captured at the central portion of the pipe, where the exhaust gases are hotter, and moreover the inner surface of the pipe wall is lapped directly by the stream of exhaust gases without any obstacle being interposed so as to constitute a shield to the flow of heat.

Figures 3 and 4 are views of a first variation of the invention, which no longer has a single piece configuration but comprises two sections, generally designated by the reference numerals 5 and 6, each comprising a portion of the central core which is provided with respective fins. Thus, the section 5 comprises a portion 5a of the central core with respective fins 5b, 5c, 5d, 5e, and the section 6 comprises a portion 6a of the central core with respective fins 6b, 6c, 6d, 6e.

The variation shown in Figures 5 and 6 again comprises two sections 7 and 8, each of which comprises a portion of the central core which is provided with respective fins, and provides for the presence of an expander, which is extended over the entire length of the device and is adapted to keep the sections in contact with the inner surface of the pipe and is constituted by a threaded stem 9, which is shown partially extracted for clarity of illustration.

Finally, the variations shown in Figures 7, 8 and 9, 10 are structurally identical to the variation of Figure 5 and are provided with a turbulator, which is adapted to disrupt the boundary layer of the stream of exhaust gases in contact with the inner surface of the pipe and is inserted in an adapted seat provided at the outer end of the fins.

These variations correspond to the claimed invention. The turbulator comprises, in the variation of Figure 7, a plurality of rings 10, whereas in the variation of Figure 9 it has the shape of a spiral 11.

In practice it has been found that the device according to the invention fully achieves the intended aim.

The invention thus conceived is susceptible of numerous other modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.