JPS5924794B2 - Methods of heating heat exchangers and heat exchange fluids - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchanger for heating or cooling a fluid, in particular a fluid that is conveyed at a constant temperature into a service circuit.

Conventional fluid heating is based on direct contact with the heating surface of the heating device used (it is known that the fluid gradually decomposes due to localized heating).

However, for some reason in the industrial use of heated fluids, and in order to increase their heating rate to a maximum, it is necessary to have heated surfaces to temperatures much higher than can be tolerated without risk of decomposition of these fluids. It is generally accepted that

This therefore involves the construction of large boilers presenting a large heating surface, which is often disadvantageous from the point of view of the space required or from the point of view of the economic investment involved.

The object of the invention is to eliminate the above-mentioned drawbacks and therefore to provide a heat exchanger for heating or cooling fluids, the size of which for the same power and efficiency is much smaller than the known devices. .

The object of the invention, which seeks to achieve the above objects, therefore consists of: a chamber with an external heating or cooling device; and an apparatus for heating or cooling a fluid, characterized in that it includes a device for conveying the heated or cooled fluid to an external use circuit.

The object intended by the invention is therefore a pump intended to circulate fluid at high velocity in boiler shunts or all row chambers, and to provide local superheating or subcooling of the fluid in contact with these walls. This is obtained by a combination of "scraping" or "sweeping" devices of the heating or cooling inner walls intended to prevent heating or cooling.

A heat exchanger for heating or cooling fluids according to the invention will be described, by way of example only, with reference to the accompanying drawings, in which: FIG.

In the embodiment shown schematically and partially in section in said drawings, the heat exchanger, in particular the heating device, comprises a boiler consisting of a body 1 and a cylindrical part 2 perpendicular to said body 1, the cylindrical the shaped part is made of a good heat transfer material, and
It is heated by a conventional external device, indicated here by arrow 1, for example by an electric resistance heater.

The drum 3 is mounted concentrically inside the cylindrical part 2 of the boiler and is rotated and driven by a shaft 4 of a motor 5, said shaft 4 corresponding to the central axis of said cylindrical part 2.

The outer surface of drum 3 is helicoidal 5p.
iral ), this assembly forms an endless thread, the upper end of which slides in close proximity to the internal heating surface of the cylindrical part 2 without contact.

In other embodiments, the helix 6 is single or multiple;
For example, trapezoidal, triangular or semicircular threads can be substituted.

Furthermore, the gap between the helical thread 6 and the cylindrical part 2 is made as small as the processing limits and the materials used allow, in order to prevent seizure.

The cylindrical part 2 of the boiler is further closed by an element 7, which is used as a cover and close to the central feed pipe 8 and its outer circumference and also inside the drum 3 in the position of use shown in the accompanying drawings. , comprising two parallel cylindrical walls 9, said cylindrical walls defining a chamber 9' between them.

The free end of said chamber 9' is closed and joined to the cover 7, and the other end contains two openings, an inlet 10 and an outlet 11, respectively, for a cooling fluid, for example water.

The boiler further includes a peripheral pump 12 at the intersection of the inner wall of the cylindrical part 2 and the inner wall of the body 1, while the body 1 itself is bored with an outflow groove 13 connected to an outlet pipe 14.

A fluid intended to be heated to a constant humidity for use in its external circuit, for example heating oil, was restricted by the supply pipe 8 and by the inner wall 9 of the chamber according to the arrow .
It is introduced into chamber 15.

The oil then passes between the outer wall 9 of said chamber 9' and the inner wall of the drum 3 and is then carried away by the helix 6 of the rotating drum 3, which acts like a screw conveyor.

The helical screw 6 is primarily used to destroy the outer layer of oil which tends to pool against the inner wall of the cylindrical part and thereby prevent the heating of the remainder of the oil by its poor thermal conductivity. It will be done.

Heat exchange in the circulating oil heating reservoir can thus take place effectively and without the risk of local overheating.

When the heated oil, carried away by the screw conveyor, reaches the vicinity of the boiler body 1, it is sucked in, for example by a peripheral pump, and then into the outflow groove 113 and into the outflow pipe 1.
4 to an external utilization circuit (not shown) (arrow 3).

Furthermore, a thermometer 16 is introduced, for example in the outlet channel 13, to check the outlet temperature of the oil.

The measured temperature can still be used to control functions through the automatic regulator, external heating ■ intensity control circuit.

Furthermore, in order to improve the efficiency of the temperature regulating device, it is likewise possible to bring the regulation of the temperature and/or the output of the cooling fluid circulating in the chamber q according to the arrows 1 and V under the control of the thermometer 16.

Of course, the heat exchanger according to the invention described above (not shown)
Other embodiments may be considered as illustrative only.

For example, it is possible to use scraping segments or other scraping and/or stirring devices installed in the immediate vicinity of said surfaces as devices for circulating the liquid over the heated surfaces of the boiler: as described with reference to the accompanying drawings. The peripheral pumps provided can also be replaced by other types of pumps such as suction pumps, gear pumps, positive displacement pumps, etc.

The main advantages of the heat exchanger for heating fluids according to the invention are its size/heating rate and efficiency ratio.

In fact, for example, it has a size of 15CTLX 15cm (
For a device according to the invention (not including the drive motor), with a circulation speed of a liquid, e.g. normal heating oil, of approximately 10-15 m/sec (rotational speed of the endless screw: approximately 3000 revolutions/min) It is possible to apply heating powers greater than 10w/crrL2, whereas with conventional equipment of the same size the applied heating power is approximately 1.8w without the risk of relatively rapid decomposition of the oil. /crn2 cannot be exceeded.

Furthermore, in the heat exchanger according to the invention, even in the case of any cessation of fluid circulation in the external circuit, as long as the endless screw is driven in rotation, said fluid is continuously moved over the heating surface. This eliminates the risk of oil decomposition due to overheating.

The inventive elements of the invention, described with reference to the above specific embodiments, allow to achieve a reduction in the size of a fluid heating device by a factor of about 5.

Of course, a device similar to that described with reference to the accompanying drawing only can be used as a heat exchanger for cooling fluids.

Therefore, it is only advisable, on the one hand, to replace the external heating device (1) by an external cooling device, for example a circuit of refrigeration fluid, and, on the other hand, to achieve a more effective temperature regulation. It is only recommended to provide circulation of the heating fluid within the chamber 9' by means of the arrows ■ and V.

The heat exchanger according to the invention, when used with a fluid cooling device, on the one hand, offers a considerable reduction in magnitude with respect to known devices with the same cooling output and efficiency, as in the case of a heating device. On the other hand, continuous forced circulation against the cooling wall offers the advantage of avoiding unnatural viscosity changes or even partial crystallization of the fluid due to local supercooling.

Although this invention has been illustrated and described with reference to a preferred embodiment, it will be understood that modifications and variations may be made without departing from the spirit of this invention, as will be readily understood by those skilled in the art. Should.

It is believed that such modifications and variations are within the scope and scope of this invention as limited by the scope of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS The drawing shows an embodiment of the heat exchanger of the present invention. Symbols in the figure: 1... Main body of the heat exchanger, 2... Cylindrical part of the heat exchanger, 3... Drum, 4... Rotating shaft,
5... Motor, 6... Scraping spiral, 7... Closing element, 8... Supply pipe, 9... Cylindrical wall, 10...
・Fluid population, 11... Fluid outlet, 12... Peripheral pump, 13... Outflow groove, 14... Outflow pipe, 15...
Room, 16...Thermometer.

Claims (1)

[Scope of Claims] 1. A heat exchanger used in an external heat utilization type circuit, wherein 2. a) a heating wall for heating said fluid; and b) a heating wall for said heat exchange fluid of approximately 1.8 W/cr
c) heating means for heating the heating wall in order to provide an amount of heat equal to or greater than fL2; c) cooling means for cooling the heat exchange fluid; d)
means for measuring the exit temperature of the heat exchange fluid from the heat exchanger; and means for adjusting the cooling and heating means to maintain the fluid at a desired temperature; e) the fluid is attributable to decomposition; A stirring means for stirring the fluid circulating in the heating chamber to prevent local overheating, and a stirring means for operating the stirring means so that the fluid flows in the heating chamber at a flow velocity of 10 m/s. f) means for circulating said fluid in said circuit in addition to said stirring means. 2. The heat exchanger according to claim 1, wherein the heating wall is cylindrical and the stirring means is a spiral located close to the heating wall. 3. The heat exchanger according to claim 2, wherein the helix is a single or multiple thread. 4. The heating wall has a cylindrical shape, and the stirring means is further located close to the heating chamber so as to improve heat exchange between the heating wall and the fluid, and the stirring means is arranged to draw the fluid from the heating wall. The heat exchanger according to claim 1, which is a scraping means for sweeping. 5. The heat exchanger according to claim 1, wherein the gap between the stirring means and the heating wall is made as small as possible by processing limits, while still being formed to prevent seizure. . 6. The heat exchanger according to claim 1, wherein the heating chamber is formed by the heating wall and a second wall. 7. The heat exchanger according to claim 6, wherein the heating wall is cylindrical, and the stirring means is a rotatable screw attached to the second wall. 8. Claim 7, wherein the stirring means further comprises a drum rotatable coaxially within the cylindrical heating wall, and the heating chamber is a gap provided between the drum and the heating wall.
Heat exchanger as described in Section. 9. The heat exchanger according to claim 8, wherein the connecting pipe, which is an inlet for the fluid, is located so as to supply the fluid around the drum and into the heating chamber. . 10. A heat exchanger according to claim 9, further comprising cooling means fixed within the drum for cooling the wall of the drum. 11. The heating wall is cylindrical, and the heat exchanger further comprises an internal drum coaxially rotatable within the cylindrical heating wall, and the cooling means is a chamber fixedly located within the internal drum. A heat exchanger according to claim 9. 12. A heating method comprising the steps of circulating a heat exchange fluid of the heating wall soil through a power chamber extending along the heating wall, and heating the heat exchange fluid so that a heat amount of at least 1.8 W/crn2 is imparted to the heat exchange fluid. , the method further comprises: a) circulating a reserve heat exchange fluid for use in an external circuit; b) preventing the fluid from being overheated and decomposed;
In order to improve the heat exchange between the heating wall and the fluid, the heat exchange fluid is stirred in the heating chamber so that the fluid in the heating chamber is given a flow rate of at least Iom/s. C) maintaining said heat exchanger at a desired temperature by measuring the exit temperature of said exchange fluid from said heat exchanger; A method of heating a heat exchange fluid comprising the steps of: heating or cooling the fluid in said heat exchanger. 13 The heating wall is cylindrical, the heating chamber is formed of the heating wall and a wall of a drum coaxially rotatably attached to the inside of the heating wall, and the heat in the heating chamber is controlled by a spiral provided on the drum. 13. A method as claimed in claim 12 in which the exchange fluid is agitated. 14. The method of claim 13, further comprising scraping the fluid from the surface of the heating wall by rotating the drum. 15. The method of claim 12, further comprising cooling the fluid in the heating chamber proximate to the heating chamber. 16. The method of claim 12, further comprising cooling the fluid by circulating a cooling fluid in close proximity to the heating chamber, and adjusting the amount of heat transferred from the fluid by the cooling fluid.