Device for preheating a fluid, in particular coolant for a combustion engine

Abstract

The invention relates to a device for heating a fluid (2), comprising a heating body (4) having a through passageway (6, 8) for the fluid and provided with at least one groove (14) on its outer surface; at least one electrical resistance (24) housed in the at least one groove (14) of the heating body. The device further comprises at least one closure plate (20) of the at least one groove (14) overlying the at least one resistance (24).

Claims

1. A heating device for heating a fluid, comprising: a heating body having a through passageway for the fluid with: a plurality of parallel longitudinal channels; at least one groove formed on an outer surface of the heating body, said outer surface extending along the plurality of parallel longitudinal channels; at least one electrical resistance housed in the at least one groove of the heating body; and at least one closure plate of the at least one groove overlying the at least one electrical resistance and extending along the plurality of parallel longitudinal channels and extending transversely, in each of two opposed transverse directions, beyond the groove so as to have two lateral edges in direct contact with the body, wherein each of the two lateral edges is fastened to said body by fastening screws at said lateral edge; wherein the passageway passing through the heating body comprises: a transverse channel formed in the heating body at each of both ends of the plurality of parallel longitudinal channels, ensuring at each of said both ends a direct connection of all of said plurality of parallel longitudinal channels.

2. The heating device according to claim 1, wherein the width of the at least one groove is greater than the height of said at least one groove on a majority of the length of said at least one groove.

3. The heating device according to claim 2, wherein a ratio between the width and height of the at least one groove is greater than 3.

4. The heating device according to claim 1, wherein the at least one electrical resistance is elongated and flat.

5. The heating device according to claim 1, wherein the at least one closure plate bears on the heating body.

6. The heating device according to claim 1, wherein the at least one closure plate comprises: orifices along the lateral edges of said at least one closure plate and the heating body comprises: threaded bores for receiving the fastening screws of the fixation by screwing, said fastening screws being arranged through said orifices.

7. The heating device according to claim 1, wherein the at least one closure plate is in contact with the at least one electrical resistance.

8. The heating device according to claim 1, wherein the passageway passing through the heating body is straight.

9. The heating device according to claim 1, characterized in that the at least one groove and the at least one electrical resistance extend transversely over all of the plurality of longitudinal channels.

10. The heating device according to claim 1, wherein each of the transverse channels is produced by drilling.

11. The heating device according to claim 1, wherein the plurality of longitudinal channels and the body are formed by extrusion and the at least one transverse channel is formed by removing material.

12. The heating device according to claim 1, wherein the heating body is an integral solid block that is parallelepipedic.

13. The heating device according to claim 1, wherein: the at least one groove comprises two grooves on opposite sides of the heating body, the passageway extending between said opposite sides and said two grooves.

14. The heating device according to claim 1, wherein the at least one electrical resistance is a PTC heater.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a representation of the transverse face of the heating device according to the invention.

(2) FIG. 2 is a sectional view II-II of the heating device of FIG. 1.

(3) FIG. 3 is a view of the longitudinal side, on the side of the plugs, of the heating device of FIGS. 1 and 2.

DESCRIPTION OF EMBODIMENTS

(4) The fluid heating or preheating device shown in FIGS. 1 to 3 essentially comprises a solid member 4 of generally rectangular section having a through passageway for the fluid. The passageway comprises three straight and parallel channels 6 passing through the block from side to side. These channels are preferably produced by drilling.

(5) The passageway also comprises two transverse channels 8, each being near one of the two ends of the longitudinal channels 6. These channels have the function to ensure a placing in communication of the longitudinal channels. These transverse channels are preferably made by drilling.

(6) The heating body 4 can be made by extrusion with the longitudinal channels. The transverse channels can then be made by machining.

(7) The longitudinal channels 6 open out on the front and back of the body 4. The areas of these faces where the lateral channels open are fitted with plugs 12, while the areas of said faces where the central channel opens are provided with fittings or connectors 16 for a hydraulic or gas connection of the device. These fittings may in particular be of the type with hose barb for engaging a hose by insertion. The plugs 12 and/or fittings 16 are preferably of the type with external thread cooperating with a female thread formed in the body 4.

(8) The transverse channels 8 open only on one of the side faces of the body 4. The areas of said face where these channels open are provided with a plug 10. The plugs 10 are preferably of the type with a male thread cooperating with female thread formed in the body 4.

(9) The body 4 comprises two grooves 14 on the longitudinal sides of the body 4 extending along the longitudinal channels 6. The grooves 14 have a width substantially greater than their height, for example in a ratio greater than 2, preferably 3 more preferably 5. Each groove 24 accommodates an electrical resistance generally flat and extended. A closure plate 20 covers each of the grooves 14 and the corresponding resistance. Each of the resistances 24 covers, along the width of the body, all of the longitudinal channels 6. They also cover them substantially completely along the length of the body 4.

(10) Each of the two plates 20 extends transversely beyond the groove so as to have its lateral edges (corresponding to the longitudinal direction of the device) in contact with the body 4. To that end, orifices 22 are provided therein for receiving fastening screws (not shown) engaging with corresponding threaded bores 18 of the body 4.

(11) The electrical resistances used as of the PTC type (Positive Temperature Coefficient acronym). Depending on the temperature, a balance between the thermal flux generated by the PTC resistance and the heat dissipation to the environment is created. Heat dissipation is maximized by the provision of electrical resistances along the fluid passage, the temperature of the ceramic component of the PTC resistance will decrease which will ensure to increase the electrical power via an increase of the current intensity. The power absorbed by the fluid is dependent on the ambient temperature, the fluid temperature and the flow rate of the pump circulating the fluid.

(12) The PTC electric resistances can run dry without risk of breakdown. Without thermostat and security, they will automatically stabilize at their set point temperature. In addition, these resistances can operate by being supplied with different voltages (110-240 V) and frequencies (50-60 Hz).

(13) The PTC electric resistances have the advantage that they can be heated without regulation thermostat without causing breakdown, as would be the case for shielded heating elements standard type. In addition, the PTC, electric resistances are used to withstand cold and hot electrical insulation tests whereas standard electrical resistances are normally tested in cold conditions as they can deteriorate in hot conditions.

(14) The PTC electrical resistances are self-regulating resistances, which increases the load per unit area without the risk of overheating.

(15) Compared to a standard electrical resistance, and for the same power, the bulk volume of the PTC electrical resistance is nearly 80% lower. This significant reduction in volume allows the use of elongated electric resistance and flat and insert them at the solid element of the heating device or preheating described above.

(16) In order to guarantee minimal heat dissipation, a cap having a thermal insulation may be provided. It may cover the body of the device and is secured thereto by connecting means which have been disposed on the longitudinal ends of the body.

(17) The heating body is in the form of a rectangular parallelepiped. It can be made of aluminum, brass, stainless steel or other conductive material of the heat, depending on the intended application.

(18) The internal volume of the solid element has been shaped so as to accommodate different channels, favoring the passage of fluid according to a predominantly longitudinal direction while maximizing the heat exchange with the PTC electrical resistances through the presence of several longitudinal channels communicating with each other via transverse channels.

(19) With regard to combustion engines and, in particular for vehicles and generators, one or more PTC electric heating resistances are placed within the body and are powered by the battery 12 or 24 VDC which allows, depending the application to continue the heating when the device is no longer supplied with 110-230 V. These combustion engines or these generators, thus continue the heating, which allows the engine to reach faster to temperature ideal operation.

(20) Depending on the various applications and fluid to be heated, the circulation pump is adapted.