FR2809276A1 - THERMOPLONGER FORMING DEVICE THAT CAN BE USED IN PARTICULAR IN A WATER CIRCULATION HEATER - Google Patents

Abstract

The thermal insert consists of a heating cartridge (3) within a sealed tube (1) which contains a heat carrying liquid (2). The cartridge includes a resistor (5), thermal cut-out (8) with parallel resistor (9) to maintain a cut-out operation until water circulation is restored and a fuse (12) to protect against electrical faults An Independent claim is made for a radiator which uses the thermal insert

Description

The present invention relates to a device forming an immersion heater

can be used in particular

  in a water circulation heating radiator.

  The French patent application published under No. 2,777,410 in the name of the applicant describes such a device comprising a collector in the form of a tube closed in leaktight manner at its two ends and containing a heat transfer liquid to be heated and housed in the collector by bathing in the heat-transfer liquid, a waterproof heating cartridge with an internal heating electric resistance embedded in the cartridge by being

  electrically isolated from the latter.

  This device is generally placed vertically in a collecting tube of a water circulation heating radiator, such as for example a towel radiator, thereby heating the water in this radiator. Sometimes, for special reasons, the water no longer circulates through a radiator, for example due to a fault in the pump

water supply.

  The absence of water in the radiator causes the immersion heater device to overheat, which can

go to its destruction.

  The object of the present invention is to eliminate the above drawback by proposing a device forming a self-heating immersion heater at a determined temperature below a superheating temperature by

  if there is no water in the radiator.

  For this purpose, according to the invention, the device forming an immersion heater, of the type comprising a collector in the form of a tube closed in leaktight manner at its two ends and containing a heat transfer liquid to be heated and, housed in the collector while immersed in the heat transfer liquid. , a waterproof heating cartridge with internal heating electrical resistance embedded in the cartridge being electrically isolated from this

  last, is characterized in that it comprises a cutter

  thermal circuit housed in the collector in a leaktight manner by being electrically isolated from the heat-transfer liquid and connected in series with the electric heating resistor by occupying a normally closed position for supplying this resistance with electric current, the thermal circuit breaker being able to open when the coolant is abnormally heated to a temperature equal to or greater than one

predetermined threshold value.

  Preferably, the immersion heater device further comprises an electrical resistance connected in parallel to the thermal circuit breaker and allowing the passage of an electric current through the electric heating resistance when the thermal circuit breaker is open and of a value ensuring the heating the heat transfer liquid to a holding temperature of the

  thermal circuit breaker in open position.

  The temperature at which the circuit breaker is kept in its open position is lower than the predetermined threshold temperature. In addition, the thermal circuit breaker is brought back to the closed position by disconnecting the electric heating element from its power source until

  the coolant has cooled down.

  Preferably, the thermal circuit breaker is

consisting of a bimetallic strip.

  Advantageously, the thermal cut-out and the electrical resistance in parallel are housed in a

  waterproof housing integral with the cartridge.

  The device further comprises a fuse connected in series with the heating resistor and housed in the housing of the thermal circuit breaker and of the resistor.

parallel electric.

  The invention also relates to a water circulation heating radiator, such as for example a towel radiator, and which is characterized in that it is equipped with an immersion heater device such as

previously defined.

  The invention will be better understood and other aims, characteristics, details and advantages thereof

  will appear more clearly in the description

  Explanatory which will follow made with reference to the appended schematic drawings given solely by way of example illustrating an embodiment of the invention and in which: - Figure 1 is a view in longitudinal section of the device forming an immersion heater of the invention; FIG. 2 represents the electrical diagram of the device forming an immersion heater with thermal circuit breaker according to the invention in the normally closed position; and - Figure 3 is a view of the electrical diagram of Figure 2 o the thermal circuit breaker is maintained in the open position due to overheating of the device

forming immersion heater.

  The device forming an immersion heater will be described in the application to a water circulation heating radiator, such as for example a towel radiator, in which it is integrated to heat the circulating water, but it is understood that '' it can be used for other different applications

  requiring the heating of a liquid or a fluid.

  Referring to the figures, the device forming an immersion heater comprises a manifold 1 in the form of a metallic cylindrical tube closed in leaktight manner at its two ends and containing a heat-transfer liquid to be heated 2, which can be electrically insulating and consisting of mineral oil , preferably of the parafinic type with a high viscosity index. For example, the mineral oil is that of the company SHELL marketed

  under the name "SHELLFLEX" type 110 FC.

  The device further comprises, housed in the collector 1 while immersed in the heat transfer liquid 2, a heating cartridge 3 making it possible to heat the heat transfer liquid 2 to bring the water from the radiator to a determined temperature. The heating cartridge 3 consists of a metallic cylindrical tube 4 in which there is an internal heating electrical resistance 5 embedded in magnesia M compacted in the tube 4 in order to electrically isolate the resistance 5 from the tube 4. The resistance 5 can be consisting of a conductive wire wound in a spiral with contiguous turns or not, having substantially the shape of an elongated U so that these two free ends leaving the tube 4 are respectively connected to two external conductive wires

supply 6.

  The heating cartridge 3 is fixed in the collector 1 substantially coaxially thereto by having one of its floating free ends and its opposite end secured to a support sleeve 7 made of an electrically insulating material fixed to

  through one of the end walls of the manifold 1.

  The support sleeve 7 comprises an externally threaded cylindrical part 7a for engaging in a corresponding tapped hole lb passing through the end wall 1a of the manifold 1 and a flange part 7b coming to bear on the external face of the wall end la when the support sleeve 7 is locked by screwing into the wall la. This sleeve further comprises a cylindrical end 7c in which is joined, by welding or gluing, the corresponding end of the heating cartridge 3. The supply wires 6 connected to the two ends of the heating resistor 5 pass through an internal bore of the support sleeve 7 for projecting outside the

collector 1.

  The immersion heater device described so far conforms to that described in the application for

  French Patent No. 2,777,410 mentioned previously.

  According to the invention, the device forming an immersion heater further comprises a circuit breaker or thermal switch 8 housed in a sealed manner in the collector 1 by being connected in series with the electric heating resistor 5. The circuit breaker 8 is preferably constituted by a bimetallic strip shown in FIGS. 2 and 3, occupying a normally closed position for supplying electric current to the heating resistor 5 and capable of opening when the heat transfer liquid 2 is brought to an abnormal temperature of overheating greater than or equal to a value of predetermined threshold. An electrical resistor 9 is connected in parallel to the thermal circuit breaker 8 and allows the passage of an electric current through the heating resistor 5 when the thermal circuit breaker 8 is open. Resistor 9 has an ohmic value ensuring the passage of a current allowing the heating of the liquid

  coolant 2 at a cut-off holding temperature

  thermal circuit 8 in open position, this holding temperature being lower than the temperature

of predetermined threshold.

  The circuit breaker 8 and the resistor 9 can be housed in a sealed housing 10 embedded in the heat transfer liquid 2 and secured to the tube 4 of the cartridge 3 by coaxially extending the latter. The housing 10 can be fixed for example by welding to the tube 4 of the cartridge 3 with the presence of a transverse partition wall 11 between housing 10 and tube 4, the wall 11 being provided with two holes for passage of the

  heating resistance 3 for its connection with the cutter

  circuit 8 and the parallel resistor 9.

  A fuse 12 is connected in series with the circuit breaker resistor 8 and, as is known in the field of water circulation heaters, a thermostat 13 is also connected in series with the fuse 12. The latter and the thermostat 13 can be accommodated in the

housing 10.

  The circuit breaker 8 and the parallel resistor 9 can be encapsulated in a small housing 14 housed in the housing 10. The operation of the device forming

  immersion heater already results from the description which has

  been made above and will now be explained.

  In normal operation, according to which the radiator is filled with water, the thermal circuit breaker 8 occupies its closed position shown in FIG. 2 and the radiator normally heats the ambient environment with adjustment of the heating temperature using the thermostat. 13. For example, the normal heating temperature of the immersion heater device can be fixed at approximately 80 C for a nominal electrical power of the

  electrical resistance 5 of approximately 900 Watts.

  During abnormal operation resulting from the absence of water in the radiator, the thermal circuit breaker 8 will open from a predetermined threshold temperature of the immersion heater, for example from 150 C, as shown in FIG. 3, and the resistor 9 then lets a current flow, for example of a few milliamps, which corresponds to a determined temperature value lower than the threshold temperature reached above, to maintain the circuit breaker in the open position 8. For example, the ohmic value of the resistor 9 can be established so that the thermal circuit breaker is maintained in the open position at a temperature of the order of 100 to 110 ° C. preventing this circuit breaker from closing. thermal. Once this abnormal operation has been detected by the user, the latter disconnects the immersion heater device from its power source until the circuit breaker 8 closes again after a few minutes after the coolant 2 has cooled down while

  the user puts water back into the radiator.

Claims (9)

  1. Device forming an immersion heater comprising a collector (1) in the form of a tube closed in leaktight manner at its two ends and containing a heat transfer liquid to be heated (2) and, housed in the collector (1) while immersed in the heat transfer liquid (2 ), a waterproof heating cartridge (3) with internal heating electrical resistance (5) embedded in the cartridge (3) being electrically isolated from the latter, characterized in that it comprises a thermal circuit breaker (8) housed in the collector (1) in a leaktight manner by being electrically isolated from the heat transfer liquid (2) and connected in series with the electric heating resistor (5) in a normally closed current supply position   electrical resistance (5), the cut-out   thermal circuit (8) which can open when the heat transfer liquid (2) is abnormally heated to a temperature equal to or higher than a threshold value predetermined.   2. Device according to claim 1, characterized in that it further comprises an electrical resistance (9) connected in parallel to the thermal circuit breaker (8) and allowing the passage of an electric current in the   electric heating resistance (5) when the   thermal circuit (8) is open and of a value ensuring the heating of the heat transfer liquid to a temperature for maintaining the thermal circuit breaker (8) in the open position. 3. Device according to claim 2, characterized in that the temperature for maintaining the thermal circuit breaker (8) in the open position is lower than the   predetermined threshold temperature.   4. Device according to claim 2 or 3, characterized in that the thermal circuit breaker (8) is brought back to the closed position by disconnecting the electric heating resistor (5) from its power source until the heat transfer liquid (2) has cooled down.   5. Device according to one of claims   above, characterized in that the thermal circuit breaker (8) consists of a bimetallic strip.   6. Device according to one of claims   above, characterized in that the thermal cut-out (8) and the electrical resistance in parallel (9) are housed in a sealed housing (10) integral with the cartridge (3).   7. Device according to claim 6, characterized in that it comprises a fuse (12) connected in series with the heating resistor (5) and housed in the housing (10) of the thermal circuit breaker (8) and of the resistor parallel electric (9).   8. Device according to one of claims   above, characterized in that it is arranged in a water circulation heating radiator, such as by   example a towel radiator.   9. Heating radiator with water circulation, such as for example a towel radiator, characterized in that it is equipped with an immersion heater device as defined in any one of claims 1 to 8.