EP0080428B1

EP0080428B1 - Centralheating installation with two energy sources

Info

Publication number: EP0080428B1
Application number: EP82440039A
Authority: EP
Inventors: Patrick Pinal
Original assignee: Boos, Robert
Priority date: 1981-11-25
Filing date: 1982-11-23
Publication date: 1986-11-12
Also published as: EP0080428A1; AT23626T; FR2517031A1; DE3274292D1; FR2517031B1

Description

The present invention relates to central heating installations.
The installations of the type considered are essentially constituted by a closed circuit of a heat-transfer liquid, generally water, circulating between a centralized heat generator, often with fuel (gas, fuel, etc.) usually called a boiler, and a plurality heating bodies, or radiators, judiciously distributed in the different rooms of the premises to be heated in order to ensure thermal comfort.
The heat transfer fluid is brought up to temperature within the boiler, then gives up part of its calories to the medium to be heated through the radiators, before returning to the boiler, and so on during the entire desired heating period.
It is known to widen the possibilities of using this type of installation by supplementing the single centralized heat source (boiler) with one or more secondary thermal sources, decentralized to the radiators themselves.
We thus manage to transform an installation initially designed for a “single-energy” walk into a “dual-energy” system, simply by incorporating into one or more radiators an autonomous electric heating element directly connected to the source of electric power available nearby in the room to be heated.
Such a modification of the installation provides many advantages which have already been widely mentioned, in particular in French patents No. 1,570,420, 991,956 or 2,351,361, so that the repetition of their detailed description would be entirely superfluous. here.
It will simply be emphasized that the greater flexibility of use thus obtained makes it possible to selectively modulate and precisely adapt the heating to the needs which it has so as to achieve appreciable energy savings without penalizing the thermal comfort of the heated premises.
However, the installations described in the aforementioned documents are not without drawbacks, linked essentially to the lack of taking into account or to an imperfect taking into account of the phenomena of expansion of the volume of heat-transfer liquid confined and heated in situ in the or radiators fitted with an electric heating element.
Indeed, the heating device described in French Patent No. 1,570,420 does not take into consideration the expansion of the heated liquid and isolated from the rest of the circuit by two valves mounted respectively at the inlet and at the outlet of a radiator fitted with an electric heating element fixed longitudinally in the inlet manifold at the bottom.
However, in a central heating installation, the liquid occupies the entire volume offered within each radiator and it can be seen that the usual pressure of 2-3 bars under normal conditions (circuit pressure) rises rapidly with the temperature above 10, or even 15 bars, when the heated volume is isolated from the rest of the circuit.
It is therefore understood that the known device is not without presenting a certain danger due to the risks of overpressure, which cannot compensate for a thermal regulation as elaborate as it is, due to a failure which is always possible.
The electric water radiator described in French patent 991 956, provides an atmosphere expansion vessel mounted externally at the end of the upper manifold.
Such a device seems well suited as an individual heating appliance, but serious drawbacks appear when it comes to incorporating it into a central heating installation.
Indeed, due to the presence of the expansion tank open to the outside, it can only be placed at the upper extreme level of the central heating installation.
In addition, it is the heat transfer fluid itself which serves as a heating resistance and has, for this purpose, a composition which makes it unsuitable for being able to be used in conventional central heating installations.
Furthermore, French patent 2,351,361 takes into account the expansion of the liquid within the radiators fitted with electric heating, by means of a collective closed expansion vessel, provided on the general circuit of the heat transfer liquid.
It follows that a provision of this type must be designed in new installations specially adapted for this purpose and cannot be applied, with a reasonable cost, to existing central heating installations.
In addition, the volume of fluid within the heating radiator being necessarily connected to the rest of the circuit to allow expansion, the benefit of a selective calorific contribution is lost since it is impossible to make the heating of each radiator independent.
The object of the present invention is to avoid the drawbacks of the aforementioned known solutions.
It aims in particular to be able to make completely independent within a central heating installation, the proper heating of each radiator equipped with an electric heating element, and this under optimal conditions of operation of the installation and comfort and safety for the user.
With its objectives in view, the invention relates to a dual-energy central heating installation comprising a closed circuit of a heat transfer liquid circulating between a central boiler and a plurality of radiators distributed in the premises to be heated, installation according to which, at least one radiator is internally equipped with an electric heating element placed in the collector at the bottom of the radiator, and characterized in that said radiator comprises, in its collector, at the top, an expansion compensation device having an elastically deformable wall delimiting an internal chamber immersed in the heat transfer liquid and provided with means of communication of its volume with the environment external to said radiator.
In one embodiment, the external medium is the ambient atmospheric medium of the room where the radiator is placed, the pneumatic chamber then being open to the atmosphere.
According to another variant, the deformable wall defining the chamber is a wall made of flexible and hard material shaped like an "accordion" bellows.
According to a preferred embodiment, this wall is made of flexible plastic material in which are embedded metallic filaments.
In accordance with another preferred embodiment, the expansion compensation device also incorporates a calibrated purge for automatically venting the interior volume of the radiator. r.

la figure 1 représente, vu de face et en coupe partielle, un radiateur d'une installation de chauffage central équipé des moyens selon l'invention,
la figure 2 est une vue en coupe longitudinale de l'élément chauffant électrique équipé d'un thermostat mécanique,
les figures 3 et 4 sont des schémas montrant respectivement l'élévation de température dans le temps et le courant de chauffe utilisé pendant la même période,
la figure 5 est une coupe longitudinale de l'élément chauffant électrique dans une variante à thermostat électronique,
la figure 6 est le schéma électrique associé à l'élément représenté sur la figure 5,
la figure 7 est une vue en coupe longitudinale du dispositif à paroi déformable selon l'invention,
la figure 8 est une vue en coupe longitudinale de l'élément chauffant électrique dans une autre variante de réalisation destinée aux radiateurs plats ou extra-plats.

FIG. 1 represents, seen from the front and in partial section, a radiator of a central heating installation equipped with the means according to the invention,
FIG. 2 is a view in longitudinal section of the electric heating element fitted with a mechanical thermostat,
FIGS. 3 and 4 are diagrams respectively showing the rise in temperature over time and the heating current used during the same period,
FIG. 5 is a longitudinal section of the electric heating element in a variant with an electronic thermostat,
FIG. 6 is the electrical diagram associated with the element shown in FIG. 5,
FIG. 7 is a view in longitudinal section of the device with a deformable wall according to the invention,
Figure 8 is a longitudinal sectional view of the electric heating element in another alternative embodiment for flat or extra-flat radiators.

In all of your figures, the same elements are designated by identical references.
As can be seen in FIG. 1, the central heating radiator 1 shown comprises a lower collector 1a and an upper collector 1b connected by a curtain of parallel tubes 1c.
The lower manifold 1a is equipped with an electric heating element 2 mounted at the end opposite to that of the inlet E of the heat transfer liquid.
The outlet manifold 1b is provided, for its part, with the expansion compensation device 3, mounted in place of the usual bleed screw, opposite the outlet pipe S of the heat transfer liquid.
Two solenoid valves R 1 and R 2 are placed respectively on the input E and on the output S to isolate the volume of liquid in the radiator from the rest of the circuit (not shown) when the electric heating element 2 is activated.
This comprises an internal part to the collector 1a, composed of a heating resistor 6 placed above a temperature probe 7, and an external part comprising the thermal regulation protected by a cover 46, from which a connecting cord comes out. electric L.
The resistor and the probe are fixed to a support 27 which internally carries the thermal regulation and on which the cover 46 fits.
This support constitutes a threaded plug at its end 4 so that it can be tightly screwed into the drain hole of the manifold 1a.
The expansion compensation device 3 comprises a deformable rigid wall 32 defining an internal pneumatic chamber 48 immersed in the heat transfer liquid of the upper collector 1b.
This wall is held by the threaded end 49 of a sleeve 50 which is screwed into the bleed orifice of the upper manifold.
The sleeve 50 internally contains a venting valve of which only the bleed screw 36 is visible in the figure.
As will be understood, the electric heating element 2 is presented in a compact block which it suffices to connect to the electric network by the cord L to obtain a rise in temperature of the liquid contained in the radiator to the desired value. and to regulate it by the thermostat.
Furthermore, the expansion compensation device 3 comprises a pneumatic chamber 48 immersed in the liquid and which, by variation in volume following a deformation of its wall 32 as a function of the pressure inside the radiator, ensures a constant mass heat transfer liquid.
In addition, this variable chamber makes it possible to avoid noises during the convection of the liquid in the event of excess air.
The heating element and the expansion compensation device are both provided, as already said, with a standard threaded plug so that they can be installed on an existing radiator, for example.
To do this, after closing the inlet valves R 1 and outlet R 2 , the drain plug of the lower manifold 1a as well as the drain plug on the upper manifold 1b are removed.
After the radiator has been completely emptied, the thermostatically controlled heating block 2 is mounted in place of the drain plug and the device 3 in place of the drain plug.
After reopening the valves R 1 and R 2 for filling the radiator, the latter thus equipped is again in normal operating state within the central heating installation. We proceed to the electrical connection to the socket nearest voltage using the standard cord plug L.
To carry out the commissioning of the system according to the invention, it is advantageous to isolate the volume of liquid from the radiator by closing the valves R, and R 2 .
The operation is carried out by rotation of the graduated control button 5 (Figure 2 or 5) to the position corresponding to the value of the desired temperature for the heat transfer liquid (approximately 30 to 90 ° C).
The heating resistor 6 enters into service and raises the temperature of the radiator until the thermostat set by button 5 is triggered, which takes place when the set value is reached.
Figures 2 and 5 show two different variants of the thermostat of the heating element, mechanical and electronic respectively.
In the case of the variant with a mechanical thermostat (Figure 2), the heating of the liquid causes the probe 7, which consists of a stainless steel tube 4 mm in diameter, to lengthen.
The latter is secured at its end to an internal rod 8 with a diameter of 2.5 mm in material having a coefficient of expansion substantially lower than the tube of the probe 7.
The lengthwise expansion of the latter thus causes the rod 8 to be driven, which in turn causes its other end to pull the support 9 of a rocker spring 11.
The support 9 acts on an insulating material stop 10 by means of the rocker 11, which itself actuates a rocking contact 12. When the tensile force exerted by the rod 8 reaches the rocking value of the rocking contact support 12, it changes state and interrupts the passage of the heating current Ir (fig. 4).
As the resistor 6 is no longer in service, the liquid from the radiator cools by heat exchange with the ambient medium.
When the temperature of the liquid reaches a difference value at Tp (FIG. 3), from 5 to 10 ° C, for example, lower than the reference value designated in 13, the rise of the rod 8 causes a reversal of the movement of the support contact 12 which then restores the flow of current through the upper contact 14.
The regulation on AT 2 is thus carried out over time, and the diagram of FIG. 4 shows the states of passage of the current Ir in correspondence with the regulation curve of FIG. 3.
The reference for obtaining an adequate range Af i of the thermostat is made by the value of the thread pitch of the control button 5 and by the adjustment of the height positioning of the needle 16 which presses on the support 9 of the rocker spring 11.
The positioning at reference zero is obtained by a small stop spring 17 which cooperates with a rotary cam 18 fixed to the needle 16 for the angular adjustment of the control 5.
A helical spring 19, working in compression, ensures the return of the support 9 for operation of the rocker spring 9 to a value of approximately 4 kgf, for example.
The fixing of different parts is ensured by rivets, only one of which has been shown at 31 so as not to unnecessarily overload the figure.
In the case of the variant with electronic thermostat shown in FIGS. 5 and 6, the heating of the probe 7 is transmitted by contact to a thermistor 20 embedded in the end of the latter.
The decrease in the CTN value (negative temp coeff.) Modifies the current and the voltage of the bridge formed by resistors 21 and 22, causing, via the integrated circuit 23 of type MFC 8070, the change of state. ordering a triac 24.
This, as seen in FIG. 5, is fixed by a screw 43 on a cooling plate with fins 44 and the temperature is maintained by air circulation through orifices 45 provided on the cover 46.
When the value of setpoint 13 (see Figure 3) set by the. potentiometer 25 (Figures 5 and 6) is reached, the regulation of the heating resistor 6 starts and can be visualized by an indicator light 26.
The electrical connections inside the cover 46, covering the plastic plug 27, are made by standardized plug-in lugs 28 and plugs 47.
The shielded resistor 6 and the thermal probe 7 ′ are sealed by two O-rings 29 and 29 ′ compressed by a support core 30 of elastomer force-fitted.
We will now describe, with reference to FIG. 7, an embodiment of the expansion compression device according to the invention.
As already said, this device 3 essentially comprises a resistant but deformable wall 32, shaped like an "accordion type" bellows and internally defining a pneumatic chamber 48. This wall is held in a body 50 serving as a plug-thanks to its threaded anterior bearing 41 which is screwed into the bleed orifice of the upper manifold of the radiator (not shown in Figure 7).
The tightness of the assembly is ensured by crushing the end of the wall 32 by means of a core 42 inserted by force which is pierced longitudinally by a channel 33 putting the chamber 48 in communication with the external atmosphere.
Advantageously, the threaded surface 41 also has a channel for placing the interior enclosure of the radiator in communication with the exterior at its upper end.
This channel 51 extends into the body 50 and opens into an internal cavity 52 comprising an orifice 35 with the outside, normally closed by a bleed screw 36.
After opening thereof, the orifice 35 has the conventional role of evacuating the air occasionally present in the radiator.
In the center of screw 36 is a ball 37 compressed by a spring 38 calibrated by a hollow screw 40 and which plays the role of overpressure safety. The seal is ensured by the O-ring 41.
In parallel with the operation of the thermostate heating block 2 seen above, the expansion chamber 48 during the rise in temperature compresses under the pressure of the liquid and the excess air is evacuated through the passage 33.
The consistency and shape of the wall 32 are defined to allow a modification of the volume of the chamber 48 in order to compensate for the effects of the expansion of the liquid and thus maintain a constant mass of liquid in the radiator by avoiding overpressures.
To this end, the wall 32 may be made of flexible plastic material in which are embedded metallic filaments 34 which give it the desirable mechanical strength.
In another embodiment, the wall can be made of stainless steel, therefore resistant to corrosion.
As a variant, the inlet R 1 and outlet R 2 valves can be manual or electrically controlled, subject to the commissioning of the heating block 2, when the button 5 is operated.
In addition, it should be understood that these valves are not strictly essential for the implementation of the invention. Their presence is however an important advantage, since they allow, by cutting the liquid mass of the radiator from the rest of the circuit, to avoid heat loss by convection within the circuit, outside the place that is desired specifically heat.
Furthermore, the heating block 2, like the device 3, are perfectly adaptable to all types of radiator. If necessary for a larger diameter of the radiator orifices, a threaded sleeve inside and outside will ensure adaptation.
In the case of modern extra-flat radiators, it is possible that the lower collector cannot receive, for reasons of space availability, a linear heating resistor, very elongated and extending along a large part of the collector, as shown in the previous figures.
To ensure equal heating power, it is then possible to modify the shape of the resistor and jointly opt for the option with electronic thermostat, in accordance with another alternative embodiment of the invention shown in FIG. 8.
According to this variant, the heating resistor 6 ′ is shaped as a “U between the branches of which the probe 7 ′ is placed to reduce the overall dimensions in width.
The resistor and the probe are held at their ends in a plastic washer 53 and the resistance is held by a spacer 54 placed between its two branches.
This also serves as an introduction guide, avoiding, by virtue of two lateral protrusions 55, the coming into contact of the resistance tube with the internal wall of the collector a.
This sub-assembly is placed in the threaded anterior surface 4 ′ of the body 27 ′, hollowed out for this purpose and having an oblong opening 56 for the passage of the resistance and the soda.
The assembly is carried out by tightening the support washer 53 on an O-ring seal 57 using a tubular core 58 screwed into the threaded front part 4 'and providing a central passage for the electrical connection wires 59 resistance and 60 of the probe.
The assembly is finally attached by screwing onto the radiator by means of a threaded sleeve 61 welded into the receiving opening of the manifold a.
As will no doubt already be understood, the invention is perfectly suited to the field of energy savings, in particular as an extension of those which consist in reinforcing the insulation of buildings.
Indeed, after having improved the thermal insulation of an individual house for example, so that it meets the conditions recommended for integrated electric heating, the installation of the system according to the invention makes it possible to choose the mode heating (electric or based on the old fuel), in all seasons and as needed, either as an addition to one or more radiators, or as generalized heat input for the entire central heating installation .

Claims

1. A central heating installation with two energy sources comprising a closed circuit of a heat transfer liquid circulating between a boiler and a plurality of radiators distributed over the various parts of the building to be heated, according to which installation at least one radiator is equipped with an electrical heating element (2) disposed in the lower collector of the radiator, said installation being characterized in that said radiator comprises in its upper collector (1 b) means for compensating thermal expansion (3) including an elastically deformable wall (32) limiting an inner chamber (48) immersed in the heat transfer liquid and provided with means (33) for causing its volume to communicate with the surroundings outside said radiator.

2. The installation according to claim 1, characterized in that the means for compensating thermal expansion (3) incorporates venting means (35, 36, 51) causing the upper collector (1b) to communicate with the outer ambient surroundings.

3. The installation according to claim 1, characterized in that the deformable wall (32) is formed like an accordeon-type bellows.

4. The installation according to claims 1 or 3, characterized in that the deformable wall (32) is made of plastic material interspersed with metallic filaments (34).

5. The installation according to claims 1 or 3, characterized in that the deformable wall (32) is made of stainless steel.

6. The installation according to claim 1, characterized in that said radiator has, at the inlet (E) and at the outlet (S) for the heat transfer liquid, a valve (R, and R₂) which ensures that the volume of liquid contained in the radiator is isolated from the rest of the heating circuit.

7. The installation according to claim 6, characterized in that the valves R, and R₂ are elec- trovalves whose activation is controlled by the putting into service of the electrical heating element (2).

8. The installation according to any of the above claims, characterized in that the electrical heating element (2) includes a mechanically ther- mostatted temperature sensor (7).

9. The installation according to any of the above claims, characterized in that the electrical heating element includes an electronically ther- mostatted temperature sensor (7').

10. The installation according to any of the above claims, characterized in that the electrical heating element includes a heating resistor (6') having a U shape between the branches of which the temperature sensor (7') is disposed.