ES1215409U - Thermostat with removable calibration locking means - Google Patents

Abstract

The object of the present invention is a thermostat (1) having calibration locking means that may be unlocked at user discretion, in order to increase the performance of the water heater whereon said thermostat (1) is installed. Said locking means consist of joining elements (7.41) fracturable as a result of the application of a rotational force on the adjustment knob (7, 7.1) by which the operating temperatures of such thermostat (1) are calibrated. Said adjustment knob (7, 7.1) is also provided with visual and/or sound identification means (7.10, 7.40) in order to facilitate the user in the task of recovering the calibration point T.box initially preset, even after the fracture of said joining elements (7.41).

Description

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DESCRIPTION

Thermostat with removable calibration locking means.

The object of the present invention is a thermostat provided with means for blocking the calibration that the user can remove at discretion.

The present invention relates to the field of devices for safety control and temperature adjustment of a heating apparatus, in particular an electro-propelled accumulation water heater but, in general, any domestic appliance, such as Dishwasher and washing machines.

For a complete description of the prior art of said devices (which we will hereinafter generically refer to as "thermostats") reference will be made to the content of the previous patents EP 0651412, EP 1652017 and WO 2012/014025 in the name of the same applicant of this patent.

That is why it is sufficient to briefly describe the characteristics of a possible type of thermostat, referring to what is illustrated in Figure 1 which represents a thermostat according to the prior art.

The numerical reference 1 'indicates the thermostat as a whole, which comprises a containment box 2' defined by a base 2.1 'and a cover 2.2'.

The numerical reference 3 'indicates a thermosensitive element that extends externally from the base 2.1' to the environment to be controlled (specifically, the tank of a water heater).

According to the prior art, said thermosensitive element 3 'can comprise a thermally expandable tube and good heat conductor, which performs the function of mechanical actuator of the internal contacts of the thermostat 1', cutting or restoring the power supply to the elements heaters (electrical resistors, not shown in the figure) by a known kinematic mechanism.

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An actuating element (not shown in the figure) is also generally in the vicinity of said thermosensitive element 3 ', in a tray arranged at the base 2.1', intended to perform the function of thermal protection and normally comprising a bimetallic element bistable, suitable for causing the thermostat contacts to open when a predetermined temperature is reached by known return kinematic means.

The reference number 4 'indicates the external connection terminals for the power supply of the entire thermostat 1', by means of which power is also supplied to optional accessory devices (such as, for example, light indicators or acoustic alarms) connected through of the coupling holes 5 '.

In the cover 2.2 'of said thermostat 1' there is an adjustment button 7 'which has a suitable indicator 7.1' for the initial calibration of the thermostat 1 'and the subsequent optional temperature variations that are intended to be fixed.

The type of thermostat 1 'described above is only one of the possible ones, but what matters for the purpose of the present invention is that the temperature adjustment button 7' normally comprises in a ring coupled to an underlying knurled ring nut, the rotation of which It allows adjusting the thermostat calibration temperatures, according to the type of water heater and the particular needs of the market to which the product is intended.

Generally, said calibration temperatures coincide with at least the following two operating conditions of the thermostat:

- a standard temperature (at which from now on we will abbreviate "T.perf") by means of which the value is set to obtain the intended performance with respect to the hot water available to the user;

- a maximum safety temperature (referred to hereinafter as "T.max"), beyond which the thermostaton must operate for safety reasons: this condition is normally set by defining a end point of travel, against which indicator 7.1 hits

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A technician (or, less frequently, the user) makes the optional and subsequent variations of said calibration temperatures, acting directly on the indicator 7.1 'of the adjustment button 7.' or acting on indirect means associated with said indicator 7.1 ', such as an additional button provided in the control and management interface of the water heater.

An example of this type can be found in the previous document US n. 2012/0121305, which describes a control button that can be operated to change the standard temperature, preset by the technician or subsequently modified by the user.

Said document describes a mechanism associated with an adjustment button, comprising a connection between a retention tooth and a disc provided with a series of projections, such that said retention tooth is suitable for locking the disc that engages with one of these highlights.

When the user intends to change the previously set temperature, he must decouple the connection between the tooth and the projection of the disc, turn the button to the intended temperature and re-lock the button with the mechanism described above.

The next application of the EU ErP Directive (Energy Related Products, applicable to all appliances for heating and domestic hot water production) and the ELD legislation on Energy Labeling, will reflect the situation just described with respect to 1 'standard thermostat calibration modes.

In fact, with these laws, there will be an obligation for manufacturers to have an energy label that highlights the efficiency class to which the water heater belongs, assessed based on the calibration with which the thermostat leaves the factory: from now on hereinafter referred to as said calibration "T.box".

It is clear that these EU laws cause manufacturers to face the dilemma of what is the optimum thermostat calibration value to combine the growing needs of climate and environmental protection (imposed by the new ErP and ELD Directives ) with higher performance for the end user: in fact, the thermostat calibration to T.perf value (thanks to which the end user obtains

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as much hot water as possible) will negatively influence the energy efficiency class; on the other hand, adjusting its calibration to the lower T.box value to obtain a better energy class will be detrimental to the benefits that the water heater can achieve.

The objective of the present invention comprises avoiding this type of inconvenience, by providing means intended for the initial and subsequent calibration of a thermostat, suitable for combining the opposite needs of energy efficiency and thermal efficiency.

A further objective of the present invention comprises providing means intended for a more precise calibration of the thermostat.

A further objective of the present invention comprises providing means intended to recover the initial calibration.

These and other objectives, which will be clearly shown below, are achieved with a thermostat according to claim 1.

Other objectives can also be achieved through the additional features of the dependent claims.

The additional features of the present invention will be better understood from the following description of some preferred embodiments, according to the patent claims and which are illustrated, by way of non-limiting example, in the accompanying drawings, in which:

- Figure 1 represents a thermostat according to the prior art, as described above, that is, provided with standard calibration means;

- Figure 2 represents an exploded view of the thermostat according to a first variant of the present invention, that is, provided with the innovative calibration means which will be described below;

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- figure 3 represents the mounted thermostat of figure 2, according to a first operating configuration;

- Figure 4 represents a plan view of the thermostat according to the present invention, according to a second operating configuration;

- Figure 5 represents a plan view of the thermostat according to a second variant of the present invention.

The characteristics of a preferred variant of the present invention will now be described with reference to the figures, in particular to figures 2, 3 and 4 related to the distinctive aspects compared to the prior art.

The numerical reference 7 indicates globally the temperature adjustment button, suitable for defining the calibration temperatures of thermostat 1.

Said adjustment button 7, unlike the prior art represented in Figure 1, comprises two distinct elements and, at least initially, separated, that is:

- an inner sleeve 7.3, suitable for coupling with the underlying knurled ring nut 8 which, according to the prior art, must be operated to perform the thermostat 1 calibration, and

- an outer ring 7.2, intended to be coaxially arranged around said inner sleeve 7.3 with the procedures and objects described below.

As mentioned, said inner sleeve 7.3 is the element on which the manufacturer acts to calibrate thermostat 1 at the intended temperature: specifically, according to ErP legislation, said temperature value is equal to T.box, which identifies the temperature at which the thermostat 1 leaves the factory and allows the water heater to maintain a better energy classification (according to the ELD Directive) compared to that obtained in the event that the calibration value is equal to the temperatures T.perf or T.max, as defined above, superior to T.box.

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Normally, said T.box temperature value is what allows thermostat 1 (or, rather, the water heater that implements said thermostat) to reach the minimum energy class required by the ErP Directive, so that there is no an excessive distance, in relation to heat, compared to a prior art thermostat (i.e. not calibrated according to the new energy legislation), calibrated at the highest temperature T.perf.

However, it is not excluded that said temperature value T.box is even lower, so that the energy efficiency class is further improved.

In both cases, to achieve a considerable improvement from the point of view of energy consumption, there is a decrease in the thermal efficiency of the water heater to which the thermostat 1 is applied, which cannot guarantee the availability of hot water in the quantities to those that the user was accustomed with the thermostats that were used before the recent EU legislation.

The adjustment button 7 of the present invention avoids this inconvenience, in particular thanks to the peculiarity of the outer ring 7.2.

According to the preferred variant, said outer ring 7.2, arranged around the inner sleeve 7.3 with which it is coupled with a rotating assembly, is in fact previously welded with the cover 2.2 of the thermostat 1 and, once the calibration of the thermostat 1 has been completed up to the T.box value by means of said inner sleeve 7.3, it is attached to the latter by means of known fixing means, such as laser welding or adhesive bonding (for example, cyanoacrylate or UV ultraviolet adhesive).

Therefore, said outer ring 7.2 constitutes a blocking means that guarantees the retention and maintenance of the T.box calibration value of the thermostat 1 (with the consequent obtaining of the energy efficiency label resulting from said calibration).

In more detail, as shown in Figure 3, said outer ring 7.2 comprises:

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- an indicator of rotation 7.1, which comprises an element with a circumferential sector shape, and

- an outer wing 7.4 having a substantially circumferential crown shape, concentric with respect to the axis of said outer ring 7.2, limited by said indicator 7.1 by one or more connecting elements 7.41 (in the non-limiting example of the attached figures, said one or more connecting elements 7.41 comprise three teeth, even a single tooth being sufficient to achieve the objective of the present invention).

From the opposite side of said indicator 7.1, said outer wing 7.4 (of an angular width substantially equal to that of the arc of said indicator 7.1) is firmly fixed by means of a tongue 9 on the cover 2.2 of the thermostat 1; or said outer wing 7.4 is securely fixed directly to said cover 2.2.

The ligation between the outer wing 7.4 of the adjustment button 7 and the tongue 9 is carried out with known fixing means, such as laser welding or adhesive bonding (for example, cyanoacrylate or UV ultraviolet adhesive).

Therefore, what has just been described makes it possible to obtain secure locking means of the adjustment button 7 (consisting of the set "inner sleeve 7.3 - outer ring 7.2 with indicator 7.1 and outer wing 7.4"), with the thermostat 1 calibrated to the T.box temperature value with which it leaves the factory and based on it, the energy efficiency class is assigned to the water heater.

In addition, said blocking means allow to avoid accidental calibration errors not intended for thermostat 1, caused by shocks and vibrations during transport and of the various logistic operations to which the product is subjected in the different stages of the distribution chain.

However, an operator can easily disassemble said blocking means (understood as "operator" regardless of the distributor of the product or the installer or the end customer of the water heater to which the thermostat 1 is applied) in case it intends to change the value T.box calibration, renouncing the energy efficiency indicated on the label.

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In fact, the connecting elements 7.41 are designed in such a way that simply forcing in rotation the adjustment button 7 (which acts directly on its indicator 7.1 or by means of known indirect means associated with said indicator 7.1, such as an additional button of the water heater control interface) allows the operator to break them, eliminating the ligation between the indicator 7.1 and the outer wing 7.4, again ensuring that said adjustment button 7 can rotate to calibrate the thermostat 1 at a temperature value other than T .box

Laboratory tests have determined that the ligation represented by said connecting elements 7.41 can be conceived in such a way that it is broken by applying a torsion force of approximately 0.3 Nm, that is, a force that can be easily exerted manually but which still avoid a break due to involuntary causes.

In this way, the user can modify the T.box calibration value of the thermostat 1, adjusting it to a higher temperature (for example T.perf) to obtain the best performance with respect to the available hot water or adjusting it to a lower temperature for further increase energy efficiency.

Obviously, the adjustment button 7 still has a travel stop which prevents it from exceeding the calibration point corresponding to the maximum safety temperature T.max, a value that cannot be exceeded for safety reasons.

From the above description, the advantages that can be achieved with the present invention are revealed, the first one referring to the possibility of the manufacturer blocking the thermostat 1 calibration to the T.box calibration value to obtain the class of energy efficiency required by EU legislation and allow, at a later time, that the operator remove at discretion said locking means to change the calibration of thermostat 1 according to their needs.

A second category of advantages refers to the possibility of achieving a more precise calibration of the thermostat 1 compared to the commonly used prior art systems, which are represented in the example of Figure 1: in the latter, in fact, the connection between knurled nut and adjustment button 7 ', made in a single

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piece, necessarily causes a slight angular deviation and the bad calibration resulting from the calibration value established by said ring nut.

Said angular deviation is substantially equal to a fraction of an angle of rotation that depends on the number of teeth presented by the ring nut: by way of example, the knurling of an annular nut of a thermostat such as that shown in Figure 1 presents 32 teeth, therefore, the angular deviation caused by the connection with the adjustment button 7 'can reach approximately 360 ° / 32/2.

This type of inconvenience is overcome, or at least reduced, thanks to the coaxial connection between the outer ring 7.2 and the inner sleeve 7.3 described in the present invention: in fact, the calibration of the thermostat 1 is assigned only to said inner sleeve 7.3 (previously coupled to knurled nut 8), without any risk that the application of said outer ring 7.2 (previously fixed to cover 2.2 of thermostat 1) subsequently modifies the established calibration.

It is evident that, for those skilled in the art, various variants of the blocking means described above are possible without departing from the novel scope of the inventive idea, and it is also evident that in the implementation of the present invention the various elements described previously they can be replaced by other technically equivalent ones.

For example, in the variant of the attached figures it has been observed that the connecting elements 7.41 between the outer wing 7.4 and the indicator 7.1 of the outer ring 7.2 comprise three teeth intended to be broken by the action of a rotating force.

However, said connecting elements 7.41 can be replaced by suitable equivalent means (also in amounts other than those shown in the figure), such as one or more welding or adhesion points or adhesive elements, always intended to break as a result. of an external force that eliminates the bond between said outer wing 7.4 and the assembly "inner sleeve 7.3 - outer ring 7.2 with indicator 7.1".

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It is not necessary to think about how to conceive these elements of union. See, for example, the ties that can be broken in the plastic caps of the bottles.

Similarly, with the appropriate structural changes of the elements of the adjusting button 7, said connecting elements 7.41 can be placed in any intermediate position between the inner sleeve 7.3 and the cover 2.2, since the fundamental condition for the calibration of thermostat 1 reaches the T.box value is that said inner sleeve 7.3 can no longer move once the initial calibration phase has been completed.

An additional construction variant may comprise the realization of an adjustment button 7 consisting of a single piece comprising the inner sleeve 7.3 and the outer ring 7.2 already joined together: although in this way a precise calibration such as the which allows the main variant with the two separate elements, there is always the advantage of the locking means, which the operator can later extract at his discretion.

Another variant may also comprise an adjustment button 7 with the two elements "inner sleeve 7.3 - outer ring 7.2" initially separated, so that they are held together once the calibration of thermostat 1 to the T.box value has been completed by said inner sleeve 7.3, but with said outer ring 7.2 which is fixed to the cover 2.2 only at the end of said initial calibration stage.

It should also be emphasized that the configuration and position of the indicator 7.1 of the outer wing 7.4 and the related joining means 7.41 shown in the figure constitute only a non-limiting example of a preferred variant of the present invention: in fact, they may adopt different shapes and positions, comprising the feature of allowing the locking, then removable, of the inner sleeve 7.3.

Finally, it is possible to provide a variant in which, after the removal of the blocking means when breaking the connecting elements 7.41, there are some means to assist the operator in any case in the recovery activity of the thermostat 1 calibration to the initial value T.box, for example by means of identification elements on the adjustment button 7 or on the button of the additional control interface of the water heater or thanks to another type of

signals, such as a click that can be perceived when the temperature value T.box is reached.

By way of non-limiting example, Figure 5 represents a possible variant of the present invention in which said means are present to assist the operator in restoring the initial calibration setting corresponding to the operating value T.box, even after removal of the blocking means breaking one or more joining means 7.41. In this variant example, the indicator 7.1 of the outer ring 7.2 also has a concavity 7.10, suitable for cooperating with a corresponding convex part 10 7.40, made on the outer wing 7.4.

Thus, even after the breaking of the connection means 7.41 (with the consequent freedom of rotation provided to the adjustment button 7, still within the limits of the predetermined tolerances and the maximum safety temperature T.max), the operator 15 you can easily find the calibration point T.box preset initially, in case you intend to return to the best energy configuration: in fact, the concavities that correspond 7.10 and the convex part 7.40 act as a clear identification sign for the operator, as well as the shape of the connection that reproduces when the concavity 7.10 of the indicator 7.1 is found again in the convex part 7.40 of the outer wing 20 7.4.

Claims (11)

5 10 fifteen twenty 25 30 1. Thermostat (1) for the safety and adjustment of a heating appliance, in particular an electric storage water heater, which includes: - a containment box (2), which has a base (2.1) and a cover (2.2), - temperature regulating means (3) suitable for cutting and restoring the power supply of one or more heating elements, - means of calibration (7, 7.1, 8) of the operating temperatures (T.perf, T.max, T.box), comprising an adjustment button (7, 7.1) acting on an underlying knurled toothed nut (8), characterized because said adjustment button (7, 7.1) further comprises locking means with corresponding connecting elements (7.41) suitable for locking said adjustment button (7, 7.1) with said cover (2.2), to avoid changing the temperature of operation (T.box) initially calibrated, said connection elements (7.41) being subsequently subjected to a break, to remove said locking means of said adjustment button (7, 7.1) and allow the change of said initially calibrated operating temperature (T.box). 2. Thermostat (1) according to the preceding claim, characterized in that said adjustment button (7, 7.1) comprises: - an inner sleeve (7.3) acting on said underlying knurled ring nut (8) for the calibration of said operating temperatures (T.perf, T.max, T.box), - an outer ring (7.2) with a corresponding rotation indicator (7.1), said outer ring (7.2) being arranged coaxially with respect to said inner bushing (7.3) and thereby fixedly limited thereto once the calibration is completed of said initial operating temperature (T.box), - an outer wing (7.4) linked, on the one hand, to said rotation indicator (7.1) by means of said connecting elements (7.41) and, on the other hand, to a tongue (9) disposed on said 5 10 fifteen twenty 25 30 cover (2.2) of said thermostat (1), linking with said tongue (9) before calibration of said initial operating temperature (T.box), said outer wing (7.4) being limited to said tongue (9) once said connecting elements (7.41) have been subjected to breakage. 3. Thermostat (1) according to any of the preceding claims, characterized in that said connecting elements (7.41) are subjected to breakage by the application by an operator of a rotational force on said adjustment button (7, 7.1), acting directly or indirectly on said rotation indicator (7.1). 4. Thermostat (1) according to the preceding claim, characterized in that said connecting elements (7.41) comprise one or more teeth, said rotational force is equal to approximately 0.3 Nm. 5. Thermostat (1) according to claim 2, characterized in that said rotation indicator (7.1) of said outer ring (7.2) is in the form of a circumferential sector, said outer wing (7.4) is in the form of a concentric circumferential crown with respect to the axis of said outer ring (7.2) and an angular width substantially equal to that of the arc of said circumferential sector of said rotation indicator (7.1). 6. Thermostat (1) according to any of the preceding claims, characterized in that said initially calibrated and non-changeable operating temperature (T.box) in the presence of said blocking means is the temperature value such that it reaches at least the minimum energy efficiency class according to EU ErP legislation, said operating temperature (T.box) is that with which said thermostat (1) leaves the factory, lower than the operating temperatures (T.perf, T.max) attainable by said thermostat (1) after removal of said blocking means. 5 10 fifteen twenty 25 30 7. Thermostat (1) according to any of the preceding claims, characterized in that said adjustment button (7, 7.1) comprises a final travel stop suitable for preventing the calibration point corresponding to the maximum safety temperature (T.max) from being exceeded. 8. Thermostat (1) according to any of the preceding claims, characterized in that It comprises identification elements intended to allow the operator to recover the calibration point corresponding to the initially calibrated operating temperature (T.box), even after the removal of said blocking means. 9. Thermostat (1) according to the preceding claim, characterized in that said identifying elements comprise reciprocating coupling means, made respectively on the indicator (7.1) of the outer ring (7.2) and on the outer wing (7.4). 10. Thermostat (1) according to the preceding claim, characterized in that said reciprocating coupling means comprise a concavity (7.10) made in said indicator (7.1) of the outer ring (7.2), suitable for cooperating with a corresponding convex part (7.40), made on said outer wing (7.4). 11. Electric water heater, characterized in that it comprises the thermostat (1) according to any of claims 1 to 10.