WO2000006822A1

WO2000006822A1 - Process for the controlled power supply of machines for steam generation and appliances connected thereto

Info

Publication number: WO2000006822A1
Application number: PCT/EP1998/004741
Authority: WO
Inventors: Marcello Ferrante
Original assignee: Marcello Ferrante
Priority date: 1998-07-29
Filing date: 1998-07-29
Publication date: 2000-02-10

Abstract

The process for the controlled electric power supply of machines for steam generation provided with a boiler (11) with an internal heating resistor (12) and for the appliances having high current absorption connected thereto, such as electric irons (13), contemplates the steps of alternately supplying the electric power to the internal resistor (12) of the boiler (11) and to the appliance (13), with alternate periods of activation/deactivation which are out of phase with respect to one another in time and are substantially complementary.

Description

TITLE :

"Process for the controlled power supply of machines for steam generation and appliances connected thereto"

DESCRIPTION Object of the present invention is a process for the controlled power supply of machines for steam generation and appliances connected thereto.

The invention applies to machines for the generation of steam that may be associated to any type of appliance, such as electric irons, cleaning appliances, humidifiers, multi-purpose appliances, etc., for the purpose of controlling the supply to the corresponding appliance so as never to exceed the maximum power that can be supplied by the electric power mains. Steam generating machines are known that are equipped with a boiler presenting inside one or more electrical resistors having the function of transforming water into steam.

These machines may be associated, by means of suit- able connections, to a number of possible household appliances, such as electric irons or multi-purpose cleaning appliances.

One of the problems arising from the use of these steam-generating machines lies in the fact that the si- multaneous use of the boiler and appliance may result, in certain cases, in approaching or exceeding the maximum limit of power that the electricity mains are able to supply, in particular in the sphere of household applications . This occurs especially in the case of particular high current-absorption appliances, such as irons, or else in the simultaneous use of two or more appliances.

In this case, the absorption by the iron that is necessary for heating the ironing plate, or another ap- pliance connected to the machine, added to the current absorption of the boiler in operation, leads to a total absorption that is excessive for normal domestic use.

If this occurs, the electric current absorption overload leads to the interruption of the supply of cur- rent, with the consequent inconveniences caused by the interruption of the activity in progress, the need to reactivate the power supply, the cooling of the water with corresponding expenditure of energy to restore the evaporation temperature, and other inconveniences of the sort. Switching systems are known that stop supply to the appliance if the overall current absorption approaches the maximum limit of the mains supply, thereby in any case interrupting the activity in progress and creating consequent inconveniences. Instead, automatic systems that enable prevention of overstepping of the said limit of supply, which allow the user to proceed with the activity in progress without creating any consequence perceptible to the user, are not known to the applicant. To solve the above problem and to achieve further advantages, the applicant proposes the following solution.

The purpose of the invention is to create a process that enables supply, in a controlled way, of a stea - generating machine connected to an appliance that has a high current absorption, so as never to overstep the limit of power that can be supplied by the mains, at the same time keeping the operation of the said appliance substantially unaltered. According to the invention, supply to the steam- generating machine is managed by an electronic card which incorporates at least one modulation unit.

In the case where the steam-generating machine is connected to a high-absorption appliance, such as an iron, electric power is supplied in a discontinuous way, alternately to the resistor of the steam generating machine and to the appliance, in such a manner that the resistor of the steam generating machine is supplied in the interval of deactivation of the appliance, and vice versa.

Such a solution makes it possible to avoid absorption peaks, in so far as there is no simultaneous supply of both loads.

The high switching frequency of the supply between one load and the other renders the discontinuity of supply practically imperceptible. The thermal inertia of the ironing plate in the case of an iron and the resistor of the boiler make up for the substantially instantaneous deactivations of the supply. According to one embodiment of the invention, the switching to the one or the other load occurs as the wave is passing through zero with the purpose of avoiding disturbances both of power supply to the appliance and in the mains. The principle of controlled supply of the process according to the invention may be extended also to the case of two or more appliances connected simultaneously to the steam generating machine.

The invention will be better understood from the following description of a preferred embodiment made with reference to the figures of the attached drawing, in which:

- Figure 1 shows an example of a steam-generating machine connected for the supply to an electric iron; - Figure 2 shows a graph of a possible solution for the supply of the boiler-appliance assembly;

- Figure 3 presents the electrical diagram of the process according to the invention.

With reference to the figures, the steam generating machine 10 that adopts the process according to the invention is equipped with an internal boiler 11 associated to a spiral-shaped electrical resistor 12 that has the function of heating the water 14 present inside the boiler 11 and of transforming it into steam. By means of appropriate connections, various appliances suitable for achieving the desired functions may be connected to the said machine 10.

In the case illustrated, the machine 10 is connected to an iron 13 as an exemplification of a high current- absorption appliance.

The connection of the iron 13 to the machine 10 determines a high level of absorption resulting from the need of bringing the ironing plate 15 to a temperature of approximately 170-180°C. This absorption of the iron 13, added to the absorp- tion of the resistor 12 of the boiler 11, may reach an excessively high level, in particular in the presence of absorption peaks, for normal applications in the domestic sphere, where the electrical power mains normally sup- plies power not exceeding a value of approximately 3 kW.

For this purpose, the card of the microprocessor inside the machine 10 is programmed to modulate, at a high frequency, electric power supply to the assembly formed by the resistor 12 and the iron 13, by supplying the said power alternately to the resistor 12 and to the iron 13, the corresponding activation/deactivation intervals being out of phase with respect to one another in time and substantially complementary.

This modulation is obtained, according to the exem- plifying diagram of Fig. 3, by switching at high frequency, using suitable switching means 16, the supply voltage between the resistor 12 of the boiler 11 and the iron 13.

As may be seen from the voltage vs. time graph of Fig. 2, this switching determines a period Tl of supply of the resistor, and a period T2 of supply of the iron 13, the said period T2 coinciding with the period of de- activation of the resistor 12.

In this way, there never occurs the absorption peak deriving from the sum of the supplies, so that there is no risk of overstepping the maximum limit of power supply of the domestic power mains.

In the illustrated solution, the duration of the period Tl coincides with that of period T2. According to a modification, depending upon the spe- cific requirements, the durations of the periods Tl and T2 are different.

The switching between one and the other load, i.e. in the present case the resistor 12 and the iron 13, takes place at the point where the wave passes through zero, so that this switching will not cause disturbances of supply.

Given the high frequency of switching, the thermal inertia of the resistor 12 and of the ironing plate 15 renders the temporary absence of supply imperceptible and does not create any inconvenience in use, such as temperature drops or jumps.

Claims

1. Process for the controlled electric power supply of machines for steam generation and appliances connected thereto, in particular high current absorption appli- ances, such as electric irons (13), the said steam generating machines comprising at least one boiler (11) provided with an internal resistor (12) , characterized in that it provides for the alternate supply of the internal resistor (12) of the boiler (11) and of at least one ap- pliance (13), with alternate periods of activa- tion/deactivation which are out of phase with respect to one another in time and are substantially complementary.

2. Process according to Claim 1, characterized in that it provides for periods (Tl) of electric power sup- ply of the resistor (12) of the boiler (11) which are alternated with periods (T2) of supply of the appliance (13), there being envisaged, between two periods (Tl) of supply of the resistor (12), a deactivation period having a duration substantially equal to the period (T2) of sup- ply to the appliance (13) .

3. Process according to Claim 1 or Claim 2, characterized in that the period (Tl) of supply of the resistor (12) has a duration which is equal to that of the period (T2) of supply of the appliance (13).

4. Process according to Claim 1 or Claim 2, characterized in that the period (Tl) of supply of the resistor (12) has a duration which is different from that of the period (T2) of supply of the appliance (13).