FIELD OF THE INVENTION

The invention is related to a coffee machine, specifically a coffee machine capable of detecting leakage current.

PRIOR ART

The use of coffee machines has started to increase. These machines mentioned cooks/brews the coffee in the coffee pot by heating a load element with energy supplied from a power source.

The mentioned coffee machines generally consist of a coffee pot and a base. Electrical connection is provided by fitting the female input on the base onto the male indentation on the bottom of the coffee pot. It is important that the mentioned structure is separable from each other and can be easily cleaned, but this situation poses a risk of leakage current. When the mentioned coffee pot and base are washed, the points where the electrical connections are located can remain wet, which can cause leakage current during coffee preparation. In some applications, the coffee pot can also be connected by a connector on the side, but this does not have much effect on the situation regarding leakage current.

Under normal circumstances, when a leakage current occurs in the coffee machine as stated, the residual current device/systems on the grid come into play and cut off the electricity in the entire area connected to the RCD by tripping it. This causes all electrical appliances in the relevant area to shut down and remain closed until user intervention.

There are household appliances equipped with internal current leakage detection systems to prevent the main safety switch (RCD) from tripping. One example of this is the blender structure described in US20210018572A1 publication. The leakage detection system presented here is designed on the electrical transmission connector structure where live wire (phase) transmission can occur. A pseudo ground surface is created around the connector in this structure and the detection of events such as liquid spills on the connector is planned. However, in reality, leakage current can occur not only through the connector but also from various other points. The most typical example of this is wet cables or moisture-absorbing resistors. Therefore, the ground fault circuit interrupter system should be more comprehensive.

The CN207662453U publication describes a leakage current detection system for coffee machines. The system is used for testing purposes before the coffee machines are released to the market and is not a system that operates while being used by end-users.

Regarding leakage current detection, although residual current detection relays are available for external use, these structures have two disadvantages.

These types of structures, since they detect leakage current by measuring the imbalance between phase and neutral, typically in a coffee machine when the operating current is 10 amps, need to be able to detect a ground fault imbalance of 5 milliamps, this requiring a sensitivity better than 0.05% in ratio. Achieving this level of sensitivity requires serious calibration and cost. On the other hand, maintaining the sustainability of such high calibration sensitivities over time presents difficulties.

However, a bigger problem is that residual current protection relays only come into operation after a residual current has been detected, and this can cause other protection relays in series with it on the network to trip simultaneously. This is because electrical leaks can cause a sudden surge in current and trigger other circuit breaker relays until the mechanical circuit breaker relay comes into operation. This requires the residual current detection system to operate not directly on the grid but on a limited test current.

There is a need for coffee machines with a pre- leakage current detection system in the market, and the provided detection system is expected to have minimal impact on the total cost, be reliable, not affected by the phase/neutrality direction depending on the direction of the plug insertion, and have high measurement tolerance.

As a result, all abovementioned problems have made it necessary to make an improvement in the relevant technical field. OBJECTIVE OF THE INVENTION

The present invention aims to eliminate the abovementioned problems and to make a development in the relevant technical field.

The main objective of the invention is to create a coffee machine structure that is capable of detecting leakage current that have a cooking compartment that can be removed and installed for cleaning purposes, and as a result, prevents the general residual current relays from tripping, especially in the area where it is used.

Another objective of the invention is to create a coffee machine structure with a low-cost current detection element.

Another objective of the invention is to present a coffee machine structure that prevents the user from being injured due to electrical current.

BRIEF DESCRIPTION OF THE INVENTION

The invention is related to a coffee machine so as to fulfil all aims mentioned above and will be obtained from the following detailed description. Accordingly, the coffee machine includes a coffee pot and a heating element for brewing the coffee in the coffee pot a base on which the said pot is to be placed and a plug connected to the said base a primary and a secondary heating connection element provided on the coffee pot and the base respectively, to transmit the energy provided by the plug to the heating element and a leakage current detection element provided between the heating connection elements and the plug that preventing the operation of the heating element when a leakage current is detected.

As a result, when a leakage current occurs in a coffee machine, the residual current relay of the area where the coffee machine is used will not trip, and as a result, all electricity in the area will not be cut off.

Another embodiment of the invention, said leakage current detection element comprises a selection relay to transmit the power coming from the said plug directly to heating element or the leakage current detection element before the heating element

Another embodiment of the invention, said leakage current detection element, contains a regulating resistor connected to the plug and an optocoupler connected in series with said regulating resistor, which generates a signal when current is passed through it; and a processing unit that controls the selection relay with the signal received from said optocoupler.

As a result, leakage current detection can be achieved with a very low-cost structure. In addition, the current value has been reduced by using a regulating resistor, preventing possible injuries caused by current.

Another embodiment of the invention, includes an input relay between the plug and a leakage current detection element for connecting the leakage current detection element to the phase terminal or neutral terminal of the plug

As a result, regardless of which direction the plug is inserted into the socket, the leakage detection can be provided from both the phase and neutral sides.

Another embodiment of the invention, characterized by the feature that the processing unit is configured to control the input relay.

BRIEF DESCRIPTION OF DRAWINGS

A schematic view of the coffee machine according to the invention is given in Figure 1 .

The circuit diagram of a structure of the leakage current element is given in Figure 1 .A.

Figure 1.B shows the circuit diagram of another implementation of the leakage current circuit.

The drawings do not necessarily need to be scaled and some details that are not necessary to understand the present invention may have been omitted. In addition, elements that are at least largely identical or at least largely have identical functions are indicated with the same number.

DESCRIPTION OF THE REFERENCES IN FIGURES

1. Coffee machine

2. Coffee pot 3. Base

4. Primary heating connection means

5. Secondary heating connection means

6. Heating element

7. Plug

10. Leakage current detection element

11. Input relay

12. Leakage current detection circuit

121. Regulating resistor

122. Optocoupler

123. LED

124. Photodiode

13. Selection relay

14. Switch

F. Phase

N. Neutral

G. Input

O. Output

R. Load element

M. Processing unit

DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the invention a coffee machine (1 ) is described by means of examples only for clarifying the subject matter such that no limiting effect is created.

The invention relates to a coffee machine (1) and it is comprising: a coffee pot (2) and a heating element (6) for brewing the coffee in the coffee pot (2); a base (3) on which the said coffee pot (2) is to be placed and a plug (7) connected to the said base (3); a primary and a secondary heating connection element (4, 5) provided on the coffee pot (2) and the base (3), respectively, to transmit the energy provided by the plug (7) to the heating element (6); a leakage current detection element (10) provided between the heating connection elements and the plug (7), capable of detecting the leakage current before applying power to the heating element and preventing the operation of the heating element (6) when a leakage current is detected.

Referring to Figure 1 ; the coffee machine (1 ) mentioned includes a coffee pot (2) where coffee and water are poured. Said coffee pot (2) contains a heating element (4), preferably a resistor, for brewing the coffee.

The mentioned coffee pot (2) is placed on a base (3). The coffee machine comprises a male primary heating connection means (4) and a female secondary heating connection means (5) on the coffee pot (2) and base (3). Preferably, the male primary heating connection means (4) is provided on the surface of the base (3), and the female secondary heating connection means (5) is provided on the bottom of the coffee pot (2). The opposite configuration is also possible, but it is disadvantageous since the coffee pot (2) needs to stand on the ground alone.

The mentioned base (3) contains a plug (7). The mentioned plug (7) provides power to the coffee machine (1 ) by being connected to an electrical outlet. The mentioned plug (7) is electrically associated with the primary and secondary heating connection elements (4, 5) and performs the cooking/brewing process by supplying power to the heating element (6).

A leakage current detection element (10) is arranged between the plug (7) and the heating connection elements on the mentioned base (3). Essentially, the leakage current detection element (10) prevents the heating element (6) from operating and the general safety switch (residual current relay) from tripping if there is a leakage in the coffee machine (1 ).

According to Figure 1A; the phase (F) terminal and neutral (N) terminal of the mentioned plug (7) are connected to an input relay (11 ). The mentioned input relay (11 ) in one of its positions connects the phase (F) and in the other position connects the neutral (N) to a ground fault circuit interrupter. Since it is not directly possible to determine which way the plug (7) is connected to the outlet, each end must be checked separately. Such an input relay (11 ) may not be necessary in fixed plug like US plug and socket systems.

The input relay (11 ) is connected to a leakage current detection circuit (12). The leakage current detection circuit (12) is associated with a processing unit (M). The leakage current detection circuit (12) sends a signal to the processing unit (M) indicating whether a ground fault is present or not.

The mentioned selection relay (13) is connected to the output of the leakage current detection circuit (12). In one position, the selection relay (13) connects the primary heating connection means (4) that represented as the load element (R) to the leakage current detection circuit (12) or alternatively, through the secondary heating connection element (5), to the heating element (6); in the other position, the selection relay (13) separates the leakage current circuit (12) from the system, enabling the power coming from the plug (7) to be directly transmitted to the heating element (6) through the primary heating connection means (4), or alternatively, through the secondary heating connection means (5). Therefore, in both positions, current reaches the heating connection elements and the heating element (6).

A switch (14) is also connected to the output (0) of the load element (R). The switch (14) is used to cut the circuit on and off. Preferably, the switch (14) is selected as a TRIAC.

According to Figure 1.B, as previously described, the leakage current detection circuit (12) is connected to the phase (F) or neutral (N) terminal by the input relay (11 ). Its function is the same when connected to either terminal. There is a regulating resistor (121 ) at the input of the leakage current detection circuit (12). The regulating resistor (121 ) reduces the current value of the power coming from the plug (7) to make it safe for the user. For example, when a 200k ohm regulating resistor (121 ) is used with a 200- volt input voltage, the current is 1 mA, which is not dangerous for human body. Here, the regulating resistor (121 ) value is preferably selected to be less than 5mA to prevent harm to the user. In addition, the regulating resistor (121 ) value is selected to be lower than the general safety switch (residual current device) tripping current value. Generally, residual current devices cuts off value is 30mA. Therefore, the regulating resistor (121 ) must be selected to ensure that the current in the circuit is less than 30mA.

An optocoupler (122) is connected in series with the mentioned regulator resistor (121 ).

When detecting a leakage current, the switch (14) is open, meaning the circuit is cut off and no current will flow if there is no leakage on the circuit. If there is leakage current on the circuit, even if the switch (14) has cut off the circuit, the current will flow from the leakage point to the ground.

If there is a leakage current, current flows through the optocoupler (122). When current flows through the optocoupler (122), the LED (123) inside the optocoupler (122) lights up and the light created by the LED (123) is converted to a signal by the photodiode (124) inside the optocoupler (122), and this signal is sent to a processing unit (M) connected to the optocoupler (122). When the signal arrives, the processing unit (M) leaves the selection relay (13) in a position that connects the load element (R) to the leakage current detection circuit (12). If there is no current flow through the optocoupler (122), the processing unit (M) will disconnect the load element (R) from the leakage current detection circuit (12) and connect the load element (R) to the input (G), so the power coming directly from the plug (7), and close the switch (14) to complete the circuit. Therefore, the coffee machine (1 ) will operate normally. This process is applied to both the phase (F) and neutral (N) terminals by changing the position of the input relay (11 ). Any leakage current on the system can be detected in this way.

Here, preferably the processing unit (M) can also control the input relay (11 ).

The mentioned leakage current detection is performed once or twice before the coffee machine (1 ) starts working, depending on whether both the phase (F) and neutral (N) terminals are checked.

A reverse-biased diode can be used to protect the LED (123) inside the optocoupler (122) from reverse currents when used with alternating current.

The protection scope of the invention is defined in the attached claims and is not limited to the embodiments described in this detailed description. It is clear that a person skilled in the art can develop similar embodiments within the scope of the above-mentioned descriptions without deviating from the main theme of the invention.