WO2019129707A1

WO2019129707A1 - A steam iron and a method for automatic temperature and steam setting by measuring conductivity of fabrics

Info

Publication number: WO2019129707A1
Application number: PCT/EP2018/086577
Authority: WO
Inventors: Burcu UNAT; Asli Saime Kayihan; Yalcin Guldali; Ismet Arsan; Hanife Eda ARSLAN; Mehmet Marasli
Original assignee: Arcelik Anonim Sirketi
Priority date: 2017-12-26
Filing date: 2018-12-21
Publication date: 2019-07-04
Also published as: TR201721933A2

Abstract

The present invention relates to a steam iron (1) for determining the type of a fabric (K) to be ironed and setting to predetermined temperature and steam values according to the type of the fabric (K), comprising in its most basic form, a main body (2), a spray mechanism (3), a liquid dripping system (4) to drip liquid on fabrics (K), a conductivity measurement apparatus (5) having a first conductive probe (51) and a second conductive probe (52), enabling measuring conductivity value of a fabric (K) between said probes by contacting said conductive probes to said fabric (K), and a control unit (6) adapted to determine the type of a fabric (K) to be ironed according to the conductivity values received from the conductivity measurement apparatus (5), and to set to predetermined temperature and steam values according to fabric (K) types.

Description

A STEAM IRON AND A METHOD FOR AUTOMATIC TEMPERATURE AND STEAM SETTING BY MEASURING CONDUCTIVITY OF FABRICS

Technical Field

The present invention relates to a steam iron and a method developed to determine the type of a fabric to be ironed by measuring electrical conductivity of said fabric, and to enable temperature and steam of the iron to be set in accordance with the determined fabric type.

Prior Art

Most of the commercially available irons are designed to have three levels associated with ironing temperatures of textile products or to have gauges on which product types such as cotton, denim, wool, linen are listed depending on the type of fibers. In such products, a user sets the temperature himself/herself, and the temperatures can be increased or decreased in steps by the user.

The two most significant parameters effecting ironing performance in steam irons are base plate temperature and steam flow rate. The fabric fibers loosen as temperature increases, the temporary hydrogen bonds between the fabric fibers are easily broken with steam, and reorientation of the fibers is enabled by mechanical motion. The weak hydrogen bonds are broken upon subjecting a wrinkled fabric to heat and steam, and they are rearranged in an orderly manner by the effect of ironing. Different fabric types loosen in differing temperatures and therefore the ideal ironing temperatures thereof differ.

As can be seen in Table 1 below, the ironing temperature required to iron cotton fabric is approximately 230°C, and the ironing temperature for delicate fabrics such as silk, wool is about 140°C. The obligation of setting iron base plate temperatures in a wide range such as between 140°C and 230°C, leads to perform the ironing process in three different temperature settings according to fabric types.

Table 1: Loosening thresholds of different textile fabrics and applicable ironing temperatures.

Table 1

Fibers	Loosening threshold (°C)	Ironing temperature (°C)
Cotton	-	230
Linen	-	220
Ramie	-	220
Silk	-	140
Wool	-	160
Polyester	232-240	150
Polyamide	220-235	150

In current steam irons, a user performs the ironing process by setting the temperature according to fabric types. An incorrect temperature setting due to a user having incorrect information about the type or combination of fabrics, causes the fabric to burn and/or flash at high temperatures, or ineffective ironing process due to using lower temperatures instead of higher temperatures required by the ironing process. This makes the ironing process more difficult.

Another effective parameter in removing wrinkles is steam flow rate. Steam flow rate is the most influential parameter on ironing performance, and is more effective in ironing fabrics with cotton and wool content compared to synthetic fabrics.

Giving high amounts of steam independent of the fabric type does not damage fabrics but giving less steam when high amounts of steam is required such as when ironing cotton, adversely affects the ironing performance. In addition, giving more steam to synthetic products requiring less amounts of steam leads to early depletion of water in a water chamber and the need for continuous refilling of water.

The European patent document no. EP0612996 mentions an iron enabling detecting a fabric's type and automatically setting temperature accordingly. Said iron comprises an infrared light source to illuminate a fabric, a detector having photoconductive cells and determining the wavelength of the light reflecting from the fabric, and a processor connected to the detector. By using said iron, fabric type is detected by analyzing radiations reflecting from different fabrics in different wavelengths, and temperature is set automatically according to the detected fabric type.

The European patent document no. EP0523793 (B1) mentions an iron enabling distinguishing delicate and non-delicate fabrics by measuring in appropriate relative humidity conditions the electrostatic load variation arising from friction during ironing. The average amplitude of an electric signal is measured from the electrostatic load variation occurring due to the base of the iron sliding on fabric when the iron is moving. In order to be able to measure electrostatic load, the fabric should have a humidity value lower than a certain humidity value, therefore the humidity content of the fabric is controlled by means of a humidity sensor.

Problems Solved by the Invention

The aim of the present invention is to realize a steam iron and a method capable of determining textile types, iron temperatures and steam settings independent of users, enabling ironing in appropriate temperature and steam conditions according to conductivity values of fabrics by measuring the resistance variation on a fabric on which water is dripped, depending on different water absorption capacities of textiles and diffusion velocity of water between the fibers of said textiles.

In order to determine a textile type in the ironing process, the invention utilizes the phenomenon of different damped textile products having different electrical conductivity values. Conductivity values remain identical for dry textile products regardless of type, but is characteristic for each fabric type for varying humidity values (the dampness level of a fabric). A predetermined amount of water is dripped on a fabric before or during ironing in order to evaluate different textile products in an identical humidity or dampness level and to distinguish varying fabric types. Varying electrical conductivity values are obtained by a measurement system from different textile products dripped with identical amount of water thereon, depending on their types.

The invention benefits from differing conductivity characteristics of damp fabrics, measures average conductivity values in a given duration of fabrics impregnated with water and determines the type of a fabric by utilizing variations in conductivity values. Temperature and steam is automatically set accordingly, independent of users. Textile products are thus ironed in correct heat and steam settings, preventing fabrics from being subjected to damages such as burning or flashing and providing ease of use to the consumers.

The advantages of the steam iron disclosed in the present invention may be summed up as follows:

Types of different fabrics can be detected according to the differing conductivity values of said fabrics by means of the system adapted to the textile type iron.
Appropriate temperature and steam values are determined according to detected value.
Textile damages such as burning or flashing are prevented by determining ironing conditions suitable for a fabric type independent of users.
Products requiring high temperatures and/or steam amounts are prevented from being ironed in lower temperatures and steam amounts, thereby avoiding low ironing performance.
Excessive water consumption is prevented by optimizing steam levels for textile types such as synthetic fabrics not requiring high amounts of steam.
Ease of use is provided for the users by means of a convenient system.

In its most basic form, the steam iron of the invention comprises a main body, a spray mechanism, a liquid dripping system to drip liquid on fabrics, a conductivity measurement apparatus having a first conductive probe and a second conductive probe, enabling measuring conductivity value of a fabric between said probes upon the conductive probes being contacted to said fabric, and a control unit adapted to determine the type of a fabric to be ironed according to the conductivity values from the conductivity measurement apparatus, and to set to predetermined temperature and steam values according to determined fabric types.

Said conductivity measurement apparatus comprises a first resistor connected to an end of the first conductivity probe; a second resistor connected between the first resistor and the ground; and a transimpedance amplifier circuit having an operational amplifier whose inverting inlet is connected to the second conductive probe and whose noninverting inlet is connected between the first resistor and the second resistor, and a feedback resistor disposed on the feedback line of the operational amplifier.

The liquid dripping system comprises a duct connected to a spray mechanism and a nozzle provided at an and of said duct to drip liquid on fabrics. Said nozzle is disposed on the first conductivity probe or the second conductivity probe.

In order to determine the type of a fabric to be ironed and to set to predetermined temperature and steam values according to fabric type by using the above-mentioned steam iron, first, the liquid dripping system drips a liquid on the fabric surface, the conductivity value between the first conductive probe and the second conductive probe contacted to the fabric surface for a given time is measured by the conductivity measurement apparatus and the obtained value is transmitted to the control unit, the control unit calculates the average of said conductivity values, and queries whether said average measurement value is within a first range between a first conductivity value and a second conductivity value. If said average measurement value is within the first range, then a predetermined temperature and steam value for a first textile material is set. If said average measurement value is not within the first range, then the control unit queries whether said average measurement value is within a second range between said second conductivity value and a third conductivity value. If said average measurement value is within the second range, then a predetermined temperature and steam value for a second textile material is set. If said average measurement value is not within the second range, then a predetermined temperature and steam value for a third textile material is set.

The first range is 60 to 90% of the maximum conductivity value of a dry fabric, the first textile material corresponding to this first range is determined as having cotton content, and the control unit sets the steam iron to high temperature and steam values.

The second range is 10 to 60% of the maximum conductivity value of a dry fabric, the second textile material corresponding to this second range is determined as having synthetic content, and the control unit sets the steam iron to low temperature and steam values.

The third textile material having 10% of the maximum conductivity value of a dry fabric is determined as having wool content, and the control unit sets the steam iron to low temperature and high steam values.

Detailed Description of the Invention

A steam iron and a method realized to achieve the aims of the present invention is illustrated in the accompanying drawings, wherein:
Figure 1: is a view of the steam iron from below.
Figure 2: is a view of the A-A section of Figure 1.
Figure 3: is a circuit diagram of the conductivity measurement apparatus.
Figure 4: is a frontal view of the conductivity measurement apparatus.
Figure 5: is a flow diagram of the method of the invention.
Figure 6: is a graph of average electrical conductivity values for cotton, synthetic and wool fabrics.

The elements in the figures are numbered individually and the correspondence of these numbers are given hereinafter.

Steam iron
Main body
Spray mechanism
Liquid dripping system

41. Duct

42. Nozzle
5. Conductivity measurement apparatus
51. First conductive probe
52. Second conductive probe
53. First resistor
54. Second resistor
55. Transimpedance amplifier circuit
56. Operational amplifier
57. Feedback line
58. Feedback resistance
59. Variable resistance
6. Control unit

K. Fabric

Vc. Supply voltage

Vo. Outlet voltage

T. Ground

Figures 1 and 2 show a steam iron (1) used in a preferred embodiment of the invention. Said steam iron (1) preferably has three step (high, medium and low) temperature and steam settings, and comprises a main body (2), a spray mechanism (3), a liquid dripping system (4) connected to said spray mechanism (3), a conductivity measurement apparatus (5) having a first conductive probe (51) and a second conductive probe (52), enabling measuring the conductivity value between said probes, and a control unit (6) adapted to determine the type of a fabric (K) to be ironed according to the conductivity values received from the conductivity measurement apparatus (5), and to set to predetermined temperature and steam values according to fabric (K) types.

The conductivity measurement apparatus (5) is provided on the main body (2) preferably on the rear portion of the main body (2). When the first conductive probe (51) and the second conductive probe (52) are contacted to the surface of the fabric (K) to be ironed, the conductivity measurement apparatus (5) measures the conductivity between said probes, and the control unit (6) determines the type of the fabric (K) by processing said measurement values.

Figure 3 shows the circuit diagram of the conductivity measurement apparatus (5) comprising a first conductive probe (51), a second conductive probe (52), a first resistor (53) connected to an end of the first conductivity probe (51); a second resistor (54) connected between the first resistor (53) and the ground (T); and a transimpedance amplifier (TIA) circuit (55) having an operational amplifier (56) whose inverting inlet is connected to the second conductive probe (52) and whose noninverting inlet is connected between the first resistor (53) and the second resistor (54), and a feedback resistor (58) disposed on the feedback line (57) of the operational amplifier (56). The supply inlet of the operational amplifier (56) and an end of the first conductive probe (51) are connected to a power point supplying a supply voltage (Vc) to the first conductive probe (51) and to the operational amplifier (56).

The variable resistance (59) displayed between the first conductive probe (51) and the second conductive probe (52) in Figure 3, represents the resistance value of the fabric (K). Said resistance value does not vary when textiles are dry but varies upon the fabric (K) being damped with a given amount of water. This is because of the fiber structures and sizes of gaps in between the fibers differing according to type of the textile. Different textile types have different resistance values due to water diffusing in varying velocities in a given duration between textile fibers of varying fiber structures. In the invention, electrical conductivity values according to resistance values of the fabric (K) surface are measured by means of the conductivity measurement apparatus (5), and the control unit (6) determines the type of the fabric (K) according to said measurements.

In order to determine the type of the fabric (K) to be ironed, the first conductive probe (51) and the second conductive probe (52) provided on the conductivity measurement apparatus (5), are contacted to the fabric (K) surface and a low DC voltage is generated between said probes, thereby creating a current flow in micro ampere levels towards the transimpedance amplifier circuit (55) via the fabric (K) arranged between the first conductive probe (51) and the second conductive probe (52). This current value is converted to voltage by means of the transimpedance amplifier circuit (55), generating an outlet voltage (Vo) which is subsequently read by the control unit (6). In an embodiment of the invention, the control unit (6) is a micro-processor comprising an analog/digital (A/D) port, and said outlet voltage (Vo) is read via said analog/digital port. A value proportional to the conductivity of the fabric (K) is thus obtained. When the fabric (K) is dry, the value read would be the maximum conductivity value (M). As explained hereinafter, fabric (K) types are distinguished by expressing the average conductivity values read from different fabrics (K), in a percentage of said maximum conductivity value (M).

Figure 4 shows the conductivity measurement apparatus (5) comprising a liquid dripping system (4). A liquid dripping system (4) is placed in the conductivity measurement apparatus (5) as an electrical conductivity value is characteristic for a textile in conditions in which the textile is damp. Said liquid dripping system (4) utilizes the already available spray mechanism (3) of the steam iron (1).

The liquid dripping system (4) comprises a duct (41) and a nozzle (42). The water sent through the present spray of the iron (1) by means of mechanical force, passes through the duct (41) extending towards one of the first conductive probe (51) or the second conductive probe (52) provided on the conductivity measurement apparatus (5), and damps the fabric (K) through the nozzle (42) disposed at the end of the duct (41). The water in a constant amount sent from the liquid dripping system (4) is dripped on the fabric (K) surface before or during ironing. Resistance values are measured according to absorption speed of water on the fabric (K) surface between the first conductive probe (51) and the second conductive probe (52). After dripping water, data is received via the first conductive probe (51) and the second conductive probe (52) throughout a given duration (e.g. two minutes). Absorption of water by the fabric (K) is waited for during this duration. It is critical that the liquid, preferably water dripped by the liquid dripping system (4) to reach the contact area of the first conductive probe (51) and the second conductive probe (52). Therefore, the liquid dripping system (4) is positioned appropriately in the conductivity measurement apparatus (5), preferably at a region of the first conductive probe (51) or the second conductive probe (52) proximate to the main body (2).

Figure 5 shows the flow diagram of the method of the invention. The method enabling determining fabric (K) types and automatically setting temperature and steam according to fabric (K) type by using the above-disclosed steam iron (1) is explained hereinafter.

In the method of the invention, in order to determine the type of a fabric (K), first, the steam iron (1) is switched to an automatic mode via a user interface (for example, a button or keypad) provided thereon. Then, the first conductive probe (51) and the second conductive probe (52) are contacted the fabric (K) and the liquid dripping system (4) drips a constant amount of water on the fabric (K) surface. After dripping said water, the conductivity measurement apparatus (5) measures the conductivity value between the probes contacted to the fabric (K) surface throughout a given duration (for example two minutes), and transmits the measured values to the control unit (6).

The control unit (6) calculates the average of said conductivity measurement values, and queries whether said average measurement value is within a first range between a first conductivity value and a second conductivity value. If said average measurement value is within the first range, then the fabric (K) to be ironed is determined to be made of a first textile material, and a predetermined temperature and steam value for this first textile material is set by the control unit (6). In an embodiment of the invention, said first range is between 60 to 90% of the maximum conductivity value (M) of the dry fabric (K), and the first textile material corresponding to this range has cotton content. The control unit (6) sets the steam iron (1) to high temperature and steam values to iron the fabric (K) with cotton content.

If said average measurement value is not within the first range, then the control unit queries whether said average measurement value is within a second range between said second conductivity value and a third conductivity value. If said average measurement value is within the second range, then the fabric (K) to be ironed is determined to be made of a second textile material, and a predetermined temperature and steam value for this second textile material is set by the control unit (6). In an embodiment of the invention, said second range is between 10 to 60% of the maximum conductivity value (M) of the dry fabric (K), and the second textile material corresponding to this range has synthetic content. The control unit (6) sets the steam iron (1) to low temperature and steam values to iron the fabric (K) with synthetic content.

If said average measurement value is not within the second range, this implies that said average measurement value is less than the third conductivity value, therefore the fabric (K) to be ironed is determined to be made of a third textile material, and a predetermined temperature and steam value for this third textile material is set by the control unit (6). In an embodiment of the invention, said third conductivity value is 10% of the maximum conductivity value (M) of the dry fabric (K), and the third textile material having a lower conductivity than this value has wool content. The control unit (6) sets the steam iron (1) to low temperature and high steam values to iron the fabric (K) with wool content.

Figure 6 displays the average electrical conductivity values measured on different textile types (cotton, synthetic, wool) by the conductivity measurement apparatus (5). As can be seen in said figure, the average electrical conductivity values measured throughout two minutes differ depending on the type of textile. The average conductivity value obtained in the measurements being in the range of 60 to 90% of the maximum conductivity value (M) of the dry fabric (K) reveals that the fabric (K) has cotton content, the value being in the range of 10 to 60% of the maximum conductivity value (M) of the dry fabric (K) reveals that the fabric (K) has synthetic content, and the value being less than 10% of the maximum conductivity value (M) of the dry fabric (K) reveals that the fabric (K) has wool content. As disclosed above, the type of a fabric (K) is determined on the basis of said data obtained from repetitive measurements, and the appropriate temperature and steam amount is determined according to the type of the fabric (K).

Claims

A steam iron (1) for determining the type of a fabric (K) to be ironed and setting to predetermined temperature and steam values according to the type of the fabric (K), comprising in its most basic form a main body (2) and a spray mechanism (3), characterized by

- a liquid dripping system (4) to drip liquid on the fabric (K),

- a conductivity measurement apparatus (5) having a first conductive probe (51) and a second conductive probe (52), enabling measuring the conductivity value of the fabric (K) between said probes by contacting said probes to a fabric, and by

- a control unit (6) adapted to determine the type of the fabric (K) to be ironed according to the conductivity values received from the conductivity measurement apparatus (5), and to set to predetermined temperature and steam values according to the determined fabric (K) type.
The steam iron (1) according to claim 1, characterized by a conductivity measurement apparatus (5) comprising a first resistor (53) connected to an end of the first conductivity probe (51); a second resistor (54) connected between the first resistor (53) and the ground (T); and a transimpedance amplifier circuit (55) having an operational amplifier (56) whose inverting inlet is connected to the second conductive probe (52) and whose noninverting inlet is connected between the first resistor (53) and the second resistor (54), and a feedback resistor (58) disposed on the feedback line (57) of the operational amplifier (56).
The steam iron (1) according to claim 1, characterized by the liquid dripping system (4) comprising a duct (41) connected to the spray mechanism (3), and a nozzle (42) provided at an end of the duct (41) to drip liquid on a fabric (K).
The steam iron (1) according to claim 3, characterized by the nozzle (42) provided on the first conductivity probe (51) or the second conductivity probe (52).
A method for determining the type of a fabric (K) to be ironed and setting to predetermined temperature and steam values according to the fabric (K) type by using a steam iron (1) according to any one of the preceding claims, characterized by the steps of

- the liquid dripping system (4) dripping a liquid on the fabric (K) surface;

- the conductivity measurement apparatus (5) measuring throughout a given duration the conductivity values between the first conductive probe (51) and the second conductive probe (52) contacted to the fabric (K) surface, and transmitting the measured values to the control unit (6);

- the control unit (6) calculating the average of said measured conductivity values;

- the control unit (6) querying whether said average measurement value is within a first range between a first conductivity value and a second conductivity value;

- if said average measurement value is within the first range, then setting to a predetermined temperature and steam value for a first textile material;

- if said average measurement value is not within the first range, then querying whether said average measurement value is within a second range between said second conductivity value and a third conductivity value; and

- if said average measurement value is within the second range, then setting to a predetermined temperature and steam value for a second textile material
A method according to claim 5, characterized by the step of setting to a predetermined temperature and steam value for a third textile material if said average measurement value is not within the second range.
A method according to claim 5 or 6, characterized in that the control unit (6) determining to have cotton content, a fabric (K) of a first textile material corresponding to the first range which is 60 to 90% of the maximum conductivity value of the fabric (K) in a dry state, and setting the steam iron (1) to high temperature and steam values.
A method according to any one of the claims 5 to 7, characterized in that the control unit (6) determining to have synthetic content, a fabric (K) of a second textile material corresponding to the second range which is 10 to 60% of the maximum conductivity value of the fabric (K) in a dry state, and setting the steam iron (1) to low temperature and steam values.
A method according to any one of the claims 5 to 8, characterized in that the control unit (6) determining to have wool content, a fabric (K) of a third textile material with a conductivity value less than the third conductivity value which is 10% of the maximum conductivity value of the fabric (K) in a dry state, and setting the steam iron (1) to low temperature and high steam values.