Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
  • D06F75/00—Hand irons
  • D06F75/08—Hand irons internally heated by electricity
  • D06F75/26—Temperature control or indicating arrangements
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
  • D06F75/00—Hand irons
  • D06F75/08—Hand irons internally heated by electricity
  • D06F75/10—Hand irons internally heated by electricity with means for supplying steam to the article being ironed
  • D06F75/14—Hand irons internally heated by electricity with means for supplying steam to the article being ironed the steam being produced from water in a reservoir carried by the iron
  • D06F75/18—Hand irons internally heated by electricity with means for supplying steam to the article being ironed the steam being produced from water in a reservoir carried by the iron the water being fed slowly, e.g. drop by drop, from the reservoir to a steam generator

Definitions

• the invention relates to a steam iron comprising: a soleplate; a steam generator operative to convert water into steam, the steam generator comprising a steam chamber which is thermally coupled to the soleplate; means for sensing an actual temperature of the soleplate and means for setting a desired temperature of the soleplate.
• a steam iron is known from United States Patent No. 4,939,342.
• During ironing the user of a steam iron selects a soleplate temperature depending on the properties of the fabric to be ironed. When the user selects a lower temperature, it takes a considerable time until the soleplate is cooled down to the lower desired temperature, particularly when the iron cools down freely on a tray or in heel rest position.
• a further problem with steam irons is the risk of scorching when the iron is left unattended on the fabric.
• Object of the invention is to provide a steam iron with reduced cool-down time when a lower soleplate temperature has been selected. It is a further object of the invention to provide a steam iron with reduced risk of scorching when the steam iron is left unattended on a fabric.
• the steam iron as specified in the opening paragraph is characterized in that the steam iron further comprises a control means for comparing the actual temperature and the desired temperature of the soleplate and for generating an activation signal for activating the steam generator if the actual temperature is higher than the desired temperature.
• the steaming action of the steam generator cools down the soleplate, because the evaporation of water withdraws heat from the soleplate.
• the cool-down time to a lower soleplate temperature is thereby reduced considerably.
• the means for setting the desired soleplate temperature may comprise a dial or buttons for manually selecting the temperature.
• the steaming action can further be used when the ironing work is finished. In that case the switch-off of the steam iron is considered as a very low desired soleplate temperature.
• the cooling of the iron after use increases the safety.
• the means for setting may comprise a means for providing a preset soleplate temperature which is indicative of scorching of the fabric to be ironed. In this case the cooling of the soleplate by evaporating water is used to prevent scorching if the iron is left on the fabric.
• a soleplate with low heat inertia is advantageous as it cools down in shorter time so that the risk of scorching is reduced still further.
• a preferred embodiment is characterized in that the steam generator further comprises a water tank for containing water to be converted into steam and a water pump f pumping water from the water tank to the steam chamber, the water pump being operative i response to the activation signal.
• a water pump enables an accurate dosing of th water to be evaporated depending on the needs during cool-down, anti-scorching, normal steaming and shot of steam.
• the steam iron according to die invention may be further provided with a hand sensor to detect whether the iron is in use or not, a position sensor to detect horizontal and vertical position of the iron and a motion sensor to detect whether the iron is being moved o not.
• the hand sensor, the position sensor and the motion sensor enable to detect a situation in which it may be concluded that the steam iron is left unattended on a fabric and that cooling of the soleplate is needed to prevent scorching.
• the motion sensor can be a conventional mercury pool switch, ball switch or can be based on measurement of the lower power need of the soleplate when the iron is left on the fabric. A much safer way is to provide the iron with a stand for receiving the iron in a rest position and means for detectin the reception of the iron in the stand.
• the means for detecting the reception of the iron in the stand can be for example a switch in the steam iron, which switch is engaged by a notch protruding from the stand which corresponds with a recess in the steam iron.
• Figure 1 shows schematically a cross section of a first embodiment of a steam iron according to the invention
• Figure 2 shows a flow chart of a control program for the first embodiment
• Figure 3 shows schematically a cross section of a second embodiment of a steam iron according to the invention.
• Figure 4 shows a flow chart of a control program for the second embodiment.
• Fig. 1 shows a first embodiment of a steam iron according to the invention.
• the steam iron has a conventional soleplate 2 which is heated by an electrical heating element 4.
• the actual temperature of the soleplate 2 is sensed by means of a temperature sensor 6, for instance a PTC-resistor, a NTC-resistor or a thermo-couple element.
• the desired temperature of the soleplate 2 is set by the user by means of a temperature selector or dial 8, but any other known setting means such as push buttons, touch buttons or knobs are possible as well.
• a controller 10 compares the actual temperature with the desired temperature and controls the heater 4, for example with a triac, to make the actual temperature equal to the desired temperature.
• the steam iron is further provided with a steam generator 12 comprising a water tank 14, a water pump 16 and a steam chamber 18 which is heated by the soleplate 2.
• the water pump 16 pumps water from the water tank 14 to the steam cham ⁇ ber 18 via a hose 20.
• the water evaporates in the steam chamber 18 and escapes via steam vents 22 in the soleplate 2.
• the water pump 16 is activated under command of an activation signal AS from the controller 10 when the user selects with dial 8 a desired temperature which is lower than the actual temperature of the soleplate 2 sensed by temperature sensor 6.
• the evaporation of water in the steam chamber 18 cools down the steam chamber 18 and so the soleplate 2.
• the cool-down time can be reduced considerably compared with the time for cooling when the steam iron is resting on its heel or on a tray.
• a heat capacity of 480 Joule/°C of the soleplate 2 it follows that the water consumption for steaming and so for cooling is about 0.2 gram water per degree Centigrade of the soleplate temperature. With 20 grams steam per minute the temperature drops about 100 degrees Centigrade in one minute. This corresponds to a cooling power of about 860 Watt. On a tray the dissipation of the iron is between 50 and 100 Watt.
• the cooling time can be shortened by a factor 10 or more by steaming.
• the controller 10 is preferably a microprocessor with suitable interface circuits to the dial 8, the temperature sensor 6, the heating element 4 and the water pump 16.
• Fig. 2 shows a flow chart for heating and cooling of the soleplate 2. The inscriptions to Fig. 2 are listed in Table I below: Table I
• the actual temperature of the soleplate T ⁇ p ⁇ is compared (block 202) with the desired temperature T desired set by the user using the dial 8. If the actual temperature of the soleplate is higher than the desired temperature, then the controller 10 activates the water pump 16 (block 204) by sending an appropriate activating signal AS to the water pump 16 and the soleplate is cooled down. After cooling down or if the desired temperature is not lower than the actual temperature, the controller 10 continues to control the heater 4 of the soleplate to maintain the desired soleplate temperature.
• the steam generator can, of course, also be used for normal steaming or for producing a shot of steam.
• the controller 10 sends appropriate activation signals of suitable duration to the water pump 16 depending on the actual or programmed steaming need.
• Fig. 3 shows a second embodiment of a steam iron according to the invention.
• the cooling effect of evaporating water is used not only for obtaining a fast cool-down of the soleplate after the setting to a lower desired temperature, but also for reducing the risk of scorching of the fabric to be ironed.
• a thin low heat inertia soleplate 2 which is, for example, heated by a thick film heating element 4.
• the low heat inertia reduces the risk of scorching considerably because of the fast decay of the soleplate temperature to lower temperatures.
• the steam iron of Fig. 3 works as explained in relation to the embodiment of Fig. 1 and the accompanying flow chart of Fig. 2.
• a hand sensor 24 in the handgrip 26 of the steam iron is provided further with a hand sensor 24 in the handgrip 26 of the steam iron.
• the hand sensor 24 can be of any conventional type, for example a capacitive sensor, a mechanical sensor, a resistive sensor or an optical sensor.
• the hand sensor 24 signals to the controller 10 whether the steam iron is being used (in-use) or not (not in-use) by the user.
• a position sensor 28 which signals to the controller 10 whether the steam iron is in a substantially horizontal position or in a substantially vertical position.
• the steam iron is in the substantially horizontal position when it is being moved over the fabric to be ironed or when it is resting on a tray or on the ironing board.
• the steam iron is in the substantially vertical position when it is resting on its heel.
• a motion sensor 30 which signals to the controller 10 whether the steam iron is being moved by the user or not.
• the position sensor 28 and the motion sensor 30 can each be of conventional design, for example a mercury pool switch mounted inside the steam iron in an appropriate position.
• a very safe way of motion detection is the provision of a stand 32 for placing the steam iron when it is not in use and means for detecting whether the steam iron is placed on the stand or not.
• the means can be a switch 34 engaged by a notch 36 on the stand 32. The switch 34 signals to the controller 10 whether the steam iron is certainly moving or not and provides a very safe indication of non-movement.
• Fig. 4 shows a flow chart for combined fast cooling and scorch prevention.
• the inscriptions to Fig. 4 are listed in Table II below:
• Block 402 If the handgrip 26 is touched by the user (block 402), then the signals from the position sensor 28 and from the motion sensor 30 or the stand detection switch 32 is ignored and the steam iron operates as already explained in relation to the flow chart of Fig. 2.
• Blocks 406, 408 and 410 of Fig. 4 correspond to blocks 202, 204 and 206, respectively, of Fig. 2. If desired, the steps of blocks 406 and 408 may be omitted from the flow chart of Fig. 4. If t handgrip is not touched by the user (block 402), then the controller 10 tests whether the iro is in a substantially horizontal position (block 404).
• the iron is in the substantially vertical heel rest position and the control of the heating of the soleplate can proceed as shown and explained in the flow chart of Fig. 2. This means that, if the user selects a lower temperature in the vertical heel rest position, the soleplate is cooled down by evaporating water. If the iron is in the substantially horizontally position (block 404), then the controller 10 tests whether the iron is on stand or not (block 412). If the iron is on stand the control returns to normal temperature control (block 406), otherwise the scorching prevention is enabled.
• the temperature of the soleplate is compared with a soleplate temperature T ⁇ o ⁇ g which is indicative of scorching of the fabric being ironed (block 414) If the actual temperature T ⁇ p ⁇ of the soleplate is greater than the scorching temperature ⁇ scorch i ng » tnen tne controller 10 activates the water pump (block 416) to cool down the soleplate 2 and any fabric underneath the soleplate.
• the scorching prevention by activating the steam generator takes place if the handgrip of the iron is not touched and the iron is in the horizontal position and is not placed on the stand.

Priority Applications (1)

Applications Claiming Priority (4)

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• 1996
  • 1996-01-10 BR BR9603891A patent/BR9603891A/pt not_active Application Discontinuation
  • 1996-01-10 KR KR1019960705204A patent/KR970701812A/ko not_active Application Discontinuation
  • 1996-01-10 EP EP96900018A patent/EP0752023A1/de not_active Withdrawn
  • 1996-01-10 JP JP8522748A patent/JPH09510905A/ja active Pending
  • 1996-01-10 CN CN96190153A patent/CN1148419A/zh active Pending
  • 1996-01-10 WO PCT/IB1996/000020 patent/WO1996023099A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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