PRESSURE SENSOR FOR AN ELECTRIC HOUSEHOLD APPLIANCE AND ASSOCIATED METHOD

• US 20100307236A1
• Filed: 02/06/2009
• Published: 12/09/2010
• Est. Priority Date: 02/08/2008
• Status: Active Grant

• Current Assignee: ITW Appliance Components doo (Illinois Tool Works Inc.)
• Original Assignee: ITW Metalflex d.o.o. (Illinois Tool Works Inc.)
• Inventors: Giordano, Sergio
• Granted Patent: US 8,689,626 B2
• Time in Patent Office: Days
• US Class Current: 73/299
• CPC Class Codes: G01D 18/008 with calibration coefficients stored in memory
• CPC Class Codes: G01D 3/022 having an ideal characteristic, map or correction data stored in a digital memory
• CPC Class Codes: G01F 23/18 Indicating, recording or alarm devices actuated electrically
• CPC Class Codes: G01L 27/002 Calibrating, i.e. establishing true relation between transducer output value and value to be measured, zeroing, linearising or span error determination

Abstract

A pressure sensor including a body, device for receiving pressure associable with a tube connected to a fluid-filled tank of an electric household appliance, wherein the level of the fluid is to be measured. It further includes a device for emitting electric frequency signal proportional to the pressure received; a device carried aboard the body, on which a plurality of response frequency values emitted by the emitting means associated with corresponding pressure values at the pressure receiving means, were recorded. The pressure sensor is used with a pressure reading system carried by the device for receiving pressure. The pressure reading system includes two devices for reading values recorded on the pressure sensor, i.e. pressure and frequency values; and electric frequency signals. The pressure reading system further includes a processing device for interpolating the pressure value associated with every signal on the basis of the values read by the reading device.

Claims

1. A pressure sensor comprising a body, pressure receiving means associable with a tube of an electric household appliance, e.g. connected to a tank in which there is collected in use a fluid, the level of which is intended to be measured, and means emitting an electric frequency signal proportional to the pressure received by the receiving means;

characterized in that it further comprises readable storing means carried aboard the body, integrally therewith, on which there were recorded a plurality of response frequency values emitted by the emitting means associated with corresponding pressure values which were present each time at the pressure receiving means.

2. A sensor according to claim 1, characterized in that said readable storing means comprise at least one label externally fixed onto the body and bearing either engraved or printed, on an exposed face thereof, a one- or two-dimensional barcode, reproducing said pressure values and said frequency response values associated therewith.

3. A sensor according to claim 2, characterized in that said readable storing means comprise two labels externally fixed onto the body and both bearing either engraved or printed, on an exposed face thereof, a barcode reproducing said pressure values and said frequency response values associated therewith;

a first of said labels bearing said barcode in the one-dimensional form and a second label, fixed to a different part of said body and far from the one carrying the first label, bearing said barcode in the two-dimensional form.

4. A sensor according to claim 3, characterized in that said body is essentially cylinder-shaped, said second label being carried by a flat upper end face of the body and said first label being carried by a cylindrical side surface of the body.

5. A sensor according to claim 1, characterized in that said readable storing means comprise at least one memory chip, e.g. a FLASH memory, fixed aboard the body, either externally or internally to the same;

and interface means, again carried aboard said body, for connecting said memory chip to an electronic control unit outside the body and independent thereof.

6. A sensor according to claim 1, characterized in that it is an analogue sensor.

7. A pressure reading system, specifically for detecting the level of a fluid in a tank of an electric household appliance, comprising a pressure sensor according to any one of the preceding claims, first reading means of the pressure and frequency values recorded on the readable storing means, second reading means of the electric frequency signal present at the emitting means, and processing means for interpolating the pressure value associated with the signal read each time by the second reading means on the basis of the values read by the first reading means.

8. A system according to claim 7, characterized in that said first and second reading means and said processing means are permanently associated with said electric household appliance, while said pressure sensor is removably associated with said electric household appliance and is connected in use to said tank by means of a tube associated with said pressure receiving means.

9. A method for performing accurate pressure readings, specifically for detecting the level of a fluid in a tank of an electric household appliance, by means of an analogue pressure sensor, comprising the steps of:

applying a plurality of known pressure values to the sensor and measuring a frequency response value of the sensor for each applied pressure value;

recording all the applied pressure values and, for each of them, the corresponding measured frequency response value on readable storing means;

fixing the readable storing means aboard the sensor, specifically onto a body of the same;

in use, applying the pressure to be measured to the sensor, detecting the frequency response values generated by the sensor, reading the pressure and frequency response values previously recorded on the readable storing means, and

for each detected frequency response value, calculating the corresponding pressure value by interpolating it on the basis of the previously recorded pressure values and corresponding frequency response values of the sensor.