Device for detecting the presence of frost and/or for measuring the thickness of frost by ultrasound and frost probe usable in such a device
First Claim
1. A device for detecting the presence of frost by ultrasound, comprising:
- a probe including an ultrasonic transducer of the piezoelectric type adapted to generate an ultrasonic acoustic emission wave and to detect ultrasonic acoustic echo waves reflected by the frost;
an actuating means for said probe arranged to provide to said ultrasonic transducer electrical energizing signals in order to cause said ultrasonic transducer to generate ultrasonic waves and then to detect and process the electrical echo signals at an output of said ultrasonic transducer; and
wherein said probe comprises, in addition, in combination;
(a) a frost detector placed in front of said ultrasonic transducer and constituted of a Bakelite cotton material having an acoustic impedance substantially different from that of the frost and comprised between 36×
105 and 44×
105 kg/m2 s, said frost detector having a front surface designed to be exposed to the surrounding atmosphere and hence subject to being covered with frost;
(b) an acoustic delay means adapted to ensure acoustic coupling and adaptation between said ultrasonic transducer and said frost detector and to separate in time the ultrasonic emission wave and the ultrasonic reflected wave, said acoustic delay means comprising an acoustic delay element which is inserted between said frost detector and said ultrasonic transducer which has an acoustic impedance comprised between 12×
106 and 36×
106 kg/m2 s, and which is made of a resin filled with a tungsten powder having a specific gravity of about 1.5-2; and
(c) A body of heat insulating material covering an assembly of said detector, said transducer, and said acoustic delay means.
1 Assignment
0 Petitions
Accused Products
Abstract
In a detection device of the presence of frost and/or measuring the thickness of the frost by ultrasound, a probe with a piezoelectric ultrasonic transducer generates an ultra-sonic acoustic emission wave and detects ultrasonic acoustic echo waves reflected by the frost. An actuating device for the probe is arranged to provide to the transducer electrical energizing signals. The probe comprises: a frost detector placed in front of the transducer and constituted of a material having an acoustic impedance between 30×105 and 44×105 kg m-2 s-1. This detector has a surface designed to be exposed to the surrounding atmosphere to be covered with frost. An acoustic delay device is adapted to ensure acoustic coupling and adaptation between the transducer and the detector and to separate in time the ultrasonic emission add reflected waves. A body of heat insulating material covers the assembly of the detector, the transducer and the acoustic delay device.
-
Citations
16 Claims
-
1. A device for detecting the presence of frost by ultrasound, comprising:
-
a probe including an ultrasonic transducer of the piezoelectric type adapted to generate an ultrasonic acoustic emission wave and to detect ultrasonic acoustic echo waves reflected by the frost; an actuating means for said probe arranged to provide to said ultrasonic transducer electrical energizing signals in order to cause said ultrasonic transducer to generate ultrasonic waves and then to detect and process the electrical echo signals at an output of said ultrasonic transducer; and wherein said probe comprises, in addition, in combination; (a) a frost detector placed in front of said ultrasonic transducer and constituted of a Bakelite cotton material having an acoustic impedance substantially different from that of the frost and comprised between 36×
105 and 44×
105 kg/m2 s, said frost detector having a front surface designed to be exposed to the surrounding atmosphere and hence subject to being covered with frost;(b) an acoustic delay means adapted to ensure acoustic coupling and adaptation between said ultrasonic transducer and said frost detector and to separate in time the ultrasonic emission wave and the ultrasonic reflected wave, said acoustic delay means comprising an acoustic delay element which is inserted between said frost detector and said ultrasonic transducer which has an acoustic impedance comprised between 12×
106 and 36×
106 kg/m2 s, and which is made of a resin filled with a tungsten powder having a specific gravity of about 1.5-2; and(c) A body of heat insulating material covering an assembly of said detector, said transducer, and said acoustic delay means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A device for measuring the thickness of frost by ultrasound comprising:
-
a probe including an ultrasonic transducer of the piezoelectric type adapted to generate an ultrasonic acoustic emission wave and to detect ultrasonic acoustic echo waves reflected by the frost; an actuating means for said probe arranged to provide to said ultrasonic transducer electrical energizing signals in order to cause said ultrasonic transducer to generate ultrasonic waves and then to detect and process the electrical echo signals at an output of said ultrasonic transducer; and wherein the probe comprises, in addition, in combination; (a) a frost detector placed in front of said ultrasonic transducer and constituted of a methyl polymethacrylate material having an acoustic impedance as close as possible to that of the frost and comprised between 30×
105 and 34×
105 kg/m2 s, said frost detector having a front surface designed to be exposed to the surrounding atmosphere and hence subject to being covered with frost, said material constituting said detector having a thickness providing acoustic delay so as to ensure acoustic coupling and adaptation between said ultrasonic transducer and said frost detector and to separate in time the ultrasonic emission wave and the ultrasonic reflected wave; and(b) a body of heat insulating material covering an assembly of said detector and said transducer. - View Dependent Claims (11, 12, 13, 14, 15, 16)
-
Specification