Environmental matter detection system

• US 4,891,628 A
• Filed: 12/29/1988
• Issued: 01/02/1990
• Est. Priority Date: 12/29/1988
• Status: Expired due to Fees

• Current Assignee: Leonard Zuckerman
• Original Assignee: Leonard Zuckerman
• Inventors: Zuckerman, Leonard
• Primary Examiner(s): Orsino, Joseph A.
• Assistant Examiner(s): Scutch, III, Frank M.
• Application Number:
  US07/291,528
• Time in Patent Office: 369 Days
• Field of Search: 340/580, 340/601, 340/582, 73/170 R, 244/134 F, 244/134 D
• US Class Current: 340/582
• CPC Class Codes: G01V 1/001 Acoustic presence detection
• CPC Class Codes: G08B 19/02 Alarm responsive to formation or anticipated formation of ice

Abstract

A matter sensing apparatus includes a piezoelectric transducer, having a face susceptible to matter accretions at a surface for which matter accretion detection is desired. The electrical circuit of the transducer is coupled in the feedback path of an amplifier to establish an oscillator that oscillates at frequencies determined by the resonant frequency of the transducer and the loading on its face. The oscillator signals are converted to binary signals and utilized with binary signals, provided by a thermostat, that a representative of temperatures above or below a selected temperature to provide signals indicative of whether ice or other matter has accredited on the surface.

Claims

1. An apparatus for sensing matter accretions on a surface comprising:

an electro-mechanical transducer having a face directly exposed to matter accretions at said surface and a vibration frequency responsive to matter accretions on said face;

oscillator means coupled to said transducer for oscillating at a frequency controlled by said vibration frequency;

means coupled to said oscillator means for providing first signals representative of said oscillating frequencies;

thermostat means for providing second signals representative of temperatures of said surface; and

means responsive to said first and second signals for providing signals representative of matter conditions on said face.

2. The apparatus of claim 1 wherein said first signals means includes:

means responsive to signals generated by said oscillator means for providing rectangular waves at said frequencies;

converting means coupled to said rectangular waves means for providing signals representative of said frequencies; and

means responsive to said signals provided by said converting means for providing said first signals.

3. The apparatus of claim 2 wherein:

said first signals means includes comparator means wherefrom said first signals are provided at a first level when said signals from said converting means exceed a predetermined threshold and at a second level when said signals from said converting means do not exceed said predetermined threshold; and

said thermostat means provides said second signals at a first level when said temperatures exceed a preselected temperature threshold and at a second level when said temperatures do not exceed said preselected threshold.

4. The apparatus of claim 1 further including means for cyclically activating and deactivating said oscillator means.

5. The apparatus of claim 4 wherein said oscillator means is deactivated for intervals that are much longer than intervals during which said oscillating means are activated.

6. The apparatus of claim 1 wherein said electro-mechanical transducer is a piezoelectric transducer.

7. An apparatus for sensing matter accretions on a surface comprising:

an electro-mechanical transducer having a face directly exposed to matter accretions at said surface and a vibration frequency responsive to matter accretions on said face such that said vibration frequency decreases with loads on said face created by said matter accretions;

oscillator means coupled to said transducer for providing oscillations at a frequency controlled by said vibration frequency;

said transducer and oscillator means constructed and arranged such that said oscillations terminate when a predetermined load level is accumulated on said face;

means coupled to said oscillator means for detecting said oscillations and providing a first signal having a first level when said oscillations are detected and a second level when oscillations are not detected;

means for providing a second signal having a first level when temperatures at said surface exceed a preselected temperature and a second level when temperatures at said surface do not exceed said preselected temperature; and

means responsive to said first and second signals for providing signals representative of matter accretions on said surface or no matter accretions on said surface and type of said accretions on said surface.

8. The apparatus of claim 7 further including means for cyclically activating and deactivating said oscillator means.

9. The apparatus of claim 8 wherein said oscillating means is deactivated for intervals that are much longer than intervals during which said oscillator means are activated.

10. The apparatus of claim 7 wherein said forced vibration element is a piezoelectric transducer.