United States Patent an tm Patent Number: 4,733,095
Kurahashi et al.  Date of Patent: Mar. 22, 1988
 METHOD AND DEVICE FOR DETECTING AVERAGE LIQUTD LEVEL IN A BOTTLE
 Inventors: Michito Kurahashi, Osaka; Hisao
Tomikawa, Kagamigahara; Yuji Doi,
Takatsuki, all of Japan
 Assignee: Suntory Limited, Osaka, Japan
 Appl. No.: 933,987
 Filed: Nov. 24,1986
 Foreign Application Priority Data
Nov. 28, 1985 [JP] Japan 60-268178
 Int. Q.4 G01N 15/06
 U.S. a 250/577; 340/619;
 Field of Search 250/577, 575, 223 R;
 References Cited
U.S. PATENT DOCUMENTS
3,094,213 6/1983 Wyman .
3,452,208 6/1969 Giltinan .
4,246,489 1/1981 Yoshida et al 250/577
4,672,216 6/1987 Pitt et al 250/575
A method for detecting a liquid level is monitored at mutually opposing sides of a liquid containing bottle. For monitoring the liquid level at each side of the bottle, a diffused light beam is irradiated toward the liquid surface from a level below the liquid surface. The light reflected at the liquid surface and the light refracted at the liquid surface are detected by a photo-receiving camera which is focused at a standard liquid level. An average value of the monitored liquid levels at both sides is taken as a liquid level indicative value. By employing the aforemention method, accurate detection of the liquid level becomes possible even when the liquid level is unstable.
14 Claims, 7 Drawing Figures