Title:
【発明の名称】液面検知装置
Document Type and Number:
Japanese Patent JP3064487
Kind Code:
B2
Abstract:
PURPOSE:To provide a level detecting device capable of detecting the contact of a probe top onto the level of a detected liquid at the time of lowering the probe toward the level of the detected liquid. CONSTITUTION:A metallic plate 5 is earthed near a vessel 4 in which a detecting liquid 4a is received, and the electrostatic capacity value between the metallic plate 5 and a level detecting needle 3 is differed depending on whether the level detecting needle 3 is in contact with a detected level 4b or not. A differential circuit 13 differentiates the signal oscillated by an oscillating circuit 6 according the electrostatic capacity value, wherein the sensitivity to the input frequency is set in such a manner as to be increased by the oscillated signal from the oscillator circuit 6 at the time when the level detecting needle 3 is in non-contact with the detected level. Thus, when the level detecting needle 3 makes contact with the detected level 4b, the sensitivity of the differential circuit 13 is reduced, and its output is also changed. This output change is detected by a voltage detector 14, whereby the level 4b can be detected.
Inventors:
Hiroyuki Kogusu
Yu Okudokoro
Yu Okudokoro
Application Number:
JP13429491A
Publication Date:
July 12, 2000
Filing Date:
June 05, 1991
Export Citation:
Assignee:
Olympus Optical Co., Ltd.
International Classes:
G01F23/26; (IPC1-7): G01F23/26
Attorney, Agent or Firm:
Takehiko Suzue