LIQUID LEVEL DETECTOR

• Main Authors: YASUDA ATSUSHI, YASUKI YUSUKE, IWADE JUN
• Format: Patent
• Language: English; Japanese
• Published: 07.05.2015
• Subjects: MEASURING; MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUIDLEVEL; METERING BY VOLUME; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To prevent false detection of a liquid level.SOLUTION: A liquid level detector includes: a first float 23 having a first specific gravity SG1 smaller than true specific gravity SGt of oil 3 alone, and configured to vary vertical first moving position P1 according to a relation between an apparent specific gravity SG1 of the oil 3 containing air bubbles or the true specific gravity SGt and the first specific gravity SG1; a second float 33 having a second specific gravity SG2 smaller than the true specific gravity SGt and the first specific gravity SG1, and configured to vary a vertical second moving position P2 according to a relation between the apparent specific gravity SGa or the true specific gravity SGt and the second specific gravity SG2; and a control circuit 50 which selects a corresponding moving position of the moving positions P1, P2 in detecting a liquid level L. The control circuit 50 detects a liquid level L, on the basis of the second moving position P2 in disregard of the first moving position P1, when the first moving position P1 is equal to a first lower limit position P1l and the second moving position P2 exceeds a second lower limit position P2l(S107). 【課題】液面レベルの誤検出を抑制すること。【解決手段】オイル３単独の真比重ＳＧｔよりも小さな第一比重ＳＧ１を有し、気泡の混入したオイル３の見かけ比重ＳＧａ又は真比重ＳＧｔと第一比重ＳＧ１との大小関係に応じて、上下の第一移動位置Ｐ１が可変となる第一フロート２３と、真比重ＳＧｔ及び第一比重ＳＧ１よりも小さな第二比重ＳＧ２を有し、見かけ比重ＳＧａ又は真比重ＳＧｔと第二比重ＳＧ２との大小関係に応じて、上下の第二移動位置Ｐ２が可変となる第二フロート３３と、移動位置Ｐ１，Ｐ２のうち液面レベルＬの検出において依拠する移動位置を選択する制御回路５０と、を設ける。制御回路５０は、第一移動位置Ｐ１が第一下限位置Ｐ１ｌとなり且つ第二移動位置Ｐ２が第二下限位置Ｐ２ｌよりも上方となると、第一移動位置Ｐ１を無視して第二移動位置Ｐ２に基づき液面レベルＬを検出する（Ｓ１０７）。【選択図】図８