Patent number: 6190611
Abstract: A harness indicator is highly reactive to a trace amount of Ca2+, and is slow to degrade in a high temperature environment of greater than 50° C. In one embodiment, the hardness indicator contains EBT, a pH buffer, and a masking agent as main components, and an admixture of Mg-EDTA. In another embodiment, the hardness indicator contains EBT, a pH buffer, and a masking agent as main components, and an admixture of anhydrous Mg-EDTA. In another embodiment, the hardness indicator contains EBT, a pH buffer, and a masking agent as main components, and an admixture of anhydrous Mg-EDTA and potassium sorbate. In a further embodiment, the hardness indicator contains EBT, a pH buffer, and a masking agent as main components, and an admixture of Mg-EDTA and potassium sorbate. In a further embodiment, the hardness indicator contains EBT, a pH buffer, and a masking agent as main components, and an admixture of potassium sorbate.
Type:
Grant
Filed:
August 27, 1998
Date of Patent:
February 20, 2001
Assignees:
Miura Co., LTD.,, Miura Institute of Research & Development Co.,
Ltd.
Inventors:
Kazuhiro Tachino, Yoshitami Tsubota, Sadatoshi Takechi, Junichi Nakajima, Masazumi Yamashita, Katsufumi Isshiki, Takeshi Fukumura, Yuuji Ukena
