(under subclass 200) Devices wherein the indication is given by a chemical reaction, e.g., change in color, smoke, odor, etc., and means to hold the chemicals.
SEE OR SEARCH THIS CLASS, SUBCLASS:
214, for smoke or odor as an indicator where no chemical reaction holding means is used.
SEE OR SEARCH CLASS
252, Compositions,
408, for compositions designed for indicating.
277, Seal for a Joint or Juncture, for a generic sealing means or process, 321, for a seal combined with a wear, proper seating or presence indicator, sampler, or inspection feature.
285, Pipe Joints or Couplings,
13, and 45 for signaling means with structure of the class type.
422, Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,
50+, for determining qualitatively or quantitatively the presence of chemical compound.
423, Chemistry of Inorganic Compounds,
264, for changing color characteristic of impurity.
436, Chemistry: Analytical and Immunological Testing,
1, 183 for determining qualitatively or quantitatively the presence of chemical compound.
