Patent ID: 8757864

Claim:
A chemical analyzer comprising: means for supplying a sample into a reaction container provided with an opening; means for supplying a reagent into the reaction container; a mixing tool having a plate with a substantially flat bottom surface to mix a fluid to be measured that contains a sample and a reagent, a sample and a reagent being supplied into the reaction container; means for measuring a property of a fluid in the reaction container; and a control unit for controlling driving of the mixing means, a vertical drive mechanism to move the mixing tool up and down, wherein the control unit controls the vertical drive mechanism and is programmed to immerse the mixing tool into a fluid in the reaction container at an immersion speed and to move the mixing tool up and down in a fluid in the reaction container so as to cause upward and downward flows of a fluid which is disposed below the mixing tool, and wherein the control unit controls the vertical drive mechanism and is programmed to position the substantially flat bottom surface of the mixing tool in a vicinity of a bottom of the reaction container to mix a fluid, and to move the mixing tool up and down in the vicinity of the bottom of the reaction container with a first frequency in which the mixing tool moves at least twice the immersion speed and with a first vibration amplitude that is about 20% of a height of a fluid in the reaction container to intensively move a portion of a sample that is at the bottom of the reaction container by local flows of a fluid at the bottom of the reaction container, and wherein the control unit controls the vertical drive mechanism and is programmed to raise the substantially flat bottom surface of the mixing tool to a vicinity of a center of a fluid in the reaction container and to move the mixing tool up and down around the vicinity of the center of a fluid with a second frequency in which the mixing tool moves at 50 to 200% of the immersion speed and with a second vibration amplitude that is about 80% of a height of a fluid in the reaction container to globally and uniformly mix a portion of a sample which was previously locally mixed by the local flows at the bottom of the reaction container.