Patent attributes
A circuit is used which includes: first and second channels having first and second input ports, respectively, and a third channel having an end where the first and second channel meet and are connected to the third channel. A first liquid to the first input port is supplied to generate a reference flow. A second liquid is supplied by the target pump to the second input port. An interface of the first and the second liquids joined in the third channel is inspected. The operation condition of the target pump is determined from a condition of the inspected interface. Pulsation in the flow supplied by the target pump is detected from waves in the interface visually inspected. The image of the interface may be magnified. Pulsation in the reference pump may be absorbed.
