Abstract: A particle counter is configured to count particles contained in a sample fluid flowing through a flow passage by using light with which the flow passage is irradiated. The particle counter includes: a multi-flow cell having a plurality of the flow passages; a path adjuster configured to adjust a position of an optical path of the light with respect to the multi-flow cell, based on which flow passage is selected from the flow passages; and a light adjuster configured to adjust a condition of the light with which the selected flow passage is irradiated.

Abstract: A particle counter includes: a multi-flow cell with flow passages arrayed in a first direction and having a section including a detection region, for detecting a particle, formed when the flow passage is irradiated with irradiation light; a light receiving optical system configured to receive emitted light generated from a particle contained in sample fluid flowing in the at least one flow passage and passing through the detection region; an optical axis moving unit configured to move an optical axis of the irradiation light and an optical axis of the emitted light in the first direction; and a counter configured to count the particle for each particle size based on an intensity of the emitted light.

Abstract: An in-fluid floating substance measurement flow cell includes: a main body having at least a predetermined portion made of a material having translucency; and a flow passage formed inside the main body, having both end openings at an outer surface of the main body in a substantially identical direction, and configured such that fluid flows in the flow passage. The flow passage has a predetermined section arranged between two opposing flat wall surfaces facing each other, and the predetermined portion includes the predetermined section.

Abstract: A particle counter includes: a multi-flow cell with flow passages arrayed in a first direction and having a section including a detection region, for detecting a particle, formed when the flow passage is irradiated with irradiation light; a light receiving optical system configured to receive emitted light generated from a particle contained in sample fluid flowing in the at least one flow passage and passing through the detection region; an optical axis moving unit configured to move an optical axis of the irradiation light and an optical axis of the emitted light in the first direction; and a counter configured to count the particle for each particle size based on an intensity of the emitted light.

Abstract: An in-fluid floating substance measurement flow cell includes: a main body having at least a predetermined portion made of a material having translucency; and a flow passage formed inside the main body, having both end openings at an outer surface of the main body in a substantially identical direction, and configured such that fluid flows in the flow passage. The flow passage has a predetermined section arranged between two opposing flat wall surfaces facing each other, and the predetermined portion includes the predetermined section.