Particle counter
Inventors
Matsuda, Tomonobu • Minakami, Takashi • Sakaue, Daisuke • Shinozaki, Daisuke
Assignees
Publication Number
US-11262284-B2
Publication Date
2022-03-01
Expiration Date
2040-01-20
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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.
Core Innovation
The invention relates to a particle counter featuring a multi-flow cell arrayed in a first direction, each containing flow passages with a detection region where particles in a sample fluid are detected by irradiation light. The particle counter includes an irradiation optical system that irradiates a predetermined position within the flow passage and a light receiving system that detects emitted light generated from particles passing through this detection region. The optical axes of the irradiation light and the emitted light are movable along the array of flow passages to switch detection among multiple channels, and a counter counts particles for each size based on emitted light intensity.
The problem being addressed is that, in prior art particle counters where multiple flow cells are moved as a whole with fixed irradiation and light receiving optical systems, movement of pipes connected to the flow cells leads to loosening or cracking, which can cause sample fluid leakage and upsizing of the device due to pipe arrangement requirements at different surfaces. The present invention prevents leakage by fixing the multi-flow cell unit in place and moving only the optical axes, thus avoiding pipe movement and enabling a compact design.
Furthermore, the invention provides a focal point adjustment unit that adjusts the focal point of the light receiving optical system perpendicular to the flow cell array direction, improving accuracy in particle detection despite slight manufacturing variations. The positions for optical axis movement and focal point adjustment are stored in advance and correspond precisely to each flow passage, enabling automatic, high-precision alignment. The multi-flow cells are firmly fixed within the holder by pressure bushes ensuring accuracy in positioning, and each flow cell has a substantially rectangular solid shape with inlet and outlet ports on the same side, allowing pipes to be aligned on one surface to reduce device size and noise interference.
Claims Coverage
The patent includes seven independent claims covering the particle counter's structure, optical system movement, focal point adjustment, storage of positional data, multi-flow cell configuration, flow cell port arrangement, and emitted light properties.
Particle counter with movable optical axes and multi-flow cell arrangement
A particle counter comprising a light source emitting irradiation light, an irradiation optical system irradiating a predetermined position on an optical axis within multiple flow passages arrayed in a first direction in a multi-flow cell, a light receiving optical system with a light receiving axis orthogonal to the first direction, an optical axis moving unit that moves the optical axes of irradiation light and emitted light along the array, and a counter counting particles by emitted light intensity, with flow cells having a flow passage formed by first, second, and third flow passages and an incident surface for irradiation light entry.
Focal point adjustment of light receiving optical system
A focal point adjustment unit that adjusts the focal point of the light receiving optical system in the second direction perpendicular to the flow passage array.
Dual-actuator configuration for optical axis and focal point movement
The focal point adjustment unit includes a first actuator moving the light receiving optical system in the second direction, while the optical axis moving unit includes a second actuator moving the first actuator and irradiation optical system in the first direction.
Storage for precise positional control of optical axis and focal point
A storage stores predetermined first direction positions of the irradiation light and light receiving axes and the second direction focal point positions corresponding to each flow passage, enabling the optical axis moving unit and focal point adjustment unit to move to these stored positions upon channel selection.
Storage for positional control of optical axes
A storage configured to store first direction positions of irradiation light and light receiving axes with movement corresponding to the flow passage position.
Multi-flow cell with fixed flow cells in accurate positions
A configuration where multiple transparent flow cells with flow passages are arrayed, and each flow cell is fixed in close contact with reference portions of the multi-flow cell in first and second directions to ensure accurate positioning.
Rectangular flow cells with inlet and outlet ports on same side
Each flow cell is substantially rectangular and includes the sample fluid inlet and outlet ports at the same side surface.
Emitted light as scattered light or fluorescence
The emitted light received by the light receiving optical system is scattered light or fluorescence.
Detection region in first flow passage
The particle detection region is formed within the first flow passage.
Irradiation light enters flow cells at angle avoiding interference
Irradiation light enters one of the flow cells through an incident surface at a predetermined angle that allows passage through the detection region without interfering with the third flow passage.
The independent claims collectively cover a particle counter with a multi-flow cell structure where optical axes for irradiation and light reception move along fixed flow passages, optionally with focal point adjustment and stored positional data for precise movement, flow cells fixed accurately within a holder, inlet and outlet ports on the same side to enable compact pipe arrangements, and detection by scattered or fluorescent light generated in a defined detection region.
Stated Advantages
Leakage of sample fluid can be reduced by fixing the flow cells in place and moving the optical axes instead of the flow cells and connected pipes.
The particle counter can be downsized by arranging all pipes on one side due to the flow cells' substantially C-shaped flow passages configured with inlet and outlet ports on the same surface.
High accuracy in particle detection and particle counting is achieved by adjusting the optical axes of irradiation light and emitted light and the focal point in association with switching the flow passage.
Accurate positioning of each flow cell within the multi-flow cell reduces degradation in detection accuracy due to shifts in flow cell position.
Noise is reduced by setting the irradiation light to pass only through the first flow passage without interference with others, facilitating detection of fine particles with improved accuracy.
Documented Applications
Continuous measurement of multiple types of sample liquid containing particles by detecting scattered light or fluorescence from particles in flow passages arrayed in a particle counter.
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