Variable Rate Particle Counter and Method of Use
First Claim
1. A variable rate volumetric particle counter comprising:
- a sample pump having a control input, a sample input and a sample output, the sample pump sample output having a sample volumetric delivery rate responsive to the sample pump control input;
a sheath pump having a control input, a sheath fluid input and a sheath fluid output, the sheath pump sheath fluid output having a sheath volumetric delivery rate in a laminar flow stream responsive to the sheath pump control input;
a flow cell coupled to the sample pump sample output and the sheath pump sheath fluid output so that the sample is drawn in a suspension stream of a fixed diameter into the sheath fluid stream;
a detection assembly comprising at least one sensor having an output indicative of a characteristic of the drawn suspension;
data analyzer for analyzing the detected characteristic with respect to predetermined criteria and determining control parameters to achieve the predetermined characteristic criteria;
sample rate controller coupled to the data analyzer and having a control output connected to the control input of the sample pump for controlling the sample pump to vary the sample volumetric delivery rate in response to the control parameters; and
sheath rate controller coupled to the data analyzer and having a control output connected to the sheath pump for controlling the sheath pump to vary the sheath volumetric delivery rate in response to the control parameters.
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Accused Products
Abstract
A variable rate particle counter for adjusting the volumetric delivery rate of fluid to a flow cell based upon an initial particle count rate in order to effectively “tune” the final dilution of sample sheath flow to the particle concentration of the sample. A sheath fluid syringe pump and a test sample syringe pump are driven by motors which are adjusted by a data analyzer. The data analyzer compares a particle count rate measured by a detection assembly to a predetermined reference value and determines if the count rate is too high or to low. Accordingly, one of several pump profiles is initiated to adjust the flow rate of the sheath fluid or test sample or both. Advantageously, the low cell count precision is improved and the upper limit cell count is expanded.
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Citations
18 Claims
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1. A variable rate volumetric particle counter comprising:
- a sample pump having a control input, a sample input and a sample output, the sample pump sample output having a sample volumetric delivery rate responsive to the sample pump control input;
a sheath pump having a control input, a sheath fluid input and a sheath fluid output, the sheath pump sheath fluid output having a sheath volumetric delivery rate in a laminar flow stream responsive to the sheath pump control input;
a flow cell coupled to the sample pump sample output and the sheath pump sheath fluid output so that the sample is drawn in a suspension stream of a fixed diameter into the sheath fluid stream;
a detection assembly comprising at least one sensor having an output indicative of a characteristic of the drawn suspension;
data analyzer for analyzing the detected characteristic with respect to predetermined criteria and determining control parameters to achieve the predetermined characteristic criteria;
sample rate controller coupled to the data analyzer and having a control output connected to the control input of the sample pump for controlling the sample pump to vary the sample volumetric delivery rate in response to the control parameters; and
sheath rate controller coupled to the data analyzer and having a control output connected to the sheath pump for controlling the sheath pump to vary the sheath volumetric delivery rate in response to the control parameters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- a sample pump having a control input, a sample input and a sample output, the sample pump sample output having a sample volumetric delivery rate responsive to the sample pump control input;
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12. A variable rate volumetric particle counter comprising:
- means for delivering a sample at a sample volumetric delivery rate;
means for delivering a sheath fluid at a sheath volumetric delivery rate in a laminar flow stream;
means for drawing the sample in a suspension stream of a fixed diameter into the sheath fluid stream;
means for detecting a characteristic of the drawn suspension;
means for analyzing the detected characteristic with respect to predetermined criteria and determining control parameters to achieve the predetermined characteristic criteria;
means for controlling the sample pump to vary the sample volumetric delivery rate in response to the control parameters; and
means for controlling the sheath pump to vary the sheath volumetric delivery rate in response to the control parameters. - View Dependent Claims (13, 14, 15, 16, 17)
- means for delivering a sample at a sample volumetric delivery rate;
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18-22. -22. (canceled)
Specification