Specimen Nozzle Dispensing for Accurate Small Volume Ejection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automatic analyzers face challenges in accurately dispensing small amounts of viscous biological specimens, such as whole blood, due to the large outer diameter and sharp tip of specimen nozzles, which lead to difficulties in specimen separation and carry-back issues.
Innovation Solution
The implementation of a specimen dispensing mechanism that uses a specimen nozzle with a downward-facing tip end and a syringe pump, along with a cleaning and water droplet removal system, to accurately dispense small volumes of specimens by first filling the nozzle with cleaning water, then system water, and finally the specimen, ensuring accurate ejection without carry-back.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the specimen nozzle has a large outer diameter and sharp tip end to reduce insertion load on the rubber cap, then the insertion load is reduced, but the force of ejection is decreased and specimen carry-back occurs
Solution Approach 1:
The patent changes the geometric parameters of the specimen nozzle, specifically setting the tip end angle α to 30 degrees or more (preferably 45 to 60 degrees) and the outer diameter to 0.5 mm or more. This parameter optimization balances the insertion load reduction with adequate ejection force, preventing specimen carry-back while maintaining easy penetration of the rubber cap.
2Force
If the specimen nozzle has a large outer diameter to reduce insertion load, then the insertion load is reduced, but the specimen cannot separate from the tip end of the nozzle
Solution Approach 1:
The patent optimizes the tip end angle parameter α to be 30 degrees or more, which creates an appropriate balance between nozzle diameter and specimen separation. This angular parameter change ensures that the specimen can detach from the nozzle tip after ejection, preventing carry-back issues that would occur with sharper angles.
3Force
If the opening of the specimen nozzle is inclined to the bottom surface of the reaction chamber to increase ejection force, then the ejection force is improved, but it becomes difficult for the specimen to separate from the nozzle tip end
Solution Approach 1:
The patent specifies that the tip end angle α (the angle between the axial direction and the tip end surface) should be 30 degrees or more. This parameter control ensures that even when the nozzle is inclined for optimal ejection force, the specimen can still separate from the tip end due to the appropriate angular geometry, preventing carry-back.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables precise dispensing of small specimen volumes without relying on nozzle shape or specimen viscosity, effectively preventing carry-back and ensuring accurate specimen distribution on the reaction chamber surface.
Implementation Method 1
a syringe pump, along with a cleaning and water droplet removal system, to accurately dispense small volumes of specimens by first filling the nozzle with cleaning water, then system water, and finally the specimen
Implementation Method 2
a liquid pump which is connected to the probe so as to suction a sample out of the sample chamber
Implementation Method 3
the liquid and a part of the specimen are ejected onto a bottom surface of the reaction chamber
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a specimen dispensing mechanism 12 that includes a specimen nozzle 12a dispensing a specimen to be analyzed in a specimen chamber 15 to a reaction chamber 2 by suctioning and ejecting the specimen, and the specimen dispensing mechanism 12 is controlled so as to perform a specimen suctioning process of inserting the specimen nozzle 12a into the specimen chamber 15 and suctioning the specimen in the specimen chamber 15, a liquid suctioning process of suctioning a liquid by the specimen nozzle 12a after the specimen suctioning process, and an ejection process of ejecting the liquid and a portion of the specimen to the empty reaction chamber 2 from the specimen nozzle 12a in this order. Thereby, it is possible to provide an automatic analyser and a method which are capable of dispensing a small amount of specimen with a high level of accuracy, without depending on the outer shape of a specimen nozzle or the viscosity of the specimen.