Reaction cuvette wash unit

#This application claims the priority of the Chinese patent application No. 200610063323.0, filed on Oct. 26, 2006, entitled “REACTION CUVETTE WASH UNIT”, the disclosure of which is incorporated herein by reference in entirety.

#The present invention relates to a wash unit for use in automated chemistry analyzer, and more particularly to a wash unit which functions cooperatively with a reaction tray in a manner to implement automatic cleaning of the reaction cuvette by a set of gas-liquid path system.

#The existing automatic wash unit for a full-automatic biochemical analyzer comprises a motor and multiple sets of cleaning needle components, at least one of which has a wipe nozzle. Driven by the motor, the wipe nozzle of the cleaning needle component gets access into the reaction cuvette while the reaction tray pauses, touches the bottom of the cuvette, and rises without the reaction cuvette after a rather short period of time, thereby fulfilling the cleaning of the reaction cuvette. However, this wash unit suffers from the following shortcomings. As there is no anticollision mechanism, the wipe nozzle may easily collide with the wall of the cuvette when it gets access into the reaction cuvette, thereby making the wipe nozzle, cleaning needles and the reaction cuvette damaged. Moreover, the existing structures are rather complicated. They either move unevenly, or fail to perform the power-off self-locking in the vertical direction, or are compromised by a high cost.

#FIG. 1 is a front view of a reaction cuvette wash unit according to the present invention.

#FIG. 2 is a stereogram of a cleaning needle assembly of the reaction cuvette wash unit according to the present invention, viewed from the front.

#FIG. 3 is a schematic view of the partial structure of the cleaning needle assembly of the reaction cuvette wash unit according to the present invention.

#Referring to FIG. 1, in this embodiment, the reaction cuvette wash unit comprises a supporter 1 and eight sets of cleaning needle components 2 mounted on the support 1, a power unit 3 and a driving device 4. As shown in FIG. 2, the supporter 1 includes an upper supporting plate 11 and a lower supporting plate 12, which are both positioned horizontally and have a certain distance in height. The upper and lower plates 11 and 12 are fixedly joined as an integral part by a junction plate 13 positioned vertically, as shown in FIG. 4. The upper supporting plate 11 has eight upper mounting holes spaced thereon in a row, while the lower supporting plate 12 has eight lower mounting holes spaces thereon in a row. Eight upper mounting holes are aligned with those eight lower ones respectively, thus forming eight sets of mounting holes for mounting the cleaning needle components 2. The lower supporting plate 12 also provides eight locating pins 121 protruding upwardly, as shown in FIG. 3.

#As shown in FIG. 2, eight sets of cleaning needle components 2 each comprise cleaning needles 21, a needle sheath 22 and a sheath holder 23. Each cleaning needle component 2 has two cleaning needles 21, which are an suction needle 211 and a drainage needle 212 respectively. The needle sheath 22 nests and adheres to the suction needle 211 and the drainage needle 212 by glue. The sheath holder 23 is fastened to the middle of the needle sheath 22 by a fastening screw 28, and has thereon a pinhole 231 at a position corresponding to the locating pin 121. These eight needle sheaths 22, which are fixedly joined with cleaning needles, fit with each of these eight sets of mounting holes in a manner like the fit of a shaft and a hole, and this fit pertains to a clearance fit, thereby enabling these eight needle sheaths to move up and down vertically with respect to the supporter (i.e. the direction of gravity). Eight locating pins 121 are inserted into eight sheath holders' pinholes 231 respectively, thus preventing cleaning needles from rotating. Each of the eight needle sheaths is nested by a spring 24, the upper end and the lower end of which sustain the upper supporting plate 11 and press against the corresponding sheath holder 23 respectively, while each of the sheath holders 23 in turn presses against the lower supporting plate 12. Because the dimension of each sheath holder 23 is greater than that of the corresponding lower mounting holes provided on the lower supporting plate 12, each of these cleaning needle components 2 would not disengage with the supporter 1 from the bottom under gravity.

#The automatic cleaning process for the reaction cuvette requires that two cleaning needle component should have a wipe nozzle 26 mounted on each cleaning needle therein. Since the dimension of the wipe nozzle 26 approaches to that of the intracavity of the reaction cuvette, the gap between the wipe nozzle and the inwall of the reaction cuvette is rather small where the cleaning needles reach downward into the reaction cuvette. In order to protect the wipe nozzle, cleaning needles and the reaction cuvette, one of these two sets of cleaning needle components is provided with a baffle palte 25, which is fixedly mounted on one of the sheath holders 23. For this cleaning needle component, the baffle plate 25, the cleaning needles 21, the needle sheath 22 and the sheath holder 23 are fixedly joined as an integral part. The lower supporting plate 12 has thereon a photoelectric sensor 14 corresponding to the baffle plate 25. The photoelectric sensor 14 including an induction slot 141 is fixed on a sensor mounting holder 15 which is further secured to the lower supporting plate 12, as shown in FIG. 3 and FIG. 4. The induction slot 141 of the photoelectric sensor is located in the pathway of the vertical up-and-down movement of the baffle plate 25. That is, the projection of the baffle plate 25 on the horizontal plane is at least partially within the projection of the induction slot 141 on that plane. At the initial position, the induction slot 141 is located above the baffle plate 25.