| 摘要 |
A sheath flow device for an evaporation light scattering detector comprises an evaporation pipe fastener (110), an evaporation pipe heat insulating component (120), a sheath flow nozzle blocking plate (130), a sheath flow nozzle (140), a sheath flow sleeve (150), a sheath flow outlet piece (170) and a stainless steel spray needle (160). The evaporation pipe fastener, the evaporation pipe heat insulating component, the sheath flow nozzle blocking plate, the sheath flow nozzle, the sheath flow sleeve and the sheath flow outlet piece are concentrically connected orderly from front to back, and all provided with concentric inner holes. Said device is applicable to ELSD sheath flow devices ranging from nanoliter-scale to microliter-scale. On one hand, material particles entering a testing pool are enveloped and aggregated so that the formation of eddy and turbulence can be reduced, the chromatographic peak shape of a sample can be improved and the stability of sample detection can be enhanced; on the other hand, the testing pool can be cleaned so that baseline noise can be reduced and the signal to noise ratio can be increased. |
| 主权项 |
1. A sheath flow device for evaporative light scattering detector (ESLD) includes a fixing base for evaporating tube, heat insulating part for evaporating tube, a sheath flow baffle, a sheath flow nozzle, a sheath flow sleeve, a sheath flow outlet, and a stainless steel needle of nozzle. The above mentioned six parts have the same internal diameter and are concentrically connected according to the mentioned order. The inner-bore of the fixing base for evaporating tube and the heat insulating part for evaporating tube is equal to the external diameter of evaporating tube in ELSD. The inner-bore entry end of the sheath flow baffle has a step washer which has the same inner diameter as the external diameter of evaporating tube. The inner-bore of the said sheath flow nozzle is wide in the front and narrow in the back like a trumpet shape. The inner-diameter of the inlet of the sheath flow nozzle is as same as the inner-diameter of the sheath flow baffle's exit end and the inner-diameter of the outlet of the sheath flow nozzle is equal to the inner-diameter of the stainless steel needle. And there is a sheath gas entry across connected with its inner-bore of sheath gas sleeve. The front end of the stainless steel needle is welded to the outlet of sheath gas nozzle and the back end of the stainless steel needle is introduced into the inter-diameter of the hole in the outlet sheet passed through the sheath gas sleeve, meanwhile, flushed with the exit end of the sheath flow outlet. The inner diameter of the sheath flow outlet is approximately above the external diameter of the stainless steel needle, and it formed the sheath gas where it passed through the circular orifice between the outside-diameter of the stainless steel tube and the inside-diameter of the hole in the outlet sheet. |
