The S291 Electronic Photofluorometer is specially designed to carry out fluorescence  measurements faster and easier with higher accuracy. It has unique features like the zero and  calibration adjustment with fine sensitivity potentiometer and digital display. The S291 can be used also for ultraviolet and thermal stability tests on liquid penetrants. It can  also be used to measure the fluorescence of fluorescent and dual colored magnetic powders. Measure of fluorescent brightness of penetrants as requested by AMS 2644 (replacing MIL-I- 25135), ASTM E-1417 (replacing MIL-STD-6866), EN ISO 3452-2. The NDT S291 is listed in  ASTM E-1135 and completely meets the EN 571-2.

荧光渗透液的日常检测的二个重要参数是：

含水量和荧光亮度，关于这个亮度的检测是非常重要的，通常3个月检测一回，需要使用如下仪器：

NDT FPI日常检测时，指定的S-291型荧光亮度计是严格按照标准AMS 2644（代替MIL-I-25135），ASTM E 1417（代替MIL-STD-6866）的要求测量荧光渗透剂的荧光亮度。意大利NDT公司S-291荧光亮度计同时完全符合ASTM E 1135和EN 571-2等标准的要求，是目前国际机构认证的检测荧光渗透剂的荧光亮度的仪器。NDT S291荧光亮度计是一种实验室用仪器，为测量荧光亮度而设计，更快捷、更简便，精度高。其特点是零点和刻度可调，带有高灵敏度的电位计和数字显示屏。

• Sample Holder — Designed for insertion in the sample slot on the front of the  photofluorometer. The sample holder comes with the instrument. 

• Primary Light Filter — The primary light source filter for the S291 photofluorometer is  an integrally filtered long-wave 4-W lamp. 

• Secondary Light Filters — The S291 uses an OGR green and OB14 blue glass filter  that is pre-installed. • All filters are installed by the manufacturer, so the instrument is ready for use. 

1. Turn on the instrument and allow a 10 to 15 minute warm up. 

2. Compare the prepared papers under the black light and choose one of the brightest  papers to set the instrument. 

3. Place the chosen paper in the sample holder and insert the holder into the sample  port of the photofluorometer. 

4. Adjust the meter response to 80 by turning the “CAL” adjustment knob. 

5. Remove the sample holder and replace the fluorescent paper with an untreated  blank paper and re-insert into the instrument.

6. Adjust the meter response to 00 by turning the “Zero” adjustment knob.

7. Remove the blank paper and insert the prepared sample for measurement. Alternate  samples of test and standard material to minimize effect of any instrument drift that  might occur.