Open Flash

Methods of test for petroleum and its products. Determination of open, flash and fire point. Pensky-Martens method. 

Thermometer shall be an ASTM Open Flash-Type, graduated in either centigrade (—6° to +400°C) or Fahrenheit (+20° to +760°F) degrees and conforming to the requirements for thermometer 11C or 11F, respectively, as prescribed in ASTM El Procedure... 

The three common types of mold designs are open flash, fully positive, and semipositive. 

The semipositive mold (Figure 2.2c and d) combines certain features of the open flash and fully positive molds and makes allowance for excess powder and flash [4]. It is also possible to get both horizontal and vertical flash. Semipositive molds are more expensive to manufacture and maintain than the other types, but they are much better from an applications point of view. Satisfactory operation of semipositive molds is obtained by having clearance (0.025/25 mm of diameter) between the plunger (top force) and the cavity. Moreover, the mold is given a 2-3° taper on each side. This allows the flash to flow on and the entrapped gases to escape along with it, thereby producing a clean, blemish-free mold component. 

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