The GA-8 accepts up to seven 8in (203mm) full-height test sieves with ASTM E11 woven wire cloth or ASTM E161 Precision Electroformed Mesh. Units also accept ISO 565 and 3310-1 sieves using the required GAA-10 Ultrasiever Adapter Set for 200mm sieves.
Sieving action is created by 3,600 sonic pulses per minute from an audio energy generator oscillating the air column inside the sieve stack to agitate each particle. Sieving intensity (amplitude) is set through a proportional controller. A programmable ramping feature increases amplitude incrementally to the maximum rate and holds it, then reduces it back down for optimum separation. Horizontal and vertical tappers aid the passage of near-size fines. Horizontal tappers can be positioned to tap on selected sieves. Four vertical tappers can be operated as one pair for most materials or two pairs for difficult samples.
The memory stores up to ten programs with specific amplitude, ramping, tapping and test duration settings for specific materials. Test times vary depending on material type and particle size. Typical sieving time is 1 to 5 minutes, but operating time can be set for up to 99.9 minutes.
The powder-coated steel case has vertically-hinged LexanTM doors enclosing the sieve chamber. Sample material is contained by flexible top and bottom diaphragms. The stack is sealed when the upper enclosure containing the audio generator is lowered into place. When test is complete, fines are recovered from the bottom diaphragm.
Sieves are ordered separately. ASTM E11 sieves from 1/4in to No. 635 (6.3mm to 20µm) or ASTM E161 sieves with precision electroformed mesh from 150 to 5µm with tolerances of ±2µm can be used. 200mm and 300mm diameter ISO 565 and 3310-1 sieves are also available for ordering and must be used with the GAA-10 UltraSiever Adapter Set for 200mm sieves.
- Accurate separations for samples up to 100g
- Accepts seven full-height 8in or 200mm diameter sieves
- Fully programmable time, amplitude and vertical or horizontal tapping sequences promote repeatability
- Storage of up to ten programs with amplitude, ramping, tapping and test duration settings
- Compliant with multiple ASTM and AASHTO standards