Selecting the Appropriate Test Sieve for Unconventional Applications
Sieve analysis, the cornerstone for fraction separation, gradation assessment, and particle size analysis, finds application across a vast spectrum of materials, from mineral soils and aggregates to pharmaceuticals, powdered metals, and dried food etc. Surprisingly, a multitude of sieve designs caters to the unique properties of these materials, aiming to provide precision and efficiency in testing.
Navigating the Realm of Test Sieves:
Traditionally, a "typical" test sieve is identifiable by its circular brass or stainless-steel frame, compatible with nesting other sieves, and mesh apertures ranging from 4 inches to No. 635 (100mm to 20μm). Th is classic design is considered suitable for most test sieving techniques and applications. Yet, before exploring non-traditional sieves, it's crucial to understand the fundamental attributes shared by all sieve varieties.
Mesh Precision
The most vital aspect of any test sieve is determined by the dimensions of its mesh apertures. Organizations such as ASTM, ISO, and AASHTO meticulously define these opening sizes and permissible tolerances. The choice of aperture sizes must fit the requirements of the testing method and the size spectrum of your sample material.
Brass and Stainless Steel
Brass and stainless steel are the common materials for sieve mesh. Brass, once favored in applications with sparking risks, has become pricier due to rising copper costs. In contrast, stainless steel shines in terms of longevity, wear resistance, minimal sample contamination, and cost-effectiveness. For precision sieving of fine powders, electroformed mesh takes center stage. Though costly and fragile, its ±1% to 2% opening tolerances offer unmatched accuracy.
Non-Metallic Meshes
Meshes made from non-metallic materials such as polyester or nylon are economical but lack durability and may fail to fit ASTM E11 or ISO 3310-1 standards. They are suitable for single-use or non-standard testing purposes and aid in avoiding sample contamination.
Mesh Precision
Similar to mesh, the materials used for sieve frames, whether brass or stainless steel, share advantages and disadvantages. Brass frames are resistant to sparking but have seen a rise in cost. In contrast, stainless steel excels in terms of durability, minimal contamination, and cost-efficiency. Its resistance to deformation ensures accurate and repeatable results. Frames crafted from plastic, specifically acrylic or polycarbonate, offer less durability compared to metal frames but provide the advantage of observing particle behavior for precise adjustment of agitation energy input. Moreover, these frames are resistant to corrosion and pose minimal risks of sample contamination. Acrylic frames undergo precise machining to guarantee a tight fit when stacked, reducing the ruin of sample material.
Frame Sizes
The internal size of a test sieve dictates the permissible sample volume, not the frame height or sample weight. Effective separation of fractions necessitates particles encountering multiple openings from different angles during agitation. When small frames contain large sample volumes, particles might not have enough chances to pass through mesh openings. Ideally, at the end of a test cycle, no more than one or two layers of material should be present on the surface of the mesh for optimal separation. Traditional circular test sieves are widely accessible in frame diameters of 8 inches and 12 inches (203mm an d 305mm) for ASTM E11 sieves or 200mm an d 300mm for ISO 3310-1 test sieves. It's important to note that ASTM and ISO sieve frames do not fit inside each other. Diameters can vary from 3 in ches (76mm) to as large as 18 inches (457mm), corresponding with ISO sieve options.
Frame Height
Careful consideration of sieve frame height significantly influences sieving accuracy, consistency, and lab pr oductivity. Frame heights ranging from 1-1/2 to twice the biggest particle size for each fraction offer adequate vertical clearance for particle mobility during the shaking process, ensuring multiple attempts at passing through mesh openings.
Full-height sieves are often used when dealing with coarse fractions. However, for finer fractions, intermediate or half-height sieves are suitable. These allow stacking more sieves in a set, reducing the stack's overall height for each test. This results in lesser test cycles and shorter time needed for a full gradation analysis. Additionally, in wet-wash sieving, increased frame height minimizes sample loss during the washing process.
By delving into the intricacies of test sieves, both conventional and non-conventional, you can select the ideal sieve for your specific needs. This ensures accurate results and streamlined operations in your laboratory.
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Why Do I Need an A lternative Sieve?
Non-conventional sieves manifest in diverse forms, each boasting distinct attributes that enhance functionality, precision, or cost-efficiency for specific methodologies, applications, or materials. The subsequent charts illuminate the distinguishing characteristics of several non-conventional sieves and delineate their respective applications.
ASTM Precision Electroformed Sieves
Properties :
- Sieves produced through the electroforming process exhibit extremely accurate and uniform mesh openings, with permissible variances falling within the ±1μm to 2μm range.
- These openings span from 5μm to 75μm and are available in both 3in and 8in stainless steel frames, with options for full or half-height configurations.
Test Standard :
- ASTM E161
- ISO 3310-3
Application :
- Accurate classification for fine granular materials and dry powders.
- Superior performance compared to woven-wire sieves in accurately sizing small-volume samples in cement, grain, pharmaceuticals, chemicals,, food, powdered metals, ceramics, and other applications.
- Well-suited for a wide range of vibratory sieve shakers
Additional Information :
- Custom electroformed sieves with specific opening sizes are available for purchase.
Micron Air Jet Test Sieves
Properties :
- Designed to be compatible with traditional Micron Air Jet Sieve units
- Equipped with unique sealing gasket in stainless steel frames with a diameter of 200mm.
- Available with ASTM E11-compliant stainless steel mesh ranging from No. 635 to No.4 (20μm to 4.75mm)
- Verification services offered for investigation or calibration grades.
Test Standard :
- ASTM E11
Application :
- Crafted to work seamlessly with conventional Micron Air Jet Sieves, utilizing small air pressure to separate dry powder samples ranging from 10 to 100g on a single sieve.
- Ideal for applications in pharmaceuticals and dry chemicals as well as ores, metal powders, aggregates, ceramics, cement, concrete, and coal materials.
Deep Frame Wet-Wash Sieves
Properties :
- Fabricated from either Stainless Steel or Brass / Stainless materials.
- Offered in frame depths ranging from 4 to 8 in ches and sizes spanning 3 to 12 inches.
- Brass Frames suitable for diverse applications.
- Stainless Steel frames present a cost-effective, durable, and sturdy option.
- Deep frames prevent sample loss during washing effectively
- Includes drainage holes in the bottom for efficient drainage.
Test Standard :
- ASTM E11
Application :
- Performing fines content evaluations or removing excess fines from samples before conducting sieve tests.
- Efficient for gentle wet separations of s ample specimens in industries like ores, aggregates, pharmaceuticals, chemicals, metal powders, ceramics, cement, concrete, and coal.
Replaceable Mesh Wet-Washed Sieves
Properties :
- Crafted from Stainless Steel or Brass / Stainless materials.
- Offered in frame depths ranging from 4 to 8 inches and diameters spanning 3 to 12 inches.
- Brass Frames are versatile for different applications.
- Stainless Steel frames offer a cost-effective, durable, and sturdy option.
- Deep frames prevent sample loss effectively during the washing process.
- Features drainage holes in the bottom skirt for efficient drainage.
Test Standard :
- ASTM E11
Application :
- Evaluating fines content or removing excessive fines from samples prior to sieve tests.
- Efficient for gentle wet separations of sample specimens in industries like pharmaceuticals, chemicals, ores, metal powders, aggregates, ceramics, cement, concrete, and coal.
Rocker Screen Set
Properties :
- The Rocker Screen comprises a 12-inch square steel box with a sloped bottom pan designed for manual rocking to enhance sample agitation.
- The frame can be equipped with interchangeable squares of stainless steel wire cloth, providing a wide range of ASTM E11 opening sizes.
Test Standard :
- ASTM E11
Application :
- Effectively separates large-grained samples for initial sorting or on-site grading of mineral aggregates, ores, coal, and other coarse materials.
Additional Information :
- Not advisable for application with mesh sizes lower than No. 20.
Two-Part Replaceable Mesh Sieves
Properties :
- 8-inch (203mm) diam eter frames are available in either brass or polycarbonate and are designed as two-piece assemblies.
- These frames maintain proper tension on polyester or nylon mesh squares when assembled together.
- The transparent polycarbonate frame units offer the advantage of sample visibility during testing and are resistant to corrosion.
- While they nest perfectly with each other, they are not compatible with other frame types. In contrast, brass frames can nest with each other or with standard metallic 8-inch frames.
Test Standard :
- The cloth square openings maintain consistency and are comparable to ASTM E11 standards, although they may not meet the specified tolerance requirements.
Application :
- Two-part frames are ideal for pairing with disposable non-metallic cloth, catering to diverse needs like nonstandard separations, initial sorting, or reducing the potential for sample contamination.
- Polyester cloth demonstrates strong wet stability, whereas nylon cloth boasts high tensile strength but might stretch under moisture exposure.
- These interchangeable mesh sieves are perfect for tasks involving dry chemicals, powders, sand, and soils.
3in Non-Metallic Sieves
Properties :
- Long-lasting polycarbonate frame sieves come equipped with polyester mesh, available in various opening sizes from 7μm to No. 50 (300μm).
- These sieves are crafted using a heat-cured adhesive construction technique, featuring a polyolefin band that covers the frame joint, guaranteeing a snug and secure nesting seal.
Test Standard :
- N/A
Application :
- Designed for manual operation exclusively, this lightweight and compact device is highly convenient for the separation of small quantities of fine materials such as pharmaceuticals, chemicals, food and grain products, and metal powders.
3in Acrylic Frame Sieves
Properties :
- Carefully crafted transparent acrylic frames are paired with ASTM E11 s tainless steel mesh, featuring aperture dimensions ranging from No. 3 ½ to No. 635 (5.60mm to 20μm). A lternatively, these frames can be equipped with ASTM E161 Pr ecision Electroformed cloth, offering openings varying from 150μm to 5μm.
Test Standard :
- ASTM E11
- ASTM E161
Application :
- Classifying and organizing particles within dry powders and fine granular materials, spanning from 5.60mm to 5μm, find applications in pharmaceuticals, chemicals, food and grain industries, and metal powders.
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