60-Mesh and 80-Mesh Sieves: U.S. Standard Sieves No. 60 and No. 80 (Bureau of Standards, 1924)

Two standard testing sieves made the same way; only the wire and the opening change with the sieve number. Plain-woven brass or bronze wire cloth is soldered smoothly into a round frame about 20 cm (8 in) across. No. 60 has 0.250 mm openings (the 60-mesh sieve); No. 80 has 0.177 mm openings (the 80-mesh sieve). The finer the cloth, the finer the grains that pass. Source: Bureau of Standards, Letter Circular 74, Standard Specifications for Sieves (revised 1924). Unknown: the frame metal and the weaving. Picture: the Bureau's table.

متوسط

Unknown

التعليمات

Choose the sieve number

The sieve number sets the wire and the opening (Bureau of Standards table, 1924): No. 60: opening 0.250 mm (0.0098 in), wire 0.162 mm (0.0064 in). No. 80: opening 0.177 mm (0.0070 in), wire 0.119 mm (0.0047 in). The opening is the clear space between adjacent wires. No. 60 passes grains under 0.250 mm; No. 80 passes grains under 0.177 mm.

Weave the wire cloth

Weave plain (not twilled) cloth from brass, bronze or other suitable wire of the diameter for your sieve number, spacing the wires so the opening is as in the table each way. Ours: bronze wire. Not given: how it is woven.

المواد لهذه الخطوة:

سلك برونزي1 warp and shoot wires

الأدوات المطلوبة:

نول نسيج الأسلاك

Make the frame

Make a circular frame about 20 cm (8 in) across, with about 5 cm (2 in), or 2.5 cm (1 in), between its top and the cloth. Ours: brass strip. Not given: the frame metal.

المواد لهذه الخطوة:

شريط نحاس أصفر1 frame

الأدوات المطلوبة:

مقصّ صفائح

كاوية لحام

Mount the cloth

Mount the cloth on the frame without distorting it. Fill the joint between cloth and frame smoothly with solder, so the material being sieved cannot catch in it.

المواد لهذه الخطوة:

لحام قصدير-رصاص1 joint

مساعد صهر1 joint

الأدوات المطلوبة:

كاوية لحام

Check it against the tolerances

Measure the warp and shoot wires separately. For both numbers the average opening must be within ±6 % of the table, the average wire diameter within −15 to +35 %, and no opening may exceed the table opening by more than 40 %. Reject a sieve with punctures, loose or wavy cloth, poor soldering, or too many large openings.

الأدوات المطلوبة: