METHODS OF CHECKING WIRE CLOTH SIEVES TO DETERMINE WHETHER THEY CONFORM TO SPECIFICATION

 APPENDIX -II

METHODS OF CHECKING WIRE CLOTH SIEVES TO

DETERMINE WHETHER THEY CONFORM TO SPECIFICATION

Every opening in the metal wire cloth in a test sieve shall be eligible for inspection for compliance

with the requirements listed in the table.

When a Sieve has 20 openings or less, all openings shall be measured. In other cases the examination

Shall proceed in stages from a survey of general condition to methodical scrutiny of individual

openingS, and finally to measurement of opening size for compliance with the tolerances.

Test-1: Examination of General Condition of the Wire Cloth

For this purpose the sieve cloth shall be viewed against a uniformly illuminated background. If

obvious deviations from Table, for example weaving defects, creases, wrinkles, foreign matter in the

cloth, are found, the sieve is unacceptable.

Test-2: Examination of Openings For Tolerance

The observer shall carefully and methodically examine the appearance of all the openings, in order

to detect oversize openings. Openings whose width deviates by about 10% of the average value are

apparent to the unaided eye of a skilled observer. By this method, known as the "handicap method",

it is probable that all oversize openings exceeding the average value by about 10% or more will be

detected. At the same time it is easily possible to detect sequences of large openings, and local

irregularities in the weaving, appearing as distortions of the openings. If one opening is found to be

oversize by more than the maximum permissible limit X, the sieve is unacceptable.

Test-3: Assessment of Openings Exceeding the Intermediate Limit of W+7

Those openings whose width is between the limits of w+Z and w+X (See Note) shall be counted, or

their proportion of the total number or opening determined from representative sample regions. If

these openings exceed the permissible limits, the sieve is unacceptable.

Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves,Wire Cloth and Sieves for Testing Purposes

Test-4: measurements of the average size of Opening and Average Diameter of Wire

After a sieve has been found acceptable by the above tests, measurement of the average size of

opening and diameter of wire shall be made on sample regions. These average values Shall lie within

the prescribed limits given in Table 3.2.

The average size shall be measured over at last 10 openings, if available, in each direction in each of at least two positions on the cloth. If the results from the two fields fall in different tolerance bands and if they contradict the information from the Table, the average sizes at more positions on the

cloth shall be checked.

Responsibility for Inspection:

Unless otherwise specified in the contract or purchase order, the producer is responsible for the

performance of all inspection and test requirements specified herein. Except as otherwise specified

in the contract or order, the producer may use its own or any other suitable facilities for the

performance of the inspection and test requirements specified herein, unless disapproved by the

purchaser. The purchaser shall have the right to perform any of the inspections and tests set forth in

this specification where such inspections are deemed necessary to ensure that material conforms to

prescribed requirements.