BS ISO 556:2020 pdf download – Coke (greater than 20 mm in size) — Determination of mechanical strength
The drum shall have an opening on the cylindrical surface through which the coke is charged and discharged. The opening shall be fitted with a cover, the inner portion of which shall be of 10 mm steel plate of the same curvature as the drum, and which shall be of the same size as the opening so that when the cover is secured, the inside face is substantially level with the internal surface of the drum.
A rubber gasket should be fitted around the cover to minimize loss of dust. Inside the drum, parallel to its axis and dividing the wall into four equal areas, four angle sections (or lifting flights) shall be fixed. Each lifting flight (for dimensions see Table 2), equal in length to the length of the drum, shall be fixed rigidly to the full length of the internal curved surface of the drum.
The position of the lifting flights is parallel to the axis of the drum in such a way that the flange of width 100 mm points towards the axis of the drum, and the narrower flange, in contact with the curved surface of the drum, points in the direction opposite to that of rotation of the drum. Drum wall thickness and lifting flight thickness should be measured after every 500 tests to ensure conformity to specifications.
The drum shall be replaced if the wall thickness falls below 5 mm due to wear. The angle sections (or lifting flights) shall be replaced when they wear to 95 mm. The drum shall be carried on two stub-axles, at least 250 mm in length, rotating in horizontal journal bearings which are supported in a framework mounted at either side of the drum. The clearance below the drum shall be not less than 230 mm and not more than 300 mm to enable the drum to be conveniently emptied. The drum shall be capable of being rotated in either direction to facilitate emptying. An electric motor shall be used to set the drum in motion at a constant rotational frequency of (25 ± 1) min −1 and the drum shall be fitted with a revolution counter and relay system, which may be pre-set to stop the drum after any desired number of revolutions.
5.2 Tray, >1 000 mm × >900 mm × 200 mm deep, constructed from a suitable abrasion-resistant and wear-resistant material for receiving the coke on discharge. One end wall of the tray shall be inclined outwards at 45° to facilitate emptying.
NOTE 1 Trays of approximately 1 500 mm × 1 100 mm × 200 mm deep were found to be suitable. NOTE 2 1,22 mm galvanized sheet has been found suitable for the tray.
5.3 Weighing machine, preferably of the platform type, of maximum capacity 100 kg (50 kg for half Micum or half Irsid test) and such that the weighing error does not exceed 0,1 kg (0,05 kg for half Micum or half Irsid test).
5.4 Round-hole test sieves, comprising a series of perforated plates with circular apertures (ISO 3310-2) that will enable a complete size analysis of the coke under examination to be determined. Test sieves with apertures of diameter 10 mm, 20 mm and 40 mm shall be included. Others in the series may be, for example, 31,5 mm, 60 mm, 80 mm and 100 mm. It is important to check the sieves from time to time (e.g. after 500 sievings) using the methods described in ISO 3310-2, to ensure that the hole dimensions are within the specified tolerances. Worn or damaged sieves could give rise to serious errors in size analysis and shall be discarded.
5.5 Series of light containers, the largest of which shall be capable of holding 50 kg of coke (i.e. capacity of at least 0,12 m 3 ) for the handling and collection of all different sieve fractions. 6 Sample preparation A gross sample shall be taken consisting of approximately 100 kg of coke according to ISO 18283 or ISO 13909-6. The lower size limit shall be not less than 20 mm, but where the lower nominal size of the coke sample is greater than 20 mm, this lower nominal size may be used for the preparation of a Micum test portion (see 8.2).
This sample shall be subjected to a size analysis according to ISO 728. In Table 3 a set of suitable sieves is given. Sieves of 10 mm, 20 mm, and 40 mm are mandatory for bottom sizes >40 mm, >20 mm and sievings after test. Other sieves are optional.