ISO/TR 23437-2020 pdf download.Solid biofuels一Bridging behaviour of bulk biofuels.
4.3 Test equipment
4.3.1 B ridging test apparatus.
A box with a bottom area (inside dimensions) of 1,1 m x 2,0 m and a minimum filling height of 0,75 m (±0,01 m) is used. These dimensions accommodate a required sample volume of 1,65 m3. The sides of the box are made of low friction coated plywood or similar. The two sections of the bottom of the box are made of flexible mats with low friction surfaces.
An expandable slot is formed between the two bottom sections of the box. The mat on each of the two bottom sections forms the slot in terms of a quarter of a circular arch with an effective radius of (32 ± 5) mm. The slot is closed when the two bottom sections are pushed together and the two mats meet in the centre of the length of the box. The mats are fully even and horizontal, except at the round edges (see Figure 3). The slot Is gradually expandable while the edges remain parallel and the bottom is prevented from becoming inclined during any phase of the opening procedure. The expansion is executed in a way that ensures the mats remain in place, except at the rounded edges where they can slide over a plate and form the rounded edges (see Figure 3). Thus, any friction between the bottom sections and the biofuel sample in the box is avoided when the slot is expanded.
NOTE Alternatively, the mats on the two bottom sections can wind onto rollers under each bottom section. Consequently, the effective radius becomes variable during the opening procedure. In this case, the mat is made of thin material.
The movements of the two bottom sections is synchronized (ganged) and simultaneous during the opening of the slot. The maximum width of the slot is 1,5 m across the bottom of the box. The edges of the slot remain parallel during the opening procedure. A tolerance of 10 mm is acceptable. This tolerance is measured as the difference of the opening width at both ends of the slot and it applies for the full range of the slot opening.
The opening speed is 180 mm/mm (±50 mm/mm) or lower. The drive mechanism for the movable floor allows for vibration-free, frequent and smooth starts and stops by the operator.
The box is positioned firmly at a height that ensures all sample materials fall freely through the slot without causing any blockages below on the floor (e.g. a height of 1,5 m of the box bottom above the floor).ISO/TR 23437 pdf download.