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Particle size distribution, median value, moisture content

Definition

Value for the mean particle size (50 % in weight of the dust is coarser and 50 % in weight is finer than the median value).

Determination

The particle size distribution of a dust is always determined by a screen analysis. To this effect, the dust to be tested is sieved onto standard test screens and the screen

residue is weighed. If a screen analysis cannot be carried out, wet or sifting methods are used to determine particle size distribution.

If the residue in weight per cent is plotted over the particle diameter in the Rosin-Rammler-Sperling-Bennet-(RRSB) grid, a distribution curve occurs, indicating the

median value of the tested dust. The median value can be used to roughly characterise the fineness of the dust sample.

The moisture content of the substance to be tested is measured as the difference between the weight of wet dust and the weight of dried dust. This is determined by

carefully drying the dust until a constant weight is achieved.

Remark

The fineness and moisture content refer to the state of the dust sample as delivered respectively as tested. The "delivered" state may be identical to the tested state. The

listed combustion and explosion characteristics always apply only to the dust with the conditions described in the same column.

If no data is provided on moisture content of the delivered state, it must be assumed that the substance has reached moisture saturation. Prepared testing samples, on

the other hand, consist of dried dust with a residual moisture usually of

Home > Results > Detailed Information > Explanations Combustibility

Combustibility

Definition

These test checks whether and to what extent a fire started by external ignition can spread in deposited dust.

Determination

An attempt is made to ignite the dust sample heaped to form a strip of product about 2 cm wide and 4 cm long at one end with a glowing platinum wire with a temperature

of about 1000 C. The wire is immersed only briefly in the dust sample, so that the latter is not heated. A 5 mm to 20 mm thick ceramic plate is used as a base. In the

case of melting substances, a modified combustion test is also carried out on a sample to which 20 % in weight kieselgur has been added. The result frequently indicates

obvious combustion behaviour.

The combustibilityis evaluated by the class numbers BZ 1 to BZ 6.

Combustibility BZ

Does not catch fire BZ 1

Catches fire briefly and extinguishes rapidly BZ 2

Local burning or glowing without spread BZ 3

Spread of a glowing fire BZ 4

Spread of an open fire BZ 5

Very rapid combustion BZ 6

Remark

The values specified in brackets refer to the modified combustion test with melting substances after admixing 20 % by weight kieselgur.

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Home > Results > Detailed information

Detailed information on:

Wood fibres, gluey (fibres dryer) (5613)

characteristic

Particle size

Home > Results > Detailed information

Detailed information on:

Wood (ca.90 % chipboard, ca 10 % pine), from shredder (7606)

characteristic

Particle size

Home > Results > Detailed information

Detailed information on:

Wood, from filter (7602)

characteristic

Particle size

Home > Results > Detailed information

Detailed information on:

Wood (chips/dust) (5298)

characteristic

Particle size

F2013-413 - Rev. A : Proj. AGRIMECCANICA FALCON 150/85.EVA.MD.WS

Y:\Offerte\2013\F2013\F2013-413\Rev_A\02_Offerta\F2013-413_A.doc pag.6/13 PAL S.r.l. considera questo documento riservato e di rilevante valore economico con divieto di utilizzarlo, riprodurlo o renderlo comunque noto a terzi o a concorrenti in tutto o in parte senza specifica autorizzazione scritta della direzione della PAL S.r.l.

Parametri di pericolosit Kst pmax, Pannelli antiesplosione AX 00.00.A 02ENLIVELLI STANDARDIZZATI DI PERICOLOSITA' DEI MATERIALI PROCESSATI CON IMPIANTI PAL

MC(1) MIT(2) MAST(3) Macchine Silos & filtri Gruppo materiali polverosi bd

%

C

C pmax(4)

bar Kst(5) barm/s

pmax bar

Kst barm/s

1) Materiali secchi per PB 1 Particelle da riciclo pannelli 2 Miscele di particelle da essiccatoi

3 Flussi di particelle dai vagli

1 Strato interno 2 Strato esterno 3 Polvere

4 Polvere di levigatura 5 Particelle-polvere da seghe 6 Scarto materassi 7 Scarto secco

2) Materiali secchi per MDF 10 Fibra dopo l'essiccatoio - non resinata 11 Polvere di levigatura 12 Fibra da seghe 13 Scarto materassi 14 Scarto secco

3) Materiali secchi per OSB 20 Fini per recupero fine 21 Polvere dai vagli del secco 22 Polvere di levigatura 23 Fini-polvere da seghe pannelli & taglio a misura

1

24 Scarto secco includendo polvere-fini da seghe pannelli & taglio a misura

< 8 300 200 10 200 10 200

1) Materiali secchi per PB 1 Grosso dal vaglio

2) Materiali semi-secchi per PB 2 Legno riciclato & chips 3 Fini da riciclo chips 4 Shavings secchi 5 Particelle resinate

3) Materiali semi-secchi per MDF 10 Riciclo chips 11 Fini da riciclo chips 12 Shawings secchi 13 Fibra resinata

4) Materiali secchi per OSB 25 Strands dopo l'essiccatoio

26

Strands da vagli del secco 1 Grosso 2 Strato esterno 3 Strato interno 4 Fini per riciclo fine

5) Materiali semi-secchi per OSB

2

27 Recupero di fine resinato

8 < 15 300 200 9 150 9 150

1) Materiali semi-umidi per PB-MDF-OSB 3

1

Tutti i materiali grezzi certificati 15% e