|
Grade |
Comments |
Weight (g/m2) |
Thickness (mm) |
Flow Time*1 (sec) |
Absorption speed*2 (cm) |
Wet Strength*3 (kPa) |
Nominal Rating (µm) |
Collection Efficiency (%, 0.3 |
Conversion*4 |
|
|
Whatman |
ex-Schleicher & Schuell |
|||||||||
|
No. 1 |
Retains large crystalline particles and gelatinous precipitates. Fast flow rate, smooth surface, normal hardness |
90 |
0.20 |
45 |
9.0 |
7 |
6 |
65 |
4 |
410 |
|
No. 2 |
Retains medium crystalline precipitates, fast flow rate, smooth surface, normal hardness |
125 |
0.26 |
80 |
8.0 |
8 |
5 |
80 |
- |
604 |
|
No. 231 |
Retains crystalline precipitates, moderate flow rate, smooth surface, normal hardness |
95 |
0.18 |
130 |
7.5 |
- |
(Medium) |
- |
2 |
- |
|
No. 232 |
Retains medium to medium- fine particulates, slow flow rate, smooth, normal hardness |
90 |
0.18 |
250 |
5.0 |
- |
(Med./ Med.-Fine) |
- |
6 |
- |
|
No. 131 |
High retention efficiency for fine crystalline precipitates like barium sulfate, slow flow rate, smooth surface, normal hardness |
140 |
0.25 |
240 |
6.0 |
8 |
3 |
90 |
3 |
597 |
|
No. 235 |
Highest retention efficiency, retains very fine particulates, very slow flow rate, smooth |
95 |
0.17 |
1,200 |
4.0 |
- |
(Very Fine) |
- |
5 |
- |
|
No. 101 |
Seed germination, retains large particles |
80 |
0.21 |
50 |
8.0 |
34 |
5 |
- |
91 |
- |
*1. Flow time is the time in seconds required to filter 100 mL of distilled water at 20°C under pressure supplied by a 10 cm water column through a 10 cm2 section of filter paper.
*2. Absorption speed is the distance in cm that water will travel in an upright strip of filter paper in ten (10) minutes at 20°C.
*3. Wet strength is the pressure measured by Mullen Burst Strength Tester after soaking in water.
*4. Conversions between manufacturers are not absolute. Use these conversions as a guideline.
• Available in discs in the following diameters (mm): 55, 70, 90, 110, 125, 150, 185, 240, 285, 300, 330, 360, 400, 500, 600
• Additional sizes available upon request.
• Order by specifying first the grade of filter then the diameter, e.g. (No.1, 125 mm), (No.232, 55 mm)
• Package of 100
