Filter Paper Whatman
Qualitative Grades – Circles
|
Grade |
Flow Rate | Retention Microns | Wet Strength | Thickness mm | Ash % | |
| 1 | The most widely used general purpose paper | Medium/Fast | 11 | L | 0.18 |
0.06 |
|
2 |
Slightly thicker and more retentive than No1 | Medium/Fast | 8 | L | 0.19 | 0.06 |
| 3 | Double the thickness of No.1 | Medium | 6 | M | 0.39 |
0.06 |
| 4 | Excellent retention of coarse and gelatinous precipitates | Fast | 20-25 | L | 0.21 |
0.06 |
| 5 | Will retain fine precipitates, grained surface | Slow | 2.5 | L | 0.20 |
0.06 |
| 6 | Faster than No.5 but almost as high retention | Slow | 3 | L | 0.18 |
0.20 |
Quantitative Grades – Circles
|
Grade |
Flow Rate | Retention Microns | Wet Strength | Thickness mm |
Ash % |
|
|
Ashless |
General Purpose gravimetric paper | Medium | 8 | L | 0.20 | 0.01 |
|
Ashless |
For filtration of coarse and gelatinous precipitates | Fast | 20-25 | L | 0.19 |
0.06 |
|
Ashless |
Highly retentive for fine precipitates | Slow | 2.5 | L | 0.20 | 0.01 |
|
Ashless |
Intermediate retention and flow rate between Nos 40 and 41 | Medium/Fast | 16 | L | 0.21 |
0.01 |
|
Ashless 44 |
Thin version of No. 42 | Slow | 3 | L | 0.17 | 0.01 |
|
Hardened |
For retention of finest crystalline precipitates. Highly glazed surface | Slow | 2.7 | H | 0.12 |
0.025 |
|
Hardened |
General purpose hardened grade |
Medium | 7 | H | 0.17 |
0.025 |
| Hardened 54 |
For filtration of coarse and gelatinous precipitates | Fast | 20-25 | H | 0.18 |
0.025 |
