- Qualitative analysis
- Low ash content 0.06%
- Untreated
- Consistent performance
- Wet-strengthened grades
available
- Custom cut
- Bulk packaging
|
Standard qualitative filter papers are suitable for quadrant folded or gravity flow applications. These
grades contain a high level of alpha-cellulose that provides high purity but will weaken when wet.
The inherent strength of standard (untreated) grades does not pose a problem when they are used in
routine quadrant folded applications. We do not recommend these grades for use in vacuum work or
when wet handling is required.
- Ahlstrom 610: 1.5μm – Slow Speed
This grade is a slow flowing filter designed to retain
fine particles encountered in qualitative analysis.
Ahlstrom 610 is widely used for water analysis,
biological products and fine precipitates such as coldprecipitated
barium sulfate. Ahlstrom 610 is also
used in Buchner funnels and to clarify cloudy
suspensions.
- Ahlstrom 642: 2μm – Medium Speed
This grade has finer particle retention than Ahlstrom
601 but with slightly lower filtration speed. Ahlstrom
642 also has higher absorption than Ahlstrom 601. It
is used in general laboratory applications to retain
particles above 2 μm in size. Ahlstrom 642 is also
found in agricultural and environmental laboratories
for plant growth trials, soil testing, and air analysis
for monitoring specific contaminants and in the
filtration of organic and sulfide precipitates.
- Ahlstrom 601: 2.5μm – Medium Speed
This grade covers a wide range of laboratory
applications and is used for clarifying liquids and for
rapid filtration of coarser precipitates such as lead
sulfate, lead chromate, calcium oxalate, calcium
carbonate, aluminum phosphate, barium carbonate
and beryllium hydroxide. Ahlstrom 601 can be found
in soil analysis, seed testing and in air pollution to
collect dust-laden air and is also commonly used in
the food industry to separate foodstuffs from
associated liquid or extracting liquid.
- Ahlstrom 237: 3μm – Medium Speed
This high absorbency grade is twice as thick as grade
642 with similar particle retention. The superior
absorbency offers excellent performance when used
as a sample carrier. The extra thickness gives higher
wet strength and loading capacity, enabling more
precipitate to be held without clogging the filter.
Ahlstrom 237 is also highly suitable for use in
Buchner funnels and for dye filtration.
- Ahlstrom 609: 4μm – Medium Speed
This grade is an evolution of Ahlstrom 613 for use in
the beer industry. This is a filter paper with an
extremely low iron and nitrogen content for the
analysis of protein in beer.
- Ahlstrom 613: 6μm – Medium Speed
This is a strong filter paper with a medium flow rate
and retention. Ahlstrom 613 is commonly used in
student laboratories. This strong general-purpose
filter is also useful in Buchner funnels for barium
carbonate, lead chromate and beryllium hydroxides.
- Ahlstrom 631: 10μm – Medium Speed
This grade is used for the filtration of coarse particles
and gelatinous precipitates such as ferric aluminum
and magnesium hydroxides. Ahlstrom 631 is used in
air monitoring and gas filtration when high flow rate
is needed. This grade is also found in routine cleanup
analysis of insoluble liquids such as biological fluids
and organic elements.
- Ahlstrom 615: 25μm – Fast Speed
This fast filtering grade is an intermediate grade
between Ahlstrom 617 and Ahlstrom 631. Ahlstrom
615 has a rough surface and is used for filtering
aluminum, ferric and magnesium hydroxides. It is
also found in general construction filtration work and
in the filtration of insoluble iron and ore.
- Ahlstrom 617: 35μm – Fast Speed
This is an extremely fast filtering grade and has a
larger particle retention than Ahlstrom 631. Ahlstrom
617, a thicker filter paper with higher loading
capacity, is used for rapid filtration of coarse particles
and gelatinous precipitates such as in oils and resin
solutions. Ahlstrom 617 is also found in construction
product testing and is used by students to retain
large flocculents and precipitates.
|
| Standard Grades |
Retention in µm |
Filtration Speed
Herzberg sec/100mls |
Filtration Speed
Rapidity mls/min |
Loading
capacity |
Whatman Cross
Reference |
| 610 |
1.5 |
1724 |
4 |
Medium |
5 |
| 642 |
2.0 |
229 |
30 |
Medium |
2 |
| 601 |
2.5 |
124 |
55 |
Medium |
1 |
| 237 |
3.0 |
114 |
60 |
Very High |
3 |
| 609 |
4.0 |
98 |
70 |
Medium |
- |
| 613 |
6.0 |
114 |
60 |
Medium |
Student Grade |
| 631 |
10.0 |
34 |
200 |
High |
4 |
| 615 |
25.0 |
29 |
235 |
High |
- |
| 617 |
35.0 |
19 |
360 |
Very High |
- |
Qualitative wet-strengthened grades are manufactured for applications using filter paper in a system or
apparatus that operates under pressure or vacuum conditions. These systems require the use of
extremely strong filter paper such as those in Ahlstrom’s Binder Series. These grades contain a small
amount of chemically stable, insoluble binding resin that strengthens the natural fiber-to-fiber bonds
under wet conditions. Grades containing wood fibers or resins containing nitrogen are not
recommended for use in quantitative ashing techniques, or in Kjeldahl estimations. Ahlstrom’s
qualitative wet-strengthened filter papers are also used in industrial laboratories where technicians
require a strong and economical filter paper with consistent quality and performance.
- Ahlstrom 950: 2.0μm – Slow Speed
This slow flow rate grade with very good retention is
used in the filtration of fine precipitates and super
phosphates. Ahlstrom 950 is also recommended for
boiler water analysis applications and gas filtration.
- Ahlstrom 909: 3.0μm – Medium Speed
This medium flow rate grade with very good
retention is a tighter version of Ahlstrom 962. This
grade has a rough surface and is often found in the
food industry for routine tests.
- Ahlstrom 962: 27μm – Fast Speed
This fast filtering grade is a thinner version of
Ahlstrom 961. Ahlstrom 962 is recommended for the
filtration of coarse and gelatinous precipitates. The
creped surface of Ahlstrom 962 also offers higher
surface area to maintain high filtration speed.
- Ahlstrom 961: 40μm – Fast Speed
This fast filtering grade, with extremely high loading
capacity, is recommended for the filtration of coarse
and gelatinous precipitates. The creped surface of
Ahlstrom 961 also offers higher surface area to
increase filtration speed.
|
| Wet-Strength Grades |
Retention in µm |
Filtration Speed
Herzberg sec/100mls |
Filtration Speed
Rapidity mls/min |
Loading
capacity |
Whatman Cross
Reference |
| 950 |
2.0 |
491 |
14 |
Medium |
6 |
| 909 |
3.0 |
105 |
65 |
Medium |
91 |
| 962 |
27.0 |
28 |
245 |
High |
114 |
| 961 |
40.0 |
19 |
360 |
Very High |
113 |
| (100/box; item with grade numbers in
bold are 50/box) |
| Size* |
237 |
601 |
609 |
610 |
613 |
615 |
617 |
631 |
642 |
| 2.5 |
2370-0250 |
6010-0250 |
6090-0250 |
6100-0250 |
6130-0250 |
6150-0250 |
6170-0250 |
6310-0250 |
6420-0250 |
| 4.25 |
2370-0425 |
6010-0425 |
6090-0425 |
6100-0425 |
6130-0425 |
6150-0425 |
6170-0425 |
6310-0425 |
6420-0425 |
| 4.7 |
2370-0470 |
6010-0470 |
6090-0470 |
6100-0470 |
6130-0470 |
6150-0470 |
6170-0470 |
6310-0470 |
6420-0470 |
| 5.5 |
2370-0550 |
6010-0550 |
6090-0550 |
6100-0550 |
6130-0550 |
6150-0550 |
6170-0550 |
6310-0550 |
6420-0550 |
| 7.0 |
2370-0700 |
6010-0700 |
6090-0700 |
6100-0700 |
6130-0700 |
6150-0700 |
6170-0700 |
6310-0700 |
6420-0700 |
| 9.0 |
2370-0900 |
6010-0900 |
6090-0900 |
6100-0900 |
6130-0900 |
6150-0950 |
6170-0900 |
6310-0900 |
6420-0900 |
| 11.0 |
2370-1100 |
6010-1100 |
6090-1100 |
6100-1100 |
6130-1100 |
6150-1100 |
6170-1100 |
6310-1100 |
6420-1100 |
| 12.5 |
2370-1250 |
6010-1250 |
6090-1250 |
6100-1250 |
6130-1250 |
6150-1250 |
6170-1250 |
6310-1250 |
6420-1250 |
| 15.0 |
2370-1500 |
6010-1500 |
6090-1500 |
6100-1500 |
6130-1500 |
6150-1500 |
6170-1500 |
6310-1500 |
6420-1500 |
| 18.5 |
2370-1850 |
6010-1850 |
6090-1850 |
6100-1850 |
6130-1850 |
6150-1850 |
6170-1850 |
6310-1850 |
6420-1850 |
| 20.5 |
2370-2050 |
6010-2050 |
6090-2050 |
6100-2050 |
6130-2050 |
6150-2050 |
6170-2050 |
6310-2050 |
6420-2050 |
| 24.0 |
2370-2400 |
6010-2400 |
6090-2400 |
6100-2400 |
6130-2400 |
6150-2400 |
6170-2400 |
6310-2400 |
6420-2400 |
| 27.0 |
2370-2700 |
6010-2700 |
6090-2700 |
6100-2700 |
6130-2700 |
6150-2700 |
6170-2700 |
6310-2700 |
6420-2700 |
| 32.0 |
2370-3200 |
6010-3200 |
6090-3200 |
6100-3200 |
6130-3200 |
6150-3200 |
6170-3200 |
6310-3200 |
6420-3200 |
| 38.5 |
2370-3850 |
6010-3850 |
6090-3850 |
6100-3850 |
6130-3850 |
6150-3850 |
6170-3850 |
6310-3850 |
6420-3850 |
| 40.0 |
2370-4000 |
6010-4000 |
6090-4000 |
6100-4000 |
6130-4000 |
6150-4000 |
6170-4000 |
6310-4000 |
6420-4000 |
| 45.0 |
2370-4500 |
6010-4500 |
6090-4500 |
6100-4500 |
6130-4500 |
6150-4500 |
6170-4500 |
6310-4500 |
6420-4500 |
| 50.0 |
2370-5000 |
6010-5000 |
6090-5000 |
6100-5000 |
6130-5000 |
6150-5000 |
6170-5000 |
6310-5000 |
6420-5000 |
| * All circle diameters are in centimeters |
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