No.131 420mm dia. W/C/H 32mm Qualitative Filter Papers , Box 100

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 µm DOP)

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

(Coarse)

65

4

410

or 1450cv

No. 2

Retains medium crystalline precipitates, fast flow rate, smooth surface, normal hardness

125

0.26

80

8.0

8

5

(Medium)

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

(Med.-Fine)

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

(Coarse and gelatinous)

-

91

-