DIAPHRAGM CLASSES

DIAPHRAGM CLASSES
CLASS 3C

The Class 3C diaphragm has characteristics similar to the Class 3 except the convolution is molded in. The information concerning flange design described for Class 3 also applies to Class 3C diaphragms.

Since this diaphragm is made in the “as-installed” shape with a permanent convolution it does not require inversion at assembly. It has a small centering force which may tend to return the diaphragm to its “as-molded” or neutral plane position. Because no inversion is required, only a flat retainer plate is needed to retain the head of the diaphragm to the piston.

The stroke of the Class 3 C design is limited since deep molded convolutions are presently impractical to manufacture. It is recommended this design be used where differential pressures do not exceed 150 psi.

D .25 to .99 1.00 to 2.50 2.51 to 4.00 4.01 to 8.00 8.01 and up
K As required to yield design stroke (See standard size tables and Note 1 below.)
DC Tolerances on DC and DP are ± .010" per inch of diameter but the tolerance will be no less than ±.010" or greater than ±.060"
Dp
WH & WF .020 ± .003 .020 ± .004 .030 ± .004 .035 ± .005 .045 ± .007
WSW .015 ± .003
(Code “B”)
.017 ± .003 (Code “C”) .024 ± .004 (Code “D”) .035 ± .005 (Code “F”) .045 ± .007 (Code “H”)
A .025 Max. .025 Max. .035 Max. .040 Max. .056 Max.
B .025 Max. .025 Max. .035 Max. .040 Max. .056 Max.
F 1/32 R. 1/16 R. 3/32 R. 1/8 R. 1/8 R.
DF DC + 5/16" DC + 1/2" DC + 3/4" DC + 1" DC + 1"
WB .093 ± .003 .125 ± .003 .187 ± .003 .250 ± .003 .250 ± .004
HB .094 ± .004 .135 ± .004 .200 ± .005 .270 ± .006 .270 ± .008


NOTES: 
1. Height tolerance is ±.015"
2. This “V” rib is for diaphragm processing only and it may not appear on all diaphragms. It is not functional and need not be completely filled. Rib is normally on rubber side of diaphragm.
3. Two “V” ribs may be used on beads that are .25 or larger in width.
4. Number, size, spacing and location of “V” ribs may be modified to suit specific beads, or may be left off altogether.
5. Trim tolerances
Hole Diameter OD Trim
Diameter Tolerances
0-1.00" ±.010"
1.01-3.00" ±.015"
over 3.01" ±.020"
6. Dimensions and tolerances pertain to Bellofram Rolling Diaphragms as manufactured and not to dimensions and tolerances of mating parts.