Pure-Flo®

22 DIAPHRAGM SELECTION
Pure-Flo ® FDA Compliant Diaphragms shown clockwise:
Buna N Grade P, White Butyl Grade WB, Black Butyl Grade
B, Pure Gum Rubber Grade A, EPDM Grade H, PTFE Grade
R-2.
Pure-Flo Solutions Group offers a wide variety of
diaphragms which means more versatility at all application
levels. The chart at the bottom lists diaphragms
compliant with FDA Code of Federal Regulations Title
21. All elastomer diaphragms comply with Section
177.2600 of the Code. The PTFE Diaphragm complies
with Section 177.1550 of the Code.
Pure-Flo Solution Group’s two-piece PTFE Diaphragms
have proven through years of outstanding service to
be the best design available. The two-piece construction
eliminates the delamination problems inherent in
competitive “PTFE faced” diaphragms.
DIAPHRAGM COMPLIANCE
DIAPHRAGM FDA USDA 3A
Soft Rubber � �
Black Butyl � �
EPDM(16) �
EPDM(H) � � � **
Buna N � � � **
White Butyl � �
R-2 PTFE � � � *
TM PTFE �
* Class I applications
** Class III applications
Floating Tube Nut:
The floating tube nut design assures that downward
closing forces will be absorbed by the elastomer backing
cushion and evenly distributed across the closing
surface (weir) in the valve body. The result is reduced
cold flow, drop tight closure and longer diaphragm
life. This reduces point loading of the diaphragm and
eliminates stud pull out.
R-2 PTFE Diaphragm Assembly:
Available in sizes 1/4"–10" (DN 8–250).
Maximum temperature rating of 350°F (176°C).
TM PTFE Diaphragm Assembly:
Available in sizes 1/4"–6" (DN 8–150).
Maximum temperature rating of 350°F (176°C).
DIAPHRAGM TYPE SIZE TEMPERATURE
GRADE MATERIAL INCH DN °F °C
A Pure Gum Rubber 3/4–4 20–100 -20–160 -29–71
B Black Butyl Rubber 1/2–12 15–300 -20–250 -29–121
16 EPDM 1/4–4 8–100 -30–300 -34–149
H EPDM 1/4–6 8–100 -30–300 -34–149
P Buna N 1/2–12 15–300 10–180 -12–82
TM PTFE 1/4–6 8–150 -30–350 -34–176
R-2 PTFE 1/4–10 8–250 -30–350 -34–176
WB White Butyl Rubber 1/2–8 15–200 0–225 -18–107