Piston and Standard Convolution Width Dimensions
Piston and Standard Convolution Width Dimensions

Diaphragm Cylinder
Diameter
(Inches)		 Diaphragm Cylinder
Diameter
(mm)		 Piston Skirt Length Piston Radius
(Inches)		 Piston Radius
(mm)		 Standard
Convolution Width
(Inches)		 Standard
Convolution Width
(mm)

.37 to .99
9 to 25
Height + Half-Stroke
2

.0312
.080
.0625
1.59

1.00 to 2.50
25 to 64
Height + Half-Stroke
2

.0625
1.59
.0937
2.38

2.51 to 4.00
64 to 102
Height + Half-Stroke
2

.0937
2.38
.1562
3.97

4.01 to 8.00
102 to 205
Height + Half-Stroke
2

.1280
3.18
.2500
6.35

Piston Cap Dimensions
Piston Cap Dimensions Figure 1 Piston Cap Dimensions Figure 2

Diaphragm Cylinder
Diameter
(Inches)		 Diaphragm Cylinder
Diameter
(mm)		 1

 2
(Inches)		 2
(mm)		 3
(Inches)		 3
(mm)		 4
(Inches)		 4
(mm)		 5
(Inches)		 5
(mm)		 6
(Inches)		 6
(mm)

.37 to .99
9 to 25
Piston + 2
(Diaphragm Thickness)
Not
Required
1.59
Not
Required
.008
Not
Required
0.20
Not
Required
.125
.0625
3.18

1.00 to 2.50
25 to 64
Piston + 2
(Diaphragm Thickness)
.15 x Piston Thickness
3.81 x Piston Thickness
.010
0.250
.094
2.39
.012
0.310
.1870
4.75

2.51 to 4.00
64 to 102
Piston + 2
(Diaphragm Thickness)
.15 x Piston Thickness
3.81 x Piston Thickness
.015
0.380
.109
2.78
.015
0.380
.2180
5.54

4.01 to 8.000
102 to 205
Piston + 2
(Diaphragm Thickness)
.15 x Piston Thickness
3.81 x Piston Thickness
.015
0.380
.125
3.18
.015
0.380
.2500
6.35

Bonnet Dimensions
Bonnet Dimensions Figure 1 Bonnet Dimensions Figure 2

Maximum Diameter
 Length
 Maximum Radius

Piston Diameter + 4
(Diaphragm Gauge)
Diaphragm
Upstroke
Convolution Width
2

Cylinder Dimensions
Diaphragm Cylinder
Diameter
(Inches)		 Diaphragm Cylinder
Diameter
(mm)		 Length Radius
(Inches)		 Radius
(mm)

.25 to .99
6 to 25
Downstroke +
Piston Skirt
.031
.079

1.00 to 2.50
25 to 64
Downstroke +
Piston Skirt
.063
1.600

2.51 to 4.00
64 to 102
Downstroke +
Piston Skirt
.094
2.390

4.01 and up
102 and up
Downstroke +
Piston Skirt
.125
3.180

Flange Retention Methods for Type F and FC Diaphragms
Swaged Lip—Lending itself to high volume/low cost, the swaged lip resembles the crimp ring in design except that the lip is an integral part of the cylinder or bonnet. Lip should be flexible and thin to insure proper flange retention.
 Swaged Lip

Crimped Ring—This method lends itself to high volume and low cost manufacture. It utilizes a separate metal crimp ring and is assembled to the unit with special crimping tools. These crimp rings are made of thin, ductile materials so that the force required to form the lip will not overcompress the diaphragm flange area.
 Crimped Ring

Flange Retention Methods for Type D and DC Diaphragms
Pivoted Rocking Bracket—This method provides quick assembly and disassembly. The pivoted rocking bracket is attached to the housing flange, and the central jam screw secures the bonnet against the mating flange.
 Pivoted Rocking Bracket

Ring Clamp—“V” style clamp rings can be disassembled quickly by removing a clamp lever. A retainer plate is removed by turning it 90 degrees where two “wings” and a retaining screw drop into a keyhole.
 Ring Clamp

Beveled Edge Retainer Plate—Eliminates the need for flange bolts as a beveled edge ring is snapped into a groove in the extension of the cylinder housing flange. This loads the bonnet assembly onto the mating bead, generally producing low clamping forces.
 Beveled Edge Retainer Plate

Flange Retention Methods for Type O and OA Diaphragms
Crimped Ring—Used in high volume, low cost applications, this method eliminates typical flange construction and flange bolts.
 Crimped Ring

Bezel Ring—This common method provides minimum clearance of the housing outside diameter. Male threads are machined on the cast bonnet to utilize drawn sheet metal cylinder housings, reducing costs.
 Bezel Ring

Grooved Bonnet—This method requires a sufficient number of circumferential clamp bolts so distortion does not occur between flange bolts. It is advisable to make provisions for the bead groove in the cast or molded bonnet.
 Grooved Bonnet