Diaphragm Presentation

2. History of the Diaphragm Seal
 Concept of the diaphragm goes
back centuries
 Leather diaphragms were used in
pumps in ancient times
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3. History of the Diaphragm Seal
 Fabric reinforced elastomeric diaphragms were
developed in the early 20th century
 Long stroke rolling diaphragms were developed
in the late 1940’s
– Fabric preforming
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4. RPP Corporation History
Lynn
Boston
 Established in 1963 in Lynn, Massachusetts
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5. Boston
Lawrence
RPP Corporation History
 Focused in industrial markets primarily process
control and water management
 Moved to 55,000 square foot facility in Lawrence,
Massachusetts
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6. RPP Corporation History
 Established sales and distribution facility
in Kehl-Kork, Germany in 2000
 Employ about 130 people in both facilities
Berlin
Kehl-Kork
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7. RPP Corporation History
 Material development
 Diaphragm development
 Performance analysis
Product Development Capabilities
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8. Diaphragm Application Requirements
 Conversion of pressure to force
Seal Requirements
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9. O-Ring Function

10. Rolling Diaphragm Function

11. Diaphragm Application Requirements
 Sensitivity to pressure differentials
 No breakaway friction
 Zero leakage
Application Requirements
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12. Design Parameters to Meet
Application Requirements
Effective Area
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13. Design Parameters to Meet
Application Requirements
Stroke
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14. Design Parameters to Meet
Application Requirements
 Economical hardware design
Hardware Design Requirements
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15. Design Parameters to Meet
Application Requirements
Pressure Capability
Convolution
Width
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16. Design Parameters to Meet
Application Requirements
Temperature Capability
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17. Design Parameters to Meet
Application Requirements
Operating Media Compatibility
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18. Design Parameters to Meet
Application Requirements
Cycle Life Requirement
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19. Typical Applications
Process Control Valves
Input
Output
Process
Process
Controller
Feedback Signal
Signal Pressure
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20. Typical Applications
Pressure Regulators
Input
Output
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21. Typical Applications
Irrigation Valves
Input
Output
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22. Typical Applications
Web Tensioning
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23. Conversion of Application Requirements
to Diaphragm Requirements
 Effective Area = Diameter
Diaphragm Geometry
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24. Conversion of Application Requirements
to Diaphragm Requirements
 Stroke = Height
Diaphragm Geometry
RP
1.56 Convolution
Width
RF
1/2 Stroke
Convolution Width
2
RP / RF
1/2 Stroke
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25. Conversion of Application Requirements
to Diaphragm Requirements
 Hardware Design = Flange Design
Diaphragm Geometry
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26. Conversion of Application Requirements
to Diaphragm Requirements
 Pressure Capability = Fabric Specifications
Diaphragm Materials
Convolution
Width
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27. Conversion of Application Requirements
to Diaphragm Requirements
 Temperature Capability =
Fabric and Elastomer Specifications
Diaphragm Materials
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28. Conversion of Application Requirements
to Diaphragm Requirements
 Operating Media = Elastomer Specifications
Diaphragm Materials
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29. Conversion of Application Requirements
to Diaphragm Requirements
 Cycle Life Requirement = Fabric to Elastomer Adhesion
Diaphragm Quality Criteria
Fabric
Elastomer
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30. Conversion of Application Requirements
to Diaphragm Requirements
 Flexibility = Thickness and Tolerances
Diaphragm Quality Criteria
Molded
Dimension ± 2%
Molded
Dimension ± 2%
Processing
Dimension
± 30%
Die-Cut Dimension ± 0.5%
Processing
Dimension
± 15% Processing
Dimension ± 4%
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31. Conversion of Diaphragm Requirements
to Diaphragm Design
 Height to diameter ratio
Manufacturing Considerations
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32. Conversion of Diaphragm Requirements
to Diaphragm Design
 Material processing limitations
Manufacturing Considerations
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33. Conversion of Diaphragm Requirements
to Diaphragm Design
 Flange beads
Manufacturing Considerations
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34. Conversion of Diaphragm Requirements
to Diaphragm Design
 Rolling (top hat)
Diaphragm Style
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35. Conversion of Diaphragm Requirements
to Diaphragm Design
 Pre-convoluted
Diaphragm Style
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36. Conversion of Diaphragm Requirements
to Diaphragm Design
 Offset-convoluted
Diaphragm Style
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37. Conversion of Diaphragm Requirements
to Diaphragm Design
 Dished
Diaphragm Style
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38. Conversion of Diaphragm Requirements
to Diaphragm Design
 Single-coated
Diaphragm Construction
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39. Conversion of Diaphragm Requirements
to Diaphragm Design
 Double-coated
Diaphragm Construction
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40. Conversion of Diaphragm Requirements
to Diaphragm Design
 Bleed-thru
Diaphragm Visual Quality Criteria
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41. Conversion of Diaphragm Requirements
to Diaphragm Design
 Strike-thru
Diaphragm Visual Quality Criteria
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42. Conversion of Diaphragm Requirements
to Diaphragm Design
 Fabric impression
Diaphragm Visual Quality Criteria
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43. Conversion of Diaphragm Requirements
to Diaphragm Design
 Voids and non-fills
Diaphragm Visual Quality Criteria
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44. Conversion of Diaphragm Requirements
to Diaphragm Design
 Adhesion
Diaphragm Visual Quality Criteria
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45. 45
Validation of Diaphragm Design
to Application Requirements
 Diameter = Effective Area
– Piston Diameter
– Cylinder Bore Diameter
– Effective Diameter

46. Validation of Diaphragm Design
to Application Requirements
 Height = Stroke Requirement
– Overall Height / Piston Diameter
– Convolution Height / Convolution Width
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47. Validation of Diaphragm Design
to Application Requirements
 Materials = Pressure, Temperature
and Media Requirements
– Elastomer Selection / Temperature and Media
– Fabric Selection / Working Pressure and Media
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48. Validation of Diaphragm Design
to Application Requirements
 Quality = Performance Requirements
– Fabric to Elastomer Integrity
– Visual Quality Criteria
– Dimensions
– Materials
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49. RPP CORPORATION
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