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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual

Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual

Product catalog summary

The Rolling Diaphragm Concept
The Bellofram Rolling Diaphragm is a flexible seal designed to eliminate friction and leakage, ideal for high-pressure and temperature environments. It is constructed from a fabric layer impregnated with elastomer, providing high tensile strength and flexibility.

Operating Features & Benefits

Friction-Free: Eliminates sliding friction.
No Breakaway Friction: No resistance to start-up motion.
No Spring Rate: Consistent resistance throughout the stroke.
High Sensitivity: Responsive to small pressure changes.
Long Life: Durable construction ensures longevity.
Leak-Proof: Prevents blow-by leakage.
Versatile: Suitable for a wide range of pressures, temperatures, and fluids.
Low Hysteresis: Consistent positioning regardless of stroke direction.

Applications
Used in industries like automotive, aerospace, and medical, suitable for applications requiring high sensitivity and no leakage, such as pressure regulators and linear actuators.

Design and Manufacturing
Bellofram's facility in Newell, WV, is equipped for high-precision manufacturing, offering SPC documentation and ISO 9002 certification.

Important Notice
Recommendations are based on reliable tests, but Bellofram disclaims responsibility for product use beyond its control, emphasizing compliance with laws and patents.

Introduction
This document serves as a design manual for selecting and designing hardware for Bellofram Rolling Diaphragms, providing detailed specifications, procedures, and recommendations.

Diaphragm Specifications

Head Corner Radius: The blend radius between the head and sidewall.
Height (H and K): Measured from the bottom of the flange to the top of the head or convolution.
Height/Stroke Limits: Formulas provided for necessary height for a particular stroke.
Identification: Identified by a Bellofram ABC part number.

Design Considerations

Diaphragm Selection: Configurations like "Top Hat," "C" Style, and Involuted (IVD) are available.
Diaphragm Class: Classes determine flange and bead design.
Stroke Capability: Calculations for half-stroke and full-stroke capabilities.
Elastomer and Fabric Selection: Chosen based on application conditions.
Hardware Design: Includes considerations for diaphragm flange retention and cylinder design.

Class 4 Diaphragms

Description: Common design for economical hardware.
Pressure Sealing: Capable of sealing high pressures.
Flange Design: Flanges can be perforated and trimmed for high-pressure applications.

Dimensions and Tolerances
Detailed tables provide dimensions and tolerances for various configurations.

Conclusion
This manual provides comprehensive guidance for selecting and designing Bellofram Rolling Diaphragms.

Overview
Detailed specifications, procedures, and recommendations for various classes of Bellofram Rolling Diaphragms, including technical data, dimensions, tolerances, and installation guidelines.

Specifications
Lists detailed measurements for cylinder bore, piston diameter, height, sidewall thickness, and more.

Procedures
Installation procedures emphasize diaphragm inversion prior to installation for certain classes.

Standards and Tolerances
Tolerances for dimensions are provided with specific values for different size ranges.

Recommendations
Advises on using specific diaphragm designs where differential pressures do not exceed 150 psi.

Class Descriptions

Class 3C Diaphragms: Molded with a permanent convolution.
Class 1A Diaphragms: Features an 'O'-Ring type bead.
Class 1B Diaphragms: Utilizes a rectangular bead.
Involuted Diaphragms: Offers reduced hardware size and cost.

Key Data Tables
Includes tables with specific measurements for each diaphragm class.

Introduction
Provides detailed technical specifications and guidelines for the design and application of rolling diaphragms.

Specifications
Effective area of an IVD remains constant in a full 180º convolution.

Elastomer Data
Lists elastomers with properties, including air permeability ratings and temperature limits.

Fabric Performance Data
Working pressure capability influenced by fabric reinforcement's strength factor.

Hardware Design
Discusses various hardware designs, including curved lip retainer plates.

Diaphragm Flange Retention Methods
Describes methods for retaining diaphragm flanges.

Conclusion
Comprehensive guide for selecting and designing rolling diaphragms.

Specifications and Design Considerations
Discusses methods for attaching bonnets to cylinder housings.

Hardware Design - Class 1B
Relies on volumetric fill for sealing.

Diaphragm Trim and Perforation
Recommendations for designing perforations and trims.

Assembly and Attachment Methods
Describes forming diaphragm convolutions during assembly.

Pressure and Mechanical Considerations
Discusses effects of pressure reversal and surface coatings.

Designing for Increased Diaphragm Life
Factors for durability include piston configuration and pressure control.

Application Data and Assistance
Bellofram Engineering offers assistance in selecting and applying rolling diaphragms.

Introduction
Provides a detailed questionnaire and guidelines for specifying and ordering diaphragms.

Technical Specifications
Outlines necessary information for diaphragm specification.

Ordering Procedures
Advises on selecting standard sizes for cost savings and efficient delivery.

Diaphragm Design and Application Assistance
Bellofram offers design and application assistance.

Diaphragm Technologies
Describes various diaphragm technologies offered by Bellofram.

Catalog excerpts

Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-2

ORIGINATOR OF THE ROLLING DIAPHRAGM The Rolling Diaphragm Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Theory of Rolling Diaphragm Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3Typical Diaphragm Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3Rolling Diaphragm Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-3

IMPOR T ANT NOTICE Our recommendations, if any, for the use of this product are based on tests believed to be reliable. The greatest care is exercised in the selection of our raw mate-rials and in our manufacturing operations. However since the use of this product is beyond the control of the manufacturer, no guarantee or warranty, expressedor implied is made as to such use or effects incidental to such use, handling or possession or the results to be obtained, whether in accordance with the directionsor claimed so to be. The manufacturer expressly disclaims responsibility therefore. Furthermore,...

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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-4

ORIGINATOR OF THE ROLLING DIAPHRAGM The Bellofram Rolling Diaphragm > ✣ () is a tough, flexible seal with a unique configuration that permitsrelatively long piston strokes while completely eliminating sliding friction.Formed in the shape of a truncated cone, or top hat, the diaphragm is turned in on itself when installed so that,during the stroke, it rolls and unrolls alternately on piston skirt and cylinder wall. The rolling action is smooth and effortless, completely eliminating sliding contact and breakaway friction. With the outer flange clamped to the cylinder and the center fastened to...

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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-5

ORIGINATOR OF THE ROLLING DIAPHRAGM Bellofram Rolling Diaphragms are, in effect, pressure vessels having a variable volume and flexible moving side-walls. As in any other pressure vessel, their strength should be considered with respect to safety factors. Generally, they are designed with a large safety factor. This means the maximum safe working pressure will be a fraction of the pressure that could cause failure of the sidewall.The accompanying illustration, Fig. 3, illustrates the pressure reaction of the . Here it can be seen thatalmost the entire pressure load is supported by the piston...

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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-7

ORIGINATOR OF THE ROLLING DIAPHRAGM > Piston DC (CylinderBore) C (Convolutionwidth) DP (PistonO.D.)PistonCorner Radius (RP) CylinderElastomerSide Diaphragmas Molded Fabric Side Cylinder Corner Radius(RL) DiaphragmAfter Inversion for Installation orPreconvolutedDiaphragm > WHWSWF Rad.WF WSW F Rad. F Rad. HE Rad. K WF WH DF DF

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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-8

ORIGINATOR OF THE ROLLING DIAPHRAGM The purpose of this Design Manual is to guide you in the selection of the proper Bellofram Rolling Diaphragm() for your application as well as to describe the applicable hardware design criteria.To efficiently select a diaphragm and to design hardware, it is advisable that decisions be made in logicalsequence. The information in this Manual, presented in detail on the following pages and briefly below, is in such sequence. The first step is to complete the Design Parameter Sheet*. This will provide basic information that will aid you in making selections from...

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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-9

ORIGINATOR OF THE ROLLING DIAPHRAGM > (note 4) DC .25 .99 1.00 ֖ 2.50 2.51 4.00 4.01 ֖ 8.00 8.01 and up H As required to yield design stroke (See standard size tables & NOTE3) DC Tolerances on DCand Dp are .010" per inch of diameter but the tolerance will be no less than ѱ.010"or greater than .060" Dp WH& WF .020 ѱ.005 .020 .005 .030 ѱ.005 .035 .005 .045 ѱ.007 WSW .015 .003(Code ѓB) .017 Ա.003(Code CӔ) .024 .004(Code ѓD) .035 Ա.005(Code FӔ) .045 .007(Code ѓH) E 3/32 R. 1/8 R 5/32 R 1/4 R 1/4 R F 1/32 R 1/16 R 3/32 R 1/8 R 1/8 R DF DC+ 3/4"See Note 4 DC+ 1"See Note 4 DC+ 1 > 1 ԢD > 2 "See Note...

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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-11

Cylinder Bore DC Piston DiameterDP Height H SidewallThickness Wsw Effective PressureArea Ae (in) Convolution C Maximum HalfStroke SA/SB Cylinder Bore DC Piston DiameterDP Height H SidewallThickness Wsw Effective PressureArea Ae (in) Convolution C Maximum HalfStroke SA/SB >

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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-13

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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-19

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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-23

ORIGINATOR OF THE ROLLING DIAPHRAGM Involuted Diaphragms may be made depending on design parameters. D > ESCRIPTION The patented* Bellofram Involuted Diaphragm (IVD) > TM represents a new concept in rolling diaphragm design.Developed initially to satisfy the needs of the automotive industry for low-cost hardware, small package size and lower assembly cost, the design offers significant advantages over convoluted diaphragms in many applications.Involuted diaphragms differ in both configuration and operation from the conventional designs. IVD diaphragmsidewalls drop almost straight down from the...

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Marsh Bellofram - Bellofram Rolling Diaphragm Design Manual-25

ORIGINATOR OF THE ROLLING DIAPHRAGM > Fabric normally used is: Code B, for all top hat sizes with: Code C, for all top hat sizes with: > DC 2 > 1 ڢD > 2 "(any height)or2 DC> 4"(any height)or2 > 1 ⁄ > 2 " < DC 4"H < DC /2 > 1 ⁄ > 2 " < DC 4"H > DC /2 Code P, for all preconvoluted sizes. > ABRIC SE Fabric Code Type Strength factor Duty A Polyester 17 General Purpose (Top Hat) B Polyester 28 General Purpose (Top Hat) C Polyester 47 Heavy Duty (Top Hat) P Polyester 32 General Purpose (CӔ Style) V Nomex 23 High Temperature L Polyester 44 Heavy Duty (Top Hat) W Polyester Knit 1.8 Light Duty 259 Nomex...

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