Major diaphragm technologies and EFFBE products

Flat diaphragms

These diaphragms are used for very short stroke and are obtained by cutting flat materials: diaphragm cloth and/or elastomer sheets.

Definition

Design

The following basic rules must be observed to avoid excessive stress and the formation of folds in the diaphragm:

• The outside and centre distances of the diaphragm fixing holes must be increased by the correction coefficient K = 0.02 DG in relation to the dimensions of the appliance.
• The diaphragm must be re-tensioned during assembly so that the fixing holes and the outside of the diaphragm match the dimensions of the device.
• The flat diaphragm must also be able to reach the extreme working positions required without straining.

As a result, in relation to the internal diameter of the device, the maximum flat diaphragm stroke is low: up to 6% for regulation and up to 10% for other applications. Within these operating ranges, subsidence remains free of radial folds.

EXAMPLES OF FLAT DIAPHRAGMS

Convoluted diaphragms

EFFBE manufactures these diaphragms by vulcanising them on a press under the influence of pressure and temperature.

Definition

Design

We start with the following materials:

• Reciflex® diaphragms made from coated fabric. In this case, the textile will be perfectly centred, particularly in the radius and convolution. This technology does not allow the integration of a sealing bead.
• Elastomer with textile reinforcement either with textile on one side (Lay-up diaphragm) or with centred textile (Lay-in).
• 100% elastomer or elastomer with integrated short fibres.

This manufacturing process, apart from the specific case of Reciflex®, allows all appropriate shapes to be produced, and in particular sealing and centring beads integrated into the diaphragm. Moulding depth is relatively limited due to the thermoformability of the textures used. Diaphragms with texture on one side should only be subjected to pressure and the medium on the side without texture. Textureless shaped diaphragms have the advantage of great flexibility. They can only be used for small pressure differential. EFFBE offers optimum sizing by calculating all the above dimensions in order to meet operating and service life objectives.

EXAMPLES OF CONVOLUTION DIAPHRAGMS

Dish shaped diaphragms

Definition

Design

These diaphragms are used for medium stroke. EFFBE specifically suggests them for operating controls, actuators and pumps. They are mainly made from coated fabric (Reciflex®). They can also be moulded with the insertion of a lay-in or lay-up fabric.

EXAMPLES OF DISH-SHAPED DIAPHRAGMS

Rolling diaphragms

Definition

Design

These diaphragms are used for larger stroke . They are particularly recommended by EFFBE for control functions that can only be pressed towards the inside of the moulding. They require support on the contours of the housing and piston.

EFFBE offers optimum sizing by calculating all the above dimensions in order to meet operating and service life objectives.

EXAMPLES OF ROLLING DIAPHRAGMS

U-shaped diaphragms

EXAMPLES OF U-SHAPED DIAPHRAGM

Elastomer-based technical parts

For the manufacture of specific technical parts, EFFBE provides elastomer-based solutions that meet the requirements of its customers’ specifications. EFFBE’s experts can help with very specific design requests or queries about non-standard materials. In this case, EFFBE’s R&D team will develop materials formulated for perfect chemical resistance or excellent response to extreme temperatures.

EXAMPLES OF TECHNICAL PARTS

Diaphragms with insert

The perfect bond between the insert and the elastomer determines the lifespan of the whole assembly. EFFBE’s expertise lies in its perfect mastery of the processes and materials that ensure the bond between the elastomer and the insert.

If required, EFFBE will propose different types of inserts that can be used: metal, film, plastic, cardboard, paper, etc.

EXAMPLES OF DIAPHRAGM WITH INSERT

Pre-assembled diaphragms

EFFBE has a wealth of experience & expertise in the field of industrial applications and offers customers complementary production of complete sub-assemblies. This is why, in addition to designing and manufacturing diaphragms, EFFBE has the capacity to develop, model and produce plates, covers and cups which are then assembled with the diaphragms. With these specific sub-assemblies, EFFBE provides its customers with a value-added service. It enables them to reduce the number of suppliers, and to be faster, more efficient and more cost-effective by optimising costs and quality through the “Design to Cost” function.

EXAMPLES OF PRE-ASSEMBLED DIAPHRAGMS