Molded Elastomeric Diaphragms

Dia•com has capabilities to design and manufacture composite diaphragms made from ptfe/elastomeric materials. dia•com’s process bonds ptfe to rubber using teflon as thin as 0. 002" (0. 0508 mm) thick. Dia•com’s unique process and construction produce a diaphragm that is compatible with harsh environments without limiting the life and responsiveness of the diaphragm. For additional strength, fabric may be added to the teflon/elastomer composite.

Benefits Include:

• Excellent chemical resistance

• Temperature extremes (-450/400°f, -267/204°c)

• FDA approved materials

• Low permeation rate

• Low co-efficient of friction

Teflon® is a registered trademark of dupont corporation

Dia•Com has ca

pabilities to bond metal or plastics to diaphragms during the molding process. Mechanical bonding is generally the least expensive and simplest method to achieve. This process is accomplished by designing the insert with projections or holes. During the molding process the insert becomes totally or partially encapsulated by the elastomer creating a strong mechanical interlock. Figure 1 illustrates a mechanical bond.

Chemical or adhesive bonding utilizes a commercial adhesive applied to the non-elastomeric component. The component is then attached to the elastomer during or after vulcanization depending on the type of bond required and geometry of the diaphragm. Figure 2 illustrates an adhesive bond.

When designing the metal insert, it is recommended to avoid sharp projections extending into the elastomer or sharp corners at the junction line between the two materials.

Steel is the most prevalent insert material used, but brass, stainless steel, aluminum, and nylon are also used. Certain elastomers and insert materials can also develop a cohesive bond through molecular attraction. This is most commonly accomplished with the use of brass and sulfur-cured nitrile.

By bonding inserts to diaphragms, costly assembly operations can be reduced or eliminated. Additionally, rivet, screw or other fastening methods which might create leakpaths through the diaphragm would be eliminated with a bonded insert.

 

Fabric-reinforced diaphragms utilize a layer of an engineered fabric material as part of the diaphragm construction. This layer of fabric gives tremendous design flexibility. A very thin-walled diaphragm can withstand high pressures while remaining very flexible and responsive to minor pressure variations.

Fabrics made of polyester, nylon and silk are commonly used for most applications, with Nomex fabric used for those applications exposed to high-temperature. For those applications that require extremely high-strength, Dia•Com offers our unique Dia•Tuff fabric.

All types of elastomers, such as, nitrile, EPDM, fluorocarbon, neoprene, silicone, fluorosilicone, can be used in the fabric-reinforced diaphragms.
Fabric-Reinforced Diaphragms Offer:

• Positive Seal

• Low Spring Rate

• No Lubrication

• No Breakaway Force

• No Friction

• High Strength

• Functionality Over Wide Pressure Ranges

• Low Cost

• Simple Design

• Versatility

In very low-pressure applications, the strength seen in fabric-reinforced diaphragms may not be necessary. For these special applications, DIA com offers diaphragms made with a homogeneous, or all-rubber, construction. These diaphragms offer the same functional advantages seen in fabric reinforced diaphragms but they have the added economy of using the homogeneous construction. homogeneous construction is possible using all types of elastomers.

Dia•Com has introduced a new line of specialty industrial diaphragms composed of our new Fab•Air materials. Fab•Air is a composite elastomer material with a proprietary fiber dispersed throughout the elastomer. It is presently available in GFLT, EPDM, Silicone, Fluorosilicone and Nitrile. Fab•Air is typically used in low pressure applications to eliminate ballooning replacing all rubber diaphragms. It also can be used in conjunction with fabric reinforced diaphragms in extremely high pressure applications to give the diaphragm added strength and reduce the possibility of blow through.

FAB•AIR Diaphragms Offer:

• Resistance to ballooning in low pressure applications

• Excellent gasketing capabilities due to its low compression set

• Capability of being manufactured thin for sensitivity

• Superior strength and repeatability over homogeneous diaphragms

• Long stroke to bore ratio exceeding the typical 1:1 associated with fabric reinforced diaphragms