Flow Control Glossary

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Abaqus non-linear structural analysis (FEA):

Non-linear structure analysis FEA of both static and dynamic systems use specific material formulations that can predict part function.  Stress-Strain property measurements provide the details needed to improve the accuracy of the model simulation. 

Air or Water Test Machines

Functional performance curves are primarily produced using air or water.  The results produce a differential pressure versus flow curves on elastomeric check valves, as well as flow control products, using either air or water as the test media.  


The test machines are fully automated with computer controls are used almost non-stop in an effort to understand performance and improve quality.  These machines can test every valve Vernay produces, from the smallest duckbill valve (less than 0.003 SLPM air flow at 10 mbar) to the largest umberlla valve (greater than 200 SLPM air flow at 10 mbar).  Vernay's air test machines use a pc based data acquisition system to produce the complete differential pressure versus mass flow performance curve in an average time of 20 minutes.  The results are displayed on the screen real time and stored on a network at completion of test.  Capable of controlling differential pressures from 0.3 to 4,500 mbar, they measure pressure with an accuracy of 2% of reading over nearly the entire range, and measure flow from 0.01 cc/in to 150 L/min with 2% of reading accuracy above 1 cc/min.  The end results are a complete functional performance curve made from an increasing forward pressure ramp, a decreasing forward pressure ramp, and an increasing reverse pressure ramp.  Each pressure ramp provides several key performance indicators which help define the valves function.

CFDesign computational fluid dynamics (CFD) tools for coupling FEA with CFD

For applications where there are concerns regarding undesired flow circulations, cavitations and noise, precise pressure loss, and the degree of turbulence, CFD alongside FEA provides a more complete model.  In some cases it is desirable to couple the two solvers to provide a complete interactive solution.

Compression Molding

A "preform" of a rubber compound is placed between two halves of an open mold and the desired rubber part is formed by closing the mold around the preform under pressure.  This forces the preform to take on the shape of the cavity and forces out excess material (in the form of "flash").  This is the primary method of forming all molded rubber parts or rubber products.

Continuous Molded Rubber Strip

The continuous molding process is the result of a manufacturing process unique to Vernay.  This process allows for the production of rubber and rubber-to-metal strip in a range of widths and thicknesses and held to close tolerances.  The process offers the convenience of extrusion with the tolerances of molding.  We offer continuous rubber strip in both EPDM and silicone that are used in some of the most demanding applications in industries worldwide.  Strip width and thickness can be modified to provide the exact size to fit your cutting and assembly equipment, or we can provide individual pieces to suit your needs.

Direct Injection

The screw extruder fills the injection chamber and the mold is closed under clamp pressure.  The ram then comes forward, forcing the rubber through the runner system into the cavity, filling the part.  Runner systems can be "hot" or "cold", or a combination of both.

Elastomeric Compound:

An elastomer is any type of polymer that has rubber-like properties.  Unlike plastic materials, rubber in its raw state is not ready for use; it has to be mixed first with other ingredients. A heat treatment then transforms the compound into a useful rubber part, designed to meet specific functional requirements.


Reinforce the compound and allow for the adjustment of the mechanical properties of the rubber. 

Functional Testing:

Functional testing characterizes the entire performance envelope of the finished product where ever possible.  This is crucial in Verifying New Product Designs, Reducing Prototype Iterations and Developing Baseline Performance Curves

Injection Molding

A screw extruder feeds the material "rubber" directly into a pot/ram injection chamber.  This chamber injects the material, or rubber, through a series of flow channels, called a runner system directly into the mold cavity, or into a transfer pot and then into the cavities.  There are many configurations and variations possible.

Injection Compression

The rubber material is injected into a slightly open cavity, and then the mold is clamped shut.  For all rubber parts, waste is similar to compression molding.  De-molding can be easily automated. 

Injection Transfer (Hot or Cold)

The injection unit fills a pot unit with rubber.  The mold and pot are then clamped under pressure to transfer rubber from the pot, through sprues, into the cavities.  This doesn't require a complex runner system and allows for higher cavity density than straight injection. 

Insert Bonding:

Insert bonding ensures cohesive surface-to-surface bonding (chemically and/or mechanically), rigid reinforcement to the molded elastomer and consistent operation.  Elastomeric tips can reduce noise, resist impact, provide tighter tolerances and facilitate positive sealing even when foreign particles are present.  They also prevent abrasion and eliminate the leakage and wear of mating components. 

Insert bonded Product Types:

Insert bonded products include: needle valves and armatures, stator seals, plungers, momentum absorbers, laminated discs, poppets/sleeves, seal plates, filter screens, specialty shapes and bearings.

Insert Reinforced Products:

Similar to elastomer-to-insert bonded products; insert-reinforced products provide cohesive surface-to-surface bonding and rigid reinforcement to the molded elastomer. They maintain the shape and alignment of the elastomer while providing a tight seal and are wear resistant.

Miscellaneous Ingredients:

Such as blowing agents, pigments, retarders and odorants have specific purposes but are not necessarily required.   

Plasticizers and processing aids:

Soften and improve processing during mixing, extrusion, and molding of our precision rubber products. 

Polymer Materials:

Polymers are the most essential components of a rubber compound, determining the general chemical and mechanical properties of the final product.

Proprietary Software:

Proprietary software which quickly simulates common part families.  It automates such studies by coupling Abaqus with the MiniTAB design of experiments (DOE) tool into one application providing customers spreadsheets, animations, and recommendations.


Provide additional protection against the attack of heat and other environmental factors. 

Solid Edge CAD:

 Solid Edge CAD quickly develops parametric part models

Sigma 3D mold flow analysis

Full 3D physics modeling of rubber molding which includes green rubber flow properties, cross-linking, and simultaneous thermal analysis of the heaters, mold, cavities, and rubber to optimize the molding process.

Transfer Molding (Hot and Cold)

Rubber compound is forced (transferred) from a reservoir into a closed mold through a small opening (gate or sprue) to fill it, creating the desired shape.  This is ideal for molding rubber-to-rubber or rubber-to-plastic inserts and for small parts with intricate details.


Agents cross-link the polymer to form a network, which is the reason why the rubber can be stretched and still recovers effortlessly.