Critical Medical Applications

Medical Component Devices

Assemblies for Medical

Vernay meets the needs of medical device and diagnostic equipment manufacturers by offering a variety of elastomeric fluid control options that provide your device with accurate and repeatable performance. These products are ready to be designed into your application, providing cost-effective, safe and reliable fluid handling. Vernay also provides test data and specifications to support your device qualification process. We offer a comprehensive range of biocompatible Silicones or Vernay Polyisoprene formulations for your fluid, gas, and media-based applications. We also have experience using other component materials such as:

• PEEK
• Polycarbonate
• Polysulfone
• ABS
• PVC
• Stainless steel
• Titanium
• Brass

Our capabilities also include designing, assembling, and testing finished sub-assemblies, including Class VI thermoplastic housings with integral biocompatible elastomeric valves such as those found in:

• Mini-TITO® Check Valve Assembly
• Supravalve® Check Valve Assembly

Bi-Directional Valves / Seals

• Dome shaped all-rubber valves open more easily in one direction than the other
• Slit at top of dome opens more easily when pressure is applied on the dome inside
• Opening in the reverse direction (pressure outside dome) requires buckling
• Can be engineered with two specific opening pressures based on shape/thickness
• Flow is always more restricted than with duckbill and umbrella valves
• Valve is mounted by the flange the same way a duckbill is mounted
• Often used not as a valve but rather as a catheter seal (seals around a probe / pipe)

Combination Valves

An umbrella can be combined with a duckbill to provide a three-port valve which has an inlet, an outlet, and a port which articulates with a common variable volume. This is a convenient way to make a pump. When the volume increases, fluid is drawn in through one valve (usually the umbrella) and then when the volume decreases, fluid is pushed out through the second valve (usually the duckbill). The umbrella can have an opening (or cracking) pressure which is chosen to prevent flow due to head height at the inlet.

Diaphragms

Vernay Diaphragms are engineered to provide quality performance at specific pressures, even under the most demanding environments. Because of their unique design, Vernay Diaphragms perform complex tasks in mechanical, fluid, and gaseous applications easily and economically. They provide optimum sensitivity and the strength to withstand significant pressure change. Vernay specializes in convoluted diaphragms, thin wall diaphragm, rolling diaphragms, general diaphragms, servo action diaphragms, and inserted diaphragms.

• Used to convert pressure to force/stroke or vice versa
• Provides a fluid (gas or liquid) seal between the two sides
• May have a rigid center section to give more “piston-like” action
• Total stroke needed impacts the design of the convolute
• Material may be critical for chemical attack, gas permeation, and life

Duckbill Check Valves

Vernay Duckbill Check Valves are precision-molded, one-piece elastomeric valves that provide reliable backflow prevention at low-pressure differentials. Our duckbill check valves allow free flow with positive differential pressure. With negative differential pressure, backflow is checked. Pressure drop across the valve is a feature unique to Duckbill check valves. They can be designed to operate in a few millimeters (inches) of water to several hundred kPa (psi), depending on valve size, geometry, and compound characteristics. Vernay Duckbill check valves are also designed to start functioning at specific opening and closing pressure ranges, depending on your specifications.

• Normally open one-way check valves
• Prevent backflow leakage when minimal backpressure is applied
• Installed easily into hole and sealed by compressing flange

Flow Controls

• Flexible rubber component sits in a pocket in the flow path
• As pressure increases, the rubber deforms to reduce the center hole size
• Rubber material properties and shape result in constant rate of flow
• Typical useful pressure range is 20 to 120 psi (138 to 827 kPa)
• Retaining ring should not apply axial force but only prevent misorientation
• Each control is designed to work with a specific pocket shape
• New center post design for superior performance
• Some very low rate controls (drippers) use a flat stock design

Molded Strip / Gaskets

Vernay’s continuous molded strip is the result of a proprietary manufacturing process. This process allows for the production of rubber and rubber-to-metal strip in a range of widths and thickness, all held to very precise and close tolerances. Our molded strip is used in some of the most demanding applications in the world. Using a stable and repeatable process, this method yields close tolerance strip in continuous lengths for optimum performance.

• Continuous molded strip up to 4.7” wide
• High precision thickness tolerances
• Supplied in a reel form or punched into custom gasket shapes

Umbrella Check Valves

Vernay Umbrella Check Valves are designed to open and close at a range of predetermined pressures and can be developed for high or low opening pressures. Pressure drop across the valve is controlled by the modulus of material, effective flow area, the amount of pre-load on the sealing edge, and the thickness of the umbrella skirt section. Vernay’s lightweight Umbrella check valves allow flow in one direction and check flow in the opposite direction. They are self-actuating, easy to assemble, and unaffected by orientation, so performance is the same even if the valve is mounted upside down.

• Normally closed one-way check valve
• Open in pre-determined pressure range
• Installed into flat seat with flow holes underneath

V-Balls

Vernay offers ground elastomeric balls with excellent surface quality and good sphericity without parting lines. V-Ball® elastomeric balls are small, versatile, resilient spheres used in applications such as simple check valve components with spring support, indicators, or as a shuttling valve. V-balls® provide the flexibility to enhance sealing, are lightweight, and can be designed for high abrasion resistance. They are compliant enough for low-pressure sealing applications and resilient enough to withstand severe vibration and impact. V-Balls® are non-magnetic, corrosion resistant, and economical; requiring no lubrication during use, and are perfect for high-speed assembly because no orientation is required. Vernay’s solid V-Ball® elastomeric spheres are finished in a proprietary manufacturing process that provides improved diameter and sphericity as well as smoother, more uniform surfaces. V-Ball® products are finished to maintain such close tolerances that flash lines are eliminated.

• High pressure and high frequency cycling
• Medical and food grade materials
• Silicone materials as low as 30 durometer
• Variety of colors for indicator valves
• Electrically conductive materials
• Variety of specific gravities