�ǳ�web Knowledgebase - Isolation

Basic fluid mixing system designs involve connecting individual valves using fittings and tubing to create the required flow paths. This can be improved upon with manifold mounted valves, which reduce the number of possible leak points by reducing the number of required fittings while still allowing for fairly complex flow paths. However, this is often not ideal for more demanding applications requiring extremely low leak rates and less internal volume. In these situations, gradient valves may provide a more optimal solution.

What is a gradient valve?

A gradient valve consists of multiple 2-way valves integrated into a manifold with a common flow path. This allows for the function of one common input with multiple, independently controlled outputs—or alternatively, multiple inputs with a single common output. Gradient valves enable easy mixing or selecting from multiple sources, and further reduce the possible leak points from the fittings and tubing used in traditional systems.

The Unique Benefits of PTFE Gradient Valves

�ǳ�web's NIV series multi-channel gradient valves are specially designed for mixing and blending corrosive fluids such as those in applications involving volatile reagents, harsh cleaning agents, or other aggressive media. Multiple inlet flow paths are connected to a single outlet flow path, with each inlet having its own embedded isolation valve. Each NIV series isolation valve features a unique one-piece valve stem that functions as a sealing membrane, opening and closing the flow path while also supporting and centralizing the poppet in the seating area. This multifunctional diaphragm/poppet results in a simplified design that provides exceptionally long life and minimal dead volume. Unlike other isolation valves, all wetted areas of the �ǳ�web NIV series valves are precision-machined from PTFE—including the diaphragm—resulting in a highly inert flow path with no elastomers.

The flow path design, in combination with the NIV series valves' fast response times, allow for quick, easy mixing or selecting from up to six sources. The valves are also bidirectional, providing the added benefit that a single cleaning reagent can be flowed backward through the system from the outlet port in order to easily clean the entire mixing system.

Comparison of Individual, Manifold, and Gradient Valve Systems

Multi-Channel Gradient Isolation Valve Applications

Many types of applications require mixing and blending of different types of media. However, certain types of applications can especially benefit from the exceptionally low internal volume and inert flow path of the all-PTFE NIV series gradient valves. In particular, medical applications that involve the processing or testing of blood or other bodily fluids can benefit from the use of these multi-channel gradient isolation valves. After the fluid has been processed, different reagents may easily be flushed through the gradient valve to clean the system before the next use, and each inlet valve allows a different reagent to be flushed through the system.

Two major challenges often faced when mixing or blending in these types of applications include compatibility with the reagent and avoiding contamination. However, with its all-PTFE design, the NIV series provides an optimal solution with its highly inert flow path. An additional issue that often arises is the added cost that can be incurred due to unnecessary waste of expensive reagents. By minimizing the volume of flow paths, the amount of reagent required between tests is reduced, which in turn reduces waste and lowers operation costs.

When highly corrosive chemicals are used, multi-channel gradient valves such as the NIV series can be an ideal choice for applications which require the manifold capability as well as a low leak rate and small internal volume. One such application is the manufacture of microchip wafers using chemical etching. Due to the extreme volatility of the etching fluid, most gradient valves react poorly with the media and are not recommended. However, the chemical compatibility of PTFE makes the NIV series an ideal solution. An overall reduction in the total internal volume provides an added benefit as well, with less waste of costly chemicals.

There are many different ways to mix and blend fluids, each with different benefits and drawbacks. Multi-channel gradient valves are often a good solution for applications which require lower leak rates, less internal volume, or a smaller footprint. For demanding applications, �ǳ�web's NIV series gradient isolation valves provide all of these benefits in addition to a highly inert all-PTFE flow path for added chemical compatibility. However, ultimately, your specific application will determine which solution is right for you. �ǳ�web offers a wide range of products which can easily be adapted to better suit your needs. If you have any questions or need assistance, please contact �ǳ�web or your local �ǳ�web distributor.

By �ǳ�web

Precision Control for Liquid Extraction Applications

Rachel Desenberg — Tue, 29 Jan 2019 19:34:43 +0000

Category:

Applications

The field of liquid extraction presents unique challenges. While the separation of substances can be performed with a variety of different methods, these processes typically require precise control of multiple fluids within a single application. This can be complex, but �ǳ�web provides a simple solution.

Problem:

Selecting Between Multiple Solvents for Liquid Extraction

An OEM specializing in solvent extraction needed to select between multiple solvents as part of their unique vacuum distillation process. Due to the media being used, compatibility with a low leak solution was crucial to performance. The existing solution was cumbersome, involving three separate valves per line—fluid isolation valves, vacuum valves, and air piloted valves.

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Solution:

PTFE Mixing Valves Control Multiple Fluids

Laboratory productivity is a growing market where �ǳ�web delivers great value. In the field of liquid extraction, the separation of substances out of a sample can be performed with a variety of different methods. In this case, �ǳ�web's NIV series valves provided the perfect solution to select between the four different solvents required by the OEM's process. The PTFE valves provide inert and precise sealing for the fluid side, holding a tight leak rate as samples are passed from 50 kpa vacuum to 30 psig using nitrogen while the sample is injected to a heated extraction cell in its final stage. This solution eliminated the need for three separate valves per line, but �ǳ�web engineers were also able to further minimize the size—and reduce overall cost for the customer—by using a custom PTFE manifold.

Related Content

Video: Media Isolation Valves for Medical & Laboratory Instrumentation
Video: The Challenges of Working with PTFE - Design World Interview
Q&A with Miniature Pinch and Media Isolation Valve Expert

Related Products
NIV Series Solenoid-Operated PTFE Media Isolation Valves	NPV Series Solenoid-Operated Miniature Pinch Valves

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Video: Media Isolation Valves for Medical and Laboratory Instrumentation

Rachel Desenberg — Tue, 23 Aug 2016 15:08:32 +0000

Category:

Videos

Rob �ǳ�web, Vice President of Sales & Marketing, and Attila Kiss, NIV/NPV Product Manager, introduce �ǳ�web's new NIV Series of media isolation valves and discuss how this new series allows �ǳ�web to bring its valve expertise from the fluid power and control side of medical and laboratory applications to the control side of these devices for dispensing of media.

Filmed on location by Design World

Related Products:
NIV Series Solenoid-Operated PTFE Media Isolation Valves	NPV Series Solenoid-Operated Miniature Pinch Valves

Tags:

NIV

Isolation

Q&A with Miniature Pinch & Media Isolation Valve Expert

Rachel Desenberg — Fri, 29 Apr 2016 17:55:13 +0000

Category:

Advertising

Attila Kiss, Product Manager for �ǳ�web's new NPV and NIV lines, talks about his background and experience with miniature pinch and isolation valves, and what he sees for the future of isolation valves.

Attila Kiss
NIV/NPV Product Manager
�ǳ�web Instrument Laboratory

What is your role at �ǳ�web?

I am Product Manager of �ǳ�web's new NPV Series Pinch Valves and NIV Series Isolation Valves. I work with everyone involved—from manufacturing and engineering, to sales and marketing—to produce the lines and ensure the final products are of the highest quality.

What has led you to your current position?

I have been working with miniature pinch and isolation valves for more than 25 years. I began in a family machine shop at age 12 and continued through high school, learning to manufacture components that were used to manufacture miniature solenoid valves. This taught me a great deal about machining very tight tolerance parts.

After high school, I enlisted in the United States Marine Corps where I repaired heavy equipment and developed a quality control system. When my time in the military was over, I returned to the manufacturing industry where I ended up at a valve company—first machining components, then assembly, and finally setting up a quality control department at Biochem, a solenoid valve company. From there, I went on to become Production Manager at Neptune Research, a pinch and isolation valve company. I spent more than 20 years there managing all aspects of their miniature pinch and isolation valve lines, including manufacturing, design, marketing and sales.

What part of your job do you find most satisfying and/or what do you like about working in this industry?

The most satisfying part is developing a product that could potentially save lives. I enjoy the travel, working with customers and other companies to custom design products specific to their needs. The challenge of developing new products and resolving issues with existing ones is very satisfying. Also, being able to share my machining knowledge on the manufacturing side makes new processes easier. I have always enjoyed building, tinkering, machining and producing an end product.

What makes miniature pinch and isolation valves such a great fit for �ǳ�web?

Many �ǳ�web miniature pneumatic products are already in use in the same machines and equipment that use pinch and isolation valves. It's a natural fit for �ǳ�web to provide the isolated side of applications with the same quality and reputation they have in pneumatic components.

What types of applications do you see for these valves?

�ǳ�web pinch and isolation valves can be used in many different applications where precise dosing or dispensing is a must, such as DNA synthesizers, HPLC equipment, gas chromatographs, blood analyzers and dental equipment. They can be used with liquids or gases, and are ideal for a variety of laboratory diagnostic equipment uses, including applications that test air, water or biological materials. They are also well-suited for a variety of printing applications as well as multiple industrial applications where the control of a fluid is required.

What makes �ǳ�web's miniature pinch and isolation valves unique, or how would you compare them to similar valves already on the market?

The biggest difference is the �ǳ�web brand and the high quality, fast delivery and excellent service that come with it. In addition, you will find that compared to most other pinch and isolation valves, �ǳ�web's valves consume less power and feature a smaller, more compact design.

What are �ǳ�web's delivery/turnaround times like compared to others in the industry?

The NPV and NIV lines are currently on a lean system at �ǳ�web, meaning that most product will ship within 2 to 3 days once an order is processed. Many competitors can take weeks or more to deliver similar products. �ǳ�web has the capacity and systems to provide what customers need, when they need it.

What kind of testing is performed on the these valves?

Every �ǳ�web isolation valve is tested for flow and decay tested with helium in a clean room environment, and every �ǳ�web pinch valve is bubble leak-tested prior to packing and shipping. There is no batch testing. Every isolation and pinch valve is 100% individually inspected and tested.

Where do you see the future of isolation valves?

As the baby boomer generation comes of age, more diagnostic equipment will be required, thus putting an increased demand on the miniature solenoid valve industry. I believe we will see an increase in smaller, more portable machines manufactured in the future to help the medical industry diagnose and treat patients faster and more efficiently.

If you were stranded on a desert island, what three things would you take and why?

K-bar, matches and canteen. K-bar is my Marine Corps fighting knife for hunting and survival, matches to make fire much easier, and a canteen to save water.

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