In many industrial settings, air flow control is an issue that ought to be addressed. Pneumatic valve actuator products are a great way to control air flow and prevent leakages, which in turn will save time and money. For the latest news and information on pneumatic valve and pneumatic valve actuator innovation, browse the articles below.
Stepper-controlled pneumatic proportional valve
Cincinnati—Using a robust and powerful linear actuator, the high-flow stepper-controlled 2-way proportional valve features excellent performance and durability.
The bonded elastomeric seat achieves excellent sealing ensuring smooth opening and fine control at low flow for millions of cycles. Also features 2% hysteresis, excellent linearity (2.5% of full scale), and 2 ms reaction time. A flow range of 0 to 300 slpm is standard, however this product is highly modifiable for OEM applications including alternate body materials, flow profiles, cartridge styles, manifold mounting, etc.
This valve is suitable for applications including medical, analytical, and industrial automation requiring high resolution, high flow, and low hysteresis. In addition, the design allows for custom flow profiles when required.
Clippard also provides custom solutions for specific needs, including special configurations, manifolds, and pneumatic products.
Clippard Instrument Laboratory Inc.
Highly scalable valve manifold offers value, performance
Hauppauge, N.Y.—The Festo MPA-L valve manifold offers a mix of value and performance. It is scalable down to a single valve slice, so directional valves can be adapted to any application. This saves costs and reduces size.
The sub-base is made from a rugged polymer design that offers good corrosion resistance and light weight. The valves are electrically connected to an internal printed circuit board, which provides exact coil allocation with no wasted connections. A host of electric multi-pin connector options are available, as well as network interfaces to most common industrial and Ethernet protocols, via Festo’s CPX distributed I/O family.
All standard valve functions are available. These include 5/2, 5/3, and the cost/space saving dual 3/2 types. All valves use Festo’s patented cartridge principle, which has proved extremely durable, and offers outstanding flow rates. There are well over 10 million valves with this technology in service.
The manifold is suited for most pneumatic applications for discrete and process automation. The high flow rate to size ratio makes for universal applications from food and beverage packaging to semiconductor fabrication. The valve can run pressure and vacuum, with multiple zones. Key features include:
• Up to 32 valve locations, max flow rate to 360 Nl/min
• Inch and Metric ports for all markets
• Full range of pneumatic functions and accessories such as pressure regulators D-sub, IDC / Ribbon cable connectors, bus networks, and Ethernet connections
Proper design requires knowledge of valve types
By William Miller, Humphrey Products
Valves used in the medical device industry are designed with precise specifications so they are compatible with the requirements of the applications. Meanwhile, valves used in factory automation are designed to work within specific safety regulations. Every project has unique requirements and choosing the best pneumatic valve design for your application will provide optimum results.
While each design has its strengths and weakness to be considered, knowing your application’s requirements is essential. For example, the media of the application varies between industries. Compressed air and other gases can be extremely powerful—even fatal—so understanding how the valve will be used is important. Certain valve designs are compatible but limited by specific media. Some other factors that dictate the required valve are the external variables such as temperature range of the application, and purity of the air or media (moisture, contamination). Once you know the critical requirements for the application, the valve design can be chosen based on its specific features.
Poppet-design valves
Poppet-design valves use a rubber molded poppet wrapped around the stem that moves along the bore of the valve, creating a seal when the poppet is in its seat. One specific advantage to using a valve with this type of internal design is the compatibility with a variety of media other than compressed air. The unique feature that allows this compatibility is less lubrication sensitivity due to few sliding parts or (dynamic seals).
Another benefit to this poppet design is that the valves are more tolerant of minor air sediment or debris. They also have excellent exhaust capacity and are capable of high flow rates. The poppet design provides a faster response rate due to short stroke and can be mounted in several ways.
Poppet valves more readily lend themselves to 2-or 3-way configurations, although 4-way configurations can be achieved by using dual 3-way poppet sets in one valve body. Poppet valves are typically unbalanced designs, which use the air pressure as the primary force to return the valve to a given position. This concept provides assurances that the valve will return to the desired position, even if the return spring fails. Balanced poppet valves are used to reduce actuation force and achieve lower current consumption in solenoid valves. Balanced valves typically provide smaller overall physical size and produce greater flow capacity.
Applications in which this design are most commonly found are in the medical device and analytical instrumentation industries, where air purity is required (absence of dirty or wet media/air), the need for reliability is mandatory (could be saving lives), low leakage rate is critical, and gases other than compressed air will be used as a medium.
Diaphragm-poppet design valves
Diaphragm-poppet design valves expand the poppet valves’ design by the use of a diaphragm. Its outer webbing guides the poppet to its seat without using sliding seals. Diaphragm-poppet designs are usually unbalanced providing the same assurance of return to a given position as the poppet valve. The diaphragm increases durability especially with different or non-lubricated media.
A variety of durameter and diaphragm compounds make it simple to modify a valve based on the environmental or application requirements for operation. Also, expect extremely low leak rates due to strong sealing control. Diaphragm-poppet valves make 2-way or 3-way configurations available, as well as the possibility of 4-way valves, by using dual 3-way diaphragm poppet sets in one valve body. This valve’s durability and reliability make it a great candidate for applications such as critical life support devices (e.g. heart ventricular support assistance or pulmonary supply devices).
Its non-lubrication capability makes it appealing to be used with devices used for respiratory and anesthesia gases. Diaphragm-poppet designs are great solutions in leak testing devices, due to the very low leak rate. Lastly, these designs are suitable for critical or contaminated vacuum applications.
Spoppet-design valves
Spoppet-design valves combine two designs to provide a blend of primary poppet sealing in conjunction with a minimal number of sliding seals, thus emulating characteristics of a poppet and spool valve design. Spoppet designs retain some unbalance characteristics but with some balance of pressure to reduce actuation forces. This design provides the benefits of the poppet valve with a reduced sensitivity to lubrication.
Only one sliding seal engaged at a time reduces the drag within the valve body. These designs can sometimes bridge the gaps or limitations of poppet and spool valves making them more useable in numerous critical applications. By blending the designs, spoppets provide more cost efficient 3-way and 4-way valves, and can be used in many different environments and applications.
Spool-design valves
Spool-design valves are available in three types: lapped-/shear-design with no seals, dynamic seals, or O-rings. Spool valves are designed to be more cost-effective when manufacturing for 4-way valves and are conversely less adaptable for 2-or 3-way configurations. Spool valves can be either balanced or unbalanced, depending on desired position control required. Therefore, understanding this valves’ function is critical to the application requirements. Lapped- or shear-design spool valves can operate without lubrication but are less tolerant of variations in lubrication or by-products of compressing the air at the air compressor. Hence, further conditioning of the compressed air is required prior to use.
Dynamic seal spool valves generally require lubrication. Lapped spool valves have higher leak rates that may make them unacceptable for control of medias other than air, or limited media sources (air/gas tanks/bottles). Consequently, these valve designs are better suited to applications in factory automation where the leak rates are not critical. The requirement for conditioned media also limits their use for vacuum where contaminates are ingested into the vacuum lines and valves.
Custom-designed valves
Custom-designed valves are becoming more common, using a combination of the fore-mentioned design technologies to provide solutions unique to the customers’ challenges. In a perfect world, off-the-shelf components would meet every application’s need. But that doesn’t often happen, especially when faced with trade-offs such as space constraints versus performance. Sometimes a complex solution is needed, such as squeezing multiple components into a small space or incorporating multiple valve designs for a solution.
Custom designs using known and proven design technologies offer the potential of lower cost pneumatic systems. Once the specifications are agreed upon with the manufacturer’s design engineers and the application’s product engineers, a custom designed solution may be the best way to meet the applications’ challenges if a specific design is close but not does not meet exact specifications.
Ultimately when it comes to valves, each design technology offers unique capabilities but not every design suits specific applications. No matter whether you are replacing a component or designing a pneumatic system, consult a valve manufacturer who has knowledge in many different design principles so that the best solution can be achieved.
New valve catalog from Humphrey Products
Humphrey Products has released its newest Valve Catalog, HKV-7, for distribution. The new catalog provides basic decision-making information about our broad range of valve products. Within each of the eight sections, there are pages devoted to valve fundamentals, principles and background information, along with a comprehensive index to quickly navigate to the best solution. The ultimate goal of the catalog is to provide an overview of our products, guiding the customer to www.humphrey-products.com for more information.
Once at the website, the customer can access an Online Product Guide, which provides more detailed specifications, CAD drawings, how to order information, and the ability to request a quote for the product. Additionally, the new catalog can be viewed as an interactive PDF.
Valve manifold has world’s smallest footprint
Hauppauge, N.Y.—Festo has announced the development of the high density/small footprint VTOC pilot gas valve manifold. This is the highest density manifold—with up to 48 valves—for its footprint in the world, because the manifold features two 3/2-way valves on each valve position and valve widths of only 0.393 in. (10 mm).
The VTOC manifold is ideally suited for pilot valve gas box applications in the semiconductor industry as well as pilot valve manifolds in the processing industry. The VTOC may also be applied where exceptionally small pneumatic actuators are utilized such as in pharmaceutical and electronics manufacturing. Valve airflow is 10 normal liters (NI)/min.
OEMs will find a host of standard configurations from which to choose. The Festo online configurator helps to ensure fast and accurate ordering. The VTOC offers a number of port patterns to facilitate a variety of mounting options, including bottom ports for bulkhead mounting.
Other VTOC options include: configurable manifold rails (pneumatic and electric connections), multi-pin plug connection with sub-D plug or flat ribbon cable, valve with non-detenting manual override, and choices of pneumatic outlets – QS push-in connectors, straight, or angled. Also optional are individual contacts for each coil – separate commons – and diodes to ensure the current is in only one direction. This can be used to increase safety in user circuits.
“The value of the VTOC is in its high density and small footprint along with the high number of standard variations available,” said Frank Latino, product manager, valve terminals and electronics, Festo. “The VTOC was designed for the OEM looking to lower the cost of design, ordering, and installation, while having the greatest flexibility in valve manifold capabilities.”
Pilot-operated check valves
Pneumadyne’s new pilot-operated check valves are suitable for reliably holding an actuator position in a variety of applications. These rugged valves feature a ¼ or 1/8 NPT output port that mounts directly on a cylinder, minimizing space requirements and easing installation. The input port swivels to accommodate valve alignment and contains a ¼ push-in or 1/8 NPT (F) connection to speed tubing installation. With a maximum operating pressure of 150 psi, these valves provide flow rates up to 22 scfm at 100 psi.
Double valves for clutch/brake circuits
Mechanical press safety standards and good practices require several things in the event of a failure within the valve that controls a pneumatic clutch and brake:
• Air must be exhausted quickly to ensure fast stopping time.
• A monitor must take action to prevent further operation of the press.
• A method to alert personnel should be incorporated.
Double valves, or dual valves, have all of these features and have understandably thus become the press industry’s safety standard for clutch and brake control. These valves incorporate two valve elements which are independently controlled by two solenoid pilots within one valve body. The two valve elements share common inlet, outlet and exhaust ports. When the pilots are simultaneously energized, the elements operate so that the valve functions as a 3/2 normally closed valve.
Double valves, such as the ROSS DM2 Series D products, have built-in self monitoring and can send a signal back to the press controls in case of a valve malfunction. Each independent valve element monitors and cross-checks the operation of the other on each cycle, so that if one side fails to operate properly the valve immediately exhausts the downstream volume to less than 1% of supply pressure. The built-in monitor places the internal elements into a “locked-out” condition which prevents further operation of the valve or the press. A momentary reset signal is required to clear the valve fault and continue operation. An optional status indicator switch can provide “go” or “faulted” signals.
Because double valves provide a level of safety for mechanical press/clutch brake circuits that single element valves, even when externally monitored, simply cannot provide, they are known as “control reliable.” Control reliability is defined as “the capability of a device or system to stop or prevent initiation of hazardous motion in the event of a single component failure within the device or system”. Control reliable devices can be applied anywhere there could be exposure to catastrophic injury. Standardizing on double valves such as the ROSS DM2 Series D will simplify circuits and add a significant measure of safety.
Control reliablility requires:
• Redundancy
• Monitoring
• Further operations to be inhibited
• A defined action to reset
• Failing to a “SAFE” condition
Valve driver provides amplification and linearization
Ernie Doering, a design engineer with Clippard Instrument Laboratory, explains the basic operations, as well as a few key features of the EVP proportional valve driver, in this video.
The driver, which performs amplification and linearization, is touted as a flexible tool for design engineers. See the video below.
Clippard Instrument Laboratory
Miniature pneumatics for medical and scientific applications
Cincinnati, Ohio—Clippard Instrument Laboratory provides the scientific/medical industry a variety of products and solutions. The product range is illustrated in a color brochure featuring the most complete line of miniature fluid power products for the medical, pharmaceutical analytical and dental fields. Some of the many products include electronic valves for Oxygen-enriched environments, check and control valves, proportional valves, regulators, fittings, tubing and more.
A complete line of more than 5000 standard products, coupled with proven engineering and application expertise makes Clippard an suitable choice when seeking unique design solutions.
Clippard Instrument Laboratory
Valves for leak testing
Perhaps the most important factor in leak testing is the valve used to leak test. If the valve is not reliably leak tight itself, the testing efforts are a waste of time. ROSS’ high-flow, bubble tight Dale Series LT, CX and LX valves and manifolds have patented poppet design and exceptional sealing capabilities.
The Dale Series LT, CX and LX valves help streamline processes with their high flow (thus reducing testing time) and offer a broad pressure range of high vacuum up to 250 psi for flexibility. The LT, CX and LX valves are pressure independent so that pressure or vacuum can be applied to any port at any time. The valves feature low wattage coils that reduce energy consumption and help avoid unnecessary valve heat. For further convenience, these bi-directional valves are offered with compact manifolds which eliminate piping (and potential leak paths) and spacing between valves, and provide simplified installation.
Beyond their basic leak testing proficiency, the Dale Series LT, CX and LX valves are versatile and provide many application-specific benefits. In channel select applications, for example, customers are able to test multiple parts at a time or multiple chambers in a single part. And with bypass fill and exhaust applications, the Dale Series valves’ high-flow design can improve cycle time and be used as an exhaust valve, helping prevent contamination to other units.
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