Showing posts with label industrial valve. Show all posts
Showing posts with label industrial valve. Show all posts

Friday, February 23, 2018

Industrial Diaphragm Valves

sectional drawing weir type diaphragm valve with pneumatic actuator
Section drawing of diaphragm valve, weir type,
with pneumatic actuator.
Image courtesy Gemu Valves, Inc.
Diaphragm valves are named for the means employed in their design to restrict the path of fluid flow through the valve. Most valve designs employ a rigid solid shape which is repositioned in the fluid path to regulate flow. Diaphragm valves are somewhat unique in their use of a flexible material that is deformed by a moving part connected to the valve operating mechanism. The diaphragm acts as the flow restrictor and seat. It also isolates the valve bonnet and stem from the flowing media.

The fluid path and diaphragm positioning and seating enable this valve type to be used for throttling or simple stop operations. They are generally tolerant of particulate matter entrained in the media. Selecting body and diaphragm materials that are compatible with the media are primary elements of achieving a successful application. The diaphragm is a wearing part and should be inspected periodically and replaced when necessary.

Diaphragm valves for industrial use are available in a range of materials and sizes to accommodate light through heavy duty applications.
  • Suitable for inert and corrosive liquid and gaseous media when proper valve body and diaphragm materials are selected
  • Bonnet and valve bodies available in metal or plastic construction
  • Insensitive to particulate media
  • Valve body and diaphragm available in various materials and designs
  • Compact design
  • Automation via pneumatic or electric means
Share your fluid process control challenges with valve application specialists. Leverage your own knowledge and experience with their product application expertise to develop an effective solution.

Wednesday, February 7, 2018

Plug Valves - Right For Your Application?

industrial plug valve with manual operating handle
Plug valves incorporate design features making them
a positive choice for many fluid process applications.
Image courtesy Fluoroseal, Inc.
There are common components to be found on almost every process system that involves fluid control. Regardless of the operation's scale, pumps, piping, tanks and valves are likely to be part of the system.

Valves, of which there are many types, provide control over the flow rate, direction and routing of fluids in a processing operation. Flow can be started, stopped or modulated between zero and full rate using a properly sized and configured valve. Some valves enable media flow to be diverted to a selection of outlets, in lieu of a single inlet and outlet pair. Specialized valves regulate inlet or outlet pressure, or prevent fluid flow from going in an undesirable direction. All of these capabilities are packaged into differing valve product offerings that present a very large selection array to a process designer or engineer.

Industrial flow control valve types are generally classified according to the structure or arrangement contained within the valve body that provides obstruction to fluid flow. Some of the common types are ball, butterfly, gate, globe, and plug. Surely, there are more valve types, and this article is not intended to list them all. Some of our previous blogs have discussed selection considerations for gate, ball and butterfly valves. This article will focus on one of the oldest valve types, the plug valve.

Plug valves, like ball and butterfly valves, span from fully open to fully closed positions with a shaft rotation of 90 degrees. The “plug” in a plug valve is installed in the flow path within the valve body and rotated by means of a stem or shaft extending to the exterior of the body. Plugs are often tapered toward the bottom and are fitted to a seating surface in the valve body cavity that prevents fluid from bypassing the plug. An opening through the plug, the port, can be shaped to provide particular flow characteristics. There are numerous variants of the basic plug valve which may make it suitable for particular applications. One common variant is the lined or sleeved plug valve, with an insert or interior lining of material that creates an isolating barrier between the valve body and the media. This allows use of less expensive materials for the body construction that may be otherwise subject to corrosion by exposure to aggressive media.

Positive attributes of plug valves.

  • 90 degree rotation from open to closed provides fast operation.
  • With proper configuration, can be well suited for frequent operation.
  • Availability of corrosion resistant liner may provide comparative cost savings because valve body can be constructed of less expensive material.
  • Design is simple and employs a low parts count.
  • Valve can be serviced in place.
  • Generally, low resistance to flow when fully open.
  • Reliable leak-tight service due to tapered plug wedging action, replaceable sleeve, and injection of lubricant in some variants.

Potential issues of concern.

  • Higher friction in the plug closure mechanism may require comparatively higher operating torque than other valve types.
  • Without a specially designed plug, generally not well suited for throttling applications.
  • Rapid shutoff delivered by plug design may not be suitable for some applications where hammering may occur.

Share your fluid control application challenges with a valve and automation specialist. Leverage your own knowledge and experience with their product application expertise to develop an effective solution.

Thursday, January 25, 2018

Krombach Brand Valves for Rugged Service Conditions

metal seated butterfly valve with actuator
Metal seated butterfly valves for aggressive process
applications are a hallmark of the Krombach brand.
Image courtesy Crane CPE
The Krombach branded valves, part of the Crane CPE product offering, target challenging applications in industrial settings that benefit from the use of valves specially designed for severe service. The brand also includes a standard product offering of valves and specialties for a broad range of common industrial applications.

The Krombach line includes:

  • Butterfly Valves - High performance, resilient seated, double-eccentric, triple offset and special purpose butterfly valves.
  • Ball Valves - Process one-piece, two-piece and three-piece, metal seated, soft seated and compact ball valves.
  • Globe and Angle Valves - Bronze, cast iron, cast steel and stainless steel globe and angle valves.
  • Gate Valves - Bronze, cast iron, cast steel and stainless steel gate valves.
  • Check Valves - Ball, dual-plate, foot, full body swing, steam stop, tilting disc, wafer style swing, nozzle-type and pressure seal check valves.
  • Vacuum Relief Valves - Available with flanged or threaded connections.
  • Aerating and Deaerating Valves - Essential for trouble-free operation of pipeline systems handling liquids.
  • Float Valves - Single seated and double seated versions for a variety of applications.
  • Throttle Valves - Available with flange connection, wafer- or weld-in type.
  • Bottom Drain Valves - Available manually operated or with a diaphragm actuator.

Below is a cutsheet providing an overview of the company's standard product categories. Whatever your fluid control application, share your challenges with the valve specialists at MSEC. Leverage your own process knowledge and experience with their product application expertise to develop effective valve and automation solutions.


Wednesday, October 11, 2017

Ball Sector Valves

industrial ball valves with actuators
Industrial ball sector valves with a variety of actuators
Image courtesy of Schubert & Salzer
The manufacturers of valves and other fluid control components for the processing industries have never been shy about tweaking designs to deliver better performance for a particular set of operating conditions. The available basic valve designs, along with their variants, create an immense catalog of potential candidates for each application.

One such design variant is the ball sector valve. It is a quarter turn valve, like its cousin the ball valve, but the trim is different. True to its name, the active closure structure is but a portion of what we know of as a common ball valve. Where a ball valve essentially has a sphere with a hole drilled through it, a ball sector valve more resembles a section of a hollowed out sphere with a shaped opening in the surface.

ball sector valve animation
Ball sector valve is a quarter
turn valve.
Image courtesy Schubert & Salzer
The closure in a ball valve can be floating or trunnion mounted. A ball sector valve will have a trunnion style mounted closure, with rigid support at the top and bottom. Ball valves, with their rotating fluid pathway resembling a short tube, are generally not the best option for flow control other than isolation. The ball sector valve functions similar to a sliding gate valve, providing an increasing or decreasing elliptical shaped opening as the shaft is turned.

Ball sector valves are well suited for applications involving isolation or control of viscous fluids, slurries, and other challenging fluids. Because of the construction and centric trunnion mounting, the seal area on the ball sector valve is kept free of the media, leading to reduced wear and superior longevity.

There are some good cutaway illustrations in the brochure included below that detail the valve construction. Share your fluid control challenges of all types with valve specialists, leveraging your own process knowledge and experience with their product application expertise to develop an effective solution.




Wednesday, June 7, 2017

Metal Diaphragm Valves - Best Applications

pneumatically operated diaphragm valve industrial valve
Diaphragm valve, pneumatically actuated
Courtesy GEMU
There are more valve selection options available than one can count. Differing types, sizes, materials, and other special characteristics distinguish each and every product as unique in its own way. Matching the design and performance strengths of a particular valve to the requirements of an application may require some investment in time and research, but the payback can be years of trouble free performance.

Diaphragm valves are beneficial for applications requiring hermetic isolation of the valve bonnet and stem from the media. The diaphragm serves as the isolating barrier. The valves are generally tolerant of particulate matter entrained in the media, and provide good shutoff and throttling capability. Body and diaphragm materials should be selected that are compatible with the media.

Body styles are either weir or straight through design. Straight through body styles offer a less restricted flow path than the weir type, but diaphragm movement in the weir style is reduced. Diaphragms do wear and will need to be replaced at some point. Valves should be installed with good service access.

There are many variants of diaphragm valves, broadening their suitability for a wide range of industrial applications. Share your fluid process control challenges with application specialists, combining your process knowledge with their product expertise to develop effective solutions.

internal diagram of weir type diaphragm valve
Weir body style diaphragm valve
Coutesy GEMU

Monday, May 22, 2017

Introduction to Valve Parts or Components

cutaway view forged steel gate valve
Cutaway view of a forged steel gate valve
Courtesy Crane-ChemPharmaEnergy
Although there are many different classifications of valves specific to their respective functions, there are standard parts or components of valves you may find regardless of the classification. They are the valve body, bonnet, trim, seat, stem, actuator, and packing.

The Valve Body is the primary boundary of a pressure valve which serves as the framework for the entire valve’s assembly. The body resists fluid pressure loads from connected inlet and outlet piping; the piping is connected through threaded, bolted, or welded joints.

The Valve Bonnet is the opening of the Valve Body’s cover. Bonnets can vary in design and model, is built using the same material as the Valve Body, and is also connected to the entire assembly through threaded, bolted, or welded joints.

The Valve Trim collectively refers to all the replaceable parts in a valve, e.g. the disk, seat, stem, and sleeves––all which guide the stem as well.

The Valve Disk allows the passage or stoppage of flow. Disks provide reliable wear properties and differ in what they look like per valve type. For example, in the case of a ball valve, the disk is called a ball, whereas for a plug valve it is a plug.

The Valve Seat(s) or it’s seal rings provide surface seating for the disk. For example, a globe valve requires only one seat and this seat forms a seal with the disk to stop flow.

The Valve Stem provides the proper position which will allow the opening and closing movement of the Valve Disk. Therefore, it is connected to the Valve Disk on one end and the Valve Hand Wheel or the Valve Actuator on the other.

The Valve Yoke is the final piece in the valve’s assembly; the Yoke connects the Valve Bonnet with the actuating mechanism. The Valve Stem passes through the top of the Yoke which holds the Yoke or stem nut.

There are countless variants of valve designs, sizes, and configurations. These basic parts will be found on most, but the particular form and arrangement of the part may provide an advantage when employed for a particular application. Share your industrial process valve requirements and challenges with a valve specialist. Combine your own process knowledge and experience with their product application expertise to develop an effective solution.

Tuesday, March 21, 2017

Forged Steel Valves for the Toughest Applications

cutaway view forged steel gate valve with handle and weld socket connections
Forged Steel Gate Valve
Cutaway View
Courtesy Crane ChemPharma Energy
Forging steel produces material of greater overall strength and toughness for parts and assemblies subjected to higher levels of stress. Forging is basically accomplished by applying localized mechanical pressure across the base steel, eliminating internal voids and gas pockets, while producing a unique oriented grain structure in the metal that delivers increased fatigue resistance.

Higher pressure or temperature applications in fluid process control can benefit from, and sometimes may require, the use of forged steel valves. Their ruggedness and ability to hold up under tough conditions make forged steel valves a good choice for many uses throughout general industrial, oil and gas, and power generation installations.

Forged steel valves are available in a broad range of sizes, connection types, and port configurations. Crane, world class manufacturer of industrial valves, offers forged steel gate, globe, and check valves to provide options for flow direction, stop, and throttle control.

There are almost countless variants and configurations of industrial valves from which to choose. Share your fluid control requirements and challenges with an industrial valve expert, combining your own process knowledge and experience with their product application expertise to develop effective solutions.


Wednesday, February 8, 2017

Floating Ball Valves

exploded view of floating ball valve
Exploded view of floating ball valve
Courtesy HS Valve
Ball valves are used throughout fluid based applications, from residential to heavy industrial. The compact and rugged design of this valve type provides superior service when properly applied. There are many variants of the basic design, with manufacturers providing builds that meet very specific and stringent requirements posed by certain types of industrial process control applications.

Ball valves are named for the spherically shaped element encased in the valve body directly in the fluid flow path. The ball has a hole, or port, through it’s center, permitting fluid to pass when the port is aligned with the direction of flow. A stem is attached to the ball and extends to the exterior of the valve body, providing a mechanical means of rotating the ball between open and closed positions. Ninety degrees of rotation moves the ball from the fully open to fully closed position. Ball valves are generally suitable for manual or automated operation.

In the basic design of ball valves, there are two groups which exhibit an essential structural difference that is worth mentioning. There are two ways in which the ball in a ball valve is held in place. A floating ball valve has its main trim element held in place by the shape of the valve body and the seats. It is essentially suspended in the flow path by its surrounding parts. A very small amount of lateral movement of the ball is imparted by the fluid flow, pushing the ball tightly against the seat on the downstream side. This attribute enables a floating ball valve to provide tight shutoff of bidirectional flow. The floating ball design proves less effective as the nominal bore size increases. The added weight of the larger ball, coupled with the larger surface area exposed to fluid forces, can overcome the ability of the seals to properly support the ball and maintain good performance. The maximum size can vary among manufacturers.

Enjoying all the benefits of ball valve design, plus being comparatively simple to disassemble and service, floating ball valves are a solid choice for many industrial applications. Selecting the right valve design or type is an important step toward effective control of fluid operations. Share your fluid process control challenges with a valve expert, combining your process knowledge with their product application expertise to develop effective solutions.



Friday, December 2, 2016

Diaphragm Valves For Heavy Duty Industrial Applications

industrial diaphragm valve with handle metal body and metal diaphragm
Series 611 Industrial Diaphragm Valve
Courtesy Gemü
Diaphragm valves are suitably used for applications requiring hermetic isolation of the valve bonnet and stem from the flowing media. They also are capable of throttling flow and are generally tolerant of particulate matter entrained in the media. Selecting body and diaphragm materials that are compatible with the media are primary elements of achieving a successful application.

Gemü, a globally recognized manufacturer of diaphragm valves and other control components, offers a line of industrial metal diaphragm valves available in a range of materials and sizes to accommodate heavy duty applications.
  • Suitable for inert and corrosive liquid and gaseous media
  • Chemical resistant bonnet
  • Insensitive to particulate media
  • Valve body and diaphragm available in various materials and designs
  • Compact design
Share your fluid process control challenges with application specialists, combining your process knowledge with their product expertise to develop effective solutions.

Wednesday, September 7, 2016

Severe Service Valves - Application Targeted

severe service flanged plug valve lined Fluoroseal
Sever Service Plug Valve
Fluoroseal
Industrial process control applications can be associated with some very stringent and challenging performance requirements for the physical equipment and components that are part of the process chain. In fluid based operations, the control and shutoff valves can be a significant impact point of extreme fluid conditions, requiring careful design and selection consideration to assure proper performance and safety levels are predictably maintained.

Industrial valves that are intended for application at the extremes are generally referred to as severe service valves. While there are plenty of published and accepted standards for industrial valves, one does not exist to precisely define a severe service valve. There is, however, some movement toward the development of severe service standards in some industry segments.

So, how do you know when to focus valve selection activities on severe service valves, as opposed to general purpose valves? There are a number of basic criteria that might point you in that direction:
  • Very extreme media or environmental temperature
  • High pressure drop operation that may cause cavitation
  • Rapid and extreme changes to inlet pressure
  • Certain types or amounts of solids contained in the fluid
  • High number of mechanical operations
  • Thermal cycling
Certainly, any of these criteria might be found in an application serviceable by a general purpose valve, but their presence should be an indicator that a closer assessment of the fluid conditions and commensurate valve requirements is in order. The key element for a process stakeholder is to recognize when conditions are in evidence that might overrun the capabilities of a general purpose valve, leading to premature failure in control performance or catastrophic failure that produces an unsafe condition. Once the possibility of a severe service condition is identified, a careful analysis of the possible operating conditions will reveal the performance requirements for the valve.

There are numerous manufacturers of severe service valves, each seeming to concentrate on a particular niche. Fluoroseal, a globally recognized manufacturer of lined valves for corrosive applications, has their own entry in the severe service arena that is based upon one of their popular general purpose valves. The focus for the FE Series valve design appears to be thermal cycling, excessive number of mechanical operations, and fugitive emissions.

I have included a technical bulletin that describes and nicely illustrates (with a cutaway view) the various features incorporated in the valve design.

You can always get more information, or discuss your special requirements, with a product application specialist. They have access to technical resources that can help with selecting the right valve configuration to meet your severe service applications.

Tuesday, May 24, 2016

Check Valve Incorporates Useful Features For Industrial Process Fluid Systems

Large industrial check valve
Check valve with integral straightening vanes
Courtesy Titan Flow Control
A check valve allows fluid flow in one direction (forward) and prevents it in another. They are employed extensively in industrial and commercial piping systems to prevent the reverse flow of a fluid that would produce an undesirable effect. Numerous sizes and types are available to meet specific application challenges. Each check valve must be properly selected to accommodate the pressure, temperature, and flow characteristics of each system. Proper materials of construction must be selected to provide suitable service with the process media.

Check valves are commonly applied to protect pumps from any induced reverse flow in a system. They can also be found in combination with other valves, providing assurance that the process fluid flows only in one direction.

One manufacturer, Titan Flow Control, incorporates a number of features into a single unit to provide wide ranging application. Features of the check valve are detailed below, along with a data sheet with more technical information. You can always get the latest available product data and solid application assistance from the process control specialists at Mountain States Engineering. Combining your process knowledge with their product application expertise will yield a positive outcome.


Friday, April 15, 2016

New Triple Offset Valve From Crane

Triple offset butterfly valve for industrial process control
FKX 9000 Triple Offset Butterfly Valve
Courtesy of Crane CPE
Crane ChemPharma Energy, a globally recognized manufacturer of industrial process control valves for an extensive range of industries and applications, has developed and released a new addition to its line of triple offset butterfly valves. The FKX 9000 series incorporates innovative design features to bring longer valve life, cost reduction, and superior performance in industrial applications where high temperature, high pressure, and severe service are present.

The new valve series is available in sizes ranging from 3" to 24", with three body configurations and a host of special options for tailoring to specific applications. A flyer is included below that highlights the features of the new valve. More detailed information, as well as help with meeting all your fluid process control challenges, is available from the product knowledge and application support specialists at Mountain States Engineering.


Monday, April 4, 2016

Who Is OMB Valve?


large 42" industrial trunnion mount ball valve for oil industry
42" Trunnion Ball Valve
Courtesy OMB Valves
Mountain States Engineering offers the OMB line of valves for the transportation and energy industries throughout the western states. OMB has been a manufacturer of forged steel valves since 1973, starting business in Italy and establishing a presence in every major energy producing region of the world. North American operations are supported from the Stafford, Texas plant which has expanded to over 100,000 square feet.

OMB manufactures globe, ball, gate, and check valves with a broad range of variants to meet diverse requirements throughout the world. The company is well known for is line of forged steel valves, but OMB also fabricates using other materials, including specialty alloys.

Review the company's full product line below. Contact the valve application specialists at Mountain States Engineering for additional product information or assistance meeting any industrial or process control valve challenge.


Friday, April 1, 2016

Video Demonstration of Weir Diaphragm Valve Operation

industrial diaphragm valve sectional view for process control
GEMU 620 Industrial Diaphragm Valve
Diaphragm valves comprise one of many different process control valve designs, each with specific attributes making them better suited for certain applications. Selecting the right valve type for an application is a critical early step toward successful control implementation.

Familiarity and understanding of how a particular valve type functions is necessary when equipping a fluid control system. Here are some considerations for valve operation that come into play.

  • Media Compatibility:
    Industrial process control applications cover an immense range of viscosity, velocity, solids content, and other physical media characteristics that may, or may not, be acceptably addressed by some valve types.
  • Cycle Frequency:
    Some valve types are more suitable for a high frequency of on/off cycles, others are better suited to slower rates.
  • Compatibility With Sanitary or Similar Operations:
    Some industries have requirements for special cleaning, sanitizing, or sterilizing of the process flow path. A valve design that does not trap the media within the valve body and allows for full exposure of the fluid path to whatever cleaning agent is applied has certain advantages for these applications. Some cleaning operations also require a full bore or straight through flow path to allow for proper cleaning.
  • Operating Speed:
    Different valve types may have varying capabilities to provide rapid change of valve position. Valve operating speed must be compatible with process requirements that may call for either rapid or slow opening or closing.
  • Throttling Ability:
    Each valve type, through the characteristics of its closure mechanism, offers comparatively different capacity for regulate fluid flow across an extended range between completely closed and fully open.
  • Space Requirements:
    Different valve trim arrangements can predicate how much installation space a valve may require for proper operation and maintenance. For example, a valve with a rising stem will generally require more clearance than a similar capacity valve with a rotating stem.
Industrial process control diaphragm valve Gemu
GEMU Model 620 Industrial Diaphragm Valve
Certainly, there are more aspects of valve operation that will be taken into account in the selection process. 

Diaphragm valves defend their niche of applications with their ability to:
  • Provide on/off or throttling service
  • Eliminate stem leakage
  • Provide bubble tight service
  • Eliminate pockets that may trap media
  • Isolate valve mechanism from media
  • Prevent contamination of media by valve parts or operation
Below is a short video that provides an animated look inside a weir diaphragm valve. The video provides a clear illustration of how the fluid flows through the valve and how the valve controls flow. There are variants of the diaphragm valve that do not use a weir, providing a straight through or full bore flow path. Their operation is similar.
Watch the video. It's short and to the point. Get the help you need solving your process control valve challenges from the seasoned experts at Mountain States Engineering.
"

Wednesday, March 9, 2016

Sleeved Plug Valves - Design Features and Variants

Industrial process control often involves the management of fluid flow, either by simple on-off flow control, throttling, or diversion of flow to alternate destinations. Valves of many differing designs and construction features provide distinct advantages for particular applications depending upon a variety of media characteristics, operational requirements, physical restrictions, and regulatory requirements.

Plug valves, so named for the generally tapered or parallel sided structure held in the flow path by the valve body, have wide application throughout the fluid control field. Their advantageous features include simple design, low maintenance, moderate size, minimal flow resistance when fully open, and quarter turn operation.
Cutaway view sleeved plug valve for industrial process use
Cutaway view of sleeved plug valve with design features labelled
Courtesy Fluoroseal

One subset of the plug valve family, the sleeved plug valve, has an additional advantage. It does not require lubrication. The metal plug is wedged within a sleeve, usually PTFE or a similar material, which provides a seal around the plug and a self lubricating surface to facilitate rotation of the plug within the body. One manufacturer, FluoroSeal, provides a broad offering of sleeved plug valves. The illustration (left) provides a cutaway view of one of Fluoroseal's valves of this type with primary design features labelled by the manufacturer as follows:
  1. Bidirectional in-line bubble-tight seal independent of line pressure
  2. Multiple external bubble-tight seals independent of line pressure
  3. Direction mechanical three-point adjustment independent of line pressure
  4. Independent travel stops
  5. Full encapsulation and retention of all leading edges of PFE sleeve and top seal components
  6. Full lip at port openings protects PTFE sleeve
  7. Contoured waterway ensures minimum flow turbulence characteristic
  8. No body cavities to entrap flow media
  9. Positive flow direction indication
  10. Drilled and tapped flange actuation mounting pads independent of cover and top sear assembly.

This versatile valve type is available in a number of variants suited to particular applications. Thes variants include:

  • Multiport configurations for flow diversion.
  • Caged plug version for use with a range of abrasive fluids
  • Double block and bleed design
  • Fire safe versions with additional sealing and venting to prevent leakage if the valve is overheated in a fire
  • Severe service variant to provide tight emission control and suitability for demanding applications with thermal cycling or a high operating rate
  • Special cleaning, testing, production methods, or other specialized tasks needed to assure safety or performance under very specific application conditions found in various industries.
An illustrated document with technical performance data for much of what is described above is included below. Browse the document for a more complete understanding of where sleeved plug valves can be applied and how they work. For more information, contact a valve specialist. Share your fluid control challenges with them and work toward a winning solution. The combination of your process expertise and their deep product application knowledge will yield good results.




Tuesday, February 16, 2016

Specialized Gate Valve For Control Applications

Sliding gate process control valve
Sliding Gate
Process Control Valve
Schubert & Salzer
Gate valves are widely employed throughout the industrial process control field to start and stop the flow of a wide range of fluids and slurries. The common construction of a gate valve, with a solid wedge or disc that moves perpendicularly to the direction of fluid flow, tends to limit the application of this valve type to processes where fully open or fully closed are the desired valve positions. The comparatively large travel range of the wedge from open to closed, combined with a need to close the valve slowly to avoid hammering, saddles the common gate valve with a slow operating speed. Holding the gate at a partially open position has potential to induce vibration in the fluid, resulting in noise and possible negative impact on the fluid transport system. For this reason, common gate valves are generally not used in control applications requiring flow modulation .

The limiting factors just described can be mitigated or eliminated with a modification to the gate configuration. Instead of a solid gate, two plates with matching orifice matrices are mounted in the fluid path. One plate is fixed and the other is moved by the valve actuator, sliding through a motion range that expands flow area by increasingly matching the orifice openings on the two plates. This gate valve design is often called a sliding gate valve and it is easily recognizable through its pattern of slotted openings on the gate.

Some notable features of the sliding gate valve:

  • Straight through flow path with little turbulence.
  • Flow is broken into multiple small streams by the orifice pattern, reducing the impact of the flow force on the valve trim.
  • Suitable for fluid control operation, not just fully open or closed.
  • Travel distance and time from fully open to fully closed is significantly reduced, when compared to common gate valve.
  • Quieter operation.
  • Long service life.
  • Suitable for lower viscosity, generally clean, fluids
Every valve design has applications where it will tower over others in terms of overall performance. The variable orifice control valve (sliding gate valve) will prove to be the best choice for certain applications. Share your fluid process control challenges with an industrial control specialist. Combining your process expertise with their product application knowledge is a sure way to produce positive outcomes. 


Tuesday, January 26, 2016

Valve Preparation For Oxygen or High Purity Service

Hazmat symbol for oxygen
Oxygen is used extensively throughout a wide range of industrial processes. Medical, deep-sea, metal cutting, welding, and metal hardening are a few examples. The steel industry uses oxygen to increase capacity and efficiency in furnaces. As a synthesis gas, oxygen is also used in the production of gasoline, methanol and ammonia.

Odorless and colorless, oxygen is concentrated in atmospheric air at approximately 21%. While O2, by itself, is non-flammable, it vigorously supports  combustion of other materials. Allowing oils or greases to contact high concentrations of oxygen can result in ignition and possibly explosion. Oxygen service preparation of an industrial valve calls for special cleaning processes or steps that remove all traces of oils and other contaminants from the valve to prepare for safe use with oxygen (O2). Aside from the reactive concerns surrounding oxygen, O2 preparation is also used for applications where high purity must be maintained and valves must be free of contaminants.

Gaseous oxygen is noncorrosive and may be used with a variety of metals. Stainless steel, bronze and brass are common. Liquid oxygen presents unique challenges due to cryogenic temperatures. In this case, valve bodies, stems, seals and packing must be carefully chosen.

Various types of valves are available for oxygen service, along with a wide array of connections, including screwed, socket weld, ANSI Class 150 and ANSI Class 300, DIN PN16 and DIN PN40 flanged ends. Body materials include 316 stainless steel, monel, bronze and brass. Ball and stem material is often 316 stainless steel or brass. PTFE or glass filled PTFE are inert in oxygen, serving as a common seat and seal material employed for O2 service.

Common procedures for O2 service are to carefully deburr metal parts, then meticulously clean to remove all traces of oil, grease and hydrocarbons before assembly. Valve assembly is performed in a clean area using special gloves to assure no grease or dust contaminates the valve. Lubricants compatible with oxygen must be used. Seating and leakage pressure tests are conducted in the clean area, using grease free nitrogen. Specially cleaned tools are used throughout the process. Once assembled, the valves are tested and left in the open position. A silicone desiccant pack is usually inserted in the open valve port, then the valve ports are capped. A warning label about the desiccant pack's location is included, with a second tag indicating the valve has been specially prepared for oxygen service. Finally, valves are individually sealed in polyethylene bags for shipment and storage. Different manufacturers may follow slightly differing protocols, but the basics are the same. The valve must be delivered scrupulously contaminant free.

The O2 preparation of valves is one of many special production variants available to accommodate your special application requirements. Share your valve requirements and challenges with a valve specialist to get the best solution recommendations.

Tuesday, December 29, 2015

Pneumatic Actuator For Corrosive Environments

Corrosion Resistant industrial valve pneumatic Actuator disassembled
Commando XL Corrosion Resistant
Pneumatic Valve Actuator
Courtesy Hytork - Emerson
Industrial process control operations sometimes call for equipment to be placed in physical locations or environments that are not conducive to a long and productive component lifespan. Extremes of temperature, humidity, and vibration can have substantial effect on equipment performance and longevity. Deleterious impact can also arise from elements of the process itself, in the form of corrosive liquid or vapor prevalent in the processing area. While most industrial equipment is provided with some level of protection, there are instances where standard coatings and protective materials may not provide adequate resistance to the deteriorating impact of their installation environment.

Valves of many types are used throughout industrial processes to provide control of fluid flow, with quarter turn movement being one of the more prevalent.
Pneumatically powered quarter turn valves have an actuator option that provides a high level of corrosion resistance, along with the field proven performance of a recognized leading product. 
Hytork™, an Emerson brand, offers their XL line of actuators with a special treatment to withstand aggressively corrosive environments. The corrosion resistant version has been labelled "XL Commando" and, in the company's own words, has...
A durable Fluoropolymer impregnation (using CORROGARD-CG941) of the actuator body parts (inside and out) for maximum corrosion resistance. This durable impregnation can best be achieved in cast aluminum parts (all XL COMMANDO body parts are cast aluminum). As the aluminum metal grains are expanded under heat the CORROGARD-CG941 is applied, entering the grain structure and, upon cooling, is locked at the surface, integral with the grain structure. Extruded surfaces can only be coated and are more susceptible to scratches and other mechanical deterioration.
You can review the performance range, sizes, and other features of these pneumatic valve actuators through a review of the document included below. Bring your process challenges to a valve application specialist and combine your process knowledge with their product application expertise to achieve a solid practical solution.



Wednesday, December 9, 2015

A Close Look at Butterfly Valve Seat

Butterfly valve soft seat cutaway view
Cutaway View of Butterfly Valve With Soft Seat
Courtesy Flowseal - Crane CPE
Butterfly valves are found throughout the fluid based applications in the process control field. They are one of many common and special types of industrial valves used to regulate fluid flow in ways that are compatible with the media being controlled and the degree of precision needed to produce the desired process outcome.

The industrial process control field benefits from a large array of valve manufacturers in pursuit of the favor and business of process operators. Operators continually seek better performance and lower life cycle costs. Manufacturers respond with increasingly improved designs.

A butterfly valve has a disc that is positioned in the fluid flow path. It rotates around a central axis, the stem, through a 90 degree arc from a position parallel to the flow direction (open) to perpendicular (closed). A critical element of a butterfly valve is the seat, where the disc seals to the body in the closed position. Seat design should provide these positive operating attributes:
  • Low friction to reduce valve operating torque
  • Resistance to wear
  • Arrangement that provides for easy replacement
  • Seal or shutoff tightness appropriate for the application
Flowseal, part of the Crane, CPE group of brands, utilizes their specially designed Soft Seat valve sealing arrangement on their resilient sealed butterfly valves. The Soft Seat feature provides beneficial fulfillment of process requirements for the attributes listed above. The valve is available in a range of sizes, with options and variants to meet a wide array of industrial process requirements.

Learn more about the Flowseal Soft Seat butterfly valves by watching the short video below. You can delve deeper with a browsing of the illustrative brochure that is also included below. It provides some detailed illustrations of how the seat functions under differing operating conditions. Contact a product specialist and share your process challenges. Your process knowledge and their product application expertise, when combined, will produce a useful solution.


Tuesday, November 24, 2015

Special Solenoid Valve for Pneumatic Valve Actuators

Industrial Valve With CATS Solenoid Valve Control
Industrial Valve Actuators With
CATS Solenoid Control
Courtesy Emerson Hytork
In our industrial process control operations, we strive for uninterrupted reliable operation of control valves to maintain safe conditions and produce the desired process outcomes. Let's look at pneumatic valve actuators and their control solenoids. Hytork™ has a well thought out solution to enhancing actuator performance and longevity with their CATS solenoid valve. Instead of paraphrasing, I share the manufacturer's own words describing the operational benefits...

Hytork™'s 'CATS' (Clean Air To Springs) is a solenoid valve designed specifically for superior operation of pneumatic actuators. 
All spring return actuators that use a 3-way solenoid valve require air to enter and leave the spring chambers. As compressed air is introduced to the actuator to push the pistons apart, air from the spring chambers must be allowed to vent. During the fail or spring stroke, the compressed air between the pistons must exhaust to permit the springs to drive the pistons together. This piston movement creates a vacuum in the spring chambers which is usually filled by ambient air that may contain dirt, abrasives, corrosives and moisture of which are bad for the actuator - reducing its performance and life. 
A wrong solution for this problem is the use of a 4 way solenoid valve (sometimes referred to as "air assist"). It does prevent the ambient air from entering the actuator, but it will also pressurise the spring chambers. The actuator now acts like an air to open, air to close unit. In the unlikely event of a spring breakage or if the valve torque increases, due to line media build up within the valve, the actuator would still appear to operate normally until its fail action was needed in an emergency. At this most critical time, with supply air not available, the actuator could not perform as intended and it's function as a safety device would be defeated.
Hytork™'s CATS solenoid valve prevents this undesirable action from happening.
As the solenoid is de-energised, permitting the springs to push the pistons together, an internal by-pass in the CATS valve permits some of the exhausting air to fill the spring chambers at atmospheric pressure while the remainder exhausts to atmosphere. No ambient air enters the actuator.
Only clean supply air gets into the actuator - Air that was normally planned to be vented!-There is no pressure build up that can lead to false torque availability on the fail stroke, as in the case of air assisted springs! No extra clean compressed air is used!
The solenoid valves are available in a number of configurations to accommodate almost any installation. To summarize, the advantages include:

  • Maximises actuator life.
  • Reduces installation and initial costs.
  • Prevents actuator seal failure.
  • Prevents corrosives from entering actuator.
  • Prevents dirty air from entering actuator.
  • Proves that the actuator springs are working correctly every stroke.
  • NAMUR standard - Easiest assembly possible - only two mounting screws.
  • Eliminates brackets and tubing - mounts directly to the NAMUR pad on the actuator.
  • Only one style of solenoid valve required for Spring Return and Double Acting actuators - reducing inventory costs.
To explore how these solenoid valves can improve your pneumatic valve actuator operation and longevity, contact a product specialist and share your requirements. Combining your process expertise with the product application knowledge of a professional sales engineer will move you quickly toward a good solution.