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

Tuesday, August 14, 2018

Industrial Control Valve Basics

Understanding industrial control valve design and operation is very important if you work as a process engineer, a plant maintenance person, or if you design process control loops. Control valves are used extensively in power plants, pulp and paper mills, chemical manufacturing, petro-chemical processing, mining facilities, HVAC and steam distribution systems.

There are many types, manufacturers, body styles, and specialized features, but the they all share some basics operating principles. The video below explains components, operation, and fundamentals of how control valves operate.

https://mnteng.com
303-232-4100

Monday, July 23, 2018

Introducing VSI Controls Control Valves

VSI Controls
VSI Controls™, a newly-formed control valve company and wholly-owned subsidiary of PetrolValves™, offers Customers an exciting alternative to procure general and severe service rotary and reciprocating control valve systems that provide a best-fit solution for their processes.

VSI Controls™ combines the products and technology of Valtek Sulamericana™ - a leading control valves system manufacturer with 35 years’ experience supplying severe service solutions - with the financial strength, global infrastructure and manufacturing and technical prowess of PetrolValves™.

Company Strengths
  • A long history of technology and innovation originating from Valtek Sulamericana™. 
  • The financial strength and global infrastructure of PetrolValves™ 
  • A highly experienced and skilled technical team of control valve experts
Their product offering can be reviewed in the embedded document below, or you can download a PDF of the VSI Controls Control Valve Catalog here.

For more information, contact Mountain States Engineering & Controls by visiting https://mnteng.com or calling 303-232-4100.


Thursday, October 26, 2017

When to Use a Globe Valve for Fluid Process Control

cast iron globe valves
Cast iron globe valves are utilized extensively in steam,
HVAC, and other commercial and industrial applications
Image courtesy of Crane Co.
Industrial process control often involves the regulation of fluid flow. There are almost uncountable types and variants of flow control valves, each with a particular set of attributes that can make it the advantageous choice an application.

When the process calls for controlling flow over a range of possible values, known as throttling, a globe valve may be a good candidate for the application.

Globe valves are characterized by the change in direction of fluid flow as it passes through the valve and around the plug positioned in an opening through which fluid must pass. The plug is connected to a stem extending to the exterior of the valve body through the bonnet. Movement of the stem will reposition the plug in relation to the opening, providing a successively larger or smaller opening area through which fluid can pass.

Globe valves are available in tee, angle, and wye configurations, as well as an enormous range of special configurations to suit specific applications.
simplified globe valve diagram
Simplified globe valve diagram
Image courtesy Wikipedia


What are some potential advantages of globe valves?
  • Good throttling and shutoff capability
  • Comparatively easy maintenance
  • Comparatively short travel of plug from open to closed position
  • Seats can usually be resurfaced when worn
What are some limiting factors for globe valves?
  • Higher valve pressure drop than some other designs
  • No straight through fluid path
  • Potentially higher actuator torque requirements than other valve types
  • Seal area is unprotected from exposure to process fluid flow
When flow throttling capability is the overriding concern for an application, a globe valve is a good candidate for consideration. Share your flow control challenges with valve and automation specialists. Combining your process knowledge and experience with their product application expertise will produce effective 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, July 19, 2017

Integrated Solution for Chilled Water Coil Control

integrated sensors, controller, control valve, actuator for HVAC
Monitrol includes controller, sensors, control valve, and
actuator in a single integrated package.
Image courtesy of Warren Controls
The final control element used for heating or cooling via a heat transfer fluid is going to be a control valve, most often one capable of modulating the fluid flow by precise valve positioning. This control activity requires sensors, the control valve, a controller, and an actuator.

Selecting, installing, and coordinating the operation of these components can be challenging and time consuming, especially when the components are sourced from varied manufacturers. Warren Controls delivers a consolidated solution with their Monitrol line of control valves intended for heat transfer control tasks and related operations. The Monitrol concept involves combining pre-engineered and matched controllers and actuators with flow control valves equipped with built-in sensors for pressure, temperature, or flow. Measurement and control is performed locally, with communications between the local and central controllers exchanging setpoint and performance information. The solution is compact and simplified, enabling easy selection, installation, and startup.

More details are provided in the document included below. There are numerous product variants to accommodate a wide array of field applications. Share your fluid control and heat transfer requirements and challenges with an application expert, combining your own facility and process knowledge with their product application expertise to develop an effective solution.


Tuesday, November 8, 2016

Spiral-Trol Valve Disassembly Video

globe valves control valves pneumatic actuator
Globe control valves with pneumatic actuators
Spirax-Sarco
Spirax-Sarco is a globally recognized manufacturer of valves, traps, and a host of other steam system specialties. Their Spira-Trol line of globe valves can be employed throughout a steam of other process fluid system to provide accurate flow regulation. The valves are available with several options of electric or pneumatic actuators, as well as positioning controllers.

The video included below provides a demonstration of the simplicity involved in disassembling the valve in-line for regular maintenance or inspection. The video is short, as is the length of time needed to access the valve internals. These valves are designed for easy maintenance.

Share your fluid process and steam control challenges with application experts. The combination of your process knowledge and their product application expertise will deliver effective solutions.

Tuesday, August 2, 2016

Back Pressure Regulator or Pressure Regulator Valve, Appropriate Application

pressure regulator valve
Pressure Regulator Valve
Courtesy Pentair Cash Valve
Fluids move throughout processes, driven by pressure produced with mechanical or naturally occurring means. In many cases the pressure generated by the driving source is substantially greater than what may be desired at particular process steps. In other cases, the operation may dictate that a minimum pressure be maintained within a portion of the process train. Both cases are handled by the appropriate valve type, designed specifically to regulate pressure.

A pressure regulating valve is a normally open valve that employs mechanical means, positioning itself to maintain the outlet pressure set on the valve. Generally, this type of valve has a spring that provides a countervailing force to the inlet pressure on the valve mechanism. An adjustment bolt regulates the force produced by the spring upon the mechanism, creating an equilibrium point that provides flow through the valve needed to produce the set outlet pressure. A typical application for a pressure regulator is to reduce upstream or inlet pressure to a level appropriate for downstream processing equipment.

Back pressure valves are normally closed, operating in a logically reversed fashion to pressure regulators. Where pressure regulators control outlet pressure, a back pressure valve is intended to maintain inlet pressure.  Similar internals are present in the back pressure valve, with the valve action reversed when compared to a pressure regulator. An inlet pressure reduction in the back pressure valve will cause the valve to begin closing, restricting flow and increasing the inlet pressure. A representative application for a back pressure valve is a multi-port spray station. The back pressure valve will work to maintain a constant setpoint pressure to all the spray nozzles, regardless of how many may be open at a particular time.

Both of these valve types are available in an extensive array of sizes, capacities, pressure ranges, and materials of construction to accommodate every process requirement. Share your fluid control challenges with a process control specialist. Combining your process knowledge with their product application expertise will produce effective solutions.





Wednesday, July 13, 2016

Eight Process Control Valve Selection and Application Criteria

Sliding Gate Control valve with actuator
Sliding Gate Control Valve
Schubert & Salzer
Fluid processes will employ control valves to regulate flow or pressure in between the extremes of fully open and fully closed. Their function and design is specifically different from shutoff valves, which are designed and intended for isolation of segments of a fluid system. Improperly applying or sizing a control valve can have consequences in operation, productivity, and safety ranging from nuisance level to critical. Here are some items that should always be part of your selection  and application consideration.

  • A control valve is not intended to be a an isolation valve and should not be used for isolating a process segment. Make sure you select the appropriate valve for the function to be performed.
  • Select materials of construction that will accommodate the media and the process conditions. Take into consideration the parts of the valve that come in contact with process media, such as the valve body, the seat and any other wetted parts. Operating pressure and temperature impact the materials selection for the control valve, too. Conditions surrounding the valve, the ambient atmosphere and specific local conditions that may expose the valve to corrosives should be included in your thinking.
  • Install flow sensors upstream of the control valve. Locating the flow sensor downstream of the control valve exposes it to an unstable flow stream which is caused by turbulent flow in the valve cavity.
  • Establish the degree of control you need for the process and make sure your valve is mechanically capable to perform at that level. Too much dead-band leads to hunting and poor control. Dead-band is roughly defined as the amount of control signal required to affect a change in valve position. It is caused by worn, or loosely fitted mechanical linkages, or as a function of the controller setting. It can also be effected by the tolerances from mechanical sensors, friction inherent in the the valve stems and seats, or from an undersized actuator.
  • Consider stiction. Wikipedia defines it as "the static friction that needs to be overcome to enable relative motion of stationary objects in contact". This can be particularly evident in valves that see limited or no position change. It typically is caused by the valves packing glands, seats or the pressure exerted against the disk or other trim parts. To overcome stiction, additional force needs to be applied by the actuator, which can lead to overshoot and poor control.
  • Tune your loop controller properly. A poorly tuned controller causes overshoot, undershoot and hunting. Make sure your proportional, integral, and derivative values are set.  This is quite easy today using controllers with advanced, precise auto-tuning features.
  • Avoid oversizing control valves. They are frequently sized larger than needed for the flow loop they control. If the control valve is too large, a small percentage of travel or position change could produce an unduly large change in flow, which in turn can make stable control difficult. Unstable control can result in excessive movement and wear on the valve. Try to size a control valve at about 70%-90% of travel.
  • Think about the type of control valve you are using and its inherent flow characteristic. Different types of valves, and their disks, have very different flow characteristics. The flow characteristic can be generally thought of as the change in rate of flow in relationship to a change in valve position. Globe control valves have linear characteristics which are preferred, while butterfly and gate valves tend to have non-linear flow characteristics, which can cause control problems.  In order to create a linear flow characteristic through a non-linear control valve, manufacturers add specially designed disks or flow orifices which create a desired flow profile.
These are just a few of the more significant criteria to consider when selecting and applying a process control valve. Consider it good practice to discuss your selection and application with a product application expert to confirm your final selection. Combing your process knowledge with their application expertise will provide the best outcome.

Friday, May 6, 2016

Solenoid Valves - A Staple of Process Control

Stainless steel industrial solenoid valve
Series I Solenoid Valve
Courtesy Granzow
The Granzow line of fluid control products for industrial and commercial application includes an extensive array of solenoid valves that are suited for a wide variety of applications. The short video below illustrates the company's offering that covers a broad range of flow rates, orifice and connection sizes, materials of construction, and control options.

More detailed product and application information is available from product specialists. Share your application challenges and work together to develop the best solution.


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, 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.

Friday, June 26, 2015

Selecting The Right Valve Type - Ball Valves

Applications that can be characterized as industrial fluid handling or process control are vast in number and variety, each being highly specialized and customized to specific circumstances. It’s no surprise that, given the array of potential application conditions, there are countless different valve arrangements, types, and technologies to choose from.
Industrial Ball Valve
Large Industrial Ball Valve
Courtesy HS Valve Co.
Ball valves, like many valve types, are named for their closure mechanism. A spherical shaped element is placed in the fluid flow path, with the ability to rotate its position around an axis. The axis is a shaft or other device that connects to an actuator on the exterior of the valve and flow path. The actuator can be a simple handle or an element of a valve automation system. The “ball” in the ball valve has an opening through its center, usually round to mimic the shape of the connected pipe. As the ball is rotated, the opening aligns with the inlet an outlet of the valve body, allowing fluid to pass. A counter-rotation that aligns the opening with the sides of the valve body, away from the flow path, stops the fluid flow. So, compared with other valve technologies, when would a ball valve be a preferred application choice? Here are some points to consider.

Application advantages of ball valves:

  • Leak-proof service
  • Well suited for processes requiring only full flow or no flow operation.
  • Rapid open and close action, requiring only 90 degrees of rotation from fully open to fully closed.
  • Comparatively light weight and small size.
  • Wide range of construction material options for body, ball, and seals make them suitable for many applications.
  • Require only moderate force to control valve position.
  • Flow path opening in the ball will often be “full port”, providing same cross section as the connected pipe and adding very little restriction or pressure drop to the flow.
  • Low maintenance, with no lubrication required.

What considerations might be cause to consider a different valve type?

  • There can be some residual fluid trapped in the valve when it closes.The trapped fluid will be released when the valve is opened. Consider what impact, if any, this may have on your process.
  • Balls valves are generally not suited for throttling applications. When partially open, the seals that surround the ball are exposed to the flow velocity and can deteriorate quickly.
  • Valve seals are usually elastomeric materials. Verify seal materials are compatible with the fluid type, character and operating temperature.

These comments are general in nature and there are some specialized ball valve designs that have overcome some of the general disadvantages noted here. Have a conversation with a valve specialist about your application and benefit from their experience and knowledge.

Friday, June 19, 2015

Industrial Control Valve Basics - An Introduction

Industrial process control valve
Globe Valve with Pneumatic Actuator
Courtesy Warren Controls
Valves, mechanical devices able to control flow or pressure in a process or system, are as ubiquitous as any industrial process control element. As essential components of piping systems conveying liquid, gas, vapor, or slurry, valves are a component with which almost every industrial process and control engineer will require more than entry level familiarity. They are the controlling element in almost any fluid handling system. What are some of the very basic knowledge points for specifying and selecting a control valve?

There are numerous types of valves available, including butterfly, ball, check, globe, gate, diaphragm, plug, and control valves as the most common. Particular valve types can be better suited to the medium being controlled, or have functional capabilities making them a better selection for your process application. Within each type there will be a wide range of options and features that allow for close tailoring of the complete valve assembly to match the application requirements.  Some valves can be self-operated, while others require manual operation. A pneumatic, hydraulic, or electric actuator can be employed on certain configurations to provide for remote control of the valve by a human operator or automatic controller.
General valve functions include:
  • Flow start or stop
  • Flow rate increase or reduction
  • Diversion of flow in another direction
  • Regulation of a flow or process pressure

Industrial process control valves are often classified according to their mechanical movement. Some common examples include:
  • Linear motion valves, in which the closure element moves in a straight (linear) direction to control the flow. Gate, globe, and diaphragm valves are in this category.
  • Rotary motion valves have a closure that follows an angular or circular path. Butterfly and ball valves are in this group.
  • Quarter turn valves, a subset of the rotary motion class, traverse from the open to closed state when the closure element (for example, the ball in a ball valve) is rotated through a quarter of a full turn. This type is best suited for operations calling for either fully open or closed regulation, with no need for control at points in between those two states.

Each industrial control valve application and installation will have its own set of very specific requirements. The goal of the specification and selection process should be to provide safe operation, low maintenance requirements, robust and accurate operation. A manufacturer's sales engineer can be a useful source for application and specification information and assistance.
Oil Pipeline Valve
Ball Valve Installed in Pipeline
Courtesy DHV

Tuesday, January 27, 2015

Control Valve Application Checklist

Specifying of applying an industrial control valve? Here is a comprehensive checklist to help:

PROCESS CONSIDERATIONS:
Warren Control Valve
Control Valve
  1. What is the medium to be controlled. Is it a liquid, gas, or slurry?
  2. Is it corrosive, abrasive, explosive or clean single-phase medium?
  3. What is the upstream or inlet pressure. Don’t guess – use a gauge.
  4. What is the downstream pressure when valve is closed, and when flowing?
  5. Are the Vapor pressure, viscosity or specific gravity and critical properties known?
  6. What are the inlet and outlet pipe size(s) [ May be different ] and schedule?
  7. Normal, Minimal, and Startup conditions for flow, pressures and temperatures?
  8. What impact will even a small seat leakage create when shut off?
  9. What Class is required?
  10. Is the installation in an occupied area. Noise or other hazardous considerations?
  11. What is the “fail safe” orientation? In place, closed or open?
  12. If in a fail safe orientation, is a manual readjustment to be expected?
  13. What is the ANSI Pressure Class of the pipe flanges and valves in the loop?
  14. What has been the operational history in an existing application?
  15. What material is the existing piping made of. Is it considered compatible?
  16. Is there an existing valve in place and a face-to-face dimension to match?
  17. Where will the valve be located – elevation – within a piping nightmare?
  18. What maintenance – routine or preventative is normal and expected?
  19. What are preferences for Control Valve Actuation – pneumatic or electric? WHY?
  20. Is the customer going to actuate it himself and buy a “bare stem” valve?
  21. Is the stem boss compatible with his actuator stem. Double “D” or square?
  22. Is the calculated flow velocity below limits of 100 – 125 fps for saturated steam?
  23. Is the calculated flow velocity below limits of 5 fps for liquids?
  24. Is the calculated flow velocity below limits of 250 – 400 fps for gases?
"REAL WORLD" APPLICATIONS CONSIDERATIONS:
  1. Could moving vehicles damage the valve, in a specific installed location.
  2. Might seismic forces or fires present a danger to workers.
  3. What codes may be in effect? Body pressure Code, Leakage Criteria
  4. Might workers use the valve as a stepladder when conditions dictate?
  5. Is the application a “continuously modulating” or an on / off practice?
  6. Might the process be shutdown for nights or weekends?
  7. What might result when started back up after an extended shutdown?
  8. Use your imagination, anticipate the worst, and ask more questions – more, in this case, is always better.
  9. What range air set is available for actuator or positioner?
  10. Could it allow a higher than safe pressure?
  11. Where will the user store documentation for IO&M purposes?
  12. Is routine maintenance allowed or is an annual shutdown more typical?
  13. Could moving vehicles damage the valve, in a specific installed location?
  14. Might seismic forces or fires present a danger to workers?
  15. What codes may be in effect? Body pressure Code, Leakage Criteria?
  16. Might workers use the valve as a stepladder when conditions dictate?
  17. Is the application a “continuously modulating” or an on / off practice?
  18. Might the process be shutdown for nights or weekends?
  19. What might result when started back up after an extended shutdown?
  20. Use your imagination, anticipate the worst, and ask more questions – more, in this case, is always better.
  21. What range air set is available for actuator or positioner?
  22. Could it allow a higher than safe pressure?
  23. Where will the user store documentation for IO&M purposes?
  24. Is routine maintenance allowed or is an annual shutdown more typical?
PHYSICAL AND CONFIGURATION CONSIDERATIONS:
  1. Flowing media to be controlled. Steam, Liquid or Gas?
  2. Pressures upstream and downstream, therefore the differential.
  3. Two way – modulating, or on/off. Three way diverting or mixing?
  4. Is the material abrasive, explosive, or clean?
  5. Hot or Cold water chemically treated?
  6. What are inlet and outlet pipe sizes and schedules?
  7. Maximum, Normal and Startup conditions?
  8. Leakage allowed?
  9. Valve in occupied area?
  10. Previous usage history?
  11. Pipe material of construction?
  12. Actuation Pneumatic or Electric
  13. Maintenance allowed or anticipated?
  14. IO&M storage and accessibility?
  15. Control signal – PID compatibility?
  16. Mounting restrictions?
  17. How was valve “sized?”
Checklist courtesy of Warren Controls

Please consult with a application expert before selecting or installing a control valve.

Friday, November 7, 2014

The Sliding Gate Control Valve

The sliding gate control valve is a type of high performance, variable orifice, control valve with a seat design that provides a non-turbulent, straight through flow path.
sliding gate design
Sliding Gate Design

The unique port characterization breaks the fluid flow into multiple streams creating a reduced field of energy and less turbulence. This results in greater service life, quieter operation and a control valve that performs at the highest levels possible within extreme conditions.

These types of valves can operate at temperatures around 975 degrees F and pressures of 1,450 psig. They are available in 1/2″ through 10″. These style valves are normally available in Carbon Steel and 316 Stainless Steel, and Hastelloy.

This type of control valve is used in a wide range of process engineering control applications and is excellent at controlling steam, fluids, and gases.

A variety of pneumatic and electric actuators can be mounted to the sliding gate control valve depending on location and available energy supply.

sliding gate control valve
Sliding Gate Control Valve
(courtesy of Schubert & Salzer)

Advantages of sliding gate control valves:
  • Sliding gate valves combined with with digital positioners provide excellent controllability and accuracy. 
  • Short opening & closing times, and maximum control performance, due to short stroke of sliding gate valve.
  • High control with low leakage rates & long service life.


Monday, September 22, 2014

Metal Body, Industrial Diaphragm Valves

A quick video showing the basic operation of a metal body, diaphragm valve for industrial applications.

The video illustrates how the metallic lower valve body is machined for a smooth controlled flow characteristic, and how the elastomer diaphragm is controlled by the liner movement of the valve stem. Full open, full closed, or proportional flow is controlled by the relationship of the valve diaphragm and valve body.

Metal body diaphragm valves are available in many metal alloys such as brass, cast steel, and 316 stainless steel, with many different elastomers including EPDM, PTFE and Viton.

These valves are great for inert and corrosive liquid and gaseous media, are highly resistant to chemicals, are insensitive to particulate media and offer a compact  design (ideal when space is at a premium).


Saturday, May 31, 2014

Great Flow Control Tutorial Series on YouTube

Came across a great tutorial series of flow control basics, control valve basics, check valve basics and a bunch of other stuff. The videos are from the Columbia Gorge Community College and are done by a teacher there named Jim Pytel. Here's one on Flow Control Valve basics. Enjoy.