Showing posts with label Control Valve. Show all posts
Showing posts with label Control Valve. Show all posts

Saturday, September 29, 2018

The Basics of Control Valve Actuators

Flowserve Valtek Control Valve
Control Valve
(Flowserve Valtek)
Understanding control valve operation is very important to for anyone considering a career in process engineering, in plant maintenance, or process design engineering.

Control valve actuators control fluid in a pipe by varying the orifice size through which the fluid flows. Control valves contain two major components: the valve body and the valve actuator. The valve body provides the fluid connections and a movable restrictor comprised of a valve stem and plug that is in contact with the fluid that varies the flow. The valve actuator is the component that physically moves the restrictor to vary the fluid flow.

The video below introduces the viewer to basic control valve operation concepts and the basic types of actuators.

Wednesday, June 20, 2018

A Peek Inside a Valtek Mark One Control Valve with Piston Actuator

Valtek Mark One Control ValveThe video below provides a look inside the Flowserve Valtek Mark One control valve and identifies its major components.

The Flowserve Valtek® Mark One globe control valve is designed for liquid and gaseous services, and for permitting easy, fast and inexpensive maintenance.

The spring-cylinder actuated Mark One valve provides stiffness and maintains high positioning accuracy, repeatability, controlled high speed, and faithful response. The Mark One valve handles up to 150 psig supply air and has the thrust to shut off against much higher fluid pressures.

The Mark One valve is designed so the spring, supply air pressure and fluid pressure itself combine to produce exceptionally tight shutoff. A self-aligning seat ring further enhances the shutoff capability of the valve.

https://swansonflo.com
800-288-7926

Friday, May 25, 2018

Flowserve Control Valve Product Guide (Valtek, Kammer)

Flowserve Control Valve
Flowserve Control Valve
Flowserve general service control valves combine platform standardization, high performance, and simplified maintenance to deliver a lower total cost of ownership.

Flowserve delivers a broad range of general service control valves – linear and rotary – with pressure ratings of ANSI Class 150 to 4500/PN 10 to PN 640. These high-performance control valves offer greater reliability, precision control, and flow capacity, with significantly reduced cavitation, flashing, and noise. Quality production ensures increased process yield and throughput.

Because Flowserve general service control valves are constructed on global platforms using standardized parts and components, up-front engineering is held to a minimum. Simplified operation, maintenance, and service further ensure lower total cost of ownership.

Wednesday, March 7, 2018

Disassembly, Repair, and Rebuild of the Jordan Mark 78 Control Valve

Jordan Mark 78 Control Valve
The Jordan Mark 78 pneumatic control valve is designed for accurate performance and simplified maintenance. This versatile product can be used on a variety of applications, including viscous/corrosive liquids, process gases or steam in process or utility service.
  • Shutoff: ANSI Class IV or VI
  • Sizes: 1/2" – 2" (DN15 – DN50)
  • End Connections: Threaded, Flanged, Socket Weld, Butt-Weld
  • Body Materials: Bronze, Carbon Steel, Stainless Steel
  • Cv (Kv): up to 50 (up to 43)
  • Trim Materials: Stainless Steel, Monel, Hastelloy C, Alloy 20
  • Seat: ANSI Class IV (Hard Seat); ANSI Class VI Teflon (Soft Seat)
  • Control Ranges: 3-15 psi, 6-30 psi or split ranges (0,2-1,0 bar, 0,4-2,1 bar)
The video below provides a detailed demonstration of how to disassemble, repair, and rebuild the Mark 78 control valve.

800-288-7926 

Saturday, January 27, 2018

Flowserve Valtek MaxFlo 4 Eccentric Rotary Plug Control Valve

Valtek MaxFlo 4 Eccentric Rotary Plug Control Valve
The Flowserve Valtek MaxFlo 4 control valve is a high performance eccentric rotary plug valve designed for the process industry. It features a large capacity, standard hardened trim and superior shaft blow-out protection.

This valve is available in sizes 1 through 12 inches, ASME Class 150, 300 and 600 as well as DIN PN 10, PN16, PN 25, PN40 and PN63. An optional ISA 75.08.01 or DIN EN 558 series 1 long-pattern body makes this valve an easy drop-in replacement for a globe control valve. 

Founded in 1960, Swanson Flo has long maintained our position as an industry leader in process automation with unmatched project success leveraging industry preferred products and services. 

800-288-7926

Tuesday, December 19, 2017

Visual Demonstration of Cavitation and its Adverse Effects on Control Valves and Pumps

Fluid passing through a control valve experiences changes in velocity as it enters the narrow constriction of the valve trim (increasing velocity) then enters the widening area of the valve body downstream of the trim (decreasing velocity). These changes in velocity result in the fluid molecules’ kinetic energies changing as well. In order that energy be conserved in a moving fluid stream, any increase in kinetic energy due to increased velocity must be accompanied by a complementary decrease in potential energy, usually in the form of fluid pressure. This means the fluid’s pressure will fall at the point of maximum constriction in the valve (the vena contracta, at the point where the trim throttles the flow) and rise again (or recover) downstream of the trim:


If fluid being throttled is a liquid, and the pressure at the vena contracta is less than the vapor pressure of that liquid at the flowing temperature, the liquid will spontaneously boil. This is the phenomenon of flashing. If, however, the pressure recovers to a point greater than the vapor pressure of the liquid, the vapor will re-condense back into liquid again. This is called cavitation.

As destructive as flashing is to a control valve, cavitation is worse. When vapor bubbles re-condense into liquid they often do so asymmetrically, one side of the bubble collapsing before the rest of the bubble. This has the effect of translating the kinetic energy of the bubble’s collapse into a high-speed “jet” of liquid in the direction of the asymmetrical collapse. These liquid “microjets” have been experimentally measured at speeds up to 100 meters per second (over 320 feet per second). What is more, the pressure applied to the surface of control valve components in the path of these microjets is intense. Each microjet strikes the valve component surface over a very small surface area, resulting in a very high pressure (P = F/A ) applied to that small area. Pressure estimates as high as 1500 newtons per square millimeter (1.5 giga-pascals, or about 220000 PSI!) have been calculated for cavitating control valve applications involving water.

Monday, November 27, 2017

New Product Alert: The Jordan Mark 75PTP Sliding Gate Control Valve

Jordan Mark 75PTP
Jordan Mark 75PTP
The Jordan Mark 75PTP is a Mark 75 wafer style control valve with an 80mm (1" - 2") Stainless Steel Piston Actuator. The Gemu cPOS Smart Positioner is standard and required for control applications. For on/off service, the valve may supplied without a positioner. JVCV Should be used for sizing selection.

The Mark 75PTP provides great capacity in a com-pact wafer style body. A 2" Mark 75PTP provides 72 Cv (62 Kv). (Refer to Cv Capacity Charts for information concerning all line sizes).

The Mark 75PTP features a 'T' slot design connection to the disc. This connection allows for quick and easy reversing of functions. Instead of having to go into the actuator to change action, all that is needed in a Mark 75PTP is to rotate the seats 180°. With this simple rotation, the valve can go from reverse acting to direct acting (or vice versa).The stroke length of the Mark 75PTP is a slightly longer stroke than standard sliding gate valves. This longer stroke enables better turndown. Combined with the capacity of the Mark 75PTP, the in-creased turndown makes for a great control valve.





Wednesday, November 8, 2017

Understanding Linear, Equal Percentage, and Quick Open Control Valve Flow Curves

Flowserve Valtek Control Valve
Flowserve Valtek Control Valve
Flow characteristics, the relationship between flow coefficient and valve stroke, has been a subject of considerable debate. Many valve types, such as butterfly, eccentric disk and ball valves, have an inherent characteristic which cannot be changed (except with characterizable positioner cams). Flow characteristics of globe valves can be determined by the shape of the plug head.

The three most common types of flow characteristics are quick opening, equal percentage and linear. The figure below shows the ideal characteristic curve for each. These characteristics can be approximated by contouring the plug. However, inasmuch as there are body effects and other uncontrollable factors, plus the need for maximizing the flow capacity for a particular valve, the real curves often deviate considerably from these ideals. When a constant pressure drop is maintained across the valve, the characteristic of the valve alone controls the flow; this characteristic is referred to as the “inherent flow characteristic.” “Installed characteristics” include both the valve and pipeline effects. The difference can best be understood by examining an entire system.

Equal Percentage
Control valve flow curves
Control valve flow curves.


Equal percentage is the characteristic most commonly used in process control. The change in flow per unit of valve stroke is directly proportional to the flow occurring just before the change is made. While the flow characteristic of the valve itself may be equal percentage, most control loops will produce an installed characteristic approaching linear when the overall system pressure drop is large relative to that across the valve.

Linear

An inherently linear characteristic produces equal changes in flow per unit of valve stroke regardless of plug position. Linear plugs are used on those systems where the valve pressure drop is a major portion of the total system pressure drop.

Quick Open

Quick open plugs are used for on-off applications designed to produce maximum flow quickly.

This information provided courtesy of Flowserve Valtek. Share your control valve requirements and challenges with a valve specialist, combining your own process knowledge and experience with their product application expertise to develop effective solutions.

Sunday, September 10, 2017

8 Critical Control Valve Selection Criteria

Control Valve (Valtek)
Control Valve (Valtek)
Choosing an improperly applied sized or improperly sized control valve can have serious consequences on operation, productivity and most important, safety. Here is a quick checklist of basics that need to be considered:
  1. Control valves are not intended to be a an isolation valve and should not be used for isolating a process. 
  2. Always carefully select the correct materials of construction. Take into consideration the parts of the valve that comes in to contact with the process media such as the valve body, the seat and any other "wetted" parts. Consider the operating pressure and operating temperature the control valve will see. Finally, also consider the ambient atmosphere and any corrosives that can occur and effect the exterior of the valve. 
  3. Put your flow sensor 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.
  4. Factor in the degree of control you need and make sure your valve is mechanically capable. 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. 
  5. Consider stiction. The tendency for valves that have had very limited travel, or that haven't moved at all, to "stick" is referred to as stiction. It typically is caused by the valves packing glands, seats or the pressure exerted against the disk. To overcome stiction, additional force needs to be applied by the actuator, which can lead to overshoot and poor control.
  6. 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 that replaced the old fashioned trial and error loop tuning method.
  7. Don't over-size your control valve. Control valves are frequently sized larger than needed for
    Control Valve Specialized Kammer
    Control Valve
    Specialized for Food/Bev
    Pharmaceutical (Kammer)
    the flow loop they control. If the control valve is too large, only a small percentage of travel is used (because a small change in valve position has a large effect on flow), which in turn makes the valve hunt. This causes excessive wear. Try to always size a control valve at about 70%-90% of travel.
  8. Think about the type of control valve you are using and its inherent flow characteristic. Different types of valve, and their disks, have very different flow characteristics (or profiles). 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 have very 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 electing a control valve. You should always discuss your application with an experienced application expert before making your final selection.

Tuesday, September 5, 2017

Consider Flangeless Wafer Style Control Valves for Excellent Flow Control

Mark 75 Flangeless Wafer Style Control Valve
Jordan Mark 75 Flangeless
Wafer Style Control Valve
Valves are essential to industries which constitute the backbone of the modern world. The prevalence of valves in engineering, mechanics, and science demands that each individual valve performs to a certain standard.

One category of valves are "control valves". These can be linearly operated, or rotary operated. There are many types of control valves, such as gate, globe, ball, butterfly, and plug. All of these valve types have some sort of ball, plug, gate, or disc that throttles the flow as the valve opens and closes. Some valve designs are better suited to uniformly control flow, such as gate valves or valves with specially machined disks. This post is about the Jordan Mark 75, a valve that uses a unique sliding gate design.

According to Wikipedia, "A control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller. This enables the direct control of flow rate and the consequential control of process quantities such as pressure, temperature, and liquid level."

The Mark 75 Series control valve is a industrial process control valve manufactured by Jordan Valve. It's design benefits include the sliding gate seat design, low weight, and compact wafer style body. The Mark 75 offers an incredible pricing advantage in the market place due to its wafer style body.

The stroke length of the Mark 75 is a slightly longer stroke than standard sliding gate valves. This longer stroke enables better turndown. Combined with the capacity of the Mark 75, the increased turndown makes for a great control valve.

Please watch the video below, and see the specification sheet at the bottom for further details. For more information about this valve, or any Jordan Valve product, contact Swanson Flo at 800-288-7926 or visit http://www.swansonflo.com.


Wednesday, July 12, 2017

Self-Operating Temperature Regulators

Jordan Mark 80
Jordan Mark 80
In process control applications, exceedingly close control with PID loops is not always necessary. There can also be instances where location or operational circumstance calls for temperature control, but not necessarily under the control of a centralized system. Self operated mechanical temperature regulators, with their reliable and simple operating scheme, can be well suited for these applications.

Self operated temperature regulators are basically valves with self contained actuation controlled by a filled system, or bulb. The valve portion of the assembly controls the flow of a fluid which impacts the process temperature. The process temperature is measured by a fluid filled bulb, connected via a capillary to a chamber containing a diaphragm. As the temperature of the process changes, the fluid in the bulb expands or contracts, changing the fluid pressure on the diaphragm. Pressure on the diaphragm causes movement, which is linked to the sliding gate trim of the valve, thus adjusting fluid flow. A spring provides a counteractive force on the diaphragm and allows for setpoint adjustment.

The self contained assembly requires no external power source to operate and requires little maintenance. Proper selection of line size, capillary length, bulb type, and temperature range are key elements in getting the right valve for the job. Application temperature ranges from -20 to +450 degrees Fahrenheit.

The Mark 80 Series Temperature Regulator features the advanced sliding gate seat technology pioneered by Jordan Valve. Using the Jordan Valve sliding gate seat technology, the Mark 80 temperature regulators have the signature straight-through flow, short-stroke that is 1/3 of a globe-style valve, quiet operation and tight shutoff. The Jordan Valve Mark 80 has high rangeability and extremely accurate regulation. The proprietary Jorcote seat material is extremely hard (@RC85) with a low coefficient of friction that delivers outstanding performance and long service life.
Share your temperature control and fluid flow challenges with product application specialists, combining you own process expertise with their product application know-how to develop the most effective solutions.

You can see all the details in the datasheet included below. For more information contact Swanson Flo by calling 800-288-7926 or visit http://www.swansonflo.com.

Tuesday, June 27, 2017

A Look Inside the Cashco Ranger QCT Industrial Control Valve

Cashco Ranger QCT Industrial Control Valve
Cashco Ranger QCT
Industrial Control Valve
The Cashco Ranger is one of the most popular industrial control valves on the market. It is the most versatile, adaptable, and easily maintainable valve ever produced. No other valve is more user friendly.

The Ranger offers over 6 different trim combinations. Trim can easily be changed in less than 5 minutes without disturbing the packing, actuator, or positioner calibration. The service area is a thread-less design, which resists corrosion or collection of chemical deposits.

A selection of 3 body materials with a broad temperature range from -325°F to +750°F makes the Ranger adaptable for use in steam, heat transfer fluids, slurries, gases, liquids, and cryogenic applications. The Ranger’s unique dual seating design provides both Class VI and backup Class IV seat leakage. And the standard patented live-loaded packing system lets you check and adjust packing without the need for specialized tools or complicated procedures.

Check out the video below for a detailed look. For more information, visit Swanson Flo at http://www.swansonflo.com or call (510) 274-1990.

Friday, May 12, 2017

The Advantages of the Sliding Gate Control Valve Seat in Process Control

Sliding Gate Control Valve Seat
Sliding Gate Control Valve Seat (Jordan)
Fluid flow control in a process can present a number of challenges, large and small. In addition to selecting a properly sized control valve, your choice of trim design can contribute noticeably to overall positive performance. One candidate for fluid flow control is the sliding gate valve.

The trim of a sliding gate valve essentially consists of a fixed disc and a movable plate installed directly in the flow path. The disc and plate have precisely located and sized perforations, slots, or other openings. The valve actuation mechanism slides the plate across the face of the disc, progressively changing the alignment of the openings in the plate and fixed disc. This type of design can bring some benefits to the process and user:

  • Short stroke length provides fast response, reduces wear on packing and diaphragm, allows for a compact installed assembly
  • Straight-through flow pattern reduces turbulence, noise, erosion, valve chatter, and cavitation
  • Ease of maintenance, with fewer trim components that are easily changed
  • Self cleaning, self lapping seats

The video below provides a clear illustration of how the sliding gate valve trim works, through animation and exploded views of the valve components. Share your fluid flow control challenges with a valve specialist and combine your process expertise with their product application knowledge for an effective solution.

Monday, April 17, 2017

Flowserve Valtek Valve Automation

The video below highlights several Swanson Flo automated Valtek control valves. Included in these systems are Valtek ShearStream segmented ball valves, Valtek Valdisk BX butterfly valves, Logix positioners, Valtek VR piston actuators, and StoneL Axiom valve monitors.


Swanson Flo is a premier valve and valve automation supplier located in Plymouth, MN with warehouse and fabrication facilities in Addison, IL, Indianapolis, IN and Menomonee Falls, WI.

Visit Swanson Flo at http://www.swansonflo.com or call 800-288-7926 with any valve automation project.

Saturday, March 18, 2017

Understanding Control Valves: The Flowserve Valtek Mark One

Control valves are an integral part of many process control loops. Understanding their basic operation is important for any process control professional. The following video demonstrates the reassembly of the Flowserve Valtek Mark One control valve and introduces the viewer to a control valve's main components.

There are a variety of styles of control valves. A globe control valve is a specific type of valve used for regulating flow in a pipe. The design includes a movable plug, connected to a stem, which can be moved linearly to close or open the valve. Globe control valves are referred to as “linear” valves because of this movement to open and close is directed by a piston type, linear movement actuator. Generally, globe control valves provide better overall flow control than quarter-turn valves due to the design of their flow path.

For more information, a Valtek Mark One specification sheet is also included with this post.