The Swanson Flo Blog is dedicated to provide educational and new product information on process control instrumentation, control valves, and valve automation. For more information on these products, visit SwansonFlo.com or call 800-288-7926.
Happy New Year from Swanson Flo
With 2017 coming to a close, all of us at Swanson Flo wanted to reach out and send our best wishes to our customers, our vendors, and our friends! We hope that 2018 holds success and good fortune for all of you.
Industrial Valve Actuators: An Overview
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| Pneumatic Actuator (Limitorque) |
Thanks to actuators, multiple valves can be controlled in a process system in a coordinated fashion; imagine if, in a large industrial environment, engineers had to physically adjust every valve via a hand wheel or lever! While that manual arrangement may create jobs, it is, unfortunately, completely impractical from a logistical and economic perspective. Actuators enable automation to be applied to valve operation.
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| Electric Actuator (Limitorque) |
Pneumatic actuators utilize air pressure as the motive force which changes the position of a valve. Pressurized-liquid reliant devices are known as hydraulic actuators. Electric actuators, either motor driven or solenoid operated, rely on electric power to drive the valve trim into position. With controllers constantly monitoring a process, evaluating inputs, changes in valve position can be remotely controlled to provide the needed response to maintain the desired process condition.
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| Large butterfly valve with actuator. |
Thanks to their versatility and stratified uses, actuators serve as industrial keystones to, arguably, one of the most important control elements of industries around the world. Just as industries are the backbones of societies, valves are key building blocks to industrial processes, with actuators as an invaluable device ensuring both safe and precise operation.
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.
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.
Water Quality Analyzers for Ultra-pure, Industrial, and Drinking Water Systems
Waltron has been an active participant in the water chemistry and analysis field for over 100 years. The company's focus started with boiler feedwater and has expanded over many years to include online analyzers for process water in a broad range of industries.
- Power Generation
- Petrochemical
- Pulp and Paper
- Water and Wastewater
- Electronics and Semiconductor
- Environmental
- Pharmaceutical
- Copper
- Dissolved Hydrogen
- Dissolved Oxygen
- Ethylene Glycol
- Hardness
- Hydrazine
- Iron
- Oil in Water
- Phosphate
- Silica
- Sodium
Schneider Electric Foxboro Measurement and Control Product Catalog
Schneider Electric / Foxboro provides customers a complete solution - from instruments in the field to the control room - to enable customers to optimize their assets-people, equipment, plant. With a history of innovation, Foxboro Field Devices provides solutions across a wide range of industries, including Energy, Oil, Gas & Refining, Renewable Fuels, Nutrition And Life Sciences, Process Automation, Water & Wastewater.
Foxboro / Schneider Electric range of products in Measurement and Instrumentation include:
- Flow
- Level
- Pressure
- Process Liquid Analytical
- Temperature
- Control
- Data Acquisition & Configurator
- Pneumatic
- Valve Positioners
- Accutech
Visit this page on the Swanson Flo website to download your full PDF version.
You can easily specify many instruments and accessories described in this catalog. Sections covering our most popular items include all the technical data you need to know for most applications. To specify the appropriate item, simply follow the step-by-step procedure at the end of each description. Please feel free to contact Swanson Flo for help.
You can easily specify many instruments and accessories described in this catalog. Sections covering our most popular items include all the technical data you need to know for most applications. To specify the appropriate item, simply follow the step-by-step procedure at the end of each description. Please feel free to contact Swanson Flo for help.
New Product Alert: The Jordan Mark 75PTP Sliding Gate Control Valve
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| Jordan Mark 75PTP |
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.
Limitorque Actuator Product Range
Limitorque has 90 years experience providing electric actuators to safely operate automated valves that protect people and property. The products that Limitorque offer are:
- Intrusive Multi-Turn Actuators - L120 and SMB Series
- Non-Intrusive Multi-Turn Actuators - MX Series
- Non-Intrusive Quarter-Turn Electric Actuators - QX Series
- Gas Powered Actuators - LDG Direct Gas Actuator
- Hydraulic Actuators - LHS and LHH Series
- Pneumatic Actuators - LPS and LPC Series
- Multi-Turn Gearboxes - V Series and SR Series
- Quarter-Turn Gearboxes - WG Series and HBC Series
Understanding Linear, Equal Percentage, and Quick Open Control Valve Flow Curves
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| Flowserve Valtek Control Valve |
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
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| 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.
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.
Instruction Manual for Bronkhorst Mass Flow Pressure Meters and Controllers for Gases and Liquids
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| Bronkhorst MFC |
For your convenience, below is the instruction manual for mass flow meters and controllers.
Contact Swanson Flo at 800-288-7926 or visit http://www.swansonflo.com for more information on Bronkhorst products.
Solenoid Valves - How They Work
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| Solenoid valve, 2-Way, Brass (ASCO) |
Solenoid valves are used throughout many commercial, municipal, industrial, and even residential settings to manage fluid flow. What we refer to as a solenoid valve is an integrated valve and actuator. The actuator, or solenoid, operates via electric current flowing through its helix shaped coil. Energizing the coil with a control signal produces a magnetic field, which then actuates the valve mechanism. Depending on the port configuration of the valve, solenoid valves can either function as two way flow controllers or as diverters in a process system, If the valve contains two ports, then the valve is an on/off valve. If the valve contains three or more ports, then the valve directs the flow of a fluid in the process system. Thanks to their flexibility, reliability, and need for only a small amount of control power, solenoid valves are a frequently used fluid process control device.
The solenoid used in a solenoid valve functions as a converter for electrical energy, using the supplied electrical energy to produce mechanical energy. Metal or elastomeric seals on solenoid valves can be coupled with electrical interfaces, allowing for relatively easy operation by the process controller. The valves typically use a metal plug to cover up a hole, and when pressure from the process fluid is applied to the valve, the pressure difference causes the solenoid valve to be in its normal position. Instead of referring to two directions of flow, the two-way solenoid valves are named two-way because these valves contain two valve ports which the fluid uses to travel.
Three way valves, similar to the name of the two-way valve, have three fluid ports. In an application example, these ports could correspond to pressure, exhaust, and cylinder. In a pneumatic system, these would be used for compressed air supply, vent, and the actuating mechanism. Regardless of the application, the valve function is the same, connecting the inlet port to one of two outlet ports. The selection array of solenoid valves for commercial and industrial use is vast, with variants suitable for a wide range of media, pressure, temperature, and operation sequence.
Pneumatic and hydraulic systems are typical applications for solenoid valves, as are processes such HVAC, where solenoid valves help control liquid refrigerant, as well as suction and hot gas lines. Solenoid valves are a popular fluid flow control options used in processing industries.
Share your fluid control requirements and challenges with application experts, combining your own process knowledge and experience with their product application expertise to develop effective solutions.
Watch the video below for more on how solenoid valves work.
Understanding the Relationship between Hydrostatic Pressure, Density and Level
Hydrostatic pressure, or head pressure, is the force produced by a column of material. As the height of the material changes, there is proportional change in pressure. To calculate hydrostatic pressure, the density of the material is multiplied by the height of the column. The level of fluid in a column can be determined by dividing the pressure value by the density of the material.
To find pressure in a column of water, a gauge placed at the bottom of the vessel. With the water having a density of 0.0361 pounds per cubic inch, the level of the fluid is calculated by dividing the head pressure by the density of the fluid.
An example to determine the level measurement of a column of water that is 2 feet tall in diameter of 0.5 feet is solved by the following steps. The first step is measuring the weight of the vessel. Next measure the weight of the vessel with fluid. The weight of the fluid is determined by subtracting the weight of the vessel from the weight of the vessel with fluid. The volume of the fluid is then derived by dividing the fluid weight by the density of the fluid. The level of the fluid is finally calculated by dividing the volume of the fluid by the surface area.
Hydrostatic pressure can only be calculated from an open container. Within a closed vessel, or pressurized vessel, the vapor space above the column of material adds pressure, and results in inaccurate calculated values. The vessel pressure can be compensated for by using a differential pressure transmitter. This device has a high pressure side input and a low pressure side input. The high-pressure input is connected to the bottom of the tank to measure hydrostatic pressure. The low-pressure input of the differential pressure transducer is connected to the vapor space pressure. The transducer subtracts the vapor pressure from the high-pressure. Resulting is a value that represents the hydrostatic head proportional to the liquid level.
Electric Power Generation Using Coal
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| Coal Fired Power Plant |
The combustion of a fossil fuel to generate electricity can be either: 1) in a steam generating unit (also referred to simply as a “boiler”) to feed a steam turbine that, in turn, spins an electric generator: or 2) in a combustion turbine or a reciprocating internal combustion engine that directly drives the generator. Some modern power plants use a “combined cycle” electric power generation process, in which a gaseous or liquid fuel is burned in a combustion turbine that both drives electrical generators and provides heat to produce steam in a heat recovery steam generator (HRSG). The steam produced by the HRSG is then fed to a steam turbine that drives a second electric generator. The combination of using the energy released by burning a fuel to drive both a combustion turbine generator set and a stream turbine generator significantly increases the overall efficiency of the electric power generation process.
Coal is the most abundant fossil fuel in the United States and is predominately used for electric power generation. Historically, electric utilities have burned solid coal in steam generating units. However, coal can also be first gasified and then burned as a gaseous fuel. The integration of coal gasification technologies with the combined cycle electric generation process is called an integrated gasification combined cycle (IGCC) system or a “coal gasification facility”. For the remainder of this document, the term “electric generating unit” or “EGU” is used to mean a solid fuel-fired steam generating unit that serves a generator that produces electricity for sale to the electric grid.
7 Important Considerations When Applying Inline, Spring-loaded Check Valves
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| Inline Spring-loaded Check Valve (courtesy of CheckAll Valve) |
Inline, spring loaded check valves can be used in horizontal or vertical applications with proper spring selection. This is most evident in vertical flow down installations. The spring selected must be heavy enough to support the weight of the trim in addition to any column of liquid desired to be retained.
2) Elbow's, Tee's or other Flow Distorting Device's
2) Elbow's, Tee's or other Flow Distorting Device's
Inline, spring loaded check valves are best suited for use with fully developed flow. Although there are many factors affecting the achievement of fully developed flow (such as media, pipe roughness, and velocity) usually 10 pipe diameters of straight pipe immediately upstream of the valve is sufficient. This is particularly important after flow distorting devices such as elbows, tees, centrifugal pumps, etc.
3) Valve Material Selection
3) Valve Material Selection
There are many factors that influence the resistance of materials to corrosion, such as temperature, concentration, aeration, contaminants, and media interaction/reaction. Special attention must be paid to the process media and the atmosphere where inline check valves are applied. It is always recommended that an experienced application tech be consulted before installation.
4) Seat Material Selection
Several seat material options are available for inline, spring loaded check valves. An allowable leakage rate associated with the “metal-to-metal” as well as the PTFE o-ring seat, is 190 cc/min per inch of line size, when tested with air at 80 PSI. Resilient o-ring seats can provide a “bubble tight” shut-off (no visible leakage allowed at 80 PSI air).
5) Sizing and Spring Selection
4) Seat Material Selection
Several seat material options are available for inline, spring loaded check valves. An allowable leakage rate associated with the “metal-to-metal” as well as the PTFE o-ring seat, is 190 cc/min per inch of line size, when tested with air at 80 PSI. Resilient o-ring seats can provide a “bubble tight” shut-off (no visible leakage allowed at 80 PSI air).
5) Sizing and Spring Selection
It is very important to size check valves properly for optimum valve operation and service life. Sizing accuracy requires the valve be fully open, which occurs when the pressure drop across the valve reaches or exceeds three times the spring cracking pressure. Again, it is recommended that an experienced application tech be consulted for help with sizing.
6) Shock-Load Applications
6) Shock-Load Applications
Inline, spring loaded check valves are not designed for use in a shock-load environment, such as the discharge of a reciprocating air compressor. These types of applications produce excessive impact stresses which can adversely affect valve performance.
7) Fluid Quality
7) Fluid Quality
Inline, spring loaded check valves are best suited for clean liquids or gasses. Debris such as sand or fibers can prevent the valve from sealing properly or it can erode internal components or otherwise adversely affect valve travel. Any particles need to be filtered out before entering the valve.
8 Critical Control Valve Selection Criteria
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| Control Valve (Valtek) |
- Control valves are not intended to be a an isolation valve and should not be used for isolating a process.
- 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.
- 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.
- 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.
- 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.
- 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.
- Don't over-size your control valve. Control valves are frequently sized larger than needed for
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.
Control Valve
Specialized for Food/Bev
Pharmaceutical (Kammer) - 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.
Consider Flangeless Wafer Style Control Valves for Excellent Flow Control
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| Jordan Mark 75 Flangeless Wafer Style Control Valve |
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.
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.
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.
Understanding Industrial Rack and Pinion Valve Actuators
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| Basic concept of rack and pinion gear. |
Pneumatic rack and pinion actuators utilize air pressure as the motive force which changes the position of a valve. A rack and pinion actuator is comprised of two opposing pistons, each with its own gear (referred to as the "rack"). The two piston racks are set against a round pinion gear. As pressure increases against one side of each piston, each rack moves linearly against the opposite sides of the pinion gear causing rotational movement. This rotational movement is used to open and close a valve. See the animation above (provided by Wikipedia) below for a visual understanding.
This short video introduces the basic parts and operation of rack and pinion valve actuators to anyone unfamiliar with the device.
Visit http://www.swansonflo.com to learn more about industrial valves, valve actuators, and valve automation.
Pressure Instrument Calibration
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| Proper pressure instrument calibration is critically important for safety and quality. |
A deadweight tester, sometimes called a dead-test calibrator, creates accurately known pressure using precise masses and pistons of a known area. The gauge or pressure instrument is connected to the deadweight tester. The device is comprised of tubes that contain either oil or water, with a primary piston positioned above the liquid and a secondary piston across from the place where the gauge connects to the tester. A mass of a known quantity is placed atop the primary piston, which is perfectly vertical. The earth's gravitational field acts upon the mass atop the piston. The combination results in a known value being applied to the deadweight tester and subsequently allows for calibration of the gauge.
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| Deadweight tester (Ashcroft) |
Once pressure builds inside the deadweight tester, surpassing the weight of the piston, the piston will rise and float atop the oil. By rotating the mass atop the piston, the piston will rotate inside its cylinder and negate any impact from friction. Developments in technology have led to testers being equipped with hand pumps and bleed valves. The same principles applied to a deadweight tester which uses oil are applied to a pneumatic deadweight tester, where gas pressure suspends the mass atop the cylinder instead of oil or water pressure.
The manometer is another device which establishes a pressure standard to calibrate gauges. Alone, the manometer is simply a U shaped tube connecting a source of fluid pressure to the gauge being calibrated. Pressure applied to the gauge will be indicated by the corresponding heights of the fluid in the columns. If the value of the density of the liquid is a precise, known value, the aforementioned constant of the earth's gravitational field will combine with the applied pressure to permit calibration of the gauge.
Test instruments which couple with the calibration of pressure transmitters are also instrumental in ensuring correct pressure calibration. Electronic and pneumatic test instruments, along with precise air pressure calibration pumps, enable calibrating a pressure transmitter in place, in the field, or on a lab bench. These portable devices, though, require their own calibration to physical standards with referenced properties. While different devices exist for establishing pressure standards in either high or low pressure environments, the shared standard allows for varying types of instrumentation to exhibit similar performance quality and accomplish the same task.
The manometer is another device which establishes a pressure standard to calibrate gauges. Alone, the manometer is simply a U shaped tube connecting a source of fluid pressure to the gauge being calibrated. Pressure applied to the gauge will be indicated by the corresponding heights of the fluid in the columns. If the value of the density of the liquid is a precise, known value, the aforementioned constant of the earth's gravitational field will combine with the applied pressure to permit calibration of the gauge.
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| Digital Test Gauge (Ashcroft) |
Test instruments which couple with the calibration of pressure transmitters are also instrumental in ensuring correct pressure calibration. Electronic and pneumatic test instruments, along with precise air pressure calibration pumps, enable calibrating a pressure transmitter in place, in the field, or on a lab bench. These portable devices, though, require their own calibration to physical standards with referenced properties. While different devices exist for establishing pressure standards in either high or low pressure environments, the shared standard allows for varying types of instrumentation to exhibit similar performance quality and accomplish the same task.
Contact Swanson Flo for any pressure instrument repair or calibration requirement. Visit http://www.swansonflo.com or call 800-288-7926.
A Proven Actuator Ideal for Valves Requiring Rotary or Linear Movement
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| Limitorque L120 electric actuator. |
When combined with a Limitorque WG or HBC series quarter-turn gear operator, L120 actuators can also be used to control butterfly, ball and plug valves, as well as damper drives, flop gates or any other device which requires rotary movement.
L120 actuators are specified for use in petrochemical, power generation, and water and waste treatment applications where failure of a single actuator can be extremely costly … even catastrophic.
For more information on Limitorque actuators, visit Swanson Flo's website or call 800-288-7926.
For your convenience, below you will find the Limitorque L120-85 installation and operation manual.
For your convenience, below you will find the Limitorque L120-85 installation and operation manual.
What are purged impulse lines and why are they needed?
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| Diagram of a purged impulse line implementation. (image courtesy of Lessons in Industrial Instrumentation by Tony R. Kuphaldt) |
Purging a sensing line will require additional valves and devices to properly control the purge fluid flow and provide for effective maintenance or repair. Because of the increased relative complexity, a purging setup will likely be employed only in cases where other methods of maintaining clear sensor lines and proper instrument operation have been considered and rejected. The impulse line will stay free of sedimentation thanks to the purge fluid, and process fluid contamination of the sensing line is avoided.
One of the most important parts of the purged impulse line system is a restriction, implemented to prevent the pressure instrumentation from sensing the elevated pressure of the purge fluid supply instead of measuring the original process fluid. The purge valve, through which the purge fluid flows, is left partially open instead of fully open. If the restriction does not mitigate the introduction of the purge fluid on the process line, then the flow rate of the purge fluid can adversely impact the process measurement. It is essential that purge flow be regulated in a manner that does not adversely impact the measurement of actual process conditions.
A basic requirement of sensing line purge systems is that the supply of purge fluid needs to be flowing at all times. Additionally, the purge fluid supply pressure must be maintained at a level greater than the process pressure because if the pressure of the purge fluid supply drops below the process pressure, the process fluid will flow into the impulse line. The purge fluid must also not react negatively with or contaminate the process and will be continuously consumed. Generally, purge rates are kept as low as possible, mitigating purge fluid impact on the process measurement and keeping the cost low. A rotameter, which indicates visual flow of the purge fluid, is an item typically paired with purge impulse line systems, and there are many options available for use as purge fluids.
Common gases for purged impulse lines include air, nitrogen, and carbon dioxide. A purge system can be applied to both gas and liquid process systems. Share your process measurement challenges with instrumentation specialists. Combine your own process knowledge and experience with their product application expertise to develop effective solutions.
Fundamentals of Thermal Mass Flow Measurement
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| Thermal Mass Flow Meter |
The original Sage Metering Document titled "Fundamentals of Thermal Mass Flow Measurement" can be downloaded here.
Swanson Flo Performance
Specialists in valves, automation and instrumentation, Swanson Flo Performance sets the standard for process control optimization and training that maximizes plant uptime, safety and operating efficiency.
- Valve automation center
- Experienced staff of factory-certified technicians
- Responsive on-call repair and service
- Extensive OEM parts inventory
- Third party audited standards
- The region’s widest range of industry application experience
- Comprehensive multi-brand process equipment knowledge
Please take a minute to watch the video below for more information.
Self-Operating Temperature Regulators
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| Jordan Mark 80 |
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.
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.
Choosing Temperature Sensors for Industrial HVAC and Chiller Equipment
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| Sensors used in HVAC |
Reprinted with permission from Gems Sensors & Controls white paper.
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| RTD |
Assuming equivalent thermistor quality and resistance values, combining the thermistor within a housing that can be installed into HVAC or chiller equipment is what differentiates one sensor assembly from another. These fall into two basic types: exposed or enclosed thermistor housings.
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| Open sensor thermistor probe. |
Enclosed thermistors encase the thermistor inside a probe that is an integral part of the housing. These eliminate the leakage issue, but because the thermistor is actually in an air pocket surrounded by the metal or plastic housing, temperature compensation and sensor responsiveness issues are introduced.
A Recent Third Option Gems Sensors & Controls has produced a third type of housing that combines the performance of an exposed thermistor design, while providing the hermetic sealing of an enclosed sensor housing. Known as the TM-950 Series, these thermistor-based temperature sensors were designed specifically to solve long-term reliability issues in HVAC and Chiller applications.
TM-950 Series temperature sensor incorporates a unique fused-glass technique to produce a hermetically sealed the housing. Molten glass is placed inside the heated housing. As the assembly cools the metal housing shrinks, compressing the glass. In addition, the boundary surface of heated metal and glass bond at a molecular level. Two nickel-plated steel tubes are positioned pre-positioned before the glass fusing process to provide a pass through for the thermistor leads. Any of a variety of thermistors may be utilized based on the temperature sensing profile required. Once leads are passed through the steel tubes and glass, induction soldering fills the tubes completely, providing a leak-proof seal to 450 psig. The result is a sensor with the benefits of direct fluid contact incorporating the leak-proof attributes of an enclosed sensor.
For more information on selecting sensors for industrial HVAC applications and chillers visit Swansonflo.com or call 800-288-7926
Happy Fourth of July from Swanson Flo
THOMAS JEFFERSON, Declaration of Independence
A Look Inside the Cashco Ranger QCT Industrial Control Valve
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| Cashco Ranger QCT Industrial Control Valve |
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.
Lined Industrial Valves for Corrosive Service
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| Lined Plug Valves (courtesy of Flowserve Durco) |
Lined valves combine the excellent mechanical properties of metallic bodies with the corrosion resistance of fluorocarbons, such as PFA and PTFE.
Lining the intricately shaped inside surfaces of a valve is certainly an engineering challenge, especially to achieve a uniform thickness and the highest lining quality, without cavities or inclusions.
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| Lined ball and swing check valve (courtesy of Flowserve Atomac) |
This effectively prevents the lining from shearing off the body in part or being removed completely.
Ideal applications include highly corrosive applications within the chemical processing industry such as sulfuric and hydrochloric acid.
Lined valves are ideally suited for corrosive applications, requiring very reliable performance, tight shutoff, constant torque and no maintenance. These valves have gained extensive usage in many industries including power generation, pulp and paper, refineries, chemical process, pharmaceutical/bioprocessing and pollution control.
For more information on lined valves, visit Swanson Flo at http://www.swansonflo.com or call 800-288-7926.
Magnetic Flowmeters (Magmeters): Principles and Applications
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| Magnetic flowmeter (Foxboro) |
In general, magnetic flowmeters are sturdy, reliable devices able to withstand hazardous environments while returning precise measurements to operators of a wide variety of processes. The magnetic flowmeter has no moving parts. The operational principle of the device is powered by Faraday's Law, a fundamental scientific understanding which states that a voltage will be induced across any conductor moving at a right angle through a magnetic field, with the voltage being proportional to the velocity of the conductor. The principle allows for an inherently hard-to-measure quality of a substance to be expressed via the Magmeter. In a Magmeter application, the meter produces the magnetic field referred to in Faraday's Law. The conductor is the fluid. The actual measurement of a magnetic flowmeter is the induced voltage corresponding to fluid velocity. This can be used to determine volumetric flow and mass flow when combined with other measurements.
The magnetic flowmeter technology is not impacted by temperature, pressure, or density of the subject fluid. It is however, necessary to fill the entire cross section of the pipe in order to derive useful volumetric flow measurements. Faraday's Law relies on conductivity, so the fluid being measured has to be electrically conductive. Many hydrocarbons are not sufficiently conductive for a flow measurement using this method, nor are gases.
Magmeters apply Faraday's law by using two charged magnetic coils; fluid passes through the magnetic field produced by the coils. A precise measurement of the voltage generated in the fluid will be proportional to fluid velocity. The relationship between voltage and flow is theoretically a linear expression, yet some outside factors may present barriers and complications in the interaction of the instrument with the subject fluid. These complications include a higher amount of voltage in the liquid being processed, and coupling issues between the signal circuit, power source, and/or connective leads of both an inductive and capacitive nature.
In addition to salient factors such as price, accuracy, ease of use, and the size-scale of the flowmeter in relation to the fluid system, there are multiple reasons why Magmeters are the unit of choice for certain applications. They are resistant to corrosion, and can provide accurate measurement of dirty fluids - making them suitable for wastewater measurement. As mentioned, there are no moving parts in a Magmeter, keeping maintenance to a minimum. Power requirements are also low. Instruments are available in a wide range of configurations, sizes, and construction materials to accommodate various process installation requirements.
As with all process measurement instruments, proper selection, configuration, and installation are the real keys to a successful project. Share your flow measurement challenges of all types with a process measurement specialist, combining your process knowledge with their product application expertise to develop an effective solution.
The video below provides additional information about magnetic flowmeters.
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