What Are High Performance Butterfly Valves (HPBV)?

High Performance Butterfly Valve
(Pratt Industrial)

Industrial process control applications can present stringent and challenging performance requirements for the physical equipment and components that comprise the process chain. The valves employed in fluid based operations need to be resistant to the impact of extreme fluid conditions, requiring careful design and selection consideration to assure proper performance and safety levels are maintained in a predictable way.

Industrial butterfly valves intended for extreme applications are generally referred to as high performance valves (HPBV). While there are plenty of published and accepted standards for industrial valves, one does not exist to precisely define what constitutes a high performance valve.

So, how do you know when to focus valve selection activities on high performance butterfly valves, as opposed to those rated for general purpose? There are a number of basic criteria that might point you in that direction:

• Extreme media or environmental temperature or pressure
• High pressure drop operation that may cause cavitation
• Rapid or extreme changes to inlet pressure
• Certain types or amounts of solids contained in the fluid
• Corrosive media

Certainly, any of these criteria might be found in an application serviceable by a general purpose valve, but their presence should be an indicator that a closer assessment of the fluid conditions and commensurate valve requirements is in order. The key element for a process stakeholder is to recognize when conditions are contemplated that can exceed the capabilities of a general purpose valve, leading to premature failure in control performance or catastrophic failure that produces an unsafe condition. Once the possibility of an extreme or challenging condition is identified, a careful analysis of the range of operating conditions will reveal the valve performance requirements.

There are numerous manufacturers of high performance butterfly valves. Pratt Industrial manufactures high-quality resilient-seated, high performance, and triple offset butterfly valves. Construction materials include carbon steel and stainless steel. Their TE Series triple offset valve offers premium, zero-leakage seating capability even in severe service applications.

You can always get more information and discuss your special requirements with a valve specialist. They have application experience and access to technical resources that can help with selecting the right valve components to meet your severe service and high performance applications.

What Are Industrial Ball Valves?

Internal view of a ball valve
(MOGAS)

Ball valves are defined by their body style, the five major styles being: Uni-body; 3-piece; split-body; top-entry; and welded body. They are further defined by the machined hole in their ball (also known as the port); the categories being "standard port" or "full port".

On a full port valve, the port is the same size as the pipeline, resulting in a better flow profile and no restriction or pressure drop. A full ported ball valve, with better flow coefficients, comes at a higher price. In many application they are necessary because a reduction in diameter, or the resulting change in flow, can be detrimental.

The reduction in a standard port valve is one pipe size smaller than the pipe connected to the valve, resulting in restricted flow and increased velocity through the valve.

2-piece and unibody ball valves (Flo-Tite)

Standard port and full port valves are not usually recommended for throttling service due the a very
non-linear flow characteristic. Characterizing the port with a special shaped orifice can improve the valve linearity and provide good control. V-port ball valves incorporate a machined "V" in the seat around the outlet side of the valve. The "V" provides a more controllable flow pattern and is desirable when ball valves are used as control valves.

A cavity filled ball valve is used in applications where cleanliness or sanitary conditions exist. Any voids, gaps or spaces between the ball, seat and stem that allow bacteria or contaminates to accumulate are filled.  The proper cavity filler material is selected consistent with the process media, application and level of cleanliness required. Cavity fillers eliminate the spaces and voids where contaminants accumulate and provides easy "flushing" (cleaning) of the valve.

In a trunnion mounted ball valve, the valve stem is mechanically attached to the ball. Trunnion mounted valves are mostly used in applications on large diameter gas and oil pipelines and at high pressures.

Most ball valves however, are designed with a “floating ball” and not held mechanically in place by a trunnion. This allows the ball to be "pushed" slightly downstream and seal itself better against the seat. One advantage to this design is that a valve using a floating ball, and fitted with metal seats, can be used for "fire-safe" applications. This means that if the valve is subject to high temperatures, such as those presented in a fire, the "soft" part of the seat will melt away, and allow the ball to secure itself against the metal seat, and thus not allow material to pass and potentially feed the fire.

For best service life and optimum safety, please review your application with a qualified ball valve applications consultant prior to specifying an industrial ball valve.

Understanding Rack & Pinion Pneumatic Valve Actuators

Internal view of rack and pinion actuator (UniTorq)

Rack & Pinion actuators are designed for operating quarter-turn valves such as butterfly, plug, and ball valves or for actuating industrial or commercial dampers.

The rotational movement of a rack and pinion actuator is accomplished via linear motion and two gears. A circular gear, referred to a “pinion” engages the teeth of a linear gear “bar” referred to as the “rack”.

In a pneumatic actuator, pistons are attached to the rack. As air or spring power is applied the to piston, the rack is “pushed” inward or “pulled” outward. This dual direction linear movement is transferred to the rotary pinion gear providing bi-directional rotation.

Rack and Pinion Animation

Pneumatic actuators have cylinders with pistons and springs that provide the linear movement. When one side of the piston is pressurized with air, gas or oil, the pinion bearing turns in one direction. When the air, gas or oil from the pressure side is vented, a spring (spring-return actuators) may be used to rotate the pinion gear in the opposite direction. A “double acting” actuator does not use springs, instead using the air, gas or oil supply on the opposing side of the piston to turn the pinion gear in the opposite direction.

Pneumatic pneumatic rack and pinion actuators are compact and save space. They are reliable, durable and provide a good life cycle. Mechanical wear of the heads and seals are their primary disadvantage.

Most actuators are designed for 100-degree travel with clockwise and counterclockwise travel adjustment for open and closed positions. World standard ISO mounting pad are commonly available to provide ease and flexibility in direct valve installation.

Rack and Pinion Actuator (UniTorq)

NAMUR mounting dimensions on actuator pneumatic port connections and on actuator accessory holes and drive shaft are also common design features to make adding pilot valves and accessories more convenient.

Feel free to contact Piping Specialties, Inc. at www.psi-team.com or 800-223-1468 with any questions you may have about valve actuation.

Instructional Video: Inserting K-Patents Generation 2.1 SAFE-DRIVE™ Process Refractometer PR-23-SD

This video is intended for individuals installing, commissioning, operating, and/ or servicing the K-Patents Safe-DriveTM Process Refractometer PR-23-SD, generation 2 model. The purpose of this video is to provide a quick guide for the above mentioned tasks in the form of K-Patents recommended best practices.

K-Patents SAFE-DRIVE™ design allows for safe and easy insertion and retraction of the sensor under full operating pressure without having to shut down the process.

Below the video is the document "Best Practices for the Safe-DriveTM Process Refractometer PR-23-SD Generation 2" for your convenience.

For more information, visit http://www.psi-team.com or call 800-223-1468.

VIDEO

DOCUMENT

Best Practices: K-Patents Generation 2.1 SAFE-DRIVE™ Process Refractometer PR-23-SD from Piping Specialties, Inc and PSI Controls

Magnetic Flowmeters: Principles and Applications

Magnetic Flowmeter (Azbil)

Crucial aspects of process control include the ability to accurately determine qualities and quantities of materials. In terms of appraising and working with fluids (such as liquids, steam, and gases) the flowmeter is a staple tool, with the simple goal of expressing the delivery of a subject fluid in a quantified manner. Measurement of media flow velocity can be used, along with other conditions, to determine volumetric or mass flow. The magnetic flowmeter, also called a magmeter, is one of several technologies used to measure fluid flow.

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.

Understanding Guided Wave Radar Level Instruments

Guided Wave Radar (GWR)
level transmitter (Drexelbrook)

One of several technologies used for level measurement in process control is guided wave radar. A Guided Wave Radar (GWR) level transmitter combines time domain reflectometry (TDR), equivalent time sampling (ETS), and low power circuitry with a form factor that includes a wave guide extending into the contained media. TDR measures distance or level using pulses of electromagnetic energy. The pulse travels along the waveguide until it reaches the media surface and is reflected back to the unit. The speed of the pulse is known, so an accurate measure of the travel time for the signal can be processed into a distance measurement. Different media will produce a range of amplitude in the reflection, with a greater dielectric difference between air and target medium producing higher amplitude in the reflection. Industries, such as telephone, computer, and power transmission, have relied on TDR for years in order to detect and pinpoint breaks in wires or cables, making the technology more mature than it may appear by its limited timeline in level measurement applications.

ETS is used to measure the high speed, low power electromagnetic energy, and is typical when applying TDR to level measurement technology, where the signal travel distance and time are very short. The electromagnetic signals are captured by the ETS technology in nanoseconds, and are then reconstructed in the equivalent time of milliseconds. The radar scans the waveguide, collecting thousands of samples to be used in signal processing. Integrating both technologies into a single level transmitter yields an accurate and responsive instrument for process measurement.

GWR instrumentation is useful in the process control industry for its ability to measure levels in a quick, consistent way. GWR transmitters are contact radar level measurement tools, as opposed to pulsed non-contact radar transmitters that emit radar pulses through free air without a waveguide. Probes, inserted into the subject tank or vessel, serve as the waveguide for the pulsed signal. They guide the pulsed microwave vertically into the tank, providing a measure of immunity from disturbance by the tank and surrounding media. Guided wave radar technology differs from non-contact radar in a number of ways. The presence or absence of a probe is only one of them.

GWR level transmitters are used in process measurement applications throughout many industries, such as food and beverage. Tanks, pumps, and piping systems for both storage and transport can utilize GWR to continuously monitor levels. Other vessels, such as reduction, forming, mixing, heating, cooking, and cooling, can utilize GWR for similar reasons. Additionally, other stages of food and beverage manufacturing, such as centrifugation and decontamination, can be good fits for GWR technology. Guided wave radarís previous applicability in industries aside from liquid processing and implementation in a wide range of process settings show the flexibility and reliability of GWR technology.

Selecting the best level measurement technology for an application can be a challenge. Share your project requirements and concerns with a process instrumentation specialist, combining your own process knowledge and experience with their product application expertise to develop effective solutions.

7 Reason to Choose Full Flanged, Full Port, Wafer Style Valves

Abstracted from an article by Robert Donnelly of Flo-Tite.

1. Space Savings - Shorter in width than a standard flanged ball valve, the wafer-style ball valve

   

   Flo-Tite Kompact Series Valve

   is ideal for skid systems or any application where space is an issue. Ideal for under tanks too.
2. Lower Torques - With less torque than other con­ventional full-port valves, the wafer valve can be automated by smaller actuators with smaller universal mounting kits.
3. Less Weight - The wafer valve weigh­s about 30% less than full-port flanged ball valves.
4. One Piece Body - If steam jacketing is required, the jackets cost much less than two-piece bolt-on types. 
5. Pocket-less Design - Many process control engineers will not use ball valves because of the dead space behind the valve ball. The pocket-less design of the wafer valve eliminates that concern.
6. Easier to modify flanges to meet standards - When equipment made in Europe is sent to U.S. there is often a need to tran­sition from the DIN flange to an ANSI interface to install the equip­ment here. With the wafer valve, it is relatively easy to modify the flanges to mate.
7. Tapped flanges - Adds to the ease of installation or maintenance as one side of the piping can be re­ moved while the valve is still under pressure.

For more information on Full Flanged, Full Port, Wafer Style Valves contact Piping Specialties, Inc by calling 800-223-1468 or visit http://www.psi-team.com.