Advanced Cell Bypass for Variable Frequency Drives (VFDs)

Advanced cell bypass is patented technology at the Siemens Robicon drive. It allows the drive to continue operating in the unlikely event at the cell fault.

This feature is available on all Siemens Robicon drives. The unique perfect harmony topology makes it all possible.

When a drive is equipped with this feature a contact is present on the output if each other power cells. In the event of a fault the contact closes and isolates the output to the power cell.

With multiple power cells connected in series, the loss of one power cell leaves the remaining cells active, which allows the VFD to continue operating at a voltage a at least 80 percent, or up to 92 percent speed on a centrifugal load. This serial cell configuration is central to the bypass feature.

Watch the video below to learn more abut this technology.

Using Pneumatic Volume Boosters on Valve Systems

pneumatic volume booster
Pneumatic volume booster
A pneumatic air volume booster reproduces a low flow control signal with a higher regulated flow output pressure. It uses an unregulated input pressure to maintain a regulated output pressure under flowing and non-flowing conditions.

The regulated output of a pneumatic air volume booster can be any of the following:

      • A direct reproduction of the pneumatic control signal
      • A multiple of the pneumatic control signal
      • A fraction of the pneumatic control signal

Volume boosters are also used in conjunction with valve positioners on large control valve actuators to provide faster response than possible with the valve positioner alone. Deadband within the volume booster allows the positioner to make small incremental valve positioner changes in a highly stable manor without activating the volume booster valves.

The following video provides and in-depth understanding on how to use pneumatic volume boosters with valve actuator systems and how to optimize performance.

How Self Regulating Heating Cable Works

self regulating heat trace
Self regulating heat trace cable.
Self regulation heating cable in used in many industrial and commercial applications to maintain temperatures in pipes. vessels, and tanks. Whereas constant wattage cables produces the same power output irrespective of process temperature, self regulating cable automatically adjusts the power output depending on process temperature.

For example, during a startup or when ambient conditions are cold, the fluid in the pipe may require more heating power to maintain the desired process temperature. In this situation, the self regulating cable will produce a higher wattage per foot to heat the pipe. As the process media temperature increases, then need for that amount of input power decreases, and the self regulating cable automatically cuts the power output accordingly.

This video, courtesy of Raychem, provides a short but informative understanding of how self regulating heat tracing cable (sometimes referred to as "heat tape") works.

For more information, contact:
Instrument Specialties Inc.
3885 St. Johns Parkway
Sanford, FL 32771
phone 407.324.7800
fax 407.324.1104

Spectroscopic Analysis Systems for Continuous Inline Measurement

1) Analyzer Unit, 2) Optical window
3) Medium (e.g. milk)
Light of varying wavelengths is coupled into the medium using LEDs and laser diodes, which in turn measures various contents of a product, such as protein, fat, free fatty acids, lactose and the COD value. All while still inline (in the pipeline during the process), with the utmost precision. The values of up to four different optical effects are calculated and converted to highly accurate measurements.

Wave Matrix - Four Optical Analytical Principles

The analyzer uses several light sources and works in the UV, VIS, NIR and IR spectral ranges. The light waves are coupled into the medium via an optical window and measured using appropriate sensor elements, depending on the analytical process.

The analyzer uses four measuring principles to synchronously measure the transmission, scattering, fluorescence and refraction values of the light. Depending on the application, the analyzer works synchronously with a combination of up to 12 different wavelengths of between 200 and 4000 nm. The multitude of raw measured values are fed into a mathematical

model which determines, for example, the protein and fat content.

Accuracy and Repeatability

Thanks to the elimination of moving parts, the measuring velocity,  long-term accuracy and repeatability were significantly improved upon compared to typical bypass devices. In addition, compared to laboratory measurements, using the analyzer eliminates potential error sources that may be caused by the taking, transporting and preparation of samples.

Hygienic process connection

The analyzer is connected to the process without contact via an optical window in an easy to clean via (SIP/CIP) and FDA-compliant standard housing.

Water Cooling and Air Flushing

Integrated water cooling is recommended to ensure optimal cooling at higher ambient temperatures and when measuring hot media. Air flushing effectively prevents condensation on the optical window at low process temperatures.

Recalibration and Maintenance

Compared to typical laboratory and bypass devices, no daily recalibrations are necessary when operating the analyzer. As there are no moving parts, high long-term stability and thus minimal maintenance is achieved.

If, however, it does prove necessary to check a reading, this can be done easily with the integrated sampling valve and by entering reference values determined in the laboratory directly into the analyzer.

Compact and Flexible

The compact operating unit of the analyzer is very flexible and can be installed anywhere thanks to a serial interface - either in its own stainless steel housing or into a control cabinet on site. The measured values and status information can be read off this unit and sent to the automation system.

For more information, visit OPTIQUAD at Instrument Specialties

On the Bench. A Look Inside the Valtek Mark One Globe Control Valve

Valtek Mark One
Glove Control Valve
The video below provides the viewer with a look inside the Valtek Mark One control valve and identifies its major components.

The 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.

Advanced Laser Doppler Technology for Non-Contacting Area Velocity Flow Measurement

Laser Doppler Velocity
Laser Doppler Technology
for Non-Contacting Area
Velocity Flow Measurement
(by Teledyne ISCO)
A new velocity sensor remotely measures flow in open channels with non-contact Laser Doppler Velocity technology and non-contact Ultrasonic Level technology. The sensor uses advanced technology to measure velocity with a laser beam at single or multiple points below the surface of the wastewater stream.

An ultrasonic level sensor is used to measure the level and then determines a sub-surface point to measure velocity. The sensor then focuses its laser beam at this point and measures the frequency shift of the returned light.

This sensor is ideal for a broad range of wastewater monitoring applications and is compatible with readily available flow meters.

With optional continuous wave Doppler Ultrasonic Area Velocity technology flow measurement continues without interruption even while submerged.

With a specially designed mounting bracket the sensor can be deployed and removed from street level,  avoiding the risk and expense of confined space entry. A variety of communication options enable programming and data retrieval from a remote location as well. Built-in diagnostic tools simplify installation, maintenance, and advanced communication options reduce site visits.

The sensor provides excellent system versatility across a wide variety of industrial applications to manhole installations, with many configuration options providing the flexibility to measure flow in most open channel applications.

Depending on your application needs, the device can be programmed to take velocity measurements at single or multiple points below the water's surface, producing an accurate mean velocity reading.

In applications where the level measurement point of the built-in ultrasonic and the measurement point of the laser velocity are of different elevations, such as a freefalling outfall or drop manhole, the remote ultrasonic option can be used so that both measurement points reference the same elevation.

During submerged conditions, the optional bottom-mounted area velocity sensor seamlessly takes over the flow rate measurement. The sensor provides ultrasonic Doppler velocity measurement and Differential Pressure level measurement. This option measures flow in the pipe/channel. By measuring velocity over a large area, the ultrasonic Doppler technology provides more accurate flow measurement during submerged conditions.

For redundant flow measurement at critical monitoring sites, a unique flexibility is added by an optional sensor which is mounted at the bottom of the pipe. This sensor provides redundant velocity, level, and flow data from the same site as the device.

Following initial installation and adjustment, the sensor can be installed or removed as needed without manhole entry in most situations, using the optional sensor retrieval arm to grasp the handle.

The handle's simple yet effective locking mechanism holds the sensor securely in place, and is easy to engage and release from above ground.

For more information contact:

Instrument Specialties Inc.
3885 St. Johns Parkway
Sanford, FL 32771
phone 407.324.7800
fax 407.324.1104

A Compact, Rugged and Explosion Proof Industrial Pressure Switch

Mini Hermet
Mini Hermet
Need a robust, explosion proof pressure switch with a small footprint? The SOR "Mini Hermet" is your answer. This pressure switch is ideally suited for a variety of process applications in hazardous locations and hostile environments where stainless steel exterior parts are required and where space is limited. Basic models with standard wetted parts are normally suitable for air, oil, water and non-corrosive process fluids.

The pressure sensing assembly is similar to a conventional pressure switch. The main difference is that the switching element assembly is hermetically sealed in an explosion proof steel capsule. Switching elements are SPDT or DPDT.

The pressure sensing element is a force-balance, piston-actuated assembly. The sensing element is sealed by a flexible diaphragm and a static o-ring. There are only three wetted parts in this arrangement: a pressure port, a diaphragm and an o-ring. A wide selection of wetted parts materials for media compatibility and containment are available.

For more information contact:

Instrument Specialties Inc.
3885 St. Johns Parkway
Sanford, FL 32771
phone 407.324.7800
fax 407.324.1104

Thermal Mass Flow Meters

Brooks SLA Thermal Mass Flow
Thermal Mass Flow Meter
(courtesy of Brooks Instrument)
The basic operation of a thermal mass flow meters is to measure flow by introducing heat into the flow stream and measuring the heat dissipation between one or more temperature sensors.

Thermal mass flow meters are very popular for several reasons. They have no moving parts, have a fairly unobstructed flow path, are accurate over a wide range of flow rates, calculate mass flow rather than volume, measure flow in large or small piping systems, and do not need temperature or pressure compensation. While most thermal flow meters are used to measure flowing gas, some also measure flowing liquids.

Thermal mass flow meters are cost effective and accurate making it an excellent choice for a wide variety of gas flow applications.

Basic Lesson on Flow Control Valves

For anyone interested in flow control basics, control valve basics, check valve basics and many other technical topics, videos are available on YouTube from the Columbia Gorge Community College. The teacher's name is Jim Pytel and he does an excellent job. Here's a video tutorial Flow Control Valve basics.

Welcome to the Process Instrumentation and Control Blog of Florida

process control blog
Process Control Professionals
We're building this blog to provide people interested in process control instrumentation, industrial valves, measurement and control a place to learn interesting applications, products, and basic knowledge.

The markets we are attempting to connect with are the powergen industry, mining, water and wastewater treatment, agricultural, chemical, food & beverage, pharmaceutical and OEMs.

We'll do our best to provide weekly posts to keep the blog fresh and informative, and a place you'll want to check back with regularly.

The world of industrial control is changing rapidly in the United States, partially due to rapidly changing technology, or environmental and legislative pressures. We hope to provide helpful information, based on current realities, that will help solve real world process control problems.