Showing posts with label Maryland. Show all posts
Showing posts with label Maryland. Show all posts

Tuesday, March 13, 2018

The Ideal Flow Monitoring System for a Drinking Water Supply Network

The ideal drinking water flow monitoring system.
Wouldn't it be great if you had a closely woven system of measuring points that monitor flow rates in the drinking water supply network as seamlessly as possible and leaks and hydrological problem zones would be detected and corrected as quickly as possible?

Unfortunately the reality looks somewhat different. Installation of conventional flow measuring points in a drinking water supply network incurs high costs and an enormous amount of effort to maintain.


FLEXIM is a technology leader in the field of non-invasive flow measurement with clamp-on ultrasonic technology. FLEXUS clamp-on ultrasonic systems measure according to the transit time difference method. Since the transducers are mounted on the outside of the pipe no interventions in the pipeline system are necessary. the drift free and long-term stable acoustic measuring method detects even the smallest flows, even those that lie below the response threshold of conventional flow meters. Therefore, fluxes is the ideal instrument for monitoring minimum flow rates at night, and thus the key to effective consumption and leakage monitoring.

With FLEXUS, a flow measuring point can be conveniently setup within half a working day without supply interruptions with out affecting traffic, and without a heavy lifting device.  For the installation of the ultrasonic measuring system, only temporary access to the pipe has to be created.  The service engineer first checks the pipe dimensions. Sturdy mounting devices made of stainless steel ensure that the flow transducers are permanently stable when installed. Even on the transducers themselves, nothing can break. The cable and sensor are firmly connected. No plug can come loose. Water or dirt cannot penetrate anywhere. The ultrasonic transducers have IP68 protection and can operate continuously underwater. Coupling pads, made of elastic plastic, ensure permanent optimal acoustic coupling to the pipe without any wear. Thanks to their unique internal temperature compensation, FLEXIM transducers do not show any drift during temperature fluctuations. Setup of the measuring point on the pipe is completed by positioning and fixing the ultrasonic transducers. Now only the connection to the measuring transmitter, housed in the switch cabinet, has to be created. The calibration data of carefully paired and calibrated transducers are stored on one chip and are automatically transferred to the measuring transmitter. A zero point calibration on site is not necessary. Where nothing flows, FLEXUS reliably measures zero.

Measurement in Progress

The measuring results are either transmitted by cable or wirelessly via GSM to the process control system. Practical self-diagnosis functions allow for safe evaluation of the measurement quality. Done. Now the measuring point can be refilled underground since the pipe line remained completely intact. There was no need to flush the pipe and no need for the final leak test. In the office, the measured values can be visualized and evaluated on a computer.

Sunday, February 25, 2018

Bently Nevada 3500 Series Machinery Monitoring System Datasheet

Bently Nevada 3500 Series Machinery Monitoring System
Machine condition monitoring combines hardware, software, and service and support – providing a broad, connected view of your operations. Together, they enable your plant to mitigate risk, boost safety, and reduce maintenance costs, while improving equipment reliability, uptime, and efficiency.

Hardware monitoring systems and sensors protect your equipment and collect rich condition monitoring and diagnostic data for analysis. Condition monitoring and diagnostics software connects real-time and historical data from production equipment to help you anticipate failure before it occurs. With scalable deployment and ongoing support service offerings, you can ensure that you’re maximizing the value of your condition monitoring program.

The Bently Nevada 3500 Monitoring System provides continuous, online monitoring suitable for machinery protection and asset condition monitoring applications. It represents our most capable and flexible system in a traditional rack-based design and offers numerous features and advantages not provided in other systems.

Download a PDF version of the Bently Nevada 3500 System datasheet here, or quickly review the embedded document below.

For more information, contact Flow-Tech in Maryland by calling 410-666-3200, in Virginia by calling 804-752-3450, or by visiting

Friday, February 16, 2018

Campus Metering: Advantages of Using V-Cone for Measuring Chilled Water & Steam in Hospitals, Universities, and Institutions

McCrometer's V-Cone
Typical diagram of V-Cone installation.
(Click for larger view).
McCrometer's V-Cone® Flow Meter is an advanced differential pressure instrument, which is ideal for use with liquid, steam or gas media in rugged conditions where accuracy, low maintenance and cost are important. The V-Cone is especially useful in tight-fit and retrofit installations. 

In most instances the use of V-Cones associated with chillers for chilled water in large institutional users is a matter of space, accuracy, and turndown. The V-Cone needs very little upstream and downstream piping requirements, allowing it to be used in spaces where other meters cannot be used, or to replace existing flowmeters that never proved accurate because of space limitations. 

In many large universities and other facilities, such as hospitals and airports, across the U.S., the reason for initial interest and subsequent purchases of V-Cones to measure Chilled Water was to fit within the confines of the existing and new buildings that were being used to house the chillers. Additionally, the second most important reason was the delivered accuracy. In the past, most usage had been ignored, but with the rising costs associated with cooling, each individual building must be accountable for individual use. This is just good fiscal responsibility and management from an energy balance standpoint. Turndown was an issue because of seasonal swings in usage based on climate and population in the buildings at any particular time. Therefore, the meters needed to be able to have a large flow span (turndown), which remained accurate during continuous use.
McCrometer's V-Cone
Internal view of V-Cone.

V-Cones have recently been selected for Steam service for mostly the same reasons as they are selected for Chilled Water. Space limitations in new and/or older buildings are a serious concern. V-Cones have the smallest piping requirements of practically any flowmeter and continue to deliver accurate measurement, so they are fiscally responsible and cost effective. Additionally, in steam, they allow condensate and/or other small particulate matter to pass without affecting the measurement, thus giving much better accuracy instantaneously and over time. 

They are very rugged flowmeters which require little or no maintenance, and have a very long expected life even in “tough” service like steam. They can be designed with great turndown (span) and therefore can accommodate changes in flowrates based on demand, seasonal or from other factors.

For more information on V-Cone flowmeters, contact Flow-Tech in Maryland at 410-666-3200, in Virginia at 804-752-3450, or by visiting

Wednesday, February 7, 2018

How To Select a Gas Flow Meter for Your Application

Gas Flow Meter

Here is some very good, basic advice, courtesy of FCI (Fluid Components International) on selecting a gas flow meter.

Match your application to the appropriate measurement technology. Accurate flow measurement starts with selecting the best flow meter technology for your application. Every application has a set of requirements that narrows the choice of technologies. For example, thermal dispersion might work best in a dirty process gas, like biogas, because this technology provides no-moving-parts reliability, direct mass flow measurement, and wide range ability. However, positive displacement might be the best technology choice for the custody transfer of natural gas.

An Instrument Specification Sheet is a good place to find information that will help select the most appropriate flow meter technology for an application. This sheet identifies the application's process temperature and pressure, gas composition, piping configuration, accuracy requirements, and more.

Now forward your application information to vendors that offer the most appropriate flow meter technology. Be sure to include as much information about the application as possible and highlight your realistic performance expectations. Do not request 0.5 percent accuracy if the application needs only 5 percent accuracy. Ask these vendors to evaluate your application and provide a product recommendation. Use the information you receive to revise your specification (if necessary), finalize your preferred vendor list, and prepare your request-for-quote.

FCI flowmeters
Contact Flow-Tech for any flow meter application you may have. Our support engineers are ready to help.

In Maryland - 410-666-3200
In Virginia - 804-752-3450

Monday, January 29, 2018

Understanding Hydrostatic Pressure in Process Control

Hydrostatic pressure transmitter
Transmitter used to measure
hydrostatic pressure. (Yokogawa)
The pressure exerted by a fluid material in a vessel is directly proportional to its height multiplied by its density.

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.

Saturday, January 20, 2018

Tank Overfill Protection

Tank Level Control
Tank Level Control Diagram (Yokogawa)
Protecting against tank overfill allows for process control industry professionals to mitigate potential risk to both their processes and process materials. Different products present different risks regarding tank overfill, but the work of preventing overfill is a universal component of safety, procedural effectiveness, and maximization of resources. If tank overfill does occur, a number of potential negative outcomes could result, especially in the cases of wastewater, chemicals, and petroleum products. Everyone, from management to methodology, needs to be working from the same ideal regarding safety as an inherent priority of process control.

Instead of solely focusing on tank overfill prevention, many corporations have developed written instructions for every individual operator in an organization. Not only do these standards adhere to regulations, but they also meet environmental standards while eliminating accident risk. Six Sigma is an example of data-driven management meant to eliminate potential defects in safety procedures. The idea of pursuing perfection in all components of an organization may originally seem far away from overfill protection. However, previous attempts to confront tank overfill without consideration for the larger organization narrowed operational windows to only consider one part of the system.

Expanding this system to include root causes of overfill prevention instead of solely the mechanisms for prevention has resulted in a more holistic approach to the integration of safety standards. Regulatory requirements for tank metrics, how to operate aboveground versus below ground tanks, and process material specific guidelines are combined with internal company codes. Those two elements are then fused with the Recognized and Generally Accepted Good Engineering Practices which are developed by industry associations. The tri-part approach has resulted in a more collaborative effort to combat tank overfill problems.

One metric employed to prevent tank overfill-related dangers is to measure whether or not the tank in question has the appropriate room to accommodate abnormal process behavior. Considerations such as these mesh with evaluations of pipe size and whether or tanks need to be connected to relief tanks. Assessment of both operational and insurance risk means the entirety of the process must be understood and evaluated so that the interaction between the process materials can be predicted and then mitigated. Whether these components are raw materials, system components, or final products in the latter stages of the process, automated systems combined with operator diligence based on established methodology is the best way to prevent overfill and associated dangers.

To discuss your tank level control and overfill requirements, contact Flow-Tech at or call 410-666-3200 in Maryland, or 804-752-3450 in Virginia.

Saturday, January 13, 2018

How to Adjust Alarms and Pointer for Brooks Instrument Models MT3809G & MT3810G Variable Area Flowmeters

Here are the instructions for the removal and reinstallation of the XP housing indicator cover, and
how to adjust alarms and pointers for Brooks Instrument models MT3809G & MT3810G variable area flowmeters:

Warning: If it becomes necessary to service or remove the instrument from the system, power to the device is disconnected at the power supply.
  1. To begin make sure the float is at rest and there isn’t flow going through the meter.
  2. Using your hands or a strap wrench turn the cover counter clockwise to remove the cover from the housing.
  3. Remove the cover from the housing. The gasket should stay attached to the groove in the housing.
  4. Using a flat blade screwdriver with a 1/8" blade, hold the red alarm pointer and turn the screw counterclockwise to loosen the pointer, slide it to desired position on scale and tighten screw.
  5. Using a flat blade screwdriver with a 1/8" blade, hold the pointer and turn the screw to align with the “R” on the scale. It may take a few adjustments to get the pointer aligned to the “R”.
  6. To replace the cover, place the cover against the housing and turn the cover clockwise. Note, it will take several rotations to tighten the cover and the cover must be in contact with the gasket to keep a watertight seal.

MT3809G & MT3810G variable area flowmeter
Click for larger view.
For additional assistance, contact Flow-Tech in Maryland at 410-666-3200 or Virginia at 804-752-3450 or visit

Thursday, December 28, 2017

Measurement and Calibration Principle of FLEXIM's Non-Invasive Ultrasonic Flowmeter

The principle of FLEXIM's ultrasonic flow measurement of liquids and gases relies on the propagation of ultrasonic wave signals into the medium. This measurement method exploits the fact that the transmission speed of an ultrasonic signal depends on the flow velocity of the carrier medium. Similar to a swimmer swimming against the current, an ultrasonic signal moves slower against the flow direction of the medium than when in flow direction.

For the measurement, two ultrasonic pulses are sent through the medium, one in the flow direction, and a second one against it. The transducers are alternatively working as an emitter and a receiver. The transit-time of the ultrasonic signal propagating in the flow direction is shorter than the transit-time of the signal propagating against the flow direction. A transit-time difference, Δt, can thus be measured and allows the determination of the average flow velocity based on the propagation path of the ultrasonic signals. An additional profile correction is performed by our proprietary algorithms, to obtain an exceptional accuracy on the average flow velocity on the cross-section of the pipe - which is proportional to the volume flow, and when temperature and pressure compensated, to the mass flow.

Since ultrasounds propagate in solids, the transducers can be mounted onto the pipe. The measurement is therefore non-invasive, and thus no cutting or welding of pipes is required for the installation of the transducers.

For more information about FLEXIM, contact Flow-Tech at 410-666-3200 or visit

Wednesday, December 13, 2017

Draeger Tubes & Chip Measurement System Handbook

Draeger is the leader in industrial gas and vapor analysis and have developed more detection devices and tubes for more applications than any other gas detection company.

Draeger sampling tubes allow identification and measurement of different substances even under difficult conditions.

Draeger Chip Measurement System (CMS) combines Chips for measure specific substances with an electronic analyzer for easy-to-use spot-measurement. The analyzer combines an optical system for analyzing the color reaction with a mass flow controller and pump system.

Download the Draeger -Tubes & Chip Measurement System Handbook here.

Thursday, November 30, 2017

Differential Flowmeters: How They Work

Differential Flowmeters
The differential flow meter is the most common device for measuring fluid flow through pipes. Flow rates and pressure differential of fluids, such as gases vapors and liquids, are explored using the orifice plate flow meter in the video below.

The differential flow meter, whether Venturi tube, flow nozzle, or orifice plate style, is an in line instrument that is installed between two pipe flanges.

The orifice plate flow meter is comprised the circular metal disc with a specific hole diameter that reduces the fluid flow in the pipe. Pressure taps are added on each side at the orifice plate to measure the pressure differential.

According to the Laws of Conservation of Energy, the fluid entering the pipe must equal the mass leaving the pipe during the same period of time. The velocity of the fluid leaving the orifice is greater than the velocity of the fluid entering the orifice. Applying Bernoulli's Principle, the increased fluid velocity results in a decrease in pressure.

As the fluid flow rate increases through the pipe, back pressure on the incoming side increases due to the restriction of flow created by the orifice plate.

The pressure of the fluid at the downstream side at the orifice plate is less than the incoming side due to the accelerated flow.

With a known differential pressure and velocity of the fluid, the volume metric flow rate can be determined. The flow rate “Q”, of a fluid through an orifice plate increases in proportion to the square root the pressure difference on each side multiplied by the K factor. For example if the differential pressure increases by 14 PSI with the K factor of one, the flow rate is increased by 3.74.

Monday, November 27, 2017

Small Line Size Flow Measurement without Moving Parts

ST75 Series

Excellent for Gas Sub-Metering, Boiler Fuel-To-Air Mixing, Chemical Injection & Much More

Plant and process engineers who need accurate flow detection or measurement of air, gases, or liquids in smaller pipe sizes will find several diverse flow instrument solutions available from Fluid Components International (FCI).  Using advanced, ultra-reliable thermal dispersion flow measurement technology with no-moving parts, FCI’s ST75 Series and ST100L Air/Gas Flow Meters and FLT93L Flow Switch provide ideal solutions for use in 0.25 to 2 inch (DN6 to DN50) pipe or tubing. They excel where low flows, wide-turndowns, dirty fluids, HazEx or harsh installations are among the applications factors.

These flow instruments offer many advantages for service in a wide range of applications: plant, building or lab gas sub-metering, small inlet air/gas feed lines for boilers, gas relief valve monitoring, chemical injection, compressed air systems, CO-Gen or CHP gas fuel measurement and control, sampling systems, and more.  Many small process line applications are difficult to measure reliably with high repeatability due to variations in temperature and pressure, and have wide flow rates.  FCI’s thermal flow meters and switches are unaffected by, or have on-board compensation for, temperature and pressure changes and, in addition to superior detection of low flow rates, provide 100:1 turndown as a standard feature.  FCI’s highly reliable, small line air/gas flow meters and aid/gas/liquid flow switches combine state-of-art electronics technology with application fluid-matched flow sensors and laboratory calibration in rugged packages designed for the most demanding plant operating environments. 
FLT93L Flow Switch
FLT93L Flow Switch

Thermal flow sensor technology developed by FCI relies on the relationship between flow rate and the cooling effect.  With no moving parts and minimal invasiveness, these meters and switches provide a highly repeatable, accurate, low cost, easy-to-install solution and there’s virtually no maintenance required over a long life.  FCI’s ST75 Series Air/Gas Flow Meters are ideal for lines sizes from 0.25 (6mm) to 2 inches (51mm).  Gas or air measurement accuracy is available up to 1% of reading, ±0.5% full scale. The ST75 Meters feature a wide 100:1 turndown and will measure from 0.01 to 559 SCFM [0,01 to 950 NCMH] depending on pipe size.

The meter’s electronics are housed in a rugged, IP67 rated enclosure with dual conduit ports in either NPT or M20 threading. The instrument comes standard with dual 4-20 mA outputs and a 500 Hz pulse output. The models ST75A and ST75AV include HART as well as NAMUR compliant 4-20 mA outputs and a SIL compliance rating and 2 year warranty.  Global agency approvals for Div.1/Zone 1 HazEx installations include FM, FMc, ATEX, IECEx, EAC and more. 

The best-in-class ST100L Air/Gas Flow Meter is a next generation instrument that combines feature- and function- rich electronics with advanced flow sensors. It is designed in a spool piece configuration in 1-, 1.5- or 2-inch tubing, schedule 40 and schedule 80 piping.  It measures air/gas flows from 0.0062 to 1850 SCFM [0.01 to 3,140 Nm3/h] with superior accuracy to ± 0.75% reading, ± 0.5% full scale; and repeatability of ± 0.5% reading. 

ST100L Air/Gas Flow Meters
ST100L Air/Gas Flow Meters
Whether the plant’s output needs are traditional 4-20 mA analog, frequency/pulse or advanced digital bus communications such as HART, Foundation Fieldbus, PROFIBUS, or Modbus, the ST100L is available with any of them.  Its digital bus communications also are certified and registered devices with HART and Foundation Fieldbus.  Global approvals include:  FM, FMc, ATEX, CE, CSA, IECEx, EAC, NEPSI and Inmetro.  It SIL compliant and is an all-welded design to ensure no leakage when used with volatile gases like hydrogen. 

For applications lacking enough straight-run, both ST75 Series and ST100L can be supplied with Vortab flow conditioning built-in to the spool-piece flow body. Its wide selection of available process connections include male and female threaded and flanges are standard.   The FLT93L Flow Switch is a dual function, dual trip point/alarm point precision switch.  It is field settable for trip point on flow rates and temperature, and as any high or low value of either flow or temperature.  The FLT93L’s setpoint range is: 0.015 to 50 cc/sec [0.0009 to 3 fps] for water-based liquids; 0.033 to 110 cc/sec [0.002 to 6.6 fps] for hydrocarbon-based liquids; and 0.6 to 20,000 cc/sec [0.036 to 1198 fps] for air and gases.

Trip point accuracy is ± 0.5% reading or ± 0.04 fps [± 0.012 mps] (whichever is higher) in liquids and ± 0.5% reading or ± 2 fps [± 0.06 mps] (whichever is higher in air or gases.   The FLT93 has been designed for use and longest service life in the most rugged, harsh operating environments. It is available in both aluminum and stainless steel IP67 rated housings, carries HazEx agency approvals for FM, FMc, ATEX, IECEx, EAC, Inmetro, NEPSI, meets CRN and European PED and is SIL 2 compliant. It is available in numerous wetted materials and process connection options, and has universal DC/AC power supply. 

For more information on Fluid Components, Inc. products in Maryland and Virginia, contact Flow-Tech at 410-666-3200 or visit

Monday, November 20, 2017

Understanding Mass Flow Controller (MFC) Metrology & Calibration

Mass flow controllers (MFCs) precisely deliver fluids, mainly process gases, into bioreactors and other process systems. The stable, reliable and repeatable delivery of these gases is a function of four key factors:
  • The quality and sophistication of the MFC’s design.
  • The application set-up, which covers the acceptable level of  fluid delivery accuracy a given process requires.
  • Metrology: what specific techniques are used to test, measure and con rm MFC accuracy.
  • Calibration checks: how an MFC is calibrated on an ongoing basis.
It’s common to extensively investigate an MFC’s technical characteristics and capabilities, as well as analyze and ensure that the MFC technology chosen fully satis es each operation’s unique process requirements. Equally important is the role that metrology, which includes testing reference standards and calibration practices, plays in the performance and long-term value of biopharmaceutical process equipment MFCs. In the eBook below, we will provide a deeper understanding of metrology’s role in how MFCs are used and managed in these systems. This includes:
  • The key elements of MFC accuracy and why calibration is important
  • How MFC calibration reference standards are used and why selecting the right standard matters
  • The role that “uncertainty” plays in calibrating MFCs
  • Factors that can lead to improper calibration
Please review the eBook embedded in this post below, or if you prefer, you can download your own PDF copy here - Understanding Mass Flow Controller (MFC) Metrology & Calibration. For more information about MFC's, contact Flow-Tech at or call 410-666-3200.

Saturday, November 11, 2017

Clamp-on, Transit-time Difference Ultrasonic Flowmeters Ideal for HVAC Retrofit and New Construction

Transit-time Difference Ultrasonic Flowmeters
Transit-time Difference Ultrasonic Flowmeters (Flexim)
There are many reasons for large commercial buildings, medical centers, museums, airports, sports complexes, federal institutions and military complexes to invest in building energy optimization efforts. Better and more efficient operation of HVAC equipment can reduce the buildings energy and operational costs significantly.

Controlling flow, temperature and pumps can provide energy cost savings of over 20%. Many campus energy managers believe that the biggest user of energy in any complex is the HVAC system, and the key to saving energy in HVAC systems is an accurate and reliable flow metering capability.

Better efficiency of the heating and cooling infrastructure of a building also leads to more environmentally friendly buildings, something that has become a social prerogative of building owners and operators.  Older buildings were not built with BTU meters as metering requirements were added to buildings through increased regulations.

Submetering the buildings heating and cooling systems have become increasingly more important, as building owners are both mandated to meter these utilities and have a financial interest in the accuracy of these BTU measurements. The problem historically is that nearly all flow meters are designed for gradual failure due to direct contact with the fluids they are monitoring and the particulate accumulation on the sensors.

Clamp-on, transit-time difference ultrasonic flowmeters are the ideal retro-fit flowmeter, and also should receive strong consideration for new building construction. Transit-time difference ultrasonic clamp on flowmeters exploit the fact that the transmission speed of an ultrasonic signal depends on the flow velocity of the carrier medium - kind of like a swimmer swimming against the current. The signal moves slower against the flow than with it.

How Transit-time Difference Ultrasonic Flowmeters Work

The flowmeter sends ultrasonic pulses through the process medium - one in the same direction as the
flow and one in the opposite direction. The flowmeter's transducers alternate as emitters and receivers. The transit time of the signal going with the flow is shorter than the one going against. The flowmeter measures transit-time difference and determines the average flow velocity of the process medium. Since ultrasonic signals propagate in solids, the flowmeter can be conveniently mounted directly on the pipe and measure flow non-invasively.

Contact Flow-Tech with your questions about any flow measurement application. Reach them at 410-666-3200, or visit

Tuesday, October 31, 2017

Understanding HART Protocol

A current loop using sensing and
control transmission with HART protocol
overlaid on the 4–20 mA loop.
The Highway Addressable Remote Transducer Protocol, also known as HART, is a communications protocol which ranks high in popularity among industry standards for process measurement and control connectivity. HART combines analog and digital technology to function as an automation protocol.

A primary reason for the primacy of HART in the process control industry is the fact that it functions in tandem with the long standing and ubiquitous process industry standard 4-20 mA current loops.

The 4-20 mA loops are simple in both construction and functionality, and the HART protocol couples with their technology to maintain communication between controllers and industry devices. PID controllers, SCADA systems, and programmable logic controllers all utilize HART in conjunction with 4-20 mA loops.

HART instruments have the capacity to perform in two main modes of operation: point to point, also known as analog/digital mode, and multi-drop mode. The point to point mode joins digital signals with the aforementioned 4-20 mA current loop in order to serve as signal protocols between the controller and a specific measuring instrument. The polling address of the instrument in question is designated with the number ì0î. A signal specified by the user is designated as the 4-20 mA signal, and then other signals are overlaid on the 4-20 mA signal. A common example is an indication of pressure being sent as a 4-20 mA signal to represent a range of pressures; temperature, another common process control variable, can also be sent digitally using the same wires. In point to point, HART’s digital instrumentation functions as a sort of digital current loop interface, allowing for use over moderate distances.

HART in multi-drop mode differs from point to point. In multi-drop mode, the analog loop current is given a fixed designation of 4 mA and multiple instruments can participate in a single signal loop. Each one of the instruments participating in the signal loop need to have their own unique address.

Image courtesy of  Dougsim (Own work) [CC BY-SA 4.0], via Wikimedia Commons

Monday, October 9, 2017

5 Myths of Dust Explosion Propagation

Fike explosion testing
Dust explosion propagation testing at Fike labs.
Abstracted from
"Dust Explosion Propagation: Myths and Realities"
by Fike Corporation

The unfortunate propensity of dust explosions to destroy entire facilities and claim lives has been reported in numerous past incidents.

Powder handling processes are often comprised of interconnected enclosures and equipment. Flame and pressure resulting from a dust explosion can therefore propagate through piping, across galleries, and reach other pieces of equipment or enclosures, leading to extensive damage.

While the ability of dust explosions to propagate has been widely recognized, some misconceptions lead to the false sense of security that explosion isolation is not required.

This post will enumerate, illustrate and unravel 5 common myths about explosion propagation. Download the full Fike White Paper here, or read it in full at the bottom of this post.

Myth #1: A large amount of dust is needed for an explosion to propagate.

Dust explosions do not need large amounts of fuel to propagate.

A 1 mm layer can create a dust explosion hazard in a typical room. The explosion only needed a 1/100 inch layer of dust on the ground to fully propagate.

Myth #2: A dust explosion starting in a vented vessel cannot propagate through connected pipes.

It is a common belief that protecting an enclosure, by means of venting or suppression, will affect explosion propagation in such a manner that no explosion isolation is needed at all. 

Although venting protects a vessel from the high pressures generated by an explosion, it does not necessarily prevent the explosion from being propagated through piping into other vessels.

Myth #3: A dust explosion cannot propagate against process flow. 

An argument also often heard is that a dust explosion cannot propagate against pneumatic process flow. 

An explosion is capable of traveling both with and against process flow, even over long distances.

Myth #4: A dust explosion weakens as it propagates.

Literature includes numerous discussions about explosion behavior in interconnected vessels. 

Experimental evidence has shown that explosions not only propagate, but become increasingly more damaging.

Myth #5: Small diameter pipes do not support dust explosion propagation.

Dust explosion propagation in small pipes has always been a controversial topic. The primary argument being that flame propagation is challenged due to heat loss to the pipe walls.

While conditions for dust explosions to propagate in relatively small diameter pipes are not yet fully established, their ability to propagate has been clearly demonstrated by several researchers.

Contact Flow-Tech with any questions regarding explosion protection testing, isolation valves, vents and systems at or call 410-666-3200.

Saturday, September 30, 2017

Campus Metering: Why Meter?

Instrumentation Energy Management
Schools, universities, medical centers and federal building
use instrumentation for energy management.

Energy and water managers have long known the value of metered data. With recent advances in energy and water metering and information systems resulting in increased functionality at lower costs, obtaining these data in a cost-effective manner is now a standard practice. Whether energy and water resource managers are trying to comply with legislated and mandated metering requirements, or looking to apply accepted building management best practices, such as utility bill verification or benchmarking, today’s metering technologies can provide the information needed to meet energy and water goals, save money, and improve building operations.

Metering of energy and water utilities has seen an increase in interest, application, and technology
Clamp-on flow meter
Clamp-on flow meter (Flexim)
advancement in both the private and the public sectors. One significant driver of this heightened interest is the ongoing modernization of the nation’s electric infrastructure with the move toward the smart grid and smart meters. Another significant driver, specific to the Federal sector, includes the legislative mandates for metering of Federal buildings.

The Business Case for Metering

The application of meters to individual buildings and energy-intensive equipment provides facility managers and operators with real-time information on how much energy has been or is being used. This type of information can be used to assist in optimizing building and equipment operations, in utility procurements, and in building energy budget planning and tracking.

It is important to keep in mind that meters are not an energy efficiency/energy conservation technology per se; instead, meters and their supporting systems are resources that provide building owners and operators with data that can be used to: 
Flow computer
Flow computer (KEP)
  • Reduce energy and water use
  • Reduce energy and water costs
  • Improve overall building operations 
  • Improve equipment operations
How the metered data are used is critical to a successful metering program.

Depending on the type of data collected, these data can enable the following practices and functions:
  • Verification of utility bills
  • Comparison of utility rates
  • Proper allocation of costs or billing of reimbursable tenants 
  • Demand response or load shedding when purchasing electricity under time-based rates 
  • Measurement and verification of energy project performance 
  • Benchmarking building energy use 
  • Identifying operational efficiency improvement opportunities and retrofit project opportunities 
  • Usage reporting and tracking in support of establishing and monitoring utility budgets and costs, and in developing annual energy reports. 
Most of the metered data uses listed above will result in a reduction in energy and water costs. The degree of cost reduction realized will depend on the unit cost of the energy and water being saved and on the effectiveness with which the site analyzes the data and acts upon its findings and recommendations. Examples of additional metering benefits can include:
Inline flowmeter
Thermal dispersion flow meter (FCI)
  • Supporting efforts to attain ENERGY STAR and/or green building certifications 
  • Promoting tenant satisfaction by providing information that tenants find useful in managing their operations 
  • Prolonging equipment life (and reducing capital investment requirements) and improving its reliability by verifying the efficient operation of equipment 
  • Assessing the impact of utility price fluctuations prior to or as they happen, allowing sites/agencies to address budget shortfalls on a proactive basis. 
Metering options will change in response to new material, electronic, and sensor development, as well as new and additional requirements for real-time data information. Future expansion of a metering system should be considered, as well as introduction of new metering and sensor technologies, based on the best available information, but be careful not to over design a system, thus unnecessarily increasing its cost.

Contact Flow-Tech with questions about improving your facilities energy management systems.  

Monday, September 11, 2017

Industrial Level Measurement

Point level
Point level switch (FCI)
In many industrial processes, the measurement of level is critical. Depending on the nature of the material being measured, this can be a simple or complex task. Several different technologies for sensing level are briefly explained here.

Direct Method

The direct method of level measurement calculates levels instantly using physical properties, like buoyancy and fluid motion. Beginning from the simplest, the following are the three main types:
  • Sight glass type
  • Float type
  • Magnetic level gauge
Sight glass measures liquid in tanks. A scaled glass tube with metallic covering it is attached to the top and bottom edges of the tank and, as the liquid moves up and down, the level in the tube fluctuates in the same way.

Float type measurement makes use of buoyancy: a float device follows the liquid level while sitting atop it. As the liquid moves so does the float device; a cable, attached to the top of the device, is rigged to a calibrated scale with a pointer in the middle. The up and down movements pull the string which pulls the pointer, thus showing where the liquid level is.

 A magnetic level gauge looks like a thick thermometer and is attached to the end of a vertical chamber. This vertical chamber contains a magnetic float, a permanent magnet, which floats on the top of the liquid level in the tank.

There is one more thing also attached to the outside of the tank: an indicating scale with small metallic strips. These strips are white and red sided flippers, rotating 180° whenever the float magnet attracts them while passing over. Whenever the float magnet is above, the strips will flip red side up, indicating the tank’s level.

Indirect Method

In the indirect method of level measurement, the level of a liquid is calculated by a variable that changes according to the level. There are four main types:

  • Pressure gauge type
  • Differential pressure type
  • Ultrasonic type
  • Radar type
The pressure gauge is a simple method; a pressure gauge is attached near the bottom of tank and pressure, exerted by the tank, is calculated. The gauge changes in time with the tank’s liquid pressure, and the measurement is made according to the height of the liquid.

Radiometric Level
Radiometric Level (RONAN)
The differential pressure method (DP method) is another widely used method in industry. This method requires a DP transmitter and a port; these two parts are connected to the external tank at opposite ends. The differential pressure in the tank is measured between the DP transmitter at the bottom and the port at the top; the output of the differential pressure calculated by the DP transmitter is proportional to the liquid level. The more liquid in the tank, the more pressure is at the transmitter; the less liquid in the tank, the more pressure at the port.

The ultrasonic method is a no-contact type. A transmitter is mounted atop the tank and ultrasonic sound waves are sent from the transmitter toward the surface of the measured fluid. An echo of the wave is calculated and the time it took for the wave to reach its end goal from the transmitter becomes its distance. The time of the length of the distance is then calibrated in terms of the level of process material.

The radar method is a no-contact type and it uses electromagnetic waves. Electromagnetic waves are sent through a transmitter to the surface of the measured material. There is a receiver toward the bottom of the tank which takes a portion of the energy sent from the wave and then reflects it back toward the surface of the medium. The reflected energy then becomes calibrated into level measurement.

Industrial level control requires deep knowledge and understanding of many process variables, such as media compatibility, interfaces, head pressures, material densities, and mechanical considerations. It's always recommended that an experienced consultant be involved with the selection and implementation of any industrial level device.

Wednesday, September 6, 2017

Fluid Components Series FS10 Quick Setup Mode Demonstration

FS10 Series Flow Switch and Monitor
FS10 Series Flow Switch and Monitor
The FS10 Series Flow Switch and Monitor is manufactured by Fluid Components, Inc.

The FS10A is a universal flow switch and monitor specifically designed for gas and liquid process analyzer sampling systems. The FS10A is a fast responding, highly repeatable sensor which installs easily into a standard tube tee fitting or new SP76 (NeSSI) modular manifold.

The FS10i is a universal flow switch and flow monitor designed for simple insertion into ½” (13mm) or larger diameter pipes and square ducts. The unit is suitable for either liquid or air/gas applications. It is fast responding and highly repeatable to both increasing and decreasing flow rate changes.

The video below explains the procedure for accessing and setting the quick setup modes.

For more information on any Fluid Components, Inc. (FCI) flow meter in Maryland and Virginia, call 410-666-3200 or visit

Thursday, August 31, 2017

Process Instrument Calibration

Meriam MFC5150 HART Communicator
Meriam MFC5150
HART Communicator
Calibration is an essential part of keeping process measurement instrumentation delivering reliable and actionable information. All instruments utilized in process control are dependent on variables which translate from input to output. Calibration ensures the instrument is properly detecting and processing the input so that the output accurately represents a process condition. Typically, calibration involves the technician simulating an environmental condition and applying it to the measurement instrument. An input with a known quantity is introduced to the instrument, at which point the technician observes how the instrument responds, comparing instrument output to the known input signal.

Even if instruments are designed to withstand harsh physical conditions and last for long periods of time, routine calibration as defined by manufacturer, industry, and operator standards is necessary to periodically validate measurement performance. Information provided by measurement instruments is used for process control and decision making, so a difference between an instrument's output signal and the actual process condition can impact process output or facility overall performance and safety.

In all cases, the operation of a measurement instrument should be referenced, or traceable, to a
universally recognized and verified measurement standard. Maintaining the reference path between a field instrument and a recognized physical standard requires careful attention to detail and uncompromising adherence to procedure.

Calibration gauges
Calibration gauges (Permacal)
Instrument ranging is where a certain range of simulated input conditions are applied to an instrument and verifying that the relationship between input and output stays within a specified tolerance across the entire range of input values. Calibration and ranging differ in that calibration focuses more on whether or not the instrument is sensing the input variable accurately, whereas ranging focuses more on the instrument's input and output. The difference is important to note because re-ranging and re-calibration are distinct procedures.

In order to calibrate an instrument correctly, a reference point is necessary. In some cases, the reference point can be produced by a portable instrument, allowing in-place calibration of a transmitter or sensor. In other cases, precisely manufactured or engineered standards exist that can be used for bench calibration. Documentation of each operation, verifying that proper procedure was followed and calibration values recorded, should be maintained on file for inspection.

As measurement instruments age, they are more susceptible to declination in stability. Any time maintenance is performed, calibration should be a required step since the calibration parameters are sourced from pre-set calibration data which allows for all the instruments in a system to function as a process control unit.

Typical calibration timetables vary depending on specifics related to equipment and use. Generally, calibration is performed at predetermined time intervals, with notable changes in instrument performance also being a reliable indicator for when an instrument may need a tune-up. A typical type of recalibration regarding the use of analog and smart instruments is the zero and span adjustment, where the zero and span values define the instrument's specific range. Accuracy at specific input value points may also be included, if deemed significant.

The management of calibration and maintenance operations for process measurement instrumentation is a significant factor in facility and process operation. It can be performed with properly trained and equipped in-house personnel, or with the engagement of subcontractors. Calibration operations can be a significant cost center, with benefits accruing from increases in efficiency gained through the use of better calibration instrumentation that reduces task time.

Contact Flow-Tech at 410-666-3200 in Maryland and 804-752-3450 in Virginia for any calibration question or requirement.

Monday, August 28, 2017

Installation and Operation of the Brooks Instrument GF40

Brooks Instrument GF40
Brooks Instrument GF40
The Brooks® GF40 (elastomer seal) thermal mass flow controller (MFC) and thermal mass flow meter (MFM) achieves unprecedented performance, reliability, and flexibility in many gas flow measurement and control applications.

At the heart of the GF40 is Brooks’ patented 4th generation MultiFloTM capable device. MultiFlo overcomes a long-standing limitation of many thermal MFCs – when changing gas types, a simple correction factor, such as the ratio of heat capacities between the calibration gas and new gas, cannot account for accuracy-robbing viscosity and density differences. The Brooks MultiFlo database is built on thousands of native gas runs to establish correction functions that account for both thermal and physical differences among gases making the GF40 Series among the most accurate and flexible MFCs/MFMs available today. The Brooks GF40 Series is the perfect choice for customers who use thermal mass flow controllers or thermal mass flow meters on a variety of gases, who need to change gas type frequently, or who need to re-range while preserving gas measurement and control accuracy.

We have provided a Brooks GF40 installation and operation manual below for your convenience. To download your own Brooks GF40 IOM (PDF), click this link.