Tuesday, March 29, 2016

A Specialty Temperature Sensor Specifically for Improving Heat Tracing Applications

Heat Tracing RTD
Heat Tracing RTD (courtesy of
Applied Sensor Technologies)
A temperature sensor is key to any heat tracing application as it provides temperature feedback about the pipe temperature, which in turn, is used turn on or off the heating system (electric pipe tracing or steam control valve).

The temperature sensor is critical for both categories of heat tracing - process temperature maintenance and freeze protection.  Failure to maintain process temperature in a pipe or vessel could significantly effect product quality, or cause failure of ancillary equipment such as pumps, valves, and compressors. Properly protecting against freezing keeps pipes from bursting or product from blocking the flow. For both situations, product maintenance and freeze protection, accurate and reliable temperature sensing is critical.

There’s a new and very innovative line of RTD temperature assemblies specifically designed for heat tracing applications. The unique, replaceable element concept can save customers both time and money, plus increase overall system reliability and up-time.

A major refining company determined that they save over $1,000 in labor each time they have to replace a sensor and have reduced their repair time from two days to less than one hour.

The design consists of a terminal head and right-angle shaped outer sheath, with a curved weld-pad at the end. The replaceable RTD element assembly is contained in the outer tube and, when installed, presses against the pipe. Heat transfer is excellent and heat conduction away from the element is minimal. Should the element ever need to be replaced, it's a five-minute job to open the terminal head, unwire the sensor, slide it out and slide a new one in.

For more information, contact:

Ives Equipment
(877) 768-1600

Monday, March 21, 2016

The Ten Things Everyone Should Know about pH and ORP

pH ORP probe
pH ORP probe
(courtesy of AquaMetrix)
Reprinted with permission from AquaMetrix

1. pH measurements are only good to 0.1 pH units

Electrodes are funny things. They are the only electronic components that don’t even have specifications listed in their data sheets. One major figure of merit, the impedance of the glass electrode, is on the order of megahoms and can vary by a factor of two. Cross sensitivity to other ions (e.g. sodium), response time and differences between any two electrodes limit the accuracy of measurement. Expecting accuracy of greater than 0.1 pH units is unrealistic.

2. Speaking of accuracy... It is not the same as precision.

For a consistent process a pH probe can achieve precision of results to within 0.02 units but it’s accuracy will always be limited by variables such as calibration accuracy, high sodium content or Careful routine calibration, however, will narrow the gap between the accuracy of readings closer to the lower level of precision.

3. ORP measurements are only good to ± 20 mV. 

Once again the measurement of ORP might be characterized by a high precision but the accuracy of the reading is constrained by the difficulty of calibration, as explained in point 6, and the non-buffered calibration solutions that allow the ORP value of the calibration solutions to change over time. Whereas the buffered composition of pH calibration solutions insures that they will change minimally an ORP calibrations solution is a mixture of Fe2+ and Fe3+ salts. Just the addition of air to the mixture will increase the ORP of the mixture. So don’t look for “NIST traceable” on the label of an ORP calibration solution.

4. ORP measurements are relative.


The process electrode is nothing more than a platinum (or gold) band upon which oxidation (reduction) reactions take place. To complete the circuit, as in all potentiometric devices, is a reference electrode. Usually that is the same Ag/AgCl electrode used in a pH probe so the REDOX potential that you read is the difference between the Pt band process electrode and the arbitrarily chosen reference electrode. What matters most with an ORP measurement is its change to an agreed upon standard.

5. pH calibration requires two points.


Calibration measures the response of an instrument as one changes the measurement variable in a known way. For pH measurements that measurement variable is the concentration of hydrogen ions. One calibrates a pH probe by drawing a line through points representing the response of a pH probe to more than one H+ ion concentrations (or pH values). Therefore calibration requires at least two points.

6. ORP calibration can only realistically be done with one point.

This sounds like a reversal of point 4 but it’s not. ORP is not a measure of any one species (e.g. H+ ions or oxygen molecules). It measures the collective REDOX potential of everything in the water. Furthermore calibration solutions, e.g. 200 mV Light’s solution and 600 mV Zobell’s solution are two completely different mixtures of reagents. Therefore all we can is choose one calibration solution and calibrate for it.

7. ORP measurements can be slow.

Stick an ORP probe in a calibration solution and you will get a steady reading with- in half a minute. Take the same probe and stick it in a glass of tap water and it might take 20 minutes for the read-

ing to settle to the 200-300 mV that is typical of tap water. The response of the process electrodes to the REDOX reactions that take place on the surface of a Pt electrode depends on the speed of the many reactions that give the potential and the rate at which molecules diffuse through the water. The Fe2+ and Fe 3+ ions that comprise most of the ORP value in calibration solutions react very quickly with the Pt but the Cl- and dissolved oxygen that make up tap water react much more slowly. So the key to successful ORP measurement is patience.

8. pH measurements must be temperature compensated to be accurate.


A pH measurement is the determination of H+ ions in solution. Higher temperature causes the chemical activity to increase and the pH reading to increase accordingly. So we must remove the temperature effect by measuring it and using the well known Nernst equation to correct it for the reading at 250C. (The correction is quite simple. The pH value is proportional to temperature when the latter is an absolute value (i.e. in Kelvins).

9. ORP measurements are affected by temperature but are NOT corrected for it.

An ORP value simply reflects the ability of whatever is in the water to oxidize whatever contaminants are in the water. Of course oxidation speeds up at higher temperatures. But since ORP measures the rate of chemical reactions and not any one chemical species there is no need to correct it. However we can convert the temperature reading to the ORP that we would measure at 250 C so that we have a basis for comparing the chemistry of the process. That’s why we provide a temperature sensing thermistor or RTD with our differential ORP probes.

10. A differential probe properly cared for will last a long time but it won’t last forever.

Over time chemicals in the process make their way through the junction or salt bridge and into the pH 7 buffer that bathes the reference electrode. Manufacturers go to great length to minimize this contamination but they can only slow it down. Aquametrix differential probes allow the user to cheaply and quickly replenish both the pH 7 solution and the salt bridge so that our probes our industry leaders when it comes to probe lifetime. Nonetheless electrodes themselves lose their efficiency as the glass becomes contaminated and/or eroded by the process. However the good news that, with routine calibration and maintenance a differential probe can last for years in most environments.

Thursday, March 10, 2016

Automation Federation, Oil & Gas and DHS Work Together for Cybersecurity

The Oil & Gas industry explore, extract, and deliver vital energy via a finely-tuned network of worldwide control systems. These systems used to be isolated proprietary systems, but they're now connected to the Internet just like so many other of our critical infrastructures, and are now susceptible to the same vulnerabilities that we see reported on a daily basis.

Since 2006 the Automation Federation has been the Host Organization for LOGIIC (Linking Oil and Gas Industry to Improve Cybersecurity.) This has been a successful collaboration between the Automation Federation, the Department of Homeland Security, and the members of LOGIIC.

Over the past decade, the LOGIIC consortium has designed tools and techniques to protect critical systems on a global scale, from research & development through practical implementation. LOGIIC is a visionary project. It was one of the first of its kind including partners that would normally compete against each other. LOGIC is about collaborating in cyber security.


The Cyber Security Division of the DHS Science & Technology Directorate leads an ongoing consortium that began with a single partner in 2004 and now includes five major oil & gas companies and the Automation Federation, supported by world-class vendors and research organizations. It's a global engagement with global impact on cyber security. LOGIIC is one team. It's important to be international because a threat does not come from one country or from another one country.

Since its inception, LOGIIC has successfully completed eight major projects, with plans for many more.  Upon completion of selected projects, LOGIIC delivers public reports to help elevate best practices across the entire industry. Both the member companies and the government are putting funds towards these projects which benefits not only the private sector, but also the public interest. Companies are applying these learnings within their organizations, because it helps bridge the gap between information technology and the industrial-environment sides of the organization.

The lessons learned through the LOGIIC projects allows the roll out of higher level cyber security and protection across all the industries. DHS is a key contributor to LOGIIC and to the success of the projects year after year. In addition to providing that technical expertise and environments such as labs and research institutes, they’re able to conduct substantial testing, and act as a conduit to make it all happen. LOGIIC started as a new model and a vision. Members came to the table, bought into the vision, and now LOGIIC is delivering real results to protect the modern industrial infrastructure.

To recognize the success of LOGIIC, DHS has released a video that features the efforts of LOGIIC. You can see the video here on the Ives Equipment Community Page.

Sunday, February 28, 2016

Compact Coriolis Flowmeter with NTEP Custody Transfer Approval

NTEP approval
NTEP approval for
custody transfer

When oil and gas are physically transferred from one operator to another, the term custody transfer is used to describe the transaction. It is understood as the transfer of fluid material defined by a metering device, at a given location, to another party. Custody transfer occurs at a variety of locations including from production platforms to ships, trucks, railcars, barges, and also at the final destination, such as the processing plant or refinery.

Accuracy is very important in custody transfer as both parties and instruments such as flowmeters must have approval by the organizations such as the American Petroleum Institute (API) or the National Conference on Weights and Measures (NCWM).

The National Type Evaluation Program (NTEP) is an evaluation program overseen by the National Conference on Weights and Measures (NCWM). Manufacturers who carry NTEP approval comply with local state and government regulations regarding transactions selling, purchasing, exchanging, custody transfer, or establishing the cost for services on based on weight.

NTEP approval
Compact Coriolis flowmeter
with NTEP approval
Siemens has announced the SITRANS FC430 Coriolis flow meter now has National Type Evaluation Program (NTEP) CT approval for the USA and Canada. The approval is for both the measurement of volume and mass liquid flow, and offers high accuracy measurement with minimum of pressure loss. The SITRANS FC430's performance and custody transfer approval makes it an excellent fiscal metering tool for diverse industries such as oil and gas, petrochemical, and food and beverage.

For more information, contact:
Ives Equipment
www.ivesequipment.com
877-768-1600

Sunday, February 21, 2016

Understanding Condensate Pumps on a Steam Distribution System

industrial steam system
Diagram of industrial steam system
(courtesy of Watson McDaniel)
A condensate pump is a type of pump used to pump the condensate (water) produced in an industrial steam system. The primary application for the condensate pump is pumping condensate from a process application or condensate collection area back to the condensate return system.

In certain cases, the steam pressure of the system may be sufficient to push the condensate through the steam traps and condensate return lines, back to the condensate holding tank in the boiler room. In most practical situations, however, one or more condensate return pumps are required to assist in overcoming gravity, pressure drops from long piping runs, and back pressures in return lines.

Condensate Return Pumps are either electrically-driven centrifugal pumps or non-electric mechanical pumps that use steam pressure as the motive force to pump the condensate. Non-electric pumps are referred to as Pressure Motive Pumps (PMPs).

A facility will often have a separate area that contains various components required for the generation of steam, such as a boiler, condensate holding or deaerator (DA) tank, boiler feed pump, water treatment, etc. Regulated by the boiler control system, the boiler feed pump sends condensate from the holding tank back to the boiler.

Pressure Motive Pumps (PMPs) are non-electric pumps which return condensate back to the boiler room; using steam pressure as the motive force. PMPs can be supplied as stand-alone units – which include a pump tank, the internal operating mechanism, and a set of inlet and outlet check valves, or: as a packaged system – which also includes the vented receiver tank (to collect the condensate) mounted on a common base.

The following is a comprehensive document, courtesy of Watson McDaniel, that provides a good general understanding of steam and condensate systems, traps and condensate pumps. 


For more information, contact:

Ives Equipment
www.ivesequipment.com
(877) 768-1600

Wednesday, February 10, 2016

Coriolis Flow Sensor with 15 RA/230 Grit for Sanitary Applications

Sanitary Coriolis flow sensor
Sanitary Coriolis flow sensor
with 15 RA / 230 Grit finish
on wetted parts.
(Courtesy of Siemens)
In sanitary applications, the finish and the material must be designed for easy and reliable cleaning and sanitation. For decades agencies have required sanitary finishes to comply to minimum standards. But now, many food, Biotech, and Pharma companies are going beyond the minimum regulations and providing high-end finishes because of the reduced sanitation time and reduced bacteria growth these finishes facilitate.

Sanitary applications mandate that stainless steel equipment have a sanitary finish. In very general terms, “sanitary finish” means a smooth, scratch-free, non-corrosive finish. But it’s much more than that. To qualify the finish more accurately, there are two primary terms used:

Roughness Average, or RA: A standard for an average of the peaks and valleys of the metal’s surface, measured in microinches or micrometers. The lower the RA, the smoother the finish.

Grit: The size of the abrasive used in the metal polishing process. Higher grit numbers are associated with higher polishing.

For process control equipment manufacturers, achieving higher-end finishes is not an easy proposition. Providing better finishes requires experience and controlled processes for quality fabrication, as well as possible tooling and production floor changes. Working inside sanitary requirements requires careful handling to prevent contamination from the manufacturing environment. Not all process instrument manufacturers are capable of providing the required environment.

A Coriolis Flowmeter with 15 RA/230 Grit for Biotech and Pharma

Siemens is currently offering a 15 RA/230 Grit surface finish for the FCS400 Coriolis flow sensor internal wetted-tube parts as a special, and will soon be offering it as a standard.

A Coriolis sensor, with such a high end finish, is very attractive to many "clean" industries including chromatography, blood plasma fractioning, chemical synthesis phases, Active Pharmaceutical Ingredient (API) extraction/fermentation and purification, formulation, and  purified API.

Biotech and Pharma manufacturers, in particular, are poised to take advantage of the enhanced 15 RA/230 Grit finish coupled with the inherent benefits of the FCS400 Coriolis flow sensor, namely:
  1. Accurate measurement across the entire range
  2. Zero internal fabrication joints and self-draining design
  3. All metal surfaces eliminate risks from particulates from the breakdown of synthetic materials
  4. No internal fluids to leak into the process
  5. A direct mass flow rate/ and total
For more information, contact:

Ives Equipment
www.ivesequipment.com
(877) 768-1600

Wednesday, February 3, 2016

Next Generation Tail Gas Analyzer

On-Line Process Analytics is a young industry. Now going into the 3rd generation, the paper below covers topics related to the specification, use and long term ownership of SRU process gas analyzers.







AMETEK Process Instruments has been the leader in tail gas analysis for over 40 years-with more than 1,100 installed model 880 NSL analyzers and more than 100 million hours of run time. The Model 888, the successor of the 880 NSL uses field-proven and highly reliable UV technology to accurately monitor the H2S and SO2 concentrations in sulfur recovery tail gas. This compact, rugged analyzer mounts directly on the process pipe, eliminating the complexity and safety issues of fiber optic coupled photometers.

The Model 888 is the evolution of a well proven formula. All the best elements of the iconic 880 NSL are still there; Four year lamp life, no shelter required and steam blow back for ammonia salts.