Archive | 2007

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December 1, 2007
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Viewpoint: Achieving Excellence

1207_richard_l._dunn

Richard L. Dunn, Executive Director, Foundation for Industrial Maintenance Excellence

Two U.S. plants have been selected to receive the 2007 North American Maintenance Excellence (NAME) Award presented by the Foundation for Industrial Maintenance Excellence. The Alcoa Mt. Holly plant, Goose Creek, SC, and the Baldor Dodge Reliance – Dodge Marion plant, Marion, NC, were selected as award winners after evaluation of their applications and onsite audits of their operations by the NAME Award Board of Directors.

Now in its seventeenth year, the NAME Award is widely regarded as the most prestigious recognition in the maintenance function. Awards are presented to individual plants on the basis of their maintenance departments’ ability to provide “capacity assurance for operational excellence” in the areas of organization, work processes and materials management.

In many ways, the two winners represent the breadth of the possible paths to maintenance excellence. One is a large plant, the other small; one a large maintenance organization, the other not. One plant is primarily a round-the-clock continuous process operation, the other a manufacturer of discrete products. One has a long tradition of striving for and exemplifying maintenance excellence, the other has come to this level only recently.

Alcoa Mt. Holly is a 1.5 million-square-foot aluminum smelter that produces about 500 million pounds of aluminum ingots annually. Its 160 maintenance employees support the 24/7 operation of the plant through a wide variety of preventive and predictive maintenance activities, major equipment overhauls and operation and maintenance of the plant’s substation. In recommending the plant for the NAME Award, evaluators noted its long history of outstanding work planning and scheduling, as well as its excellent communications and cooperation with all production areas.

Dodge Marion manufactures mounted tapered/spherical roller bearings in its 174,000- square-foot facility. Its nine-person maintenance department has developed a strong preventive and predictive maintenance program using various total productive maintenance (TPM) processes.

Both plants have demonstrated enviable records for reliability. Furthermore, both demonstrate that a foundation of sound preventive maintenance practices coupled with a plant-wide respect for the value of maintenance is essential to overall excellence.

Established in 1990 as a way to encourage best maintenance practices and a way to honor those who achieve them, the NAME Award program has presented 20 awards over the years with several awards in some years and none in others. In 2000, the volunteers who administer the award program incorporated as the not-for-profit Foundation for Industrial Maintenance Excellence (FIME) to ensure the program’s continuance and independence from commercial influence. The Board of Directors is made up of past award winners and others with a demonstrated devotion to the values the award represents.

To be eligible, a plant must submit a comprehensive application by June 30 in the year of entry. This application is reviewed by the Board of Directors to determine eligibility for an onsite audit. Following this audit, the Board of Directors again meets to decide if the applicant qualifies in all respects for the award.

The NAME Award recognizes that the Alcoa Mt. Holly and Dodge Marion plants have demonstrated their maintenance competence at a world-class level. The Foundation for Industrial Maintenance Excellence is proud to honor their achievements.

Rick Dunn participated in the establishment of the North American Maintenance Excellence Award and has been active in its activities since inception. He was appointed Executive Director when the NAME Award program was incorporated as the Foundation for Industrial Maintenance Excellence. Information on the NAME Award program is available online at www.nameaward.com

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November 1, 2007
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Utilities Manager: Cutting Costs In Process Cooling

New to North America, this proven technology soon may change the way you approach process cooling in your operations.

Although some technologies are constantly changing, at least one has remained virtually unchanged for decades: cooling tower systems. New technology in this arena, however, has at last hit the United States—and it’s changing everything about the way many people approach process cooling. As a utility manager, you might find you want to change your approach, too.

1107_um_cooling_fig1Ecodry is a closed-loop, dry-cooling system that nearly eliminates wastewater problems and drastically lowers energy bills. It does so by completely eliminating traditional cooling towers and the typical hassles associated with them.

The current situation
For over 80 years, cooling towers have been at the center of industrial cooling despite the ongoing expense of water treatment, regular heat-exchanger cleaning, difficult cold-weather operation and substantial water and energy consumption. Traditional cooling towers rely on constant evaporation of water passing through the air, resulting in an ever-increasing concentration of contaminants and dissolved solids. Until recently, cooling tower maintenance professionals have accepted these problems as inevitable. This new system, from the Italian company Frigel, offers an alternative.

While new to North America, the Ecodry system has been proven in well over 5000 installations worldwide. The concept originated in Europe, where energy is more expensive and water quality has been a huge challenge, making the perfection of this technology imperative.

In place of a traditional cooling tower, the Ecodry features a closed-circuit fluid cooler. The water returning from the process is pumped into heat exchangers and cooled with ambient air flow. This process provides clean water at the right temperature to process machines year-round.

The closed-loop design keeps heat exchangers scale-free, minimizing the need for costly chemical consumption and disposal. The ultimate result is a modular, flexible, preengineered system that produces the lowest operating cost and highest reliability for installation anywhere.

1107_um_cooling_fig2Water savings
The endless water challenges related to cooling tower systems include high levels of consumption, chemical treating needs and disposal issues.

Over-consumption occurs as water either evaporates or is dumped down a drain. Both events are inevitable with traditional tower systems, whereas the new closedloop system described here never exposes water to the elements—making it possible to use the same clean water over and over again. The reduced water consumption, when compared to conventional cooling towers, is up to 95%.

Most facilities’ incoming process water is not what you would call ideal. That’s why, in an open cooling tower system, continuous water treatment becomes an expensive part of everyday operations. It’s common for a local chemical representative to visit a plant every couple of months to test and adjust the water. In closed-loop, dry cooling, adjustments are made up front if needed. The time and resources spent on regular testing and treating are completely eliminated.

Many facilities also are struggling with local government regulations on contaminated water disposal. These facilities face large dumping fees, fines or the need to call a service to haul away chemically treated wastewater.

This type of closed-loop system minimizes environmental impact by using the same clean water continuously and not disposing chemically treated water into the ground, lakes and streams. With evaporation virtually eliminated, the Ecodry’s technology poses the lowest risk of refrigerant gas emission into the atmosphere.

Energy savings
According to Frigel, the Ecodry system can reduce energy consumption significantly by eliminating big pump tanks and using efficient fans that only run when needed.

1107_um_cooling_fig3

One of the key energy-saving components is the advanced microprocessor featuring an easy-to-use, remote interface. It not only controls functions of the system but makes the adjustments needed for the system to run at optimum efficiency. Based on ambient temperature and process water temperature, the controller adjusts fan speed and initiates evaporative functions to generate the required cooling capacity in the most efficient way possible. The microprocessor also manages the pumping stations to save energy and boost equipment longevity by controlling water pressure and pump rotation.

To power the fans, the system uses highly efficient, brushless, variable-speed DC servo motors with individual automatic speed control. These maintenance-free motors are 30% more efficient than traditional motors, feature quiet operation (less than 57 dBa), allow any fan to be changed while the equipment is running and offer increased reliability and durability. Overall, the average annual energy consumption of this closed loop system is 0.05 kWh/ton.

How the system works
Besides continuous maintenance, chemical expenses and wasted water, cooling towers also fall short of optimum performance when ambient temperatures soar above 85 F or drop below freezing.

When ambient air reaches 85 F or above, the Ecodry system automatically switches into “adiabatic” mode. Air passes through an adiabatic chamber before reaching the heat exchanger. A fine mist of tap water is “pulsed” into the incoming air stream inside the chamber and humidified air drops the water temperature to, at or below 95 F—even with ambient temperatures as high as 120 F.

The pulsed water evaporates instantly, cooling the air before it impinges on the cooling coils that carry the process water. The coil fins remain dry, thus the term “dry cooling.” To ensure consistent cooling, an advanced control panel continuously adjusts the amount of water sprayed.

Units can deliver heat loads of 17 tons or can be daisychained to deliver capacity up to 3500 tons.

Avoiding freezing
What happens if ambient air dips below 32 F when the plant is not running or a power outage occurs? The Ecodry system’s copper pipes are automatically drained by gravity to protect the unit and avoid icing. Furthermore, it is done without the need for valves, antifreeze or any manual interaction with the system at all. The self-draining process provides completely safe operation in extreme weather conditions.

This function also allows the system to be used for applications where contact with glycol is not tolerated. For facilities in cold-weather climates, partial glycol supplement is an option if the user requests it. It’s not preferred, however, because pure water has the best heat-transfer properties.

1107_um_cooling_fig4For colder weather, Frigel’s technology includes builtin freeze protection that monitors ambient and return water temperatures. In a pure-water system, if the leaving water temperature drops below the setpoint, the controller halts the pumps circulating to the outdoor heat exchanger (made entirely of non-corrosive copper, aluminum, bronze and stainless steel) and the Ecodry automatically drains its water back to an indoor reservoir. The central system then circulates cool water from its indoor tank until it becomes sufficiently warmed to permit sending it outdoors again to the heat exchanger.

Central chiller replacement
The closed-loop system also can be used in conjunction with chiller/temperature control units (Microgels) for individual control of chilled or heated water at each process machine. A single set of uninsulated pipes supplies the process water without heat loss to the chiller/ temperature control unit at each machine. These units offer high flow, precise temperature control and a builtin valve that provides automatic “free cooling” when ambient temperatures are lower than process setpoint.

“This setup is really great. In the winter we get free cooling because we’re sending water outside to cool down to temperature,” said Steve Streff, president of SK Plastics, whose company uses Frigel’s technology (see sidebar below). “Sometimes, the compressors don’t even run because the water’s already cool enough. So, we’re saving money and energy on several fronts.”

Free cooling means using the closed-loop fluid cooler or other non-refrigeration cooling methods in place of the chiller/refrigeration method. The Ecodry can provide free cooling to a variety of processes/devices based on process setpoint and local ambient conditions. This can save up to 80% on energy costs and improve processes the water is serving because of the precise water temperature delivered at individual process machines. This can have quite a positive impact on productivity. UM

 

An SK Plastics Case Study

1107_um_cooling_pic1SK Plastics Molding Inc. in Monroe, WI, once had a conventional cooling tower system, as so many in the industry do. The company always was having trouble with contaminants in the water, dumping that chemically treated water into the environment and then needing to add more chemicals all over again. When it came time to look for a new system as part of plant expansion, company leaders were determined to consider alternatives.

“We’re in a rural area. The water’s terrible,” says Steve Streff, SK’s president. “There’s dust in it, lime, lily pads and dandelions. The water treatment people have to come in and bleed-off all the chemicals added to it. Our heat exchangers were getting plugged and our molds were starting to lime up.”

Streff met with representatives from Frigel North America to discuss their closed-loop, dry-cooling system. What he learned soon started to make sense for his operation. While he was at first skeptical about a system so different from the one to which he was accustomed, the fact that the Ecodry didn’t require constantly adding water and chemicals had significant appeal.

“We’re now running just one waterline into the new room that breaks off into chillers. And there’s no tower,” Streff notes. “We just have two little 500-gallon tanks out back. When we shut down, there’s nothing to drain. And the Ecodry looks like a big radiator; it’s not up on the roof, so it’s easy to service. Our maintenance guy loves it.”

Streff also points out that with the Ecodry system in place, SK Plastics even has eliminated checking or cleaning the hydraulic heat exchangers when the company conducts its annual maintenance teardowns.

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161

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November 1, 2007
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LMT News

News of people and events important to the Lubrication Management community

LEBLANC ANNOUNCED AS NEW CEO OF GENERAC 
Waukesha, WI-based Generac Power Systems has announced the appointment of Edward A. LeBlanc as CEO of the company. He takes on this new position in light of former CEO William Treffert’s recent decision to retire from Generac after 31 years of service.

LeBlanc, who has more than 20 years of executive management experience in the industrial and consumer products sectors, has been serving as non-executive chairman of Generac’s board of directors for the past year. Immediately prior to joining Generac, he had been serving as president and CEO of the Residential and Commercial Division of Kidde, plc, a supplier of fi re protection equipment.

NYQUIST APPOINTED PRESIDENT EMERSON PROCESS GLOBAL SALES
Emerson Process Management has announced the appointment of Jim Nyquist as president of Global Sales. He will be directing sales operations for all company divisions (systems, software, instruments valves and services). In his 30-year career with Emerson, Nyquist has served in a number of world area roles in the Americas, Europe and Asia, including, most recently, as president of Emerson Process Management Europe.

BHATTACHARYA IS NEW PRESIDENT AT WONDERWARE 
Invensys plc has announced that Sudipta Bhattacharya is taking on a new role within the organization as president of the Wonderware business unit. Bhattacharya will report to Ulf Henriksson, CEO of Invensys. He replaces Mike Bradley, who had served as Wonderware president since November 2002. Bradley was instrumental in driving the company’s HMI and SCADA businesses, and then taking the company deeper into other manufacturing and infrastructure spaces.

JOHNSON CONTROLS BUYS CANADA’S THE CAPITAL GROUP 
Johnson Controls has announced its acquisition of The Capital Group, a mechanical services company headquartered in Ottawa, Ontario. Specifi c terms of the agreement were not disclosed. Founded in 1974, The Capital Group provides mechanical services for commercial and industrial customers throughout greater Ottawa. The company has approximately 82 employees.

FLIR ENTERS AGREEMENT TO ACQUIRE EXTECH INSTRUMENTS 
Extech Instruments has announced that the company’s president and owner, Jerry Blakeley, has entered into an agreement in which the stock of Extech will be acquired by FLIR Systems Inc. The transaction, which is subject to standard closing conditions, is expected to be completed within the fourth quarter.

According to Blakeley, the acquisition of his company creates new opportunities in distribution, product development and branding that will extend and strengthen Extech’s position in competitive markets. Known for its approach to product development, Extech has made extensive use of IR technology for both measurement and communication. The company holds fi ve patents incorporating IR into measurement instruments, and was the fi rst company to introduce a portable printer with IrDA wireless communication.

KAYDON CORPORATION ACQUIRES AVON BEARINGS 
Kaydon Corporation has announced that it has acquired Avon Bearings Corporation (“Avon”) in a cash transaction valued at $55 million. Avon is expected to add approximately $30 million to Kaydon’s fi scal 2008 sales. Headquartered in Ohio, Avon is a custom designer and manufacturer of high-precision large diameter turntable bearings. It also remanufactures bearings and sells replacement bearings. According to James O’Leary, president and CEO of Kaydon, this strategic acquisition is expected to help his organization accelerate growth in the wind energy arena, one of Kaydon’s major markets, while both strengthening existing customer relationships and adding others. In particular, he notes, the Avon addition will broaden Kaydon’s presence in important offshore crane, construction and steel markets for very large diameter bearings, while also providing access to the refurbishment market where Avon has built a leadership position over many years.

BENTLY CERTIFIED TO TEST FOR ULTRA LOW SULFUR DIESEL 
Bently Tribology Services (BTS) has announced that both of its labs (Peabody, MA and Minden, NV) are now EPAcertifi ed to test for ULSD (Ultra Low Sulfur Diesel).The EPA requires fuel marketers and all those in the supply chain to demonstrate an effective monitoring program to ensure compliance with new sulfur limits for both highway diesel, NRLM (Non-road, locomotive and marine) diesel and heating oil. BTS also offers full diesel and biodiesel fuel testing capabilities.

ATLAS COPCO LAUNCHES ITS FIRST SERVICE DIVISION Atlas Copco Compressor Technique is merging its customer service and spare parts operations into a dedicated service division. “By combining our service operations we will strengthen the cost competitiveness of the business and improve the service we give our customers,” says Ronnie Leten, president of Atlas Copco Compressor Technique. “This will serve to grow our aftermarket business and gives an increased focus also within the equipment divisions.”

The mission of the new Compressor Technique Service division is to be the global leader in customer service, providing all service of compressors needed by Atlas Copco customers, with an extended range of offerings. The gains from creating a single division include focused purchasing and the coordination of overlapping functions. The other operational divisions of Atlas Copco Compressor Technique are Industrial Air, Oil-free Air, Gas and Process, Portable Air and Specialty Rental.

According to the company, Atlas Copco has experienced increasing demand from customers to provide full packages of equipment, as well as service, training and spare parts. Atlas Copco’s business areas, Construction and Mining Technique and Industrial Technique, also have organizations in place for focusing on the service offering.

YOKOGAWA HELPS FOUND ISA SECURITY COMPLIANCE INSTITUTE Yokogawa has become a founding member the ISA Security Compliance Institute, an organization of industrial technology vendors and end users dedicated to establishing specifi cations and processes for testing and certifying control systems products.

The new organization will work to establish a set of wellengineered specifi cations and processes for the testing and certifi cation of security characteristics for critical control systems products.

Conformant products will carry the ISASecure designation, enabling suppliers to substantiate claims of compliance and provide asset owners with an independently validated identifi cation of compliant products when making procurement decisions.

Members, working with technical staff retained by the Institute, will develop a set of compliance requirements based on ISA99 security standards and other relevant standards, such as IEC or DHS recommendations. The program will be designed to cover everything from the device-level products up to gateway interfaces, to business planning and logistics systems.

FLUKE OFFERS INDUSTRIAL TEST TOOL EDUCATION GRANT 
Fluke Corporation will donate two of its high-performance Fluke 289 True-rms Industrial Logging Multimeters with TrendCapture to 10 qualifying educational institutions through a new education grant program. Designed to help ensure that educators, students and entry-level professionals have access to state-of-the-art technology, the program lets instructors in accredited programs apply for grants of the Fluke 289 for use in training students to diagnose problems in electronics, plant automation, power distribution and electromechanical equipment.

Members of the Fluke Education Partnership can apply for the grant by completing the application form available on the Partnership’s Website. The Partnership is a Webbased program offering educators in technical, university and apprenticeship programs free curriculum materials and a discount on all Fluke handheld test tools. Membership is free. Applications will be reviewed by a committee from Fluke for program elements, including breadth of course offering, degree/certifi cation qualifi cations and statistics, and plans for using the test tools within curriculum. The winners will be announced in February 2008.

FSA/HI MECHANICAL SEAL COURSE SET FOR 2008 MARTS 
The Fluid Sealing Association (FSA) (www.fl uidsealing. com) in conjunction with the Hydraulic Institute (HI) (www.pumps.org ), will conduct a pre-conference workshop entitled “Fundamentals of Mechanical Seals,” at the 2008 Maintenance & Reliability Technology Summit (MARTS), on Monday, April 14, in Rosemont, IL. Presented by instructors from FSA member companies, this comprehensive overview is crucial for those involved with the selection procurement, operation and/or maintenance of any equipment that utilizes mechanical seals—from new engineers to operators to maintenance personnel. Topics will include mechanical seal designs and arrangements; operating principles and application limits; seal chamber design and pressures; installation; environmental controls and piping plans; life cycle costing of mechanical seals and sealing systems; and troubleshooting. Attendees will receive a free copy of the authoritative HI/FSA book Mechanical Seals for Pumps: Application Guidelines (a $195 retail value) with their paid registration. For details, refer to the full MARTS brochure in this magazine or on www.MARTSconference.com. (EDITOR’S NOTE: Applied Technology Publications, parent of Maintenance Technology and Lubrication Management & Technology magazines and organizer of MARTS, is an affi liate member of the FSA.)

ASSOCIATION NEWS

SMRP CONFERENCE RECAP 
This year’s SMRP Fall Classic Conference, held October 7-10, 2007 in Louisville, KY, brought together record numbers of maintenance and reliability professionals and suppliers to the industry. According to conference organizers, more than 1000 attendees and 69 exhibitors took advantage of this year’s annual event and the professional development and networking opportunities it offered.

The Louisville gathering featured 50 technical presentations centered on the fi ve SMRP core bodies of knowledge, including business and management, manufacturing process reliability, equipment reliability, people skills and work management. A sixth track, SMRP initiatives and values, comprising an additional 12 presentations also was featured.

At the Annual Business Meeting, former vice chairman Tim Goshert was chosen to take Tom Byerley’s place as the chairman of SMRP in 2008. The SMRP Certifying Organization’s (SMRPCO) vice chair in 2007, Rich Overman, will serve as SMRPCO chairman for the 2008 term.

News that SMRPCO was approved as an ISO Accredited Certifying Organization by the American National Standards Institute (ANSI) on September 9, 2007 also was confi rmed. Since its fi rst exams in 2001, almost 2000 practitioners have obtained their CMRP certifi cation, including 281 in this year alone. Beginning January 1, 2008, the accredited exam also will be available as a computer-based test at more than 500 sites in the United States and Canada.

The SMRP Fall Classic was highlighted by another very special announcement regarding the establishment of a scholarship in honor of long-time, key SMRP and SMRPCO contributors Jack and Dorothy Nicholas. Known as the “Jack and Dorothy SMRPCO Scholarship,” it will be an annual award and offered to deserving students beginning in 2008.

For those planning early, next year’s SMRP conference is set for Oct. 20-23, 2008 in Cleveland, OH. For more information, visit www.smrp.org

YOUR NEWS IS OUR NEWS! 
OUR READERS WANT TO KNOW ALL ABOUT IT. 
SEND LMT NEWS ITEMS TO: jalexander@atpnetwork.com

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November 1, 2007
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From Our Perspective: Making Green By Going Green

 

ken_bannister

Ken Bannister, Contributing Editor

If you could simultaneously operate in a “greener environment,” assure increased capacity and save money, all with minimal effort, would you?

 

Who among us hasn’t seen—or heard of— one or more of the recent “scary” documentaries “An Inconvenient Truth,” “Crude Awakening” and “The Death of the Electric Car”? Who among us hasn’t formed an opinion on global warming, the Kyoto Accord on industrial emission reductions and high energy costs? Individually or collectively, these things have heightened our awareness of serious issues affecting industry’s future— and our own.

Many maintenance and reliability professionals I have spoken with over the past two years have begun developing a social conscience in regard to energy waste and pollution matters. Realizing, though, that a concerted effort is the only way to make a real difference in their operations, more than a few of these individuals have become quite frustrated by the absence of the vision and organization needed to get started down this path.

The “boon” years of the past three decades saw corporations making huge profits, in spite of themselves and their ineffective practices. These days, things are different. Global competitiveness has turned us all into savvy consumers who look for high-quality, rock-bottom-priced goods that are manufactured by “Green” suppliers. This new mindset is forcing companies to examine their production and maintenance operations and practices more closely than they once did, with an eye toward making them more effective, more energy efficient and more environmentally friendly— all at the same time.

With up to 70% of all mechanical failures directly and indirectly attributable to ineffective lube practices, implementation of a world-class lubrication management program is arguably the easiest and most effective improvement program in which a company can invest. Not only is such a program immediately effective in terms of increasing equipment availability, utilization and life cycle, when set up correctly it delivers considerable positive environmental impact through its contamination control and energy management components. Furthermore, such a program takes very little—if any—capital outlay to implement.

Environmental ROI 
From an environmental standpoint, a lubrication management program is a gold-plated change catalyst that pays off in many ways, including:

  • Reduced on-site inventories of lubricants through the lubricant consolidation process
  • Reorganized and cleaned-up lubricant storage areas with spill control management in place
  • Improved lubricant storage, handling and transfer methods, resulting in improved contamination and filtration control that significantly reduces lubrication system and equipment leakage
  • Reclamation and reuse of spilled lubricants

Energy ROI 
Energy management experts now recognize effective lubrication as a major strategy in energy reduction. Using the right lubricant in the right amount greatly reduces energy losses caused by friction. For example, a simple switch to a synthetic in a screw type compressor resulted in energy savings of 7.3%. A lubrication delivery system tune-up and change to a premium lubricant on a 500- ton straight side press resulted in 17.9% energy savings.* In each case, both equipment availability and lube change-out intervals increased.

These savings are not unusual—they’re typical. More importantly, with many corporate annual energy bills running into millions of dollars, these savings can translate into tens to hundreds of thousands of dollars annually. In fact, many lubrication program implementations now are being funded solely on energy ROI, with uptime and availability stated as a residual benefit!

Think about it. Isn’t time for you and your organization to go “Green?” Good Luck!

*Source: Energy Reduction Through Improved Maintenance Practices, Kenneth E. Bannister, Industrial Press, NY, 2006.

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504

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November 1, 2007
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Lube Cart Showcase

There is plenty to consider when acquiring a lube cart, including flow rate, filter type and viscosity
range, among others. Aside from their many options and customizable features, lube carts
offer the flexibility of portable—and convenient—filtration. That’s a “must have” capability in today’s fast-paced production environments. These pages highlight some of the latest, featurerich filter carts in the marketplace.

 

1107_techupdate_img1TRICO CORPORATION
Trico’s Gear and Lube Oil Filtration System eliminates the problem of filtering lubricants with viscosities greater than 500 SUS @ 100 F. Capable of filtering oils up to 10,000 SUS @ 100 F, it has a 4 gpm flow capacity. Fluid compatibility includes most petroleum-based oils, including hydraulic, gear, turbine, transformer and motor oils, among others. Ensuring that equipment receives the cleanest oil possible, as well as maintaining long element life and pump protection, four-stage filtration is provided. The Trico system also features differential pressure gauges that indicate when each of the filtration elements needs to be changed. Two sampling ports are included for safely sampling and monitoring the condition of the oil. The system is available in two models—a Hand-Held System and a Portable Cart System.

Trico Corporation 
Pewaukee, WI 
www.tricocorp.com

 

1107_techupdate_img2HY-PRO FILTRATION 
Hy-Pro offers a wide range of portable filtration systems for conditioning fluid before use, during transfer and while in the system. Designed for hydraulic and lower-viscosity lube oils, the FC series features two spin-on filters mounted in sequence for multiple combinations of particulate and water removal. The FCL (pictured) is designed around a large coreless, high-efficiency filter element and well suited for conditioning high-viscosity bearing and gear lubricants. A toploading housing provides ease of element service and minimal mess. Hy-Pro’s standard carts are available up to 22 gpm and any voltage necessary, including explosion-proof. True differential pressure gauges give an exact indication of element condition. Oil sampling ports are standard before and after the filter elements. Other options include pneumatic or hydraulic power and integrated particle monitoring.

Hy-Pro Filtration 
Fishers, IN 
www.filterelement.com

 

1107_techupdate_img3HARVARD CORPORATION 
Harvard’s filtration systems clean oils and water glycol fluids. Their unique depth-type filtration is capable of removing 0.5 micron particulates and water from oils down to 50 parts per million, and clean them to ISO 12/8/6 or better. Harvard’s filter systems can be made to order for diesel fuel, up to ISO 1000 viscosity. Also available are small handcarry systems with 1 gpm flow, wheeled carts with 20 gpm flow and optional bag filters, magnetic pre-filters, flow meters and particle counters. Customized systems can be ordered with flow rates of 200 gpm and a wide range of voltage requirements.

 

Harvard Corporation 
Evansville, WI 
www.harvardcorp.com

 

1107_techupdate_img4HYDAC TECHNOLOGY CORPORATION HYDAC Technology Corporation offers Single and Dual Stage Filter Carts to transfer and filter hydraulic fluids at rates of 7 or 14 gpm. The HYDAC OFCS and OFCD Series are compact, self-contained systems with high-efficiency, high-capacity filter elements capable of removing particulate contamination and/or water quickly, conveniently and economically. They are suitable for cleaning up existing systems and for pre-filtering new fluids. The OFCS single filtration unit can remove either water OR particulate contamination. The OFCD dual filtration unit can be used to remove both water and particulate contamination, or for staged particulate contamination removal.

HYDAC Technology Corporation Bethlehem, PA www.hydacusa.com

 

1107_techupdate_img5DES-CASE CORPORATION Des-Case offers users an economical way to customize their portable filtration needs. Two products from the FlowGuardTM line—filter carts and “drum toppers”—can be easily moved as needed/where needed to those applications that do not require constant filtration. The compact “drum topper” filtration unit allows you to take filters into tight places you couldn’t reach before. Weighing approximately 55 pounds, these drum-topper products are light enough to carry onto platforms and under equipment that cannot be reached with a traditional cart. All FlowGuard products can be custom-designed online. Customers can select from a variety of filters, flow rates, ports, connectors, adapters, hoses and colors to meet the specific needs of their application.

Des-Case Corporation White House, TN www.des-case.com

 

1107_techupdate_img6IFH GROUP, INC. IFH (Innovative Fluid Handling) Systems offers the E.S.P. mobile lube maintenance cart. Standing for “Efficient, Safe and Productive,” E.S.P. carts are available in more than 75 different variations. They feature a modular design that allows users to install different size containers on the same cart and use a different type of pump with each container. Users also can pull any cart off at any time and replace it with a different one. An E.S.P. cart can be created with any combination of containers, pumps, filters, meters, reels, storage space and more..

IFH Group, Inc. 
Rock Falls, IL 
www.ifh-group.com

 

1107_techupdate_img7KLEENOIL USA INC. 
Kleenoil’s Mobile Filtration Cart is a multi-purpose, fl uid cleaning and transfer machine for use with most hydraulic, gear, transmission and engine fl uids. The specially designed Kleenoil fi lter can achieve an ISO 4406 Cleanliness Code of 14/9, well below the original standards of the equipment’s original manufacturers and distributors. The Kleenoil cart will fi lter particles down to 1 micron, remove 99.95% of all water and minimize the amount of dirt and debris within a machine. As a result, repair and maintenance costs are reduced, greatly extending the life of engine and hydraulic equipment.

Kleenoil USA Inc. 
Plano, TX 
www.kleenoilusa.com

 

1107_techupdate_img8Y2K FLUID POWER, INC. 
Y2K Fluid Power offers several portable fi ltration systems with various functions, abilities and performance. Manufacturing in-house, Y2K always is designing new and customized lube cart models. Its new PT Series fi lter cart is an all-in-one portable oil tote and fi lter unit. It can be set up with a new oil tank or with new and used tanks with separate pumps to reduce contamination. This system can pump new or waste oils or serve as an off-line fi lter cart. A diamond-plate tool box and portable oil tray for storage of smaller containers also is available.

Y2K Fluid Power, Inc. 
Stacey, MN 
www.y2kfl uidpower.com

 

1107_techupdate_img9SCHROEDER INDUSTRIES 
Schroeder offers the Auto Flush Filter Cart (AFM) for staged particulate or water/particulate removal from hydraulic fl uid. The user-friendly AFM comes complete with the Schroeder Test- Mate Contamination Monitor® (TCM), making it easy for users to continuously monitor ISO levels in real time. A Siemens PLC provides an easy-to-use operator interface and an RS-232 port allows data to be downloaded to a PC. The AFM cart can run in either automatic or manual mode. Other options include a variable frequency drive and a water sensor that provides water saturation and temperature readings.

Schroeder Industries 
Leetsdale, PA 
www.schroederindustries.com

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465

6:00 am
November 1, 2007
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Bearings and lubrication for small steam turbines

If you ever have dealt with small steam turbines, chances are that issues of bearing selection and lubrication had to be addressed. Among these are issues of rolling element bearings vs. sleeve bearings, types of lubrication and application of lubricants. Even the definition of a turbine’s suitability for a certain service is often debated and using such terms as “General Purpose” and “Special Purpose” begs definition.

While a common differentiation of general purpose (GP) and special purpose (SP) steam turbines is indeed made at 1 MW, process industry users frequently have deviated from this rather arbitrary rule. Reliability professionals often have specified general purpose turbines if there were some spare capacity or if there were redundancy in the form of installed spares, or nonessential services, or moderate speed and so forth. A good example is a plant where there were several 2 or 3 MW GP steam turbines driving cooling water pump sets. Here, it would be very uneconomical—even wasteful—to insist on SP turbines.

Examples in the opposite direction exist as well. Take, for instance, a 600 kW steam turbine selected to drive a small, but essential, process gas compressor. In this situation, a special purpose steam turbine would be specified for very good reasons. It will cost more than the GP version, but it will have a lubrication system that makes it less prone to cause unscheduled outages.

Keep hybrids in mind 
Hybrids are a composite of GP practice and SP practice. Packaged systems may have to be upgraded by identifying the (potential) weak link(s) and specifying certain elements that are otherwise primarily associated with GP or, conversely, SP equipment.

Competent engineers frequently will specify hybrid support systems, such as lube oil consoles (Fig. 1), electronic governors, oil mist lubrication (Fig. 2) or oil flinger disks, instead of potentially unstable and risk-inducing slinger rings, etc. Even the rather customary carbon seal rings that have been supplied for seven or more decades with GP steam turbines are due for an upgrade. Forwardlooking users are now often replacing carbon rings with high-temperature mechanical seals and, in doing so, reduce both operating and maintenance expenditures.

Best judgment 
The best judgment of competent reliability engineers uses lots of experience and sound life-cycle cost assessments. The practices endorsed by these engineers often lead established industry practices and written standards by a decade.

Sound judgment recognizes that the life cycle of a machine is inevitably influenced by operating and maintenance practice. These practices have been the subject of thousands of written pages in books and articles. Moreover, they vary from location to location and are difficult to generalize across the board. While the practitioners may be disinclined to share this information, we nevertheless can observe what true reliability professionals do: They look at the specifics of each case and carefully weigh the alternatives. They will then submit their findings to responsible management in writing.

Lubrication frequency and oil analysis

Real-world questions… 
Questions on re-lubrication frequencies and how these are to be determined recently have been explored by some readers, as have issues relating to fitness for service or extending the life of existing oils. Of course, the major lube suppliers provide products and services—either directly or through contract distribution channels. They also offer lube oil analysis as part of the supply contract.

Some plant engineers seem to have engaged the services of major and minor suppliers without regrets, and they have pointed out reductions in both lube amounts and the number of different oil types being inventoried. One of our readers noted that his company is now using a single or a couple of oil types and maybe just one grease. “Yet,” he went on to write, “I’m not so sure this consolidation is the best way, as you could end up being held to ransom, and maybe not get the best properties of oil for expensive equipment. I would be interested to hear your opinion on this subject.”

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The same reader had looked at oil sampling valves and wondered which was best; he also noted copper greases were not to be used at his olefins site. He found two products that enjoyed name recognition and attempted to narrow it down to the best one. In terms of oil analysis sampling points, he opined that primary and secondary locations might be justified in some cases. Likening it to his analogous experience in vibration monitoring and analysis, he determined there was no need for “overkill of data” or complexity of the sampling system. “Data overload and complexity,” he stated, “might tend to become problematic and maintenance-intensive.”

Our reader pointed out, just as is the case with vibration analysis, that there is not the same need for detailed knowledge in all foreseeable instances. There are times when identifying the defective bearing component may be less important than simply knowing that the bearing should be replaced and determining the optimum time to effect the change-out. He indicated that component identification will obviously aid in finding certain root causes, and reliability engineers should strive to have a balanced approach.

Because the reader looked forward to our supplementary comments and thought his letter (and our answer) would be of interest to others, we are pleased to share this information.

 

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Real-world answers… 
Certainly, the bulk of this reader’s questions have been answered in many currently available books and articles. Without taking the time to go into more detail, the use of a single type of grease for all applications in a modern olefins plant will lead to two alternatives. To maintain reliability and on-stream time would defi- nitely require more frequent preventive maintenance. If this diligent maintenance effort is not expended, the plant will give up a measure of reliability. If, then, an equipment user in such a facility is willing to sacrifice equipment reliability and equipment run length, he might opt to use a single grease type. However, the one advocating a single type of grease should be asked about ultimate life-cycle cost of the machines so lubricated. If the advocate were to take the time to study life-cycle cost, he might find some surprise answers. If he does not take the time to study the matter, he’s just guessing and is thereby putting his plant at risk.

A similar statement could be made if an olefins plant had been persuaded to limit its oil types to just one or two. The probability of such a facility gaining Best-of-Class status is so close to zero that it is certainly not worth debating. Nevertheless, some consolidation of lubricants is feasible, as long as one looks at the lube requirements item-by-item and machine-by-machine. Sweeping generalizations are just that, i.e. sweeping generalizations are rarely adding value in a reliability-focused process plant environment. We are not familiar with the preferred brand of oil sampling valves. We are, however, reasonably familiar with some providers of oil analysis. Some folks advocate this predictive approach in situations where it makes absolutely no economic sense. The times and places and frequencies where sampling and analysis make sense are again discussed in many books and merit closer study. Having a preferred lubricant provider often is feasible and sometimes even beneficial. Unfortunately, there are also instances where this provider tries to sell the user too much stuff, or the provider’s representative is inexperienced or neglects a user’s account because he prefers to expend most of his energy finding new customers. There also have been instances where the lube provider does not offer the most suitable oil and then makes the user-buyer his test bed for trial-and-error solutions.

In summary, there will never be a substitute for the user educating himself/ herself on these issues. Whenever some users think training is expensive, we often ask them to calculate the expense with no training! Whenever they tell us they have no budget to purchase books, we leave them to do what they’ve become accustomed to accept as their normal routine: repair, repeat the repair, and repeat the repair again…

Contributing editor Heinz Bloch is the author of 17 comprehensive textbooks and over 340 other publications on machinery reliability and lubrication. He can be contacted directly at: hpbloch@mchsi.com

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6:00 am
November 1, 2007
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Part II: Oil Cleanliness: The Key To Equipment Reliability

Cleanliness can impact equipment life in a big way. For example, in hydraulic systems, with servo valves, a typical new unfiltered hydraulic fluid usually has an ISO cleanliness code of 25/22/19. The system requires a 16/14/11 based on pressure. By filtering the oil to the proper cleanliness level of 16/14/11, the life of the valve can be increased by four times.

As noted in Part I of this series, cleanliness is crucial to all equipment components—not just hydraulic equipment. In general, the tighter the clearances, the cleaner the fluid must be. Rolling element bearings have tight clearances with thin lubricant films. Table I illustrates rolling element life extension based on fluid cleanliness. Knowing that fluid cleanliness is important in equipment longevity, the next question is how clean does my fluid need to be and what kind of filtration is needed to achieve these levels.

Cleanliness targets The most sensitive components in a hydraulic are the directional control valves that usually dictate the cleanliness standards for the whole system. If only valve type and pressure conditions are known, a generalized ISO cleanliness code, as illustrated in Table II, can be used as a reference. Bearings also require clean fluids. ISO cleanliness requirements for bearings are shown in Table III.

Mike Boyd of Fluid Solutions has developed a simplified way of being more specific, based on equipment conditions, in determining system cleanliness requirements for both hydraulic systems and gearboxes. This simplified method can be seen in Fig. 1 and Fig. 2 (see page 10).

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Both Pall and HY-PRO filter companies have a method for calculating hydraulic system ISO cleanliness codes based on a large number of variables. Adapted from the British Fluid Power Association, a summary of this method is illustrated in Table IV.

Filtration requirements Selecting the most optimal cleanliness program requires the following:

  • Select the ISO cleanliness code to be achieved (previously discussed)
  • Select the correct placement for the filters
  • Select the correct filter sizing to achieve the desired cleanliness code

Hydraulic systems have a number of options on filter placement, including the three illustrated in Fig. 3. A fourth filter placement option with servo valves involves a control circuit filter placed just before the valves.

Cleanliness targets can be achieved with a pressure line filter alone or with a combination of various filter locations. As provided by HY-PRO, Table V notes the filter sizing to achieve various cleanliness codes with one filter containing a Beta ratio of 1000.

It must be must be emphasized that Table V is solely for illustrative purposes—and ONLY for HY-PRO filters. Each filter manufacturer has tables for its own cleanliness guidelines. Filter ratings based on the new test dust (>4μ, 6μ, 14μ) will be coarser for the same cleanliness code than the old test dust (>2μ, 5μ, 15μ).

Filter manufacturers use the Multi-Pass Filter Test to establish filter ratings in achieving cleanliness codes. (This test was discussed in Part I of this series.)

The Multi-Pass Filter Test is run at both constant and varying flow to simulate a hydraulic system as closely as possible. It can be run under many different conditions, including viscosity of fluid, amount of test dust added, flow rate, terminal pressure drop, etc. This testing is used to develop filter media to achieve different cleanliness targets. Because high levels of test dust are constantly added in the Multi-Pass Filter Test, high beta ratios compared to what is actually measured in the system are usually obtained. The same filter rated on an actual system may show a much

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lower efficiency. As an example, a filter on the Multi-Pass test rated at 6μ showed a beta ratio of 3000. When analyzed in the system, the actual beta ratio was only 3, but the cleanliness targets were met with the filter because a steady state condition had been reached in particle removal. Not many new particles were entering. The point here is that the way to evaluate filters is not strictly on beta ratios, but rather on how they perform in the system.

Achieving your requirements The most effective way to achieve your cleanliness code requirements is to optimize your filter placements and their size. The Parker Hannifin handbook is a particularly helpful reference in that it lists cleanliness requirements for various components and the filter requirements. As an example, for servo valves the handbook lists three different filter placement combinations: pressure, pressure & return line and pressure & offline. Many times, using a lower priced return line and/or offline filter will be more economical with the same results because a less expensive, coarser pressure line filter may be used. The four different filter options are as follows:

Pressure line filter…

  • High cost
  • Protects sensitive components downstream of pump
  • Sees total system flow
  • Bypass options

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Control circuit filter…

  • Directly before sensitive valve and
    will only filter fluid to that component
  • Protects sensitive valves
  • Cost effective when used in combination
    with return and/or offline filters
  • High collapse option

1107_contaminant_img5Return line filter…

  • Typically sees total system flow at low pressure
  • Cleans ingressed and generated contaminants
  • Low cost to weight of dirt removed

Offline filter…

  • Low pressure
  • Constant flow
  • Capable of optimizing system at low cost
  • Filter changed without system interuption

The impact that various filter options can have on a system can be seen in the following example. Here, a hydraulic system was using a 3μ control circuit filter and a 10μ return line filter. By changing to a 3μ return line filter, the particles >4μ were reduced tenfold and the control circuit filter could have been changed to a coarser grade to achieve the same previous cleanliness target.

Conclusion
The key to any reliability-based program is to develop a successful cleanliness control program. This is done by minimizing contaminant ingression through a cost-effective filtration program based on the following criteria:

  • Setting of cleanliness requirements based on objectives and equipment type
  • Selection of optimum filter placements
  • Selection of filter sizing

Utilize your filter manufacturers in evaluating your systems and building the cleanliness control program(s) to meet your requirements.

Coming up next time 
The final article in the series will present case histories on the economics of effective filtration programs.

Acknowledgments:
The author thanks HY-PRO, Pall and Parker Hannifin for providing useful information for this article. Particular thanks go to Mike Boyd of Fluid Solutions for his mentoring on filtration principles and providing valuable information.

(Editor’s Note: In Part I of this series— Sept./Oct. 2007, pgs. 34-38—Fig. I and Fig. II were provided by Parker Hannifin. They were referenced incorrectly, and we regret the oversight.)

Contributing editor Ray Thibault is based in Cypress (Houston), TX. An STLE-Certified Lubrication Specialist and Oil Monitoring Analyst, he conducts extensive training in a number of industries. E-mail: rlthibault@msn.com; or telephone: (281) 257-1526.

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November 1, 2007
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Going Where Others Can't

As a number of Louisiana refineries are finding, flexible sensor technology can deliver an especially cost-effective way to measure temperatures almost anywhere in a system.

As a systems integrator that services refineries and chemical plants in Louisiana, we have found our customers’ biggest maintenance headaches come in the area of temperature sensor replacement. Rigid temperature sensor technology, used inside thermowells for 20-50 years, is the nightmare of every maintenance department. Problems using rigid sensors include stocking difficulties, finding suitable replacements, ordering the correct length and size, and being unable to install a replacement sensor in an existing thermowell.

Flexible temperature sensors, on the other hand, offer a universal solution for all maintenance dilemmas. A flexible sensor fits nearly everywhere, can be cut to the correct length and reduces the number of spare parts a plant has to keep on hand.

1107_flexsensor1Rigid sensor challenges
A standard rigid temperature sensor, made by virtually every sensor manufacturer in the world, consists of a sensor element—thermocouple (T/C) or Resistance Temperature Device (RTD)—protected inside a rigid stainless steel shaft in a 2” sensitive area, forming what most users know as a “fixed length sensor” (Fig. 1). These fixed length sensors are either spring loaded (for use with thermowells), welded to a hex nipple for a fixed immersion length into a process or sealed with epoxy, exposing the sensor leads for external measurement connections.

Typically, the T/C or RTD element is embedded inside the bottom two inches of a stainless steel tube, which is then filled with mineral insulated powder (MGO) and sealed with epoxy to prevent moisture penetration. The rigid sensor assembly fits into the thermowell beneath the connection head. The wires from the sensor are then terminated in the enclosed head and connected to extension wires using a terminal block, or attached directly to a transmitter. Wiring is then run back to the control room, usually encased inside conduit for long wire runs.

The first problem posed by rigid sensors is the difficulty involved in replacing a faulty sensor. Typically, a maintenance technician has to remove the enclosure cap, disconnect the wires from the transmitter or terminal block, disassemble the union, conduit and fittings attached to the transmitter and thermowell, and then move them out of the way before he or she can pull the rigid sensor out of the thermowell. Depending on the age of the installation, the corroded conditions of the conduit or junction, and the amount of room available, this can be an arduous task, particularly on the top of towers or columns, or in close confinement areas.

The next problem involves determining the correct length of the replacement sensor. In many cases, a maintenance technician may know that the sensor needs to be replaced, but doesn’t know the exact length of the rigid sensor. If the loop is critical, the plant may not want to pull out the old sensor yet. Instead, they will make all the necessary measurements first, order a new sensor and wait for it to arrive. In that case, the technician will have to make multiple visits to the sensor—first to determine as much information about the installation as possible, including sensor type, connection style (nipple union nipple, direct thread, lagging length, approximate insertion length, etc.)—and then go back to stores to try to find a best fit, probably returning with a number of different sizes to avoid a third trip. Of course, the unused sensors then have to be returned to stores (another trip)!

In some cases, the technician leaves the old system intact, gets on the phone to a sensor representative, and the two of them make an educated guess based on a thermowell’s length, size of the union, length of nipples, etc. At least one sensor manufacturer we deal with admits that they only get it right about 85% of the time when they have to guess. Another solution is for a maintenance tech to carry 8-10 spare sensors out into the plant, in hopes that one of them will be the right size. All this could be avoided, of course, with proper documentation—that is, the size and type of each temperature sensor should be recorded for future reference when replacements are needed. This, however, can be a daunting task, considering that some plants have hundreds, if not thousands, of temperature sensors. Plus, engineering drawings do not always represent the “as built” installation.

1107_flexsensor2Once a replacement sensor is found, ideally it will slide back into the thermowell. Unfortunately, thermowells can cause other problems. Some thermowells will “sag” (bend) when exposed to high temperatures over prolonged periods, as is the case with flare stacks (Fig. 2). It may be possible to extract the existing sensor from a sagging thermowell, but it is usually impossible to install a new rigid sensor into a sagging thermowell. Instead, the thermowell itself must be replaced.

Thermowells also can accumulate debris, which makes it difficult to install a new replacement sensor. In areas with high humidity, such as Louisiana and other southern states, thermowells can fill up with assorted contaminants that condense out of the air. When the rigid sensor is removed, this debris can then prevent a new sensor from being fully inserted back into the well.

Finally, the length of a rigid sensor can affect accuracy of the measurement: A rigid sensor inside a short, 2”-3” thermowell may not be measuring the correct process temperature. This is because a sensor with a rigid metal sheath is not measuring just the process inside a short thermowell; some of the sensor’s sheath protrudes up into the nipple, union or enclosure, which is outside the process. Such a sensor actually measures part of the process temperature and part of the ambient temperature outside the process. This situation typically will result in erroneous temperature readings with possibly adverse effects on process control. In one case at a tire plant, the lower inaccurate reading resulted in higher process temperatures that, in turn, caused the thermowells to overheat and sag. Sagging thermowells resulted because the actual temperature was much higher than the sensor could record.

1107_flexsensor3Flexible solutions
Even if an application spec calls for a rigid sensor, a flexible sensor can fill the requirement. A flexible sensor typically consists of a 1” stainless steel sensor element and lead wires that are protected either with Teflon or fiberglass insulation. Flexible sensor wires can be trimmed to the correct length depending on assembly (Fig. 3).

The sensor element is held in place with a spring at the top of the thermowell (Fig. 4). The spring keeps the sensor in constant contact with the bottom of the thermowell, allowing the best heat transfer to the sensor. If there are large open areas within the union/nipple junction, spacers can be used to facilitate insertion through these areas.

Replacing a flexible sensor in the field is much simpler, compared to rigid sensors. To insert a new flexible sensor in place of an existing one, a technician only has to remove the cap, disconnect the sensor wires, remove the transmitter or terminal block and pull out the old sensor. It is not necessary to disassemble the union, conduit or any other fittings.

 

1107_flexsensor4Because a flexible sensor can be trimmed to the correct length, a technician only has to carry a single sensor to the field. Flexible sensors typically are available in various lengths to accommodate nearly every size of thermowell or application a plant may have.

In the case of a sagging thermowell, if the rigid sensor can be removed, a flexible sensor can be installed without replacing the old thermowell. We usually purchase flexible sensors that are slightly smaller in diameter than rigid sensors. The most popular rigid temperature sensors built in the U.S. have a ¼” (0.25”) O.D. metal shaft. Most thermowells installed today have a 0.260” internal bore (in Europe a 7mm bore is used). We order flexible sensors with a 6mm O.D. (slightly smaller than 0.25”), making it easier to slide into a sagging well or into dirty thermowells that have built-up or caked-on debris inside them.

Because a flexible sensor has a 1” sensor with flexible fiberglass or Teflon insulated lead wires and a spring, it can be trimmed to fit even the smallest of thermowells. Furthermore, since the spring and lead wires cannot conduct ambient temperatures to the sensor, outside measurement errors cannot exist. Like the previously mentioned tire plant, we’ve had several applications on other flare stacks where we installed flexible sensors and the process engineers were surprised to see that their stacks were operating at much higher temperatures than the previous rigid sensors had indicated. The energy and fuel cost savings obtained from operating these stacks at the proper temperatures paid for the replacement sensors many times over.

Intriguing applications
Flexible sensors offer several interesting ways to approach temperature measurement applications and their problems. For example, the intense humidity in Louisiana causes “Green Rot” at the wire termination points with thermocouples, so engineers and technicians try to avoid as many termination points as possible. Because a flexible sensor can be made with any length of wire, we now have several plants in the area that do not use terminal blocks anymore; instead, the wires are run directly to temperature transmitters located in a separate cabinet. The sensor wires are run inside rigid or flexible conduit, all the way from the thermowell to the remote mounted transmitter, without using any intervening termination blocks. This eliminates one major source of failure.

Another plant noted that since the sensor wire did not carry any dangerous voltage or current, it was not necessary to encase it inside conduit. Therefore, all their sensor cables run directly from the thermowell to a remote transmitter without conduit (Fig. 5). The flexible insulation covering the sensor wires is sufficient to protect it from most environments, but stainless steel braid or flex armor can be added at very little cost.

In one application, a plant had a burner with dozens of temperature sensors, but none could be replaced without shutting down the entire burner. It was simply too hot for a tech to walk into the burner while it was operating. By using flexible sensors inside long protection tubes attached to the points of measurement, it was possible to slide a flexible sensor in and out of the tube from a safe location without shutting down the burner.

In a similar situation, a refinery had a problem with calibrating and replacing sensors with transmitters on top of columns or towers. It was physically dangerous for a tech to climb to such heights while the hot process was running, and try to safely work with rigid conduit, fittings and transmitters. This refinery replaced all its rigid sensors with flexible units and installed the transmitters at the bottom of the towers for easy access. Again, because a flexible sensor can be made to any wire length, the transmitter could be calibrated or replaced from the bottom of the tower, and the flexible sensors were easier to change out if they failed.

Adding up the savings
Over the last year, several refineries in Louisiana have begun systematically replacing all their rigid temperature sensors with flexible sensors because of the cost savings they expect to gain.

  • Maintenance will be easier, take less time and cause fewer shutdowns or process interruptions.
  • Fewer thermowells will have to be replaced because of sagging or foreign debris that clogs the wells.
  • Only two or three standard sensor lengths will be needed for an entire plant, reducing the spare parts inventory.
  • The refineries will get better measurements in shorter thermowell applications, leading to increased accuracy and energy savings.

Although conventional rigid temperature sensors have proven to be a workhorse for the past 50 years, modern flexible sensors are now starting to replace them across Louisiana.

Robert Poole is an engineer with Process Measurements & Monitors, in Baton Rouge, LA.

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