Understanding & Solving Heat Transfer Equipment Stall

Heat transfer loop

Stall can most easily be defined as a condition in which heat transfer equipment is unable to drain condensate and becomes flooded due to insufficient system pressure.

Stall occurs primarily in heat transfer equipment where the steam pressure is modulated to obtain a desired output (i.e. product temperature). The pressure range of any such equipment ( coils, shell & tube, etc....) can be segmented into two (2) distinct operational modes, Operating and Stall.

Operating: In the upper section of the pressure range the operating pressure (OP) of the equipment is greater than the back pressure (BP) present at the discharge of the steam trap. Therefore a positive pressure differential across the trap exists allowing for condensate to flow from the equipment to the condensate return line.

Stall: In the lower section of the pressure range the operating pressure (OP) of the equipment is less than or equal to the back pressure (BP) present at the discharge of the steam trap. Therefore a negative or no pressure differential exists, this does not allow condensate to be discharged to the return line and the condensate begins to collect and flood the equipment.

You can read the entire Armstrong technical paper below.

Visit this link to download your own copy of Armstrong Fluid Handling: Understanding and Solving Equipment Stall.

Understanding & Solving Heat Transfer Equipment Stall from Mead O'Brien, Inc.

Applying the ASCO 212 Composite Solenoid Valve for Reverse Osmosis Water Systems

ASCO Series 212 Composite Solenoid Valves
for Reverse Osmosis Water Systems

Reverse osmosis (RO) is one of the most popular methods for effective water purification. It has been used for years to purify contaminated water, including converting brackish or seawater to drinking water.

Reverse osmosis is a process in which dissolved inorganic solids (such as salts) are removed from a solution (such as water). This is accomplished by pushing the water through a semi permeable membrane, which allows only the water to pass, but not the impurities or contaminates.

Reverse Osmosis can deliver bottled-water quality safety and taste by removing over 99% of dissolved minerals, chlorine and contaminants. Many leading bottled-water companies actually use large-scale RO to produce their water.

Reverse osmosis systems are found in several drinking water applications from restaurant, food and beverage equipment to grocery store produce misting.

The ASCO Series 212 solenoid valve is designed for these type systems. The valves come with NSF approvals for use in drinking water systems and also is design with unique “FasN” quick connection system. The valves are designed to handle 150 psi up to 180 deg. F. and has low wattage coils in both AC and DC.

See the video below for an illustration of where these valves are used in RO systems.

Foxboro Vortex Flow Meters

The patented family of Foxboro vortex flowmeters has the high accuracy and rangeability of positive displacement and turbine flowmeters without the mechanical complexity and high cost. Maximum rangeability up to 100:1 is possible as compared to 3:1 for a nonlinear differential pressure producer (orifice plate).

Because these Flowmeters have no moving parts, they are very durable and reliable. This simplicity of design ensures low initial cost, low operating and maintenance costs, and therefore contributing to an overall low cost of ownership.

For more information, contact:

Mead O'Brien

(800) 892-2769

www.meadobrien.com

Traps for Sour Gas Service

Armstrong Series 300

What is “sour gas”? 

In the oil and gas industry, “sour gas” refers to natural gas that is contaminated with hydrogen sulfide (H2S or “sulfide”). “Sour crude,” similarly, is crude oil that contains hydrogen sulfide. These are naturally occurring conditions, but definitely not desirable. Aside from the environmental pollution problems with “high-sulfur” fuels, there are some serious corrosion problems that can affect many materials. Liquid drainers (drain traps) and strainers are the most common Armstrong products ordered for sour gas service. A few other products are sometimes specified, notably inverted bucket air traps. An inquiry may be accompanied by an extensive specification of H2S concentrations; there may be a line indicating “Sour Gas Service;” or may only be the note “NACE.” This is a reference to Standard MR0175-93 published by the National Association of Corrosion Engineers (NACE).

What is the problem? 

H2S under pressure permeates into the crystalline structure of the metal and strains the structure of the crystal. This reduces its ability to deform in a ductile manner. The net effect is to make the material brittle. In the presence of external stresses due to applied pressure or loads, or internal stresses due to cold working or welding, parts may fail by cracking without any warning. This process is called Sulfide Stress Cracking (SSC). SSC is affected by many parameters, including: · Composition, strength, heat treatment, and microstructure of the material; · Hydrogen ion concentration (pH) of the environment; · Hydrogen sulfide concentration and total pressure; · Total tensile stress; · Time and temperature. Choice of products and their limitations. Inverted bucket traps (primarily for air trap service) should be selected from the Series 300 traps. The bucket and mechanism (except valve and seat) will be annealed to eliminate the locked-in stresses from the stamping operations. The valve and seat will be made from Type 316 stainless, without additional heat treatment. Cast iron bucket weights are permitted, since they are not stressed in tension. Special bolting is required only if the sour environment is also outside the trap.

Download the Sour Gas Trap Selection Guide Here

Mead O'Brien VP Elevated to ISA Fellow

ISA Fellows 2016

The International Society of Automation (www.isa.org) is a nonprofit professional association that sets the standard for those who apply engineering and technology to improve the management, safety, and cybersecurity of modern automation and control systems used across industry and critical infrastructure. It currently boasts 40,000 members worldwide.

Steve Huffman

Elevation to the distinguished grade of ISA Fellow is granted to Senior Members in recognition of their exceptional engineering scientific contributions to the field of automation.

Steve Huffman, VP of Sales and Marketing at Mead O'Brien will be one of the honorees at the 54th Annual ISA Honors & Awards Gala to be held on 24 September 2016 in Newport Beach, California.

Steve is being recognized for leading the effort to create the US Department of Labor’s Automation Competency Model for automation professionals.

Congratulations to Steve for this achievement and for his many years of service to the instrumentation and automation community.

Your Career in Process Automation May Just Save The World

Did the title get your attention?

Here's a thesis for you to consider: People entering the workforce who are interested in meaningful careers should strongly consider industrial control and automation.




Wouldn't you like a career where you could:

• Help solve world energy
• Help provide clean water
• Help solve world hunger
• Help clean and sustain the environment
• Help meet chemical & mineral needs
• Help provide material goods

It's a bold statement, but there's truth that engineering careers in manufacturing automation will contribute to the solutions of some of the world's most significant challenges.

The following presentation by Steve Huffman, Vice President of Mead O'Brien and Chairman of Government Relations for the Automation Federation, provides an interesting argument about the importance of people in the changing world of process automation. Enjoy.

Automation in Industry: The People Make the Difference! from Mead O'Brien, Inc.

A Guide to Instrumentation for Ethanol Fuel Production

Ethanol plant

Ethanol, the common name for ethyl alcohol, is fuel grade alcohol that is produced through the fermentation of simple carbohydrates by yeasts. Fueled by growing environmental, economic, and national security concerns, U.S. ethanol production capacity has nearly doubled in the past six years, and the Renewable Fuel Association (RFA) projects another doubling of the industry by 2012. Ethanol can be made from renewable feedstock’s such as grain sorghum, wheat, barley, potatoes, and sugar cane. In the United States, the majority of the ethanol is produced from corn.

The two main processes to produce ethanol from corn are wet milling and dry milling.

Foxboro transmitter

Wet milling is more versatile as it produces a greater variety of products, including starch, corn syrup, and sucralose (such as Splenda®). However, with this versatility come higher costs in mill design, building, and operation. If ethanol is the primary product produced, dry mills offer the advantages of lower construction and operations costs, with improved production efficiency. Of the more than 70 U.S. ethanol plants currently being built, only a few are wet mills.

The efficiency of ethanol production has come a long way during the last 20 years. As more large-scale facilities come on line, ethanol producers are faced with the growing challenge of finding innovative ways to maintain profitability while this market matures. An increasingly accepted solution is process automation to assist ethanol producers in controlling product quality, output, and costs. Because sensing and analytical instrumentation represents what is essentially the eyes and ears of any automation system, careful evaluation of instrumentation, at the design phase can reduce both equipment and operating costs significantly, while improving overall manufacturing effectiveness.

The following document, courtesy of Foxboro, provides a good overview of instrumentation and the production of ethanol.

A Guide to Instrumentation for Ethanol Fuel Production from Mead O'Brien, Inc.