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Everything listed under: Vacuum Breaker

  • Test Your Knowledge: Which Device Is It?

    Which of the following helps minimize water hammer, helps drains condensate, and minimizes temperature swings?

    1. Inverted Bucket Steam Trap
    2. Vacuum Breaker
    3. Fluid Air Coil
    4. Mechanical Condensate Pump
    5. Pilot Operated Regulating Valve

    And the answer is...


    2. Vacuum Breaker

    A Vacuum Breaker is a simple, reliable device that allows air to enter a steam piping system when a vacuum is induced. When a steam system shuts down, the remaining steam condenses into water, which takes up a much smaller volume than the original steam. This creates a vacuum, which can lead to water hammer and tube damage if not relieved of in a timely way. 

    Check out this video which shows the proper use of a vacuum breaker in a steam system.


    Here are our top 4 reasons for including a vacuum breaker in your system:

    1. It helps allow for complete condensate drainage under all operating conditions: on/off or modulating applications. 
    2. It helps minimize water hammer. 
    3. It helps minimize temperature swings and uneven temperatures. 
    4. It helps minimize product waste.

    All heat transfer components, whether shell-and-tube exchanger, plate-and-frame exchanger, air heating coil or any other device, require vacuum breakers. As the video shows, because the condensate piping after our coil is clear glass, you can watch condensate backing up into the coil without a vacuum breaker.  Once the vacuum breaker is allowed to operate, the coil can remain free of condensate under all operating conditions, which eliminates many issues that can shorten equipment service life and/or cause operation problems.

    The footage for that video was taken in our Steam Training Room located in Minnetonka, Minnesota, where we have regular training classes.  We utilize a steam boiler, glass piping, and functional glass-bodied steam traps to describe and demonstrate a variety of steam basics and advanced concepts in the 4 main areas of a steam system: Generation, Distribution, Utilization, and Condensate Return.

    Contact us for more information on the proper use of vacuum breakers or sign up for our Steam Energy Conservation seminars to learn more. 

     


  • Coping With Vacuum – The Importance of Ejector Systems in Urea Plants

    The following article was recently published by Jim Lines and appeared in the June 2017 issue of World Fertilizer magazine. 

    Ejector systems are critical to the final concentration of a urea solution. Regardless of the end product, whether produced by granulation or prilling, ejector systems establish evaporator pressures that permit the removal of water to concentrate the urea solution at temperatures sufficiently low enough to minimize biuret formaton. 

    There are several process technologies for urea production. Saipem/Snamprogetti, Maire Tecnimont/Stamicarbon, Toyo Engineering Corp., Casale and NIIK offer the most frequently used. For each process technology, the ejector systems are critical to plant throughput and product quality. While critical to the success and profitability of a urea plant, ejector systems are viewed as not generally well understood. The thermodynamics of ejector performance in not widely known and the vacuum condensers within an ejector system cannot be designed with conventional heat exchanger software. 

    This article provides a deeper review of ejectors and vacuum condensers in urea concentration processes so that specifiers, evaluators, purchasers and users of this critical process equipment understand the salient considerations necessary to provide reliable plant performance. Download the complete article that covers:

    • Ejector systems for urea concentration processes
    • Steam supply conditions
    • Ejector performance curve
    • Variables that affect ejector performance
    • Booster ejector flushing
    • Vacuum condensers
    • Ammonia emission from ejector system
    • Numerous charts and equations

    Click to download the complete article "Coping With Vacuum" by Jim Lines, Graham Corp. 


  • Top 4 Reasons For Including A Vacuum Breaker In Your Steam Utilization Piping Practices

    A Vacuum Breaker is a simple, reliable device that allows air to enter a steam piping system when a vacuum is induced. Here are the top 4 reasons for including a vacuum breaker in your system:

    1. It helps allow for complete condensate drainage under all operating conditions: on/off or modulating applications. 
    2. It helps minimize water hammer. 
    3. It helps minimize temperature swings and uneven temperatures. 
    4. It helps minimize product waste.

    So where do you install a Vacuum Breaker in your steam system? 

    It is generally recommended that all heat transfer devices have a vacuum breaker installed at points designated by the heat transfer manufacturer. The normal locations are after the control valve, usually on the top portion of the heat transfer device, and always above the steam trap inlet (see illustrations).

    All heat transfer components, whether shell-and-tube exchanger, plate-and-frame exchanger, air heating coil or any other device, require vacuum breakers. Click here to see a demonstration video of a typical steam air heating coil with modulating pressure in our Steam Training Room.  Because the condensate piping after our coil is clear glass, you can watch condensate backing up into the coil without a vacuum breaker.  Once the vacuum breaker is allowed to operate, the coil can remain free of condensate under all operating conditions, which eliminates many issues that can shorten equipment service life and/or cause operation problems.

    The footage for that video was taken in our Steam Training Room located in Minnetonka, Minnesota, where we have regular training classes.  We utilize a steam boiler, glass piping, and functional glass-bodied steam traps to describe and demonstrate a variety of steam basics and advanced concepts in the 4 main areas of a steam system: Generation, Distribution, Utilization, and Condensate Return.

    Contact us for more information on the proper use of vacuum breakers or sign up for our Steam Energy Conservation seminars to learn more.

  • Vacuum Breaker Check Valves: Your Defense Against Pipe Collapse & Pressure Vessel Damage

    Vacuum Breaker Check Valves provide a defense against collapsed pipes and damage to pressure vessels, which can be found in processes requiring heated fluid or gas retention and distribution. In DFT's ebook "Vacuum Breaker Check Valves: Your Defense Against Pipe Collapse & Pressure Vessel Damage", they address the following topics:

    • Effects of cooling on thin-walled closed systems 
    • Design components
    • Maximum pressure identification
    • And more

    Understanding your closed heated system, as well as the types and temperatures of fluids and gases is essential to preventing implosion damage. Learn more about using Vacuum Breaker Check Valves clicking the image to download the ebook or contacting Campbell-Sevey.




  • What Causes Steam Coils to Fail?


    Steam coils are a cost effective way to heat air. Costly premature failures can occur for a number of reasons, which leads to the purchase and installation of replacement steam coils. Usually this occurs at inopportune times and can lead to emergency service and overtime. Here are the five primary reasons steam coils fail:

    1. Erosion

    Over time, internal erosion can take place inside the coil at tubes and headers. This erosion is caused by two factors, poor steam quality and internal steam velocity.

    Steam quality (or dryness fraction) is defined as the percentage of gaseous steam in a pound of steam. The more liquid it contains, the worse the quality. Some steam boiler manufacturers will guaranty steam with a quality of 99.5%. That's 99.5% steam and 0.5% liquid, usually in the form of very small droplets. Though it may leave the boiler very dry, by the time it gets to the point of use, like a steam coil, it may have degraded to 80% dry or worse. If you could see inside the piping, you might see a fog traveling down the pipe with a stream of condensate running down the bottom of the pipe. Poor planning, poor piping practices, and/or failed steam traps are typical causes for steam quality degradation.

    Once these droplets enter the steam coil, they literally wear out the metal parts that are in their path, just like a sand blaster. If the coils are not designed well, the internal steam velocities can be high, making this situation worse.

    We at Campbell-Sevey have developed solutions for poor steam quality and can design steam coils around acceptable internal steam velocities to lengthen coil life.

    2. Corrosion

    When non-condensable gasses are allowed to remain inside steam coils, oxidation and carbonic acid corrosion can occur. Carbonic acid forms when carbon dioxide dissolves in water (condensate). The cooler the condensate and/or the higher the steam pressure, the worse the effect. Localized pH's of 3 are possible, which is quite acidic and dissolves the pressure containing metals of the coil. Pin-hole leaks start to develop over time. The use of thermostatic air vents and proper piping is critical to the removal of these gasses.

    3. Freezing

    Why does freezing occur? Steam in the coil turns to water (condensate) as it gives up heat. Once condensate is formed it must exit the coil before the freezing air on the finned side can extract enough additional heat from the water to turn it to ice. Unfortunately, installers and designers sometimes fail to recognize the factors which cause condensate to remain in the coil.

    Freezing occurs when condensate isn’t allowed to drain with freezing air temperatures blowing across the face of the coil. Proper steam coil installation planning, piping, trapping, and condensate return are critical for freeze prevention.

    4. Improper Coil Selection

    Not every coil is designed to work with every system. Sometimes the coil is not designed for the performance, and sometimes the coil is not designed for the duty. Conventional copper tube coils are usually adequate for low pressure steam commercial heating installations; however, industrial heating and process applications demand the most rugged possible coil construction.

    Adding additional surface area beyond what is required is not always the best solution. This can lead to decreased steam pressures in the coil and possibly unnecessary cooling of condensate, causing corrosion.

    For most coil replacements, Campbell-Sevey's field technicians first identify what caused the failure and then work with the design staff and our manufacturers to determine the best approach to increase the performance and life of the coil.

    5. Improper Installation

    If you have the right coil, but it isn't installed properly it is destined to fail. Here are several of the most common installation issues that occur:

    • The Coil is Not Pitched Toward the Return Main

    Since gravity is a main force used to drain condensate, pitching the coil toward the return main can be critical factor in getting the condensate out quickly.

    • No Vacuum Breaker Installed 

    Without a vacuum breaker, modulation of the steam valve causes a vacuum to form, so that the pressure in the coil is less than the pressure in the condensate main. Condensate will not drain, so the coil will begin to flood. This can cause freezing, corrosion, and/or water hammer.

    • There is Either No Drip Leg or a Drip Leg of Insufficient Height 

    When the steam control valve modulates sufficiently, the only available pressure to force condensate past the strainer and trap is the static head of the condensate in the drip leg. A short drip leg may reduce the trap capacity to the extent that the trap cannot keep up with the condensate loading, so flooding takes place.

    • Insufficient Trap Capacityor Wrong Trap is Used 

    Knowing that much of the time there is only head pressure to remove condensate, the steam trap orifice size selection becomes critical. It must be of sufficient size to remove all condensate generated by the coil, plus safety factor, at the pressure differential determined by the drip leg. The maximum operating pressure rating of the steam trap must be determined by the safety relief valve set pressure of the steam supplying the coil. If either of these factors is not taken into account, the wrong trap could be installed and the coil could fail.

    Selecting the proper steam trap style is also important to ensure that that the coil operates at peak performance. We offer and stock many steam trap styles and will recommend the proper style for your application,

    • The Condensate Return Line Rises Above the Steam Trap Outlet

    Some system designers contend that condensate will be lifted by steam pressure. While this may be true at the full load conditions, at part load conditions not enough pressure exists at the steam trap to lift condensate. The result is coil flooding with condensate.

    Consult with Campbell-Sevey

    For proper operation, all steam coils require additional equipment, such as control valves, steam traps, thermostatic air vents and vacuum breakers that will increase the performance and the life of the coil. When combined with the proper equipment and correct installation your coils can last for many years. At Campbell-Sevey, our experts understand the interplay among these pieces of equipment and how each affects the others. We size them all, we select them all, and we show you how they should be installed. We look at the past failures and use that information to make recommendations for improvements for the future. We look upstream and downstream of the coil, from steam supply to condensate return, to make recommendations to increase overall system efficiency and effectiveness. We understand these 5 pitfalls and how to avoid them.

    Both Industrial heating and process applications demand the most rugged possible coil construction. Campbell-Sevey offers a wide selection of coil construction and materials from light duty comfort heating to heavy industrial and utility grade and we have the expertise to know when to use each type.

    Consult with the steam, air and water experts at Campbell-Sevey to choose the right equipment for your steam coil applications.

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Products We Carry

GENERATION
  • Hot Water Boilers
  • Watertube Steam Boilers
  • Firetube Steam Boilers
  • Deaerators
  • Heat Recovery Steam Generators (HRSG’s)
  • Automatic Recirculation Valves
  • Economizers
  • Gas-Fired Water Heaters
  • Gas-Fired Humidifiers
  • Boiler/Generator Flue Stacks
  • Continuous Emissions Monitors (CEMS)
DISTRIBUTION
  • Pressure Reducing Valves
  • Safety and Relief Valves
  • Control Valves
  • Pressure Independent Control Valves
  • Expansion Joints, Guides, Anchors
  • Flash Tanks
  • Flow Meters
  • Balancing Valves
  • Check Valves
  • Separators
  • Pumps
  • Pressure Booster Systems
  • Piston Valves
UTILIZATION
  • Heating/Cooling Coils
  • Plate and Frame Heat Exchangers
  • Shell and Tube Exchangers
  • Water Heaters
  • Steam Humidifiers
  • Vacuum Systems
  • Condensers
  • Steam Traps
  • Wireless Steam Trap Monitors
  • Tube Bundles
  • Direct Gas-Fired Space Heaters
  • Direct Gas-Fired Make-Up Air Units
  • Unit Heaters
  • Strainers
  • Air Vents
  • Liquid Drainers
  • Heat Transfer Packages
  • Digital Water Mixing Valves
  • Air Cooled Condensers/Dry Coolers
  • Steam Filters
RETURN
  • Electric Condensate Pumps
  • Steam/Air-Powered Condensate Pumps
  • Packaged Condensate Pump Skids