Steam Theory 1. Basics of Steam What is Steam? Principal Applications for Steam Types of Steam Flash Steam How to Read a Steam Table 2. Steam Heating Heating with Steam Steam Heating Mechanism Overall Heat Transfer Coefficient What is Vacuum Steam? Tracing the Causes of Heat Maintenance Issues 3. Basics of Steam Traps What is a Steam Trap? The History of Steam Traps #1 The History of Steam Traps #2 How Mechanical Traps Work: A Look at their Mechanism and Merits How Disc Traps Work: A Look at their Mechanism and Merits How Bimetal-Type Thermostatic Steam Traps Work: A Look at their Mechanisms and Merits 4. Steam Trap Selection Steam Trap Selection: How Application Affects Selection Steam Trap Selection: Understanding Specifications Steam Trap Selection: Safety Factor and Life Cycle Cost Traps and Orifices Part 1 Traps and Orifices Part 2 Casting vs. Forging Applications of Different Types of Steam Traps Don't Get Steamed : Selecting Steam Trap Design Understanding Steam Traps Compare Two Fixed Orifice Venturi Products to a Variable Orifice Free Float Steam Trap 5. Steam Trap Problems Is My Trap Leaking Live Steam? Temperature Control Trap Precautions Trap Installation Orientation Trap Back Pressure Double Trapping Group Trapping Steam Locking Air Binding My Steam Trap Is Good - Why Doesn't It Work? 6. Steam Trap Management Introduction to Steam Trap Management Steam Trap Losses - what it costs you A Guide to Steam Trap Testing Implement a Sustainable Steam Trap Management Program Impact Plant Performance by Improving the Steam System 7. Water Hammer Water Hammer: What is it? Water Hammer: The Mechanism Water Hammer: Cause and Location Water Hammer: In Steam Distribution Lines Water Hammer: In Equipment Water Hammer: In Condensate Transport Piping Identifying Water Hammer Using a Thermal Camera Mitigation of Water Hammer in Vertical Flashing Condensate Transport Piping Stop Knocking Your Condensate Return Steam Trap Management: Do Something; Anything. Please! 8. Risk Mitigation Steam System Optimization and Risk Mitigation Risk Based Methodology for Industrial Steam Systems Why Bad Things Happen to Good Steam Equipment Beware of the Dangers of Cold Traps Steam System Winterization: How to Protect Your Plant 9. Steam Quality Wet Steam vs. Dry Steam: The Importance of the Steam Dryness Fraction Separators and their Role in the Steam System Clean & Pure Steam Temperature Problems Caused by Air Removing Air from Steam Equipment Air Vents for Steam Steam Quality Considerations 10. Steam Distribution Best Practices for Condensate Removal on Steam Lines Installation Tips for Steam Traps on Steam Mains Erosion in Steam and Condensate Piping Corrosion in Steam and Condensate Piping Allocate New Plant Focus to Steam System Design—Part 1 11. Condensate Recovery Introduction to Condensate Recovery Returning Condensate and When to Use Condensate Pumps Condensate Recovery: Vented vs. Pressurized Systems Condensate Recovery Piping What is Stall? Methods of Preventing Stall Cavitation in Condensate Pumps Steam Heat Exchangers are Underworked and Over-Surfaced Allocate New Plant Focus to Steam System Design—Part 2 Optimize Reboiler Performance via Effective Condensate Drainage Vent Away Condensate Pump Frustrations in a Flash 12. Energy Efficiency Tips to improve steam plant efficiency Advice on Winter Preparation for Steam Systems Insulating Traps Steam Compressors Why Save Energy? Management Strategies for Conserving Energy Recovering Steam Clouds and Waste Heat Waste Heat Recovery Boiler Energy Saving Tips Steam Line Energy Saving Tips Steam-Using Equipment Energy Saving Tips Preventing Steam Leaks Handle Steam More Intelligently Optimize the Entire Steam System Use Available Data to Lower System Cost 13. Compressed Air / Gas Removing Condensate from Compressed Air Preventing Clogging of Air Traps Air Compressor Energy Saving Tips Improving Compressed Air Quality and Countermeasures Against Leaks 14. Other Valves Types of Manual Valves Bypass Valves Check Valve Installation and Benefits Pressure Reducing Valves for Steam How Mechanical Traps Work: A Look at their Mechanism and Merits Contents: Mechanical traps are steam traps that operate on the principle of specific gravity (specifically the difference in the specific gravities of water and steam), unlike other types of steam traps that rely on temperature change or velocity/phase change. In mechanical traps, the valve opens and closes due to the movement of a float that rises and sinks with the flow of condensate. Mechanical traps are able to operate in precise response to the flow of condensate without their performance being compromised by most external factors. This is one of their distinct advantages over thermostatic and thermodynamic steam traps, whose performances can be affected by external factors such as rain, wind, or even insulation. Two Designs: Float and Inverted Bucket There are two main types of mechanical steam traps: float traps and inverted bucket traps. Float traps typically utilize a sealed spherical float, while inverted bucket traps utilize a buoyant, cylindrical cup turned upside-down. Buoyancy is the key force operating at the core of both types of mechanical traps, but their structures and principles of operation are quite different. Float Type In float traps, the position of the float is affected directly by the level of condensate in the trap. The float responds to condensate flow, opening and closing the valve to compensate accordingly. There are two basic designs used for float traps: lever float and Free Float®. In lever float designs, a float is attached to a lever that controls the valve. As condensate enters the trap, the float becomes buoyant and moves the lever, causing the trap valve to open. However, due to the limited movement of the lever arm, the valve head often remains in the path of condensate flow, which may result in an extra pulling force acting to close the valve during high flow conditions. In TLV Free Float® traps, the float is not attached to a lever, and the float itself serves as the valve for the trap. A Free Float® is able to independently rise away from the orifice, allowing condensate to be drained free of obstruction. Additionally, the natural rotation of the Free Float® allows for an almost infinite number of contact points to seal the orifice, significantly reducing localized valve wear. TLV Free Float® Steam Trap Inverted Bucket Type In inverted bucket steam traps, the bucket within the trap is attached to a lever that opens and closes the trap valve in response to the bucket’s motion. When steam or air flows into the underside of the inverted bucket and condensate surrounds it on the outside, the steam causes the bucket to become buoyant and rise. In this position, the bucket will cause the trap valve to close. There is a vent hole in the top of the bucket that allows a small amount of the vapor to be released into the top of the trap, where it is discharged downstream. As vapor escapes through the vent hole, condensate starts to fill the inside of the bucket, causing it to sink and allowing the lever to open the trap valve and discharge condensate (along with any vapor held in the trap). Inverted Bucket Steam Trap Continuous Drainage: A Significant Advantage of Float Type Traps One key difference in the operation of float traps and inverted bucket traps is the type of condensate drainage they provide; float traps provide continuous drainage, whereas inverted bucket traps provide intermittent drainage. Float Traps Offer Continuous Drainage In steam traps that continuously drain condensate, the float rises and falls based on the condensate load entering the trap, allowing the valve to automatically adjust to the level of condensate in the trap. When condensate enters, the valve opens just enough to drain the condensate, closing once the flow of condensate ceases. This allows the trap to respond quickly to fluctuations in condensate load. Inverted Bucket Traps Offer Intermittent Drainage On the other hand, in steam traps that drain intermittently, condensate is not drained until a significant amount of vapor is vented from the bucket, thereby triggering the bucket to sink and the valve to open. Consequently, when the valve is closed, it can shut completely, with no condensate drained until a certain amount of steam is vented from the inside of the bucket. The flow of condensate from equipment and steam lines is generally continuous, regardless of how a particular steam trap operates. As such, in steam traps that drain intermittently, condensate will accumulate within the trap for as long as the valve remains closed. Trap Selection Affects Operation in Low-Condensate Systems Steam traps are a necessity in any system where condensate forms, even if it forms in very small volumes, such as in systems using superheated steam. Because of this, it is important to understand how steam traps operate in environments where condensate loads may be extremely low. In superheated systems, there is often little condensate. During such operations, there may not be sufficient water inside an inverted bucket trap to create buoyancy. As a result, the bucket falls to the bottom of the trap, leaking large amounts of superheated steam. This is not only costly, but can also elevate return backpressure. Float traps are also affected during use in superheated systems. In lever float traps, the valve head is very close to the seat. Low flow operation may cause condensate to flow through the valve at extremely high velocities, causing erosion of valve components known as “wire draw.” A Free Float®, however, pivots off the top of the seat during low flow service. Since the valve head is not directly in the flow path, wire draw is prevented even under low flow conditions. Float Traps in Low-Condensate Systems Inverted Bucket Traps in Low-Condensate Systems Orifice Number Indicates Maximum Operable Pressure One notable characteristic of mechanical traps is that there are different orifice sizes based on pressure differential available for each model. The orifice size is designed to match the maximum operating pressure (PMO) of the trap. It is important to understand that if a trap is used above its PMO, the trap valve may not be able to open. In this situation, known as “pressure block,” the trap remains closed, and condensate will not be drained. To learn more about mechanical traps and orifice numbers, please read: Traps and Orifices Part 1 Traps and Orifices Part 2 The History of Steam Traps #2 How Disc Traps Work: A Look at their Mechanism and Merits Also on TLV.com Services How Disc Traps Work: A Look at their Mechanism and Merits The History of Steam Traps #1 Mechanical Steam Traps