Steam Traps are essential devices that remove condensate and non-condensable gases from steam systems while preventing steam loss. Choosing the right trap improves efficiency, safety, and energy savings. For engineers and plant operators, understanding what are steam traps and the different types of steam traps is key to reliable performance.OUVI Steam Traps are trusted worldwide for their advanced design and durability. As a technology enterprise, OUVI integrates design, production, and service, providing energy-saving steam traps, filters, and steam-water separators. With solutions covering low to ultra-high pressure applications, OUVI ensures stable operation and efficient drainage across different industries. In this guide, we’ll explore 19 different types of steam traps, their working principles, and applications to help you choose the right solution.
Steam traps are automatic valves that discharge condensate and air from steam systems while preventing live steam from escaping. They play a crucial role in improving thermal efficiency, reducing energy losses, and protecting equipment from water hammer and corrosion. A steam trap valve operates by detecting differences in temperature, pressure, or density between steam and condensate. Understanding the steam trap working principle helps engineers select the best option for their system.
Generally, steam traps are divided into three main categories:
Mechanical Steam Traps
Thermostatic Steam Traps
However, within these families, there are many different steam traps with unique designs. Including pressure-based classifications and special-purpose traps, we can identify at least 19 types of steam traps and their application.
A float steam trap uses a ball float that rises with condensate levels, opening a discharge valve for continuous drainage. Ideal for heat exchangers and process equipment with steady loads.
Advantages: Continuous operation, reliable under variable conditions.
Limitations: Sensitive to dirt and freezing.
The inverted bucket steam trap works with an upside-down bucket that floats on steam and sinks in condensate. It opens and closes intermittently.
Best use: Medium/high-pressure steam lines and process plants.
Pros: Rugged, durable, resists water hammer.
Cons: Can lose prime if not properly maintained.
This variation of the float trap uses a lever mechanism to improve valve action, allowing precise condensate removal.
Application: Systems with fluctuating loads.
With two discharge ports, this trap handles large condensate volumes efficiently.
Best use: Heavy-duty industrial heating and large-scale process systems.
The bimetallic steam trap uses two strips of metal with different expansion rates. As they bend with heat, the valve opens or closes.
Use: High pressure and superheated steam.
Benefit: Strong, resistant to corrosion.
A capsule filled with volatile fluid expands or contracts based on temperature, making it a popular choice as air traps for venting.
The bellows trap uses a fluid-filled metal bellows that expands with steam temperature.
Application: Medium-pressure equipment, compact designs.
This trap contains a liquid element that expands when heated, closing the valve.
Use case: Low-pressure tracing and small heating devices.
The most common thermodynamic steam trap, it operates by pressure differences of flash steam acting on a disc.
Application: Pipelines, refineries, outdoor systems.
Pros: Compact, robust, handles high pressures.
A disc trap combined with a strainer, offering protection from dirt and debris.
Best for: Steam lines with contamination.
This design allows faster cycling, making it ideal for distribution headers and systems requiring rapid discharge.
These traps vent air and non-condensable gases during startup, ensuring rapid heating.
A fixed orifice drains condensate continuously, best for stable load conditions.
Pros: No moving parts, long life.
Cons: Not self-adjusting, wastes steam under fluctuating loads.
Works by using flow momentum (impulse) to move the valve.
Use: High-pressure pipelines and refineries.
A hybrid design that combines mechanical and thermodynamic principles for high-efficiency steam systems.
Used in HVAC, tracing lines, food processing.
Common in general industry and manufacturing.
Applied in power generation, refineries, petrochemicals.
Advanced designs for critical systems demanding extreme reliability.
| Type of Steam Trap | Working Principle | Best Applications | Advantages | Limitations |
|---|---|---|---|---|
| Float Steam Trap | Buoyancy of float | Process plants, exchangers | Continuous drainage | Sensitive to dirt/freezing |
| Inverted Bucket Trap | Bucket rises/sinks | Medium/high pressure lines | Rugged, durable | Intermittent discharge |
| Lever Type Trap | Float + lever | Fluctuating loads | Precise control | Complex design |
| Double Orifice Float Trap | Two ports for discharge | Heavy condensate load | High capacity | Costlier, bulky |
| Bimetallic Trap | Metal strip expansion | High pressure, superheated steam | Strong, durable | Slow response |
| Balanced Pressure Trap | Capsule with volatile fluid | Air venting, tracing | Fast startup | Limited heavy load use |
| Bellows Trap | Fluid-filled bellows | Medium pressure | Compact, sensitive | Fatigue over time |
| Liquid Expansion Trap | Liquid expansion | Low-pressure tracing | Simple, cheap | Not for high pressure |
| Thermodynamic Steam Trap | Flash steam pressure | Pipelines, refineries | Compact, high pressure use | Noise, dirt sensitive |
| Disc with Strainer | Disc + strainer | Dirty steam systems | Protects from debris | Slightly higher cost |
| Quick-Opening Disc | Fast cycle | Headers, distribution | Rapid response | Limited load handling |
| Air Traps | Temp sensing | Startup venting | Prevents air lock | Not for heavy load |
| Orifice Trap | Fixed hole | Stable loads | Durable, simple | Wastes steam if fluctuating |
| Impulse Trap | Flow momentum | High-pressure pipelines | Handles extreme pressure | Niche use |
| Thermo-Compression Trap | Hybrid | Specialized systems | Energy-efficient | High cost |
| Low-Pressure Traps | Pressure-based | HVAC, food | Efficient at low load | Not for high duty |
| Medium-Pressure Traps | Pressure-based | Industry | Balanced use | Limited to mid-range |
| High-Pressure Traps | Pressure-based | Power/refineries | Reliable, strong | Higher maintenance |
| Ultra-High Pressure Traps | Advanced designs | Critical systems | Extreme reliability | Expensive |
While there are many different steam traps, not all brands deliver the same reliability. OUVI is a technology enterprise specializing in filters, energy-saving steam traps, steam-water separators, and pipeline supporting equipment.OUVI provides complete steam system solutions—from front-end temperature control and pressure regulation, mid-end steam resistance and drainage, to end recycling. Their products cover low pressure, medium pressure, high pressure, and ultra-high pressure systems. With testing certified by the National Valve Product Inspection and Testing Center, OUVI Steam Traps consistently exceed national standards and hold over 30 patents. For engineers seeking efficiency, durability, and innovation, OUVI Steam Traps are trusted worldwide.
From mechanical float steam traps to thermodynamic steam traps and specialized air traps, understanding the different types of steam traps and their applications ensures that steam systems run at maximum efficiency. Whether you are asking what are steam traps, how many types of steam traps exist, or what are the different steam traps suitable for your plant, this guide provides the answers. If you’re looking for high-performance solutions backed by advanced technology, OUVI Steam Traps offer unmatched reliability. Contact OUVI today to explore the right steam trap for your system and take a step toward greater energy savings and operational efficiency.
