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Steam traps are used to trap steam & allow discharge of condensates and non-condensable gases with a negligible consumption or loss of live steam from steam piping, steam tracers, and in steam-consuming equipment

Steam traps are mainly classified into three main categories based on operating principles, construction-

Mechanical Steam Traps

Steam used for secondary heating like Coils, vessels, heat exchangers etc. generate condensate post heat transfer. This condensate can handle by Mechanical traps&remove condensate through the use of the mechanical properties of steam v/s condensate. Since liquid is heavier than steam, it will travel to the bottom of the system. Mechanical traps will have a bucket or float that rises and falls with respect to level of the condensate which usually has a mechanical linkage that opens and closes the valve. Mechanical traps operate in direct relationship to condensate levels present in the body of the steam trap. Inverted bucket and float traps are examples of mechanical traps. Float traps can have a mechanical linkage or can seal the trap through use of the float itself. Float trap operates on buoyancy principal

UKL Inverted Bucket Trap- works on the principle of Buoyancy, [densities difference of Water and Steam].The rising in condensate level fills and envelopes the Bucket causing it to sink which open the mechanically linked valve and discharges the condensate and reverse happens when the level of condensate drops Steam enters the bucket, causes the floating of the Bucket which close the valve and stops condensate discharge & traps the steam.

Features:-

• UKL UIBT-28US is optimally sized for complete removal of condensate.
• UKL UIBT-28US is suitable with universal connector.
• UKL UIBT-28US is designed to eliminate internals damages caused by impingement of condensate.
• Maintenance free and long life.

UKL Ball Float Trap - operates by sensing difference in density between steam and condensate, discharge condensate near to steam saturation temperature, which works on the principle of Buoyancy, The rising condensate level elevates the Float open the valve and discharges the condensate. When the level of condensate drops, the float falls down and the valve close the trap.

It is commonly used for most of process heating applications. Wherever steam is used for indirect heating application, the trap to be used must be of mechanical design. It is a continuous discharge type steam trap. This trap can handle very high condensate loads and the discharge will be proportional to the differential pressure across the trap.

There may be other similar process applications where the heat load is small and these trap can handle small and fluctuating loads as well.

These trapsare provided with two optional features, called Steam Lock release (SLR) &Thermostatic Vent (TV). The SLR is a manual operation to release steam that may hamper free movement of the float on water level. The TV will ensure that air and such un dissolved gases will be automatically vented out when present in condensate.

Thermostatic Steam Traps

Thermostatic Stream Traps removes condensate through the temperature difference of steam &liquid phase. The trap is driven through expansion and contraction of an element that is exposed to the heat from steam or condensate. These traps take a temperature drop below the saturation curve to open and remove condensate. These traps can perform with the help of filled element or bellows or bimetallic element.

UKL Balance pressure trap	UKL Bi-metallic trap	UKL Clean room trap

Thermodynamic traps

Thermodynamic traps operates on the dynamic principals of steam & condensate (Velocity difference) and use of Bernoulli’s principle.

Condensate pressure is used to open the trap by lifting the disc, discharging condensate in low pressure. Due to low pressure flashing of condensate takes place.

High flash steam velocity (approximately 5 times of condensate) creates a low pressure zone below the disc. Accumulated flash steam force over the disc becomes greater than the incoming condensate pressure this leads to closure of the disc. Subsequently the flash steam condenses and the incoming higher pressure condensate pushes the disc opening the trap and thus the cycle continues.

UTD 55	UTD 62	UTD 120

Type wise applications of Steam Traps-

Ball float steam traps are preferred for removal of condensate from steam Equipments, steam distribution lines for continuousremoval of condensate at steam temperature when it enters the trap body & thus avoid condensate accumulation and reduces risk of water hammer in the steam line. These traps can handle heavy or light condensate loads equally well and not affected by wide and sudden fluctuations of pressure or flow rate.

Applications Suited to the Inverted Bucket traps-

During start-up, air is vented through a weep hole in the top of the bucket into the return line. When steam or Air inserted to the trap, it enters the underside of the bucket and collects in the top of the bucket. The contained air and steam cause the bucket to become buoyant and rise in the condensate causing the lever mechanism to close the discharge valve into its seat.

The bucket loses its buoyancy as the enclosed steam condenses due to radiation losses and steam escaping through the bucket vent hole. Due to this, the weight of the bucket will cause it to fall and pull the valve off its seat, and the cycle repeats.

Inverted bucket trap responds slower than the ball Float trap, which operates immediately due to its self-contained buoyancy over water.

Applications Suited to Thermodynamic traps -

Thermodynamic trap is an extremely robust steam trap with a simple design & operation. The trap working on dynamic effect of flash steam as it passes through the trap, The disc is only moving part above the seat & inside the cap.

On start-up, incoming pressure raises the disc, and cool condensate plus air is immediately discharged from the chamber, under the disc, and out through outlets

Hot condensate inserted to the inlet passage into the chamber under the disc drops in pressure and releases flash steam moving at high velocity. This high velocity creates a low pressure area under the disc,

At the same time, the flash steam pressure builds up inside the chamber above the disc, & weight of disc forcing it down against the incoming condensate until it down on seats, the flash steam is trapped in the upper chamber, and the pressure above the disc equals the pressure being applied to the underside of the disc. However, the top of the disc is subject to a greater force than the underside, as it has a greater surface area.

Eventually the trapped pressure in the upper chamber falls as the flash steam condenses. The disc is raised by the now higher condensate pressure and the cycle repeat,

They are compact, simple, lightweight and have a large condensate capacity for their size.

It can be used on high pressure and superheated steam and are not affected by water hammer or vibration.

As the disc is the only moving part, maintenance can easily be carried out without removing the trap from the line

Applications Suited to the Thermostatic/ balance pressure Trap

Operating temperature of Thermostatic trap is affected by the surrounding steam pressure. The operating element is a capsule containing a special hydrocarbon with a boiling point below that of water. In the cold conditions that exist at start-up, the capsule is contracts. The valve is off its seat and is wide open, allowing unrestricted removal of air. This is a feature of all balanced pressure traps and explains why they are well suited to air venting. As condensate passes through the balanced pressure steam trap, heat is transferred to the liquid in the capsule. The liquid vaporizes before steam reaches the trap. The vapour pressure within the capsule causes it to expand and the valve shuts. Heat loss from the trap then cools the water surrounding the capsule, the vapour condenses and the capsule contracts, opening the valve and releasing condensate until steam approaches again and the cycle repeats 

Construction is Small, light and has a large capacity for its size.

The valve is fully open on start-up, allowing air and other non-condensable gases to be discharged freely and giving maximum condensate removal when the load is maximum.

 Trap maintenance is simple. The capsule and valve seat can be easily removed and replacement can be fitted in a few minutes without removing the trap from the line.

Selection of right trap for your application

By the help of this blog, you can select a proper steam traps for various applications. For more information about selection ofprecise traps for your applications, contact to UKL steam specialist.