What is Steam trap ? 

 steam trap definition

What is steam trap definition ? steam trap  is used to do this with negligible consumption or loss of live steam  Each steam application has its own steam trap requirements.  Selecting the right steam trap for your application could have a significant positive impact on your process.
For example: condensate must be removed promptly from a plant where maximum heat transfer is sought at all times.

steam trap overview

 Maybe the first question is that why steam trap is used ? to answer this question and know why steam trap is used we must know the steam trap function so  steam traps are automatic valves  used in every steam systems to remove condensate,air and other non-condensable gases while preventing and minimizing the passing of steam.if condensate is allowed to collect, it reduces the flow capacity of steam lines and thermal capacity of heat transfer equipment. in addition excess condensate can lead to "water harmmer" with potentially destructive and dangerous results. air that remains after system  startup reduces steam pressure and temperature and may reduces the thermal capacity of heat transfer equipment.non-condensable gases like oxygen and carbone dioxide cause corrosion.finally steam that passes through the trap provides no heating service.this effectivley reduces the heating capacity of steam system or increases the amount of steam that must be generated to meet the heating demand. 

 How do steam traps work?

How does steam trap work ? to know how do steam traps work, first we must  know that the steam trap function is not an easy task and condensate prresure and flow rate vary significantly at various points in a steam distribution system.also in steam trap operation ,as a result many different types of steam traps have been developed.steam traps are commonly classified by the physical process causing them to open and close. 

 Types of steam trap 

According to the steam trap function and how do steam trap works,we will have different types of steam trap.the three major categories of steam traps are ;

A) Mechanical 

B)Thermostatic

C)Thermodynamic

A) Mechanical Steam Trap

Mechanical steam trap working principle is based on different in density but How do the mechanical steam traps work ? Steam trap operation in a mechanical type is driven by different in density between condensate and steam.the denser condensate rests on the bottom of any vessel containing the two fluids. as the additional condensate is generated, it's level in the vessel will rise . this action is transmitted to a valve via either "free float" or a float and connecting levers in a mechanical steam trap. on type  of mechanical steam trap is inverted buket trap that we can see here the steam trap symbol of inverted buket trap. 

 

  

 Steam entering the submerged buket causes it to rise upward and seal the  valve against the valve seat.  as thesteam condenses inside the buket or if condensate is predominately entering the buket will cause it to sink and pull the valve away from the valve seat.any air or other condensable gases entering the buket will cause it to floatand the valve to close Thus the top of the buket has a small hole to allow non-condensable gases to escape. the hole must be relatively small to avoid excessive steam loss.

B)Thermostatic Steam Trap

steam trap operation in thermostatic type is based on the  difference in the temperature between steam and sub-cooled consendate.valve actuation is achieved via expansion and contraction of bimetallic element or a liquid filled  bellows. bimetallic and bellows Thermosstatic Traps are shown in these pictures

   

Although both types of thermo static  steam traps closed when they exposure to steam expand the bimetallic elements or bellows there are  important difference in thermo static  steam traps and thermo static  steam  works to open the valves in bimetallic steam trap while expansion of sttraps bimetallic elements works in opposite direction changes in the downstream pressure will affect temperature at which the valve opens or closes.

C) Thermodynamic Steam trap 

Thermodynamic steam trap are driven by difference in pressure applied by steam and condensate with the presence of steam or condensate within the trap being affected by the design of the trap  and it's impact on the local flow velocity and pressure.

according to the thermodynamic steam trap function ,there are three types of thermodynamic steam traps. however the design of are these steam traps are different but these thermodynamic steam traps have the  similar operating principle the three types of thermodynamic steam traps are Disc, piston and lever. you can see these steam trap symbols here : 

  

We suggest you to read KARAJET steam trap  Catalog, if you want to know more about steam trap: 

Karajet steam trap Catalog