Steam trapping


Steam trap

Thermal, thermodynamic and float condensate traps in cast iron, modular cast iron or stainless steel. Consult our "steam specialist" to make the right choice.

A steam trap is an accessory used to remove condensate and non-condensable gases and allow the usable steam to pass through without much pressure loss. The trap generally opens, closes or regulates the flow automatically.

Three properties of a steam trap are:

  • Drain the condensate (to prevent water hammer in the steam system)
  • The operation of the trap must consume/lose as little usable steam as possible in order to preserve as much energy as possible.
  • It must be capable of evacuating air and other non-condensable gases.

Mechanical and thermostatic traps open when condensate and inert gases have to be removed and close when all condensate has been removed. The process repeats itself when new steam is again condensed and ready to be drained.

The steam trap must be specified for the amount of condensation expected from the installation for proper operation. A too small trap can cause problems because not all the condensate can be drained and it can become a blockage for the live steam. However, a too large trap will wear out sooner and therefore consume more energy.

Types of steam traps:

The steam traps can be divided into four main types:

Mechanical steam traps

These traps have a float (or reverse bucket) that rises and falls with the condensate level in the valve and usually has a mechanical coupling that opens and closes the valve. Mechanical traps work in direct relation to the condensate level in the body of the trap. Mechanical traps have a typical service life of 3-4 years.
Some examples of mechanical steam traps are:

  • Float trap
  • Clock float trap
  • Reverse bucket steam trap

Thermostatic steam trap

This trap (also known as a bi-metal trap) has a valve whose seat is driven by the difference in temperature between the liquid condensate and steam. The working mechanism is a number of stacked bimetal discs. Due to the expansion or shrinkage of the different materials at the temperature, deformation occurs. This deformation is converted by the steam trap into the opening or closing of the valve.

Thermodynamic steam traps

This trap acts on the difference in dynamic response to speed changes in the flow of compressible and incompressible fluids. When steam enters, the disc (valve) is pressed against the valve seat by static pressure above the disc. The static pressure over a large area overcomes the high inlet pressure of the steam. As the steam begins to condense, the pressure against the disc decreases and the load on the condenser is reduced. This makes a thermodynamic trap essentially a "time cycle" device: it will open, even if only steam is present, this can cause premature wear. If non-condensable gas is trapped on top of the disc, it can cause the siphon to be closed.

Venturi steam trap

This simplest form of the trap is a small hole (orifice) installed at the lowest point of the installation (venturi trap). Since the condensate collects at the lowest point and the amount of living steam is about 1200 times greater (water in gaseous form) than this hot liquid, the condensate is effectively removed and the steam is blocked. However, the vast majority of steam traps in current operation have a mechanically or thermostatically controlled construction. At start-up, this trap will very effectively remove air and non-condensable gases. As soon as condensate forms, the live steam losses will decrease.

Buying steam traps

The steam traps shown on our website are from Spirax Sarco because we are a partner of Spirax Sarco. We chose this party because it is a high quality brand and there is a wealth of knowledge in the organization. The specialists of Ebora can fall back on this in the more difficult cases and possibly visit you together with Spirax Sarco.

The purchase price of the chosen trap is often considerably lower than the additional costs of the wrong choice for the application or the wrong way of installation in the installation. Especially in the case of steam (the energy), the non-optimal application of the fittings has a direct influence on the energy consumption.

We also recommend that you regularly check (or have checked) the operation of the steam traps, as wear and tear can lead to a direct profit leakage.

In addition to Spirax Sarco, Ebora also supplies other brands of steam traps on request.