Mechanical Steam Traps | Advantages & Disadvantages

Mechanical steam traps consider the distinction in density between steam and condensate so as to work. They will continuously pass massive volumes of condensate and are suitable for a large range of process applications. Varieties include ball float and inverted bucket steam traps.

Mechanical Steam Traps

Ball float steam trap (Mechanical steam traps)

The ball float kind trap operates by sensing the distinction in density between steam and condensate. Within the case of the trap shown within the image on the proper (Float trap with air cock), condensate reaching the trap can cause the ball float to rise, lifting the valve off its seat and cathartic atmospheric phenomenon.

ball float steam trap

As is seen, the Valve is usually flooded and neither steam nor air can go through it, thus early traps of this type were ventilated employing a manually operated cock at the highest of the body.

Trendy traps use a regulator air vent, as shown within the image on the proper (Float trap with regulator air vent). This permits the initial air to pass while the trap is additionally handling condensate.

The automatic air vent uses a similar balanced pressure capsule component as a regulator steam trap and is found within the steam area higher than the condensate level.

When releasing the initial air, it remains closed till air or alternative non-condensable gases accumulate throughout traditional running and cause it to open by reducing the temperature of the air/steam mixture.

The regulator air vent offers the additional benefit of considerably increasing condensate capability on cold start-up.

In the past, the regulator air vent was some extent of weakness if water hammer was present within the system. Even the ball might be broken if the water hammer was severe. However, in trendy float traps the air vent could be a compact, very strong, all stainless-steel capsules, and also the trendy welding techniques used on the ball make the entire float-thermostatic steam trap terribly strong and reliable in water hammer situations.

In some ways, the float-thermostatic trap is that the closest to a perfect steam trap. It’ll discharge condensate as shortly because it is created, regardless of changes in steam pressure.

Advantages of the float-thermostatic steam trap.

The trap continuously discharges condensate at steam temperature. This makes it the primary selection for applications wherever the rate of warmth Transfer is high for the area of a heating surface offered.

it’s able to handle significant or light-weight condensate loads equally well and isn’t suffering from wide and unexpected fluctuations of pressure or flow rate.

As long as an automatic air vent is fitted, the trap is ready to discharge air freely.

it’s an oversized capability for its size.

The versions that have a steam lock release Valve are the sole kind of trap entirely appropriate for use wherever steam lockup will occur is resistant to water hammer.

Disadvantages of the float-thermostatic steam trap

although less susceptible than the inverted bucket trap, the float kind trap is broken by severe phase change and also the body ought to be lagged, and/or complemented with a little supplementary regulator drain trap if it’s to be fitted in an exposed position.

Like all mechanical kind traps, totally different internals is needed to permit operation over variable pressure ranges. Traps designed to work on higher differential pressures have smaller orifices to balance the buoyancy of the float. If a trap is subjected to a higher differential pressure than supposed, it’ll shut and not pass condensate.

Inverted bucket steam trap (Mechanical steam traps)

The inverted bucket steam trap is shown in Figure. As its name implies, the mechanism consists of an inverted bucket that is connected by a lever to a Valve. A necessary part of the trap is that the little air vent hole within the top of the bucket.

(i) The bucket hangs down, pull the valve off its seat. Condensate flows below the bottom of the bucket filling the body and flowing away through the outlet.

(ii) The arrival of steam causes the bucket to become buoyant, it then rises and shuts the outlet.

(iii) The trap remains shut till the steam within the bucket has condensed or bubbled through the vent hole to the top of the trap body. It’ll then sink, pull the most Valves off its seat. Accumulated condensate is discharged and also the cycle is continual.

 In (ii) Air reaching the trap at start-up will provide the bucket buoyancy and shut the Valve. The bucket vent hole is important to permit air to escape into the top of the trap for ultimate discharge through the most Valve seat. The hole, and also the pressure differential, is little that the trap is relatively slow at discharge air. At a similar time, it should pass (and therefore waste) a particular quantity of steam for the trap to work once the air has cleared. A parallel air vent fitted outside the trap can cut back start-up times.

Operation of an inverted bucket steam trap