Analysis And Application Of The Composition Principle Of Various Types Of Traps

- Aug 07, 2020-

The trap is called a trap, also called an automatic drain or a condensate drain. It is divided into steam system use and gas system use. The steam trap is installed at the end of the pipeline heated by steam, and its role is to continuously discharge the condensate in the steam heated pipeline to the outside of the pipeline. Most steam traps can automatically identify steam and water (not including thermostatic type), so as to achieve the purpose of automatic steam blocking and drainage. Drainers are widely used in petrochemical, food and pharmaceutical, power plant and other industries, and play a great role in energy saving and emission reduction. There are also many types of traps. Before choosing traps, we need to understand the principles of various traps.

1 Float trap:

Float traps are mainly composed of valves, shafts, guide pipes, floats and shells. When the condensed water in the equipment or pipeline enters the trap under the pressure of steam and gradually increases to close to the full buoy, the weight of the buoy exceeds the buoyancy and sinks downward, causing the throttle valve to open. In this way, the condensed water in the cylinder is discharged through the pipe and valve under the action of steam pressure. When the condensate in the pontoon is nearly exhausted, the weight of the pontoon is reduced and it floats upwards, closing the throttle valve, and the condensate starts to accumulate in the pontoon. Working periodically in this way can automatically drain the condensed water and prevent the escape of steam.

2 Bell-shaped float trap:

Bell-shaped float traps, also known as bucket traps, are mainly composed of regulating valves, buckets, shells and filter devices. The bucket inside the trap is turned upside down, initially in the lowered position, and the regulating valve is open. When the cold air and condensed water in the equipment or pipeline enter the trap under the pressure of steam, it will be discharged by the regulating valve. On the one hand, when steam and a small amount of air that has not been discharged gradually fill the internal volume of the bucket, and at the same time condensate continues to accumulate, the bucket rises due to buoyancy, which closes the regulating valve and stops discharging the condensed water. On the other hand, a small part of the steam and air inside the bucket is discharged from the small hole on the top of the bucket, and most of it is condensed into liquid after the heat is dissipated, so that the buoyancy of the bucket gradually decreases and falls, so that the regulating valve is opened and the condensed water is discharged again. Such periodic work can not only automatically drain the condensate, but also prevent the escape of steam.

3 Thermodynamic traps:

When the condensed water in the equipment or pipeline flows into the choke drain valve, the steam in the pressure transformation chamber will condense and reduce the pressure. The force under the valve is greater than the force above, so the valve is lifted. Because the condensed water has a higher viscosity and a lower flow rate than steam, it is not easy to cause negative pressure between the valve plate and the valve bottom. At the same time, the condensed water cannot easily flow into the variable pressure chamber through the gap between the valve plate and the shell, so that the valve plate remains open and condenses. The water flows through the annular groove and is discharged. When the steam in the equipment or pipeline flows into the trap, because the steam has a lower viscosity and a higher flow rate than condensed water, it is easy to cause negative pressure between the valve plate and the valve seat, and part of the steam flows into the variable pressure chamber, so the valve plate is above The force is greater than the force below, so that the valve plate closes quickly. By working periodically in this way, the condensed water can be discharged automatically and the escape of steam can be prevented.

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