Hydrostatic drain valve-4

Release time:

2024-04-04

Temperature controlled drain valve

Thermostatic drain valve is also called adjustable thermostatic drain valve. It controls the temperature of the discharged condensate, not the temperature of the condensate accumulated in the pipeline. The temperature sensing element in the valve is composed of a stack of bimetal plates, and the side with lower expansion coefficient in each pair of bimetal plates is opposite to each other. One end of the disc is against the shoulder of the valve rod, and each pair of discs is pressed against each other by a small compression spring. The spring acting under the shaft seal opens the valve seat hole beside the initial valve.

When the unit is started, the steam trap is in the open state, and the air is discharged from the valve nozzle before the steam enters the steam trap; then the low-temperature condensate water flows into the steam trap and is discharged through the valve nozzle; when the condensate temperature starts to rise, the bimetal sheet begins to bend, and the side with the lower expansion coefficient of each pair of bimetal sheets contacts with each other, and a downward pressure is generated on the shaft shoulder; and the pressure passes through the shaft The shoulder is passed to the stem and head to move the head toward the seat while limiting the flow of condensate.

If the steam unit and flow are reduced and the condensate becomes hotter, the bimetal disc will expand more and the reading head will be pushed onto the valve seat. The valve remains fully closed at a preset temperature. The condensate accumulates until it cools down enough to allow the bimetallic sheet to retract and the valve reopens.

When the valve is closed, if the condensate temperature is too high, the bimetal disc will expand excessively. When the reading head has fallen on the valve seat, the force generated by the excessive expansion of bimetal sheet will be absorbed by the overpressure protection spring. Even if the valve head is closed tightly and cannot move, the compression spring can provide space for bimetal expansion.

The thermostatic drain valve is used to discharge condensate at a fixed temperature (set temperature). The temperature can be adjusted by adjusting the screw. In fact, the adjusting screw is used to make the valve head close to or away from the valve seat. When adjusting the set temperature, it must be noted that the set temperature cannot be too close to the temperature of saturated steam. Otherwise, when the steam pressure drops below the set temperature, a large amount of steam will be ejected from the drain valve.

The temperature control steam trap uses the chemical substances in the temperature sensing element to expand and shrink the temperature and change the state, so that the valve can be opened and closed, so as to achieve the purpose of steam blocking and drainage. The discharge temperature of condensate can be adjusted in a certain range. The valve overcomes the shortcoming of bellows easy to break, has a long service life and a leakage rate of less than 0.1%.

Due to the structural characteristics of the temperature control drain valve, when the condensate temperature is higher than the set temperature, it will accumulate in the pipeline, which can be obviously used, which makes the valve suitable for steam pipeline heat tracing, storage tank, instrument heat tracing and condensate pipeline antifreeze protection. However, it can not be applied to devices that require rapid discharge of condensate, such as steam main pipe, heat exchanger and other important steam equipment.