The working principle of a hydrophobic expansion vessel:
When the condensate from high-pressure boilers and other equipment enters the condensate tank, it is depressurized in an expansion tank (equipped with cooling water pipes), some of it vaporizes into steam. The non-vaporized, high-temperature water is cooled and then returned to the condensate tank for use, thereby reducing heat and steam losses. The steam can be sent to the plant's low-pressure steam network for utilization.
Usage
1. The desuperheater is designed to expand and reduce the pressure of the condensate from the pressure drain line, separating steam and condensate. The steam is then directed into a heat exchanger or deaerator to maximize its thermal energy, while the condensate is introduced into the condensate tank for regular addition to the feedwater system. Primarily, it serves to lower pressure; if high-pressure steam is directly fed into the condenser, it can lead to overpressure. This device can reduce pressure to prevent overpressure. Additionally, it contains a temperature-reducing unit to lower the temperature.
2. Mechanical-type (free floating ball, lever floating ball, inverted bucket) drain valves operate based on the principle of buoyancy. They can automatically distinguish steam and water and are commonly used in situations requiring continuous drainage with high flow rates, where the drained water is collected and reused. Among them, the lever floating ball drain valve and the inverted bucket drain valve have complex structures, while the free floating ball drain valve has a simple structure, does not leak steam, and is generally used for pipeline or equipment drainage.
3. The thermodynamic (disc-type, pulse-type) trap utilizes the principles of aerodynamics to switch valves through the pressure drop generated by the redirection of gas flow. It is suitable for applications with low flow rates, high differential pressure, and moderate continuity requirements. The structure is simple, but it exhibits pulsating leakage, typically used for pipeline drainage.
