Pressure drop and \"surge\" problems in float-type steam traps
Thread Content
The drainage capacity of a float-type steam trap is directly proportional to the diameter of the drainage hole and the pressure difference across it; therefore, as the pressure difference decreases, the drainage volume also decreases. However, as the pressure difference between the upstream and downstream sides further decreases, to the point where the backpressure equals the inlet pressure or even exceeds it, the steam trap will enter a \"surge\" state. Is this understanding correct? It seems a bit strange to me, but I’m not sure what’s wrong with it :o
This post was last edited by Watt Energy Saving on 2017-5-22 at 16:15. The relationship between the drain valve nozzle and flow rate is one of square roots; as the pressure difference decreases, the discharge volume of the drain valve also decreases. When the pressure difference drops to a certain level, the discharge volume of the steam trap is almost zero. When the pressure at the inlet of the steam trap is lower than the back pressure, the steam trap experiences \"stall,\" and it is unable to discharge condensate properly. In practical applications, when backflow occurs in the steam trap, water accumulation in the heat exchanger leads to a reduction in heat output. As a result, the opening of the steam temperature control valve increases, and the higher steam pressure helps to overcome the backpressure; the steam trap then increases its discharge volume to restore thermal equilibrium.
Thank you for your reply. However, when the back pressure on the steam trap is too high, in the case of a float-type steam trap, the outlet nozzle remains pushed open and cannot be closed. Will this situation occur? Question: o
This post was last edited by At the foot of Hengshan Slope on 2017-5-23 at 15:11. Generally speaking, if a closed condensate system is connected downstream of a float-type steam trap, or if there is some backpressure, a check valve (one-way valve) must be installed downstream of the steam trap. The function of a check valve is to eliminate or reduce the impact of dynamic backpressure on the steam trap, but it cannot prevent static condensate from penetrating into the steam trap under high backpressure. Since the steam trap operates on the basis of a positive pressure difference, the design of the condensate system must ensure that a positive pressure difference exists at the steam trap under all operating conditions. If it is not possible to ensure that the steam trap always operates in a positive-pressure environment, then open discharge of condensate after the steam trap is required, with an intermediate pump used to recover the condensate. If connection to a high-backpressure condensate system is necessary, a steam trap and pump combination can be used to ensure hassle-free drainage from the heat exchanger in any condition. Great care must be taken when selecting the main condensate pipe. If there is concern that leaks in the steam traps could lead to an increase in back pressure in the condensate system, safety valves and overflow valves can be installed in it to maintain stable pressure levels.
In our factory, the medium-pressure condensate generated by the steam equipment passes through a steam trap before entering the low-pressure boiler to produce low-pressure steam. During this process, the steam trap failed. Personally, I think it is related to the hydrophobic system
I would like to ask – I think the trend charts for pressure difference and water drainage volume like this are incorrect. The relationship between the two is not linear; it is a square-root relationship. Moreover, at low pressure differences, the water rejection rate should not be so high. What do you think? ? ?
The pressure difference in the drain valve displacement diagram does not change in equal increments. So the curve was flattened. Ultra-low pressure and zero-pressure differential displacement take into account the minimum installed static head.