When choosing a steam trap, you cannot simply choose from a large amount of discharge. Special attention should be paid: "It is never allowed to apply traps based only on the pipe diameter". It must be selected according to the principle of trap selection and the specific conditions of the condensate system. In general, it should be selected according to the following three aspects.
1. First, select and determine the type of trap according to the heating equipment and the requirements for discharging condensate.
For heating equipment that requires fast heating speed and strict heating temperature control, it is necessary to keep condensed water in the heating equipment. As long as there is water, it must be drained. Choose a mechanical trap that can drain saturated water. Because it is a trap with water to drain, it can eliminate the adverse consequences caused by water accumulation in the equipment in time, quickly improve and ensure the heating efficiency required by the equipment.
For heating equipment that has a large heating surface and does not have strict control on heating speed and heating temperature, it can allow water accumulation, such as steam heating and drainage, and process heating pipeline drainage. You should choose a thermostatic trap as well.
For medium and low pressure steam transmission pipelines, the condensate generated in the pipeline must be quickly removed, otherwise it will easily cause water hammer accidents. The increased moisture content in the steam reduces the temperature of the steam, which cannot meet the technological requirements of steam-using equipment. Therefore, it is better to choose mechanical traps for medium and low pressure steam pipelines.
2. Secondly, according to the higher working pressure and higher working temperature of steam equipment, determine the nominal pressure of the trap and the material of the valve body; determine the connection method and installation method of the trap. The higher working temperature of the steam trap is determined by the steam used by the steam using equipment, and the selection should not be lower than the temperature of the steam used.
The trap has two installation methods, horizontal and vertical. It is determined by the connection position of the pipeline and the trap. The connection mode of the steam trap is thread, flange, welding, clamping, etc., which must be determined according to the higher working pressure, higher working temperature of the trap and the corresponding connection part requirements of the steam use equipment.
3. According to the size of drainage, select and determine the performance parameters of the trap.
In addition to the pressure, temperature and other parameters of the trap should match the conditions of the equipment used, the drainage volume of the trap under various pressure differences is an important factor in the selection of traps. If the drainage volume of the selected trap is too small, all the condensate that has reached the trap cannot be removed in time, which will cause the condensate to flow back, which will cause blockage and significantly reduce the heating efficiency of the equipment. On the contrary, the use of a steam trap with a too large displacement will cause premature wear and failure of the valve closing member. As the valve body increases, its manufacturing cost will increase, which is not economical. Therefore, the amount of condensate generated in the equipment or pipeline must be measured correctly or calculated according to the calculation formula to provide conditions for the correct selection of the trap.
Therefore, when determining the displacement of the steam trap, the "safety factor K" should be determined according to the characteristics of various steam equipment and the discharge form of the trap. Generally, it should be calculated according to the following formula: the hourly displacement of the trap = the amount of condensate produced per hour by the equipment or pipeline × the safety factor K
