1. According to the actual use of conditions to determine the steam inlet and outlet pressure drop. Steam trap inlet pressure is due to fluctuations in steam pressure or temperature regulating valve throttling, steam trap inlet minimum working pressure; steam trap outlet pressure refers to the steam trap may form the highest back pressure When discharged into the atmosphere, the actual pressure difference is determined by the steam trap inlet pressure. 2. According to the amount of condensate generated by the steam heating equipment during normal operation, multiply by the correction factor k and select it according to the displacement of steam traps. 3. The amount of condensate can be calculated by the following method: (1) The amount of condensate generated during pipeline operation Q = q0L (1-Z /%) (kg / h), where Q is the amount of condensate (kg / h) : The amount of condensate produced by the light pipe (kg / h) L: the distance between the hydrophobic points (m) Z: heat preservation efficiency (%) (2) The amount of condensate generated during operation of the steam heating equipment Q = VrCΔT / Ht, In this equation, Q is the volume of condensate (kg / h) V is the volume of the heated object (m3) r is the density of the heated object (kg / m3) C is the specific heat of the liquid (kcal / kg.OC) : Liquid temperature (OC) H: latent heat of steam (kcal / kg) t: heating time 4. The following table 1 recommended the use of common conditions of use of the value of the correction factor K for user reference. 5. Various types of steam traps structure and principle is different, the performance of different fluids, when used according to different occasions, choose different steam traps.