The Research To The Affecting Factors Of Water Seal Keeping Ability In Trap

Drainage system inside building acceptance of the displacement is relatively small, uneven, drainage for short. The peak flow may be full of the whole pipeline section. Most of the time may not have the water in the pipe. Water and air mixed easily, so the free water surface and air pressure in the pipe is not stable, and it's easy to cause a pressure wave. If the building drainage not free, the sewage will spillover to the indoor ground from the drainage pipe, and the toxic or harmful gases will go into the room to produce pollution when the air pressure in the drainage pipe is beyond the range.Since the 20 th century, scholars both at home and abroad have done a lot of experiment researches about water seal height, the regulation of water seal height in different countries are also different. At the same time, in order to explore the effect on the height of water seal caused by the system pressure fluctuations, scholars both at home and abroad have done a seris of experiment researches about the pressure fluctuations in drainage pipe. But the researches from the perspective of S-shaped trap structure, which to explore the water seal height affecting factors is less, and started late.Test object is the S-shaped trap and its water seal height in the high-rise building drainage system. This research used stack vent drainage system and drained constant flow. At first made several groups of different flow drainage experiment in the system which uninstalled S-shaped trap, to find out the large negative and positive pressure floor which the pressure was relatively stable when drained constant flow. Second installed different diameter or different angle of S-shaped trap on the lager negative / positive pressure floor's horizontal pipe, then made different flow and different drainage length test. Record the pressure fluctuations within the stack vent drainage system and the water seal height volatility in the S-shaped trap. Analyze the water seal height difference before and after the drainage. Determine the influence of diameter, angle, drainage length and other factors on the performance of water seal against pressure fluctuations.Conclusion: From this research, when install the same S-shaped trap and drain the same constant flow, the water seal height loss is largest when drain 120 s. When drain the same constant flow 120 s, the water seal height loss in the S-shaped trap decrease with the increase of the middle tube's diameter. The water seal height loss is minimal when the middle tube diameter is 80 mm in this experiment. So suggest when conditions permit, use the trap which the middle tube's diameter is larger to improve its water seal keeping ability. When drain the same constant flow 120 s, the water seal height loss in the S-shaped trap decrease with the increase of the angle between the middle tube and the horizontal direction. The water seal height loss is minimal when the angle between the middle tube and the horizontal direction is 90 °in this experiment. So suggest continue to use the S-shaped trap which the angle between the middle tube and the horizontal direction is 90 °to improve its water seal keeping ability.