Where does the slope of steam pipes come from?

This post was last edited by ylb913 on 2015-8-21 at 18:49. 1. Indeed, the source of this information cannot be found; however, it is necessary to control the flow direction of steam pipes in order to avoid dead zones that could lead to excessive temperature drops. Venting devices are installed along the steam pipelines, and traps should also be present. In practice, when the traps at many locations break down, they are removed so that some venting can take place, or sometimes no venting is allowed at all. 2. Regarding the slope issue, our factory has a higher elevation in the south and a lower one in the north; I’m not sure about other areas, but at least in our workshop, the steam is drawn from the northern part and flows upward to higher elevations. The slope there is far more than 0.3%, and there are also several gantries along the way. In fact, the steam in the system’s pipelines is superheated, so condensation does not occur easily. Steam pipes shall be arranged in accordance with the following requirements: a) Steam branch pipes shall branch off from the top of the main steam pipe, and the isolation valves on these branch pipes shall be installed on the horizontal section of the pipe close to the main pipe ； b) A demister should be installed at the end of the steam main ； c) The spacing between demister units on horizontally installed main steam pipes is specified as follows: within the plant, it should be 80 m for saturated steam, and 160 m for superheated steam ； Outside the facility, it should be 300 m when going uphill, and 200 m when going downhill ； d) No branch pipes shall be connected from steam pipelines with strict steam requirements for other purposes ； e) The fire steam for each zone shall be supplied separately from the main pipe; it is not allowed to use the same steam branch pipe for both fire steam and purging steam ； f) At the lowest point of the steam branch, a drain valve or steam trap should be installed depending on the specific circumstances ； g) No branch pipes shall be led out from the \"mouth\"-shaped compensator on the steam pipeline. When branch pipes are led out from the straight sections adjacent to both sides of the \"mouth\"-shaped compensator, these branch pipes should not hinder the deformation or displacement of the main pipe. The displacement of the branch pipe outlet caused by thermal expansion of the Supervisor should not subject the branch pipe to excessive stress or excessive movement ； h) Multiple steam tracing pipes should be arranged in groups and equipped with distribution pipes; the steam for these distribution pipes should preferably be taken from the main pipe at a nearby location ； i) For steam vent pipes that discharge directly into the atmosphere, a drainage hole of F6 mm size should be provided near the elbow at the lower end of such pipes, and a DN15 pipe should be connected to lead the liquid to a suitable location such as a drain or funnel. If a silencer is installed on the vent pipe, a DN15 drain pipe should be provided at the bottom of the silencer and connected to the vent pipe. The vent pipe should be equipped with guiding and load-bearing supports ； j) Pneumatic pipes that discharge continuously or frequently should be led to areas that are not part of the main operational zone and where there are few operators.

Please check @wwxxjj’s related post at http://bbs.hcbbs.com/thread-1373104-1-1.html. What should be the slope of the steam pipes? Why?

The installation team said that there’s no need to consider the slope of steam pipes. That doesn’t make sense. Condensate can be drained by applying pressure

A slope in the steam pipes is necessary, right?

When to use a slope-following approach and when to design a slope-contrasting one? Is it related to the length of the pipeline? Or other factors