Common problems in the use of pipes

In the city water supply, drainage, heating, gas pipelines and long-distance oil pipelines are mostly buried in the underground, and the factory in the process of the pipeline for the ease of operation and maintenance of more than laying on the ground. Pipeline traffic, supporting, slope and discharge exhaust, compensation, heating, heat preservation and antisepsis and cleaning, painting and other identification and safety, both for the ground or underground laying are important issues.

Traffic problem

Pipelines on the ground should be avoided as far as possible with roads, railways and waterways. In cannot be avoided when crossing the intersection across the height should also be able to make the safety of pedestrians and vehicles through. The underground pipeline laying along the road, keep a proper distance between the various pipelines, for the installation and maintenance; surface heating pipe insulation layer, laying in the gutter or protective tube, should avoid being crushed and the soil expansion movement.

Supporting problem

The pipeline may be subjected to many kinds of forces, including the weight (pipe, valve, pipe fitting, insulation layer and weight fluid tube), fluid pressure acting on the pipe end thrust, snow load, soil pressure, thermal expansion and contraction caused by thermal stress, vibration load and earthquake disaster etc.. In order to ensure the strength and stiffness of the pipeline, we must set up a variety of supporting frame, such as the active support, the fixed support, the guide bracket and the spring bracket, etc.. The bracket is arranged according to the diameter of the pipe, the material, the thickness of the pipe wall, the load and so on. The fixed bracket is used for controlling the thermal elongation of the pipeline, and the expansion joint is uniform. The guide bracket enables the pipe to move only axially.

Slope and drainage

In order to eliminate condensation water, steam and other water content of the gas pipeline should have a certain degree of slope, generally not less than 2/1000. For the use of gravity flow of underground drainage pipes, the slope is not less than 5/1000. Steam or other water containing gas pipeline at the lowest point set drainage pipe or trap, some gas pipeline also has a gas water separator, in order to discharge the water in time to prevent water hammer and hinder the flow of water. The water supply or other liquid pipeline is provided with an exhaust device at the highest point, and the air or other gas in the pipeline is excluded to prevent the running disorder caused by the air resistance.

Compensation problem

If the pipe is not freely retractable, it will generate enormous additional stress. Therefore, the temperature change of the pipeline and the need to have free movement of the room temperature pipe, the need to set expansion joints, so that the expansion of the pipeline to be compensated and the elimination of the impact of additional stress.

Heat preservation and heating

For the steam pipe, high temperature, low temperature and pipeline pipeline burn proof and anti freeze requirements in the pipeline pipeline, need to be coated with insulation material outside the tube, to prevent loss of heat (cold) or by freezing. For some high freezing point liquid pipeline, to prevent the liquid is too sticky or solidification and affect the transport, but also need to heat and heat insulation. Insulation materials are commonly used cement perlite, glass wool, rock wool and asbestos diatomite etc..

Corrosion protection and cleaning

In order to prevent soil erosion, the surface of the underground metal pipe should be coated with anti rust paint or tar, asphalt and other anti-corrosion coatings, or coated with impregnated asphalt, such as glass cloth and linen. The pipeline buried in the strong corrosion resistance of the low resistance of the soil should be set up a cathodic protection device to prevent corrosion. Steel pipes on the ground to prevent atmospheric corrosion, the surface coating with a variety of anti rust paint. All kinds of pipelines should be cleaned before use, and some of the pipes should be cleaned regularly. In order to convenient cleaning, filter or blow wash sweep holes are provided in the pipeline. In the long distance pipeline transportation of oil and gas, must use cleaner regularly to remove dirt accumulated inside the tube, to set up a dedicated device to send and receive cleaning device.

Identification of paint

When there are more types of pipelines, in order to facilitate the operation and maintenance, in the pipeline surface coated with a specified color paint, in order to identify the. For example, the steam pipeline with red, compressed air pipe with light blue, etc..

safety problem

In order to ensure the safe operation of the pipeline and the accident in time to stop the expansion of the accident, in addition to a detection control instrument and safety valve in the pipe, but also take special security measures on some important pipelines, such as the gas pipeline and long distance transportation of oil and gas pipeline is provided with a pressure relief valve accident or emergency cut-off valve. They can stop the transmission automatically and timely in the event of a disaster, so as to reduce the loss of disaster.