considerable amount of construction of the main objects in the oil refining, metallurgy, food industry is given the arrangement of technological pipelines.They play a crucial role in the functioning of strategic systems.Also, technological pipelines are used in agriculture, heating systems and many other industries.
Concepts
pipeline - a device designed for the transportation of various substances.It consists of pipe sections, connecting and valves, automation and fasteners.
What is the meaning of the concept of "technological pipelines?"The definition refers to them as a system of industrial enterprises, which are transported semi-finished and finished products, as well as a substance capable of maintaining the process.
Location pipelines
During laying it is necessary to carry out these recommendations:
- process piping must have a minimum length;
- system unacceptable sagging and stagnation;
- free access for process control;
- possibility of arranging the necessary materials handling equipment;
- ensure insulation for preventing ingress of moisture and retain heat;
- protect pipelines from damage;
- free movement of fire-fighting equipment and lifting mechanisms.
draft angles
Operation technological pipelines provides an emergency stop.To this end, the project lays the slopes that provide arbitrary empty pipe.The device provides the following technological pipelines inclination angle depending on the conveyed fluid (values are in degrees):
- gaseous medium: the direction of motion - 0,002, against him - 0.003;
- Flowing liquid substances - 0,002;
- acid and alkaline - 0,005;
- substances of high viscosity or bystrozastyvayuschie - to 0.02.
design may not provide a bias, then special measures must be provided for emptying the pipeline.
Preparations
Installation of technological pipelines must first be accompanied by the following actions:
- check all the details of the project and make the necessary changes.
- The degree of preparedness of building structures and designs of the installation.
- control the line equipment necessary fittings, elements and details.
- adopting a separate piping components and accessories, according to regulatory documents.
- check the readiness of the temporary sites for the installation work, equipped with lighting, power supplies for welding devices for work at height.
- observing the necessary recommendations on the production of industrial pipelines in accordance with safety regulations.
marking trails
This operation consists in transferring axes mounting fittings and compensators directly to the place where they will be laid technological pipelines.Determination of the place layout can perform the following tools:
- roulette;
- pitches;
- level;
- hydraulic level;
- patterns;
- triangles.
When a building structure is laid a large number of technological pipelines, significantly reduced the time allotted for counting, using special layouts.They provide a visual representation of the location of the lines of the pipeline in relation to the building structure.All the elements applied after marking verify with the project, and then proceed to fixing the support structures.
Installation of supports and fasteners
During arrangement of the foundation of the building it should be provided for laying the bolt holes, mounting supports.They can be made by mechanized equipment.During the installation of supports should be taken into account such recommendations:
- technological pipelines, which have a fixed support described above involve the installation of fasteners close to the apparatus and fittings.Installation pipes such support must be firmly fixed not allowed offset.The same requirements are met in relation to the clamp.
- mobile support mounted to the free movement of the pipeline to seamlessly extend it when the need arises.Also, it shall be the safety of thermal insulation in the potential movement of the extension.
- all established support industrial pipelines installer should check for compliance with horizontal and vertical.Provides for the possibility of deviation, which may not exceed those limits:
- intrashop pipelines - ± 5 mm;
- external system - ± 10 mm;
- slopes - 0.001 mm.
connection with the existing system
This requires special permits, as well as on-site must be present installer of industrial pipelines, which serves the lines.Carry out a frame when a new component is mounted is connected to the current system.Typically, in such cases it provides installation of locking devices, but if the current system there is no such, it resorted to the sidebar.There are several features:
- existing pipelines must be disconnected and empty.
- pipeline, which transported flammable and explosive atmosphere, certainly neutralized and washed.
- Weld nipple to pass preliminary tests.Also, the documentation set for the steel grade.
- Welding work necessarily holds a highly qualified specialist, having special access to critical structures.
- Before you begin to make installation of technological pipelines, connecting node has to pass all the tests.
purging and flushing the pipeline
collected is purified, the method is dependent on pipe size:
- diameter up to 150 mm - is washed with water;
- more than 150 mm - blown air;
cleansed area should be isolated from other lines of pipe plugs.Washing with water is carried out, is out of the tube begins to flow water without contamination.Purging is carried out for 10 minutes.These methods are used if the technology does not provide for other standards of cleaning.After work you can begin to test that are performed in two ways: hydraulic and pneumatic.
Hydrotesting
before checking process piping is divided into individual sections and conditional carry out the following activities:
- control by visual inspection;
- verification of technical documentation;
- installation of air valves, temporary plugs (constant use of equipment is forbidden);
- off test interval;
- test connection portion to the hydraulic pump.
Thus, it is checked at the same time the strength and density of the conduit.In order to establish the degree of strength is taken into account the special value of the test pressure:
- steel piping operated at operating pressures of up to 5 kg / m².The test parameter - 1.5 on the operating pressure, but not less than 2 kg / m².
- steel pipes, operating at a pressure that is greater than 5 kg / m².The parameter test will be 1.25 working pressure;
- cast iron, plastic and glass - 2 kg / m².
- pipelines of non-ferrous metals - 1 kg / m².
- For pipes made of other materials - 1.25 working pressure.
holding time at the established pressure value is 5 minutes, only for glass pipe is increased four times.
Pneumatic testing
To test using compressed air or inert gas, which is taken from the factory or from networks of portable compressors.This preferred embodiment, in cases where no hydraulic testing for several reasons: the lack of water, the very low temperature air, and also when the weight of water in the pipeline construction could be dangerous voltage.The value of the limit of the test pressure depends on the size of the pipeline:
- pipes with a diameter up to 200 mm - 20 kg / m²;
- 200-500 mm - 12 kg / m²;
- more than 500 mm - 6 kg / m².
If another pressure limit for such conditions should be developed special instructions for testing.
requirements for pneumatic testing
Pneumatic testing is prohibited for ground cast-iron and glass constructions.For all other materials that can be executed process piping, there are special requirements for the tests:
- line pressure is increased gradually;
- inspection can be carried out when the pressure of 0.6 times the operating current (to raise it in the course of work is unacceptable);
- check for leaks with soapy water made obmazyvaniem, tapping with a hammer is forbidden.
results of hydraulic and pneumatic test is considered satisfactory if the process of their implementation has not happened pressure drop on the pressure gauge.
transmission pipelines in operation
for all installation steps are compiled relevant documents, retaining jobs, tolerances, testing, etc.They are transferred to the stage of delivery of pipelines as the accompanying documentation, they include:
- acts putting support structures;
- certificates for welding materials;
- protocol internal cleaning of the pipeline;
- acts quality control of welded joints;
- conclusion on tests of valves;
- acts of strength tests and density;
- list welders, make connections, and documents proving their qualifications;
- circuit piping lines.
Technological pipelines shall be commissioned along with industrial plants and buildings.Separately can be rented only to interplant system.
Operating Guidelines technological pipelines
Periodic monitoring should include such operations:
- Technical condition during the visual inspection and non-destructive methods.Check
- areas subject to vibration, special instruments, determining its frequency and amplitude.
- Troubleshooting, which were recorded during the previous inspections.
Equally important is the safe operation of process pipelines, which ensures compliance with all the rules.
Monthly check the status of the system should cover the following:
- flanges;
- welds;
- insulation and coating;
- drainage systems,
- bearing mounting.
If leaks detected, for safety reasons the operating pressure must be reduced to atmospheric pressure and the temperature of the thermal line to drop to 60 ° C for the necessary measures to deal with problems.The results of the test must be recorded in special journals.
audit
This control method is used to determine the status and operational capacities of the pipelines.Advisable to carry out an audit on the areas where the exploitation of technological pipelines being in particularly difficult conditions.The latter include vibration, excessive corrosion.
audit pipeline includes such operations:
- Check the thickness of the structure non-destructive methods.
- measurement areas prone to creep.
- control of welded joints, which are questionable.
- Checking threaded connections.
- State support mounts.
first audit control should be carried out in a quarter of schedule in the regulations, but not later than 5 years after the start of the object.As a result of the timely conduct of inspections will ensure the safe operation of industrial pipelines.
