The pipeline is not working well, and the compressor is exhausted

The pipeline is not working well, and the compressor is exhausted

Many users have invested a lot of energy and money in the selection, operation and maintenance of compressor equipment, but due to negligence on the compressed air pipeline, a lot of waste has been caused.

　　1 Selection of compressed air pipes

The atmosphere contains corrosive gases, water vapor, hydrocarbons and other impurities. There are about 140 million solid particles per cubic meter of air. More than 80% of these impurities have a particle diameter of less than 2μm. It easily enters the compressed air system through the air compressor and filter.

　　The air containing various impurities passes through a simple filter and then enters the air compressor for compression. Due to the high temperature and oxidation generated when the gas is compressed, the quality of the compressor lubricating oil is reduced, and it is strongly acidic. When these solid particles enter the compressed air pipe network system together with the oil and water vapor in the compressed air, such as the use of traditional galvanized pipes or carbon steel pipes, the inner wall of the pipes will be rusted first, because of its active iron Chemical properties are particularly easy to cause rust. When iron is in contact with air, it will chemically react with oxygen in the air, turning the molecules on the surface of iron into iron oxide-rust. The surface of the iron exposed to the air is constantly oxidized and rusted, making the iron soft and loose.

　　 Ordinary carbon steel pipes have been used for a long time. Corrosive impurities will naturally deposit inside the pipes. The final result is that the pipeline (including the location of the weld) is corroded and leaked. The contaminated air will cause serious damage to the quality of pneumatic equipment, pneumatic instruments and terminal products, increase the maintenance cost of the system equipment, and directly waste the leaked compressed air. A lot of electrical energy. Practice has proved that the heavy, polluting and leak-prone seamless steel pipes and galvanized pipes are slowly being eliminated, and the PVC pipes with more safety hazards are also slowly moving away from the industry, replaced by new full-performance aluminum alloy compression The air pipeline, with its superior materials and production technology, can ensure the delivery of high-quality and pure compressed air, protect the safety of the air terminal and stable output quality. The high-performance O-ring seal can effectively prevent leakage, but it is relatively expensive.

　　2 Design and installation of compressed air pipes

　　The compressed air transmission pipelines of all domestic factories and enterprises are straight, one-way pipelines, which will cause the front-end jobs to work normally, and the back-end jobs will have insufficient pressure and flow supply. In addition, during the installation design, the setting of the control valve in the segmented area was not considered, and the failure of one area or one equipment would cause the entire plant to stop production and work. During installation, the issue of drainage is rarely considered. The compressed air pipelines of many companies are very messy. Some are flying in the air or buried underground. They are complicated and unable to drain.

　　 There are also some manufacturers that use PVC or PPR as the conveying pipes. Because of their large expansion rate, they did not consider the problem of expansion ports. Therefore, when designing and installing compressed air pipelines, it is necessary to have pressure pipeline qualifications and professional design and installation and company design, planning and installation. In order to ensure the normal operation of production enterprises, improve efficiency, reduce costs, and ensure quality.

　　3 Precautions for installation of compressed air pipeline

　　 (1) The pipes, fittings and valves can be installed only after they have passed the inspection and checked according to the design requirements.

　　 (2) All pipe supports and hangers are finished products, and the specific quantity is calculated by the contractor. 　　 (3) The pipeline used for flange connection can be installed twice, that is, after the flange is welded to the pipeline, it is disassembled, corrected, cleaned and reinstalled.

(4) Small pipelines that are not shown in the piping layout diagram, including instrument pipes, etc., whose orientation is determined during on-site construction, should be neatly arranged and have a reasonable orientation, and should be installed in accordance with the requirements of engineering regulations and design documents after other pipelines are installed. Install it.

　　 (5) The finished product protection should be done during the installation of the pipeline, and it is strictly prohibited for gloves, bolts, welding materials and other sundries to fall into it.

　　 (6) All rust-proof accessories must be treated with rust prevention and appropriate rust-proof paint. At the same time, during installation, the electrolysis caused by the direct contact of different metals should be prevented.

　　(7) The pipes should be fixed with brackets, especially the pipes with flexible joints and the pipes that do not allow load-bearing, they should be fixed with additional brackets.

　　 (8) z*The distance between the support of large pipelines cannot exceed 5 meters. The actual layout and details are provided by the design requirements and parameter table, and submitted to the project management and the owner for approval.

　　 (9) Non-insulated power pipeline supports generally use curved pipe supports, but in order to prevent accidental fall off of the pipeline due to radial displacement in the horizontal direction, sliding supports should be installed about every 24m.

　　 (10) After removing the rust and dirt, the pipe supports, supports and parts shall be painted with anti-rust paint twice, with one gray finish.

　　 (11) Welding of supports and hangers shall be performed by qualified welders, and there shall be no defects such as missing welding, under welding or welding cracks. When the pipe is welded to the bracket, the pipe shall not have undercut or burn through.

　　 (12) The circumferential weld of the pipe shall not be placed on the support, and the distance from the edge of the support shall not be less than 200 mm, and the longitudinal weld of the welded steel pipe shall be oriented in a direction convenient for inspection.

　　 (13) When the compressed air pipeline is threadedly connected, each branch pipe should be provided with a union near the threaded valve and other maintenance parts to facilitate maintenance.

　　 (14) After installation, compressed air pipelines with a design pressure greater than 1.0 MPa should be sampled and radiographically inspected. The sampling rate should not be less than 5% and the quality should not be less than Class III.

　　(15) The strength test of the piping system should be carried out after the power piping is installed. When the pneumatic test is adopted, the test pressure of the low-pressure system is 1.15MPa, and the test pressure of the high-pressure system is 1.61MPa. The test medium is dry and clean air, which shall be approved by the construction unit before the test. At the same time, safety protection and isolation measures shall be taken during the pressure test.

　　 Before the test, air must be used for pre-test. During the test, the pressure should be gradually increased slowly. When the pressure rises to 50% of the test pressure, if no abnormality or leakage is found, continue to increase the pressure step by step at 10% of the test pressure, and stabilize each step for 3 minutes until the test pressure. Then stabilize the pressure for 10 minutes, and then reduce the pressure to the design pressure for inspection, and the foaming agent is qualified if it does not leak.

　　 (16) The contractor shall submit the pressure test plan to the project management party and the owner for approval before the pressure test.

　　 4 pipeline compressed air failure and solutions

　　(1) The safety valve leaks

　　 The bearing surface of the safety valve spring is not perpendicular to the spring centerline. When the center line of the valve spring is not perpendicular to the supporting surface, and the valve spring is compressed, it will deflect, causing uneven force on the disc of the safety valve, warping, causing air leakage, oscillation, and even failure of the safety valve.

　　Solution: Adjust the verticality of the spring support surface of the safety valve to the center line of the spring to keep them perpendicular to each other, clean up the impurities and dirt between the safety valve and the valve seat, and re-grind if necessary to ensure a tight contact surface. The valve spring of the safety valve should be pressed tightly, the thread and the sealing surface should be protected, and the damaged part should be repaired and ground.

　　(2) Air leakage in piping system

　　 The cause of air leakage is often due to poor quality of materials and accessories or poor installation quality. The sinking of the bracket in the pipeline causes serious deformation and cracking of the pipeline, and the accumulation of water in the pipeline will cause the pipe or fittings to burst and crack.

　　Solution: repair or replace damaged pipe sections and fittings, regularly remove the water in the pipeline to prevent freezing and cracking; when the pipeline support sinks, the support should be repaired, and the slope of the pipeline should be adjusted to facilitate drainage.