Classification of foam pigs and principle of pipeline pressure test
Foam pigs are a common tool for cleaning pipes, so what is the classification of foam pigs? What are the principles to be followed when testing pipelines? Today, the editor will explain in detail the classification of the foam pig and the principle of pipeline pressure test. I hope to help everyone. The details are as follows.
What are the classifications of foam pigs?
According to the raw materials used for foaming: polyether foam (sponge), polyester foam (high-density polyurethane foam ball), tetrahydrofuran foam, etc., commonly used in pipelines are polyether foam (sponge), and polyester foam ( High density polyurethane foam balls).
The foam pig is subdivided according to the functions and characteristics: polyether (sponge) absorbent foam ball, fully coated foam ball, shaped coated foam ball, polyester foam ball (high density polyurethane foam ball)
Polyether foam (sponge) is now routinely used in China. If pure raw materials are used without filler, the highest density is about 30 kg/m3. The advantage is low density and good water absorption. The wear-resistant coating can be used to complete the pigging. Features. The disadvantage is that it is fragile and long distance is not suitable for application. Polyether foam (sponge) high density generally uses filler (calcium powder) to adjust the density. After adding filler, the product is brittle and generally not suitable for pipeline applications.
Nowadays, polyester foam is conventionally used in foreign countries, and the density is generally above 250 kg/m3. The advantage is that it is well worn and not broken. The disadvantage is that the water absorption performance is not as good as the low density sponge. Uses: Suitable for pipeline cleaning applications, especially for long distance and subsea pipeline applications.
Pipeline pressure test principle
When the pipeline is pressure tested, all equipment (machine pumps, filters, storage tanks, heat exchangers, etc.), valves (regulating valves, shut-off valves, pigging valves, safety valves, etc.) or pipelines that cannot participate in the pressure test must be in the system. If it is isolated and cannot be isolated, it must be approved by the design unit and the construction unit before participating in the system pressure test. The system test pressure should be the test pressure of the entire system with the test pressure of the pipeline with the highest design pressure. The pressure test of the series system should first test the pipeline with lower pressure grade, then cut out the low pressure system section by section and then test the pressure of the system with higher pressure grade. The pipeline pressure test program first supervises the rear branch pipe, and then performs the sequence of the drain and drain pipes, presses the pressure according to the number, and then carries out the pin number according to the test pressure package.
The above is about the type of foam pig and the principle of pipeline pressure test. I hope that everyone can understand the type of foam pig and the principle of pipeline pressure test, which will help everyone clean the pipeline.
