When it comes to testing compensators, there are two main methods: pneumatic (air pressure) and hydraulic (water pressure). As the names imply, both involve filling the compensator with a fluid-usually water for hydraulic tests-or gas, then applying pressure to the required test level. Hydraulic testing is the standard go-to since pneumatic testing carries more risk. If you do use air pressure, make sure to have proper safety measures in place. A typical pressure test for compensators involves hitting 1.5 times the design pressure with water; for air tests, you only need to go up to 1.1 times the design pressure. (Note: Metal bellows within compensators play a critical role in withstanding these pressures, especially in hydraulic setups.)
Now, let's talk about a new type of compensator for thermal pipe expansion: the rotary compensator. It's basically made up of an integrated seal seat, seal gland, reducer, friction-reducing centering bearings, sealing material, and a rotating cylinder. When installing these on thermal pipelines, you'll need at least two of them grouped together to form a pair. They work by rotating relative to each other to absorb the pipe's thermal movement, which helps reduce stress in the system.
Metal compensators usually consist of a flow guide tube, bellows, flange, and tie rods. The first thing you need to figure out when making one is the bellows material, which depends on the medium being transported and the temperature. Most of the time, we use stainless steel for metal compensators because it's great at handling heat, pressure, and corrosion-all key to making sure the compensator lasts. There are different stainless steel grades to choose from, like 304, 316L, 321, and 310S. Each has a different heat resistance level, so we pick the right one based on the specific conditions of the pipeline.
