Common Types and Selection Guidelines of Pipe Plugs

According to structural design and working principles, pipe plugs are mainly divided into four types: threaded pipe plugs, push-fit pipe plugs, expansion pipe plugs and flange pipe plugs. Each type has unique performance and applicable scenarios. Threaded pipe plugs are the most common in industrial environments. They rely on threaded occlusion to achieve locking and sealing, featuring high precision, good pressure resistance and reusable performance. Common thread standards include NPT, BSPT and BSPP. Tapered threads have self-sealing ability and are suitable for medium and high-pressure working conditions in chemical, petroleum and pneumatic systems. Parallel threads require gaskets or O-rings and are mostly used for low-pressure water and air pipelines.

Push-fit pipe plugs are generally made of plastic, with simple structure and convenient installation. They are fixed by interference fit and do not require threading or tools. This type is low in cost and mainly used for dust prevention, port protection and low-pressure static sealing. It is widely applied in furniture pipes, light machinery and ordinary civil pipelines. However, due to poor pressure and temperature resistance, push-fit plugs are not suitable for high-pressure and high-temperature industrial environments.

In actual selection, several key factors must be considered. First is size matching. Selection cannot depend only on nominal diameter. Actual inner diameter, thread pitch and tooth type must be accurately measured to ensure effective fitting and sealing. Second is pressure grade. Low-pressure scenarios adopt plastic push-fit or rubber expansion plugs; medium and high-pressure environments require threaded tapered pipe plugs; large-diameter high-pressure pipelines must use flange plugs.

Third is temperature adaptability. Different materials have different temperature resistance ranges. Plastic materials are only suitable for normal temperature environments, while stainless steel and carbon steel can adapt to high temperature and low-temperature cold conditions. Fourth is medium compatibility. Water and air environments can use ordinary materials, while chemical corrosive media require 316L stainless steel or corrosion-resistant engineering plastics to prevent chemical erosion.