There are various types of inflatable sealing rings, including circular, rectangular, square, trapezoidal, D-shaped, C-shaped, V-shaped, and M-shaped. These sealing rings are primarily used for the following scenario:
Sealing gaps between large doors and hatches. These doors typically have a larger circumference, and due to machining and assembly precision or environmental temperature changes causing thermal expansion and contraction deformation, the gaps requiring sealing may vary or be inconsistent. The variation range is generally between 3-5mm or even greater, making it difficult to achieve ideal sealing with ordinary seals. In such cases, a sealing product that can adapt to the gap changes is needed; the inflatable seal is a new type of sealing technology developed to meet this sealing requirement.
Frequent opening and closing of pipeline ports and valves, particularly evident in dust pipes in the power and chemical industries, which require regular opening and cleaning before being closed. These pipes are typically over ￠300mm in diameter, and using flange covers with standard sealing washers and bolts to secure them adds significant maintenance time and installation difficulty. However, using an inflatable sealing ring can resolve all these issues, requiring only a minimal number of bolts, or even just clips, to secure them in place.

Automated canning of powdered food in plastic bags. An inflatable sealing ring is installed at the canning port. After the plastic bag is placed, the sealing ring inflates to tighten the bag. Once the canning is complete, the air is released, and the plastic bag automatically detaches. This greatly improves the canning efficiency in such cases.
Principle of Inflatable Sealing Ring
The sealing ring, naturally sealed and flexible, is hidden within a groove. When air is pumped into the sealing ring through a nozzle, it deforms under internal pressure, causing the central portion to swell outward and tightly contact the opposite sealing surface, thereby achieving a sealing effect. To release the sealed state, the high-pressure gas inside the sealing ring is expelled through the nozzle. The swollen portion, due to the rubber's elasticity, automatically retracts back into the groove, detaching from the sealing surface.
Important Precautions for Inflatable Sealing Rings
Air-filled sealing rings are generally installed in grooves. Attention should be paid to ensure that the sealing ring is completely concealed within the groove to prevent damage to the seal during the opening and closing of the cabin door.
The air compressor for the inflatable sealing rings must be equipped with a pressure relief valve. During the initial use, the inflation pressure typically starts at 0.1 MPa and gradually increases until the sealing effect is achieved, without exceeding 0.6 MPa.
The Evolution of Inflatable Sealing Ring

An inflatable sealing ring is a sealing technology achievement used under specific conditions. Due to the high import costs in the early stages, it has not been widely adopted domestically, which is one of the reasons for this. The manufacturing process of the finished product is complex, requiring high-quality materials, resulting in a low pass rate. Additionally, the cross-sectional shape, circumference dimensions, and direction of the circumference vary for inflatable sealing rings used in different scenarios. Each specification of the inflatable sealing ring requires the design and manufacturing of a large mold, thus significantly increasing production costs. Currently, Shanghai Qingtu Rubber Technology Co., Ltd. has broken through the monopoly and successfully researched a segmented molding and curing technology for large inflatable sealing rings, which can be manufactured using small molds to produce large inflatable sealing rings with infinite circumferences.