Non-cartridge mechanical seals are a traditional structural form of mechanical seals. Compared with cartridge mechanical seals, their core feature is that each component needs to be installed and debugged separately. In the sealing systems of rotating equipment such as industrial pumps, compressors, and agitators, non-cartridge mechanical seals are still widely used due to their flexible structure and low cost.

I.Structural Features
The core components of non-cartridge mechanical seal need to be assembled separately, mainly including:
(1)Rotating ring: rotates with the shaft and forms a sealing surface (friction pair) with the stationary ring;
(2)Stationary ring: fixed on the equipment end cover (such as pump cover) and does not rotate with the shaft;
(3)Elastic elements: such as springs (single spring, multiple springs), bellows, etc., used to compensate for the wear or axial displacement of the rotating ring and ensure the fit of the sealing surface;
(4)Auxiliary seals: such as O-rings, V-rings, wedge rings, etc.;
(5)Transmission parts: such as transmission pins, set screws, etc., transmit the rotational force of the shaft to the rotating ring (to prevent the rotating ring from slipping).

These components do not have a unified prefabricated housing or positioning reference, and need to be assembled one by one to the corresponding positions of the shaft and the end cover during installation, relying on the installer to adjust the matching accuracy of each component.

II. Installation and commissioning features

The installation of non-cartridge mechanical seals requires high operating skills, which are mainly reflected in:

1.Step-by-step assembly: the stationary ring, rotating ring, spring, auxiliary seal, etc. need to be installed in sequence. The installation order and position of each component must strictly follow the drawings, otherwise it may cause problems such as dislocation of the sealing surface and uneven force on the spring;

2. High positioning accuracy requirements:
The sealing surfaces of the rotating ring and the stationary ring must be kept perpendicular to the axis, otherwise it will cause local wear to increase;
The compression of the elastic element needs to be precisely controlled. Too tight will increase friction power consumption, and too loose will not ensure that the sealing surface fits, resulting in leakage;

3. Dependence on manual adjustment: After installation, the flexibility of the rotating ring (to ensure no jamming) and the compression of the seal need to be manually checked. If necessary, the position of the stationary ring should be adjusted by the thickness of the gasket, which takes a long time.

Non-cartridge mechanical seal is a traditional "distributed, manually assembled" sealing structure. Its core advantages are low cost and high flexibility, but it is limited by installation complexity and reliance on operating skills. In modern industry, with the increasing demand for automated installation, cartridge mechanical seals are increasingly widely used, but non-cartridge mechanical seals still play an irreplaceable role in specific scenarios.

Dandong Runhe Seal Co., Ltd. is a technology - based enterprise specializing in the design, R & D, production, and technical service of mechanical seals and seal auxiliary systems. The company has strong capabilities in the production and design of both cartridge mechanical seals and non - cartridge mechanical seals. With its excellent production and design capabilities, the company can not only provide standard products but also customize various mechanical seal products according to the special requirements of customers, and has won a good reputation in the industry.