Spring mechanical seals

One of the types of mechanical seals is spring seals, such seals include secondary seals called a dynamic gasket that are pushed axially by a spring along the shaft or sleeve to compensate for wear or an unstable position of the seal working surface due to inaccurate alignment during installation.

Spring seals, with the exception of models for high loads, are generally less expensive than bellows designs and are available in a larger assortment of sizes. The spring seal is often chosen for light hydrocarbons, high pressure levels and high-speed applications, due to the higher strength of this type of seal construction and the stronger axial damping action of the dynamic gasket. However, the spring seals do not provide for the use of graphite gaskets, as a result of which the maximum temperature values ​​are limited by available elastomer or PTFE gaskets. The chemical effect on the gasket material can also be a limiting factor. In addition, the build-up of material in connection with the infiltration of liquid on the working surfaces of the seal can prevent axial movement along the shaft, thereby reducing the ability of the seal to compensate for wear on the face (hang effect).

The most common design of the spring assembly is a set of small springs made of a material with high corrosion resistance. To protect these small springs from contamination in some designs, the springs are placed outside the product. The use of one large spring as an alternative is more suitable for harsh environmental conditions and a contaminated product. The latest commonly used design, known as the "wavy spring", makes it possible to realize very compact products in the axial direction.

Advantages of spring mechanical seals:

- universality;

- low cost of the product;

- high pressure;

- high speed;

- axial damping action of the gasket, possibility of application for light hydrocarbons.

Lacks of spring mechanical seals:

- restrictions on the material and temperature of the gasket;

- increased sensitivity to hovering.

Examples of spring mechanical seals.

Single unloaded multi-spring seal, used as a universal, mainly in the chemical industry.

It can be used as an internal or external seal under the conditions of exposure to abrasive and corrosive materials.

Individual parts are completely interchangeable and easily replaced.

A typical example of this type of seal is NV-3 Mechanical seal with wavy spring, which is an analog of such mechanical seals as: AESSEAL W07D / W07DM, Burgmann M7N, Vulcan 1677, Sterling 270, Flowserve Europac 600, and completely with them interchangeably.

Double friction single-spring seal, which can be used under moderate pressure conditions when pumping water or other product of similar viscosity. The quality of the seal depends on the amount of frictional force between the dynamic gasket and the pump shaft. The metal seal parts are insulated from the pumped product in order to prevent possible chemical or abrasive effects. Very easy to install.

Unloaded rotating single-spring seal for applications with high load and conventional modes. The seal has sufficient flexibility and tolerance to compensate for minor inconsistencies between the shaft and the bearings, including the rotating surface of the most modern silicon carbide structure with graphite gasket. The sealed working surface of the seal ensures an optimal flatness of the working surface to control low emissions.

Unloaded rotating single-spring seal for energy or other high pressure applications.

Single unloaded multi-spring seal with external installation of springs in order to prevent their clogging. The working surfaces are made of silicon carbide. Accurate arrangement of parts and large gaps between the seal and shaft sleeve, robust construction.

Single unloaded multi-spring cartridge seal, specially designed for operation under abrasive materials. The unique design provides the impact of the pumped product on the work surfaces in order to maximize heat transfer and eliminate the traditional causes of malfunction. The special casing protects the compression springs in the stationary sealing area and the rotor drive pin from the formation of the build-up due to leakage of the product. The design of the preinstallation cartridge and the presence of centering pins simplify the installation of the seal.

To order mechanical seals, it is sufficient to know the brand of the pump or the serial number of the seal.