When there is a difference between the loads across the seal faces, it is called a condition of an unbalanced mechanical seal. When any of the faces has too high a load, the liquid film between the seal ring might get squeezed out or vaporized.
This is an unstable condition from thermoelastic instability, and it could result in a higher wear rate of sealing surfaces.
Balanced Mechanical seals do not have any of these issues. There are several reputed brands like Leak-Pack that offer a wide variety of balanced seals.
A balanced seal is designed to operate with the shoulder. The only exception is the metal bellows seal that does not require a shoulder.
Balanced mechanical seal -some advantages
In a balanced seal, the load acts across the seal faces. This load between the seal faces has to be optimum in this case. When the load is exceptionally high, the liquid film gets oozed out.
- Vaporization of this liquid results in creating unstable conditions. In a balanced seal, the biggest benefit is that it saves energy. Also, the life of this seal is longer as compared to an unbalanced seal.
- The pressure in a balanced seal is equally applied in all directions. The pressure keeps the primary ring stable against the rotating or mating ring. It is possible to lower the pressure by reducing the diameter of the shoulder on the sleeve. This can be done by decreasing the seal hardware.
- The face area or opening area of a balanced seal is equal to an unbalanced seal. However, the closing area is always maintained according to the face area.
- If there is a reduction in the closing area, then the closing force also reduces in the same proportion. Thus, less heat is generated. As a result, the life of the seal gets extended.
- Balanced seals can handle high capacities of poor lubricity fluids. Therefore, these seals are more suitable and useful for industries related to light hydrocarbons.
- Since there are many springs in multi-spring seals, the force is uniform over the faces. This seal type is easy to maintain and economical because the components are interchangeable.
Multi Spring-Balanced Seals are popular today
Multi Spring Balanced Seals are useful when you need high-pressure sealing in your application. They are quite compact in design. Therefore, these seals are suitable for various types of rotating equipment, e.g., pumps and mixers.
There are drive lugs in the retainer to provide torque transmission and reduced slippage on the shaft and sleeves.
Multi Spring Balanced Mechanical Seals are available in different arrangements- single, double, or tandem arrangement with external seals support systems and devices.
In Multi Spring Balanced Mechanical Seals the bellow faces are replaceable as well as interchangeable.
These seals are considered suitable in Clear Lubricating, Non-Corrosive and volatile types of liquids. Also, they are perfectly suitable for costly and volatile liquids, or liquids that are hazardous and toxic in nature.
You can choose between the wide range of balanced mechanical seal available in the market.
Read More: components of a mechanical seal