Balancing Seal Pressure

Counterbalancing the pressure on the seal reduces the load and wear to a minimum

NextSeal™ is a technology that balances the pressure around the seal, making the pressure differential over the seal negligible. This “pressure balancing” has two appealing characteristics.

First, it stops the gas from leaking by letting the seal act only as a separator of gas and liquid with the same pressure. Second, it reduces the friction caused by the seal running against the opposing surface. This results in both less leakage and less friction where one traditionally had to choose on or the other.

The balancing can adjusted to fit the specific application, but as an example for the sake of illustration, the pressure balancing can be performed using a piston ring – a common seal*.

How it works

When the gas pressure inside the machine’s working chamber increases, the pressure on the seal automatically forces it against the liquid side.

As the liquid volume decreases, its pressure increases quickly until gas and liquid pressures are equalized. The physical characteristics of liquids makes the replication in pressure more or less instantaneous.

When the gas pressure inside the machine’s working chamber decreases, the liquid pressure on the seal automatically forces it against the gaseous side.

The seal moves up, the liquid flow out beneath the seal. The outlet flow of liquid decreases the liquid pressure making it replicate pressure of the gas instantaneously.

Now, what happens with the liquid? Didn’t we replace one problem with another?

That is actually exactly what we did. Now, instead of a gas sealing problem, there is a liquid sealing problem that needs to be solved.

Air would leak at a rate of 2166 times greater than water. The difference between gas leakage and liquid leakage would have the same order of magnitude no matter what gas or liquid is chosen.

This means that the so-called ‘sealing problem’ doesn’t extend to liquids. A bigger gap between the parts in motion can be given for the liquid and the small amount of leakage that will be passing the so-called ‘liquid seal’ is still small enough to be easily kept and recirculated within the NextSeal system.


*Piston seals are only one type of seal the NextSeal technology applies to, other types are rotary seals, reciprocating and rotating shaft seals.