Using the Waveline WLP process, KLINGER A. W. Schultze has launched a gasket that has been proven to reduce leakage in hydrogen applications – including case example on savings potential.
Reliably minimizing leakage in hydrogen applications is becoming ever more important. The smallest molecule in the periodic table, hydrogen (H2) is around 14 times less dense than air. It is also colorless and odorless, which makes leakage hard to detect. This presents a safety problem, as escaping hydrogen poses a risk of explosion due to the formation of oxyhydrogen gas when in contact with oxygen. It also increases a system’s operating costs. With energy prices rising unabated, efficient leakage management is vital to minimize financial losses.
The challenges posed by flange connections
Flange gasket materials always contain air pockets. These are necessary to allow the fitted gasket to adapt to the texture and unevenness of the flange surface. As the flange bolts are tightened, the flange faces compress the gasket, with the possible compression depending on such factors as the flange materials, the bolts used and the gasket itself. In practice, the required leakage class can often not be achieved as the possible compression force is too low.
To address this problem, KLINGER A. W. Schultze has developed the Waveline WLP process. This works by pre-compressing gasket materials during their manufacture in such a way as to greatly reduce the volume of entrapped air they contain. This gives the gasket a wavy cross-section. Once installed, pre-compressed gaskets need a much lower compression force to achieve the same, or even a higher leakage class than conventional gaskets. The waviness ensures that the gasket can adapt to the flange.
A versatile sealing solution for hydrogen applications, the Egraflex Steelflon Waveline WLP consists of three main components:
Graphite: The material’s high purity of 99.85 percent ensures reliable sealing and consistent dimensional stability.
Stainless steel foils: The pre-compressed stainless steel inner flange increases the gasket’s mechanical stability and seals off its cross-section without the flange having to perform any major deformation work.
PTFE coating: A PTFE coating on both sides makes for very low leakage. It also stops the gasket adhering to the flange, so that no residue remains when removing it for replacement. This saves time and money during installation.
The combination of these materials makes the Egraflex Steelflon Waveline WLP a true all-rounder that cuts installation times and reduces leakage losses.
The Egraflex Steelflon Waveline WLP
Fact Box
Case example: H2 savings potential
To illustrate the cost savings that can be achieved with an optimized gasket in a common hydrogen application, let’s take a look at a DN40 PN40 flange system. A conventional DIN 1514 compliant fiber gasket subjected to a compression force of 30 MPa serves as our reference product. According to Gasketdata, this has a measured leakage rate for helium of 0.008 mg/(s·m). In terms of molecular weight, this corresponds to around 600 litersof hydrogen loss per year.
Assuming the price of hydrogen at around €1.00 per liter, this means that around €600 worth of hydrogen is lost every year through this single flange connection alone.
When the Egraflex Steelflon Waveline WLP was tested under the same conditions on an AMTEC test stand, the recorded leakage rate was a mere 0.000008 mg/(s·m). This corresponds to 0.12 liters of hydrogen lost per year at a cost of only around €1.10. In other words, a single DN40 PN40 flange connection would save nearly 600 liters of hydrogen per year, cutting operating costs by around €600 per year for every single flange within the system.
Note: These leakage figures are based on data from Gasketdata, which is also used in DIN EN 1591 to verify the tightness and strength of flange connections. These verifications are an essential part of the technical documentation, especially in cases where hazardous atmospheres can occur, such as in hydrogen applications.
The values calculated in accordance with DIN EN 1591 clearly demonstrate whether any specific gasket provides the required safety and efficiency under real-life operating conditions.
The Egraflex Steelflon Waveline WLP demonstrates how effectively advanced pre-compression and a modern gasket material can be employed to achieve a superior tightness – and therefore safety – in H2 applications. Their integrated stainless-steel elements and PTFE coating allow the gaskets to be changed quickly and without leaving any residue. The example calculations illustrate the tremendous savings potential of reducing hydrogen leakage and the ever-increasing importance of leakage testing in accordance with recognized standards such as DIN EN 13555.
Especially in hydrogen-conducting systems, where safety is paramount, it therefore pays to use state-of-the-art sealing systems that deliver convincing results even at a lower gasket compression.
The data given is correct to the best of our knowledge, but without guarantee of accuracy or completeness.