Improving sealing performance in heat exchanger applications requires taking a closer look at long-standing industry assumptions.
At 3S-Superior Sealing Service (3S), this approach is central to modernizing gasket technical expertise. Our engineering department regularly tests gaskets to confirm the gaskets meet or exceed industry quality standards. Those findings, which often challenge old data, are published and presented to support our customers and the industry at large.
Recently, a customer questioned the efficiency and integrity of a traditional gasket used on a new heat exchanger which prompted us to study the gasket’s performance. Our study confirmed that the old "industry standard" wasn’t the right gasket for our customers’ application.
Our new study and engineering efforts have focused on improving the sealing performance of pass bar rib gasket designs used in heat exchanger applications that can now be used industry wide to improve gasket performance. The pass bar rib study researches the sealing performance of different pass bar rib gasket styles used on heat exchanger applications where pass partition plates are utilized to separate two or more substances. Pass bar rib gaskets are typically situated within machined grooves on the channel-to-tube sheet joint, channel cover flange or channel floating head. We tested 10 different styles of gaskets for leakage rates and pressure drop values.
Higher demands are being placed on plant equipment. Therefore, the safety, efficiency and emissions of these units must be to the highest possible standard. When a leak occurs on the main seal of a flange, this leak is often apparent to the operator. Conversely, due to the seal being enclosed inside the heat exchanger body, this type of leak is not apparent, which can greatly reduce the efficiency and output of the heat exchanger process and ultimately affect the quality of the final product.
There is currently limited leakage test data available for the different styles of pass bar rib gasket combinations. Most common heat exchanger gasket designs are legacy and as such, may not be suitable for modern day process unit heat exchangers. This study provides gasket and heat exchanger manufacturers with a better understanding of the performance of the pass bar rib section of the gasket, in combination with the outer main seal allowing them to make more appropriate choice when purchasing a gasket.
There are many different combinations of gasket types and pass bar rib styles that are used in heat exchanger applications. We evaluate twelve different combinations of outer seal and pass bar rib gaskets, which are available as standard from 3S.
When two different gasket styles are used in a heat exchanger pass partition application, there are different compression rates, which can result in varying gasket stresses across the main sealing element and pass partition seal. Each gasket style also has different minimum sealing stress values, which can result in varying leakage rates on the same bolted flange joint.
Results from this project show leakage rates across the pass partition section of the gasket at different gasket stresses. Each test gasket replicates a heat exchanger design, circular main seal and a pass bar rib which is situated on the gasket’s inner diameter. Compression data is recorded for the main gasket seal and pass bar rib section throughout testing. This process provides a better understanding of the relationship between compression, gasket stress and resulting leakage.
The study provides engineers and end users with the data required to select the appropriate combination of pass bar rib and gasket style to achieve a safe and efficient bolted joint on heat exchanger flanges that have pass partition plates.
For more information, visit 3sgaskets.com/technical-expertise or email technical@3sgaskets.com.
