EGR (exhaust gas recirculation) valves serve a specific purpose in engines. They recirculate exhaust gases from the exhaust stream, sending some back into the engine to be burned again. This helps to reduce emissions by further burning the byproducts of combustion.
EGR valves can be thermally operated or electrically operated. Generally, there is an operating mechanism that “opens” and an actuator mechanism that makes it do so. Older style EGR’s had more mechanical operation driven by heat to open the valve. More recent styles feature electrically operated valves.
What Material Should You Use?
If you are involved with making the decision on EGR gasket material, there are 3 main items of consideration.
1. Temperature Involved
EGR by nature is a hot application. Designers need to know the temperature exposure that an EGR seal point would see to determine what material to use. Generally, a metal-reinforced material is the proper solution. With high temps (>1000°F), a mechanically clinched product is best. Over the years, flexible graphite has been an excellent solution in this area. High-temp fiber products have also shown good performance and offer insulative properties as well.
2. Flange Load
Generally, an EGR valve flange features stiff flanges and 2 sufficient bolts. This is usually adequate for a tanged metal composite gasket (either graphite or high-temp facing) to seal both initially and long term. For joints where less flange load is available and temperatures are not as high, a solid core graphite design might be considered.
3. Insulate or Conduct
The thermal question is key. With the exposure to high temperature always present, the control part of the valve needs to be protected or isolated from the heat. In many cases, designers prefer an insulative material to accomplish that task.
Decide on a Material
EGR valve gasket applications are an excellent candidate for metal-reinforced, high-temperature gasket material.
If you have any questions about your EGR application, please let us know! If you are interested in subscribing to Sealed-In’s blog posts, email firstname.lastname@example.org.
Metal Tech manufactures HT 400 and has had much success with it over the years in EGR valve gasket applications. The HT 400 offers thermally insulative properties to reduce heat flow and protect the components while maintaining an effective seal.
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Gasket materials that have insulative properties can be a perfect fit for your application in so many ways. Keep reading for a list of considerations if you are trying to decide if this would be the answer to your problem.
Are Surface Finishes Important When Working With Composites?
In many of today’s newer applications, the surface finish of the flange is almost always something that must be addressed due to the popularity of selecting SLS (single layer steel) and MLS (multi-layer steel) gaskets for applications. However, it is important to know that there are other solutions that do not require the expensive machining for the flanges, and they work well in the aftermarket (where the stainless steel shims typically do not). Have we caught your interest? Keep on reading for more.
Why Would I Use Composite Gasket Material When I Can Use MLS?
Whether you are someone that has been a fan of MLS for awhile, or someone who has been a loyal fan of composite but just needs a reminder about why you’ve stuck with it for so long, here are the reasons you should (or still should) consider composite material the next time you need gasket material.
The Top 6 Applications Where Composite Gaskets Excel
As an experienced materials manufacturer, when we hear a customer or potential customer start talking about gasketing needs, there are certain applications where we know immediately that metal-reinforced composite laminates are a great option. To help you in your planning process, we decided to put together a list of the top applications where these types of gaskets excel (in no particular order).
The Metal Tech Hi-Tex series features our specially designed starburst core tang technology. This robust metal core, available in carbon or stainless steel, provides optimum strength for the laminate in the most demanding applications.