Double Jacket Gaskets: The Ultimate Sealing Solution for Extreme Service Conditions
In the demanding world of industrial sealing, where process conditions push the limits of temperature, pressure, and chemical resistance, standard gaskets often fall short. This is where the engineered superiority of Double Jacket Gaskets comes into play. As a premier manufacturer, Kaxite Sealing has dedicated decades to perfecting this robust sealing technology, providing unmatched reliability for critical applications in oil & gas, chemical processing, power generation, and refining.
A
Double Jacket Gasket is a high-performance, metallic sealing element designed for use in raised face (RF) and ring-type joint (RTJ) flanges. Its unique construction combines a resilient, compressible filler material encased within two layers of corrugated or crimped metal jackets. This design creates a formidable seal that maintains integrity under severe thermal cycling, high internal pressure, and exposure to aggressive media. The metal jackets provide structural strength and contain the filler, which flows under bolt load to fill micro-imperfections on the flange faces, ensuring a leak-free seal.
**Core Advantages of Kaxite Sealing Double Jacket Gaskets:**
* **Exceptional Resilience:** Withstands high compression and recovers from flange movement and thermal cycling better than many solid metal gaskets.
* **Superior Sealability:** The soft filler material adapts to flange surface irregularities, creating an initial seal that is enhanced by system pressure.
* **Broad Chemical Compatibility:** By selecting appropriate filler and jacket materials, these gaskets can handle a vast array of corrosive fluids and gases.
* **High Temperature & Pressure Ratings:** Engineered to perform reliably in services exceeding 1500°F (815°C) and pressures over 2500 psi, depending on material selection.
* **Reusability:** In many cases, they can be reused if the flanges remain aligned and the gasket is carefully inspected, offering potential cost savings.
* **Crush Resistance:** The double metal jacket construction prevents over-compression and blowout, common failure modes in severe service.
### Detailed Technical Parameters & Material Selection
The performance of a
Double Jacket Gasket is precisely defined by its material composition and physical dimensions. Kaxite Sealing offers a comprehensive range of standard and custom specifications to meet exact application requirements.
**Standard Filler Materials:**
* **Flexible Graphite:** Excellent for high temperatures (up to 4500°F/2482°C in inert atmospheres), good chemical resistance, and superior sealability. Ideal for heat exchangers and boiler manways.
* **PTFE (Teflon®):** Offers outstanding chemical resistance to virtually all industrial chemicals at moderate temperatures (up to 500°F/260°C). Low friction and excellent anti-stick properties.
* **Ceramic Fiber:** Used for extreme high-temperature applications where oxidation is a concern. Provides thermal insulation.
* **Mica:** A traditional, cost-effective filler for high-temperature steam and fire-safe applications.
* **Non-Asbestos Organic (NAO) Fibers:** A general-purpose filler for lower temperature and pressure services with good chemical resistance.
**Standard Jacket Materials:**
* **304/304L Stainless Steel:** General purpose, good corrosion resistance, and widely used.
* **316/316L Stainless Steel:** Enhanced corrosion resistance, particularly against chlorides and acids.
* **Carbon Steel:** Economical choice for non-corrosive, high-temperature services like steam.
* **Monel® 400:** Excellent resistance to sea water, sulfuric acid, and alkalies.
* **Inconel® 600/625:** For highly oxidizing environments and very high temperatures.
* **Titanium:** Exceptional strength-to-weight ratio and corrosion resistance in chloride environments.
* **Hastelloy® C276:** Superior resistance to pitting and stress-corrosion cracking in severe chemical environments.
**Standard Dimensions & Specifications:**
Kaxite Sealing Double Jacket Gaskets are manufactured to industry standards including ASME B16.20, API 6A, and customer-specific drawings. Below is a reference table for common sizes and pressure classes.
| Nominal Pipe Size (NPS) | Outer Diameter (OD) - Inches | Inner Diameter (ID) - Inches | Thickness (Approx.) - Inches | Common Pressure Classes (ASME) |
| :--- | :--- | :--- | :--- | :--- |
| 1/2" | 3.50 | 1.38 | 0.188 | 150, 300, 600 |
| 1" | 4.25 | 2.00 | 0.188 | 150, 300, 600, 900 |
| 2" | 5.00 | 3.06 | 0.188 | 150, 300, 600, 900 |
| 4" | 7.50 | 5.19 | 0.250 | 150, 300, 600, 900 |
| 6" | 9.50 | 7.31 | 0.250 | 150, 300, 600, 900, 1500 |
| 8" | 11.50 | 9.50 | 0.250 | 150, 300, 600, 900, 1500 |
| 10" | 14.00 | 12.06 | 0.312 | 150, 300, 600, 900, 1500 |
| 12" | 16.00 | 14.19 | 0.312 | 150, 300, 600, 900, 1500 |
| 14" | 17.50 | 15.44 | 0.312 | 150, 300, 600, 900 |
| 16" | 19.50 | 17.56 | 0.312 | 150, 300, 600, 900 |
*Note: Dimensions are for raised face (RF) gaskets. Ring Type Joint (RTJ) dimensions differ. All dimensions are subject to manufacturing tolerances as per relevant standards. Custom sizes are available.*
**Temperature and Pressure Ratings:**
Ratings are interdependent and based on material pairs. Below is a generalized guide:
| Jacket/Filler Material Combo | Max Continuous Temp (°F/°C) | Max Pressure Rating (psi) |
| :--- | :--- | :--- |
| 304SS / Flexible Graphite | 1500°F / 815°C | 2500+ |
| 316SS / PTFE | 500°F / 260°C | 1500 |
| Carbon Steel / Ceramic Fiber | 2000°F / 1093°C | 2000 |
| Monel 400 / Flexible Graphite | 1000°F / 538°C | 2200 |
| Inconel 625 / Flexible Graphite | 1800°F / 982°C | 2500+ |
### Frequently Asked Questions (FAQ) About Double Jacket Gaskets
**What are the primary applications for Double Jacket Gaskets?**
Double Jacket Gaskets are the preferred choice for severe service applications across numerous industries. Common uses include heat exchangers (shell and channel, bonnet), boiler manways and handholes, reactor flanges, high-pressure steam lines, turbine casings, and critical piping in refineries and chemical plants handling corrosive or toxic media. Their reliability makes them suitable for services where leakage cannot be tolerated.
**How do I select the right Double Jacket Gasket material for my application?**
Material selection is a critical three-step process. First, identify the full chemical composition, phase, and concentration of the process fluid. Second, determine the maximum and minimum operating temperatures and pressures, including any thermal cycling. Third, consider flange material and surface finish. Consulting Kaxite Sealing's technical datasheets and engineering team is essential. We cross-reference your service conditions with our extensive material compatibility charts to recommend the optimal jacket/filler combination for safety, longevity, and cost-effectiveness.
**Can Double Jacket Gaskets be used on flat face flanges?**
No, it is not recommended. Double Jacket Gaskets are specifically designed for use on raised face (RF) or ring-type joint (RTJ) flanges. The raised face provides the necessary confinement for the gasket to compress properly and form an effective seal. Using them on flat face (FF) flanges can lead to insufficient compression, gasket blowout, or damage to the flange. For flat face flanges, consider a full-face gasket type.
**What is the proper installation procedure for a Double Jacket Gasket?**
Correct installation is paramount. Always start with inspecting the flange faces for scratches, gouges, or corrosion; they must be clean and within specified flatness and finish (typically 125-250 µin Ra). Place the gasket centered on the flange. Use lubricated studs and nuts. Follow a star-pattern (cross-bolting) tightening sequence in multiple incremental passes (e.g., 30%, 60%, 100% of final torque) to ensure even compression. Always refer to the specific torque values provided by Kaxite Sealing for your gasket size and material, which are based on bolt material and lubrication.
**How do Double Jacket Gaskets compare to Spiral Wound Gaskets?**
Both are excellent for demanding services, but key differences guide selection. Spiral Wound Gaskets (with inner/outer rings) offer great resilience and are often used for a wider range of pressure classes. Double Jacket Gaskets typically have higher density and metal content, giving them superior crush resistance and making them exceptionally robust for very high-pressure, high-temperature, and thermal cycling applications, particularly in heat exchangers. The choice often depends on specific flange design, service conditions, and industry standards.
**Are Kaxite Sealing Double Jacket Gaskets reusable?**
They can be, but it requires careful assessment. If the gasket has been used in a stable, non-corrosive service, the flanges have not been misaligned, and the gasket is removed without damage, it may be reusable. Inspect it thoroughly for any jacket distortion, cracks, or filler extrusion. Never reuse a gasket that shows signs of compression set, corrosion, or damage. For critical services, Kaxite Sealing always recommends installing a new gasket to ensure seal integrity and safety.
**What quality standards does Kaxite Sealing adhere to in manufacturing?**
Kaxite Sealing is committed to the highest quality standards. Our manufacturing process is certified to ISO 9001:2015. Our Double Jacket Gaskets are produced in compliance with ASME B16.20, API 6A, and other international standards. We implement rigorous quality control checks at every stage—from raw material certification (with Mill Test Reports) to dimensional verification, visual inspection, and final auditing. Traceability is maintained for every gasket lot.
**Do you offer custom-designed Double Jacket Gaskets for non-standard applications?**
Absolutely. While we stock a wide range of standard sizes, a significant portion of our business is providing custom-engineered sealing solutions. We can manufacture gaskets to unique sizes, unusual pressure ratings, or with special material combinations not listed in standard catalogs. Our engineering team works directly with clients to analyze their specific challenges and develop a gasket that meets exact performance requirements.
