Flange Gasket

Why Choose Us?

Rich Experience

SJK was founded in 1994, focusing on the R & D, production, and sales of special rubber seals, and mastering high-end sealing professional production technology.

High Standard Products

The company mainly produces O-ring, ED ring, rubber gasket, rubber strip, and other sealing products.

Complete Qualifications

The enterprise has obtained IATF16949 certification, and has professional experimental facilities, more than 100 sets of advanced production and testing equipment, modern ERP management system, etc.

One-stop Service

In production, SJK has rich experience in seal mold development, and can undertake the design and manufacture of special and complex seals to meet customized needs of customers for special products.

Definition of Flange Gasket

Flange gaskets are designed to seal the space between two sections of pipe. Most pipes, of course, are joined at a flanged surface. The surface where two pipes join isn't smooth or otherwise flat. Rather, it's flanged, meaning it flares out. For flanged surfaces such as this, flange gaskets are used.

There are mainly two kinds of flange gasket, one is RF and the other one is FF. Both of them are flat gasket. Besides, custom made size and structure is support in Jiacheng New Material (SJK).
EPDM and FKM are the most common material request of flange gasket. Besides, SJK can produce in NR, NBR, HNBR, etc.
Contact us to choose the right one for your working condition.

Benefits of using Flange Gasket

Ensuring leak-free operations
Flange gaskets serve as a critical seal between pipe sections. Without them, the risk of hazardous leaks increases significantly. Consequently, selecting high-quality gaskets is crucial for any industry relying on fluid systems.

Material matters
Different applications require different gasket materials. For instance, rubber gaskets may be perfect for water systems. However, for oil or chemical applications, neoprene or teflon might be better choices. Thus, understanding the specific needs of your system is key.

Cost-effectiveness
Using flange gaskets can also be extremely cost-effective. Although they may seem like a small part of your budget, they prevent expensive repairs and downtime. Therefore, investing in good quality gaskets pays off in the long run.

Safety and compliance
Additionally, flange gaskets are vital for safety and compliance with industry standards. Ineffective sealing can lead to leaks that may cause environmental damage or endanger workers. Hence, compliance with safety standards is non-negotiable.

Longevity and durability
A durable flange gasket extends the lifespan of piping systems. It withstands various pressures and temperatures, reducing the need for frequent replacements. Hence, durability translates to fewer interruptions and sustained productivity.

What Are the Common Types of Flange Gaskets?

Gaskets are sealing elements installed between mating flange faces. The compressive force applied when flanges are mated (due to bolt torqueing) keeps the gasket in position between the two flanges. Flange gaskets are split into three main categories.

Non-metallic / Soft – Compressed non-asbestos fibre (CNAF), PTFE, rubber, ceramic fibre
Soft gaskets (non-metallic gaskets) have a large contact sealing area and are suitable for low pressure applications only. The usage of soft gaskets is mostly restricted to flat face flanges, although it is possible to use them with raised face flanges also. Irrespective of the type of flange used, a soft gasket should be installed on a serrated flange surface to avoid poor sealing. The general appearance of most soft gaskets is that they are thin and malleable (can be bent by hand); they are often delivered in rolls and have to be unwound before use.

Metallic / Hard – oval ring, octagonal ring
Hard gaskets (metallic gaskets) have a small contact sealing area and are used for medium to high pressure applications. Because metallic gaskets are 'hard' , they must have a small sealing face in order to achieve the pressure required to deform the gasket and obtain a reliable seal. The most common type of metallic gasket is the ring-type joint, although others exist e.g. lens ring.

Semi-metallic / Composite – spiral wound, metal jacketed, camprofile
Composite gaskets consist of two or more materials. The soft material is placed between the sealing faces of a flange to create the required seal. The hard material gives the gasket greater rigidity and sturdiness, which helps the softer material resist deformation effects such as squeezing, buckling, and blow-out. Composite gaskets are used across a wide range of pressures and temperatures and are thus available in all pressure classes.
Composite gaskets can be split into three main categories, these are the spiral wound, metal jacketed and camprofile. Of these three, the spiral wound type is by far the most common. A composite gasket may be used with a raised face flange, tongue-and-groove flange, or a male-and-female flange.

Flange Gaskets: Full-Face or Ring

When sealing raised or flat face flanges there are two choices of gasket shape: full-face gasket and ring-type. Each has advantages, so before ordering you should know which will suit your application best. You should also understand the measurements your gasket supplier needs before cutting material. ASME standards describe several designs, but the most common are the raised face and the flat face. The difference between them is that the raised face flange has a raised region surrounding the pipe bore. The bolt holes are outside of this. The flat face flange has no such step.

● The Ring-Type Gasket
This is positioned inside of the flange bolts and around the pipe bore. In a raised face design it sits on that surface. This design:
Requires less material and less cutting.
Can be installed without completely dissembling the joint, (making it a "drop in" gasket.)
Is harder to clamp in position.
When specifying a ring type gasket only three measurements are needed: ID (which corresponds to the pipe bore,) OD (which is the same is the OD of the raised face,) and gasket thickness.

● The Full-Face Gasket
Like the ring-type gasket, this seals on raised flange faces, but has an OD the same as the flange. That means it needs holes for the securing bolts to pass through, and these help locate it on the flange, making alignment easier. Extending out to the flange OD has the added benefit of filling the gap between bolting surfaces, which stops dirt getting in. However, the joint must be completely dissembled for installation.
Specifying a full-face gasket requires these measurements:
ID (same as the pipe bore.)
OD (same as the flange OD.)
Bolt circle diameter (the diameter on which all the bolt hole centers are located.)
Number of bolt holes (and spacing if they're not be regular – which would be very unusual.)
Gasket thickness.

Selection Criteria for the Perfect Flange Gasket

Selecting the right flange gasket is crucial for the safety and efficiency of industrial systems. There are several factors that need to be considered when selecting a flange gasket to ensure that it is the best fit for the requirements of the application.

Material selection and chemical resistance

Materials: The choice of the right material depends on the type of liquids or gases that are transported in the pipelines. For example, corrosive chemicals require a seal with high chemical resistance, such as PTFE.
Chemical resistance: The seal must be resistant to the specific chemicals with which it comes into contact in order to prevent corrosion and material degradation.

Temperature and pressure resistance

Temperature range: The seal must be suitable for the operating temperature range of the application. High-temperature applications, for example, require metallic or special high-temperature seals.
Pressure range: The maximum pressure load to which the seal is exposed determines the choice of seal type. High-pressure applications require more robust, often metallic seals.

Flange type and size

Flange compatibility: The gasket must exactly match the flange type and its size. This includes consideration of the flange geometry, bolt distribution and gasket fit.
Sizing: Correct sizing is essential for sealing efficiency. A seal that is too large or too small can lead to leaks.

Checklist for the selection

Determine the chemical compatibility: Make sure that the sealing material is compatible with the transported media.
Determine the required temperature and pressure range: Select a seal that can withstand the operating conditions.
Check the flange specifications: Ensure the exact fit and size for your specific flange.
Take the ambient conditions into account: Ensure that the seal remains functional even under the prevailing ambient conditions.

How Flange Gaskets Work?

Flange gaskets work in the same way as most other gaskets. When installed, they create a sealed mating surface so that water or other liquids won't leak out. Pipes typically have water or liquids flowing through them. If two pipes are joined together, the water or liquids may leak out through this mating surface. Flange gaskets prevent this from happening by sealing the surface.

Pipes generally don't offer a sealed mating surface when used alone. This is especially true in the case of pipes with a flanged surface. Since flanged surfaces are flared, water and liquids can easily escape through the cracks. A simple solution to prevent leaks is to install a flanged gasket. The flanked gasket will contour to the shape of the pipes' flanged surface so that water or liquids stay within the pipes.

Different Flange Gasket Types and Their Usage in Various Applications

Full-face gasket
Covers the entire face of the flange.
It consists of bolt holes matching the flange.

Ring-type gasket
The intended use is to fit inside the bolt circle of a flange.
Metals like stainless steel or carbon steel are used to make these gaskets.

Spiral wound gasket
It comprises metal winding with filler materials like graphite placed between the windings.
Suitable for high-pressure and high-temperature applications.

Kamm profile gasket
It consists of a serrated metal core with a soft material, such as graphite or PTFE, placed on either side.
Used in high-temperature and high-pressure applications.

Jacketed gasket
It has a metal casing around a soft filler material like graphite or PTFE.
They are common in heat exchangers and other applications with high temperatures and pressures.

Corrugated metal gasket
Made of a thin metal sheet corrugated or folded to create a seal.
Used in high-pressure and high-temperature applications.

Rubber gasket
For rubber gaskets, they use elastomeric materials and rubber.
Used in low-pressure applications.

Our Factory

Zhejiang Jiacheng New Material Co.,Ltd. (SJK for short) was founded in 1994, focusing on the R & D, production, and sales of special rubber seals, and mastering high-end sealing professional production technology. The company mainly produces O-ring, ED ring, rubber gasket, rubber strip, and other sealing products.

As a leading enterprise in domestic fluorine material sealing industry, SJK always keeps in mind the enterprise mission of "Striving for maximum interests of enterprises and customers". At present, SJK has won the trust and recognition of many well-know customers at home and abroad, and its sales network has covered Europe, America, the Middle East, Southeast Asia, and other places. With the vision of "becoming a world famous seal brand", SJK keeps forging ahead, has the courage to shoulder social responsibility, and abides by the core values of "honesty, pragmatism, innovation, and win-win". Strive to build the first brand of high-end seals.

Video 1

Video 2

Video 3

Our Certificate

Ultimate FAQ Guide to Flange Gasket

Q: What is the purpose of a flange gasket?

Q: Do I need a flange gasket?

A: Why you may need a flange ring. There is internal pressure (such as combustion pressure) that needs to be contained. The gasket material needs to be protected from the internal fluid or pressure or high-temp exposure that might degrade it over time.

Q: How long do flange gaskets last?

A: A gasket may last 5 years, or it could last 20 years. I cannot give you an exact date or lifespan of a gasket; however I can give you some insight into factors that will give your gasket the best chance at a long and prosperous life between the flanges.

Q: Why do flanges need flange gaskets?

A: If two pipes are joined together, the water or liquids may leak out through this mating surface. Flange gaskets prevent this from happening by sealing the surface. Pipes generally don't offer a sealed mating surface when used alone. This is especially true in the case of pipes with a flanged surface.

Q: Can flange gaskets be reused?

A: We are frequently asked about reusing gaskets. We do not recommend this practice. A gasket's function is to conform to flange high and low spots when compressed, and its ability to reseal decreases after it is compressed.

Q: How do you size a flange gasket?

A: Measuring flange gaskets. This can be measured with a tape measure from the inside of one hole to the outside of the other (as per the image above), providing the hole diameters are equal. It would also be useful to make note of the gasket thickness to ensure you know the complete dimensions required.

Q: Why are gaskets placed between two flanges?

A: Flange gaskets are mechanical seals; placed between two flanges to prevent liquid or gas leakage. Such gaskets can be made of diverse materials like rubber, cork, fiber, or metal and are available in various shapes and sizes.

Q: Is flange gasket often encountered?

A: A flange gasket is a common type of gasket, which is used frequently in pipes and pipework. A flange gasket is designed specifically for flanged surfaces, which fan out, rather than being smooth or flat. The primary aim is to seal the space between two surfaces on a pipe to reduce the risk of leaks into and out of the pipe.

Q: What are the types of flange gaskets?

A: In piping systems a flange gasket is placed between two connecting flanges to create a leak proof seal. The three primary types of flange gaskets are non-metallic, semi metallic and metal gaskets. The non-metallic flange gaskets are used in low pressure, low temperature and noncritical service applications. The semi metallic flange gaskets are a combination of metal and nonmetal materials based on product and service requirements. The metal flange gasket is all metal flange gasket made from carbon steel, stainless steel or other exotic alloy.

Q: How does a flange gasket work?

A: Flange gaskets work in a similar way to other types of pipe gaskets, but they are specifically designed to seal sections that have flanged surfaces. Pipes usually carry liquid, which could leak out of a pipe that is not secured. Pipe gaskets are used to create a seal, which prevents this from happening. Flanged surfaces are particularly high-risk when it comes to leakages due to the presence of cracks in the pipework. With a flange gasket, the seal moulds to the contours of the pipe sections, forming a barrier to keep liquids within the pipe.

Q: What are flange gaskets used for?

A: The most common use of pipe gaskets is to prevent leakages from pipes used in the oil and gas industry and other industrial applications. Pipe gaskets provide a seal, which joins two sections of pipework together at a flanged surface. With a strong seal in place, the risk of liquid or gas seeping out of the pipes falls dramatically. Gaskets can also be used to seal water and oil tanks, to provide a seal for fuel tank boilers and to aid mounting.

Q: What are the advantages of flange gaskets?

A: Flange gasket connections are easy to assemble and provide the best option in larger diameter applications, especially when under high pressure. They provide significant advantages versus threaded fittings in these larger, more severe applications, such as: Easier to assemble in tight spaces.

Q: What is the purpose of a flange gasket?

A: Flange gaskets are used to connect pipes with each other, to valves, to fittings, and to specialty items such as strainers and pressure vessels. A cover plate can be connected to create a "blind flange". Flanges are joined by bolting, and sealing is often completed with the use of gaskets or other methods.

Q: How to choose a flange gasket?

A: The gap between the flange gaskets, when placed together empty, must be measured before the gasket is ordered. Gasket thickness should be four to five times the maximum gap observed. Stainless steel (ss) flanges are common in many plants for chemical service, and often utilize low strength ss bolts.

Q: How do I know what size flange gasket I need?

A: First, measure the inside dimension (i.D.) and outside dimension (o.D.) just like you would a ring gasket. Then, count the number of bolt holes and also measure the diameter of the bolt holes. The final dimension is the bolt circle.

Q: How to choose a flange gasket?

A: Some factors that buyers should consider as they purchase gaskets include:
The amount of force the two surfaces will exude on the gasket.
The degree of surface unevenness (which dictates how thick the gasket should be)
The fluids and any ambient contaminants.
The compressibility of the gasket material.

Q: How should flange gaskets be stored?

A: Store in a cool, dry area and minimize dust exposure. Keep gaskets out of the elements. Avoid leaving gaskets out in the rain or on the ground where they can collect unwanted debris, or even pesticides.. Storage of gaskets in freezing conditions is not recommended.

Q: How do you size a flange gasket?

A: Measuring Flange Gaskets. This can be measured with a tape measure from the inside of one hole to the outside of the other (as per the image above), providing the hole diameters are equal. It would also be useful to make note of the gasket thickness to ensure you know the complete dimensions required.

Q: Should you lubricate flange gaskets?

A: When a flange gasket is reused, it will be unable to recover up to 100% of the original thickness and the recovery of the gasket will drastically decrease each time it is compressed. It is important to always use lubrication during installation.

Q: How do you cut a flange gasket?

A: The material can be cut with a utility knife, scissors or shears, or even by a battery operated device. The dimensional tolerance of hand cut gaskets is based on the person cutting the gaskets, however, realistically the tolerance on most hand cut gaskets would be greater than +/- 3.2mm (1/8").

Q: How thick is a flange gasket?

A: For this reason, as a general rule: the thinner the gasket the better. Common thicknesses of gasket material for pipe flanges are 1.5mm and 3mm.