Resilient Seated vs Metal Seated Gate Valves: Key Differences

July 26, 2024
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Gate Valve: A gate valve is a type of valve where the closing element (gate) moves in a vertical direction along the centerline of the passage. Gate valves can only be used for fully open or fully closed cut-off in pipelines, they cannot be used for regulation or throttling.

Gate valves are classified into Resilient sealing gate valves and metal sealing gate valves based on their sealing structures. In this article, I will explain the characteristics of resilient seated gate valves and their differences from metal sealing gate valves. I hope this will help you gain more insight into the practical applications of resilient sealing gate valves and determine which type of gate valve is more suitable for your needs.

Resilient sealing gate valves and metal sealing gate valves are two main categories within the gate valve series, featuring different sealing structures. Both types operate on the same principle and are used to cut off fluid flow. Metal sealing and resilient sealing can sometimes complement each other, while at other times, they function independently.

What Is Resilient Seated Gate Valve

A resilient seated gate valve uses a rubber-covered gate, typically EPDM or NBR, to achieve tight shut-off. The valve body is commonly made of ductile iron and coated with epoxy for corrosion protection.

This design is widely used in water supply, irrigation, HVAC, and municipal pipelines because it provides low operating torque, reliable sealing, and relatively simple maintenance.

Main Features of Resilient Seated Gate Valve

1. Reliable Sealing

The rubber-covered gate provides tight contact with the sealing surface and can achieve zero leakage when designed and tested to the applicable leakage class. This makes resilient seated gate valves suitable for water supply and other applications requiring reliable shut-off.

2. Low Operating Torque

The resilient sealing structure reduces friction during opening and closing, helping to lower operating torque and making the valve easier to operate manually or with an actuator.

3. Corrosion Protection

The valve body is commonly made of ductile iron with an epoxy coating to improve corrosion resistance. EPDM or NBR is typically used for the rubber-covered gate, depending on the medium and operating conditions.

4. Easier Maintenance

Some designs allow stem seals to be replaced without removing the valve from the pipeline, but this depends on the specific valve construction. Maintenance requirements should always be confirmed according to the valve design and manufacturer instructions.

5. Different Sealing Designs

Parallel and wedge sealing designs are both used, depending on valve size, manufacturer design, and application requirements. The appropriate structure should be selected according to pressure, pipeline conditions, and operating requirements.

6. Common Applications

Resilient seated gate valves are widely used in water supply, irrigation, HVAC, fire protection, and municipal pipeline systems where reliable sealing, corrosion resistance, and relatively low operating torque are required.

The Difference Between Resilient Gate Valve And Metal-Sealing Gate Valve

Let’s take a look at the differences between resilient seated gate valve and metal sealing gate valves:

1.Resilient Seated Gate Valve:The gate is lined with resilient rubber, and the internal structure is wedge-shaped. When the handwheel mechanism at the top is turned, the spindle lowers, pressing the resilient gate against the internal wedge groove, creating a tight seal due to the rubber's ability to compress and expand. The design of resilient sealing gate valves is straightforward, making them easy to disassemble and install. Maintenance is typically simple, requiring only the replacement of the gate, making it convenient to repair.

Metal Sealing Gate Valves:The sealing surfaces of the valve body and gate are made from the same material, such as copper alloy or stainless steel. When these surfaces wear out, both the valve body and gate require simultaneous maintenance, which is more complex.

2.Resilient Seated Gate Valves: The valve body is designed without grooves, which prevents the accumulation of impurities.

Metal Sealing Gate Valves: Due to the sealing surfaces on both sides of the valve body, there are grooves at the bottom of the valve body. Over time, impurities can accumulate in these grooves, blocking the gate's descent and causing sealing failure.

3.Resilient Seated Gate Valves:The valve body is coated with epoxy resin, which is corrosion-resistant and non-polluting, making it suitable for use in drinking water pipelines.

Metal Sealing Gate Valves: These typically use paint for coating, which can slightly pollute water. However, modern hard sealing gate valves for drinking water pipelines also use epoxy resin coating.

4.Resilient Seated Gate Valves:The valve cover uses hexagon socket screws, which are sealed with wax after tightening to prevent rust between the screws and the valve body, facilitating future disassembly and maintenance.

Metal Sealing Gate Valves: These usually use hexagon bolts, but some models also employ a similar hexagon socket screw structure.

5.Applicable Medium Temperature Differences:

Resilient Seated Gate Valves: The sealing material has limited temperature resistance, making it suitable for low-temperature environments. It tends to fail under high temperatures and has poor wear resistance, making it less suitable for mediums containing solid particles. It also has a relatively narrow pressure range, potentially affecting sealing performance in high-pressure environments.

Metal Sealing Gate Valves: The sealing material is usually metal, such as stainless steel or hard alloys, which are suitable for high-temperature and high-pressure conditions, maintaining good sealing performance and stability. The metal sealing surface is wear-resistant, enduring medium erosion and wear, thus offering a longer service life. These valves are suitable for mediums with solid particles or strong corrosiveness

How to Choose Between Resilient Seated and Metal Seated Gate Valves

Choose a resilient seated gate valve when tight shut-off, corrosion resistance, low operating torque, and clean water service are the main priorities. These valves are commonly used in water supply, irrigation, HVAC, and municipal pipeline systems.

Choose a metal seated gate valve when the application involves higher temperature, higher pressure, abrasive media, or more demanding industrial conditions where greater wear resistance is required.

The final selection should always consider the medium, temperature, pressure, installation conditions, maintenance requirements, and applicable valve standards.

Union Valve can help confirm the appropriate gate valve type, materials, pressure rating, and standards based on your project requirements. For more information, please contact us as soon as possible.