Parallel Slide Gate Valves: What Are Their Advantages?

In applications requiring high temperatures and pressures, including feed water and steam, parallel gate valves are frequently utilized. Better sealing performance is achieved by placing two discs in parallel with a compressed spring between them and double sealing with line pressure.

The Parallel Slide Gate Valve is a unique type of valve.

The conventional flexible wedge-shaped valves can be replaced with this option. The disc is made up of two halves that sit on parallel seat rings and are squeezed by a spring. As the name suggests, the disc "slides" as it comes into contact with the seats.

Without the aid of the wedge system, the horizontal spring between the discs and the seat rings ensures that they remain in constant contact and have a tight seal.

The parallel slide gate valve's sealing mechanism

It is the first seal of parallel gate valves under low pressure conditions, and the compressed spring will push the discs to the sealing rings when the pipe pressure or the pressure differential between two sides is modest.

The secondary seal is created when the pipeline pressure rises because the rising line pressure will drive the disc against the seat ring on the low pressure side. The sealing efficacy improves with increasing medium pressure.

As a result, high pressure and high temperature services like feed water and steam frequently use this kind of valve.

The parallel gate valve has the following benefits over the conventional gate valve type:

In contrast to a gate valve type that is closed while the pipe is at room temperature and open when the pipe is cold, the discs of a parallel gate valve will never seize up when the valve is closed.

A smaller actuator and less expensive actuator systems are the result of the parallel gate valve's significantly lower opening/closing torque compared to a similar gate valve type.

Dirt is kept away from the sealing surfaces by the "slide" feature.

Chemical, petroleum, natural gas, oil, and storage pipelines with high working temperatures, as well as pipelines with suspended particles, urban gas pipes, and hydraulic engineering, all make extensive use of parallel gate valves.

Benefits of Parallel Slide Gate Valves

Doesn't Need a Strong Torque to Turn Off

Because position seating is used, a significant torque or working force is not necessary for the valve to shut off. In order to provide a positive shut-off without leakage, the valve uses line pressure to hold the downstream disc against the downstream seat of the body. This is a significant advantage over the way a double-disc wedge is intended to operate. Because a double-disc wedge depends only on torque to push the wedge-shaped disc into the body seats, it quickly causes irreversible damage to the seat face and creates a leak path.

Lower Torque Needed

The parallel slide gate valve requires less torque, or operating force, to open and close since it is a position seating type valve and may seal using line pressure. This offers economic benefits by enabling the valve to be operated by smaller actuators.

Expanded Seating Area

A parallel slide gate valve's broad, flat sitting surface is advantageous because it keeps the seat from deforming, which could eventually cause leaks, saving you money on routine maintenance and repairs. By lessening wear, the large seating surface area also contributes to the seat's longer lifespan.

Due to their relatively thinner seating surface, wedge gate valves are susceptible to deformations.

Diminished Seat Wear

By distributing the bearing tension evenly over a greater area, the parallel gate valves' wide sitting surface also helps to lessen seat wear.

No Reseating of the Disc

The parallel slide gate valve's wide flat seat and seating design allow the discs to stay in their original position even after the valve has attained operating temperature, which is a major benefit. This also holds true when the valve cools down after being subjected to high temperatures.

However, wedge gate valves are not the same. The valve's design may necessitate reseating it once it has reached operational temperature in order to achieve a tight seal because of the body's thermal expansion.

Wedge gate valves can also experience "thermal locking," which occurs when a closed valve is left to run at a high temperature before cooling down. The wedge may become stuck between the body seats as the valve's body cools and contracts, making opening the valve very challenging or nearly impossible.

Minimal Fluid Resistance

The flow resistance of the parallel slide gate valve is low. Higher pressure valves typically have a venturi design bore to minimize pressure loss, whereas lower pressure rating valves have a full bore opening. It also lasts longer than conventional gate valves because of the little fluid pressure drop, which causes little to no harm.

Superior Sealing Performance

Parallel valves are perfect for pipelines transporting vital fluids because they offer a tight seal against any flow. Parallel slide gate valves are better at sealing for the following reasons:

• Perfect for applications with varying operating temperatures
• Easy to operate due to being position seated
• Eliminates possibility of thermal locking

Bidirectional

Any direction of flow can be used to operate the parallel slide gate valve. Installing extra valves to utilize in the opposite direction is not necessary if your pipeline has a two-way flow.

Advantages of Parallel Slide Gate Valves: Concluding Remarks

You don't need any persuasion to buy or replace your wedge gate valves with parallel slide gate valves at this point. The parallel slide gate valve is the only valve that can function as a bidirectional valve with better sealing performance in applications involving high temperatures. Get in touch with our professionals to talk about your issues and discover long-term fixes.