News/Blog
News/Blog
01, 1970
The flat gate valve is a type of sliding valve that uses a flat, parallel gate as its closing member. It is designed primarily for on‐off service (rather than flow control) in pipelines carrying liquids and gases. Its structure and design have several notable features that enhance its operation and reliability:
The valve's closure element is a flat gate that can be configured as a single or double gate. In the double gate version, a spreading or diversion mechanism helps supplement the sealing force.
A common design element is the use of an O‑ring seal in conjunction with a floating valve seat. This arrangement allows the medium pressure to push the gate against the seat, ensuring a tight, two‑way seal (both inlet and outlet).
Because the sealing is assisted by the medium’s own pressure, the required opening and closing torque is significantly lower compared to conventional valves. This makes operation more energy‑efficient and reduces wear on the actuator.
When fully open, the valve presents a straight, unobstructed channel. This design minimizes flow resistance and pressure drop, which is particularly beneficial in pipelines that require cleaning (for example, by using a pig or wool ball).
The valve typically features a packing arrangement with self‑sealing capability. An auxiliary grease injection system is often integrated into the packing box to lubricate seals and achieve zero leakage, reducing the need for frequent adjustments.
Upon closure, the valve is designed to automatically vent any high pressure from the internal cavity, enhancing operational safety.
The overall structure is fully enclosed, which not only protects the internal components from external contaminants (such as dust or moisture) but also allows the valve to operate reliably under various weather conditions.
Thanks to its floating seat design, the valve can achieve effective sealing regardless of the flow direction. This is critical in applications where the fluid might reverse flow.
The low torque and self‑sealing packing system contribute to a longer service life and easier maintenance. Consumable parts, such as seals or wearing elements, can be replaced without disrupting the pipeline operation.
The flat gate valve is suitable for a range of pressures and temperatures (typically up to 15.0 MPa and within a temperature range from –29°C to 121°C) and is widely used in oil and gas pipelines, transportation pipelines, waterworks, and other industrial applications.
Its design makes it particularly well‑suited for media containing suspended particles, as the valve’s sealing surfaces remain in constant contact during operation, preventing the ingress of debris that could compromise the seal.
A flat gate valve is a sliding valve with a parallel gate. The gate can be a single plate or a double plate with a spreading mechanism in between. The sealing pressure against the valve seat is controlled by the medium’s pressure acting on the floating gate or floating valve seat. In dual-shutter flat gate valves, the spreading mechanism between the shutters compensates for this pressure.
1. Floating Valve Seat Structure – Equipped with an O-ring seal and pre-tightening force, the valve seat ensures bidirectional sealing at both the inlet and outlet. This structure reduces switching torque by half compared to standard valves, making operation easier.
2. Low Flow Resistance – When fully opened, the smooth channel minimizes flow resistance, resulting in negligible pressure loss. The pipeline can also be cleaned using a hairball.
3. Self-Sealing Packing – The self-sealing packing structure requires minimal adjustments, enabling smooth operation and reliable sealing. Additionally, an auxiliary grease injection system ensures absolute sealing reliability, preventing leakage issues common in conventional valves.
4. Automatic Pressure Relief – When closed, the valve automatically releases excess pressure from the inner cavity, enhancing safety and ease of use.
5. Weather-Resistant Design – The fully enclosed structure provides excellent protection, making it suitable for all-weather applications.
1. Oil & Gas Transmission Pipelines – Suitable for Class 150–900 / PN 1.0–16.0 MPa, with a working temperature of -29°C to 121°C. Flat gate valves with a pilot port facilitate pipeline cleaning.
2. Refined Oil Transportation & Storage – Used in refined oil pipelines and storage systems.
3. Oil & Gas Extraction – Installed in wellhead devices and oil extraction machinery.
4. Suspended Particle Media Pipelines – Ideal for applications involving media with suspended particles.
5. City Gas Pipelines – Used in urban gas distribution networks.
6. Waterworks – Applied in municipal water supply systems.
The flat gate valve offers minimal flow resistance, with its non-reducing design providing resistance comparable to that of a short pipe. When equipped with a pilot hole, it can be installed on pipelines and cleaned directly using a vacuum cleaner.
Due to the movement of the gate affecting both valve seat surfaces, the flat gate valve is suitable for mediums containing suspended particles. Its sealing surface is self-positioning, preventing damage from the valve body’s thermal deformation.
Moreover, thermal expansion of the valve stem does not overload the sealing surfaces, even if the valve is closed in a cold state. Additionally, a flat gate valve without a pilot hole does not require high precision in the closing position of the gate, allowing its opening and closing positions to be controlled via the stroke of the electric actuator.
1. For oil and natural gas transmission pipelines, opt for a flat gate valve with either a single or double gate. If pipeline cleaning is necessary, choose a rising stem flat gate valve with single or dual gate pilot holes.
2. For refined oil transportation pipelines and storage facilities, use a flat gate valve with a single or double gate, without a diversion hole.
3. For oil and natural gas extraction wellhead equipment, select a single-gate or double-gate flat gate valve with guide holes on the concealed stem floating valve seat.
4. For pipelines carrying mediums with suspended particles, choose a small flat gate valve.
5. For city gas transmission pipelines, use a single-gate or double-gate soft-sealed rising stem flat gate valve.
6. For urban water supply systems, select a flat gate valve with a single or double-layer gate, without a guide.
In essence, the use structure of a flat gate valve emphasizes:
- A simple, robust, and reliable on‑off mechanism with a parallel gate design.
- Enhanced sealing performance via a floating valve seat and O‑ring configuration.
- Low operational torque and minimal flow resistance when fully open.
- An integrated self‑sealing and grease injection system for improved maintenance and zero leakage.
- Versatility in handling various media and operating conditions.
These features combine to make the flat gate valve an ideal choice for critical pipeline applications where both effective sealing and minimal interference with flow are essential.
