Electric Gate Valve: Introduction, Advantages, Disadvantages, Applications
Nov.08.2024
An electric gate valve is primarily used for the on-off control of pipeline media. It is suitable for various systems including petroleum, chemical, hydraulic, and thermal power stations with a nominal pressure range of PN1.6–16.0MPa and an operating temperature range of -29°C to 550°C. This valve is a critical device for controlling the flow or conveying of powders, granules, particulate materials, and small pieces. This article provides further details on electric gate valves.
Ⅰ Electric Gate Valve Overview
1 Operating Principle:
An electric gate valve uses electrical energy to power an electric actuator that drives the valve. The actuator connects to the valve stem, moving the valve disc up and down to open or close the valve, thereby controlling the flow of media through the pipeline. With the addition of control boxes and other accessories, the valve can be operated remotely, providing convenience and efficiency.
2 Types of Electric Actuators:
Common types of electric actuators include rotary (quarter-turn) actuators and linear (multi-turn) actuators.
① Rotary (Quarter-Turn) Actuators: These actuators work with quarter-turn valves to control the flow of pipeline fluid within a 90-degree rotation.
② Linear (Multi-Turn) Actuators: These actuators work with linear valves to control the flow by moving the valve disc up and down. They are typically used in systems requiring a high degree of automation.
3 Classification of Electric Gate Valves:
- By Stem Type: Rising stem gate valves and non-rising stem gate valves.
- By Structure: Flat gate valves and wedge gate valves.
- By Standard: GB (Chinese standard), ANSI (American standard), DIN (German standard), and JIS (Japanese standard) gate valves.
- By Connection Type: Flanged gate valves, welded gate valves, threaded gate valves (including internal and external threads).
- By Pressure Rating: High-pressure gate valves and low (medium) pressure gate valves.
- By Actuation Method: Electric gate valves, pneumatic gate valves, manual gate valves.
- By Material: Stainless steel gate valves, forged steel gate valves, cast steel gate valves, carbon steel gate valves, cast iron gate valves, copper gate valves (including bronze and brass), ceramic gate valves, plastic gate valves.
Ⅱ Electric Gate Valves Advantages and Disadvantages
1. Electric Gate Valves Advantages
- High Reliability: Smooth operation and tight sealing effectively prevent leaks.
- High Degree of Automation: Easy to operate via electric actuators, suitable for remote control and automation systems.
- Wide Application Range: Can withstand high-temperature and high-pressure conditions, suitable for various media and industrial fields.
- Energy Efficient: Low friction during opening and closing saves energy.
- Easy Maintenance: Simple structure makes maintenance and repairs convenient, reducing downtime.
- Low Fluid Resistance: The straight-through channel offers low fluid resistance, ideal for pipeline systems requiring low pressure drop.
2. Electric Gate Valves Disadvantages
- Large Size and Heavy Weight: Compared to other valve types, electric gate valves are typically larger and heavier, taking up more space.
- Long Opening/Closing Time: The large travel distance of the valve disc results in a longer opening and closing time, not suitable for applications requiring rapid operation.
- High Cost: The electric actuator and high-pressure valve body materials result in higher overall costs.
- Complexity: The complexity of the electric actuator increases the complexity of the control system, requiring specialized operation and maintenance.
- High Installation Requirements: Due to their size and weight, installation requires sufficient support and space.
Ⅲ Electric Gate Valves Applications
1. Application of Electric Gate Valves in Coal Mining
With the increasing automation of coal mining operations, manual gate valves on underground pipelines are no longer sufficient to meet the demands of automated control. Some mines have adopted hydraulic valves and electro-hydraulic valves during upgrades, but the seals of these valves tend to age quickly, requiring annual maintenance. Additionally, manual pressure reduction is needed to open the valves when there is a significant pressure differential, and these valves cannot be directly integrated into DCS (Distributed Control Systems). In contrast, electric gate valves offer a cost-effective solution with the capability for remote control.
2. Application of Electric Gate Valves in High-Temperature Steam
Typically, customers compare and choose between gate valves and ball valves. While ball valves offer higher quality and faster operation, the metal seals or special high-temperature seals required for ball valves in high-temperature applications are very expensive. Electric gate valves, on the other hand, present the most cost-effective choice for high-temperature steam applications, serving effectively as isolation valves for water and steam.
One of the most common issues with gate valves in steam systems is leakage. Leakage can result from improper installation or maintenance, such as failing to check for corrosion or wear of parts. Additionally, if the valve size is not appropriate for the application, it can lead to pressure imbalance and subsequent leakage.
To prevent leakage, it is crucial to ensure proper installation and maintenance of the valve. This includes inspecting parts for corrosion or wear and ensuring that the valve size and pressure rating are suitable for the application. Regular inspections are also essential to ensure that all moving parts are properly lubricated and functioning correctly.
3. Application of Electric Gate Valves in the Paper Industry
In the paper industry, the most widely used valves are pulp valves (thin gate valves), which account for 50% of the total valve demand in this sector and are ideal for thick pulp applications.
In addition, electric actuated gate valves are extensively used in industries such as oil and gas, water treatment, power generation, and chemical processing. They are commonly employed in systems requiring precise flow control, isolation, or fluid transfer.
