Gate valves: advantages, disadvantages and operating principle

Everything you need to know about gate valves and their main advantages

Gate valves are flow control devices commonly used in many industries, due to their ability to provide a hermetic and reliable closure. Their use is critical in areas such as the oil and chemical industries, where corrosion resistance and the ability to handle aggressive fluids are essential, but also in water and water management systems. The wide spread of gate valves is due to their versatility and simple but robust structure, which makes them suitable for operating in extreme conditions and to withstand high pressures without compromising their functionality. 

 

Understanding the technical characteristics, advantages and disadvantages of different types of gate valves is essential to select the most suitable model for specific operational needs. Choosing the right valve not only affects the efficiency and safety of industrial processes, but can also lead to significant savings in terms of maintenance costs and plant life. An in-depth knowledge of this type of valves is therefore essential for engineers and operators in the sector who aim to optimize the performance and safety of their infrastructures.

 

Let’s see in more detail what are gate valves, how they work and what are the main advantages and disadvantages of their use. 

What are gate valves?

 

Gate valves are linear motion valves that allow the control of fluid flow within pipes, offering a hermetic closure or total opening of the passage. Their main purpose is to completely isolate a section of a pipeline network, ensuring that there is no fluid flow when the valve is closed. This makes them ideal for applications where flow needs to be interrupted for maintenance, safety or process control operations.

 

The shutters are made up of several fundamental parts: the valve body, which constitutes the main structure and houses all the other components; the shutter, which is the moving component responsible for opening and closing the fluid passage; and the actuator, which is the mechanism that moves the shutter. The actuator can be manual, pneumatic, hydraulic or electric according to the specific requirements of the application. 

 

Gate valves can be made of different materials, depending on the operating conditions and type of fluid they need to handle. Common materials include cast iron, bronze and brass. The choice of material is crucial as it must be compatible with the fluid being processed and must withstand the specific temperature and pressure conditions of each application. Knowing the characteristics of various materials is therefore essential to ensure safe and efficient operation of valves in various industrial sectors.

 

Operation principle of gate valves 

 

The operation principle of gate valves is relatively simple but extremely effective: the shutter (which as we have seen is the movable part inside the valve) moves vertically to open or close the passage of fluid. When the valve is fully opened, the shutter lifts, allowing fluid to flow freely and with minimal resistance. 
Conversely, when the valve is closed, the shutter lowers down to fully fit into the valve seat, blocking the flow of fluid and ensuring a hermetic closure. This type of closure is essential in many industrial applications as it prevents any unwanted fluid flow, thus ensuring the safety and integrity of the installations.

 

The movement of the shutter is controlled by an actuator, which can be manual, pneumatic, hydraulic or electric. A manual actuator usually consists of a handle or wheel that the operator turns to move the shutter. Pneumatic, hydraulic and electric actuators use compressed air, hydraulic fluids or electrical power to automate the movement of the shutter, making remote control and automated valve management possible.

 

Gate valves are designed to work with a variety of fluids, including liquids such as water and oil, gas and biphasic mixtures. However, they are not particularly suitable for high viscosity fluids or applications requiring partial flow control, as their structure is designed for full opening and closing operations rather than intermediate adjustments.

 

Another crucial aspect of gate valve operation is the seal between the shutter and the valve seat. This seal can be ensured by seals made of resilient materials or metal surfaces that provide precise closure. In rigid wedge models, the shutter fits perfectly into the seat, while in elastic wedge models, the shutter is designed to adapt to the deformation of the seat caused by changes in temperature and pressure, thus ensuring effective closure in all operating conditions.

 

Advantages and disadvantages of gate valves 

 

Gate valves are the ideal choice for various industrial applications and can offer several advantages. They are distinguished primarily by their ease of use and installation, but also by the low maintenance requirement. With proper care, these valves can work without problems for many years. This translates into significant savings in terms of costs and maintenance time, also reducing downtimes. 
In addition to these aspects, the main advantages of gate valves include: 

• resistance and long life: made of resistant materials, such as bronze and cast iron, these valves are built to last. Their robustness ensures long service life even under difficult operating conditions and high resistance to extreme temperatures and pressures.  This makes them particularly suitable for sectors such as the oil industry, chemicals and water management where maximum reliability and operating accuracy are required; 
• versatility:  the shutters can be installed in different positions, both vertically and horizontally, and can adapt to various applications and fluids. This flexibility makes them suitable for a wide range of pipe configurations, ideal even for complex installations and transport infrastructures; 
• excellent seal: the sealing surfaces of the gate valves are designed to fit perfectly, ensuring effective insulation even under high pressure. This is essential to prevent leakage of hazardous fluids in critical industrial applications, such as the transport of natural gas or aggressive chemicals; 
• low operating costs: with their long life and minimal maintenance, gate valves can help reduce overall operating costs. The savings from reduced maintenance costs and extended operating life are significant, making it a long-term cost effective choice for industrial plants. 

Despite the many advantages, gate valves may also have some disadvantages which it is important to consider when determining whether they are more or less suitable for specific applications. First of all, these valves have poor flow-control capability. This limits their use in areas where partial regulation is necessary, such as in some chemical processes or precise flow control in heating, ventilation and air conditioning systems. 

 

Another disadvantage is the tendency to clog when used with high viscosity fluids or solids containing particles. Although knife variants can handle these fluids better, standard valves may suffer from sediment build-up, which can compromise airtight closure and require more frequent maintenance. Therefore, in applications such as waste water treatment or in industries with particularly dense fluids, they may not be the best choice.

 

In addition, the slow opening and closing time of gate valves can be a problem in applications that require rapid flow interruption for safety reasons. In cases where it is crucial to immediately block the flow of fluid, such as in emergency or safety systems, gate valves may not be the most effective solution.

 

ECI gate Valves: a complete selection of products for different applications 

 

ECI is a manufacturer of valves for industrial applications that offers a wide range of gate valves, each with specific characteristics, which make them suitable for different operational needs. Among the various products offered are flanged valves, such as the G507 or G503 gate valve, which ensure a robust and safe connection to pipes, reducing the risk of leakage and facilitating installation and maintenance operations. 

 

Gate valves with a protruding and non-protruding rod are also available. Valves with an overhanging rod offer the advantage of greater visibility of valve position, making visual inspection and maintenance easier. This type of product is particularly useful in applications where it is necessary to monitor the opening or closing state of the valve frequently. 
The BR 582 bronze gate valve with a protruding rod, for example, is a highly specialized and versatile product designed to deliver high performance in a variety of industrial applications. Compliant with BS 5154 and MSS SP-80 standards, this valve is distinguished by its robustness and reliability and can operate in systems with high pressures, guaranteeing maximum safety and operational stability.

 

All ECI gate valves are made of high-quality, high-strength materials such as bronze, brass and cast iron to ensure maximum durability and resistance in harsh operating environments. The valves are also designed to provide excellent sealing, minimizing fluid losses and ensuring accurate and efficient plant operation. 

 

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