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 PN1.616.0MPa 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.
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Electric Gate Valve Overview 1 Operating Principle: 2 Types of Electric Actuators: 3 Classification of Electric Gate Valves:
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.
Common types of electric actuators include rotary (quarter-turn) actuators and linear (multi-turn) actuators.
Rotary (Quarter-Turn) Actuators: These actuators work with quarter-turn valves to control the flow of pipeline fluid within a 90-degree rotation.
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.
- 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.
Electric Gate Valves Advantages and Disadvantages
1. Electric Gate Valves Advantages
2. Electric Gate Valves Disadvantages
Electric Gate Valves Applications
Overview of gate valves
Gate valves are one of the most common types of valves in the isolation category. They can be found in every refinery, chemical plant, power station, and industrial production facility, and can be manufactured in sizes ranging from DN6 to . gate valves are chosen for the primary purpose of fluid shutoff. It is for this reason that gate valves are often referred to as "cut-off" or "blocking" valves.
Gate valves are generally used in the fully open or fully closed operation. When fully open, the pressure drop through the gate valve is very small; when fully closed, the pressure sealing performance is very good. Due to the fit of the gate and seat ring, there is almost no leakage when the gate valve is closed. However, in the case of very low back pressure (generally not less than 0.34 bar, 1 bar = 105 Pa), some leakage may occur.
Another advantage of gate valves is that they usually open and close very slowly, a feature that prevents fluid water hammer effects from damaging the piping system.
The main limitation of gate valves is that they cannot be used in throttling conditions. When gate valves are used in dry throttling service, the fluid often has a high flow rate near the seat, which can cause erosion. Also in the partially open state, the gate will swing under the impact of the medium, which will cause damage to the seal. Usually, gate valves are more prone to seat and gate seal surface wear than globe valves, and the repair of such wear is difficult to be accomplished by means of grinding and polishing.
For more information, please visit ANSI Standard Flange Type Gate Valve.
Because the structural characteristics of the gate valve are very suitable for large-scale devices, its application range is expanding, and to high temperature and high-pressure development. The maximum diameter of the gate valve has reached DN, in the ammonia plant has been a large number of high-pressure gate valve PN320, for oil and gas drilling wellhead gate valve working pressure up to 138MPa. manufacturing a high-temperature and high-pressure gate valve is the key to solving the problem of wedging the gate plate due to temperature changes, as well as ensuring its reliable sealing performance. To this end, the gate and seat sealing structure should be studied and improved. Resilient seats and resilient floating seats have begun to be applied to enable the gate valve to achieve inlet sealing, outlet sealing, or double sealing of import and export.
Composition of gate valve
Gate valve, also called the gate valve, mainly consists of the valve body, bonnet, gate, stem, seat and seal packing, and other parts.
The gate valve is the opening and closing member (gate), driven by the valve stem, along the seat (sealing surface) to do a linear movement of the valve. Generally, the gate valve can not be used to regulate the flow, only a cut-off device can be used, either completely open or completely closed. Among the various types of valves, the gate valve is the most widely used one. It is suitable for both normal temperature and pressure conditions, as well as high and low temperature and high and low-pressure conditions, and can be applied to a variety of different media through the selection of different materials.
The advantages of the gate valve:
Small fluid resistance. Gate valve body's internal media channel is straight, the media flow through the gate valve does not change its flow direction, so the fluid resistance is small.
structure length (the distance between the two ends connected to the pipe) is small. As the gate is disc-shaped, is placed vertically in the body of the valve, and the globe valve flap (also disc-shaped) is placed parallel to the body of the valve, so compared with the globe valve, its structure length is smaller. Such as the PN16, and DN150 globe valve, the structure length of 480mm, while the same parameters of the gate valve structure length are only 350mm.
opening and closing less effort. When opening and closing the gate movement direction is perpendicular to the direction of media flow, while the shut-off valve flap is usually closed in the direction of movement and seated in the opposite direction of media flow, and therefore must overcome the force of the medium. Therefore, compared with the shut-off valve, the opening, and closing of the exposition valve is more labor-saving.
Media flow direction is not restricted. The medium can flow from both sides of the gate valve in any direction through the gate valve and can achieve the purpose of connection or cut off. Easy to install, suitable for the flow direction of the medium may change in the pipeline.
When fully open, the sealing surface is subject to minimal erosion of the working medium.
The structure of the body is relatively simple, and the manufacturing process is good.
Disadvantages of the gate valve:
Sealing surface is easy to produce abrasions. When opening and closing the gate and the valve seat in contact with the relative sliding between the two sealing surfaces, under the action of the medium thrust easy to produce abrasion, thus destroying the sealing performance, and affecting the service life.
more parts, the structure is more complex, manufacturing and maintenance are more difficult, compared with the cost of the globe valve are higher.
shape size and opening height are larger, and the space required for installation is larger.
Generally gate valves have two sealing pairs, which adds some difficulties to processing, grinding, and maintenance.
The operating stroke is large, and the opening and closing time is long. Since the gate needs to be completely lifted to the top of the seat channel when opening, and all the gate needs to fall down to block the seat channel when closing, so the opening and closing stroke of the gate is large, and the opening and closing time is long.
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