Gate valves with flanged end connections remain hugely popular across many industries. Their robust construction and straightforward operation have made them workhorses on piping systems everywhere. However, like any valve type, flanged gate valves also have their limitations.
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Let’s take a balanced look at the main advantages and disadvantages.
Flange Gate Valves – Key AdvantagesHere are some of the key advantages of Flanged gate valves:
One of the biggest benefits of flanged gate valves is the convenience factor. Those flanged end connections make installation a breeze – simply bolt the valve body between matching pipe flanges. Likewise, removing the valve for maintenance is just as straightforward.
When in the full open position, the wedge-shaped gate drops completely out of the flow path. This provides an unobstructed, full bore opening equal to the pipe ID. The lack of any flow obstructions helps minimize pressure drop and resistance to flow.
Gate valves have a delightfully uncomplicated design. The two-piece body houses a gate that slides perpendicular to the flow path between parallel seats. With minimal moving parts and no complex mechanisms, there’s less to go wrong or require extensive maintenance.
Flanged Gate Valves – Key DisadvantagesFlanged gate valves certainly have a few limitations. Let’s discuss some of the key disadvantages of flanged gate valve:
One of the biggest safety concerns with gate valves is the possibility of the valve stem blowing out. If the stem packing leaks and goes untended, the buildup of pressure can forcibly eject the entire stem — creating a dangerous projectile. Proper maintenance is critical.
Speaking of packing, leakage around the stem is another common issue as the valve cycles open and closed over its lifetime. The sliding motion and exposure inevitably causes the packing material to degrade and harden, requiring repacking.
Gate valves are designed for straight open or closed service, not modulating flows. Attempting to throttle the valve with the gate partially open can cause vibration, hunting, and excessive wear on the gate and seats over time. Using them for frequent operation also increases packing deterioration.
The larger the valve size, the greater the torque required to open and close the gate against flow forces and friction. This can make manual operation very difficult, often necessitating a gear operator or actuator.
ConclusionLike any valve type, flanged gate valves have their advantages and limitations. They can provide an economical, reliable shutoff solution for liquid and gas systems that don’t require frequent cycling or modulation. Just be sure to properly assess the operating conditions.
When you need quality flange gate valves from a trusted manufacturer, Xintai Valve has the experience to meet your specifications. Our team leverages decades of valve expertise to deliver dependable products you can count on.
HTML 模块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 4200. 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.
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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.
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 DN4200, 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:
①Small 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.
② 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.
③ 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.
④ 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.
⑤ When fully open, the sealing surface is subject to minimal erosion of the working medium.
⑥The structure of the body is relatively simple, and the manufacturing process is good.
Disadvantages of the gate valve:
①Sealing 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.
② more parts, the structure is more complex, manufacturing and maintenance are more difficult, compared with the cost of the globe valve are higher.
③ shape size and opening height are larger, and the space required for installation is larger.
④Generally gate valves have two sealing pairs, which adds some difficulties to processing, grinding, and maintenance.
⑤ 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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