Gate valves are a product of the industrial revolution. While some valve designs such as the globe and plug valve have been around longer, the gate valve dominated the industry for many decades, only recently ceding substantial market share to ball and butterfly valve designs.
If you want to learn more, please visit our website.
The gate valve differs from ball, plug and butterfly valves in that the closure element, called the disc, gate, or obturator, rises on the base of a stem or spindle out of the waterway and into the valve top, called the bonnet, by means of multiple turns of the spindle or stem. These valves that open with a straight-line motion are also called multi-turn or linear valves and differ from quarter-turn styles, whose stems rotate 90 degrees and generally don&#;t rise.
An example of the original wedge-style gate valve designed by James Nasmyth in . This one dates from -. Photo credit: Greg Johnson
Gate valves are available in dozens of different materials and several pressure classes. They range in size from fit-in-your-hand NPS ½ inch, through big-as-a-truck NPS 144 inch. Gate valves are constructed of castings, forgings or weld-fabricated assemblies, although casting designs dominate.
One of the most desirable aspects of gate valves is their ability to open fully and leave the flow bore virtually free of encumbrances or friction. An open gate valve offers about the same amount of resistance to flow as a section of pipe of the same port size. As a result, gate valves are still strongly considered for blocking or on/off applications. In some valve nomenclature, a gate valve is called a block valve.
Gate valves are generally bad choices for regulating flow or operating in any orientation other than fully open or fully closed. Using a partially open gate valve for throttling or regulating flow can result in either damage to the disc or body seat rings, due to the seating surfaces banging against one another in the partially open, turbulence-inducing flow environment.
From the outside, most gate valves look somewhat similar. However, inside there are a host of different design possibilities. Most gate valves consist of a body and bonnet that contains a closure element, called a disc or a gate. The closure element is attached to a stem that passes through the bonnet of the valve, ultimately interfacing with a handwheel or other actuation device to operate the stem. Pressure around the stem is contained with a packing material that is compressed into a packing area or chamber.
Gate valves generally have a low total cost of ownership. They are relatively easy to manufacture and are easy to repair. Photo credit: Greg Johnson
The motion of a gate valve&#;s disc upon the stem dictates whether the stem rises during opening or threads into the disc. This reaction also defines the two major stem/disc styles of the gate valve: the rising stem or the non-rising stem (NRS). The rising stem is the overwhelmingly popular style of stem/disc design for the industrial market, while the non-rising style has merited longtime favor with the waterworks and plumbing industry segments. Some marine applications where gate valves are still used and space is tight, also utilize the NRS style.
The Most Common stem/bonnet design in use on industrial valves is the outside screw and yoke (OS&Y). The OS&Y design is preferred for corrosive environments because the threads are outside the fluid containment area. It also differs from other designs in that the handwheel is attached to a bushing at the top of the valve yoke, and not to the stem itself, thus the handwheel does not rise as the valve is opened.
The word &#;trim&#; is often overheard when valve professionals are talking about industrial gate valves. Trim has nothing to do with how slim and fit a valve is; rather, it refers to the internal components of a valve that are exposed to great stress or subject to a harsh combination of erosion and corrosion. In a gate valve, the trim components are the stem, disc seating area, body seats and backseat, if applicable. Common utility bronze or brass valves usually have trim parts of the same material as the body and bonnet. Cast and ductile iron valves have either all iron trim components or occasionally bronze trim. The term for an iron valve with bronze trim is &#;iron body, bronze mounted&#; (IBBM).
This is one of the eight 90-inch gate valves located in the bowels of Hoover Dam. Photo credit: Greg Johnson
Steel valves can be furnished with a number of different trims. Stellite, Hastelloy, 316ss, 347ss, Monel and Alloy 20 are some of the materials regularly used for gate valve trim.
The heart of the gate valve is the closure element, which can be of two designs, either the wedge or the parallel seat. The wedge design is the most popular and has been around since invented by famous British engineer James Nasmyth in . The wedge style utilizes the slightly angled disc mating with the same angled valve body seats to affect a tight closure. These valves are seated by applying torque to push the disc firmly into the seats. Three types of wedge disc are available:
The solid wedge has been around the longest and at one time virtually all wedge gates were the solid type. The drawback to a solid design is that it does not have any flexibility and if there is any valve body/seat distortion due to extreme temperature fluctuations or pipe stresses, the solid disc can become jammed in the seats. The solid disc is still standard on bronze, cast iron, water service and compact carbon steel valves (API 602 type).
The flexible wedge type is just that: flexible. By the addition of a groove or slot around its periphery, the flexible disc can adapt to temperature changes and adverse piping stresses without binding. The flexible design also is a little easier to manufacture in that minor imperfections in the seating surface angles can be compensated for by the disc&#;s flexibility. The flex-wedge design is by far The Most Common type seen on commodity gate valves used in industrial applications.
The split wedge type consists of a two-piece design with mating surfaces on the back side of each disc half. These mating surfaces allow the downward stem thrust to be uniformly transferred to the disc faces and onto the seats. This flexible design also provides protection against jamming due to thermal expansion. A disadvantage to the split design is that in dirty services, residue or debris can cake in between the disc halves, causing the valve to improperly seat or even jam. Split wedge designs are commonly found on stainless steel and high alloy valves, as well as many small bronze valves.
Space is at a premium on ships and NRS gate valves have been used in these applications for decades because they require less room than OS&Y gate valve designs. Photo credit: Greg Johnson
Wedge gates are guided by grooves or ribs cast or welded into the body of the valve. These wedge guides keep the disc in alignment as it opens or closes and also keeps the disc from sliding against the downstream seat during opening and closing.
The other gate valve disc style is the parallel seat design. Parallel seats may be spring loaded to provide for a tighter seal or create positive sealing in the upstream direction. Parallel seated valves are position seated, in that the position of the disc dictates the sealing efficacy, and not the amount of force (torque) applied to the disc by the stem.
Gate valves generally are made of two principal parts: the body and the bonnet. These comprise the pressure-containing envelope of the gate valve. There are a variety of designs for the interface of these two components.
The screwed joint is the simplest design. However, it is only used for inexpensive, low-pressure bronze valves.
The union joint is also primarily used on bronze valves, but the union design allows for easier disassembly for repair and maintenance.
The bolted-bonnet joint is the most popular joint and it is used on the vast majority of gate valves in industrial use today. Unlike threaded and union bonnet valves, the bolted-bonnet connection requires a gasket to seal the joint between the body and bonnet.
The pressure-seal joint is energized by the fluid pressure in the valve body acting upon a wedge shaped, soft iron or graphite gasket wedged between the body and bonnet. On a pressure-seal valve, the higher the body cavity pressure, the greater the force on the gasket. Pressure-seal bonnets are used extensively for high-pressure high-temperature applications, such as the power industry.
Welded bonnets are a very popular body-bonnet joint for compact steel valves in sizes ½ inch through 2 inches and pressure classes 800 through , where disassembly is not required.
Also in the gate valve family are knife and sluice gates. The bonnetless knife gate is especially suited for use in slurries such as in pulp and paper mills.
This small gate valve is a common design in sizes NPS 1/2-2 inches. The tapered disc is clearly visible. Photo credit: Greg Johnson
Knife gates are very thin, only slightly wider than their closure element (disc). Because of their unique geometry and thin cross-section, knife gates are limited to low pressure applications.
In appearance, the sluice gate doesn&#;t look like it even belongs in the gate valve family; however, based upon its sliding disc design, it is characterized as a gate valve. Sluice gates are limited to very low pressures &#; in most cases, simple head pressure. They are used primarily in wastewater and irrigation systems.
While the quarter-turn valve has achieved a large chunk of the gate valve market share over the past 50 years, there are still industries that rely heavily on them, including the oil and gas industry. Crude or liquid pipelines are still the home to parallel seat gate valves, despite the inroads that ball valves have made on the gas pipeline side.
In the larger sizes, the gate valves are still the primary choice for the refining industry for most applications. The robustness of design and total cost of ownership (which includes the economics of repair) are points that make this legacy design desirable.
An NPS 36 pipeline-style parallel seat gate valve is unloaded at one of the U.S. Strategic Petroleum Reserve locations. Photo credit: Greg Johnson
Application-wise, many refinery processes utilize temperatures above the safe operating temperature of Teflon, which is the primary seating material in floating ball valves. The high-performance butterfly valve and metal-seated ball valve are beginning to see more use in refinery applications, although their total cost of ownership is often higher than that of the gate valve.
The waterworks industry segment is still dominated by iron gate valves. They are reasonably inexpensive and long-lasting, even in buried applications.
The power industry utilizes alloy gate valves for applications involving very high pressure and very high temperature. Although some newer Y-pattern globe valves, and metal-seated ball valves designed for blocking service are found in power plants, gate valves still find favor for plant designers and operators.
A trio of NPS 36, NRS gate valves are seen in manifolds at a water treatment facility. Photo credit: Greg Johnson
Steel and iron are the most popular materials for gate valve construction, with steel being the choice for most industrial applications and iron for water, wastewater and heating, ventilation and air-conditioning (HVAC). Other materials popular for gate valve construction include stainless steel, bronze and high alloys such as Hastelloy and Inconel.
Standards for the design and construction of gate valves are published by the American Petroleum Institute (API), Manufacturers Standardization Society (MSS), American Waterworks Association (AWWA) and American Society of Mechanical Engineers (ASME).
Gate valves are still the primary choice for many service applications. Their cost of manufacture to value ratio is still very high. On typical petrochemical and refining projects today, the percentage of gate valves on the requisition is about 60%.
Mark Twain once said, &#;The rumors of my death have been greatly exaggerated.&#; Although the ball, plug and butterfly valve segments have been gaining market share for decades, the venerable gate valve can respond the same way &#; the rumors of its demise have been exaggerated.
Greg Johnson is president of United Valve. He is a contributing editor to VALVE Magazine and a current Valve Repair Council board member. He also serves as chairman of the VALVE Magazine Advisory Board, is a founding member of the VMA Education and Training Committee and is past president of the Manufacturers Standardization Society. Reach him at .
Landscape Source: Greg Johnson
An Introduction to Axial Flow Check Valves
Check valves are self-actualizing devices that respond to both pressure and flow changes in a piping system.
Introduction to Pressure Relief Devices - Part 1
When the pressure inside equipment such as boilers or pressure vessels increases beyond a specified value, the excess pressure may result in a catastrophic failure.
Air Valves in Piping Systems
Liquid piping systems are prone to collecting air from incoming fluids, pumps and connections.
Gate valves may seem like ordinary parts, but they play a critical role in how liquids and gases move around. These valves help control fluid flow, ensuring everything works smoothly. The interesting thing is that gate valves come in numerous forms, each of which is designed for a specific job. But how many different types of gate valves are there?
Here you will find out more about the different types of gate valves, how many types of gate valves there are, what they do, and how they are applied across various industries.
Wedge Gate Valves
Wedge gate valves are designed with a gate that resembles a sloping wedge. When the valve is closed, this wedge-shaped gate fits snugly between two inclined seats, creating a secure seal. This design ensures effective shut-off and flow control.
But in what instances are these valves used? These valves find application across various scenarios, from managing the flow of chemicals in industrial settings to regulating water distribution in municipal pipelines. Their reliability stems from the simplicity of their design, making them a suitable choice where dependable fluid control is crucial.
Also known for their ability to offer a balance between versatility and reliability, wedge gate valves have an uncomplicated structure that allows seamless operation and enduring performance, even in demanding conditions. Wedge gate valves quietly excel at their role, making them the ideal option in situations where consistent performance is important.
Goto solid to know more.
Wedge gate valves are known for their versatile functionality, making them a dependable choice. They also can blend seamlessly into diverse industrial contexts.
Parallel Slide Gate Valves
Parallel slide gate valves (also sometimes referred to as split gate valves) are engineered to enable the controlled movement of fluids within pipelines. They achieve this by offering a clear and uninterrupted pathway for fluid control. This design feature makes split gate valves particularly effective in applications where minimising pressure drops and ensuring efficient flow are imperative.
In practice, parallel slide gate valves manage the directional flow of liquids and gases by smoothly guiding them through their precisely designed internal components. These gate valves thrive in scenarios that demand both optimal flow efficiency and pressure management. They can be used in industries from chemical processing plants to oil refineries, where precise fluid control is integral to the operational success of various processes.
Parallel slide Gate Valve Design allows for precise fluid modulation, catering to industries where precise control is essential. Thanks to their compact size, they shine as guardians of seamless operations, making them easy to install.
Slab Gate Valves
Slab gate valves, recognised for their significant role in the oil and gas industry, boast a distinctive one-piece gate design that allows smooth fluid flow and minimise disruptions. These valves are particularly valuable in high-pressure situations, where maintaining a secure seal and efficient flow is vital.
In the oil and gas sector, slab gate valves play a key role in managing the movement of hydrocarbons within pipelines and processing facilities. Their robust construction and streamlined design contribute towards their effectiveness in maintaining reliable operation, even in challenging circumstances.
When compared to other valves, slab gate valves are less likely to leak, easier to repair, and require less maintenance. They&#;re also more durable than other kinds of valves.
Knife Gate Valves
Knife gate valves are another type of gate valve, but are specially engineered to handle the complex challenges posed by thick and viscous fluids that may contain solid particles. These valves feature a gate with a sharp-edged design that can effectively cut through and manage the flow of such challenging substances.
Industries like mining and wastewater treatment often rely on knife gate valves to regulate the movement of abrasive or slurry-like materials. Their unique construction and robust design allow them to perform reliably in demanding environments, ensuring efficient flow control even when dealing with problematic substances.
One of the primary benefits of knife gate valves is that they&#;re cheap and easy to actuate. They are also light in weight, have a low-pressure drop, and are known for their durability.
Parallel Expanding Gate Valves
Parallel expanding gate valves are renowned for their ability to provide a secure seal even in high-pressure conditions and provide a unique solution for fluid control. These valves feature a gate that expands against the seats when closed, ensuring a reliable and tight closure that stops any leakage.
The application of parallel expanding gate valves is particularly prevalent in sectors where maintaining airtight seals is essential. Whether in pipelines conveying volatile gases or systems dealing with hazardous liquids, these valves are critical for ensuring safety and operational efficiency.
Parallel expanding gate valves are renowned for their superior strength, durability, safety in high-temperature environments, and reduced operating torque.
Gate valve, also called plate gate valve, is mainly composed of valve body, bonnet, disc, valve stem, valve seat and sealing packing. It is one of the most common valve types in isolation valves. The main purpose of the gate valve is to cut off the fluid. For this reason, it is usually called a &#;cut off&#; valve or a &#;blocking&#; valve. The gate valve has many different structural forms, and the sealing element structure used in it is different. According to the structure of the sealing element, it can be divided into several different types.
Classified by valve stem:
According to the stem type, it can be divided into rising-stem gate valve and non rising-stem gate valve. The valve stem is the operating part of the gate valve, and its function is to transmit the opening and closing force to the opening and closing parts.
1. The trapezoidal thread of the rising-stem gate valve is placed outside the valve body and located on the upper part of the valve stem. By rotating the valve stem nut, the valve stem drives the disc to rise and fall synchronously to realize the opening and closing of the valve, so it is easy to identify the valve The opening and closing state of the machine can avoid misoperation. Since the stem nut is outside the body cavity, it is beneficial to lubrication, and the opening and closing state is intuitive and obvious, so it is widely used. However, in harsh environments, the exposed threads of the valve stem are vulnerable to damage and corrosion, even affecting operation. Its disadvantage is that the height of the valve after opening is large, usually a stroke is added to the original height of the valve, which requires a lot of operating space.
2. Non rising-stem gate valve is also called rotating stem gate valve (also called non rising-stem wedge gate valve). The stem nut is placed inside the valve body and is in direct contact with the medium and is often fixed on the disc. Through the rotation of the valve stem, the valve stem nut drives the disc to move up and down to complete the opening and closing. Usually there is a trapezoidal thread at the bottom end of the valve stem. Through the thread at the bottom end of the valve and the guide groove on the valve disc, the rotary motion is changed into linear motion, that is, the operating torque is turned into operating thrust. Since the trapezoidal thread for transmission is located inside the valve body, it is easily corroded by the medium and cannot be lubricated. The opening degree cannot be directly observed, and an indicating device is required. However, its valve stem does not move up and down, and requires small operating space, so it is suitable for occasions with limited locations and dense pipelines.
Classified by structure:
According to the structure type, it can be divided into two types: wedge gate valve and parallel gate valve. That is, the disc is a wedge type is called a wedge gate valve, and the disc is a parallel type is a flat gate valve.
1. The flat gate valve means that the sealing surface is parallel to the vertical centerline, so the sealing surfaces on the valve body and the disc are also parallel to each other. The most common type of this kind of gate valve is the double disc type. In order to make the valve body and the two sealing surfaces of the disc tightly contacted when it is closed, a double-sided thrust wedge is often used between the two discs. It is mostly used in low pressure pipelines such as small pipelines. Parallel gate valves using a single disc are also available but rare.
2. Wedge gate valve means that the sealing surface is at a certain angle with the vertical center line, that is, the two sealing surfaces are wedge-shaped gate valves. The disc of wedge gate valve is single and double. The advantage of the double disc type is that the accuracy of the sealing angle is lower, the temperature change is not easy to make the disc wedged, and the sealing surface wear can be compensated with gaskets. The disadvantage is that the structure is complex, and it is easy to stick in dry media, and the main reason is that the disc is easy to fall off after the upper and lower baffles are rusted for many years.
Classification by other methods:
According to different standards: national standard gate valve, American standard gate valve, German standard gate valve, Japanese standard gate valve
According to the connection method: flange gate valve, welded gate valve, threaded gate valve (divided into internal thread and external thread)
According to pressure level: high pressure gate valve, low (medium) pressure gate valve
According to the driving mode: electric gate valve, pneumatic gate valve, manual gate valve
Classified by material: stainless steel gate valve, forged steel gate valve, cast steel gate valve, carbon steel gate valve, cast iron gate valve, copper gate valve (also divided into bronze gate valve, brass gate valve), ceramic gate valve, plastic gate valve.
The main difference:
1. The lifting screw of the concealed rod flange gate valve only rotates and moves up and down. Only a rod is exposed. The screw cap is fixed on the disc. The disc is raised by the rotation of the screw, and there is no visible electric gate valve frame. ; The lifting screw of the rising stem flange gate valve is exposed, and the screw cap is close to the hand wheel and is fixed (not high-pressure gate valve rotation nor axial movement), the disc is improved by rotating the screw, the screw and the disc have only relative rotational movement There is no relative axial displacement, and the appearance is a gate-shaped bracket.
2. The valve stem with dark stem cannot be seen, while the stem with open stem can be seen.
3. The steering wheel and the valve stem are connected and relatively immovable when the dark stem valve is opened and closed. The valve stem rotates at a fixed point to help the valve clack move upward and downward to complete the opening and closing. The rising stem valve is driven by the turnbuckle of the valve stem and the steering wheel to raise or lower the disc.
To put it simply, the rising stem valve is that the disc and the stem move up and down together, and the steering wheel is always at a fixed point.
Is rising-stem gate valve or non rising-stem gate valve used outdoors?
For the valves installed in the outdoor valve wells, according to the experience of Tanghai valves, it is recommended that you use dark stem valves. The use of rising stem valves has the following disadvantages: 1. When the valve is opened and closed, the valve stem has to rise and fall, which takes up a lot of space. If the pipeline is not buried very deep, the valve well will hinder the opening of the valve. When the valve is opened, the valve well cover will not be closed or the valve cannot be fully opened. 2. After the number of switches is increased, the contact surface of the valve stem and the pressure flange will leak more seriously, and the packing should be replaced frequently. 3. If you don&#;t switch frequently, a part of the valve stem will be exposed to the valve body for a long time. In the humid environment of the valve well, the exposed valve stem is very easy to oxidize and rust. Once it needs to be closed, it will not be closed. Otherwise, grease must be applied frequently. In short, the maintenance workload is large. Dark stem valves do not have these problems, the probability of water leakage is also small, and of course the maintenance workload is also small. for reference only.
The opening and closing part of the rising-stem gate valve (gate valve) is a disc, and the movement direction of the disc is perpendicular to the direction of the fluid. The rising-stem gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled.
Disc has two sealing surfaces. The two sealing surfaces of the most commonly used mode disc valve form a wedge. The wedge angle varies with valve parameters, usually 50, and 2°52&#; when the medium temperature is not high. The disc of the wedge gate valve can be made into a whole, called a rigid disc; it can also be made into a disc that can produce slight deformation to improve its manufacturability and make up for the deviation of the sealing surface angle during the processing. This disc is called an elastic disc .
The types of rising-stem gate valve can be divided into wedge disc gate valve and parallel disc gate valve according to the sealing surface configuration. Wedge disc gate valve can be divided into: single disc type, double disc type and elastic disc type; parallel disc Type gate valve can be divided into single disc type and double disc type. According to the thread position of the valve stem, it can be divided into rising-stem gate valve and non rising-stem gate valve.
When the rising-stem gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, only rely on the medium pressure to press the sealing surface of the disc to the valve seat on the other side to ensure the sealing of the sealing surface, which is self-sealing. Most gate valves adopt forced sealing, that is, when the valve is closed, the disc must be forced to the valve seat by external force to ensure the tightness of the sealing surface.
The working principle of rising-stem gate valve
Rotate the hand wheel, through the advance and retreat of the thread of the hand wheel and the valve stem, raise or lower the valve plate connected with the valve stem to open and close
The rising-stem gate valve has the following advantages:
The fluid resistance is small, and the sealing surface is less eroded and eroded by the medium.
It is easier to open and close.
The flow direction of the medium is not restricted, does not disturb the flow, and does not reduce the pressure.
The shape is simple, the length of the structure is short, the manufacturing process is good, and the scope of application is wide.
The disadvantages of rising-stem gate valve are as follows:
It is easy to cause erosion and scratches between the sealing surfaces, and maintenance is difficult.
The overall size is large, opening requires a certain amount of space, and the opening and closing time is long.
The structure is more complicated.
The types of gate valves can be divided into wedge disc gate valves and parallel disc gate valves according to the sealing surface configuration. Wedge disc gate valves can be further divided into: single gate, double disc and elastic disc; parallel disc gate valves can be Divided into single disc type and double disc type. According to the thread position of the valve stem, it can be divided into rising-stem gate valve and non rising-stem gate valve.
Installation and maintenance of rising-stem gate valve:
Handwheels, handles and transmission mechanisms are not allowed to be used for lifting, and collisions are strictly prohibited.
The double disc gate valve should be installed vertically (that is, the valve stem is in the vertical position and the handwheel is at the top).
The gate valve with a bypass valve should be opened before opening (to balance the pressure difference between the inlet and outlet and reduce the opening force).
The gate valve with transmission mechanism should be installed according to the product manual.
If the valve is frequently opened and closed, lubricate at least once a month.
Structural characteristics of rising-stem gate valve:
The general gate valves used on the market for a long time generally have water leakage or rust. The company introduces the elastic seat seal gate valve produced by European high-tech rubber and valve manufacturing technology, which overcomes the defects of poor sealing and rust of general gate valves. The sealing gate valve uses the compensation effect of the elastic disc to produce a small amount of elastic deformation to achieve a good sealing effect. The valve has the obvious advantages of light switch, reliable sealing, good elastic memory and service life. It can be widely used as a regulating and intercepting device on the pipelines of tap water, sewage, construction, petroleum, chemical industry, food, medicine, textile, electric power, shipbuilding, metallurgy, energy system, etc.
Features of rising-stem gate valve:
Light weight: The body is made of high-grade ductile iron, which is about 20% to 30% lighter than the traditional gate valve, and is easy to install and maintain.
Flat-bottomed gate seat: The traditional gate valve often deposits in the groove at the bottom of the valve due to foreign objects such as stones, wood, cement, iron filings, and other debris after the pipe is washed with water. The bottom of the elastic seat-sealed gate valve adopts the same flat-bottom design as the water pipe machine, which is not easy to cause debris siltation and makes the fluid flow unimpeded.
Integral encapsulation: The disc adopts high-quality rubber for the overall inner and outer rubber. European first-class rubber vulcanization technology enables the vulcanized disc to ensure accurate geometric dimensions, and the rubber and ductile disc are connected firmly, not easy to fall off, and have good elastic memory . water
Precision casting valve body: The valve body adopts precision casting, and the precise geometric dimensions make the inside of the valve body without any finishing to ensure the sealing of the valve.
Features of dark-rod soft-seal gate valve:
The overall valve encapsulation is used to produce a deformation compensation effect to achieve a good sealing effect, overcome the poor sealing, water leakage and rust of the general gate valve, and save installation space more effectively. It can be widely used in tap water, sewage, construction, petroleum, chemical, It is used as a regulating and intercepting device on fluid pipelines such as food, medicine, textile, electric power, shipbuilding, metallurgy, energy systems. Our factory introduces European high-tech valve manufacturing technology to produce elastic seat-sealed gate valves, which are deformed by the overall encapsulation of the gate. The compensation effect achieves a good sealing effect and overcomes the phenomenon of poor sealing, water leakage and rust of general gate valves. It can be widely used as a regulating and intercepting device on fluid pipelines such as tap water, sewage, construction, petroleum, chemical industry, food, medicine, minor injuries, electric power, ships, metallurgy, and energy systems.
1. The gate adopts integral rubber encapsulation, and its good covering performance and precise geometric dimensions ensure reliable sealing and longevity.
2. Light weight: The valve body is made of ductile iron, which is light in weight and easy to install.
3. Flat-bottomed valve seat: The bottom is designed with the same flat-bottomed valve seat as the water pipe, which does not produce debris and makes the seal more reliable.
4. Corrosion resistance: The inner cavity is coated with non-toxic epoxy resin to prevent corrosion and rust. Not only can it be used for raw drinking, but also can be used in sewage systems.
5. Three &#;0&#; seal: The valve stem is sealed with three O-rings, with low friction resistance, light switch and no water leakage.
How to select the non rising-stem gate valve and rising-stem gate valve?
For oil and natural gas pipelines, single disc or double disc gate valves are used. If you need to clean the pipeline, use a single disc or double disc rising-stem gate valve with diversion holes.
For the transportation pipeline and storage equipment of refined oil, select single disc or double disc gate valve without diversion hole.
For oil and natural gas mining wellhead devices, single disc or double disc gate valves with dark rod floating valve seats and diversion holes are selected, most of which are API16A standards, and the pressure levels are API, API, API, API, API, API.
For pipelines with suspended particulate media, use knife-shaped plate gate valves.
The city gas transmission pipeline adopts single disc or double disc soft-sealed rising-stem gate valve.
For urban tap water projects, single disc or double disc rising-stem gate valve without diversion hole is used.
If you would like more information about this product, please feel free to contact us. Recommend other popular products for you: Adjustable Choke Valve Manufacturers, API 6A Gate Valve Manufacture, API 6A Gate Valve Manufacturer, API 6A Gate Valve Manufacturers, FC Gate Valve, Tree Cap, Wellhead Ball Screw Gate Valve Supply, API 6A Choke Valve, Drill Stem Safety Valves, Function Of Choke Valve In Oil And Gas, Gate Valve Hydraulic, Screw Gate Valve, Gate Valve Problems, Advantages And Applications Of Water-Sealed Gate Valves, API 6A Gate Valves Manufacturer, API 6A Valves Manufacturer, Master Valve Wellhead
Figure 1: Bolted bonnet gate valve
Selecting the right gate valve material is crucial in the gate valve selection process. Various materials are used for the gate valve's body and seal. The material selection depends primarily on the media type and design temperature. This article discusses the common materials used in gate valves and how to find the right one for each application.
Gate Valves
Gate valves are used in a wide range of applications, and they come in contact with diverse media. It is critical to consider the material used for valve construction to prevent premature valve failure and system delays during valve operation. Consider the following criteria to select the proper materials for a gate valve:
Gate valves are available in various materials, as discussed in the next section. Various organizations are committed to developing and maintaining standards for valves and materials in specific environments. For example, gate valves are specified by the American Petroleum Institute (API) and the National Association For Corrosion Engineers (NACE) for their suitability to work with heavy corrosive media.
The various materials used to construct gate valve body are discussed below.
Figure 2: PVC gate valve
In a PVC gate valve, the valve's three main components, namely, the handle, housing, and gate, are made of PVC.
PVC gate valves are a good low-cost solution for most flow control needs at home. These valves are durable and corrosion-resistant, hence widely used in aquatic environments. A few common applications are:
In applications where PVC gate valves would burst, it is a viable option to use gate valves made of metals or their alloys.
Brass can withstand more heat than PVC, making them an ideal choice for residential plumbing applications. Brass is extremely corrosion resistant, and the gate valves made of brass are ideal for manufacturing industries involving natural gas or potable water.
Figure 3: Stainless steel gate valve
Stainless steel is extremely durable and corrosion-resistant, hence used in marine and industrial applications. Some common applications are:
Figure 4: Bronze gate valve
Bronze has high lead content; hence the material is not used frequently for drinking water applications. Bronze is commonly used for fluid control in low-pressure manufacturing industries and works well with steam, air, and gas. The material is also used in HVAC and marine applications.
Figure 5: Cast iron gate valve
Cast iron is used for constructing gate valves in low-pressure and low-temperature applications. The material is a popular choice for gate valves in water, wastewater, heating, ventilation, and air-conditioning (HVAC) units. Cast iron gate valves are extremely cheap, yet sturdy; hence these valves are more suitable for underground applications than steel valves.
Figure 5: Cast steel gate valves used in industrial plants
Gate valve seats are available in two forms:
Read our chemical resistance guide article for more details on the compatibility of materials with different media.
Gate Valves
For more information, please visit Ductile Iron Gate Valve.