The Working Principle And Features of Cast Iron Gate Valve

 Cast iron gate valves are very common in our lives. But I bet you don't know much about them. This article will help you to understand their characteristics and how they work.

Cast Iron Gate Valve

The Features Of Cast Iron Gate Valve

1. Precision molded valve body. The valve body is precision molded, which, due to its precise geometry, does not require any fine machining inside the valve body, ensuring tightness.

2. Small opening and closing torque save opening and closing costs. When opening and closing the valve, the direction of movement of the spool is perpendicular to the direction of water flow, thus facilitating the opening and closing of the valve.

3. Integral rubber encapsulation. The valve's inner and outer rubber are all made of high-quality rubber. First-class European rubber vulcanization technology ensures that the vulcanized valve has precise geometry, a strong connection between the rubber and the plastic iron valve, and an elastic memory that prevents mold and mildew.

4. Low fluid resistance. The internal flow path of the butterfly valve body is straight, so the fluid does not change direction as it passes through the butterfly valve, resulting in low fluid resistance.

5. Flat bottom valve seat. In traditional valves, after flushing the pipe with water, foreign objects such as stones, wood, cement, iron pieces, and debris often accumulate in the grooves at the bottom of the valve and can cause leaks.

The resilient seat valve has the same flat bottom design as the plumbing machinery, which prevents contamination by debris and impedes the flow of liquid.

6. Lightweight. The valve body is made of high-quality ductile iron and is approximately 20-30% lighter than conventional valves. It is easy to install and maintain.

DIN Cast Iron Rising-Stem Gate Valve

 

The Working Principle Of Cast Iron Gate Valve

Cast iron gates are water retaining elements that directly bear water pressure. The gate frame is the supporting member around the gate plate and is also the chute for the up and down movement of the gate plate. The outer part of the chute is set in the second phase concrete of the gate pier and bottom of the gate, which transfers the water pressure borne by the gate plate evenly to the gate pier and bottom of the gate chamber.

The water-bearing surface around the gate frame and the water-backing surface around the gate frame are smooth and straight after mechanical processing, so that the combined surface, the water stop surface, and the movement chute are combined into one.

When the gate is opened and closed under the action of the opening and closing machine, the tightening ramp and frame chute ensure the longitudinal and transverse running trajectory of the gate. Under the dual action of water pressure and the tight closing tilt iron, the gate plate is ensured to run smoothly. The gate plate and frame chute are tightly fitted so that water is effectively stopped.

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The Function Of a Check Valve

Check valve is also called clack valve, one-way valve, or non-valve valve because it only allows fluid to flow in one direction. These industrial valves are automatically activated by the force generated by the flow of the medium in the pipeline and can be classified as automatic valves. The check valve is used in the pipeline system, and its main function is to prevent the backflow of the medium, prevent the pump and its generator from reversing, and prevent the backflow of the medium from the container. This check valve can also be used to replace the auxiliary system at which the pressure can increase above the pressure of the main system. If the fluid flows back and the check valve is not installed, a water hammer may occur. Water hammer often occurs, with excessive force, and it is easy to damage the pipeline or components. Check valves can be used in a variety of applications ranging from pipelines to gas export facilities.

Cast Iron check valve

What Is a Check Valve?

Check valves are usually installed in the pipeline to prevent backflow. A check valve is basically a one-way valve in which the flow can flow freely in one direction, but if the flow turns, the valve will be closed to protect the piping, other valves, pumps, etc. If the flow is diverted without a check valve installed, a water hammer may occur. Water hammer often occurs with extreme force and can easily damage pipes or components.

Precautions when choosing a check valve

When selecting a check valve, it is important to conduct a cost-benefit analysis of the specific system. Usually, the focus is on reducing costs while obtaining the lowest possible pressure loss, but for check valves, higher safety equals higher pressure loss. Therefore, in order to ensure the check valve protection system, each system needs to be evaluated separately, and factors such as the risk of water hammer, acceptable pressure loss, and the financial consequences of installing a check valve must be considered. Click here to get more information about us.

Check valve

Where are the check valves used?

Check valves can be used in many different applications. For example, they are usually placed on the outlet side of the pump to protect the pump from backflow. The centrifugal pump is the most common type of water pump. It is not self-priming, so a check valve is essential to keep the water in the pipeline. In addition, check valves are often used in HVAC systems (heating, ventilation, and air conditioning systems). For example, HVAC systems are used in large buildings, where the coolant is pumped many storeys up. The check valve is installed here to make sure that the coolant will not be flushed back.

All check valves are suitable for various applications such as gas and liquid pipelines, water and steam systems, cooling towers, water treatment, gas export facilities, product tank farms, gas storage, and Mining dehydration.

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Will Stainless Steel Valves Rust?

Many people think that the purchase of stainless steel valves will be able to avoid the trouble of rusting valves, but in fact, stainless steel valves are only in the rust prevention performance is better, but can not ensure that completely rust-free.

 

The main causes of rusting of stainless steel valves

API Stainless Steel Gate Valve

Whether stainless steel valves are rusty or not has a lot to do with the working environment.

1. manufacturers production technology, stainless steel valves are after special anti-rust treatment, if the manufacturer's technology is not up to scratch, anti-rust work is not done, then the use of stainless steel valve rust is very normal.

2. stainless steel valves if the selection of materials is unreasonable, such as manufacturers to save costs and choose cheap unqualified steel production stainless steel valves, then the use of the valve is relatively easy to rust. Therefore, we must choose good quality stainless steel valve products of large manufacturers.

3. stainless steel valve long-term use in a harsh environment, such as stainless steel valve long-term exposure to sun and rain, or contact with acid and alkaline solvents, then it is inevitable rust.

There are various reasons for stainless steel valves to rust, but the main reason can be attributed to internal and external factors, internal factors are the material, production technology, and other aspects of the cause, while external factors are caused by the environment.

Stainless steel ball valve product characteristics

Stainless Steel Gate Valve

1. the three-way ball core is divided into T and L type, long service life, large circulation capacity, low resistance

2. three-way ball valve in the structure of the integrated structure, 4-side valve seat sealing type, flange connectionless, high reliability, design to achieve lightweight

3. The ball valve is divided into single-acting and double-acting types, the single-acting type is characterized by the fact that the ball valve will be in the state required by the control system in the event of a power source failure. Ball valve according to its channel position can be divided into straight type, three-way type, and right-angle type. The latter two types of ball valves are used to distribute the medium and change the flow direction of the medium.

 

In short, there are various reasons that lead to rusting of stainless steel valves. These problems can actually be solved as long as the control is good. In the purchase of stainless steel valves, choose the products of large manufacturers, so as to ensure that stainless steel valves have better quality. There is also the daily use of the process of attention to strengthening the maintenance of stainless steel valves. We are a stainless steel ball valve manufacturer, please feel free to contact us if you need them.

Common Types Of Check Valves

A check valve is a valve whose switching parts are disc-shaped and rely on their own weight and medium pressure to produce the effect of stopping the medium from flowing back. It is an automatic valve, also known as a one-way valve, check valve, backflow valve, or isolation valve. The commonly used check valves are as follows.

Swing check valve

Swing check valves have a disc-shaped valve flap and rotate around the axis of the valve seat channel. Because the internal passage of the valve is streamlined, the flow resistance is higher than that of a lift check valve. Small size, suitable for medium, small diameter, low pressure, and large diameter pipeline (large diameter case flow rate is low and infrequent flow changes). Sealing performance is not as good as lifting type.

 1. Swing check valve is divided into three types: single valve, double valve, and multi-flap type. These three types are mainly divided according to the diameter of the valve. The purpose is to prevent the media from stopping or backflowing and to reduce the hydraulic shock. Single-valve swing check valves are usually used in medium diameter applications. When a single-valve swing check valve is used for large diameter pipelines, it is best to use a slow-closing check valve in order to reduce water hammer pressure. Double-flap swing check valves are suitable for medium and large-diameter pipelines. Buttress double-flap swing check valve, small structure, lightweight, is a fast developing check valve; multi-flap swing check valve is suitable for large diameter pipeline.

2. The installation position of the swing check valve is not restricted, it can be installed on horizontal, vertical, or inclined pipelines.

 

Lifting check valve

Both vertical and horizontal. The body shape of the lift check valve is the same as the globe valve, so its fluid resistance is larger. The valve flap slides along the vertical centerline of the valve body. When the medium flows downstream, the valve flap is opened by the thrust of the medium. When the medium stops flowing, the valve flap will fall on the valve seat due to self-trapping.

Vertical lift type check valve. The direction of the media inlet and outlet channels is the same as the direction of the valve seat channel, and its flow resistance is less than that of the straight-through type. A vertical lift check valve is installed in the vertical pipeline.

Vertical lift check valves can only be installed in horizontal piping. Restricted by the installation requirements, it is usually used in DN <50 small diameter occasions.

 

Butterfly check valve

The structure of the butterfly check valve is similar to the butterfly valve. The structure is simple, the flow resistance is small, and the water hammer pressure is small. Check valve, valve flap so that the valve flap rotates around the pin in the valve seat. Disc check valve structure is simple, can only be installed in the horizontal pipeline, poor sealing performance.

 

Diaphragm type check valve

There are a variety of structural forms, all using the diaphragm as the opening and closing parts, due to its good water hammer performance, simple structure, low cost, in recent years the development of faster. But the diaphragm checks valve temperature and pressure by the diaphragm material restrictions.

The diaphragm check valve is suitable for easy to produce water strikes on the pipeline, the diaphragm can well eliminate the water strikes generated by the media backflow, it is generally used in low-pressure room temperature pipeline, especially for water pipelines, the general medium working temperature between -12 - 120 ℃, working pressure <1.6MPa, but the diaphragm check valve can be larger diameter, DN can reach a maximum of 2000mm or more.

 

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Ball Valve vs Gate Valve

Choosing the right valve can determine the success or failure of the system. In today's market, with so many types of valves, it may be difficult to find the most ideal valve for your application.

The main difference between the ball valve and gate valve

Ball valves are also called "shut-off valves." Ball valves are the only way to immediately shut off the flow of water. The gate valve cannot be turned immediately. Except for three-way ball valves, machined stops can prevent most ball valves from moving more than 90 degrees.

Cast iron high-temperature ball valve

Gate valves usually have a round knob, which you can turn to control the flow of water. This raises or lowers an internal gate to stop or start the water. The gate valve provides control over the flow pressure, rather than simply closing or opening it. Gate valves provide users with greater flow and pressure control than ball valves, but they do not provide users with the option to stop the flow immediately. For those who wish to use gate valves but are concerned about corrosion, stainless steel gate valves are incredibly flexible and are not more susceptible to corrosion than ball valves.

DIN cast iron resilient bolted stem gate valve

Before asking the question "Is a ball valve better than a gate valve", we need to determine the key difference between the two. The first thing to remember is that they all have essentially the same function, which is why they are so similar.

The main difference between ball valves and gate valves lies in the quality of their structure and the way they are marked. When the gate valve is opened, the circular or rectangular gate is lifted from the fluid passage, while the ball valve has a rod and a horizontally rotating ball. This is why ball valves are often called rotary valves.

The gate valve has a sealing surface that separates the gate plate and the valve seat. Therefore, they are usually used when a straight-line flow of fluid and minimal restriction are required. Because the ball valve is a form of the quarter-turn valve, their functions are different. They use hollow balls, both perforated and rotated to control the flow. When the ball hole is consistent with the flow, the valve opens. When the valve handle rotates 90 degrees, it closes, and the handle lies flat. It is horizontal to the flow when it is opened, and perpendicular to the flow when it is closed. This makes it easy to visually confirm the state of the valve.

Are better ball valves than gate valves?

The advantage of ball valves is that their seals are tighter, so they are better at avoiding leakage than gate valves. This is due to its 100% shut-off characteristics. In addition, they are easier to use than gate valves, and have a lower failure rate and a longer service life.

The durability of the ball valve makes it ideal for closed applications. They always perform well after multiple cycles, are reliable, and can be safely shut down even if they are not used for a long time. For these reasons, they are generally preferred over gate valves and globe valves.

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Why Use a Ball Valve Instead of a Gate Valve?

There are many different types of valves on the market today, and it is difficult to decide which valve is most suitable for your application. In this article, we will discuss the advantages of ball valves and gate valves.

Choosing the best valve can make or break your system. Both ball valves and gate valves are used to limit and control flow. However, which gives better longevity and leak prevention though? Read on to find out.

API6D Cast Steel Ball Valve 150#

What is the main difference between the ball valve and the gate valve?

The ball valve and the gate valve basically have the same function. However, their structural characteristics are obviously different. Ball valves have a stem and ball, which turn horizontally, and are commonly referred to as 'rotational' valves. They are most suitable for applications that require on/off control without pressure drop.

Gate valves open by lifting the circular or rectangular gate (or wedge gate) out of the path of the fluid. The sealing surface between the gate and the valve seat is flat, so when a straight flow of fluid and minimum restriction is required, a gate valve is usually used.

How does the ball valve work?

The ball valve is designed with a ball inside the valve. A ball valve is a form of quarter-turn valve that uses a hollow, perforated, and rotating ball (called a 'floating ball') to control the flow through it. When the ball hole is consistent with the fluid, the valve opens; when the ball hole is rotated at a 90-degree angle by the valve handle, the valve closes. When the handle is opened, the handle lies flat in alignment with the flow, and perpendicular to the fluid when closed, which is convenient for visually confirming the state of the valve.

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API Stainless Steel Ball Valve Casting

Which is better, ball valve or gate valve?

The ball valve is durable, has good performance after multiple cycles, and is reliable, and can be safely closed even after a long period of disuse. These characteristics make it an excellent choice for shut-off applications and are usually the first choice for gate and globe valves. In other words, they do lack fine control in throttling applications.

Although ball valves tend to cost slightly more than gate valves of the same quality, the smallest savings are not worth the potential problems that are likely to follow. In addition, ball valves have a tighter seal and are therefore much less prone to leakage than gate valves because of their 100 percent shut-off characteristics. Ball valves have a longer life, a lower rate of failure, and are easier to use than gate valves. Please feel free to contact us if you need or want to know about our products.

Structural Characteristics of Welded Ball Valves

Keep reading for more information about the structural characteristics of welded ball valves.

 

1. The design of frame shaft fixed ball of welded ball valve

 

The balls of ball valves can be divided into two kinds: fixed balls and floating balls. Domestic products generally are in the floating ball structure, the ball being tightly pressed on the sealing surface of the outlet end under the pressure of the media to reach the purpose of the seal. Once the inlet and outlet pressure difference of the valve body is large, it is often very difficult to open the valve because of the large torque. Welded ball valves adopt high-strength forge steel for stems, rotating smoothly and being supported by the stainless steel bearings coated with PTFE.

 

Since the pivot-supported stems can absorb the thrust generated by the pressure of the pipeline media and can reduce the friction between the valve balls and the valve seats, the torque operating the concave door is still very small even under the full pressure difference condition and the ball valves still switch freely.

 

2. Structure of welded ball valve

 

The valve body of the ball valve is produced by welding six partially forged shells after assembly. The structure is compact and the whole ball valve is integrated. At present, the large-caliber ball valves used in production are mostly split three-piece structures, and each part is connected by bolts. Compared with the three-piece ball valve, under the same strength, the wall thickness of the welded ball valve forge piece can be made to be very thin, the valve weight can be reduced by a quarter, and the resistance to pipeline bending and extrusion is enhanced.

 

3. The valve stem and secondary valve seat seals of welded ball valves

 

The sealing material PFFE in the upper area of the valve stem of the welded ball valve is a low-friction and aging-resistant material with long service life. The valve stem of welded ball valve is also equipped with a sealing grease injection system. Even if foreign matter enters the ball valve seat and damages the sealing surface, it can still be injected with special sealing grease through the secondary valve seat to maintain the seal. Conventional ball valves do not have a sealing grease injection structure. Once the sealing surface is damaged and internal leakage occurs, we can only replace the entire ball valve.

                                              

4. Design of rotary valve seat of welded ball valve

 

When the ball valve is nearly being fully closed or just opened, the narrow point between the ball valve and the valve seat is scoured at high speed due to the fluid being throttled into high-speed turbulent flow, which becomes the most severely worn area of the seal of the valve seat. The valve seat upstream and downstream of the welded ball valve is rotated 15 degrees by the paddles on the valve ball so that the entire sealing surface of the valve seat is washed by fluid in turn, and the same part is washed again after the valve is opened or closed 12 times. The wear of the entire valve seat remains the same and the working life is greatly extended.

 

5. Pressure release device of welded ball valve

 

Automatic Internal Pressure Relief of the Valve Cavity and Pressure Relief of the Double Block Mid-cavity

Although ball valves have the up and down double valve seats partition seal, it is unavoidable that the valve seats may be damaged during the long-time operation. When the valves are in a close state, a certain internal leakage may occur on the upper valve seats, causing the media to leak out to enter the ball mid-cavities. The specially designed down valve seats can effectively avoid the overpressure of ball mid-cavities. Once the pressure of the valve chambers exceeds that of the down valve seats about 138Kpa, it will push away the down valve seats from the balls to release the pressure to the down pipelines. The ball valves are installed with pressure tubes that are connected to the mid-cavities and lead to the ground. Regardless of the valves are fully open or fully closed, we can open the valve cavities and shut off valves to release the mid-cavity pressure. The sealing performance of the valve seat can also be tested by releasing the mid-cavity pressure.

 

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What Are the Commonly Used Check Valves?

Check valve is also called one-way valve or check valve, its function is to prevent the medium in the pipeline from flowing back. The bottom valve of the pump to close the water is also a check valve.

The valve that opens or closes on its own by the flow and force of the medium to prevent the medium from flowing back is called a check valve. Check valves belong to the category of automatic valves, which are mainly used in pipelines where the medium flows in one direction, and only allow the medium to flow in one direction to prevent accidents.

Cast iron check valves are divided into three types: lift check valves, swing and lift check valves and butterfly check valves. Lift check valves can be divided into two types: vertical check valves and horizontal check valves. Swing check valves are divided into three types: single-leaf check valve, double-leaf check valve, and multi-leaf check valve. The butterfly check valve is a straight-through check valve. The above-mentioned check valves can be divided into three types in connection form: threaded check valve, flanged check valve, and welded check valve.

The installation of the check valve should pay attention to the following: 1. Do not make the check valve bear weight in the pipeline, and the large check valve should be independently supported so that it is not affected by the pressure generated by the piping system. 2. When installing, pay attention to the direction of medium flow should be consistent with the arrow direction of the valve body. 3. Lifting vertical flap check valve should be installed on the vertical pipeline. 4. Lifting the horizontal flap check valve should be installed on the horizontal pipeline.

Nominal pressure or pressure level of check valve: PN1.0-16.0MPa, ANSICLASS150-900, JIS10-20K Nominal diameter or caliber: DN15～900, NPS1/4～36 Connection method: flange, butt welding, thread, bearing Suitable temperature for plug welding: -196℃～540℃ Valve body material: WCB, ZG1Cr18Ni9Ti, ZG1Cr18Ni12Mo2Ti, CF8 (304), CF3 (304L), CF8M (316), CF3M (316L), Ti. Different materials are selected, and the check valve can be applied to various media such as water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea, etc.

Use of wafer check valve

The check valve is installed in the pipeline system, and its main function is to prevent the medium from flowing back. The check valve is an automatic valve that depends on the pressure of the medium to open and close. The wafer check valve is suitable for various pipelines with nominal pressure PN1.0MPa~42.0MPa, Class150~25000; nominal diameter DN15~1200mm, NPS1/2~48; working temperature -196~540℃, used to prevent The medium flows back. By selecting different materials, it can be applied to a variety of media such as water, steam, oil, nitric acid, acetic acid, strong oxidizing media, and uric acid.

The main material of the wafer check valve

There are carbon steel, low-temperature steel, duplex steel (F51/F55), titanium alloy, aluminum bronze, INCONEL, SS304, SS304L, SS316, SS316L, chromium-molybdenum steel, Monel (400/500), 20# alloy, Hastelloy, and other metal materials. The use and structural characteristics of the wafer check valve

Standards and specifications of wafer check valve

1. Design and manufacturing: API594, API6D, JB/T8937, JB/T3595,

2. Structure length: API594, API6D, DIN3202, JB/T8937, ANSI/ASMEB16.10

3. Pressure and temperature rating: ANSIB16.34, DIN2401, GB/T9124, HG20604, HG20625, SH3406, JB/T74

4. Test and inspection: API598, JB/T9092, GB/T13927

5. Piping flange: JB/T74~90, GB/T9112-9124, HG20592~20635, SH3406, ANSI/ASMEB16.5, DIN2543-2548, GB/T13402, API605, ASMEB16.47

The structural characteristics of the wafer check valve

1. The structure length is short, and its structure length is only 1/4~1/8 of the traditional flange check valve

2. Small size and lightweight, its weight is only 1/4~1/20 of the traditional flange check valve

3. The valve flap closes quickly and the water hammer pressure is small

4. Both horizontal pipes and vertical pipes can be used, easy to install

5. Unobstructed flow path and low fluid resistance

6. Sensitive action and good sealing performance

7. The disc has a short stroke and a small closing impact

8. The overall structure is simple and compact, and the appearance is beautiful

9. Long service life and reliable performance

The role of the check valve in the pump water supply system is to prevent the impact of the high-pressure water backflow on the pump impeller. When the system is running for some reason, when the pump suddenly stops running, the pressure in the pump disappears, and the high-pressure water connected to the outlet of the pump will flow back to the pump in the reverse direction. When the pump outlet is equipped with a check valve, it will be closed immediately to prevent the high-pressure water from flowing back to the pump.

The cast steel check valve is an automatic valve whose main function is to prevent the backflow of the medium, prevent the pump and drive motor from reversing, and release the container medium. Check valves can also be used to supply pipelines for auxiliary systems whose pressure may rise above the system pressure. The main function of the check valve is to prevent the medium in the pipeline from flowing back. The opening and closing parts are opened or closed by themselves by the force of the flowing medium. The check valve is only used in the pipeline where the medium flows in one direction to prevent the medium from returning to prevent accidents. We are a check valve manufacturer. If you are interested in our products, please contact us now!