Check valves

Check valve manufacturer

XinHui is a Check valves manufacturer, we supply check valves in cast and forged steel materials. Our valve factory in China specializes in the production of high temperature and high pressure check valves for the power station industry. Also a supplier of double plate wafer check valves, inclined plate check valves and non-shock check valves.

Check valve

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Check valves
API ASME Swash plate type check valve
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Check valves
Quick shut Evacuate steam pneumatic check valve
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Check valves
Single flap piston type check valve factory
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Check valves
Empty Exhaust Check Valve Factory
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Check valves
H42F4(F46) Fluorine lined check valve
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Check valves
H41H Lift Check Valve
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Check valves
H14W Internal Thread Swing Check Valve
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Check valves
BH664H Exhaust Check Valve

Check Valve Buyer's Guide

The selection of most check valves is based on a qualitative evaluation of small shock pressure or no shock closure and the required closing speed and its closing speed characteristics. When purchasing a check valve, it is necessary to provide a check valve with the supplier.

Complete information on valve operation

1. For high and medium pressure check valves below DN50mm, vertical lift check valves and straight-through lift check valves should be selected.

2. For low pressure check valves below DN50mm, butterfly check valves, vertical lift check valves and diaphragm check valves should be selected.

3. For high and medium pressure check valves with DN greater than 50mm and less than 600mm, swing check valves should be selected.

4. For medium and low pressure check valves with DN greater than 200mm and less than 1200mm, non-wear spherical check valves should be selected.

5. For low-pressure check valves with DN greater than 50mm and less than 2000mm, butterfly check valves and diaphragm check valves should be selected.

6. For the pipelines that require to close the pipeline with relatively small or no water hammer impact, the slow-closing swing check valve and the slow-closing butterfly check valve should be selected.

7. For the pump inlet pipeline, the bottom valve should be selected.

8. When the water pressure in front of the valve is small, swing, ball and shuttle check valves should be used

9. When the airtight performance after closing is strictly required, a check valve with a closing spring should be selected.

10. When it is required to weaken the closing water hammer, a quick-closing muffler check valve or a slow-closing check valve with a damping device should be selected.

11. The valve or valve core of the check valve should be able to close by itself under the action of gravity or spring force.

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Why choose XinHui check valve?

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All You Need to Know About Check valves

01

Introduce

what is a Check valve？

The check valve is also called a one-way valve or a check valve. The opening and closing part is a circular disc. It is a valve that relies on the pressure of the medium itself and the weight of the valve core to realize the opening and closing state to prevent the backflow of the medium. So as to protect the safety of the pipeline! It does not need human drive and belongs to automatic valve.

What is a Check valve used for?

The main function of the check valve is to prevent the backflow of the medium, the reverse rotation of the pump and the drive motor, and the discharge of the medium in the container. Not suitable for medium containing solid particles and high viscosity. By choosing different materials, it can be applied to various media such as water, steam, oil, nitric acid, acetic acid, strong oxidizing medium and urea.

02

Introduce

03

Introduce

how does a Check valve work？

Check valves can be mainly divided into: Swing check valves，Lift check valves；This type of valve works by allowing flow in one direction and preventing flow in the opposite direction. Usually this kind of valve works automatically. Under the action of the fluid pressure flowing in one direction, the valve opens, and when the fluid flows in the opposite direction, the fluid pressure and the self-coincidence of the valve disc are used. Acts on the valve seat, thereby shutting off flow. Among them, the check valve belongs to this type of valve, which includes swing check valve and lift check valve. Swing check valves have a hinged mechanism and a door-like disc that rests freely on the sloping seat surface. In order to ensure that the valve disc can reach the proper position of the valve seat surface every time, the valve disc is designed in the hinge mechanism, so that the valve disc has enough space to rotate and make the valve disc truly and comprehensively contact the valve seat. The check valve is often used as the bottom valve of the pumping device, which can prevent the backflow of water. The combined use of the stop valve and the globe valve can play the role of safety isolation, but the disadvantage is that the resistance is large and the sealing performance is poor when closed. Check valves may also be used on lines supplying auxiliary systems where pressure may rise above system pressure.

How to determine the size of the check valve？

Chatter, which occurs when the valve is oversized, is one of the most common causes of check valve failure. If the valve vibrates a lot (repeatedly opening and closing the valve), it can cause premature wear of internal parts, which can lead to spring failure, damage to the poppet, or deformation of the valve seat, all of which can affect how the valve seals back into flow. Pipe size and the need for maximum Cv (flow coefficient) are common ways to select a check valve. Unfortunately, this approach completely ignores the fact that the check valve is sensitive to flow conditions. It is important to remember that the size of the check valve should be based on the actual application, not the size of the pipe. The poppet needs to be stable against the internal stop in either the open or fully closed position; this will prevent chattering (chatter or excessive vibration) and therefore premature failure due to excessive wear of the internal parts. Properly sizing check valves minimizes the possibility of chattering. By understanding temperature, pressure, media, flow and viscosity, we can help determine the flow characteristics of a valve when it is in use. We want to ensure that the pressure drop across the valve is at least 1 psi, but it is better to choose a larger pressure to ensure the valve is in the fully open position. Round Valve Technology offers a wide variety of check valve product lines with various spring ranges and seal materials to suit a variety of applications.

Check valve diagram

This is a schematic diagram of the structure of the swing check valve, which is a one-way valve. When the liquid flows forward, the liquid pushes the valve disc and flows through the swing check valve. When the liquid flows in the reverse direction, the liquid closes the valve, and the liquid cannot pass through the swing check valve.

04

Introduce

05

Introduce

How to Install a Check valve？

1. Before installing the check valve, you must carefully check the appearance, brand, etc. of the check valve to see if it meets the relevant standards stipulated by the state, and the check valve should be tested for strength and tightness. After confirming that it is qualified, can be installed and used.

2. If the check valve is to be installed correctly, the installation height of the check valve, the inlet and outlet directions of the water flow, etc. must comply with the relevant installation specifications, and the flow direction of the internal medium should be the same as that marked on the check valve. The direction of the arrow is the same, as for the connection position, it must be tight and firm.

3. When installing the check valve, you should first observe the two ends of the check valve in detail, then find the water inlet port of the check valve, and then connect the water inlet port of the check valve and the water outlet port of the water pipe together. , When the water flows in from the inlet port of the check valve, the check valve will start to operate.

4. The water inlet port of the check valve is usually located at the lower position of the check valve, and the water outlet port of the check valve is generally located at the upper position of the check valve. When the water pressure of the water flowing into the check valve exceeds a certain value, the valve of the check valve will automatically open, and then water will flow out of the water outlet port of the check valve.

5. When the water pressure of the water flowing into the check valve is lower than a certain value, the phenomenon of backflow of water will occur in the check valve, and the valve of the check valve will also be automatically closed, and no water will flow out of the water outlet port. Through the above water flow phenomena, it can be detected whether the check valve is installed correctly.

Should the check valve be installed before or after the pump?

The check valve can be installed before and after the water pump. The check valve is installed in the water pump to fill the water pump once without pumping water, and the check valve is installed behind the water pump when the liquid level is higher than the water pump. When starting and stopping the water pump, it is not necessary to close the water outlet valve of the water pump, and control the water pump system to the parent to prevent backflow.

How far should the check valve be from the pump?

The check valve should be installed as far as possible from the pump, or at least 5 times the diameter of the pipe.

Check valve application scenarios

The check valve, also known as a one-way valve or a check valve, is used to prevent the backflow of the medium in the pipeline. The bottom valve of the water pump suction valve also belongs to the check valve category. Butterfly double flap check valve is suitable for high-rise building water supply pipeline networks, pipeline networks with certain chemical corrosive mediums, pipeline networks with limited installation space, and also suitable for sewage pipeline networks. The lift-type silent check valve is suitable for the pipeline network with high quality requirements of water supply and drainage projects; the pipeline network with relatively high pressure requirements (PN2.5Mpa); it can be installed at the outlet of the pump and is an economical and practical waterproof hammer check valve. The lift-type silencing check valve is suitable for water supply and drainage system and high-rise building pipe networks. It can be installed at the outlet of the pump. The structure is slightly modified. It can be used as a suction bottom valve, but it is not suitable for sewage pipe network. The horizontal check valve is suitable for submersible, drainage and sewage pumps, especially for sewage and sludge systems. Swing rubber check valve is suitable for domestic water pipe network; but not suitable for sewage with a lot of sediment Swing single flap check valve is suitable for water supply system, petroleum, chemical industry, metallurgy and other industrial sectors, and is most suitable for places with limited installation space.

06

Introduce

OEM & ODM XinHui Check valve Applications

Steam extraction check valve H664Y-recommended for power station industry

For different temperatures, the main material is made of carbon steel or high temperature steel, the sealing surface is surfacing with cemented carbide, and the sealing surface is matched; the sealing surface of the valve seat is inclined at a certain angle to reduce the closing time, reduce the impact, and protect the safety of the equipment itself and the pipeline; equipped with damping The heavy hammer can balance the dynamic moment of the closing part and prevent the occurrence of no hammer; the inner cavity adopts a streamlined design, which has a large flow capacity and reduces the valve resistance;

H41F4 F46 Fluorine lined check valve-recommended for chemical industry

H41F46 fluorine-lined check valve is suitable for various concentrations of aqua regia, sulfuric acid, hydrochloric acid, hydrofluoric acid and various organic acids, strong acids and strong oxidants at -50℃～150℃. FEP is also suitable for various concentrations of strong bases It is used on pipelines of organic solvents and other corrosive gases and liquid media.

H44TC ceramic check valve-recommended power plant industry

H44TC swing type ceramic check valve is used in the inlet and outlet gate of the dry ash system of the power plant, and can also be used in the non-return device of various medium pipelines such as dry ash, water slag, etc. The nominal pressure is 1.0MPa and 1.6MPa, and the suitable temperature is ≤200℃. After the valve is closed, it is completely sealed in any direction. The valve body and bonnet are made of WCB steel castings or stainless steel castings. The sealing surface adopts hard seal. The material port of the valve is fully circulated without obstruction, with strong wear resistance, good sealing performance, small starting load and less ash sticking and ash formation.

H44H swing check valve - recommended for petroleum industry

H44H swing check valve is designed and manufactured in strict accordance with GB12236 standard. The connection between pin shaft and valve disc adopts built-in structure, which has excellent performance and more reliable sealing. The products are widely used in pipelines of various working conditions such as petroleum, chemical, pharmaceutical, and electric power industries.

BH44H insulation check valve-recommended for the pharmaceutical industry

A metal jacket is welded between the flanges at both ends of the BH44H swing-type heat preservation flange check valve. The side and bottom of the check valve are equipped with a jacket connection port for the entry and exit of steam or heat transfer oil, thereby It has the heat preservation effect on the check valve and ensures the normal circulation of viscous medium. Mainly used in the system pipelines of chemical, petroleum, asphalt, pharmaceutical, metallurgy and other industries, the main function is to transport the medium that will solidify and easily crystallize at room temperature.

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Testimonials

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Check Valves: Ultimate Guide

Types of Check Valves

Swing check valve

The disc of the swing check valve is disc-shaped and rotates around the shaft of the valve seat passage. Because the passage in the valve is streamlined, the flow resistance is smaller than that of the lift check valve. It is suitable for large-diameter occasions with low flow rate and infrequent changes in flow, but it is not suitable for pulsating flow, and its sealing performance is not as good as that of lifting type.

The swing check valve is divided into three types: single-lobe type, double-lobe type and multi-half type. These three types are mainly divided according to the diameter of the valve.

Lifting check valve

A check valve whose disc slides along the vertical centerline of the valve body. Lifting check valves can only be installed on horizontal pipelines. For high-pressure small-diameter check valves, the disc can be made of balls…

The shape of the valve body of the lift check valve is the same as that of the globe valve (it can be used in common with the globe valve), so its fluid resistance coefficient is larger. Its structure is similar to the globe valve, and the valve body and disc are the same as the globe valve.

Disc check valve

A check valve in which the disc rotates around the pin in the valve seat. The disc check valve has a simple structure and can only be installed on the horizontal pipeline, and the sealing performance is poor.

Pipeline check valve

A valve in which the disc slides along the centerline of the valve body. Pipeline check valve is a new valve. It is small in size, light in weight and good in processing technology. It is one of the development directions of check valve. However, the fluid resistance coefficient is slightly larger than that of the swing check valve.

Compression check valve

This kind of valve is used as a valve for boiler feed water and steam cut-off. It has the comprehensive function of lift check valve and globe valve or angle valve.

What type of check valve is best?

There is no absolute answer to this, and the one that suits the actual working conditions of different industries is the best!

What causes a check valve to fail?

What causes a check valve to fail?

1. Reverse installation of check valve

2. Check valve selection or installation error, such as vertical installation of horizontal check valve;

3. The disc of the check valve is rusted and dead

4. The blockage of foreign bodies causes the valve disc to close loosely

5. The valve disc is broken or has blisters

When should the check valve be replaced?

Most check valves are designed with a welded one-piece seat at the narrow valve throat, usually set at a 30 degree angle. This design makes it nearly impossible to repair the seat surface using “off the shelf” machines and tools. In the past, the lack of equipment that could adequately perform repairs left end users with only one option to restore the integrity of the system—removal and replacement of valves. To reliably remove and replace check valve seats in a cost-effective manner, valve repair suppliers must use custom tools, procedures, and techniques. Using this special tool, craftsmen have successfully replaced the seats of many check valves ranging in size from 12″ NPS to 50″ NPS.

During this repair process, personnel typically:

Document “as is” condition and dimensions
Liquid Penetration Testing (LPT) on existing seat surfaces
Machine removes existing Alloy 21 case hardening
Carry out LPT of base metal (valve body)
Base metal repairs if needed
Install new alloy 21 case hardened
Machining new seat surfaces to OEM specifications
Liquid Penetration Testing of New Seat Surfaces
Reassemble the valve and “blue check” the seat surface to ensure 100% contact
Document critical valve dimensions “after repair”

These new technologies, along with traditional valve repair procedures, provide the end user with refurbished components that can be returned to OEM specifications in this critical application without the time and expense of a complete valve replacement.

As with all mechanical parts, routine maintenance and inspections are essential to keep these types of valves working properly. Most end users follow a well-planned maintenance schedule; however, it’s worth reviewing the elements of a successful plan:

Schedule routine inspections and records of valve condition.
Non-destructive testing of seat surfaces and base metal pressure-bearing components.
Seat surface condition is maintained through repair processes such as those described herein.
Refurbish or replace worn valve components found during inspection.

If these types of valves do need to be replaced, please contact the OEM to help select the best valve for the application; allow for rigging and restraint of existing piping before the valve is removed; and take the opportunity to make any configuration changes, to improve the accessibility of valve maintenance.

Do check valves hold pressure?

Although the check valve also has the function of maintaining the pressure of the pipeline, it is usually used in the occasion of controlling the backflow of the medium, and there is no great requirement for the pressure.

What comes first check valve or gate valve?

1. Install the check valve first and then the gate valve or butterfly valve

Advantages

It can protect the check valve, especially in parallel pumps, when one pump does not start, its outlet door is closed, and when the other pump starts, the impact force is borne by the gate valve or butterfly valve. After the check valve fails, the inlet and outlet valve isolation systems can be closed for repair.

Disadvantages

Who will protect the gate valve or the butterfly valve? There was a case where the disc of the butterfly valve was broken.

2. Install the gate valve or butterfly valve first and then install the check valve

Advantages

It can protect the butterfly valve or gate valve, and the impact force is borne by the check valve.

Disadvantages

Who will protect the check valve? The check valve is opened and closed by the pressure difference. If the pressure of the main pipe is high, it will be closed, and the pressure of the pump will be opened when the pressure of the pump is high. Affect the life of the check valve. And the check valve is broken, especially the

a parent control system, which needs to be shut down for repair.

Generally speaking, due to the frequent opening and closing of the check valve, the internal connection parts and sealing parts are prone to damage. In order to facilitate repairs and prevent the entire system from being shut down due to the failure of the check valve, from this point of view, the check valve The valve will be installed before the outlet gate valve or butterfly valve. Is this basically what you see?

What is the service life of the check valve?

Under normal use, guaranteed repair and maintenance, the service life of the water pipe check valve is 20-40 years!

The service life of check valves has always been a concern of users. The service life of check valves and other products mainly comes from the manufacturing process and raw materials, and partly from the use environment and maintenance.

In the design and manufacturing stage of the check valve, the manufacturer will check the performance of the product and the quality of its own brand as strictly as possible, so as to achieve good results in the design and manufacture of the check valve. Therefore, most of the check valves that can pass the factory qualification inspection stage are guaranteed to reach the normal service life. After the user purchases, the service life will be affected from the time of transportation. During transportation, if the check valve is improperly placed and damaged to a certain extent, the service life will naturally be shortened. Secondly, for the use environment of the check valve, if the use environment is poor and the maintenance is improper, the service life of the check

valve will be shortened accordingly.

The valve body of the check valve is also inevitably contaminated and corroded due to prolonged exposure. For the cleaning of its surface, like other valves, it can be cleaned with the appropriate medium, and after the cleaning is completed, a certain anti-rust oil or anti-fouling coating is applied to it.

Choose manufacturers with quality assurance, like our XinHui Industrial Valve Company. We promise to insist on quality assurance for your valve products!

How do I know if my check valve is working?

The check valve is automatic and will work properly when installed correctly! If the installation is wrong, if the check valve is broken, the disc will be broken and the medium will flow back. The reason why the valve disc is broken is: the pressure of the medium before and after the check valve is in a state of close to balance and mutual “saw”. Just shattered, we can tell the check valve has failed!

Will the check valve get stuck?

Yes, if there are many impurities in the pipeline medium, or if it is maintained for a long time, the check valve will be stuck! It is recommended to install a filter on the front to reduce jamming.