Check Valve


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How does a check valve work?

Cracking pressure

A check valve requires a minimum upstream pressure (pressure differential between inlet and outlet) to open the valve and pass the media through it. This minimum upstream pressure at which the valve opens is called the check valve's ‘cracking pressure.’ The specific cracking pressure changes based on the valve design and size, so ensure that the system’s pressure can generate the cracking pressure of the chosen check valve(s).


Closing

If the upstream pressure falls below the cracking pressure or there is back pressure (flow attempting to move from the outlet to the inlet), the check valve will close. Typically, check valves have a gate, ball, diaphragm, or disc that is pressed against a seal to close the check valve. Gravity or spring can assist the closing process. As the inlet pressure decreases below the cracking pressure or there is backpressure, the valve closes by gravity, spring, and/or by using the backpressure.


Installation orientation

As a one-way valve only allows flow in one direction, it is crucial to know the correct installation orientation. Typically, an arrow on the valve’s housing indicates the flow direction. If there isn’t an arrow, examine the valve to ensure it is installed in the intended flow direction. If the valve is installed backward, media will not be able to move through the system, and the resulting pressure build-up can cause damage.


Normally open and normally closed check valves

A normally open check valve allows the medium to flow freely but shuts off the flow in case of backflow. A normally closed check valve prevents the flow of media through it until the cracking pressure builds up, at which point the valve opens.


Check valve types

Check valves operate differently depending on their design. The most common check valve is a spring-loaded in-line check valve; however, we will discuss multiple types below.


Spring-loaded in-line check valve

In-line spring-loaded check valves are common, easy to understand and have a simple design. Figure 2 shows a spring-loaded in-line check valve in the open and closed positions. The arrows indicate flow direction. When flow enters the input port of the valve, it should have enough pressure (force) to overcome the cracking pressure and the spring force. The pressure pushes the disc, opening the orifice and allowing flow to move through the valve. When the input pressure is no longer high enough or there is enough back pressure, the back pressure and spring push the disc against the orifice and seal the valve shut. The spring, along with the short travel distance for the disc, allows for a quick reaction time for closing. This valve design also prevents pressure surges in the line, preventing water hammer.


Common types of spring-loaded in-line check valves are also called:

nozzle check valves

poppet check valves

axial check valves

excess flow check valves

silent or quiet check valves

antiwater hammer check valves


They can be installed in a vertical or horizontal orientation. However, as they are in line with the system, they must be fully removed from the line to be inspected and/or maintained. A dual plate check valve has two spring-loaded plates mounted on a central pin. This design prevents slamming and water hammer effectively.


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Check Valve Details:

PART NAME

MATERIAL

BODY

ASTM A126 B

SEAT RING

ASTM B62 C83600

DISC

ASTM A126 B

DISC RING

ASTM B62 C83600

HINGE

ASTM A536 65-45-12

STEM

ASTM A276 410

BONNET

ASTM A126 B

LEVER

CARBON STEEL

WEIGHT

CAST IRON


We Offer Different check valves  

Swing check valve, also known as check valve or check valve, its role is to prevent the medium in the

pipeline flow back. Opening and closing parts on the medium flow and force to open or close, to prevent the medium back flow valve called check valve. Check valve belongs to the automatic valve class, mainly used for medium one-way flow on the pipeline, only allow medium to flow in one direction, to prevent accidents. This type of valve should be installed horizontally in the pipeline.


Standard

Design: EN558-1

Face to face: API609 / EN593 / EN558 / DIN3202 F6

Flange drilling: DIN2501 / ANSIB16.10 / EN1092 / DIN2531 / DIN2532 / DIN2533 / EN1092

Working temperature:0-100℃

Working pressure: PN10/PN16


Main Parts and Material:

Unit: mm

DN

H1

H2

D

L

100

460

109

220

127

150

530

143

285

140

200

570

182

340

152

250

660

219

400

165

300

715

244

455

178

350

750

283

505

190

400

785

312

565

216

450

890

344

615

222

500

920

381

670

229

600

995

451

780

267

700

1055

526

895

292

800

1135

581

1015

318

900

1190

643

1115

330

1000

1315

722

1230

410

1200

1505

840

1455

470

1400

1740

1150

1675

530

1600

1915

1305

1915

600

1800

2100

1425

2115

670

2000

2225

1580

2325

760

2200

2325

1710

2550

580

2400

2570

1880

2760

750

2600

2850

2010

2960

900


For other sizes not mentioned above, please contact us.We have right to change the data without further notice.


Here is the link to our product video:  


Our Capability

HAOZHIFENG manufactures and designs complete series of Valves according to DIN/BS/EN/API/ANSI/AWWA

/ASME/ Russian and other major standards.

-Gate Valves,

-Butterfly Valves,

-Check Valves,

-Y-Strainers

-Air Release Valves

-Globe Valves

-Fire Hydrant


The Valves supplied by SYI Pipelines are mainly used for adjusting water, steam, oil, gas, and natural gas in chemical industries, acid, alkali, and salt working pipelines. Sizes from 50-2000mm can meet full requirements from customers.


A group of highly experienced technical engineers are right here waiting for any of your request. Professional software used for design and test.


We are able to use most of the world-wide engineering software, including AUTO Cad, Pro Engineer, Solid Works and etc.


SYI is keeping on designing the series of valves for pursuing the better performance and easier operation.


New design and patterns could be developed based on customers’ requirement.



FAQs

What is a check valve?

A check valve is a unidirectional valve that passes fluid in one direction but prevents any flow in the opposite direction.


What is the purpose of a check valve?

The main purpose of a check valve in a system is to prevent backflow, which could damage equipment or contaminate media upstream.


What are common check valve problems?

Common check valve problems are noise, water hammer, vibration, reverse flow, sticking, leakage, and component wear/damage.


Will a check valve stop water hammer?

A check valve can prevent water hammer if it is fast-acting like a spring-actuated check valve. This prevents pressure surges, which create shock waves throughout the media.


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  • Haozhifeng® is a renowned name in the valve manufacturing industry. Established in 2003, our company has grown to become a leading producer of high-quality valves. Our product range includes butterfly valves, gate valves, Stainless Steel Valve with Anti-Corrosion Properties and heavy-duty stainless steel check valve for oil and gas pipelines. We take immense pride in our ability to develop innovative products that cater to the diverse needs of our clients.

  • When it comes to water treatment plants, various types of valves are used to ensure safe and efficient water supply. One of the most important valves is the Flanged Direct Flow Check Valve for Water Treatment Plants, which prevents backflow and protects the system from contamination. But not all check valves are created equal. If you're looking for a reliable and high-quality check valve, look no further than Check Valves from Haozhifeng®.

  • Haozhifeng® is a leading manufacturer of high-quality Direct Flow Check Valve for Industrial Use suitable for industrial use. With over ten years of production experience, we offer a diverse range of valves, including stainless steel, ductile iron, and aluminum casting. Our check valves are used in high-pressure applications and offer reliable performance to ensure smooth operations.

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Haozhifeng has been producing Check Valve for many years and is one of the professional high quality Check Valve manufacturers and Suppliers in China. We have our own factory.You can wholesale customized products from our factory. Products with cheap price or low price is of high quality. Customers are satisfied with our products and excellent service. We sincerely look forward to becoming your reliable long-term business partner!
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