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Y type ball check valves’ work theory, construction feature, advantage

August 11, 2020

1. Overview of ball check valve:
Ball type check valve is widely used in petroleum, chemical and electric heating boilers and other devices. It is

fig.01-ball check valve drawing

mainly used to prevent the reverse flow of the medium in the pipeline and protect the safe operation of the equipment. It is an ideal non-return device for pipelines. However, the current common check valve structures include swing type and lift type. Because these common check valves have problems such as easy sticking, poor sealing, difficult to repair, and may cause serious shutdown when they close by themselves. The valve water hammer phenomenon, and the water hammer pressure far exceeds the system working pressure, so the system safety may be endangered. Therefore, in addition to meeting the basic requirements of flow, the design of the check valve is the most important thing is the size of the flow resistance, whether there is leakage or vortex, which is related to energy consumption, and at the same time affects the level of production cost and product competitiveness. This new ball check valve is designed based on the theory of reducing flow resistance and eliminating water hammer.
2. Working principle of ball check valve:
The ball check valve shown in Figure 1 includes a valve body, a valve seat 2, a valve cover 7, and a valve disc. The valve body is composed of a left valve body 5 and a right valve body 1. The right valve body is the medium inlet end, and the left valve body The body is the outlet end of the medium. The valve seat 2 is installed between the left valve body 5 and the right valve body 1. The valve disc is a ball 3, and the sealing surface of the valve seat 2 is a spherical surface that cooperates with the surface of the ball 3. The left valve body is composed of a fluid channel and a ball track. The centerline of the sphere track forms an acute angle with the centerline of the fluid channel, and the angle design of the acute angle is determined according to the flexible rise and fall of the valve flap 3 in the sphere track. An arc-shaped filter screen 6 is arranged at the intersecting line of the fluid channel and the sphere orbit. The arc-shaped filter screen 6 has the same curvature as the inner circular wall of the sphere orbit, so that the inner arc of the arc-shaped filter screen 6 and the inner circular wall of the sphere orbit are formed The integral inner cylindrical surface constitutes a smooth rolling passage for the valve flap 3, which does not affect the flow of the medium, and enables the valve flap 3 to roll flexibly. This valve uses media thrust and disc gravity to automatically control the rolling position of the ball in the ball track. When the medium flows in the forward direction, the media thrust pushes the disc to the upper end of the ball track. When the positive thrust of the medium disappears, the disc moves from the ball track. The upper end rolls off and fits the valve seat sealingly, which has the advantages of simple structure, the ball is not easy to be stuck in the ball track, the sealing reliability is good, and the water hammer is small.
3. Structural features of ball check valve:

fig.2-ball check valve 3D schematic

The ball check valve has no transmission parts in structure and has a free opening and closing structure, so there is no wear of the shaft and sleeve. The valve flap automatically rotates in the ball orbit, and the sealing surface is always updated, and there is no fixed wear point. The ball surface wears evenly during the working process, and always maintains a high shape accuracy. The use performance will not decrease with the passage of time, which improves the service life of the seal. The surface of the valve disc is lined with rubber, and the dimensional accuracy and surface roughness of the ball can be controlled by the rubber lined mold. The processing accuracy of the ball is reduced, and it can be reused, which reduces the cost of the disc. The surface rubber of the steel ball will elastically deform, can absorb and dampen vibration, and play a certain buffering effect. The low density of rubber makes the inertia of the disc movement small and the movement is sensitive. The sphere adopts a hollow structure and is light in weight, which reduces the impact force of the valve disc on the valve seat when it is closed. The inner diameter of the sphere track is designed to be larger than the pipe diameter of the corresponding flange, which increases the flow cross section, reduces the medium resistance and reduces the pressure. When the sealing structure is designed according to the corresponding flange, the working pressure is from vacuum to medium pressure. Under the premise of not being restricted by installation conditions, the ball check valve can be installed horizontally or vertically. Moreover, the valve is easy to maintain in the pipeline, and only needs to replace the lower disc.
4. Conclusion of ball check valve:
In accordance with DIN EN 12266 “Pressure Test of Valves” and corporate standards, the series of ball check valves have been inspected and tested. As a result of the test, the technical performance parameters fully meet the design requirements. The application of this valve improves the safety factor of other equipment on the pipeline, with low flow resistance, flexible opening and closing, and good sealing performance, which is welcomed by users. This valve is also equipped with a curved filter screen to purify the medium. One valve has multiple functions, meeting customers’ multi-functional requirements, and greatly reducing customer costs.

Ball check valve introduction

August 10, 2020

Check valves are also known as counterflow valves, check valves, back pressure valves, and one-way valves. This kind of valve is automatically opened and closed by the force generated by the flow of the medium itself in the pipeline, and belongs to an automatic valve.

Uses and characteristics of ball check valve:

ball check valve (9)

HQ44X single-ball micro-resistance ball check valve and HQ45X double-ball micro-resistance ball check valve all use rubber covered balls as the disc. Their principle is that under the action of the medium, they can roll back and forth on the slide in the valve body, thereby Play to open or close the valve. The main features of HQ44X single-ball micro-resistance ball check valve and HQ45X double-ball micro-resistance ball check valve are large flow, small flow resistance pressure loss, good sealing performance, silencing closure, and reduction of water hammer waves. It can be installed horizontally or vertically. The micro-resistance ball check valve can be used at the pump outlets of cold water, hot water, industrial and domestic sewage pipe networks to prevent the medium from flowing back. In order to prevent the medium from flowing back, check valves should be installed on equipment, devices and pipelines

Ball check valve is also called reverse valve, check valve, back pressure valve, one-way valve. This kind of valve is automatically opened and closed by the force generated by the flow of the medium itself in the pipeline, and belongs to an automatic valve. The check valve is used in the piping system, and its main function is to prevent the medium from flowing back, preventing the pump and its driving motor from reversing, and to discharge the medium in the container. Check valves can also be used to supply pipelines for auxiliary systems whose pressure may rise above the pressure of the main system.

Product advantages of ball check valve:
1. The fluid resistance is small. The ball check valve is the smallest fluid resistance of all valves. Even the reduced diameter ball valve has relatively small fluid resistance.

2. The check valve is opened and closed quickly and conveniently. As long as the valve stem rotates 90°, the ball valve completes the fully open or fully closed action, which is easy to achieve rapid opening and closing.

3. Good sealing performance. Spherical check valve seat sealing ring is generally made of elastic materials such as polytetrafluoroethylene, which is easy to ensure sealing, and the sealing force of the ball valve increases with the increase of medium pressure.

4. The valve stem is sealed reliably. The valve stem only rotates when the ball valve is opened and closed, so the packing seal of the valve stem is not easily damaged, and the sealing force of the reverse seal of the valve stem increases with the increase of medium pressure.

5. The opening and closing of the ball valve can only be rotated by 90°, so it is easy to realize automatic control and remote control. The ball valve can be equipped with pneumatic device, electric device, hydraulic device, gas-liquid linkage device or electro-hydraulic linkage device.

6. The spherical check valve channel is flat and smooth, and it is not easy to deposit media, and the pipeline can be ball-passed.

Introduction of Carbon steel lift check valve H41H-16C

August 10, 2020

H41H-16C carbon steel lift check valve (check valve) is also known as one-way valve or check valve. Its opening and

lift-swing-check-valve-2

closing parts are opened or closed by the flow and force of the medium, and its function is to prevent the medium in the pipeline from flowing back .
check valve can be divided into three types according to the structure: lift check valve, swing check valve and butterfly check valve. Lift check valves can be divided into two types: vertical and horizontal; swing check valves are divided into three types: single, double and multiple; butterfly check valves are straight-through. The above-mentioned check valves can be divided into threaded connection, flange connection, wafer type and welding in connection form.
Attention to the installation of H41H-16C carbon steel lift check valve:
1. Do not allow the check valve to 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 pipeline system.
2. When installing, pay attention to the direction of medium flow should be consistent with the direction of the arrow marked on the valve body.
3. Lifting vertical flap check valve should be installed on the vertical pipeline.
4. Lifting horizontal flap check valve should be installed on the horizontal pipeline.

The products of Tianjin Tanghai Valve Manufacturing Co., Ltd. are:
1. Lift check valve: materials include cast iron, cast steel, stainless steel, chromium molybdenum steel; pressure: 1.0-16Mpa; connection methods include threaded connection, flange connection, welding; nominal pass: DN25-1200
Such as: cast steel lift check valve H41H-16C; stainless steel lift check valve H41W-16P; water pump bottom valve H42W-10/H42H-16C/H42W-16P.
Silence check valve HC41T-10; Silent check valve H42T-10; Spherical check valve HQ41X-10; Vertical fluorine-lined check valve H42F-10; Fluorine-lined lift check valve H41F46-16C; Wafer Muffler check valve H71T-10; Welded check valve H61H/Y-160
2. Swing check valve: the materials are cast iron, cast steel, stainless steel, chromium molybdenum steel; pressure: 1.0-16Mpa; connection methods include threaded connection, flange connection, welding; nominal passage: DN25-1200
Such as: cast steel swing check valve H44H-16C; stainless steel swing check valve H44W-16P; cast iron swing check valve H44T-10; rubber flap swing check valve HC44X-10; threaded connection Swing check valve H14H-16C/H14W-16P/H14T-10, H74W/F-16P.
3. Butterfly check valve: the materials are cast iron, cast steel, stainless steel, chromium molybdenum steel; pressure: 1.0-16Mpa; connection methods include threaded connection, flange connection, welding; nominal diameter: DN25-1200
Such as: double disc butterfly check valve H76H-16C/H76W-16P; micro resistance slow closing check valve HH47H-16C/HH48H-16C/HH49H-16C

To ensure your requirements, please specify when ordering:
1. For new project users, please provide the model designed by the design institute, and for replacement parts users, please provide the product model used before
2. If there is no specific model, please provide: 1. Use medium and temperature; 2. Working pressure; 3. Transmission method; 4. Connection method; 5. Structure form;
6. Nominal diameter, etc.
To
H41H-16C carbon steel lift check valve model, performance parameters, structure size parameters, price and other details. (Note: All text, data, and pictures in this article are for reference only. If you need detailed parameters, please call Senpin Company. With professional technology, professional manufacturing, and professional services, Tanghai Valve is committed to meeting user expectations , Constantly improve service quality, keep improving, “Sincere Service” is the eternal theme of Senpin. If you need help, please contact our sales Harry Li.)

TH VALVE is one of the largest butterfly valve manufacturers in China, main products are butterfly valves, check valves. Our products use advanced manufacturing technology, and strictly conform to API, DIN, BS, EN, ISO, GB and other international standards. The main products are butterfly valves, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…), etc. Our products are widely used in various fields such as marine industry, shipbuilding, petrochemical, metallurgy, water treatment, fire fighting, water supply and drainage, etc. The company has won unanimous recognition and praise from customers with high quality and good reputation.

Introduction of cast steel lift swing check valve

August 5, 2020

1. Overview of Cast steel lift check valve:

The lift check valve is selected for the pipelines of various working conditions such as petroleum, chemical industry

lift swing check valve (2)

and thermal power plants with a nominal pressure of PN1.6～6.4MPa and a working temperature of -29～550℃. Applicable media are: water, oil, steam, etc.

2. Structural features of Cast steel lift check valve:

1. Exquisite selection of materials, in line with domestic and foreign standards, the highest quality of materials.

2. The sealing pair is advanced and reasonable. The sealing surface of the valve disc and the valve seat is made of iron-based alloy or Stellite cobalt-based cemented carbide. It has good wear resistance, high temperature resistance, corrosion resistance and scratch resistance. ,long lasting.

3. The products are designed and manufactured according to the national standard GB/T12235.

4. Various piping flange standards and flange sealing types can be used to meet various engineering needs and user requirements.

5. The valve body has a complete range of materials, and the gasket can be reasonably selected according to actual working conditions or user requirements, and can be suitable for various pressure, temperature and medium working conditions.

According to user requirements, check valves with different structures and connections can be designed and manufactured for use with various equipment.

H41H lift check valve: Do not allow the check valve to bear weight in the pipeline. Large-scale check valves should be independently supported to prevent them from being affected by the pressure produced by the pipeline system. When installing, pay attention to the direction of medium flow should be consistent with the arrow direction indicated by the valve body. Suitable for water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea and other media.

H41H, H41Y type PN16~PN100 lifting steel check valve is one of the important links in the production process regulation system. It is a valve that controls the one-way flow of the medium in the pipeline to prevent the medium from flowing back. It is widely used in purification equipment, petroleum, chemical industry, metallurgy, electric power, textile and other production processes.

Product features of lift check valve:

1. H41H and H41Y lift-type steel check valves have the advantages of simple structure, reliable action and convenient maintenance.

2. When the medium flows into the valve body from the direction indicated by the arrow of the valve body, the pressure of the medium acts on the valve flap to produce an upward thrust. When the medium thrust is greater than the weight of the valve flap, the valve opens. When the force of the medium pressure acting on the disc after the valve plus the weight of the disc itself is greater than the force of the pressure acting on the disc before the valve, the valve is closed to prevent the medium from flowing back.

Lift check valve refers to the valve that automatically opens and closes the valve flap depending on the flow of the medium itself to prevent the medium from flowing back, also known as check valve, one-way valve, reverse flow valve, and back pressure valve. Check valve is a kind of automatic valve, its main function is to prevent the back flow of the medium, prevent the pump and drive motor from reversing, and discharge the container medium. Check valves can also be used to supply pipelines for auxiliary systems whose pressure may rise above the system pressure. Check valves can be divided into swing check valves (rotating according to the center of gravity) and lift check valves (moving along the axis).

Check valves are also called check valves, check valves, reverse flow valves, and back pressure valves.

The function of the check valve is to only allow the medium to flow in one direction and prevent the reverse flow. Usually this kind of valve works automatically. Under the action of the fluid pressure flowing in one direction, the valve flap opens; when the fluid flows in the opposite direction, the fluid pressure and the self-coincidence of the valve flap act on the valve seat, thereby cutting off the flow. Among them, the internal thread check valve and the butterfly check valve belong to this type of valve.

It includes swing check valve and lift check valve. The swing check valve has a hinge mechanism and a valve flap like a door that rests freely on the inclined valve seat surface. In order to ensure that the valve clack can reach the proper position of the valve seat surface every time, the valve clack is designed in a hinge mechanism so that the valve clack has enough space for rotation and makes the valve clack really contact the valve seat. The valve disc can be made of metal, or inlaid with leather, rubber, or synthetic covering, depending on the performance requirements. When the swing check valve is fully opened, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively small. The valve disc of the lift check valve is seated on the sealing surface of the valve seat on the valve body. Except that the disc can be lifted and lowered freely, the rest of this valve is like a shut-off valve. The fluid pressure lifts the disc from the sealing surface of the valve seat, and the backflow of the medium causes the disc to fall back onto the seat and cut off the flow. According to the conditions of use, the valve disc can be an all-metal structure, or it can be in the form of a rubber pad or a rubber ring inlaid on the disc holder. Like a shut-off valve, the passage of fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is larger than that of the swing check valve, and the flow rate of the swing check valve is restricted Rarely.

Swash plate type non-impact check valve

August 5, 2020

“Swash plate check valve” generally refers to tilting disc swing check valve.

Chinese name: PXH44H-150LB swash plate type non-impact check valve

8 tilting-disc-swing-check-valve-3

Structure length: ASME B16.10
Product design press: ASME B16.34
Inspection and testing: API 598

PXH44H-150LB swash plate type non-impact check valve details:

1. Product overview:

It is a new type of check valve developed by combining our company’s many years of valve production technology with foreign advanced product design and development. Its main advantage is to overcome the impact and water hammer caused by the swing check valve and the lift type upper return valve under working conditions. Phenomenon, to achieve no impact operation.

2. Design specifications:

Flange size according to: ASME B16.5 GB HG SH

Pressure rating: Class 150, 300, 600 PN 2.0, 5.0, 10.0 MPa

3. Structural features:

The double eccentric valve flap gradually contacts the sealing surface when it is closed, so that it can work without impact and noise.

Micro-elastic metal seat with good sealing performance.

Butterfly valve disc design, fast, sensitive and long service life.

The swash plate structure makes the fluid channel streamlined, with low flow resistance and energy saving effect.

4. Materials for main parts:

code	valve body	valve flap	valve sealing/seat
P	CF8	CF8+STL	0Cr19Ni9	PTFE
R	CF8M	CF8M+STL	0Cr17Ni12Mo2
K	CF3	CF3+STL	00Cr19Ni11
J	CF3M	CF3M+STL	00Cr17Ni14Mo2
E	CN7M	CN7M+STL	20 alloy
C	WCB	WCB+13Cr	0Cr19Ni9
D	LCB	CF8+STL	0Cr19Ni9

5. Main properties:

Items	normal swing check valve	swash plate type non-impact check valve
Closing force	big	small（about 1/5～1/8 of the former）
compact force	big	None
sealing performance	as per API 598, leakages allowed	can realize no leakage
flow resistance	big（ξ=1.3～2.5）	small（ξ=0.18～0.6）
flow ability	small(Cv=76)	big(Cv=154～333)
weight	big	small（about 80% of former）

Wafer type double disc swing check valve introduction

August 4, 2020

Introduction of wafer type double wing check valve:

1. Product appication of wafer type double swing check valve:

double plate check valve body

H76H/, H77H wafer butterfly double flap check valve is used for pure pipelines and industrial, environmental protection, water treatment, high-rise building water supply and drainage pipelines to prevent the reverse flow of media.

2. Product Features of wafer type double swing check valve:

Small size, light weight, compact structure and convenient maintenance
The valve plate adopts a dual type, which can be quickly closed under the elastic force of the spring.
Due to the quick closing effect, the medium can be prevented from flowing back
The length of the valve body structure is small and the rigidity is good
Safe and convenient, can be used for horizontal and vertical installation

3. Implementation standards

Flange connection size: GB/T1724.1-98
Structure length: GB/T12221-1989, ISO5752-82

4. Performance parameters:

Working pressure: 0-4 Mpa
Temperature: -29-425°C
Applicable medium: Water, Oil, Steam, Nitric acid.

5. Material of Dual Plate Swing check valve Parts

PART NAME	Material
BODY	Cast Iron; Ductile Iron; Stainless Steel; Carbon steel
DISC / PLATE	Stainless Steel; Carbon steel; Bronze
SHAFT / STEM	Stainless Steel Monel; Stainless Steel Inconel
SEAT / LINING	NBR/EPDM/VITON
BOLTS	Carbon steel
NUTS	Stainless steel
SPRING	SS304/SS306

Tanghai Valve is the best manufacturer of wafer type double swing check valve in China. We produce the best quality products with competitive low prices. Main products: butterfly valve, lug type butterfly valve, wafer type butterfly valve, U-type butterfly valve, double flange butterfly valve, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…)

The principles and difference between one-way valve and check valve

August 4, 2020

One-way valve is sometimes called a check valve. One-way valve is a device in which fluid can only flow along the

double-wing-check-valve-3

water inlet, but the medium at the outlet cannot flow back. The function of the check valve is to prevent the medium in the pipeline from flowing back. So what is the difference between the two? What is their working principle? Now, Mr. Harry Li from Tanghai Valve will give you a detailed introduction.

The difference between one-way valve and check valve:

One-way valve is a control type One-way valve, and check valve is a non-control type One-way valve. That is: One-way valve is used to provide pressure, and its main function is to maintain pipeline pressure. Although the check valve can also provide this function, it is mainly used to control the return of the medium and does not require pressure. That is: One-way valve has a tendency to control, and check valve is purely natural.

One-way valve means that the fluid can only flow along the water inlet, but the medium at the outlet cannot flow back, commonly known as the One-way valve. One-way valve is a check valve. The installation position of a swing check valve is not restricted. It is usually installed in a horizontal pipeline, but it can also be installed in a vertical pipeline or a dumping pipeline. When installing a check valve, pay special attention to the flow direction of the medium. The normal flow direction of the medium should be consistent with the arrow direction indicated on the valve body, otherwise the normal flow of the medium will be blocked. The bottom valve should be installed at the bottom of the pump suction line. When the check valve is closed, water hammer pressure will be generated in the pipeline. In severe cases, it will cause damage to the valve, pipeline or equipment, especially for large-mouth pipelines or high-pressure pipelines. Therefore, it should cause high attention of the check valve selection. . The check valve is only a one-way opening and closing valve that prevents the backflow of fluid media on various pipelines or equipment.

all types of check valve and structures -code names-photos

1. One-way valve: It is a typical seat valve, One-way valve, also known as check valve or check valve. Used in hydraulic systems to prevent reverse flow of oil flow.

One-way valve has two types: straight type and right angle type. The straight-through One-way valve is installed on the pipeline with a threaded connection. Right-angle One-way valve has three forms: thread connection, plate connection and flange connection. The hydraulically controlled One-way valve is also called a lock valve or a pressure holding valve. It is the same as the One-way valve to prevent the reverse flow of oil. However, when the oil flow is required to flow in the reverse direction in the hydraulic circuit, the oil pressure can be controlled and the One-way valve can be opened so that the oil flow can flow in both directions. The hydraulically controlled One-way valve uses a tapered valve core, so the sealing performance is good. When the oil circuit is required to be closed, this valve can be used as a one-way locking of the oil circuit to maintain pressure. There are two types of hydraulically controlled One-way valve to control oil leakage: internal leakage and external leakage. The internal drain type can be used in the oil circuit with no back pressure at the oil flow reverse outlet; otherwise, the external drain type is required to reduce the control oil pressure.

2. Check valve is only one type of valve, it can be said that One-way valve is a kind of check valve. The check valve is only a one-way opening and closing valve that prevents the backflow of fluid media on various pipelines or equipment.

There are many types of check valves:

(1) Spring type: the liquid is from bottom to top, relying on the pressure to push up the valve flap controlled by the spring. After the pressure disappears, the spring force will press down the valve flap to seal the liquid back flow. Often used for check valves with small diameters.

(2) Gravity type: similar to the spring type, it relies on the self-gravity of the valve flap to close it to prevent backflow.

(3) Swing type: The liquid flows directly through the valve body, and the rotating disc on one side is opened by the pressure. After the pressure is lost, the disc relies on its own weight to return to the position, and the reverse liquid pressure closes the disc.

(4) Other One-way valve (check valve), such as sewage check valve.

The working principle of one-way valve:

The one-way valve only allows airflow to pass in one direction, and is completely closed in the opposite direction. After the air pressure is added to the left side, the air pressure acting on the valve core overcomes the spring force and friction force to open the valve core, and the air inlet and outlet are connected. The flow of airflow from left to right is called forward flow. In order to ensure a stable flow of air from the air inlet to the air outlet, a certain pressure difference should be maintained between the air inlet and outlet to keep the valve in the open position. If air pressure is added to the air outlet, the air cannot flow in and out, that is, the air flow cannot flow in the reverse direction.

The working principle of the check valve;

Check valve refers to the valve that automatically opens and closes the valve flap depending on the flow of the medium itself to prevent the medium from flowing back. It is also called check valve, one-way valve, reverse flow valve, and back pressure valve. Check valve is a kind of automatic valve, its main function is to prevent the back flow of the medium, prevent the pump and drive motor from reversing, and discharge the container medium. Check valves can also be used to supply pipelines for auxiliary systems whose pressure may rise above the system pressure. Check valves can be divided into swing check valves (rotating according to the center of gravity) and lift check valves (moving along the axis).

The function of this type of valve is to only allow the medium to flow in one direction, and to prevent the flow of direction. Usually this kind of valve works automatically. Under the action of the fluid pressure flowing in one direction, the valve flap opens; when the fluid flows in the opposite direction, the fluid pressure and the self-coincidence of the valve flap act on the valve seat, thereby cutting off the flow.

The difference between one-way valve and check valve

August 4, 2020

One-way valve means that the fluid can only flow along the water inlet, and the medium at the water outlet

double-wing-check-valve-3

cannot return. Used in hydraulic systems to prevent reverse flow of oil or pneumatic systems to prevent reverse flow of air. Check valve refers to a valve whose opening and closing parts are circular discs and rely on its own weight and medium pressure to generate actions to block the back flow of the medium. It is an automatic valve.

There are two types of check valves: straight-through and right-angle. The straight-through check valve is installed on the pipeline with a threaded connection. Right-angle check valves have three forms: threaded connection, plate connection and flange connection. Hydraulic control check valve is also called lock valve or pressure maintaining valve. It is the same as check valve to prevent reverse flow of oil. However, when the oil flow is required to flow in the reverse direction in the hydraulic circuit, the oil pressure can be controlled to open the one-way valve so that the oil flow can flow in both directions. The hydraulic control check valve adopts a conical valve core, so the sealing performance is good. When the oil circuit is required to be closed, this valve can be used as a one-way locking of the oil circuit to maintain pressure. There are two types of hydraulically controlled check valve to control oil leakage: internal leakage and external leakage. The internal drain type can be used in the oil circuit where the oil flow reverse outlet has no back pressure; otherwise, the external drain type is required to reduce the control oil pressure.

The check valve can also be used to supply the auxiliary system whose pressure may rise above the system pressure. Check valves can be divided into swing check valves (rotating according to the center of gravity) and lift check valves (moving along the axis). The function of this type of valve is to only allow the medium to flow in one direction and prevent the 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 flap opens; when the fluid flows in the opposite direction, the fluid pressure and the self-coincidence of the valve flap act on the valve seat, thereby cutting off the flow.

One-way valve is a directional control valve in which air flow can only flow in one direction but not in the reverse direction. Its working principle is the same as the hydraulic one-way valve. Compressed air enters from port P, overcomes the spring force and friction force to open the one-way valve port, and the compressed air flows from P to A; when there is no compressed air at port P, it will be under the action of spring force and remaining force of port A (cavity) ; The valve port is in the closed state, so that the air flow from A to P is blocked. The one-way valve is used in occasions where the air flow is not allowed to flow in the opposite direction. For example, when the air compressor is inflating the air tank, a one-way valve is set between the air compressor and the air tank to prevent the air tank when the air compressor stops working. The compressed air in the air flow is returned to the air compressor. One-way valves are often combined with throttle valves and sequence valves to form one-way throttle valves and one-way sequence valves.

Check valves have a wide range of uses, and there are many types. The following are the check valves commonly used in water supply and heating:

1. Spring type: the liquid is from bottom to top, and the valve clack controlled by the spring is pushed up by the pressure. After the pressure disappears, the spring force pushes down the valve clack to seal the liquid back flow. Often used for check valves with small diameters.

2. Gravity type: Similar to spring type, it is closed by the gravity of the valve disc to prevent backflow.

3. Swing type: The liquid flows directly through the valve body, and the rotating disc on one side is opened by the pressure. After the pressure is lost, the disc relies on its own weight to return to the position, and the reverse liquid pressure closes the disc.

4. Plastic diaphragm type: Both the shell and the diaphragm are plastic. The general shell is ABS, PE, PP, NYLON, PC. The diaphragm includes silicone resin, fluororesin, etc.

In general, the check valve and the check valve are basically the same thing, but there are some differences. The check valve is a controlled check valve, and the check valve is a non-controlled check valve. That is to say, the one-way valve is used to provide pressure, and its main function is to maintain pipeline pressure. Although the check valve can also provide this function, it is mainly used to control the return of the medium and does not require pressure.

The above is about the difference between check valve and check valve. In fact, a check valve is only one type of valve, and a oneway valve is only a type of check valve. It is only a one-way open-close valve that prevents backflow of fluid in various pipelines or equipment. Check valves have a wide range of uses.

What is double plate swing check valve

August 3, 2020

Main features of Double plate swing check valve:

double wing check valve (5)

Two valve plates are fixed on the valve body along a pivot axis, and two springs are installed on the butterfly plate above the sealing surface. Driven by the pressure of the medium flow, the spring is compressed to force the butterfly plate to open. When the medium flows back , The spring forces the valve to close. This kind of valve can be assembled on horizontal and vertical pipelines.

Design Features of Double plate check valve:
Design standard: API 594, API 6D, ASME B16.34, GB/T 12236
Good sealing performance
Small size and light weight
Wide application, flexible disc, fast closing
Valve plate closes quickly
Small closing impact

Product Range:
Body material: carbon steel, stainless steel, alloy steel
Caliber: 1/2″~60″(DN15~DN1500)
Pressure range: Class150~2500 (PN10~PN420)
Connection method: RF, RTJ, BW
Working temperature: -196℃~+560℃

TH VALVE is one of the largest double plate check valve manufacturers in China, main products are butterfly valves, check valves: butterfly valve, lug type butterfly valve, wafer type butterfly valve, U-type butterfly valve, double flange butterfly valve, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…)

What is a Single-disc swing check valve

August 3, 2020

Product details of Single-disc swing check valve:
Brand: THV

single disc swing check valve body

Type: TH-CKV-SDS
Material: Stainless steel, cast iron, etc.
Connection form: Wafer structure Butterfly type
Nominal diameter DN15-DN400 (mm)
Applicable medium: fresh water, sea water, steam, food, medicine —-
Form Butterfly Pressure Environment Normal Pressure Standard British Standard American Standard National Standard Flow Direction Two-way Drive Mode Manual Operating Temperature Normal Temperature Type (Channel Position) Straight-through

Applicable medium:
Fresh water, sea water, air, steam, food, medicine, and various oils, acids, alkalis, salts, etc.

Features of single disc swing check valve:
Long service life, reliable sealing performance and no frequent maintenance. The flow characteristic of the butterfly valve is 3 times that of the globe valve and 75% of the gate valve of the same specification. The butterfly valve can realize the switching and regulating function of the fluid in the pipeline. Compared with the gate valve and the stop valve, it has a better multifunctional type. The various choices of internal parts and elastic materials make butterfly valves widely used in the chemical industry.

The butterfly valve is light in weight and small in size. For example: the weight and volume of a 10″ butterfly valve are respectively 1/9 and 1/6 of a 10″ gate valve. Therefore, the butterfly valve is easy to install and can save the cost of the piping system. Compared with metal-sealed gate valves and globe valves, soft-sealed butterfly valves can achieve complete air tightness. The butterfly valve is easy to operate and can realize the opening and closing function within a 90° rotation range. The price of the butterfly valve of the same specification is about 35-40% of the price of the gate valve, and the installation cost of the butterfly valve is relatively low. The correctly installed butterfly valve has a certain degree of self-cleaning, and it is not easy to fail due to the stolen goods in the pipeline.

Note: The valve connecting flange size in this table conforms to BS4504 PN10, and the transmission connecting flange size conforms to ISO5211. In addition, it also meets the flange connection standards of other countries and the special connection sizes required by customers.

TH valve is one of the largest butterfly valve manufacturers in China, main products are butterfly valves, check valves.., Main products: butterfly valve, lug type butterfly valve, wafer type butterfly valve, U-type butterfly valve, double flange butterfly valve, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…)

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