valve manufacturer Archives

What is the difference between lining and vulcanized valve seat?

September 23, 2020

There are three types of rubber seat. One is a soft seat, which can be installed and removed at will. It is elastic; the other is a backrest seat, which is a hard seat. The seat is knocked into the valve by external force. The body, but it can also be disassembled, which is much more laborious than the disassembly of the soft seat; the third type is the vulcanized seat, which uses high temperature vulcanization to fix the seat to the valve body, so the vulcanized seat is sometimes called a fixed liner.
D71J is a rubber-lined valve cavity and butterfly plate are lined with rubber, D71X only the sealing surface is rubber
D71J rubber lining is that the valve body and disc plate are all covered with rubber. This is generally used for

Double flange butterfly valve (10)

corrosive media.
And D71X means rubber seal. It’s just the soft seal we are talking about. This general medium takes a lot of water. This price is also much cheaper.
The rubber lining in the rubber lining butterfly valve is to use high temperature to vulcanize the rubber and the valve body at high temperature. It has very high corrosion resistance and is generally used to control some corrosive fluids with strong acid and alkali.
The rubber butterfly valve is a butterfly valve whose seal is a rubber seal, which is generally called a valve seat, and is separately installed into a whole.
At normal temperature, the abrasion resistance of natural soft rubber is much better than that of nitrile rubber, but their high temperature resistance is the highest limit within 80 degrees, and it is not suitable for use if it exceeds 80 degrees.
The difference between fully lined butterfly valve and half lined butterfly valve:

U type flange butterfly valve (9)

1. Semi-lined butterfly valve means: the butterfly valve is not lined with rubber, and the place where the butterfly valve is connected to the valve body is lined with rubber;
2. Fully lined butterfly valve means: the butterfly plate of the butterfly valve and the part connected with the valve body are lined with rubber.
The difference between rubber lined butterfly valve, fluorine lined butterfly valve and plastic lined butterfly valve: rubber lined butterfly valve and fluorine lined butterfly valve are only one kind of plastic lined butterfly valve.
The sealing materials in the rubber-lined butterfly valve are:
Hard rubber NR applicable temperature: -10℃~85℃,
Suitable temperature of soft rubber BR: -10℃~85℃,
Suitable temperature of butyl rubber IIR: -10℃~120℃,
Applicable temperature of neoprene CR: -10℃~105℃;

The sealing materials in the fluorine-lined butterfly valve are:
Polyperfluoroethylene FEP (F46) operating temperature: -85℃~150℃,
Polytetrachloroethylene PTFE (F4) operating temperature: -200℃~180℃,
Polytrifluoroethylene PCTEF (F3) operating temperature: -195℃~120℃,
Polypropylene: RPP operating temperature: -14℃~80℃,
Polyvinyl chloride: rigid) PVC service temperature: 0℃-55℃,
Polyvinylidene chloride PVDF (F2) operating temperature: -70℃~100℃,
Polyolefin: PO Operating temperature: -58℃~80℃.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

The role and classification of valves

September 18, 2020

Valves have many functions. Different valves should be selected for different functions. Different types of valves have

U-type-flange-butterfly-valve-2

different structures. These functions are all means to effectively control the process and ensure safety. Valves are generally divided into automatic valves and drive valves. Automatic valves (such as safety valves, pressure reducing valves, steam traps, check valves) rely on changes in the pressure of the device or pipeline to achieve the purpose of opening and closing. Driving valves (gate valves, globe valves, ball valves, butterfly valves, etc.) rely on driving devices (manual, electric, hydraulic, pneumatic, etc.) to adjust the pressure, flow and direction of the medium in the pipeline. Due to the different pressure, temperature, flow rate and physical and chemical properties of the medium, the control requirements and use requirements of the device and piping system are also different, so the role of the valve is also different.
Classified by valve function:
Cut-off valve: The cut-off valve is also called a closed-circuit valve. Its function is to connect or cut off the medium in the pipeline. Block valves include gate valves, globe valves, plug valves, ball valves, butterfly valves and diaphragm

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

valves.
Regulating valve: Regulating valves include regulating valves, throttle valves and pressure reducing valves, whose function is to regulate the pressure and flow of the medium.
Check valve: 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.
Safety valve: The function of safety valves is to prevent the pressure of the medium in the pipeline or device from exceeding the specified value, so as to achieve the purpose of safety protection.
Diversion valve: Diversion valves include various distribution valves and traps, etc., whose function is to distribute, separate or mix the medium in the pipeline.
Exhaust valve: Exhaust valve is an indispensable auxiliary component in the pipeline system. It is often installed at high points or elbows to remove excess gas in the pipeline, improve the efficiency of pipeline use and reduce energy consumption.
The role of the valve: (cut-off, adjustment, check, safety)
1. Cut-off function An important function of the valve is the cut-off function. It is to cut off (shut off) the fluid in the pipeline to prevent it from circulating. Generally, the valves of various pipelines mainly play a cut-off role. To
2. Regulation function Another important function of the valve is to adjust the flow rate. According to the working conditions or use requirements, adjust the media flow, temperature, pressure, liquid level and other parameters in the pipeline. The control of this flow depends on the valve opening. To adjust the size of the degree. [Electric regulating ball valve Electric regulating butterfly valve Pneumatic regulating ball valve Pneumatic regulating butterfly valve]
3. Non-reverse function Some pipelines require the medium to flow in one direction, and no reverse flow or backflow is allowed. This requires the use of non-reverse valves (or one-way valves). It refers to a valve that automatically opens and closes the valve flaps depending on the flow of the medium itself to prevent the medium from flowing back. It is an automatic valve. Its main function is to prevent the medium from flowing back, prevent the pump and drive motor from reversing, and the container medium. put.
4. Safety function In order to prevent explosion accidents when the fluid pressure in the high-pressure container exceeds the pressure limit of the container when the pressure is too high, a valve that can automatically release pressure at a certain pressure is installed on the container, which is generally called a safety valve. For example, boilers, compressed air storage tanks and some high-pressure reactors are equipped with safety valves. This valve plays a role in ensuring safety.
5. Other functions In addition to the above four functions, the valve also has some functions, such as stabilizing the pressure of the system; reducing the high pressure in front of the valve to a lower pressure reducing effect, and releasing the pressure by venting to discharge sewage The function of sewage discharge; the sampling function of sampling for analysis and observation; and the backflow function of returning part of the fluid to the previous process. There are also steering valves (three-way valve, four-way valve, etc.) that transfer fluid to another pipeline.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

The difference of cryogenic valve and ordinary temperature valve

September 17, 2020

Cryogenic valves, as the name implies, are valves that can work in cryogenic and cryogenic conditions. The operating temperature is demarcated. Valves with operating temperatures below -40°C are usually called cryogenic valves, which are mainly used for gas liquefaction, For separation, transportation and storage equipment, the operating temperature can reach below -270℃. Currently, there are butterfly valves, check valves, gate valves, globe valves, ball valves, and throttle valves.

In recent years, ultra-low temperature valves have been used more and more widely, and they are one of the

lug type butterfly valve, ductile iron, center lined,

indispensable important equipment in petrochemical, air separation, natural gas and other industries. The working medium is not only low in temperature, but most of them are toxic, or flammable and explosive. , And strong permeability, so it determines many special requirements for valve materials and design. It is not only required to work normally at the set temperature, but also to ensure the working performance at room temperature.

Compared with the normal temperature valve, the low temperature valve has a higher packing part and uses an extended stem. Its purpose is to reduce the heat transferred from the outside into the device; to ensure that the temperature of the stuffing box is above 0℃, so that the stuffing can work normally; to prevent the valve stem and the upper part of the valve cover at the stuffing box part from being too cold The parts are frosted or frozen.

The design of the long-neck bonnet is mainly the design of the neck length L. L refers to the distance from the bottom of the stuffing box to the upper surface of the upper sealing seat. It is related to the thermal conductivity of the material, the thermal conductivity area, the surface heat dissipation coefficient, and the heat dissipation area. , The calculation is relatively cumbersome, and it is generally obtained by experimental methods.

Ferritic stainless steel can be used when the temperature is higher than -100℃, austenitic stainless steel can be used when the temperature is lower than -100℃, copper alloy or aluminum alloy can be used for low pressure and small diameter valves, and the valve body should be able to withstand temperature changes sufficiently. The expansion and contraction, and the structure of the valve seat part will not be permanently deformed due to temperature changes.

Valve installation instructions and process precautions

September 17, 2020

Valve is a kind of mechanical product that is widely used in the construction of national economy. In the current market, the more commonly used valve types are butterfly valves, check valves, ball valves, globe valves, gate valves and regulating valves. For the correct installation method of the valve, the user should understand the following introduction.

ductile iron, DI, butterfly valve, manufacturer, center line, TH valve

1. Valve installation
Valves should generally be positioned before pipeline installation. The piping should be natural, and the position should not be hard to avoid leaving pre-stress. During installation, it is recommended to install with a lifting ring. When installing with a chain, pay attention to protective measures for the outer coating of the valve. When the valve is equipped with a bracket or transmission mechanism, the sling should be fixed on the valve hoist ring, and the sling should not be placed on the transmission mechanism; the sling or hoisting chain should not squeeze the external parts of the valve and its extension rod to avoid damage to the valve actuator , Causing the valve to be unable to switch or difficult to switch.

2. Welding of the valve

double plate check valve body

(1) After the valve is in place, the valve should be placed in the fully open position when preheating and welding the valve, otherwise, during the welding process, the ball of the ball valve and the gate plate of the gate valve will be stained with welding slag and put into production At this time, these attached welding slag will scratch the valve seat seal and cause internal leakage of the valve. In severe cases, the valve will fail.
(2) The valves must be supported on their respective bases or separately.
(3) After the valve is welded, if the valve needs to be rotated, a manual grease gun should be used to fill in grease. (4) Confirm that the sewage outlet and pressure outlet are closed.
(5) General ball valve installation has no directionality, but attention should be paid to the position of the operating side. Some ball valves are directional when installed, so they must be installed in accordance with the arrow mark on the valve body and cannot be reversed. For example, the inlet and outlet sides of some of the ball valves of the crude oil and product oil yards of the Western Pipeline use two types of valve seat sealing, one end uses a double piston effect valve seat, and the other end uses a self-draining seal valve seat. If installed in reverse, After commissioning, the valve will automatically release the pressure and a pipeline accident will occur.

3. Requirements after valve welding
(1) The valve should be filled with grease before pressure test after welding to ensure that the sealing surface of the valve is filled with grease, and the impurities attached to the sealing surface of the valve seat during welding are discharged with grease.
(2) Check the condition of the valve to ensure that all external joints are locked and not loose; confirm that the sewage outlet and pressure outlet are in a tightly locked state to prepare for pressure test.
(3) Operate the valve according to the pressure test plan and keep the valve in the specified position.
A valve is a device used to control fluid flow, pressure and direction. The fluid to be controlled can be liquid, gas, gas-liquid mixture or solid-liquid mixture. In oil, natural gas, coal, metallurgy and ore mining, processing and pipeline transportation systems; in petrochemical, chemical products, medicine and video production systems; in hydropower, thermal power and nuclear power generation systems; in urban construction In water supply and drainage heating and gas supply systems; in metallurgical production systems; in fluid systems of ships, vehicles, aircraft, aerospace and various sports machinery; in national defense production and new technology fields; in agricultural irrigation and drainage systems,, A large number of new varieties of valves are used.

Commonly used valve body material code description

September 17, 2020

Valve body material code description:

lug type butterfly valve body

The material of the valve body should first consider the physical properties (temperature, pressure) and chemical properties (corrosiveness) of the working medium. At the same time, you should also understand the cleanliness of the medium (with or without solid particles). In addition, it is necessary to refer to the relevant regulations and requirements of the country and the user department. Different valve body materials can meet the requirements of the valve in a variety of different working conditions. Correct and reasonable selection of valve materials can obtain the most economical service life and best performance of the valve.

code	valve body
Z	grey cast iron
T	copper and copper alloy
C	carbon steel
K	Malleable cast iron
Q	ductile cast iron
I	Chrome-molybdenum steel: 1Cr5Mo ZG1Cr5Mo
P	18-8series SS: Cr18Ni9Ti, ZG1Cr18Ni9Ti
R	1Mo2T series SS: Cr18Ni12Mo2Ti, ZG1Cr18Ni12Mo2Ti
V	Chrome Molybdenum Vanadium Steel:12Cr1Mo1V, ZG12Cr1Mo1V
S	plastic
L	aluminium alloy
H	Cr13 series SS
A	Titanium and Titanium alloy

Note: Gray cast iron valves with Pg≤16kgf/cm2, carbon steel valves with Pg≥25kgf/cm2, omit this code. Different valve models are suitable for different pressure levels. Therefore, when selecting the valve body material, the valve body material suitable for the working conditions should be determined according to different uses and different pressure levels.

The difference and selection of electric valve and pneumatic valve

September 15, 2020

With the progress and continuous reform of the times, my country’s valve products have also been innovated with the change of the times. At present, in the valve market where environmental protection and safety are increasingly

ductile iron, DI, butterfly valve, manufacturer, center line, TH valve

demanded, the use of automatic control devices such as electric valves and pneumatic valves is gradually becoming impossible Optional. The use of self-control valves is more energy-saving, safer and more reliable. Compared with the traditional manual valve, the movement speed is faster than the ordinary valve, which not only reduces the manpower, but also greatly improves the work efficiency.
Compared with the pneumatic valve, the electric valve has a simple structure and reliable operation, and its power source (power source or air source) is easy to solve for the remote operation point. The disadvantage is that the price is higher and the explosion-proof requirements are also higher. When selecting, comprehensive consideration should be given to factors such as the

electric ball valve

availability, price and control requirements of the power source. The selection of the valve generally first confirm the valve material, valve diameter, medium type, pipeline pressure, connection mode, control mode, medium temperature etc.

Electric valve selection: When electric valve is selected (the control mode of electric actuator is generally divided into on-off type and regulating type), in addition to the basic valve body diameter, pressure, material and other requirements, the following parameters should be provided:
1. Power supply parameters (including voltage, number of phases and frequency);

pneumatic ball valve

2. Running time and form of electric actuator;
3. Whether explosion-proof and explosion-proof grade are required;
4. Atmospheric protection level;
5. Overload protection requirements, such as over travel protection, over torque protection, etc.;
6. Local operation requirements, such as whether to bring a local operation handwheel;
7. Operation instruction requirements.
Pneumatic valve selection: When selecting pneumatic valves (the operating principle of pneumatic actuators can be divided into single-acting and double-acting), in addition to determining specific parameters such as valve body diameter, pressure, and material, the following parameters should also be provided:
1. Air source parameters (including air source pressure range, whether to bring your own gas storage tank, etc.)
2. Running time and form of pneumatic actuator
3. Whether explosion-proof and explosion-proof grade are required;
4. Atmospheric protection level;
5. Overload protection requirements, such as over travel protection, over torque protection, etc.;
6. Local operation requirements, such as whether to bring a local operation handwheel;
7. Operation instruction requirements.
As the level of industrial automation requirements has increased significantly, the demand for electric (pneumatic) valves is also increasing, and the control requirements for electric (pneumatic) valves have become more and more detailed and complex. For the correct selection of electric (pneumatic) valves, it not only involves the correct use of the product, but also may affect the safety of the entire pipeline system. Users should understand and understand the relevant selection knowledge.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Description and classification of valve connection

September 15, 2020

Classification and description of valve connection methods: Nowadays, the application range of valves is wider and

double flange butterfly valve body

wider, and corresponding valves should be used in different environments. The connection between the entire valve and the pipeline or equipment is different. Regardless of installation, use and maintenance, attention should be paid to the improper connection of the valve, which may cause the valve to run, leak, drip, and leak. Therefore, valve users should be treated in accordance with the situation of the user.
There are many types of valve connection. Common valve connection methods are: flange connection, butt connection, butt welding connection, thread connection, ferrule connection, clamp connection, self-sealing connection and other connection forms. This article will focus on the most common flange connection, butt welding connection and threaded connection in the installation process easy to explain the problems, I hope to help everyone.

Threaded valve: A simple connection method, often used for small valves. This connection is usually made by processing the valve inlet and outlet ends into tapered pipes or straight pipe threads, which can be connected to tapered pipe threaded joints or pipelines. Since this connection may have large leakage channels, sealants, sealing tape or fillers can be used to plug these channels. If the material of the valve body can be welded, but the expansion coefficient is very different, or the working temperature has a large range of variation, the threaded connection must be honey sealed. Threaded valves are mainly valves whose nominal diameter is below 50mm. If the diameter size is too large, the installation and sealing of the connection part will be very difficult. In order to facilitate the installation and removal of threaded valves, pipe joints can be used at appropriate positions in the pipeline system. Valves with a nominal diameter below 50mm can use pipe sockets as pipe joints, and the thread of the pipe socket connects the two connected parts together. …
Flanged valve: Flanged valve, the most used connection form among valves. Its installation and disassembly are relatively convenient. But it is heavier than the threaded valve, and the corresponding price is higher. Therefore, it is suitable for pipe connections of various diameters and pressures. However, when the temperature exceeds 350 degrees, the bolts, gaskets and flanges become loose, and the load of the bolts is significantly reduced, which may cause leakage to the flange connection with a large force.
Welded valve This connection is suitable for various pressures and temperatures, and is more reliable than flanged connections when used under heavy load conditions. However, it is difficult to disassemble and reinstall the valve connected by welding, so its use is limited to the occasions that usually can operate reliably for a long time, or where the use conditions are heavy and the temperature is high. Such as the pipelines of thermal power stations, nuclear power projects, and ethylene projects. Welded valves with a nominal diameter of less than 50mm usually have welding sockets to accept the pipeline at the end of the load. Since socket welding forms a gap between the socket and the pipe, it is possible that the gap will be corroded by some media. At the same time, the vibration of the pipe will fatigue the connection part, so the use of socket welding is limited. In the occasions where the nominal diameter is large, the use conditions are heavy, and the temperature is high, the valve body is often welded with grooves. At the same time, there are original requirements for the welding seam, and a skilled welder must be selected to complete this work.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Raised face flange and concave and convex face flange

September 14, 2020

Flange is used for the connection between two devices. The abbreviation refers to the form of the sealing surface. There are holes on it. The two flanges are connected by bolts. It is generally used for The mutual connection between

flanges

the shaft and the shaft is also used for the connection between the pipe ends; it is a detachable connection of a set of combined sealing structures that are connected by flanges, gaskets and bolts. The thickness of flanges with different pressures is different, and their use forms are also different.

Commonly used butterfly valves include wafer butterfly valves and flange butterfly valves. Wafer type butterfly valve uses double-head bolts to connect the valve between two pipe flanges. Flange type butterfly valve has flanges on the valve, and the two ends of the valve are flanged to the pipe flanges with bolts.
For the most common raised face flanges and concave and convex face flanges, in the flange connection, the raised face flange needs to be matched with the concave face flange, commonly known as one male and one female, and the raised face flange should be matched with the raised face flange. Generally speaking, raised face flanges should also be a kind of flat flanges, code-named RF, and the RF face can only be linked with the RF face. The code name of the raised face flange is M, and the M face flange needs to be connected with the FM face. One is female FM (Female Male), and the other is male M (Male). The pressure on the M/FM side is better than that on the RF side. Raised face flanges and raised face flanges are used in pairs, and the code name is RF. The comparison chart of the two is as follows:

RF, MFM flanges

The angle between the sealing surface of the raised face flange and the flange bolt connection surface is 45°, and the sealing surface of the concave and convex flange and the flange bolt connection surface are 90° angle, that is, the two sides are perpendicular .

Raised face flanges are more commonly used in the market, and generally there is no problem below 2.5MPa. Concave-convex flanges are more expensive and have better sealing effect, so the applicable pressure level is higher. When designing, it is more troublesome. For example, when you mention the equipment condition diagram, you must indicate what type of method it is. Lan, and then when the statistics take over the material, it is another matching flange.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

The matching function and principle of pneumatic valve accessories

September 14, 2020

Pneumatic valve is an actuator that uses compressed air to drive and operate the valve. Its opening and closing speed is relatively fast. It is often used for fast two-position cut-off and can also be used to adjust flow. Because it mainly relies on air to perform operations, so it has high practicability in flammable and explosive situations, and can be used to control gas, liquid, oil, and various corrosive media. However, there are many changes in the accessories in the pneumatic valve. With different accessories, various different control methods can not be achieved. The user can configure the corresponding valve according to the different work needs of the valve.

1. Pneumatic triplex is the most common accessory in pneumatic valves, and its function can be simply summarized

pneumatic valve structure

as: filtration + decompression + oil mist. Among them, the pressure reducing valve is a necessary accessory. The pneumatic valve of any function must be configured. Its function is to give the pneumatic valve a standard power source pressure, the standard value is 0.4-0.7MPa. The pressure reducing valve is a valve that reduces the inlet pressure to a certain required outlet pressure through adjustment, and relies on the energy of the medium itself to automatically maintain a stable outlet pressure. a. The role of the two-piece (filter, pressure reducing valve): complete the filtering and pressure-reducing function of the compressed instrument air b. The role of the three-piece (filter, pressure reducing valve, oil mist device): complete the function of the compressed instrument air Filtering and decompression function, and lubricate the air.

2. The pneumatic solenoid valve can also be called a directional control valve. For two-position valves that only need to be opened and closed, the solenoid valve is a necessary configuration. The solenoid valve achieves the on/off control of the pneumatic valve through excitation/demagnetization. Solenoid valves are often used to switch valves, and control the on and off of the air source and air circuit through voltage signals to control the opening and closing of the valve. Definition: A valve that uses an electromagnet to control the spool movement generally realizes the opening and closing of the valve by controlling the movement process of the pneumatic actuator.

3. The valve limit switch, also called the travel switch, can also be called the echo device. It is a field instrument for

Limit switch-valve

detecting valve status in the automatic control system. It is used to output the open or closed position of the valve as a switch (contact) signal, which is accepted by the program controller or the computer searches for sampling, and executes the next program after confirmation. The product can also be used for interlocking protection of important valves in the system and remote alarm indication. If you want to grasp the valve position status of the two-position valve, the valve limit switch is an effective configuration, which is an electrical switch used to indicate and feedback the limit position of the mechanical equipment.

4. Valve positioner, it is a necessary configuration for pneumatic control valves. The valve positioner can be used to control the position of the valve at any opening degree. It uses the valve stem displacement signal as the input feedback measurement signal and the controller output signal as the setting Signal, compare, when there is a deviation between the two, change its output signal to the actuator, make the actuator act, and establish a one-to-one correspondence between the valve stem displacement times and the controller output signal.
Note: If it is a regulating valve controlled by a safe condition, a solenoid valve must also be configured. The solenoid valve is used to force the valve to be in a safe valve position under unexpected conditions.

For large-capacity cylinder valves, in order to speed up the valve action, the pilot valve must also be configured. The role of the pilot valve is to drive the pilot valve with a small gas signal to switch the atmospheric pipeline, so that the cylinder valve has a better performance. There are many types of pilot valves for fast charging/discharging gas circuits, which should be selected according to the specific needs of pneumatic valves.

If the valve position to be mastered is a regulating valve, a valve opening transmitter must be installed, which can feed back the opening signal of the valve at any position. Due to the requirements of the equipment and technology, the valve may open normally, slowly close, or slowly open, and normally close, then a pneumatic damper is required. The damper is to control the amount of air flow through and adjust to achieve the required valve action speed.

The difference and application of stainless steel 430, 304, 316

September 14, 2020

Stainless steel 430, 304,316 are the material of valve body, valve stem/shaft, or valve disc/plate.

lug type butterfly valve body

430 ferritic stainless steel containing more than 12% chromium can prevent oxidation caused by natural factors. It is called stainless steel. It belongs to 430 ferritic stainless steel. It has low thermal expansion rate, excellent formability and oxidation resistance. The code name in JIS is 430, so it is also called 430 stainless steel.

Application of 430 ferritic stainless steel: 430 stainless steel (16Cr) is often used to make household appliances, heat-resistant appliances, burners, home appliances, class 2 tableware, kitchen sinks, exterior decoration materials, bolts, nuts, CD rods, screens .

The difference between 430 stainless steel and 304, 316 austenitic stainless steel: 430 stainless steel and 304, 316 austenitic stainless steel are identified by spectral analysis and chemical element analysis. Both 304 and 316 are austenitic stainless steels. 316 is made of 304 stainless steel with molybdenum added. Therefore, 316 stainless steel has much better seawater and rust resistance than 304.
The difference between 304, 316 and 430 lies in the rust resistance. In addition to chromium, 304 and 316 also contain elements such as nickel and molybdenum, and are non-magnetic. Therefore, the rust resistance of 304/316 austenitic stainless steel is better than 430 stainless steel is much better and the price is much higher. To

Can the 430 stainless steel magnet hold it? 304 and 316 are not magnetic and cannot be attracted by magnets. Generally, it does not generate heat in a high-voltage electromagnetic environment, so it is used more. Martensitic and 430 ferritic stainless steel, precipitation hardening stainless steel are magnetic, and magnets can attract them.

Will 430 stainless steel rust? 430 stainless steel cannot resist the oxidation caused by chemicals in the air. Because there are more and more acidic chemicals in the air, 430 stainless steel will still be oxidized (rusted) due to unnatural factors after being used for a period of time.

Which is better, 430 stainless steel or 304? 304 austenitic stainless steel has excellent corrosion resistance and no magnetism. Relatively speaking, austenitic stainless steel 304 is better than 430 ferritic stainless steel.

How expensive is 430 stainless steel compared to 304? Generally speaking, austenitic stainless steel 304 is twice as expensive as 430 stainless steel.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Posts

What is the difference between lining and vulcanized valve seat?

The role and classification of valves

The difference of cryogenic valve and ordinary temperature valve

Valve installation instructions and process precautions

Commonly used valve body material code description

The difference and selection of electric valve and pneumatic valve

Description and classification of valve connection

Raised face flange and concave and convex face flange

The matching function and principle of pneumatic valve accessories

The difference and application of stainless steel 430, 304, 316

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