Globe valve Archives

Electric globe valve model coding method

July 2, 2021

Representation method of electric shut-off valve model in China. Globe valve is also called cut-off valve or stop valve.
As a cut-off valve, the electric shut-off valve is the most widely used and one of the most important valves. It is not only suitable for medium and low pressure pipelines, but also for high pressure places, and is relatively durable. It

Globe valve (9)

relies on electric thrust to control the flow of the medium. However, since there are many types of electric shut-off valves and their structural forms are changeable, users should be familiar with the expression method of their model preparation when choosing electric shut-off valves, so as to avoid problems such as selecting the wrong type, replacing goods and returning goods!
The description of the electric shut-off valve model is represented by the code of the shut-off valve type, drive mode, connection mode, structure form, sealing material, nominal pressure, valve body material, etc., mainly for the model description of the existing electric shut-off valve products, such as customized When the material and structure of the globe valve products change, please select according to the valve preparation method.
The method of preparing the model of the electric shut-off valve:
Additional code for stop valve: W: means bellows, D: means low temperature, B: means heat preservation;
1) Type code of globe valve: J: means globe valve;
2) Stop valve transmission mode: manual without code, 5: bevel gear, 6: pneumatic, 9: electric;
3) Connection mode of stop valve: 4: flange connection, 6: welding;
4) The structure of the globe valve: 1 straight-through type, 2 Z-type straight-through, 3 three-way, 4-angle type, 5 Y-type DC type, 6 balanced straight-through type, 7 balanced angle type, 8-pin type;
5) Seal material of globe valve: F: fluorine rubber, H: stainless steel, N: nylon plastic, Y: cemented carbide, M: Monel alloy, W: valve body directly processed;
6) The nominal pressure of the shut-off valve: 16: means that the pressure of 1.6mpa is 16 kilograms, PN1.6-32mpa, IN150LB-1500LB, 5-63K;
7) Globe valve body material: A: titanium alloy, C: carbon steel, I: chromium molybdenum steel, P: stainless steel 304, R: stainless steel 316;
Examples of electric shut-off valve model preparation:

electric globe valve

J941F46-16C Electric flange fluorine-lined globe valve
1. J: indicates the stop valve;
2. 9: indicates that the transmission mode is electric;
3. 4: The connection method is flange connection;
4. 1: The structure is a straight flow channel;
5. F: The sealing material is fluorine rubber;
6. 16: Indicates that the nominal pressure is 1.6MPa;
7. C: Indicates that the valve body material is carbon 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

Pneumatic globe valve model preparation method

July 1, 2021

Pneumatic globe valve /cut-off valve model preparation method
Pneumatic shut-off valve is used to open and close the pipeline medium by compressed air, and the action speed is relatively faster. Different materials and seals are selected, which can be applied to various pressure, temperature

and medium conditions, and the seal is reliable and the performance is excellent. However, since there are many types of pneumatic stop valves and their structural forms are changeable, users should be familiar with their model designation method when choosing pneumatic stop valves, so as to avoid problems such as selecting the wrong type, replacing goods and returning goods!
Pneumatic globe valve model preparation instructions are represented by the code of the globe valve type, drive mode, connection mode, structure form, sealing material, nominal pressure, valve body material, etc., mainly for the model description of the existing pneumatic globe valve products, such as customized When the material and structure of the globe valve products change, please select according to the valve preparation method.
Pneumatic shut-off valve model preparation method:
Additional code for stop valve: W means bellows, D means low temperature, B means heat preservation;
1) Type code of globe valve: J means globe valve;
2) Stop valve transmission mode: manual without code, 5 bevel gear, 6 pneumatic, 9 electric;
3) Connection mode of stop valve: 4 flange connection, 6 welding;
4) The structure of the globe valve: 1 straight-through type, 2 Z-type straight-through, 3 three-way, 4-angle type, 5 Y-type DC type, 6 balanced straight-through type, 7 balanced angle type, 8-pin type;
5) Seal material of globe valve: F fluorine rubber, H stainless steel, N nylon plastic, Y cemented carbide, M Monel alloy, W valve body directly processed;
6) The nominal pressure of the shut-off valve: 16 means that the pressure of 1.6mpa is 16 kilograms, PN1.6-32mpa, IN150LB-1500LB, 5-63K;
7) Globe valve body material: A titanium alloy, C carbon steel, I chromium molybdenum steel, P stainless steel 304, R stainless steel 316;
Examples for the compilation of pneumatic shut-off valve models:

pneumatic globe valve

WJ641H-16C Pneumatic Bellows Globe Valve
1. W: means bellows
2. J: represents the stop valve;
3. 6: indicates that the transmission mode is pneumatic;
4. 4: The connection method is flange connection;
5. 1: The structure is a straight flow channel;
6. H: Hard seal made of stainless steel for the sealing pair;
7. 16: Indicates that the nominal pressure is 1.6MPa;
8. C: Indicates that the valve body material is carbon 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

bellows globe valve vs ordinary globe valve

June 29, 2021

The difference and comparison between bellows globe valve and ordinary globe valve
The bellows globe valve is also called the bellows seal globe valve. Through automatic seam welding, a metal barrier is formed between the fluid medium and the atmosphere to ensure the design of zero leakage of the valve stem. Compared with traditional globe valves, it has the following advantages:

Globe valve (9)

1. The bellows globe valve has a long service life, reduces the number of maintenance and lowers operating costs. The sturdy and durable bellows seal design ensures zero leakage of the valve stem and provides maintenance-free conditions.
2. The valve opening and closing torque is small, reducing labor intensity, and can drive any form of driving device, which is convenient for remote control.
3. The appearance is beautiful, the valve channel has a smooth streamline, and the flow resistance coefficient of the valve is reduced. It is a high-quality energy-saving product.
4. The outer seal of the valve adopts bellows seal and graphite, stainless steel gasket seal, the seal is reliable, and the sealing packing does not need to be replaced for long-term use. In industrial use, the leakage caused by the stop valve: high temperature, highly toxic, flammable and explosive, radiant medium, etc., not only pollute the environment, but also often cause significant personal and property losses. However, this type of valve is much safer and more stable, and strictly adopts foreign advanced standards in design and manufacturing.

Advantages and application of bellows globe valve The bellows globe valve has no leakage, and it is safer to be used in high-risk media. Ordinary globe valve is sealed with packing, the valve stem and packing will slide, and it is easy to leak at low temperature (spool).
The bellows cut-off valve uses a closed bellows that can be stretched and compressed to replace the packing seal, which can effectively prevent external leakage caused by packing loss. It is generally used for the transmission of highly permeable media, such as valves on hydrogen systems, as long as the bellows is not damaged, there is generally no leakage; while the general shut-off valve is sealed with packing, which is prone to leakage.
The opening or closing stroke of the valve stem of this kind of valve is relatively short, and it has a very reliable cut-off function. Also, because the change of the valve seat port is proportional to the stroke of the valve disc, it is very suitable for flow adjustment. Therefore, this type of valve is very suitable for use as a shut-off or adjustment and throttling.

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 between internally and externally threaded valves

June 1, 2021

Threaded valve (also called internal threaded valve) generally refers to a valve with internal or external thread on the valve body. It is mainly divided into internal threaded valve and external threaded valve. Corresponding to the pipeline. Usually threaded valves can only be manufactured with small diameters and are used for normal pressure or low pressure projects. If they are not available for high pressure work, they need to be used with welded link valves or flanged valves.

internally threaded valve and externally threaded valve

Common threaded valves are: threaded gate valve, threaded ball valve, threaded globe valve, threaded check valve.
The difference between internal threaded valve and external threaded valve:
From the point of use: Due to price and working flow requirements, most of the valves on the market use internal threaded valves. From the channel: Taking into account the thread connection, the passage of the external thread of the same caliber is smaller than the internal thread, the flow rate is faster, and the flow rate is small.
From the appearance: Most of the internal threads are pipe threads, the external threads are mostly taper threads, and the bite-type external threads are pipe threads.
In terms of pressure resistance: The wall of the valve with external thread of the same material is usually thicker than that of the internal thread (the smaller the passage, the thicker the wall), and the pressure resistance is greater. This is the reason why valves with high pressure ratings are all external threads. To
Sealing form of threaded valve:
1. Direct sealing: internal and external threads directly play a sealing role. In order to ensure that the joints are not leaking, they are often filled with lead oil, thread hemp and PTFE raw material tape; among them, PTFE raw material tape is widely used every day; this material has good corrosion resistance and extremely sealing effect. Good, it is convenient to use and store. When disassembling, it can be completely removed, because it is a non-sticky film, which is much better than lead oil and hemp.
2. Indirect sealing: the tightening force of the thread is transmitted to the gasket between the two planes, so that the gasket plays a sealing role.
Thread standard of threaded valve:
1. International standards ISO228/1, DIN259, are internal and external parallel threads, code G or PF (BSP.F);
2. German standard ISO7/1, DIN2999, BS21, taper external thread, parallel internal thread;
3. British standard ISO7/1, BS21, internal and external tapered thread, code PT or BSP.Tr or Rc;
4. American standard ANSIB21, internal and external tapered thread, code name NPT.

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

Valve selection basis and selection guide

September 18, 2020

How to select the righty type of valve? the following article will give you an idea how to choose the right structure/type valve.

Nowadays, there are more and more valves on the market, the types of valves are particularly complex, and the

ball valve working diagram-3D GIF animated presentation

structures and materials are all different. The selection of valves is very important for the long-term operation of the device in working conditions. Improper selection of valves and users’ ignorance of valves are the source of accidents and safety threats. Nowadays, the demand for valve products in the social industry is becoming more and more extensive, and users should have a further understanding and cognition of knowledge about valves and other aspects.

There are generally two types of valve characteristics, use characteristics and structural characteristics.

Use characteristics of the valve: It determines the main use performance and use range of the valve. The

butterfly valve working diagram-3D GIF animated presentation

characteristics of the valve use include: valve category (closed circuit valve, regulating valve, safety valve, etc.); product type (gate valve, globe valve, butterfly valve, ball valve) Etc.); the materials of the main parts of the valve (valve body, bonnet, valve stem, valve disc, sealing surface); valve transmission mode, etc.

The structural characteristics of the valve: it determines the structural characteristics of the valve installation, repair, maintenance and other methods. The structural characteristics include: the structural length and overall height of the valve, the connection form with the pipeline (flange connection, threaded connection, clamp Connection, external thread connection, welding end connection, etc.); the form of the sealing surface (inlaid ring, threaded ring, surfacing, spray welding, valve body); valve stem structure (rotating rod, lifting

gate valve working diagram-3D GIF animated presentation

rod), etc.

Valve selection steps:
1. Clarify the purpose of the valve in the equipment or device, and determine the working conditions of the valve: applicable medium, working pressure, working temperature, etc.
2. Determine the nominal diameter and connection method of the pipe connected to the valve: flange, thread, welding, ferrule, quick installation, etc.
3. Determine the method of operating the valve: manual, electric, electromagnetic, pneumatic or hydraulic, electrical linkage or electrohydraulic linkage, etc.
4. Determine the material of the valve housing and internal parts according to the medium, working pressure and

globe cut-off valve working diagram-3D GIF animated presentation

working temperature conveyed by the pipeline: gray cast iron, malleable cast iron, ductile iron, carbon steel, alloy steel, stainless acid-resistant steel, copper alloy, etc.
5 Select the type of valve: closed circuit valve, regulating valve, safety valve, etc.
6. Determine the valve type: gate valve, globe valve, ball valve, butterfly valve, throttle valve, safety valve, pressure reducing valve, steam trap, etc.
7. Determine the parameters of the valve: For automatic valves, first determine the allowable flow resistance, discharge capacity, back pressure, etc., according to different needs, and then determine the nominal diameter of the pipeline and the diameter of the valve seat hole.
8. Determine the geometric parameters of the selected valve: structural length, flange connection form and size, valve height dimension after opening and closing, connecting bolt hole size and number, overall valve outline size,

tilting disc swing check valve working diagram-3D GIF animated presentation

etc.
9. Use existing information: valve product catalog, valve product sample, etc. to select appropriate valve products.

Basis for valve selection:
1. The purpose, operating conditions and operation control mode of the selected valve.
2. The nature of the working medium: working pressure, working temperature, corrosion performance, whether it contains solid particles, whether the medium is toxic, whether it is flammable or explosive medium, the viscosity of the medium, etc.
3. Requirements for valve fluid characteristics: flow resistance, discharge capacity, flow characteristics, sealing level, etc.
4. Requirements for installation dimensions and external dimensions: nominal diameter, connection to the pipeline and connection dimensions, external dimensions or weight restrictions, etc.
5. Additional requirements for the reliability and service life of valve products and the explosion-proof performance of electric devices. (Note when selecting parameters: If the valve is to be used for control purposes, the following additional parameters must be determined: operation method, maximum and minimum flow requirements, pressure drop for normal flow, pressure drop when closed, maximum and minimum inlets of the valve Pressure.)

According to the above-mentioned basis and steps for selecting valves, the internal structure of various types of valves must be understood in detail when selecting valves reasonably and correctly, so that the correct choice can be made on the preferred valve. The ultimate control of the pipeline is the valve. The valve opening and closing parts control the flow mode of the medium in the pipeline. The shape of the valve flow channel makes the valve have a certain flow characteristic. This must be considered when selecting the most suitable valve for the pipeline system.

Valve flow characteristic curve and classification

September 18, 2020

The flow characteristic of the valve is the relationship between the relative flow of the medium flowing through the regulating valve and its opening under the condition that the pressure difference between the two ends of the valve remains constant. Flow characteristic is an important technical index and parameter of regulating valve. It is very important to make the correct selection in the application process of the control valve.

Flow characteristics of regulating valve

Valve flow characteristics can be defined as: the relative flow of the controlled medium flowing through the valve, and the relationship between the relative opening (relative displacement) of the valve is called the flow characteristics of the regulating valve. Generally speaking, it is divided into four types: straight line, equal percentage (logarithm), parabola and quick opening! The specific description and advantages are as follows:

1. The linear characteristic refers to the linear relationship between the relative flow of the valve and the relative opening, that is, the time constant of the flow change caused by the change of unit opening. The relative stroke of the linear characteristic is linear with the relative flow. The flow change caused by the change of unit stroke is constant. When the flow is large, the relative value of the flow changes little, and when the flow is small, the relative value of the flow changes greatly.

2. the equal percentage characteristic (logarithm) means that the relative flow change caused by the change of the unit opening is proportional to the relative flow at that point, that is, the amplification factor of the regulating valve changes, and it increases with the increase of the relative flow. The relative stroke and relative flow of equal percentage characteristics are not in a linear relationship. The change in flow caused by the change of unit stroke at each point of the stroke is proportional to the flow at this point, and the percentage of flow change is equal. Therefore, its advantage is that when the flow rate is small, the flow rate changes small, and when the flow rate is large, the flow rate changes greatly, that is, it has the same adjustment accuracy at different opening degrees.

3. the parabolic characteristic means that the relative flow change caused by the change of the relative opening of the unit is proportional to the square root of the relative flow value at this point. The flow rate changes in proportion to the two sides of the stroke, and generally has an intermediate characteristic between linear and equal percentage characteristics.

4. the quick opening flow characteristic means that there is a larger flow when the opening is small. With the increase of the opening, the flow can reach the maximum quickly, and then the opening is increased, and the flow change is small, so it is called For quick opening characteristics.

The flow characteristic of the diaphragm valve is close to the quick opening characteristic, the flow characteristic of the butterfly valve is close to the equal percentage characteristic, the flow characteristic of the gate valve is the linear characteristic, the flow characteristic of the ball valve is linear in the middle opening and closing stage, and the equal percentage characteristic in the middle opening.

Globe valve (9)

Under normal circumstances, ball valves and butterfly valves are usually not used for adjustment. If they are used for adjustment, they are only used for adjustment when the opening is small. Generally, they can be classified as quick-opening, and they are really used for adjustment. Most of them are basically cut-off valves (globe valve). The valve head is processed into a parabolic cone, spherical shape, etc., and different curve characteristics are used. Generally speaking, as an adjustment, the basic percentage characteristic is used more.

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

Comparison table of valve diameter and medium flow rate

September 14, 2020

It is well known that the flow rate and flow rate of the valve mainly depend on the diameter of the valve, and also

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

related to the resistance of the valve structure to the medium. At the same time, it has a certain internal connection with various factors such as the valve pressure, temperature and medium concentration. The flow channel area of the valve has a direct relationship with the flow rate and flow rate, and the flow rate and flow rate are two mutually dependent quantities. When the flow rate is constant, the flow rate is large, the flow channel area can be smaller; the flow rate is small, the flow channel area can be larger. On the contrary, the flow channel area is large, its flow velocity is small; the flow channel area is small, its flow velocity is large.
1. The flow rate of the medium is large, and the valve diameter can be smaller, but the resistance loss is large and the valve is easily damaged. If the flow velocity is large, it will have electrostatic effect on flammable and explosive media, causing danger; the flow velocity is too small, the efficiency is low and it is not economical. For the medium with high viscosity and explosive, the flow rate should be smaller. The flow rate of oil and liquid with high viscosity is selected according to the viscosity, generally 0.1～2m/s.
2. In general, the flow rate is known, and the flow rate can be determined by experience. The nominal diameter of the valve can be calculated through the flow rate and flow rate.
3. The valve diameter is the same, its structure type is different, and the fluid resistance is also different. Under the same conditions, the larger the resistance coefficient of the valve, the more the flow rate and flow rate of the fluid through the valve will drop; the smaller the valve resistance coefficient, the less the flow rate and flow rate of the fluid through the valve will drop.
The common flow rates of various media are shown in the following table:

liquid type	use condition	speed m/s
satuated vapor	DN>200	30-40
	DN=200-100	25-35
	DN<100	15-30
superheated steam	DN>200	40-60
	DN=200-100	30-50
	DN<100	20-40
low pressure steam	P<1.0 (absolute pressure)	15-20
midium pressure steam	P=1.0-4.0 (absolute pressure)	20-40
high pressure steam	P=4.0-12.0 (absolute pressure)	40-60
compressed air	vaccum	5-10
	P≤0.3 (instrument pressure)	8-12
	P=0.3-0.6 (instrument pressure)	10-20
	P=0.6-1.0 (instrument pressure)	10-15
	P=1.0-2.- (instrument pressure)	8-12
	P=2.0-3.0 (instrument pressure)	3-6
	P=3.0-30.0 (instrument pressure)	0.5-3
Oxygen	P=0-0.05 (instrument pressure)	5-10
	P=0.05-0.6 (instrument pressure)	7-8
	P=0.6-1.0 (instrument pressure)	4-6
	P=1.0-2.0 (instrument pressure)	4-5
	P=2.0-3.0 (instrument pressure)	3-4
gas		2.5-15
semi-water gas	P=0.1-0.15 (instrument pressure)	10-15
natural gas		30
Nitrogen	P=5.0-10.0 (absolute pressure)	15-25
Ammonia	vaccum	15-25
	P<0.3 (instrument pressure)	8-15
	P<0.6 (instrument pressure)	10-20
	P≤2 (instrument pressure)	3-8
Acetylene water		30
Acetylene water		5-6
Acetylene gas	P<0.01 (instrument pressure)	3-4
	P<0.15 (instrument pressure)	4-8
	P<0.25 (instrument pressure)	5
chlorine	gas	10-25
chlorine	liquid	1.6
Hydrogen chloride	gas	20
Hydrogen chloride	liquid	1.5
liquid ammonia	vaccum	0.05-0.3
	P≤0.6 (instrument pressure)	0.3-0.8
	P≤2.0 (instrument pressure)	0.8-1.5
Sodium hydroxide	concentration 0-30%	2
	concentration 30-50%	1.5
	concentration 50-73%	1.2
Sulfuric acid	concentration 88-93%	1.2
Sulfuric acid	concentration 93-100%	1.2
hydrochloric acid		1.5
water and other similar viscosity liquid	P=0.1-0.3 (instrument pressure)	0.5-2
	P≤1.0 (instrument pressure)	0.5-3
	P≤8.0 (instrument pressure)	2-3
	P≤20-30 (instrument pressure)	2-3.5
	Heating network circulating water Cooling water	0.3-1
	pressure backwater	0.5-2
	pressureless backwater	0.5-1.2
tap water	main pipe P=0.3 (instrument pressure)	1.5-3.5
tap water	sub pipe P=0.3 (instrument pressure)	1-1.5
boiler feed water		>3
steam condensate		0.5-1.5
condensate	free flow	0.2-0.5
superheated water		2
seawater and brackish water	P<0.6 (instrument pressure)	1.5-2.5

Note: The unit of DN value is mm; the unit of P value is MPa.
for example:
The resistance coefficient of the gate valve is small, only in the range of 0.1 to 1.5; the resistance coefficient of the large diameter gate valve is 0.2 to 0.5; the resistance coefficient of the narrow gate valve is larger.
The resistance coefficient of the stop valve is much larger than that of the gate valve, generally between 4 and 7.
The resistance coefficient of the Y-type globe valve (DC type) is small, between 1.5 and 2; the resistance coefficient of the forged steel globe valve is large, even as high as 8.
The resistance coefficient of the check valve depends on the structure: the swing check valve is usually about 0.8-2, among which the multi-leaf swing check valve has a large resistance coefficient; the lift check valve has a large resistance coefficient, up to 12 .
The resistance coefficient of the plug valve is small, usually about 0.4 to 1.2.
The resistance coefficient of the diaphragm valve is generally around 2.3.
The drag coefficient of butterfly valve is small, generally within 0.5. The resistance coefficient of the ball valve is small, generally around 0.1.
Note: The resistance coefficient of the above valve is the value when the valve is fully opened. The selection of valve diameter should take into account the machining accuracy and dimensional deviation of the valve, as well as other factors. The valve diameter should have a certain margin, generally 15%. In actual work, the valve diameter depends on the diameter of the process 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

Principles of valve selection in the petroleum and chemical industry

September 14, 2020

Faced with so many valve classifications and such complex various working conditions, to choose the most suitable

lug type butterfly valve, ductile iron, center lined,

valve product for piping system installation, you should first understand the characteristics of the valve; secondly, you should master the steps and basis for selecting the valve; and then you should follow the choice of oil , The principle of valves used in the chemical industry. The principle of selecting valves in the petroleum and chemical industries: the flow path is a straight-through valve, and its flow resistance is small, and it is usually selected as a shut-off and open medium valve; a valve that is easy to adjust the flow is used as a control flow; a plug valve and a ball valve are more suitable Used for reversing and shunting; the sliding of the closing part along the sealing surface of the valve with wiping effect is most suitable for the medium with suspended particles.

1. Valves for shut-off and open media: The flow channel is a straight-through valve with low flow resistance. It is usually selected as a valve for shut-off and open media. The downward closing valve (stop valve, plunger valve) is less used because of its tortuous flow path and higher flow resistance than other valves. Where higher flow resistance is allowed, a closed valve can be used.

Globe valve (9)

2. Valves used for flow control: Generally, valves that are easy to adjust flow are selected as flow control valves. Downward closing valves (such as globe valves) are suitable for this purpose because the size of its seat is proportional to the stroke of the closing member. Rotary valves (plug valves, butterfly valves, ball valves) and flex-body valves (pinch valves, diaphragm valves) can also be used for throttling control, but they are usually only applicable in a limited range of valve diameters. The gate valve uses a disc-shaped gate to cross-cut the circular valve seat port. It can only control the flow better when it is close to the closed position, so it is usually not used for flow control. 3. Valves for reversing and shunting According to the needs of reversing and shunting, this kind of valve can have three or more channels. Plug valves and ball valves are more suitable for this purpose. Therefore, most of the valves used for reversing and splitting use one of the plug valves and ball valves. However, in some cases, other types of valves can also be used for reversing and shunting as long as two or more valves are properly connected to each other.

4. Valves for medium with suspended particles When there are suspended particles in the medium, it is most suitable for valves with a wiping effect on the sliding of the closing part along the sealing surface. If the back and forth movement of the closing member to the valve seat is vertical, it may hold particles. Therefore, unless the sealing surface material allows particles to be embedded, this valve is only suitable for basic clean media. Ball valves, plug valves, and butterfly valves have a wiping effect on the sealing surface during opening and closing, so they are suitable for use in media with suspended particles.

At present, no matter in the pipeline system of petroleum, chemical industry, or other industries, valve applications, operating frequencies and services are ever-changing. To control or eliminate even low-level leakage, the most important and critical equipment is still valves. The ultimate control of the pipeline is the valve. The service and reliable performance of the valve in various industries are unique.

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

Classification of valves

August 18, 2020

Valve classification by function and purpose:

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

(1) Cut-off type: such as gate valve, globe valve, plug valve, ball valve, butterfly valve, needle valve, diaphragm valve, etc. The cut-off valve is also called a closed-circuit valve or a cut-off valve, whose function is to connect or cut off the medium in the pipeline.

Check valve, also known as one-way valve or check valve, check valve is an automatic valve, its function is to prevent the back flow of the medium in the pipeline, prevent the pump and drive motor from reversing, and the leakage of the container medium . The bottom valve of the pump to close the water is also a check valve.

Explosion-proof valves, emergency valves, etc. The role 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.

Regulating valve, throttle valve and pressure reducing valve, its role is to adjust the pressure, flow and other parameters of the medium.

(2) Vacuum: such as vacuum ball valve, vacuum baffle valve, vacuum charging valve, pneumatic vacuum valve, etc. Its role is in the vacuum system to change

The vacuum system components that adjust the air flow direction, cut off or connect the pipeline are called vacuum valves.

(3) Special purpose categories: such as pigging valve, vent valve, drain valve, exhaust valve, filter, etc. The exhaust valve is an indispensable auxiliary component in the pipeline system, which is widely used in boilers, air conditioners, oil and gas, and water supply and drainage pipelines. 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.

According to the main parameters:

According to the nominal pressure:

lug type butterfly valve, ductile iron, center lined,

(1) Vacuum valve: refers to a valve whose working pressure is lower than the standard atmospheric pressure.
(2) Low pressure valve: refers to the valve with a nominal pressure PN ≤ 1.6Mpa.
(3) Medium pressure valve: refers to valves with nominal pressure PN of 2.5Mpa, 4.0Mpa, 6.4Mpa.
(4) High-pressure valve: refers to the valve whose nominal pressure PN is 10.0Mpa~80.0Mpa.
(5) Ultra-high pressure valve: refers to a valve with a nominal pressure PN≥100.0Mpa.
(6) Filter: Refers to the nominal pressure PN is 1.0Mpa, 1.6Mpa

According to working temperature

(1) Ultra-low temperature valve: used for valves with medium working temperature t<-101℃.
(2) Normal temperature valve: used for valves with medium working temperature -29℃<t<120℃.
(3) Medium temperature valve: used for valves with a working temperature of 120℃<t<425℃.
(4) High temperature valve: used for valves with medium working temperature t>425℃.

By driving method:

According to the driving mode, it is divided into automatic valves, power-driven valves and manual valves

Valves driven by compressed air. Hydraulic valve: A valve driven by the pressure of liquids such as oil.

In addition, there are combinations of the above several driving methods, such as pneumatic-electric valves.

According to the nominal diameter:

(1) Small diameter valve: Valve with nominal diameter DN≤40mm.
(2) Middle diameter valve: a valve whose nominal diameter DN is 50~300mm.
(3) Large diameter valve: a valve with a nominal valve DN of 350~1200mm.
(4) Extra large diameter valves: valves with nominal diameter DN ≥ 1400mm

6. According to structural characteristics:

Valve structure characteristics:

The structural features of the valve can be divided into:

(1) Sectional gate shape: The closing part moves along the center of the valve seat; such as a globe valve
(2) Cock and ball: The closing part is a plunger or a ball, which rotates around its own centerline; such as a plug valve, a ball valve
(3) Gate shape: The closing part moves along the center of the vertical valve seat; such as gate valve, gate, etc.
(4) Swing shape: The closing part rotates around the axis outside the valve seat; such as swing check valve, etc.
(5) Butterfly shape: the disc of the closing part, which rotates around the axis in the valve seat; such as butterfly valve, butterfly check valve, etc.
(6) Slide valve shape: The closing piece slides in a direction perpendicular to the channel. Slippery

Press connection method:

(1) Threaded connection valve: The valve body has an internal thread or an external thread, which is connected with the pipe thread…
(2) Flange connection valve: The valve body has a flange and is connected to the pipeline flange.
(3) Welding connection valve: The valve body has a welding groove and is welded to the pipeline.
(4) Clamp connection valve: The valve body has a clamp, which is connected with the pipe clamp.
(5) Ferrule connection valve: the ferrule is connected to the pipeline.
(6) Wafer connection valve: a connection form in which the valve and two pipes are directly clamped together with bolts.

According to the body material

(1) Metal material valve: its valve body and other parts are made of metal material. Such as cast iron valves, cast steel valves, alloy steel valves, copper alloy valves, aluminum alloy valves, lead alloy valves, titanium alloy valves, Monel alloy valves, etc.
(2) Non-metallic material valve: its valve body and other parts are made of non-metallic material. Such as plastic valves, enamel valves, ceramic valves, FRP valves, etc.

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

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