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Ball valve model preparation method/code name establishment

Ball valve model preparation method/code name establishment in China.
With the rapid development of my country’s industrial modernization, the use of valves is also increasing.  Ball valves have the advantages of fast opening and closing speed, and not only can switch and cut off, but also control flow, etc., and become the most widely used valve type. one! However, due to the wide variety of ball valves, including the use of pressure, temperature and control methods, the corresponding ball valve models are also different. In order to avoid errors in the selection of the user, and to ensure that the ball valve can be used normally, more instruments Self-Control Valve Company hereby provides instructions for the preparation of ball valve models for everyone to understand and recognize!

Pneumatic electric high platform ball valve

Pneumatic electric high platform ball valve

Ball valve model editing instructions are mainly from the increase of additional conditions of the  ball valve, the selection of the drive mode, the difference of the connection form, the change of the structure form, the type of sealing material, the level of valve pressure and the material of the valve body, etc. to facilitate the explanation, hope It is helpful to the majority of users.
Ball valve model representation method:
Ball valve additional code: V means the valve core has a V-shaped structure, D means low temperature, B means heat preservation, P means eccentric structure, U, S and DY mostly mean top-mounted type;
Ball valve name code: Q means ball valve; Ball valve drive code: 2 means electro-hydraulic, 3 means turbine, 6 means pneumatic, 7 means hydraulic, 9 means electric, manual without code;
Code of connection method: 1 means internal thread, 4 means flange type, 6 means welding, 7 means wafer type;
Structural type code: Floating type: 1 means straight-through runner, 2 means Y-type tee, 4 means L-type tee, 5 means T-type tee; Fixed type: 0 means hemispherical through, 6 means four-way runner, 7 Means straight-through flow to, 8 means L-type tee, 9 means Y-type tee;

fixed ball valve

fixed ball valve

Sealing material code: B babbitt alloy, F fluorine rubber, F46 lining fluorine, H stainless steel, J rubber lining, M Monel alloy, N nylon plastic, Monel P, Y cemented carbide, W valve body directly processed;
Pressure rating code: 16 means the pressure is 16 kg (1.6Mpa) and the maximum can reach 64Mpa; 150LB means the American standard pound pressure, and the maximum pressure rating can reach 2500LB (150LB=1.6MPA/300LB=2.5-4.0mpa/400LB=6.4 mpa/600LB=10mpa); 5K means Japanese pressure, maximum pressure is 63K; Valve body material code: A titanium and titanium alloy, C carbon steel, I chromium molybdenum steel, P18-8 series stainless steel, RMo2Ti series stainless steel, S plastic.
ball valve model editing instructions:
Q645F-16P Stainless steel pneumatic flange three-way ball valve
1. Q: represents the ball valve;
2. 6: It means that the transmission mode is pneumatic;
3. 4: The connection method is flange connection;
4. 5: The structure is a floating T-type tee;
5. F: The sealing material is fluorine rubber;
6. 16: Indicates that the nominal pressure is 1.6MPa;
7. P: indicates that the valve body is made of stainless steel.

Editing instructions for electric ball valve model:
VQ947F-16P Stainless steel electric flange V-shaped ball valve
1. V: indicates that the spool has a V-shaped structure
2. Q: represents the ball valve;
3. 9: indicates that the transmission mode is electric;
4. 4: The connection method is flange connection;
5. 7: The structure is a fixed straight flow channel;
6. F: The sealing material is fluorine rubber;
7. 16: Indicates that the nominal pressure is 1.6MPa;
8. P: indicates that the valve body is made of stainless steel.

More details for valve model establishment, you can visit another article: https://www.tanghaivalve.com/valve-model-establishment-and-meaning/

TH Valve is a professional manufacturer of butterfly valvegate valvecheck valveglobe valveknife 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

7 types of flange sealing surface: FF, RF, M, FM, T, G, RTJ

Flanged butterfly valve has a flange on the valve, and bolts are used to connect the flanges at both ends of the valve to the pipe flange. Do you know all the 7 types of flange sealing surfaces? FF, RF, MF, M, T, G, RTJ
The flange sealing surface basically has:

Full plane: FF
Raised face: RF
Concave/female: FM
Convex/Male: M
Tenon: T
Groove surface: G
Ring connection surface RTJ (RJ)  types, according to the different working conditions, medium, pressure, specifications, temperature, etc., so the selected types are not the same. Let’s get to know the types of these flange sealing surfaces together!
FF-full plane:
Flat Face Full Face type sealing surface is completely flat, suitable for occasions where the pressure is not high and the medium is non-toxic.

flange FF

flange FF 

RF-raised face:
The Raised Face type of sealing surface is the most widely used among several types, and the most commonly used one. The international standards, European system and domestic standards are all fixed heights, but in the American standard flange, it should be noted that the height of high pressure will increase the sealing surface. There are also many types of gaskets used. Gaskets suitable for raised face sealing surface flanges include various non-metallic flat gaskets, coated gaskets; metal-wrapped gaskets; spiral wound gaskets (including outer ring or inner and outer ring).

flange RF

flange RF

Convex/Male: M
Concave /female: FM
The two types of sealing surfaces, Male Face and Female Face, are a pair, one female and one male. They must be used together. They are easy to align and prevent the gasket from being extruded. Suitable for occasions with higher pressure.
The suitable sealing gaskets for the concave-convex sealing surface include: various non-metallic flat gaskets and coated gaskets; metal-clad gaskets; basic type or winding stopper with inner ring, etc.
T-tenon
G-groove surface
Tongue Face and Groove Face are similar to the concave-convex surface. They are also a male and female matched sealing surface type, and they are also used in pairs. The gasket is located in the annular groove and is restricted by the metal walls on both sides. It can prevent the gasket from being compressed and deformed and squeezed into the pipeline. Since the gasket is not in direct contact with the fluid medium in the pipe, it is less eroded or corroded by the fluid medium, so it can be used for high pressure, flammable, explosive, and toxic mediums that require strict sealing. This kind of sealing surface gasket has good installation and neutrality, but it is difficult to process the sealing surface. It is easy to damage the sealing surface when replacing the gasket, and the flange must be separated in the axial direction during installation and disassembly. Therefore, consideration should be given to the pipeline design. It is possible to separate the flange in the axial direction.
Suitable gaskets for the sealing surface of the tongue and groove surface include: various metal and non-metal flat gaskets, metal-clad gaskets and basic spiral wound gaskets.

flange TG-

flange TG-

RTJ(RJ)-Ring connection surface
The flange of the Ring Joint Face seal is also a narrow-face flange, and an annular trapezoidal groove is opened on the flange surface as the flange sealing surface, which is the same as the tongue-and-groove flange. The flange must be separated in the axial direction during installation and disassembly. Therefore, the possibility of separating the flange in the axial direction should be considered in the pipeline design.
The sealing surface is specially designed to cooperate with solid metal gaskets processed into octagonal or elliptical shapes from metal materials to achieve a sealed connection. Since the metal ring gasket can be based on the inherent characteristics of various metals, the sealing performance of this sealing surface is good, and the installation requirements are not too strict. It is suitable for high temperature and high pressure working conditions, but the processing accuracy of the sealing surface is relatively high. (According to the Pipe Fittings, Pumps and Valves Alliance)

flange-RTJ-RJ-

flange-RTJ-RJ-

flange-RTJ-RJ-02

flange-RTJ-RJ-02

The chemical composition, characteristics and applications of rubbers

Here we will introduce Rubber variety (abbreviated symbol) with their Chemical composition, Performance characteristics and Main application.

1. Natural rubber (NR) is mainly rubber hydrocarbon (polyisoprene), containing a small amount of protein, moisture, resin acid, sugar and inorganic salt. Large elasticity, high tensile strength, excellent tear resistance and electrical insulation, good wear resistance and drought resistance, good processability, easy to bond with other materials, and superior to most synthetic rubbers in comprehensive performance. Disadvantages are poor resistance to oxygen and ozone, easy to aging and deterioration; poor resistance to oil and solvents, low resistance to acid and alkali, and low heat resistance. Operating temperature range: about -60℃~+80℃. Production of tires, rubber shoes, hoses, tapes, insulation layers and sheaths of wires and cables, and other general products. It is especially suitable for manufacturing torsional vibration eliminators, engine shock absorbers, machine supports, rubber-metal

lug type butterfly valve-ductile iron

lug type butterfly valve-ductile iron

suspension components, diaphragms, and molded products.

2. Styrene butadiene rubber (SBR) is a copolymer of butadiene and styrene.
The performance is close to natural rubber, and it is currently the largest output of general-purpose synthetic rubber. It is characterized by abrasion resistance, aging resistance and heat resistance exceeding natural rubber, and its texture is more uniform than natural rubber. The disadvantages are: low elasticity, poor flex resistance and tear resistance; poor processing performance, especially poor self-adhesiveness and low green rubber strength. Operating temperature range: about -50℃~+100℃.
Mainly used to replace natural rubber to make tires, rubber sheets, hoses, rubber shoes and other general products.

3. Butadiene rubber (BR)
It is a cis-structure rubber formed by polymerization of butadiene. The advantages are: excellent elasticity and wear resistance, good aging resistance, excellent low temperature resistance, low heat generation under dynamic load, and easy metal bonding. The disadvantages are low strength, poor tear resistance, poor processing performance and self-adhesiveness. Operating temperature range: about -60℃~+100℃.
Generally used together with natural rubber or styrene-butadiene rubber, mainly to make tire treads, conveyor belts and special cold-resistant products.

4. Isoprene rubber (IR) is a kind of cis structure rubber made by polymerization of isoprene monomer. The che

Wafer butterfly valve-PN20-WCB-ANSI-150 (4)

Wafer butterfly valve-PN20-WCB-ANSI-150 (4)

mical composition and three-dimensional structure are similar to natural rubber, and the performance is very close to natural rubber, so it is called synthetic natural rubber. It has most of the advantages of natural rubber. Due to its aging resistance, natural rubber has slightly lower elasticity and strength than natural rubber, poor processing performance and higher cost. Operating temperature range: about -50℃~+100℃ It can replace natural rubber to make tires, rubber shoes, hoses, tapes and other general products.

5. Chloroprene rubber (CR) is a polymer formed by emulsion polymerization of chloroprene as monomer.
This kind of rubber contains chlorine atoms in its molecule, so compared with other general rubbers: it has excellent antioxidant, ozone resistance, non-flammable, self-extinguishing after fire, oil resistance, solvent resistance, acid and alkali resistance, aging and gas resistance. Advantages such as good tightness;
Its physical and mechanical properties are also better than natural rubber, so it can be used as general-purpose rubber as well as special rubber. The main disadvantages are poor cold resistance, large specific gravity, high relative cost, poor electrical insulation, and easy sticking, scorching, and mold sticking during processing. In addition, the raw rubber has poor stability and is not easy to store. Operating temperature range: about -45℃~+100℃. It is mainly used to manufacture cable sheaths and various protective covers and protective covers that require high ozone resistance and high aging resistance; oil and chemical resistance hoses, tapes and chemical linings; flame-resistant rubber products for underground mining, and various moldings Products, sealing rings, gaskets, adhesives, etc.

6. Butyl rubber (IIR) is a copolymer of isobutylene and a small amount of isoprene or butadiene. The biggest feature is good air tightness, good ozone resistance, good aging resistance, high heat resistance, long-term working temperature can be below 130 ℃; resistance to strong inorganic acids (such as sulfuric acid, nitric acid, etc.) and general organic solvents, vibration absorption and damping characteristics Good and very good electrical insulation. The disadvantages are poor elasticity, poor processing performance, slow vulcanization speed, and poor adhesion and oil resistance. Operating temperature range: about -40℃~+120℃. Mainly used as inner tube, water tyre, balloon, wire and cable insulation layer, chemical equipment lining and shockproof products, heat-resistant conveyor belt, heat-resistant aging tape products.

7. Butadiene rubber (NBR) Copolymer of butadiene and acrylonitrile. It is characterized by its excellent resistance to gasoline and aliphatic hydrocarbon oils, second only to polysulfide rubber, acrylic ester and fluorine rubber, but better than other general rubbers. Good heat resistance, good air tightness, abrasion resistance and water resistance, and strong adhesion. The disadvantages are poor cold resistance and ozone resistance, low strength and elasticity, poor acid resistance, poor electrical insulation, and poor resistance to polar solvents. Operating temperature range: about -30℃~+100℃. Mainly used to manufacture various oil-resistant products, such as hoses, sealing products, etc.

8. Hydrogenated butadiene rubber (HNBR) is a copolymer of butadiene and acrylonitrile. It is obtained by fully or partially hydrogenating the double bonds in the butadiene of NBR.
It is characterized by high mechanical strength and abrasion resistance, and its heat resistance is better than NBR when crosslinked with peroxide
Good, other properties are the same as nitrile rubber. The disadvantage is that the price is higher. Operating temperature range: about -30℃~+150℃. Mainly used for oil and high temperature resistant sealing products.

9. Ethylene propylene rubber (EPM\\EPDM)
The copolymer of ethylene and propylene is generally divided into two yuan ethylene propylene rubber and three yuan ethylene propylene rubber.
It is characterized by excellent ozone resistance, ultraviolet resistance, weather resistance and aging resistance, ranking first in general rubber. Electrical insulation, chemical resistance, impact elasticity, acid and alkali resistance, low specific gravity, high filling compounding is possible. Heat resistance up to 150°C, resistance to polar solvents-ketones, esters, etc., but not to aliphatic and aromatic hydrocarbons. Other physical and mechanical properties are slightly inferior to natural rubber and superior to styrene butadiene rubber. The disadvantage is that the self-adhesion and mutual adhesion are very poor, and it is not easy to bond. Operating temperature range: about -50℃~+150℃. Mainly used as chemical equipment lining, wire and cable sheathing, steam hose, heat-resistant conveyor belt, rubber products for automobiles and other industrial products.

10. Silicone rubber (Q)
It is a special rubber with silicon and oxygen atoms in the main chain, of which silicon element plays a major role. Its main feature is high temperature resistance (maximum 300℃) and low temperature resistance (minimum -100℃). It is currently the best high temperature resistant rubber. It has excellent electrical insulation and high stability to thermal oxidation and ozone. , Chemically inert. The disadvantage is that the mechanical strength is low, oil resistance, solvent resistance, acid and alkali resistance are poor, it is difficult to vulcanize, and the price is more expensive. Operating temperature: -60℃~+200℃.

Tanghai Valve is the best manufacturer of  butterfly valve, check valve, knife gate valve in China. We produce the best quality products with competitive low prices.

Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest butterfly valve manufacturers in China, main products are butterfly valves, check valves, gate valve and globe valves. Key words:  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…)

URL: http://www.tanghaivalve.com

Name: Harry Li

Email: harry@tanghaivalve.com

Classification and introduction of pipe thread-(3)

Sealing pipe thread (R)

The basic dimensions and tolerances of inch sealing pipe threads

Cooperate way

There are two matching methods for inch seal pipe threads: cylindrical internal thread and conical external thread form a “column/cone” fit; conical internal thread and conical external threa

NPT thread picture

NPT thread picture

d form a “cone/cone” fit.

European countries mainly use “column/cone” matching threads; countries outside Europe mainly use “cone/cone” matching threads. The inspection gauges for the two types of threads are somewhat different; the current ISO inch seal pipe thread gauge standard (ISO 7- 2:2000) is designed according to the “column/cone” coordination system.

mark

The complete mark of inch seal pipe thread is composed of thread feature code, thread size code and rotation direction code.

The characteristic code of inch sealed cylindrical internal thread is: RP;

left &right hand thread

left &right hand thread

The characteristic code of the inch sealing cone internal thread is: RC;

The characteristic code of the inch sealing cone external thread is: R1 (used with the inch sealing cylindrical internal thread);

R2 (used in conjunction with inch sealing cone internal thread);

The rotation code of the left-hand thread is LH; the rotation code of the right-hand thread is omitted and not marked.

For sealing pipe threads, use RP/R1 and RC/R2 to indicate “column/cone” and “cone/cone” thread pairs respectively.

Unsealed pipe thread

The basic size and limit deviation of the imperial unsealed pipe

mark:

The complete mark of inch unsealed pipe thread is composed of thread feature code, thread size code, pitch diameter tolerance grade code and rotation direction code.

The characteristic code of inch unsealed cylindrical thread is: G

For inch non-sealed cylindrical internal threads, the codes for the tolerance grades of the median diameter are omitted and not marked; while the codes for the pitch diameter and metric grades of the inch non-sealed cylindrical external threads are A and B respectively.

When indicating the thread pair of the inch unsealed pipe thread, only the marking code of the external thread is marked.

Example:

Right-handed, non-sealed cylindrical female thread with size code 2: G2

Class A with size code 3, right-handed, unsealed cylindrical external thread: G3A

Grade B with size code 4, left-handed, unsealed cylindrical external thread: G4 B-LH

Thread pair consisting of a right-handed, non-sealed cylindrical internal thread and a grade A cylindrical external thread with a dimension code of 2: G2A

The inner thread is processed by pipe thread taps, and the outer thread has die.

Note: 2, 3, 4 above are code names, not inch sizes, don’t confuse

other

Conversion of 55° tapered pipe thread

55° tapered pipe thread means that the thread angle is 55° and the thread has a taper of 1:16. This series of thread is widely used in the world, and its code is different from country to country.

China UK France Japan iso

Code ZG R (outside) G PT R

R (external thread) Rc (internal) R R Rc

Conversion of 60° Conical Pipe Thread

The 60° tapered pipe thread refers to a pipe thread with a tooth profile angle of 60° and a thread taper of 1:16. This series of threads is used in the machine tool industry in my country, the United States and the former Soviet Union. Its code name was previously designated as K in our country, and later designated as Z, now it is changed to NPT.

Classification and introduction of pipe thread-(2)

“Cylinder/cone” and “cone/cone”. Two inch seal pipe threads use different thread ring gauges (cylindrical thread ring gauge and tapered thread ring gauge) and thread plug gauge (the position of the datum plane is different, the two datum planes are different Half-tooth apart). Pipe threads that pass the inspection in European countries may be unqualified if they are inspected by countries outside of Europe. In international trade, you must pay attention to this difference, otherwise there may be waste. Before 1994, the ISO standard for sealed pipe threads and their gauges The standard is designed according to the “cone/cone” coordination system. China’s imperial sealed pipe thread products can directly enter the international market. However, the pipe thread products of European countries are in a disadvantageous position. After 2000, ISO’s imperial seal The pipe thread standard and its gauge standard are designed according to the “column/cone” matching question system. Our country’s original inch seal pipe thread products will encounter difficulties when entering the international market. For this reason, China revised the inch seal pipe in 2000 Thread national standard. Change the original one thread standard into two thread standards to remind the designer to pay attention to the difference and correct selection of the two mating threads. Japan still insisted on adopting 1994 when it revised the inch seal pipe thread standard in 1999 The ISO standard a year ago. Therefore, the international inch seal pipe thread market after 2000 is more complicated, and domestic

NPT thread picture

NPT thread picture

manufacturers must be careful.

Inch sealing pipe thread is a general purpose sealing pipe thread. Sealing filler should be added to the thread pair during use. Its characteristics are economical and the processing accuracy requirements are moderate. Without sealing fillers, it can ensure that the sealed connection thread is dry sealed Pipe thread. There is no dry seal pipe thread in the inch pipe thread system.

Sealed pipe threads have two functions: mechanical connection and sealing; non-sealed pipe threads have only one function of mechanical connection. Therefore, the accuracy of sealed pipe threads is stricter than that of unsealed pipe threads. Some people see unsealed pipe threads The tolerance of the pitch diameter is half of the tolerance of the sealed pipe thread. It is considered that the accuracy of the unsealed pipe thread is higher than that of the sealed pipe thread. This view is incorrect. The sealed pipe thread has requirements for the accuracy of the tooth shape. Its large diameter, The tolerances of the pitch diameter and the minor diameter are the same; the flank angle and pitch error have a greater impact on the sealing performance. The non-sealed pipe thread basically has no requirements for the accuracy of the tooth form. The top diameter tolerance is greater than the pitch diameter tolerance; the bottom diameter There is no tolerance requirement. In addition, some people think that it is possible to use non-sealed cylindrical internal threads and sealed cylindrical external threads to form a fit. This view is also wrong. This is equivalent to relaxing the accuracy requirements of sealed internal threads, and the sealing of pipe threads There may be a problem.

Due to differences in the use of sealed pipe threads, processing accuracy, assembly and testing techniques, the pipe thread standard cannot guarantee that all threaded parts that meet the standard can be sealed. In the imperial sealed pipe thread standard, a unified thread item cannot be proposed. The accuracy requirements of the parameters. These individual thread parameters have a direct impact on the sealing performance. The fundamental way to solve the problem is to formulate their own internal control measures for their specific products. Each industry or company formulates its own internal control measures. The internal control indicators of these parameters are generally confidential. Companies in other industries are not universal, and manufacturers must have a clear understanding of this. Sealing pipe thread standards are not omnipotent, and sealing problems may require manufacturers to pay attention to them. Before 1987, China did not have American and British pipe thread standards. But In production, these two internationally commonly used pipe thread standards cannot be avoided. For this reason, the old mechanical drawing standards once stipulated the marking codes for American and British pipe threads. These thread codes are derived from the Chinese Pinyin alphabet, and have not considered the foreign Whether the standard codes of standard pipe threads are consistent. Since this standard only specifies the thread codes and not the thread parameters, the same thread code may have different thread parameters in different companies or industries. There is no basis for judging who is right and who is wrong when there is a scrap .From 1987 to 1991, China promulgated the British pipe thread standard. From then on, the pipe thread code and marking should comply with the pipe thread standard. The pipe thread code specified in the old mechanical drawing standard should be abolished immediately.

Classification and introduction of pipe thread-(1)

Pipe thread is a thread used for connection on the pipe wall to the valves. There are 55-degree unsealed pipe threads and 55-degree sealed pipe threads. Mainly used to connect pipes to make the internal and external threads fit tightly. There are two types which are straight pipes thread and tapered pipes thread.
Common pipe threads mainly include the following types: NPT, PT, G, etc.

NPT thread picture

NPT thread picture

1) NPT is the abbreviation of National (American) Pipe Thread, which belongs to the American standard 60-degree tapered pipe thread and is used in North America. Refer to GB/T12716-1991 for the national standard.

2) PT (BSPT) is the abbreviation of Pipe Thread. It is a 55-degree sealed tapered pipe thread. It belongs to the Wyeth thread family. It is mostly used in Europe and the Commonwealth countries. It is often used in the water and gas pipe industry. The taper is 1:16. Refer to GB/ T7306-2000. The domestic name is ZG.

3) G is a 55-degree non-sealed pipe thread, which belongs to the Wyeth thread family. Marked as G stands for cylindrical thread. Refer to GB/T7307-2001 for the national standard.

Metric and inch threads

Metric threads are expressed by pitch, while American and British threads are expressed by the number of threads per inch;

Metric thread is 60-degree equilateral profile, inch thread is isosceles 55-degree profile, and American thread is isosceles 60-degree profile;

Use metric units (such as mm) for metric threads, and use imperial units (such as inches) for American and British threads;

“Insiders” usually use “minutes” to refer to the thread size, one inch equals 8 points, 1/4 inch equals 2 points, and so on.

In addition, there are: ISO—Metric Thread Standard 60°; UN—Unified Thread Standard 60°; API—American Petroleum Pipe Thread Standard 60°; W—British Wyeth Thread Standard 55°.

The difference between various threads

NPT, PT, G  are all pipe threads.

NPT is the abbreviation of National (American) Pipe Thread, which belongs to the American standard 60-degree tapered pipe thread and is used in North America. National standards can be found in GB/T12716-1991

PT is the abbreviation of Pipe Thread. It is a 55-degree sealed tapered pipe thread. It belongs to the Wyeth thread family and is mostly used in Europe and Commonwealth countries. Commonly used in water and gas pipe industry, the taper is 1:16. National standards can be found in GB/T7306-2000

G is a 55-degree non-thread sealed pipe thread, which belongs to the Wyeth thread family. Marked as G stands for cylindrical thread. National standards can be found in GB/T7307-2001

In addition, the 1/4, 1/2, and 1/8 marks in the thread refer to the diameter of the thread size, and the unit is inch. Insiders usually use points to refer to the thread size, one inch equals 8 points, 1/4 inch equals 2 points, and so on. G is the general name of pipe thread (Guan). The division of 55 and 60 degrees is functional, commonly known as pipe circle. That is, the thread is processed by a cylindrical surface.

ZG is commonly known as pipe cone, that is, the thread is processed by a conical surface. The general water pipe joints are like this. The national standard is marked as Rc metric thread to indicate the pitch, and the American thread is 60 degrees. Metric units are used for metric threads, and imperial units are used for American and British threads. Pipe thread is mainly used to connect pipelines. The internal and external threads are closely matched. There are two types of straight pipes and tapered pipes. The nominal diameter refers to the diameter of the connected pipe, obviously the thread diameter is larger than the nominal diameter. 1/4, 1/2, 1/8 are the nominal diameters of inch threads, and the unit is inches.

Inch pipe threads are derived from British Wyeth threads. The combination of Wyeth threaded pipe series and Wyeth thread profiles establishes the basic dimensions of British pipe threads. According to the 1/16 taper relationship, the radial diameter tolerance of Wyeth threads is converted into British sealed tubes. Tolerance of the axial number of threads (there is a certain amount of rounding and adjustment). Then refer to the tolerance value of the inch seal pipe thread to propose the tolerance of the inch unsealed pipe thread (the tolerance changes from one-way distribution to one-way distribution, relax the top Diameter tolerance, let go of the bottom diameter tolerance). The time for the three types of threads is:

In 1841, the British Wyeth thread was proposed, and in 1905, the new Wyeth thread standard (BS 84) was promulgated.

In 1905, the British Sealed Pipe Thread Standard (BS 21) was promulgated.

From 1905 to 1940, Wyeth Thread performed the responsibility of the imperial unsealed pipe. In 1940, the unsealed pipe thread series (BSP series) of Wyeth Thread was proposed; in 1956, the British unsealed pipe thread standard (BS 2779) was issued separately.

European countries and Commonwealth countries first accepted the imperial pipe thread standard. The ISO/TC5/SC5 Pipe Thread Standardization Technical Committee and its secretariat are controlled by European countries, and the imperial pipe thread standard was adopted by the ISO standard. In 1955, the ISO proposed the imperial sealed pipe thread Standard (ISO R 7); In 1961, ISO proposed the standard for imperial unsealed pipe threads (ISO R 228). In 1978, ISO promulgated two official standards for imperial pipe threads (ISO7-1 and ISO228-1). Threads have been generally accepted by countries outside North America and are widely used in international trade.

The inch pipe thread in the ISO standard has been converted to the metric system. The metric method of the inch pipe thread is very simple. Multiply the inch size of the original pipe thread by 25.4 to convert it to the millimeter size. The inch pipe thread size is being eliminated. The so-called use of real pipe thread standards is unrealistic. There is no distinction between real metric pipe threads and fake metric pipe threads.

Resilient seated socket end gate valve

GATE VALVE-resilient seated SOCKET END
Standard: EN1074; EN1171

Socket ended resilient seated wedge gate valve-ductile iron (1)

Socket ended resilient seated wedge gate valve-ductile iron (1)

CAST IRON / DUCTILE IRON GATE VALVE SOCKET END
NON RISING STEM
Pressure: PN10 / PN16
Connection ends: Socked ends, for PVC pipes, uPVC pipes
FACE TO FACE: ACCORDING TO BS, DIN, ANSI, AWWA, SABS STANDARD ETC.
BODY:CAST IRON/DUCTILE IRON
BONNET:CAST IRON/DUCTILE IRON
WEDGE:CAST IRON/DUCTILE IRON, fully vulcanized with EPDM rubber
STEM: SS/BRASS
Coating: fusion bonded expoxy coating

The opening and closing part of the socket gate valve is a gate. The movement direction of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled. The gate has two sealing surfaces. The two sealing surfaces of the most commonly used mode gate valve form a wedge. The wedge angle varies with valve parameters, usually 50, and 2°52′ when the medium temperature is not high. The gate of the wedge gate valve can be made into a whole, called a rigid gate; it can also be made into a gate that can produce slight deformation to improve its manufacturability and compensate for the deviation of the sealing surface angle during the processing. The plate is called an elastic gate.

Socket gate valve can be divided into wedge gate valve and parallel gate valve according to the sealing surface configuration. The wedge gate valve can be divided into: single gate, double gate and elastic gate; parallel gate valve can be divided into It is single gate type and double gate type. According to the thread position of the valve stem, it can be divided into two types: rising stem gate valve and non-rising stem gate valve.

When the socket gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, rely on the medium pressure to press the sealing surface of the gate against the valve seat on the other side to ensure the sealing of the sealing surface, which is self-sealing. Most gate valves use forced sealing, that is, when the valve is closed, the gate must be forced against the seat by external force to ensure the sealing performance of the sealing surface.

The gate of the socket gate valve moves linearly with the valve stem, which is called rising stem gate valve (also called rising stem gate valve). Usually there is a trapezoidal thread on the lifting rod, through the nut on the top of the valve and the guide groove on the valve body, the rotary motion is changed into linear motion, that is, the operating torque is changed into operating thrust.

When the valve is opened, when the lifting height of the gate is equal to 1:1 times the valve diameter, the fluid passage is completely unblocked, but this position cannot be monitored during operation. In actual use, the apex of the valve stem is used as a mark, that is, the position where it cannot be opened, as its fully open position. In order to take into account the locking phenomenon of the temperature change, it is usually at the top position of the opening, and then rewind 1/2-1 turn as the position of the fully open valve. Therefore, the fully open position of the valve is determined by the position of the gate (that is, the stroke).

Socket ended resilient seated wedge gate valve-ductile iron (2)

Socket ended resilient seated wedge gate valve-ductile iron (2)

In some gate valves, the stem nut is set on the gate, and the rotation of the handwheel drives the rotation of the valve stem to lift the gate. This kind of valve is called a rotating stem gate valve or a dark stem gate valve.

advantage:
The fluid resistance is small, and the sealing surface is less brushed and corroded by the medium.
It is easier to open and close.
The flow direction of the medium is not restricted, does not disturb the flow, and does not reduce the pressure.
The shape is simple, the length of the structure is short, the manufacturing process is good, and the scope of application is wide.

Disadvantages:
It is easy to cause erosion and scratches between the sealing surfaces, which makes maintenance difficult.
The overall size is large, opening requires a certain amount of space, and the opening and closing time is long.
The structure is more complicated.

The types of socket gate valves can be divided into wedge gate valves and parallel gate valves according to the sealing surface configuration. Wedge gate valves can be divided into: single gate type, double gate type and elastic gate type; parallel gate type Gate valves can be divided into single gate type and double gate type. Divided according to the thread position of the valve stem, it can be divided into two types: open stem gate valve and dark stem gate valve.

Matters needing attention in installation and maintenance
Handwheels, handles and transmission mechanisms are not allowed to be used for lifting, and collisions are strictly prohibited.
The double gate valve should be installed vertically (that is, the valve stem is in the vertical position and the handwheel is at the top).
The gate valve with bypass valve should be opened before opening (to balance the pressure difference between inlet and outlet and reduce the opening force).
The gate valve with transmission mechanism should be installed according to the product manual.
If the valve is frequently opened and closed, lubricate at least once a month.

Structural features:
The general gate valves used on the market for a long time generally have water leakage or rust. The company introduces the elastic seat seal gate valve produced by European high-tech rubber and valve manufacturing technology, which overcomes the defects of poor sealing and rust of general gate valves. The sealing gate valve uses the compensation effect of the elastic gate plate to produce a small amount of elastic deformation to achieve a good sealing effect. The valve has the obvious advantages of light switch, reliable sealing, good elastic memory and service life. It can be widely used as a regulating and intercepting device on the pipelines of tap water, sewage, construction, petroleum, chemical industry, food, medicine, textile, electric power, shipbuilding, metallurgy, energy system, etc.

 

Types and classifications of gate valves

Gate valve, also called plate gate valve, is mainly composed of valve body, bonnet, disc, valve stem, valve seat and sealing packing. It is one of the most common valve types in isolation valves. The main purpose of the gate valve is to cut off the fluid. For this reason, it is usually called a “cut off” valve or a “blocking” valve. The gate valve has many different structural forms, and the sealing element structure used in it is different. According to the structure of the sealing element, it can be divided into several different types.

ductile iron soft seal gate valve-non rising stem

ductile iron soft seal gate valve-non rising stem

Classified by valve stem:
According to the stem type, it can be divided into rising-stem gate valve and non rising-stem gate valve. The valve stem is the operating part of the gate valve, and its function is to transmit the opening and closing force to the opening and closing parts.
1. The trapezoidal thread of the rising-stem gate valve is placed outside the valve body and located on the upper part of the valve stem. By rotating the valve stem nut, the valve stem drives the disc to rise and fall synchronously to realize the opening and closing of the valve, so it is easy to identify the valve The opening and closing state of the machine can avoid misoperation. Since the stem nut is outside the body cavity, it is beneficial to lubrication, and the opening and closing state is intuitive and obvious, so it is widely used. However, in harsh environments, the exposed threads of the valve stem are vulnerable to damage and corrosion, even affecting operation. Its disadvantage is that the height of the valve after opening is large, usually a stroke is added to the original height of the valve, which requires a lot of operating space.

rising stem gate valve-OS&Y (3)

rising stem gate valve-OS&Y (3)

2. Non rising-stem gate valve is also called rotating stem gate valve (also called non rising-stem wedge gate valve). The stem nut is placed inside the valve body and is in direct contact with the medium and is often fixed on the disc. Through the rotation of the valve stem, the valve stem nut drives the disc to move up and down to complete the opening and closing. Usually there is a trapezoidal thread at the bottom end of the valve stem. Through the thread at the bottom end of the valve and the guide groove on the valve disc, the rotary motion is changed into linear motion, that is, the operating torque is turned into operating thrust. Since the trapezoidal thread for transmission is located inside the valve body, it is easily corroded by the medium and cannot be lubricated. The opening degree cannot be directly observed, and an indicating device is required. However, its valve stem does not move up and down, and requires small operating space, so it is suitable for occasions with limited locations and dense pipelines.

Classified by structure:
According to the structure type, it can be divided into two types: wedge gate valve and parallel gate valve. That is, the disc is a wedge type is called a wedge gate valve, and the disc is a parallel type is a flat gate valve.
1. The flat gate valve means that the sealing surface is parallel to the vertical centerline, so the sealing surfaces on the valve body and the disc are also parallel to each other. The most common type of this kind of gate valve is the double disc type. In order to make the valve body and the two sealing surfaces of the disc tightly contacted when it is closed, a double-sided thrust wedge is often used between the two discs. It is mostly used in low pressure pipelines such as small pipelines. Parallel gate valves using a single disc are also available but rare.
2. Wedge gate valve means that the sealing surface is at a certain angle with the vertical center line, that is, the two sealing surfaces are wedge-shaped gate valves. The disc of wedge gate valve is single and double. The advantage of the double disc type is that the accuracy of the sealing angle is lower, the temperature change is not easy to make the disc wedged, and the sealing surface wear can be compensated with gaskets. The disadvantage is that the structure is complex, and it is easy to stick in dry media, and the main reason is that the disc is easy to fall off after the upper and lower baffles are rusted for many years.

non-rising stem gate valve-open and close position

non-rising stem gate valve-open and close position

rising stem gate valve-open and closed position

rising stem gate valve-open and closed position

Classification by other methods:
According to different standards: national standard gate valve, American standard gate valve, German standard gate valve, Japanese standard gate valve
According to the connection method: flange gate valve, welded gate valve, threaded gate valve (divided into internal thread and external thread)
According to pressure level: high pressure gate valve, low (medium) pressure gate valve
According to the driving mode: electric gate valve, pneumatic gate valve, manual gate valve
Classified by material: stainless steel gate valve, forged steel gate valve, cast steel gate valve, carbon steel gate valve, cast iron gate valve, copper gate valve (also divided into bronze gate valve, brass gate valve), ceramic gate valve, plastic gate valve

The main difference:
1. The lifting screw of the concealed rod flange gate valve only rotates and moves up and down. Only a rod is exposed. The screw cap is fixed on the disc. The disc is raised by the rotation of the screw, and there is no visible electric gate valve frame. ; The lifting screw of the rising stem flange gate valve is exposed, and the screw cap is close to the hand wheel and is fixed (not high-pressure gate valve rotation nor axial movement), the disc is improved by rotating the screw, the screw and the disc have only relative rotational movement There is no relative axial displacement, and the appearance is a gate-shaped bracket.
2. The valve stem with dark stem cannot be seen, while the stem with open stem can be seen.
3. The steering wheel and the valve stem are connected and relatively immovable when the dark stem valve is opened and closed. The valve stem rotates at a fixed point to help the valve clack move upward and downward to complete the opening and closing. The rising stem valve is driven by the turnbuckle of the valve stem and the steering wheel to raise or lower the disc.
To put it simply, the rising stem valve is that the disc and the stem move up and down together, and the steering wheel is always at a fixed point.
Is rising-stem gate valve or non rising-stem gate valve used outdoors?
For the valves installed in the outdoor valve wells, according to the experience of Tanghai valves, it is recommended that you use dark stem valves. The use of rising stem valves has the following disadvantages: 1. When the valve is opened and closed, the valve stem has to rise and fall, which takes up a lot of space. If the pipeline is not buried very deep, the valve well will hinder the opening of the valve. When the valve is opened, the valve well cover will not be closed or the valve cannot be fully opened. 2. After the number of switches is increased, the contact surface of the valve stem and the pressure flange will leak more seriously, and the packing should be replaced frequently. 3. If you don’t switch frequently, a part of the valve stem will be exposed to the valve body for a long time. In the humid environment of the valve well, the exposed valve stem is very easy to oxidize and rust. Once it needs to be closed, it will not be closed. Otherwise, grease must be applied frequently. In short, the maintenance workload is large. Dark stem valves do not have these problems, the probability of water leakage is also small, and of course the maintenance workload is also small. for reference only.

The opening and closing part of the rising-stem gate valve (gate valve) is a disc, and the movement direction of the disc is perpendicular to the direction of the fluid. The rising-stem gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled.

Disc has two sealing surfaces. The two sealing surfaces of the most commonly used mode disc valve form a wedge. The wedge angle varies with valve parameters, usually 50, and 2°52′ when the medium temperature is not high. The disc of the wedge gate valve can be made into a whole, called a rigid disc; it can also be made into a disc that can produce slight deformation to improve its manufacturability and make up for the deviation of the sealing surface angle during the processing. This disc is called an elastic disc .

The types of rising-stem gate valve can be divided into wedge disc gate valve and parallel disc gate valve according to the sealing surface configuration. Wedge disc gate valve can be divided into: single disc type, double disc type and elastic disc type; parallel disc Type gate valve can be divided into single disc type and double disc type. According to the thread position of the valve stem, it can be divided into rising-stem gate valve and non rising-stem gate valve.

When the rising-stem gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, only rely on the medium pressure to press the sealing surface of the disc to the valve seat on the other side to ensure the sealing of the sealing surface, which is self-sealing. Most gate valves adopt forced sealing, that is, when the valve is closed, the disc must be forced to the valve seat by external force to ensure the tightness of the sealing surface.
The working principle of rising-stem gate valve
Rotate the hand wheel, through the advance and retreat of the thread of the hand wheel and the valve stem, raise or lower the valve plate connected with the valve stem to open and close
The rising-stem gate valve has the following advantages:
The fluid resistance is small, and the sealing surface is less eroded and eroded by the medium.
It is easier to open and close.
The flow direction of the medium is not restricted, does not disturb the flow, and does not reduce the pressure.
The shape is simple, the length of the structure is short, the manufacturing process is good, and the scope of application is wide.
The disadvantages of rising-stem gate valve are as follows:
It is easy to cause erosion and scratches between the sealing surfaces, and maintenance is difficult.
The overall size is large, opening requires a certain amount of space, and the opening and closing time is long.
The structure is more complicated.
The types of gate valves can be divided into wedge disc gate valves and parallel disc gate valves according to the sealing surface configuration. Wedge disc gate valves can be further divided into: single gate, double disc and elastic disc; parallel disc gate valves can be Divided into single disc type and double disc type. According to the thread position of the valve stem, it can be divided into rising-stem gate valve and non rising-stem gate valve.
Installation and maintenance of rising-stem gate valve:
Handwheels, handles and transmission mechanisms are not allowed to be used for lifting, and collisions are strictly prohibited.
The double disc gate valve should be installed vertically (that is, the valve stem is in the vertical position and the handwheel is at the top).
The gate valve with a bypass valve should be opened before opening (to balance the pressure difference between the inlet and outlet and reduce the opening force).
The gate valve with transmission mechanism should be installed according to the product manual.
If the valve is frequently opened and closed, lubricate at least once a month.

Structural characteristics of rising-stem gate valve:
The general gate valves used on the market for a long time generally have water leakage or rust. The company introduces the elastic seat seal gate valve produced by European high-tech rubber and valve manufacturing technology, which overcomes the defects of poor sealing and rust of general gate valves. The sealing gate valve uses the compensation effect of the elastic disc to produce a small amount of elastic deformation to achieve a good sealing effect. The valve has the obvious advantages of light switch, reliable sealing, good elastic memory and service life. It can be widely used as a regulating and intercepting device on the pipelines of tap water, sewage, construction, petroleum, chemical industry, food, medicine, textile, electric power, shipbuilding, metallurgy, energy system, etc.

Features of rising-stem gate valve:
Light weight: The body is made of high-grade ductile iron, which is about 20% to 30% lighter than the traditional gate valve, and is easy to install and maintain.

Flat-bottomed gate seat: The traditional gate valve often deposits in the groove at the bottom of the valve due to foreign objects such as stones, wood, cement, iron filings, and other debris after the pipe is washed with water. The bottom of the elastic seat-sealed gate valve adopts the same flat-bottom design as the water pipe machine, which is not easy to cause debris siltation and makes the fluid flow unimpeded.

Integral encapsulation: The disc adopts high-quality rubber for the overall inner and outer rubber. European first-class rubber vulcanization technology enables the vulcanized disc to ensure accurate geometric dimensions, and the rubber and ductile disc are connected firmly, not easy to fall off, and have good elastic memory . water

Precision casting valve body: The valve body adopts precision casting, and the precise geometric dimensions make the inside of the valve body without any finishing to ensure the sealing of the valve.
Features of dark-rod soft-seal gate valve:
The overall valve encapsulation is used to produce a deformation compensation effect to achieve a good sealing effect, overcome the poor sealing, water leakage and rust of the general gate valve, and save installation space more effectively. It can be widely used in tap water, sewage, construction, petroleum, chemical, It is used as a regulating and intercepting device on fluid pipelines such as food, medicine, textile, electric power, shipbuilding, metallurgy, energy systems. Our factory introduces European high-tech valve manufacturing technology to produce elastic seat-sealed gate valves, which are deformed by the overall encapsulation of the gate. The compensation effect achieves a good sealing effect and overcomes the phenomenon of poor sealing, water leakage and rust of general gate valves. It can be widely used as a regulating and intercepting device on fluid pipelines such as tap water, sewage, construction, petroleum, chemical industry, food, medicine, minor injuries, electric power, ships, metallurgy, and energy systems.
1. The gate adopts integral rubber encapsulation, and its good covering performance and precise geometric dimensions ensure reliable sealing and longevity.
2. Light weight: The valve body is made of ductile iron, which is light in weight and easy to install.
3. Flat-bottomed valve seat: The bottom is designed with the same flat-bottomed valve seat as the water pipe, which does not produce debris and makes the seal more reliable.
4. Corrosion resistance: The inner cavity is coated with non-toxic epoxy resin to prevent corrosion and rust. Not only can it be used for raw drinking, but also can be used in sewage systems.
5. Three “0” seal: The valve stem is sealed with three O-rings, with low friction resistance, light switch and no water leakage.
How to select the non rising-stem gate valve and rising-stem gate valve?
For oil and natural gas pipelines, single disc or double disc gate valves are used. If you need to clean the pipeline, use a single disc or double disc rising-stem gate valve with diversion holes.
For the transportation pipeline and storage equipment of refined oil, select single disc or double disc gate valve without diversion hole.
For oil and natural gas mining wellhead devices, single disc or double disc gate valves with dark rod floating valve seats and diversion holes are selected, most of which are API16A standards, and the pressure levels are API2000, API3000, API5000, API10000, API15000, API20000.
For pipelines with suspended particulate media, use knife-shaped plate gate valves.
The city gas transmission pipeline adopts single disc or double disc soft-sealed rising-stem gate valve.
For urban tap water projects, single disc or double disc rising-stem gate valve without diversion hole is used.

Valve material comparison table-valve pressure-temperature

The relationship between valve temperature and pressure:
The valve operating temperature and pressure have a certain internal connection and influence each other. Among them, temperature is the dominant factor affecting the valve. A valve with a certain pressure is only suitable for a

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

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

certain temperature range, and changes in valve temperature can affect the valve’s operating pressure. E.g:
The nominal pressure of a carbon steel valve is 10MPa. When the medium working temperature is 200℃, its maximum working pressure P20 is 10MPa; when the medium working temperature is 400℃, its maximum working pressure P40 is 5.4MPa; when the medium works When the temperature is 450℃, the maximum working pressure P20 is 4.5MPa.

Valve material temperature and pressure comparison table:
Valve material and applicable pressure, temperature and grade
Gray cast iron is suitable for water, steam, air, gas, oil and other media with nominal pressure PN≤1.0MPa and temperature -10℃~200℃. Commonly used grades are: HT200, HT250, HT300, HT350.
Malleable cast iron Suitable for water, steam, air and oil media with nominal pressure PN≤2.5MPa and temperature -30~300℃. Commonly used grades are: KTH300-06, KTH330-08, KTH350-10.
Nodular cast iron is suitable for water, steam, air and oil with PN≤4.0MPa and temperature of -30~350℃. Commonly used grades are: QT400-15, QT450-10, QT500-7. At present, the level of domestic technology varies among factories, and it is often difficult for users to inspect. It is recommended that PN≤2.5MPa, and steel valves are used for safety.
Acid-resistant high-silica ductile iron Suitable for nominal pressure PN≤0.25MPa, suitable for corrosive media with temperature lower than 120℃.
Carbon steel is suitable for water, steam, air, hydrogen, ammonia, nitrogen and petroleum products with a nominal pressure of PN≤32.0MPa and a temperature of -30~425℃. Commonly used grades are WC1, WCB, ZG25, high-quality steel 20, 25, 30 and low-alloy structural steel 16Mn.
Copper alloy is suitable for water, sea water, oxygen, air, oil and other media with PN≤2.5MPa and steam media with temperature of -40~250℃. Commonly used grades are ZGnSn10Zn2 (tin bronze), H62, Hpb59-1 (brass) , QAZ19-2, QA19-4 (aluminum bronze).
High-temperature copper is suitable for steam and petroleum products with nominal pressure PN≤17.0MPA and temperature≤570℃. The specific selection must be in accordance with the valve pressure and temperature specifications. Commonly used grades are ZGCr5Mo, 1Cr5M0.ZG20CrMoV, ZG15Gr1Mo1V, 12CrMoV, WC6, WC9, etc.
Low-temperature steel is suitable for media with nominal pressure PN≤6.4Mpa and temperature≥-196℃ ethylene, propylene, liquid natural gas, liquid nitrogen, etc. Commonly used grades are ZG1Cr18Ni9, 0Cr18Ni9, 1Cr18Ni9Ti, ZG0Cr18Ni9
Stainless and acid-resistant steel Suitable for media such as nitric acid and acetic acid with nominal pressure PN≤6.4Mpa and temperature≤200℃. Commonly used grades are ZG0Cr18Ni9Ti, ZG0Cr18Ni10<nitric acid>, ZG0Cr18Ni12Mo2Ti, ZG1Cr18Ni12Mo2Ti<acid and urea>

Valve seal (ring) material usage range comparison table

The selection of valve sealing material is determined according to the operating conditions of the valve, such as: pipeline medium, temperature range (high and low temperature), pressure and internal structure of the valve. For

soft sealing marine valve, rubber sealing, valve seat parts

soft sealing marine valve, rubber sealing, valve seat parts

different occasions, the selected seals are also different. Valve seals can generally be divided into two categories: soft seals and hard seals. Users should have a detailed understanding of their codes, operating temperature, pressure, medium and other parameters.

Comparison table of valve sealing material usage range:
Valve sealing material and valve sealing material use range:
Rubber (X) Nominal pressure PN ≤ 1 MPa, operating temperature t ≤ 150℃, applicable valves: globe valves, diaphragm valves, butterfly valves, check valves, etc.
Nylon (N) Nominal pressure PN ≤ 32 MPa, operating temperature t ≤ 90°C, applicable valves: globe valves, ball valves, etc.
PTFE (F) Nominal pressure PN ≤ 6.4 MPa, operating temperature t ≤ 180°C, applicable valves: globe valves, ball valves, gate valves, diaphragm valves, butterfly valves, check valves, etc.
Bus alloy (B) Nominal pressure PN ≤ 2.5 MPa, operating temperature t ≤ 150°C, applicable valves: stop valves for ammonia, etc.
Ceramic (G) Nominal pressure PN ≤ 1.6 MPa, operating temperature t ≤ 150°C, applicable valves: ball valves, plug valves, etc.
Enamel (C) Nominal pressure PN ≤ 1.0 MPa, operating temperature t ≤ 80°C, applicable valves: globe valve, diaphragm valve, check valve, discharge valve, etc.
Copper alloy (T) Nominal pressure PN ≤ 1.6 MPa, operating temperature t ≤ 200℃, applicable valves: gate valve, globe valve, check valve, plug valve, etc.
Stainless steel (H) Nominal pressure PN ≤ 32 MPa, operating temperature t ≤ 450°C, applicable valves: globe valves, ball valves (medium and high pressure valves), etc.
Nitrided steel (D) Nominal pressure PN ≤ 10 MPa, operating temperature t ≤ 540℃, applicable valves: power station gate valves, only for general use
Cemented carbide (Y) Nominal pressure (PN) and operating temperature (t) are determined according to the material of the valve body. Applicable valves: high pressure, ultra high pressure valves, high temperature and low temperature valves