What is a valve? This is now the definition of the valve, the valve is the control component of the fluid delivery system, with diversion, closure, regulation, throttling, prevent backflow, diversion or overflow pressure relief and other functions. As an important control element of pipelines, valves are widely used in various sectors of the national economy such as petroleum, chemical, metallurgy, natural gas transmission, power stations, and urban water supply.

Below, we further introduce the valve knowledge.

1.DN (nominal size)

The following nominal size DN values ​​are based on the GB/T 1047-2004 standard.

DN: Dimensional identification of combinations of letters and numbers used for pipe system components. It consists of the letters DN and followed by the non-dimensional integer numbers. This number is directly related to the feature size such as the hole diameter or outer diameter (unit: mm) of the end connector.

Note:

Unless otherwise specified in the relevant standards, the numbers following the letters DN do not represent measured values ​​and cannot be used for calculation purposes.

Those standards that use the DN logo system should give the relationship of the DN to the dimensions of the pipe components, such as DN/OD or DN/ID.

The preferred DN values ​​are as follows:

DN6 DN100 DN700 DN2200

DN8 DN125 DN800 DN2400

DN10 DN150 DN900 DN2600

DN15 DN200 DN1000 DN2800

DN20 DN250 DN1100 DN3000

DN25 DN300 DN1200 DN3200

DN32 DN350 DN1400 DN3400

DN40 DN400 DN1500 DN3600

DN50 DN450 DN1600 DN3800

DN65 DN500 DN1800 DN4000

DN80 DN600 DN2000

2.PN (nominal pressure)

The following nominal pressure PN values ​​are based on the GB/T 1048-2004 standard.

PN: Identification of combinations of letters and numbers used for reference in relation to the mechanical properties and dimensional properties of pipe system components. It consists of the letter PN followed by the dimensionless number.

Note:

The numbers following the letter PN do not represent measured values ​​and should not be used for calculation purposes unless otherwise specified in the relevant standards.

The term PN does not make sense except when it relates to related fitting standards.

The piping component allowable pressure depends on the PN value, material and design of the component, and the allowable operating temperature, etc., allowing the pressure to be given in the corresponding standard pressure-temperature register.

All pipe elements with the same PN and DN values ​​should have the same mating dimensions as the flanges that match them.

The PN value should be selected from the following families:

PN DIN Series ANSI Series PN2.5 PN20

PN6 PN50

PN10 PN110

PN16 PN150

PN25 PN260

PN40 PN420

PN63

PN100

Note: Other PN values ​​are allowed when necessary.

3 valve model preparation method

The valve model preparation method is mainly based on the JB/T 308-2004 standard.

(1) Modeling method:

Model preparation method IIIIIIIVV-VIVIII

I: type code II: drive method code III: connection form code IV: structure form code V: sealing surface material or lining material code VI: working pressure under pressure code or working temperature VII: valve body material code (2) valve type Codes are expressed in Hanyu Pinyin and are stipulated in Table 1, Table 2 and Table 3.

Table 1 Valve Type Code Valve Type Code Valve Type Code Safety Valve A Ball Valve Q

Butterfly Valve D Trap Valve S

Diaphragm valve G Regulator T

Check Valve H Plunger Valve U

Shutoff Valve J Plug Valve X

Throttle valve L Pressure relief valve Y

Drain valve P Gate valve Z

"Table 2" has other functions. The symbol for the valve indicates the second function. The name of the code is for the second function. The name of the code is for low temperature type D.

Insulation type B slagging type P

Bellows Type W Purge Type C

Telescopic flange type S Fireproof type F

V-ball type V fast type Q

"Table 3" Characters with specific structural valves Code-specific structure name Code-specific structure name Code knife Flat gate valve D Water seal type S

Vented gate valve K without diversion gate valve W

(3) The drive code is represented by Arabic numerals, as specified in Table 4.

"Table 4" drive way code drive mode code drive code electromagnetic 0 bevel gear 5

Electro-hydraulic 1 pneumatic 6

Electro-hydraulic 2 hydrodynamic 7

Turbine 3 gas - hydraulic 8

Spur gear 4 electric 9

Note:

Code 1, code 2 and code 8 are used when the valve is opened and closed. Two power sources are required to operate the valve at the same time.

Safety valves, hydraulic valves, water delivery valves, and manual handwheels are directly connected to valves in the form of valve stem operating structures. This designation omitted not to be indicated.

For pneumatic or hydraulic motion: normally open type is indicated by 6K and 7K; normally closed type is indicated by 6B, 7B; pneumatic type is indicated by manual 6S; explosion-proof electric type is indicated by 9B.

(4) The connection form code is represented by Arabic numerals according to the "Table 5".

"Table 5" connection form code connection form code connection form code female thread 1 welding 6b

External thread 2 pairs 7

Flange 4 clip 8

Socket welding 6s card sleeve 9

(5) The valve structure type code is represented by Arabic numerals, according to the provisions of "Table 6" to "Table 16".

"Table 6" Gate Valve Structure Code Structure Structure Code Light Wedge Flexible Gate 0

Rigid gate single gate 1

Double gate 2

Parallel type single gate 3

Double gate 4

Dark rod wedge single gate 5

Double gate 6

Parallel single gate 7

Double gate 8

"Table 7" Closing valve, throttle valve and plunger valve Structure Code Structure Structure Code Structure Structure Code Feedthrough 1 DC 5

Z Form 2 Balanced Straight-through 6

Three general formula 3 angle 7

Angle 4

"Table 8" Ball Valve Structure Code Structure Structure Code Structure Code Floating Ball Feedthrough 1 Fixed Ball Feedthrough 7

Y-shaped three-way 2 four 6

L shaped 4 T shaped triangular 8

T shaped 5 L shaped 9

Hemisphere direct 0

"Table 9" Ball Valve Structure Code Structure Structure Code Structure Code Seal Type Midline Type 1 Non-hermetic Midline Type 6

Double eccentric 2 double eccentric 7

Three eccentric 3 three eccentric 8

Linkage mechanism 4 Linkage mechanism 9

"Table 10" Diaphragm Valve Structure Code Structure Structure Code Structure Type Code Roof 1 Straight-through 6

Cut-off 3 angle Y shape 8

DC 5

"Table 11" Structure of plug valve Structure Code Structure Code Structure Code Sealing Straight-through 3 Oil Seal Straight-through 7

T-shaped tri-type 4 T-shaped tri-type 8

Four general formula 5

"Table 12" Check Valve Structure Code Structure Structure Code Structure Code Lifting Straight-through Rotary Type Single-Valve 4

Multi-valve 5

Double flap type 6

Vertical 2 butterfly check back 7

Angle 3 cut-off check 8

Table 13 Safety Valve Structure Code Structure Structure Code Structure Code Spring Seal with Heat Sinks Full Start Type 0 Spring Unsealed with Wrench Double Springs 3

Micro-switching type 1 micro-switching type 7

Full Kai 2 Full Kai 8

Wrench-whole-start type 4 with control mechanism WK6

Lever type 5 pulse 9

Table 14 Relief Valve Structure Code Structure Structure Code Structure Code Thin Film Type 1 Bellows Type 4

Spring film type 2 Lever type 5

Piston 3

Table 15 Steam Trap Structure Code Structure Structure Code Structure Code Float 1 Steam Pressure or Membrane Box 6

Float barrel type 3 bimetal type 7

Liquid or solid expansion type 4 pulse 8

Bell Float 5 Disc Thermodynamic Type 9

"Table 16" Drain Valve Structure Code Structure Structure Code Structure Code Liquid Connection Discharge Cut-off Straightness 1 Liquid Discontinuation Discharge Cut-off DC 5

Cut-through straight-through 6

Cutoff Angle 2 Cutoff Angle 7

Floating Gate Type 8

(6) The seal surface or lining material code is represented by the English alphabet, as specified in Table 17.

"Table 17" sealing surface or lining material code sealing surface or lining material code sealing surface or lining material code Tin-base bearing alloy (Babbs) B nylon plastic N

Enamel C Boron Boron Steel P

Nitriding Steel D Leaded Q

Fluoroplastic F Austenitic Stainless Steel R

Ceramic G Plastic S

Cr13 Series Stainless Steel H Copper Alloy T

Rubber lining J Rubber X

Monel M Carbide Y

Note:

In addition to the diaphragm valve, when the material of the sealing surface of the sealing pair is different, it is expressed as a hard density material.

When the valve sealing auxiliary material is the body material of the valve, the material designation of the valve seat sealing surface is indicated by "W".

(7) Valve nominal pressure, according to GB/T 1048-2005.

Valves used in power station industry are marked with working pressure at the highest working temperature when the maximum temperature of the medium exceeds 425°C.

The pressure level shall be in Lb or (K) class units. In the model establishment, there shall be a unit symbol Lb or K after the pressure code column.

(8) The valve body material code is represented by the English alphabet, according to "Table 18".

"Table 18" Valve Body Material Code Body Material Code Valve Body Material Code Carbon Steel C Ductile Iron Q

Cr13 stainless steel H 0Cr17Ni12Mo2 stainless steel R

1Cr5Mo Chrome Molybdenum Steel I 0Cr17Ni14Mo2 Stainless Steel RL

15CrMo Chrome Molybdenum Steel H Plastic S

Malleable Cast Iron K Copper and Copper Alloy T

Aluminum alloy L titanium and titanium alloy Ti

0Cr18Ni9 Stainless Steel P Chrome Molybdenum Vanadium Steel V

0Cr19Ni10 Stainless Steel PL Gray Cast Iron Z

(9) Named:

For connections in the form of "Flange" and the structural forms are: "Plumble", "Elastic", "Rigid" and "Single Gate" of the gate valve, "Straight-opening" of the stop valve, throttle valve, and "Floating" of the ball valve "Ball" and "straight-through", "vertical plate" of butterfly valve, "roof type" of diaphragm valve, "filler" and "straight-through" of plug valve, "straight-through" and "single-valve" of check valve, The "non-enclosed type" and "valve seat sealing surface material" of the safety valve are all omitted in the naming.

(10) Example of model and name preparation method:

1) Electric, flanged, and wedge-type double-sluice plate, valve seat sealing surface material directly processed by the valve body, nominal pressure PN1, valve body material is gray cast iron gate valve: Z942W-1 electric wedge type double gate plate gate valve .

2) Manual, external thread connection, floating straight-through, valve seat sealing surface material is fluorine plastic, nominal pressure PN40, valve body material is 1Cr18Ni9Ti ball valve: Q21F-40P external thread ball valve.

3) Pneumatic normally open, flanged, ridged structure and rubber lined, nominal pressure PN6, valve material is gray cast iron diaphragm valve: G6K41J-6 pneumatic normally open rubber lined diaphragm valve.

4) Hydraulic, flanged, vertical plate, valve seat sealing surface material is cast copper, valve sealing surface material is rubber, nominal pressure PN2.5, valve body material is gray cast iron butterfly valve: D741X-2.5 hydraulic butterfly valve .

5) Electric drive for welding connection, straight pass, valve seat sealing surface material for surfacing hard alloy, working temperature 540 °C, working pressure 17.0MPa, valve body material chromium molybdenum vanadium steel closing valve: J961Y-P54170V electric welding deadline valve.

4. Valve materials The following list of valve materials is based on the JB/T 5300-1991 standard.

Body material performance Valve body material Applicable to nominal pressure/MPa Applicable temperature/°C Applicable medium Gray cast iron ≤10-10~200 Water, steam, air, gas and oil etc. Medium Malleable cast iron ≤25-30~300 Water, steam, air And mediums such as oil ductile iron ≤40-30~350 water, steam, air and oil and other medium copper alloy ≤25-40~250 water, seawater, oxygen, air and oil and other media carbon steel ≤ 320-30 ~450 Water, Steam, Air, Hydrogen, Ammonia, Nitrogen, and Petroleum Products, etc. Medium High Temperature Steel ≤ 16 ≤ 550 Steam and Petroleum Products Low Temperature Steel ≤ 64 ≥ -196 Ethylene, Propylene, Liquid Natural Gas, and Liquid Nitrogen Medium Stainless Acid Resistant Steel ≤64≤200 Nitric acid, acetic acid and other media