Valve knowledge

What is a valve? The current definition of a valve is that it is a control component in a fluid delivery system, which has functions such as guiding, intercepting, regulating, throttling, preventing backflow, diverting or overflow pressure relief. Valves, as important control components of pipelines, are widely used in various sectors of the national economy such as petroleum, chemical, metallurgical, natural gas transportation, power plants, and urban water supply.

Next, we will further introduce valve knowledge.

Nominal size (DN)

The following nominal size DN values are in accordance with GB/T 1047-2004 standard

DN: A combination of letters and numbers used for size identification of pipeline system components. It consists of the letter DN followed by an dimensionless integer number. This number is directly related to the characteristic dimensions such as the aperture or outer diameter (unit: mm) of the end connector.

The preferred DN values are as follows

DN 6	DN 100	DN 700	DN 2200
DN 8	DN 125	DN 800	DN 2400
DN 10	DN 150	DN 900	DN 2600
DN 15	DN 200	DN 1000	DN 2800
DN 20	DN 250	DN 1100	DN 3000
DN 25	DN 300	DN 1200	DN 3200
DN 32	DN 350	DN 1400	DN 3400
DN 40	DN 400	DN 1500	DN 3600
DN 50	DN 450	DN 1600	DN 3800
DN 65	DN 500	DN 1800	DN 4000
DN 80	DN 600	DN 2000

Nominal pressure (PN)

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

PN: A combination of letters and numbers used for reference, related to the mechanical properties and dimensional characteristics of pipeline system components. It consists of the letter PN followed by dimensionless numbers

The PN value should be selected from the following series

DIN series	ANSI series
PN2.5	PN20
PN6	PN50
PN10	PN110
PN16	PN150
PN25	PN260
PN40	PN420
PN63
PN100

Note: Other PN values may be used if necessary

Method for valve model designation

1	2	3	4	5	－	6	7

1. Type code
2. Driver mode code
3. Connection form code
4. Structural form code
5. Code for sealing surface material or lining material
6. Pressure code or working pressure at operating temperature
7. Valve body material code

Valve type code

Valve Type	code name	Valve Type	code name
safety valve	A	ball valve	Q
butterfly valve	D	steam trap	S
diaphragm valve	G	control valve	T
check valve	H	plunger valve	U
globe valve	J	Plug valve	X
throttle valve	L	pressure relief valve	Y
drain valve	P	gate valve	Z

Representative code for valves with other functional functions

Second functional function name	code name	Second functional function name	code name
Low temperature type	D	Slow closing type	H
insulated	B	Slag discharge type	P
Bellows type	W	Blowing type	C
Expansion flange type	S	fireproof type	F
V-shaped spherical shape	V	Quick type	Q

Horn code for valves with unique structures

Specific structure name	code name	Specific structure name	code name
Knife type flat gate valve	D	Water sealed type	S
Gate valve with guide hole type	K	Non diversion hole gate valve	W

Driver mode code

Drive Type	code name	Drive Type	code name
electromagnetic	0	bevel gear	5
Electromagnetic hydraulic	1	pneumatic	6
Electro hydraulic	2	hydraulic	7
turbine	3	Pneumatic hydraulic	8
Spur gear	4	electric	9

Note: 1. Code 1, Code 2, and Code 8 are used for valve opening and closing, requiring two power sources to operate the valve simultaneously

2. Valves with valve stem operation structure directly connected to safety valves, hydraulic valves, water delivery valves, and manual handwheels are omitted from this code and do not represent

3. For pneumatic or hydraulic: normally open type is represented by 6K and 7K; The normally closed form is represented by 6B and 7B; Pneumatic belt is represented by 6S for manual operation, and 9B for explosion-proof electric operation

Connection form code

connection type	code name	connection type	code name
internal thread	1	Regarding welding	6b
external thread	2	Laminated Pancake	7
flange	4	clamp	8
socket weld	6s	card holder	9

Sealing surface or lining material code

Sealing surface or lining material	code name	Sealing surface or lining material	code name
Tin based bearing alloy (Babbitt alloy)	B	Nylon plastic	N
enamel	C	Boron infiltrated steel	P
Nitriding steel	D	Lined with lead	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 alloy	M	cemented carbide	Y

Note: 1. Except for diaphragm valves, when the sealing surface material of the sealing pair is different, it is represented by a hard density material

2. When the sealing auxiliary materials of the valve are all the body materials of the valve, the material code of the valve seat sealing surface is represented by "W"

Valve body material code

Valve body material	code name	Valve body material	code name
carbon steel	C	ductile cast iron	Q
Cr13 series stainless steel	H	0Cr17Ni12Mo2 series stainless steel	R
1Cr5Mo chromium molybdenum steel	I	00Cr17Ni14Mo2 series stainless steel	RL
15CrMo chromium molybdenum steel	H	plastic	S
malleable cast iron	K	copper and copper alloys	T
aluminum alloy	L	Titanium and titanium alloys	Ti
0Cr18Ni9 series stainless steel	P	Chromium molybdenum vanadium steel	V
00Cr19Ni10 series stainless steel	PL	gray cast iron	Z

Example of Model and Name Compilation Method

1、 Electric, flanged connection, rising stem wedge double gate valve, valve seat sealing surface material directly processed from valve body, nominal pressure PN1, valve body material is gray cast iron gate valve	Z942W-1 electric wedge double gate valve
2、 Manual, external thread connection, floating straight through type ball valve, valve seat sealing surface material is fluoroplastic, nominal pressure PN40, valve body material is 1Cr18Ni9Ti	Q21F-40P external thread ball valve
3、 Pneumatic normally open, flange connection, ridge structure with rubber lining, nominal pressure PN6, diaphragm valve with gray cast iron body material	G6K41J-6 Pneumatic Normally Open Rubber lined Diaphragm Valve
4、 Butterfly valve with hydraulic, flange connection, vertical plate type, valve seat sealing surface material made of cast copper, valve disc sealing surface material made of rubber, nominal pressure PN2.5, and valve body material made of gray cast iron	D741X-2.5 hydraulic butterfly valve
5、 Electric driven globe valve with welded connection, straight through type, valve seat sealing surface material made of hard alloy, working pressure of 17.0MPa at a working temperature of 540 ℃, and valve body material made of chromium molybdenum vanadium steel	J961Y-P54170V electric welding globe valve

Valve material performance (mainly based on JB/T 5300-1991 standard)

Valve body material	Applicable nominal pressure/MPa	Applicable temperature/℃	Applicable Medium
gray cast iron	≤10	－10～200	Water, steam, air, gas, oil and other media
malleable cast iron	≤25	－30～300	Water, steam, air, oil and other media
ductile cast iron	≤40	－30～350	Water, steam, air, oil and other media
copper alloy	≤25	－40～250	Media such as water, seawater, oxygen, air, and oil
carbon steel	≤320	－30～450	Media such as water, steam, air, hydrogen, ammonia, nitrogen, and petroleum products
High temperature steel	≤16	≤550	Steam and petroleum products
low-temperature steel	≤64	≥－196	Media such as ethylene, propylene, liquid natural gas, and liquid nitrogen
Stainless acid resistant steel	≤64	≤200	Nitric acid, acetic acid and other media

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