Boiler Safety Valve for Steam, Gas, Air, Water

• Certification: ISO, CE
• Temperature: High Temperature
• Connection: Flange or Thread
• Pressure: Non-Ajustable
• Closed: Closed
• Structure: Spring
• Model NO.: A21
• Material: Stainless Steel, Brass, Cast Iron
• Process Temperature: Less Than 350ºC
• Port Size: 1/4 to 12′′
• Operation: Automatic
• Ends: DIN Flange; G Thread; NPT, Bsp; R.F/S.W
• Pressure Rating: 1.6MPa to 32MPa; 150lb~2500lb
• Transport Package: Carton or Wooden Case
• Specification: measuring medium: gas, oil, water, steam
• Trademark: U-ideal
• Origin: Tianjin, China
• HS Code: 8481804090
• Production Capacity: 1000PCS/Month

Product Description

  Safety valve/Pressure relieving valve

1. Application

     A21H is applicable to equipment or piping for air, ammonia,oil gas and other medium with operating temperature less than 200 ºC. A21W is applicable to equipment or piping for corrosive gas or liquid and other medium with operating temperature less than 200 ºC. 1Fis applicable to equipment or piping for LPG,oil gas and other medium with operating temperature less than 200 ºC as over pressure protection. When Pressure exceeds the allowable value, the valve automatically open, and then the full amount is released; when the pressure reduced to the specified value, the valve automatically shut down to ensure the safe operation of equipment.

   2. Set pressure grouping

PN( nominal pressure)	Set Pressure grade
1.6	0.06-0.1   0.1-0.16 0.16-0.25  0.25-0.4  0.4-0.6  0.6-0.8  0.8-1.0 1.0-1.3  1.3-1.6
2.5	> 1.3-1.6    > 1.6-2.0   > 2.0-2.5
4.0	> 1.3- 1.6    > 1.6- 2.0   > 2.0- 2.5   > 2.5-3.2 > 3.2- 4.0
6.4	> 2.5- 3.2    > 3.2- 4.0   > 4.0- 5.0   > 5.0-6.4
10.0	> 4.0- 5.0   > 5.0- 6.4   > 6.4- 8.0   > 8.0-10
16.0	> 10-13    > 13-16
32.0	> 16-19     > 19-22    > 22-25   > 25-29 > 29-32

 
3. Inlet and outlet flange size
PN refer to Table 5; inlet and outlet DN refer to Table 6 ( MPa)
Table 5

PN( nominal pressure)	1.6	2.5	4.0	6.4	10.0	16.0	32.0
Inlet flange pressure grade	1.6	2.5	4.0	6.4	10.0	16.0	32.0
Outlet flange pressure grade	1.6	1.6	1.6	4.0	4.0	4.0/16.0	16.0

Table6

Safety valve's Open Type	Low lift	Full lift
Inlet DN		the same as DN
Outlet DN	the same as DN	Larger than DN by one degree or more

 4. Performance specification(as per GB12243-2005)

Medium	Shell-test pressure Ps(MPa)	Seal test pressure PM(MPa)	Displace pressure  △P(MPa)	Relieving pressure Pp (MPa)	Lift height H(mm)
steam	1.5PN	90% Pk or the minimum return pressure,	Pk≤0.4, it's ≤ 0.04 Pk >0.4, it's ≤ 0.1Pk	≤1.03Pk	full lift	≥1/4do
					low lift	≥1/20 do
Air or other gas		When Pk<0.3, it's Pk-0.03; When Pk≥0.3, it's 90%Pk	Pk≤0.2, it's ≤  0.03 Pk >0.2, it's ≤ 0.15Pk	≤1.1Pk	full lift		≥1/4do
					low lift		≥1/20do
Water or other liquid			Pk≤0.3, it's ≤  0.06 Pk >0.3, it's ≤ 0.2Pk	≤1.2Pk	full lift		≥1/4do
					low lift		≥1/20do

Note: Pk is set pressure, do is orifice diameter.
5. Main dimension( mm)

 

Type	(DN)	do	d	Do	G	D1	L	h1	h	M	≈H
16 A21- 25     40	15	10	13	20	1/2''	30	36	57	82	M27*1.5	66
	20	14	18	25	3/4''	35	41	60	90	M33*1.5	68
	25	17	23	31	1''	42	52	70	105	M39*1.5	105
A21- 64     100	15	10	15	25	1''	42	52	70	105	M39*1.5	105
	20	10	15	25	1''	42	52	70	105	M39*1.5	105
	25	12	15	25	1''	42	52	70	105	M39*1.5	105
A21- 160     320	15	8	10	20	M33*2	46	52	70	105	M30*2	105
	20	8	15	25	M33*2	46	52	70	105	M30*2	105
	25	8	18	28	M33*2	46	52	70	105	M30*2	105

 
6. Main parts material

Parts name	A21H-C/A21F KA21Y-C    material	A21W-P/A21F-P   KA21Y-P    material	A21Y-R    material
coupling	20	1Cr18Ni9Ti	1Cr18Ni12Mo2Ti
coupling nut	35	2Cr13	1Cr18Ni9Ti
seat	35	1Cr18Ni9Ti	1Cr18Ni12Mo2Ti
body	2Cr13	1Cr18Ni9Ti	1Cr18Ni12Mo2Ti
disc	2Cr13/2Cr13+PTFE	1Cr18Ni9Ti/1Cr18Ni9Ti+PTFE	1Cr18Ni12Mo2Ti
Spring seat	2Cr13	1Cr18Ni9Ti	1Cr18Ni12Mo2Ti
spring	50CrVA	50CrVAfluorine	50CrVA fluorine
Locknut	0235-A	2Cr13	1Cr18Ni9Ti
Spring guide pad	2Cr13	1Cr18Ni9Ti	1Cr18Ni12Mo2Ti
Adjusting nut	0235-A	2Cr13	1Cr18Ni12Mo2Ti
Seal surface material	Y type  surfacing Co-based hard alloy	W type surfacing D 507	F type PTFE