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ＡＦ−７・７Ｍ
・７Ｍ・７Ｍ
・７Ｍ
ＦＵＬＬ
ＦＵＬＬＦＵＬＬ
ＦＵＬＬ ＢＯＲＥ
ＢＯＲＥＢＯＲＥ
ＢＯＲＥ ＳＡＦＥＴＹ
ＳＡＦＥＴＹＳＡＦＥＴＹ
ＳＡＦＥＴＹ ＶＡＬＶＥ
ＶＡＬＶＥＶＡＬＶＥ
ＶＡＬＶＥ
Instruction Manual
Thank you very much for purchasing our safety valves.
Please read this instruction manual thoroughly before using the safety valve, so that
you may do so correctly and safely. Please carefully store this manual in a handy place.
－－－－－－The following safety symbols are used in this manual.－－－－－
Warnings
Cautions
Contents
Overview･･･････････････････････････････････････････････1
1. Features･････････････････････････････････････････････1
2. Specifications････････････････････････････････････････1
3. Dimensions and weights･･････････････････････････2
4. Structure････････････････････････････････････････････3
5.Operation･････････････････････････････････････4
6.Size selection table .
6.1 For Steam (Pressure vessel structure specifications
・ Boiler structure specifications)･････4
6.2 For Air (Pressure vessel structure specifications )･･････4
7. Installation
7.1 Example of piping･････････････････････････････････5
7.2 Warnings and cautions of product installation････････5～6
8. Maintenance
8.1 Daily inspection･･････････････････････････････････6
8.2 Operational inspection････････････････････････････････7
8.3 Periodic inspection･･･････････････････････････････････ 7
8.4 Troubleshooting ･･････････････････････････････････････7
After sales service
This symbol indicates a potentially hazardous situation that, if not avoided,
could result in death or serious injury.
This symbol indicates a hazardous situation that, if not avoided, may result in
minor or moderate injury. (“Caution” may also be used to indicate other unsafe
p
ractices or risks of property damage.
)
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Overview
Suited for installation on steam boilers, various pressure vessels, instrumentation apparatus, and the
secondary side of pressure reducing valves. Yoshitake’s Safety Relief Valves prevent accidents due to
the abnormal rise in piping pressure.
1. Features
(1) The product is designed according to JIS B 8210 for spring loaded safety relief valves for
steam boilers and gas pressure vessels.
(2) The sealed structure of model AF-7M prevents any external leakage of fluid during operation.
2. Specifications
Model AF-7 AF-7M
Type
Open lever type*
1
Enclosed type*
2
Fluids
Steam, air, and other
non-corrosive gases
Air and other non-corrosive gases
Pressure range 0.1 ~ 1.0 MPa
Temperature range
5 ~ 350 ℃ 5 ~ 300℃
Super imposed back pressure 0 MPa
Connections
Inlet: JIS 10K RF flange or JIS 20K RF flange (JIS B 2238)
Outlet: JIS 10K FF flange (JIS B 2238)
Size (mm) 25, 40, 50, 65, 80, 100
Body Carbon steel casting
Material
Valve & valve seat Stainless steel
*1 A safety valve which is so constructed that a part of the fluid blown off from the valve seat
opening is also discharged outside from other part than the valve outlet.
*2
A safety valve which is so constructed that the fluid blown off from the valve seat opening
is not allowed to discharge outside from other part than the valve outlet.
Warnings
(1) Do not use this product on equipment and apparatus that do not allow any valve seat leakage.
＊This product has valve seat leakage within tolerance, and cannot be sealed completely
(Zero valve seat leakage cannot be obtained).
This product cannot be used for apparatus and facilities with considerable vibration.
＊Vibration may cause the product to make errors.
Cautions
Please confirm that the indications on the product name plate coincide with the specifications of
the ordered product model before usage.
＊ In case they do not coincide, do not use the product and contact us.
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3. Dimensions and Weights
Figure １ Dimensions （Model AF-7）
Connection
flange
＊H
2
(mm)
Size
(mm)
Inlet ×
Outlet
dt
(mm)
Blowout
area (mm
2
)
Rated lift
(mm)
L
(mm)
H
1
(mm)
AF-7 AF-7M
Weight
(kg)
25
25×32
16 200.9 4.0 100 85 226 231 10
40
40×50
25 490.6 6.3 120 110 273 270 20
50
50×65
32 803.8 8.0 135 120 325 321 25
65
65×80
40 1256.0 10.0 160 125 366 361 40
80
80×100
50 1962.5 12.5 170 135 375 370 52
100
100×125
65 3316.6 16.3 205 160 612 580 75
＊ All values for types AF-7 and AF-7M are identical except dimension of H
2
.
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4. Structure
Figure 2 Structure
No. Name of parts No. Name of parts
1 Body 14 Nut
2 Valve seat 15 Spring
3 Drain plug (R3/8) 16 Spindle
4 Seat ring 17 Spring chamber
7 Valve 19 Lever (on Model AF-7)
10 Valve holder 26 Name plate
11 Gu i de 29 S eal
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5．Operation
Discharge
When the pressure at the inlet side of the safety valve rises and approaches the set pressure, the
fluid pressure which pushes the valve ⑦ approaches the pressure of the spring ⑮ which is
holding down the valve ⑦. Pre-leaking which is as low as 3% of the discharge pressure occurs at
this point. (The pressure at this point is called the commence to discharge pressure. In case of
safety valve for gases, the set pressure is generally the commence to discharge pressure.)
The fluid which has started to pre-leak gradually accumulates in the valve holder ⑩, and when it
reaches the prescribed discharge pressure, the valve pops. (The pressure at this point is called the
popping pressure. In case of safety valves for steam, the set pressure is generally the popping
pressure.)
Closing
When the valve ⑦ pops, and the fluid is discharged into the air, the pressure on the safety valve
inlet decreases, lowering the pressure of the fluid to raise the valve. Thus, the resilience of the
spring ⑮ becomes stronger, and the valve closes. When the safety valve is discharging, the
pressure from the fluid coming in from the back of the valve holder ⑩ (back pressure) adds to the
pressure for the valve to close.
6. Size selection tables
6.1 For steam (Saturation temperature)
[Pressure vessel structure specifications・Boiler structure specifications ] (kg/h)
Set pressure (MPa)
size
(mm)
Bore of
throat
(mm)
Blowout
area
(mm
2
)
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
25 16 200.9
180 250 335 421 504 586 668 748 829 911
40 25 490.6
440 612 818 1028 1230 1432 1631 1828 2026 2225
50 32 803.8
721 1003 1341 1685 2016 2347 2673 2996 3320 3645
65 40 1256.0
1127 1567 2095 2633 3151 3667 4177 4682 5188 5697
80 50 1962.5
1761 2446 3274 4115 4923 5730 6526 7315 8106 8901
100 65 3316.6
2976 4139 5533 6954 8320 9684 11029 12363 13700 15043
6.2 For air (20℃) [Pressure vessel structure specifications] (kg/h)
Set pressure (MPa)
size
(mm)
Bore of
throat
(mm)
Blowout
area
(mm
2
)
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
25
16 200.9
278 424 570 716 862 1008 1154 1300 1446 1592
40
25 490.6
680 1036 1393 1749 2106 2462 2819 3175 3532 3888
50
32 803.8
1114 1698 2282 2866 3451 4035 4619 5203 5787 6371
65
40 1256.0
1742 2654 3567 4479 5392 6305 7217 8130 9042 9955
80
50 1962.5
2722 4148 5573 6999 8425 9851 11277 12703 14129 15555
100
65 3316.6
4600 7010 9419 11829 14239 16649 19058 21468 23878 26288
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7. Installation
7.1 Example of piping
Figure 3 Figure of piping example (for steam)
7.2 Warnings and cautions for product installation
Warnings
(1) This product is very heavy. Use a suspension or other device to support it securely at
installation.
＊The falling of the product may result in injuries.
(2) Attach an exhaust pipe onto the outlet so that the fluid is led to a safe place at discharge.
＊Be aware of scalding and other injuries at discharge.
Cautions
(1) Cleanse the inside of the pipe thoroughly and remove any dust or scales before installing the
product.
＊Remaining dust from insufficient cleansing may obstruct proper operation of the product.
(2) Remove the caps on the inlet and outlet of the product before installation.
(3) Match the fluid flow direction with the inlet and outlet of the product to ensure proper
installation.
＊The product will not function if installed improperly.
(4) Please make sure that the product is installed in the proper direction.
＊The product will not function if installed in an improper direction.
(5) Securely support and fasten the piping.
＊Excess stress on the piping will cause deformation, obstructing proper opening and closing of
the valve.
(6) Do not remove the seal from the product.
(7) Upon installation, please choose a place with sufficient space for removal of the product.
＊Insufficient space will obstruct exchange and other necessary work on the product.
(8) If the product is installed in a place where the fluid discharge may trigger the alarm or soil
other equipment, extend the exhaust pipe to the outside of the building.
＊Lack of consideration for the location of the exhaust pipe end can result in soiling of other
equipment.
(9) Please ensure that the piping connections are secure.
＊Improper connections can result in leaking from the joints with vibrations, and scalding from
the fluid.
(10) Since the fluid leaks from model AF-7 upon operation, please take measures to prevent
soiling of other equipment.
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●Cleansing the inside of the piping
(1) Please
cleanse the inside of the pipe thoroughly and remove any dust or scales before
installing the product. Please note that all repairs for disorders due to foreign matters shall
be charged.
●Installation pipe mount for the safety valve
(1) The pipe mount for the safety valve should have sufficient strength and rigidity
against compression, shear and bending stress that is caused in the reaction against
the exhaust flowing up through the exhaust pipe attached to the safety valve.
(2) Install the safety valve vertically as close as possible to the can body and header. By
doing so, the pressure loss of the mount can be suppressed, preventing decrease in
the discharge volume and unstable functioning of the safety valve.
●Installation of an exhaust pipe onto the safety valve
(1) Install an exhaust pipe and expansion joint so that the stress caused by the thermal
expansion of the equipment or the fluctuation of the exhaust pipe due to the heat of
the safety valve does not affect the safety valve.
●Installation of the flange on the safety valve inlet
(1) As the valve seat is screwed on to the flange inlet, there is a difference in level on the
flange surface of this product. Upon installation, apply a flange gasket that suits the
nominal size and make sure that the gasket seals the valve seat completely (See
Figure 4).
Figure 4 Installation of flange on the inlet
8．Maintenance
Cautions
(1) Be sure to wear gloves when touching the product or piping.
＊Be aware of scalding or injuries.
(2) Wear earplugs when checking the operation of the product, and do not stand in front of the
exhaust pipe .Do not look into the pipe or put your hand out to the pipe.
＊The product makes a loud blowing noise during operation. Be aware of spluttering fluid from
the product.
(3) In case of raising the fluid pressure, check beforehand that no problems will occur regarding
the equipment installed onto the piping.
＊Be aware of damage to the equipment.
(4) Do not disassemble the product.
8.1 Daily inspection
Please check to see if there is any fluid leaking from the product or piping on the outlet side of
the product.
＊Please contact us if you notice anything abnormal.
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8.2 Operational inspection (every half year)
(1) Check to see that installation bolts and nuts at the product inlet and outlet, as well as nuts ⑭
installed on the product are all fastened securely.
(2) In case of model AF-7 (lever type), raise the fluid pressure to 75% of the set pressure or
higher, raise the lever, and check to see that the fluid blows out. In case of type AF-7M
(closed type), raise the fluid pressure to the set pressure, and confirm that the product
operates.
＊Please contact us if you notice anything abnormal.
8.3 Periodic inspection
Implement various voluntary inspections according to the laws. If you are a general user, please
have the facility or works agent implement the inspection.
8.4 Troubleshooting
Problem Cause Measures and treatment
A scale is stuck between
the valve ⑦ and valve
seat ②.
Follow the procedures in 8.2(2) and operate
the safety valve. Contact us If the leakage
still fails to stop.
The piping on which the
product is installed vibrates.
This product cannot be used on devices and
equipment that vibrate considerably.
Leakage at the outlet
side.
There is back pressure on
the piping at the outlet
side.
Review and change the piping layout.
Specifications of the product and conditions for usage do not coincide.
Check the set pressure printed on the
nameplate. Exchange the product if the
conditions for usage do not coincide.
The pressure gauge does
not work properly
Calibrate or exchange the pressure gauge.
Operates at pressures
lower than the set pressure.
Changes occurred in the
set pressure of the product.
The readjustment of set pressure is needed.
Please contact us.
Specifications of the safety
valve and conditions for
usage do not coincide.
Check the set pressure printed on the
nameplate. Exchange the product if the
usage conditions do not coincide.
The pressure gauge does
not work properly
Calibrate or exchange the pressure gauge.
Changes occurred in the
set pressure of the safety
valve.
The readjustment of set pressure is needed.
Please contact us.
Does not operate even
though the pressure
reaches the set pressure.
The valve holder ⑩ and
the guide ⑪ got stuck to-
gether.
The product needs to be disassembled and
cleaned. Please contact us.
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