Yoshitake AL-150 is a versatile, closed-type safety relief valve compatible with fluids such as steam, air, water, and oil. It is mainly used in various pressure vessels, instrumentation devices, and at the outlet of pressure reducing valves to prevent accidents caused by abnormal pressure rise. The trim parts (valve and valve seat) and adjusting spring are made of high-quality stainless steel, ensuring outstanding corrosion resistance and reliable performance.

Features

• Versatile Application: Compatible with fluids such as steam, air, water, and oil.
• High Performance: Achieved the highest performance by segmentalizing the pressure range and finishing with ultra-precision techniques.
• Corrosion Resistant: The trim parts (valve and valve seat) are made of SCS14A (equivalent to SUS316), and the adjusting spring is made of stainless steel.
• Closed Structure: Prevents fluid leakage to the outside.

Specifications

Specification	Value
Structure	Closed type
Application	Steam, Air, Hot and cold water, Oil, Other non-dangerous fluids
Working pressure	0.05 - 1.0 MPa
Working temperature	5 - 220°C (Max 150°C when using for water, oil, or other liquids)
Connection	JIS Rc screwed
Material (Spring case)	Bronze / Cast bronze
Material (Valve, Valve seat)	Stainless steel (SCS14A)
Material (Adjusting spring)	Stainless steel

Note

AL-150T is recommended for hot and cold water applications.

WARNING

1. Do not apply the product to devices which do not allow any valve seat leakage. The product has allowable valve seat leakage and does not close completely.
2. Do not use the product for equipment or devices which vibrate excessively.
3. Do not adjust or change the set pressure. Failure to follow this notice may result in damage to the equipment.

Structure and Materials

No.	Part Name	Material
1	Spring case	Bronze (CAC406)
2	Valve seat	Cast Stainless Steel (SCS14A)
3	Valve	Cast Stainless Steel (SCS14A)
4	Spindle	Brass
5	Spring	Stainless Steel (SUS304)
6	Bottom spring plate	Brass
7	Top spring plate	Brass
8	Adjusting screw	Brass
9	Lock nut	Brass
10	Cap	Brass
11	Gasket	PTFE
12	Gasket	PTFE
13	Name plate	Stainless Steel (SUS304)

Dimensions and Weights

Nominal size	d	D (mm)	L (mm)	H1 (mm)	H (mm)	Flow area (mm²)	Weight (kg)
15A	Rc 1/2	16	34	40	128	20.1	0.7
20A	Rc 3/4	21	38	43	128.5	34.6	0.8
25A	Rc 1	26	43	51.5	144.5	53.0	1.1
32A	Rc 1-1/4	33	50	61.5	181.5	93.3	1.8
40A	Rc 1-1/2	41	60	60	205	135.2	2.8
50A	Rc 2	51	75	76	245.5	208.2	4.7

Operation

Blowout Operation

As the inlet pressure approaches the blowout pressure, the force of fluid pushing up the valve approaches the force of the spring pressing down the valve. The safety relief valve commences to blow when the inlet pressure reaches around 3% below the blowout pressure. The fluid accumulates gradually on the pressure groove and when the fluid pressure reaches the blowout pressure the valve pops.

Closing Operation

Since the inlet pressure of the safety relief valve decreases when the fluid is released into the atmosphere by the pop action of the valve, the force of fluid lift is lowered. At this point, the repelling force of the spring becomes larger than the force of fluid lift and thus the valve closes. In addition, while the safety relief valve discharges, pressure of fluid entering into the back of the valve (back pressure) adds to the closing force.

Certified Capacity Tables

For Steam (Saturation Temperature)

Capacity according to Pressure vessel structure standard (kg/h):

| Nominal size \ Pressure MPa | 0.05 | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | 1.0 | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | 15A | 15 | 20 | 29 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | 109 | | 20A | 27 | 35 | 51 | 69 | 87 | 104 | 121 | 138 | 155 | 172 | 189 | | 25A | 42 | 54 | 78 | 105 | 133 | 159 | 186 | 212 | 237 | 263 | 289 | | 32A | 70 | 91 | 132 | 178 | 224 | 268 | 313 | 356 | 400 | 443 | 487 | | 40A | 105 | 136 | 198 | 266 | 335 | 402 | 468 | 534 | 599 | 664 | 729 | | 50A | 163 | 211 | 306 | 411 | 518 | 621 | 723 | 824 | 924 | 1025 | 1126 |

For Air (at 20°C)

Capacity according to Pressure vessel structure standard (kg/h):

| Nominal size \ Pressure MPa | 0.05 | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | 1.0 | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | 15A | 25 | 33 | 48 | 65 | 81 | 98 | 114 | 131 | 147 | 164 | 181 | | 20A | 44 | 57 | 83 | 111 | 140 | 169 | 197 | 226 | 254 | 283 | 311 | | 25A | 67 | 87 | 127 | 171 | 215 | 258 | 302 | 346 | 390 | 433 | 477 | | 32A | 113 | 147 | 214 | 288 | 362 | 435 | 509 | 582 | 656 | 730 | 803 | | 40A | 169 | 221 | 321 | 431 | 542 | 652 | 762 | 872 | 982 | 1093 | 1203 | | 50A | 262 | 341 | 496 | 666 | 836 | 1006 | 1176 | 1346 | 1516 | 1687 | 1857 |

For Water (Accumulation: 25%)

Capacity according to Yoshitake standard (m³/h):

| Nominal size \ Pressure MPa | 0.05 | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | 1.0 | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | 15A | 0.4 | 0.5 | 0.9 | 1.1 | 1.3 | 1.5 | 1.6 | 1.8 | 1.9 | 2.0 | 2.1 | | 20A | 0.6 | 0.9 | 1.6 | 2.0 | 2.3 | 2.6 | 2.8 | 3.1 | 3.3 | 3.5 | 3.7 | | 25A | 1.0 | 1.5 | 2.5 | 3.1 | 3.6 | 4.0 | 4.4 | 4.7 | 5.1 | 5.4 | 5.7 | | 32A | 1.8 | 2.6 | 4.5 | 5.5 | 6.3 | 7.1 | 7.8 | 8.4 | 9.0 | 9.5 | 10.0 | | 40A | 2.7 | 3.8 | 6.5 | 7.9 | 9.2 | 10.3 | 11.3 | 12.2 | 13.0 | 13.8 | 14.6 | | 50A | 4.1 | 5.9 | 10.0 | 12.3 | 14.2 | 15.9 | 17.4 | 18.8 | 20.1 | 21.3 | 22.4 |

Installation

Warning

1. Do not install any closing device such as a stop valve at inlet or outlet sides of the product. Such closing device may hamper the blowout of the safety relief valve.
2. Install an exhaust pipe on the outlet side of the product, and lead it to a place where there is no risk of physical damage even if fluid blows out.
3. When installing, tighten the hexagonal part of the valve seat with a spanner. Do not adjust its direction by rotating the outlet piping.

Installation Cautions

• Before installing the product, remove foreign substances and scale from the piping.
• Install the product vertically with the cap facing upward.
• Securely support and fasten the pipes. If an excessive stress is applied to the piping, the product may be deformed and not open/close.
• Inner diameters of pipe mount and of exhaust pipe shall be more than those of each inlet and outlet of the product.

Maintenance and Troubleshooting

Daily Inspection

Check the following items while the system is in operation:

• Corrosion or crack on the product.
• Leakage from the product under normal working pressure (check visually and aurally).
• Leakage from joints between the product and piping.

Troubleshooting

Trouble	Cause	Remedy
Leakage detected visually/aurally at the outlet	1. Foreign substance or scale stuck on contact surface between the valve and valve seat. 2. Damage on contact surfaces. 3. Excessive vibration applied to the piping. 4. Pressure difference between set pressure and normal working pressure is too small.	1. Operate the product to eliminate the foreign substance. 2. Disassemble and replace parts. 3. Do not use on excessively vibrating equipment. 4. Increase the pressure difference.
Blows at a pressure lower than the set pressure	1. Product specifications are not consistent with the use condition. 2. Pressure gauge is out of order. 3. Product does not keep the accuracy of its set pressure.	1. Check set pressure indication. Replace if unsuitable. 2. Calibrate or replace pressure gauge. 3. Readjust set pressure.
Does not operate at the set pressure	1. Product specifications are not consistent with the use condition. 2. Pressure gauge is out of order. 3. Sliding parts do not move smoothly. 4. Back pressure at the outlet piping.	1. Replace with a proper model. 2. Calibrate or replace pressure gauge. 3. Disassemble and clean. 4. Remove back pressure.
Does not stop blowing	1. Foreign substance or scale stuck on contact surface. 2. Sliding parts do not move smoothly. 3. Normal working pressure exceeds closing pressure.	1. Start up the product to remove scale. 2. Disassemble and clean. 3. Increase difference between set pressure and normal working pressure.