Yoshitake AL-150T series safety relief valves are used mainly in various pressure vessels, instrumentation devices, and at the outlet of pressure reducing valves to prevent accidents caused by abnormal pressure rise. They feature a closed type structure and a soft seat (FKM O-ring) that ensures reliable airtightness, making them suitable for applications where valve seat leakage is not tolerated. The trim parts are made of corrosion-resistant stainless steel.

Features

1. Safety relief valve with excellent airtightness ensured by the valve seat incorporating soft seat. Most suitable for applications where valve seat leakage is not tolerated.
2. The trim parts (valve and valve seat) and adjusting spring are made of stainless steel. Used for the trim parts is SCS14A (equivalent to SUS316) with outstanding corrosion resistance.
3. Closed structure prevents fluid leakage.

Specifications

Model	AL-150T	AL-150T-N
Structure	Closed type	Closed type
Application	Air, Cold and hot water, Oil, Other non-dangerous fluids	Cold and hot water
Working pressure	0.05-1.0 MPa	0.05-1.0 MPa
Working temperature	5-120°C	5-100°C
Spring case	Bronze	Bronze (NPb-treated)
Valve, valve seat	Stainless steel (SCS14A)	Stainless steel (SCS14A)
Adjusting spring	Stainless steel	Stainless steel
O-ring	FKM	FKM
Connection	JIS Rc screwed	JIS Rc screwed

Dimensions and Weights

Nominal size	d	D (mm)	L (mm)	H1 (mm)	H (mm)	Flow area πDe (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

Certified Capacity

For steam (saturation temperature)

(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

For air (20°C)

(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

For water (accumulation: 25%)

(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

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 gets lower than the blowout pressure. Then, when the inlet pressure rises and 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.

Installation

Caution

1. Do not install any closing device such as a stop valve at inlet or outlet sides of the product. Failure to follow this notice may result in damage to the pressure vessel.
2. Install an exhaust pipe on 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. Do not disassemble the product. When installing, tighten the hexagonal part of the valve seat with a spanner.

Maintenance

Daily inspection Check the following items while the system is in operation:

• Leakage from the product under normal working pressure.
• Corrosion or crack on the product.
• Leakage from the joint between the product and piping, and between the spring case and the valve seat.

Regular inspection (once per 6 months)

• Check that there is no loose piping at inlet and outlet side of the product.
• Check the operation of the product by raising fluid pressure to the set pressure.