Yoshitake AL-32 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. The series features all stainless steel trim parts offering high corrosion resistance, and a closed structure that prevents fluid leakage. Closed lever types (AL-32ML, AL-32TML) can be manually inspected for blowout.

Features

• All stainless steel (SCS14A and SUS 316 for trim parts) offering high corrosion resistance.
• Closed structure prevents fluid leakage.

Specifications

Model	AL-32	AL-32T	AL-32ML	AL-32TML
Structure	Closed type	Closed type	Closed type with a lever	Closed type with a lever
Application	Steam, Air, Cold and hot water, Oil, Other non-dangerous fluids	Air, cold and hot water, Oil, Other non-dangerous fluids	Steam, Air, Cold and hot water, Oil, Other non-dangerous fluids	Air, cold and hot water, Oil, Other non-dangerous fluids
Working pressure	0.05-1.0 MPa	0.05-1.0 MPa	0.05-1.0 MPa	0.05-1.0 MPa
Working temperature	5-220°C*	5-120°C	5-220°C*	5-120°C
Connection	JIS 10K loose flanged	JIS 10K loose flanged	JIS 10K loose flanged	JIS 10K loose flanged
Nominal size	15-50A	15-50A	15-50A	15-50A
Material (Spring case)	Cast stainless steel	Cast stainless steel	Cast stainless steel	Cast stainless steel
Material (Valve, valve seat)	Stainless steel	Stainless steel	Stainless steel	Stainless steel
Material (Spring)	Stainless steel	Stainless steel	Stainless steel	Stainless steel
Material (O ring)	-	Composition rubber	-	Composition rubber

*The maximum temperature is 150°C when the fluid is liquid. AL-32T is recommended for hot and cold water applications.

WARNING

1. Do not apply the AL-32 and the AL-32ML to devices which do not allow any valve seat leakage. The AL-32 and the AL-32ML have allowable valve seat leakage and do not close completely.
2. Do not use the product for equipment or devices which vibrate excessively.

Dimensions and Weight

Nominal size	Flow area πDe (mm²)	D (mm)	L (mm)	H1 (mm)	H (mm) AL-32 / AL-32T	H (mm) AL-32ML / AL-32TML	Weight (kg) AL-32 / AL-32T	Weight (kg) AL-32ML / AL-32TML
15A	20.1	16	63	97	185	215	2.4	2.5
20A	34.6	21	87	101	187	217	2.8	2.9
25A	53.0	26	92	119	215	245	4.4	4.5
32A	93.3	33	99	135	255	284	5.2	5.3
40A	135.2	41	109	140	281	321	6.5	6.7
50A	208.2	51	114	162	332	372	11.3	11.5

*The outlet flange is 1 size larger than the nominal size.

Structure

No.	Part name	No.	Part name
1	Spring case	11	Cap
2	Valve seat	12	Gasket
3	Valve	13	Gasket
4	O-ring	14	Name plate
5	Spindle	15	Lever
6	Spring	16	Spring pin
7	Bottom spring plate	17	O ring
8	Top spring plate	18	Connecting rod
9	Adjusting screw	19	Spring pin
10	Lock nut	20	Pressure groove

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.

Rated Relief Capacity

For steam (at saturated temperature) : AL-32

Capacity (Pressure vessel structure standard) [kg/h]

Nominal size	0.05 MPa	0.1 MPa	0.2 MPa	0.3 MPa	0.4 MPa	0.5 MPa	0.6 MPa	0.7 MPa	0.8 MPa	0.9 MPa	1.0 MPa
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) : AL-32, AL-32T, AL-32ML, AL-32TML

Capacity (Pressure vessel structure standard) [kg/h]

Nominal size	0.05 MPa	0.1 MPa	0.2 MPa	0.3 MPa	0.4 MPa	0.5 MPa	0.6 MPa	0.7 MPa	0.8 MPa	0.9 MPa	1.0 MPa
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 (at 20°C, accumulation: 25%)

Capacity (Yoshitake standard) [m³/h]

Nominal size	0.05 MPa	0.1 MPa	0.2 MPa	0.3 MPa	0.4 MPa	0.5 MPa	0.6 MPa	0.7 MPa	0.8 MPa	0.9 MPa	1.0 MPa
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

INFO

[Example] When the set pressure is 1.0 MPa, and the valve size is 50A: The capacity is 22.4 m³/h, when the inlet pressure reaches 1.25 MPa (accumulation becomes 25%) after the fluid pressure reaches the set pressure of 1.0 MPa.

Installation

DANGER

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 because such closing device may hamper the blowout of the safety relief valve.
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.
4. When installing, do not loose the screw of the spring case and the valve seat.
5. Do not apply viscous fluid that may make fixation of the valve and valve seat.

WARNING

1. Before installing the product, remove foreign substances and scale from the piping.
2. When installing the product, match the direction of fluid flow with the inlet and outlet of the product respectively.
3. Install the product vertically with the cap facing upward.
4. Securely support and fasten the pipes.
5. Lead exhaust pipe to outside of buildings if there is a risk that fluid blowout causes alarm activation or contamination of the peripheral equipment.
6. Connect the product to the pipes securely.
7. If there is a risk that condensate or rain water accumulates in exhaust pipe, attach drain pipe with the product and/or the exhaust pipe in a position where they can be drained.
8. Inner diameters of pipe mount and of exhaust pipe shall be more than those of each inlet and outlet of the product.
9. Secure enough space required for maintenance or inspections.

Piping example

Maintenance

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
• Leakage from joints between the product and piping.

Monthly inspection

1. Check that there is no loose piping at inlet and outlet side of the product. Check that the cap is fastened securely.
2. Check the operation of the product by raising fluid pressure to the set pressure.

The differential Pressure in which the blow-off inspection by lever operation is possible:

Size	Differential pressure between set and inlet pressure
15-25A	1.0 MPa or less
32-40A	0.6 MPa or less
50A	0.4 MPa or less