Yoshitake AL-32T safety relief valves are closed-type valves 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 AL-32T features an all-stainless steel construction with a soft seat (FKM O-ring), providing excellent air tightness. It is highly suitable for applications where valve seat leakage is not tolerated, such as with air, water, oil, and other non-dangerous fluids.

Features

• High Corrosion Resistance: All stainless steel construction (trim parts: SCS14A and SUS316).
• Non-Leakage: Excellent air tightness ensured by the valve seat incorporating a soft seat (O-ring). Most suitable for applications where valve seat leakage is not tolerated.
• Closed Structure: Prevents fluid leakage to the outside environment.

Specifications

Model	AL-32T	AL-32T-N
Structure	Closed type	Closed type
Application	Air, water, oil, other non-dangerous fluid	Cold and hot water
Working pressure	0.05 - 1.0 MPa	0.05 - 1.0 MPa
Working temperature	5 - 120°C	5 - 100°C
Connection	JIS 10K loose flange	JIS 10K loose flange

INFO

Please contact us when using for oil. The AL-32T-N model features JWWA approval.

Dimensions and Weights

Nominal size	D (mm)	L (mm)	H1 (mm)	H (mm)	Flow area (mm²)	Weight (kg)
15A	16	63	97	185	20.1	2.4
20A	21	87	101	187	34.6	2.8
25A	26	92	119	215	53.0	4.4
32A	33	99	135	255	93.3	5.2
40A	41	109	140	281	135.2	6.5
50A	51	114	162	332	208.2	11.3

Note: The outlet flange is 1 size larger than the nominal size.

Structure and Materials

No.	Part Name	Material
1	Spring Case	Cast Stainless Steel (SCS14A or SCS13)
2	Valve Seat	Stainless Steel (SUS316)
3	Valve	Cast Stainless Steel (SCS14A)
4	Valve Cover	Stainless Steel (SUS304)
5	O Ring	FKM
6	C Ring	Stainless Steel (SUS)
7	Spindle	Stainless Steel (SUS)
8	Spring	Stainless Steel (SUS304)
9	Bottom Spring Plate	Stainless Steel (SUS)
10	Top Spring Plate	Stainless Steel (SUS)
11	Adjusting Screw	Stainless Steel (SUS)
12	Lock Nut	Stainless Steel (SUS)
13	Cap	Stainless Steel (SUS)
14	Gasket	PTFE
15	Gasket	PTFE

Nominal Size Selection Table

For Air (at 20°C)

Capacity (kg/h) based on Pressure vessel structure standard:

Nominal size	Blowout area [mm²]	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	20.1	25	33	48	65	81	98	114	131	147	164	181
20A	34.6	44	57	83	111	140	169	197	226	254	283	311
25A	53.0	67	87	127	171	215	258	302	346	390	433	477
32A	93.3	113	147	214	288	362	435	509	582	656	730	803
40A	135.2	169	221	321	431	542	652	762	872	982	1093	1203
50A	208.2	262	341	496	666	836	1006	1176	1346	1516	1687	1857

For Water (at 20°C, accumulation: 25%)

Capacity (m³/h) based on Yoshitake standard:

Nominal size	Blowout area [mm²]	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	20.1	0.4	0.5	0.9	1.1	1.3	1.5	1.6	1.8	1.9	2.0	2.1
20A	34.6	0.6	0.9	1.6	2.0	2.3	2.6	2.8	3.1	3.3	3.5	3.7
25A	53.0	1.0	1.5	2.5	3.1	3.6	4.0	4.4	4.7	5.1	5.4	5.7
32A	93.3	1.8	2.6	4.5	5.5	6.3	7.1	7.8	8.4	9.0	9.5	10.0
40A	135.2	2.7	3.8	6.5	7.9	9.2	10.3	11.3	12.2	13.0	13.8	14.6
50A	208.2	4.1	5.9	10.0	12.3	14.2	15.9	17.4	18.8	20.1	21.3	22.4

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.

Installation

DANGER

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 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

Caution

• 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. Inner diameters of pipe mount and of exhaust pipe shall be more than those of each inlet and outlet of the product.
• Avoid rapid pressure change. Impact by a rapid pressure change, such as water hammer, may damage the product/parts.

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 (check it visually and aurally).
• 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. In addition, check that the cap is fastened securely.
2. Check the operation of the product by raising fluid pressure to the set pressure.

Troubleshooting

Trouble	Cause	Remedy
Leakage detected visually/aurally at the outlet	1. Foreign substance or scale stuck on contact surface. 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. 5. Pressure momentarily exceeds set pressure because of fluid pulsation. 6. Fluid flows into the outlet piping.	1. Operate the product to eliminate foreign substance. 2. Disassemble and replace parts. 3. Do not use on excessively vibrating equipment. 4. Increase the pressure difference. 5. Raise set pressure or lower normal working pressure. 6. Change piping layout.
Blows at a pressure lower than the set pressure	1. Product specifications are not consistent with use condition. 2. Pressure gauge is out of order. 3. Product does not keep 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 use condition. 2. Pressure gauge is out of order. 3. Sliding parts do not move smoothly. 4. Back pressure at the piping of the product outlet. 5. Product does not keep accuracy of its set pressure.	1. Check set pressure indication. Replace if unsuitable. 2. Calibrate or replace pressure gauge. 3. Disassemble and clean. 4. Remove back pressure. Change piping layout. 5. Readjust set 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. 4. Installed at outlet side of malfunctioning pressure reducing valve.	1. Operate the product to eliminate foreign substance. 2. Disassemble and clean. 3. Increase difference between set pressure and normal working pressure. 4. Repair the pressure reducing valve.