Yoshitake AL-140H safety relief valve is designed for various pressure vessels, instrumentation devices, and at the outlet of pressure reducing valves to prevent accidents caused by abnormal pressure rise. It is a closed-type, full stainless steel safety relief valve suitable for steam, air, cold and hot water, oil, and other non-dangerous fluids.

Features

• Safety valve of all stainless steel made. SCS14A (equivalent to SUS316) with outstanding corrosion resistance is used for the trim parts.
• Popping structure ensures reliable discharge.
• Simple structure and easy to handle.
• Closed structure prevents fluid leakage.

Usage Restrictions

• 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 (valve seat leakage cannot be zero).
• Do not use the product for equipment or device which vibrates excessively, as it may result in malfunction.
• Do not adjust or change the set pressure, as it may result in damage to the equipment.

Dimensions and Weights

• Screwed connection size of the outlet side is 1 size larger than the nominal size.

Nominal Size	Dimension di × D × do	L (mm)	H1 (mm)	H (mm)	Flow Area πDe (mm²)	Weight (kg)
15A	Rc 1/2 × 16 × Rc 3/4	36	42	126.5	20.1	0.9
20A	Rc 3/4 × 21 × Rc 1	38	46	130.5	34.6	1.0
25A	Rc 1 × 26 × Rc 1-1/4	46	55	150.5	53.0	1.5
32A	Rc 1-1/4 × 33 × Rc 1-1/2	54	61.5	195	93.3	2.5
40A	Rc 1-1/2 × 41 × Rc 2	63	67	227.5	135.2	4.6
50A	Rc 2 × 51 × Rc 2-1/2	77	80	303.5	208.2	8.8

Structure

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

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

Steam (Saturation Temperature)

Pressure vessel structure standard. Capacity in kg/h.

Nominal Size	1.0 MPa	1.1 MPa	1.2 MPa	1.3 MPa	1.4 MPa	1.5 MPa	1.6 MPa	1.7 MPa	1.8 MPa	1.9 MPa	2.0 MPa
15A	109	119	129	139	149	158	168	178	188	198	207
20A	189	206	222	239	256	273	290	306	324	340	357
25A	289	315	341	367	393	418	444	470	496	522	547
32A	487	531	574	617	661	704	747	791	835	878	921

Air (20°C)

Pressure vessel structure standard. Capacity in kg/h.

Nominal Size	1.0 MPa	1.1 MPa	1.2 MPa	1.3 MPa	1.4 MPa	1.5 MPa	1.6 MPa	1.7 MPa	1.8 MPa	1.9 MPa	2.0 MPa
15A	181	197	214	230	247	264	280	297	313	330	347
20A	311	340	368	397	426	454	483	511	540	568	597
25A	477	521	565	608	652	696	740	783	827	871	915
32A	803	877	950	1024	1098	1171	1245	1318	1392	1466	1539

Water (Accumulation: 25%)

Yoshitake standard. Capacity in m³/h.

Nominal Size	1.0 MPa	1.1 MPa	1.2 MPa	1.3 MPa	1.4 MPa	1.5 MPa	1.6 MPa	1.7 MPa	1.8 MPa	1.9 MPa	2.0 MPa
15A	2.1	2.2	2.3	2.4	2.5	2.6	2.7	2.8	2.9	2.9	3.0
20A	3.7	3.9	4.0	4.2	4.4	4.5	4.7	4.8	5.0	5.1	5.2
25A	5.7	6.0	6.2	6.5	6.7	7.0	7.2	7.4	7.6	7.8	8.0
32A	10.0	10.5	11.0	11.4	11.9	12.3	12.7	13.1	13.5	13.8	14.2

Installation

Pre-installation

Before installing the product, remove foreign substances and scale from the piping to prevent malfunction.

Important Warnings

• Do not install any closing device such as a stop valve at inlet or outlet sides of the product. This may hamper the blowout of the safety relief valve and result in damage to the pressure vessel.
• 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.
• Do not disassemble the product. When installing, tighten the hexagonal part of the valve seat with a spanner. Do not adjust its direction by rotating the outlet piping.