Yoshitake AL-24 and AL-24F are lift type safety relief valves designed with a diaphragm structure that eliminates sliding parts, ensuring highly reliable and non-leakage operation. The valve case is made of bronze, paired with a stainless steel valve seat, which provides excellent rust resistance. These valves offer a wide set pressure range from 0.1 to 0.7 MPa adjustable via a single spring, using a handle-type adjusting screw and a butterfly lock nut for ease of use. They provide smooth opening and closing even under continuous operation, maintaining stable flow relief from small to large capacities. They can be installed in any direction, horizontally or vertically.

Specifications

Model	AL-24	AL-24F
Application	Cold and hot water	Cold and hot water, Oil, Other non-dangerous fluids
Working pressure	0.1–0.7 MPa (*1)	0.1–0.7 MPa (*1)
Maximum temperature	60°C	120°C
Valve case	Bronze (*2)	Bronze (*2)
Valve	NBR	FKM
Valve seat	Stainless steel	Stainless steel
Diaphragm	EPDM	FKM
Connection	JIS Rc screwed	JIS Rc screwed

Notes

*1: Available with working pressure between 0.05 MPa and 0.1 MPa. *2: Available with NPb-treated.

Dimensions and Weights

Nominal size	d	L	L1	H	H1	D	Weight (kg)
15A	Rc 1/2	180.5	20.5	91	46	15	1.4
20A	Rc 3/4	181.5	18.5	92	47	15	1.4
25A	Rc 1	187.5	17.5	97	52	18.2	1.6

Certified Capacity

Set pressure range 0.1 to 0.7 MPa (accumulation 25%)(Unit: m³/h)

Nominal size	0.10	0.15	0.20	0.25	0.30	0.35	0.40	0.45	0.50	0.55	0.60	0.65	0.70
15A	0.31	0.38	0.44	0.49	0.54	0.58	0.63	0.66	0.70	0.73	0.77	0.80	0.83
20A	0.31	0.38	0.44	0.49	0.54	0.58	0.63	0.66	0.70	0.73	0.77	0.80	0.83
25A	0.46	0.56	0.65	0.73	0.80	0.86	0.92	0.98	1.03	1.08	1.13	1.18	1.22

Set pressure range 0.05 to 0.1 MPa (accumulation 25%)(Unit: m³/h)

Nominal size	0.05	0.06	0.07	0.08	0.09	0.10
15A	1.27	1.39	1.50	1.61	1.70	1.80
20A	1.27	1.39	1.50	1.61	1.70	1.80
25A	1.87	2.05	2.21	2.37	2.51	2.65

Calculation Formula

V = (A × K × 12.4) / √(G / P)

• V: Discharge capacity (m³/h)
• D: Seat diameter (mm)
• e: Lift (mm)
  • 0.1–0.7 MPa: e = D/40
  • 0.05–0.1 MPa: e = D/7
• A: Effective area (m²) (A = π × D × e)
• K: 0.7 (Flow rate coefficient)
• G: Specific gravity
• P: Opening pressure (MPa)

INFO

Viscosity is calculated from the formula for viscosity correction.

Structure and Parts

No.	Part Name	Material
15	Wing Nut	Steel
14	Adjusting Screw	Steel
13	Bolt	Steel
12	Spring Cover	Cast Iron (FC200)
11	Spring Plate	Carbon Steel (SPC)
10	Spring	Piano Wire (SWP)
9	Nut	Brass (C3604)
8	Spring Washer	Steel
7	Diaphragm Shell	Carbon Steel (SPC)