The Yoshitake AF-1 is an open type safety relief valve designed specifically for steam applications. It features a durable ductile cast iron (FCD450) valve case and high-quality stainless steel valve and valve seat components, making it suitable for working pressures up to 1.6 MPa and maximum temperatures of 220°C.

Features

• Larger discharge capacity than lift type.
• Due to lift lever mechanism a discharge inspection can be manually performed at more than 75% of the opening pressure.

Specifications

Structure	Open type with a lever
Application	Steam
Working pressure	0.18-1.6 MPa
Maximum temperature	220°C
Material (Valve case)	Ductile cast iron (FCD450)
Material (Valve, Valve seat)	Stainless steel
Connection	Inlet: JIS R screwed Outlet: JIS Rp screwed

INFO

• Rp is a parallel screw applicable to taper pipe thread.

Dimensions and Weights

Nominal size	Inlet diameter x Throat diameter x Outlet diameter (di x dt x do)	Flow area (mm²)	Lift (mm)	L (mm)	H1 (mm)	H (mm)	Weight (kg)
20A	R1 x 15 x Rp1	176.6	3.3	19	47	258	3.0
25A	R 1-1/4 x 19 x Rp 1-1/4	283.3	4.4	23	50	302	4.2
32A	R 1-1/2 x 26 x Rp 1-1/2	530.6	6.0	31	62	358	7.2
40A	R2 x 30 x Rp2	706.5	6.8	37	70	403	10.5
50A	R 2-1/2 x 38 x Rp 2-1/2	1133.5	8.7	46	89	466	18.5

INFO

• The nominal size and the connection size are different.

Certified Capacity Table for AF-1

For steam (saturation temperature) 〈Pressure vessel structure standard〉(kg/h)

Nominal size \ Pressure MPa	0.2	0.3	0.4	0.5	0.6	0.7	0.8	0.9	1.0	1.1	1.2	1.3	1.4	1.5	1.6
20A	231	310	390	468	545	621	697	773	849	925	1001	1076	1152	1227	1303
25A	370	498	627	751	875	997	1118	1240	1362	1484	1606	1726	1849	1968	2090
32A	694	932	1174	1407	1638	1868	2095	2323	2552	2780	3008	-	-	-	-

〈Boiler structure standard〉(kg/h)

Nominal size \ Pressure MPa	0.2	0.3	0.4	0.5	0.6	0.7	0.8	0.9	1.0	1.1	1.2	1.3	1.4	1.5	1.6
20A	227	299	372	443	515	587	659	729	800	872	942	1013	1084	1156	1227
25A	365	480	598	711	827	942	1057	1170	1284	1398	1512	1625	1740	1854	1968
32A	683	900	1120	1333	1550	1764	1980	2191	2406	2620	2833	-	-	-	-

TIP

Please refer to the calculation procedure of nominal size selection for additional values and sizes.