The Yoshitake AF-10EN is a full bore safety valve with an open-type lever structure, designed in accordance with ISO4126-1: 2013. It is engineered for use with steam, air, and other non-dangerous gases, providing a large discharge capacity and highly reliable operation. The valve features a ductile cast iron body and stainless steel valve and seat, ensuring durability under demanding conditions. A key operational advantage is the ability to manually perform discharge inspections using the lever when the inlet pressure reaches 80% or more of the set pressure.

Features

1. Full bore safety valve designed according to ISO4126-1: 2013.
2. Large discharge capacity and highly reliable operation.
3. Discharge inspection can be manually performed with the lever at 80% or more of the set pressure.

Specifications

Parameter	Description
Model	AF-10EN
Structure	Open type with lever
Application	Steam, Air, and Other non-dangerous gases *1
Nominal size	20A x 32A, 25A x 40A, 32A x 50A, 40A x 65A, 50A x 80A, 65A x 100A, 80A x 125A, 100A x 150A
Working pressure	0.1 to 1.6 MPa *2
Maximum temperature	250 °C *2
Material (Body / Spring chamber)	Ductile cast iron
Material (Valve / Valve seat)	Stainless steel
Connection	EN PN16 flanged (Outlet is two sizes larger than inlet)

*1 The valve cannot be used for liquid application. *2 The relationship between working pressure and temperature as per EN1092-2.

Spring Range

A	B	C	D	E
0.1 – 0.15 MPa	0.15 – 0.2 MPa	0.2 – 0.25 MPa	0.25 – 0.35 MPa	0.35 – 0.45 MPa

F	G	H	I
0.45 – 0.65 MPa	0.65 – 0.85 MPa	0.85 – 1.2 MPa	1.2 – 1.6 MPa

Pressure and Temperature Rating

According to EN1092-2 (PN16):

Material	up to 120 °C	150 °C	200 °C	250 °C
Ductile cast iron	1.6 MPa	1.55 MPa	1.47 MPa	1.39 MPa

Note: Intermediate values may be obtained by linear interpolation.

Dimensions and Structure

Parts List:

1. Body (Ductile Cast Iron)
2. Spring Chamber (Ductile Cast Iron)
3. Cap (Ductile Cast Iron)
4. Lever (Ductile Cast Iron or Cast Iron)
5. Valve (Stainless Steel)
6. Valve Seat (Stainless Steel)
7. Valve Cover (Stainless Steel)
8. Guide Plate (Ductile Cast Iron)
9. Spindle A (Stainless Steel)
10. Spindle B (Stainless Steel)
11. Spring (Alloy Steel or Spring Steel)
12. Adjusting Screw (Brass)

Nominal size	Inlet x Outlet	Throat dia. d0 (mm)	Flow area (mm²)	L (mm)	H1 (mm)	H (mm)	Weight (kg)
20A	20 x 32	18.5	268	85	85	360	10
25A	25 x 40	23	415	100	100	375	11
32A	32 x 50	29.5	683	105	110	450	15
40A	40 x 65	36.5	1046	115	125	470	17
50A	50 x 80	46	1661	120	130	510	24
65A	65 x 100	59.5	2780	140	160	680	38
80A	80 x 125	73	4185	160	180	785	53
100A	100 x 150	91	6503	180	200	895	78

Operation

1. Initial closed state: The valve is closed by the spring force while the inlet pressure is lower than the set pressure.
2. Start to discharge: As the inlet pressure increases, the force pushing up the valve becomes closer to the spring force pushing down the valve, and the product starts to discharge.
3. Discharge: When the fluid pressure becomes larger than the spring force due to the increased inlet pressure and being supported by the valve cover, the valve opens.
4. Closing: After the fluid is discharged to the air, the inlet pressure decreases. The valve closes when the fluid pressure becomes smaller than the spring force.
5. Discharge by lever: Discharge check can be done by pulling up the lever when the inlet pressure is 80% of the set pressure or higher.

Certified Capacity Table

For Steam (saturation temperature) <EN ISO 4126-1: 2013> (kg/h)

Nominal size	0.1 MPa	0.3 MPa	0.5 MPa	0.7 MPa	0.9 MPa	1.1 MPa	1.3 MPa	1.6 MPa
20A	224	451	676	899	1120	1341	1560	1889
25A	348	699	1047	1392	1735	2077	2416	2926
32A	573	1151	1723	2291	2856	3418	3977	4816
40A	877	1762	2639	3509	4374	5235	6090	7376
50A	1393	2799	4191	5572	6946	8313	9671	11713
65A	2332	4684	7015	9326	11625	13913	16187	19604
80A	3511	7052	10561	14039	17501	20945	24368	29513
100A	5457	10959	16411	21815	27195	32547	37866	45859

For Air (20 ℃) <EN ISO 4126-1: 2013> (kg/h)

Nominal size	0.1 MPa	0.3 MPa	0.5 MPa	0.7 MPa	0.9 MPa	1.1 MPa	1.3 MPa	1.6 MPa
20A	353	724	1095	1466	1837	2208	2578	3135
25A	548	1122	1696	2270	2844	3419	3993	4854
32A	902	1847	2792	3737	4682	5627	6572	7989
40A	1381	2828	4276	5723	7170	8617	10065	12235
50A	2193	4491	6790	9088	11386	13684	15982	19430
65A	3671	7518	11364	15211	19057	22903	26750	32520
80A	5527	11317	17108	22898	28689	34479	40269	48955
100A	8588	17586	26584	35581	44579	53577	62574	76071

(Note: Intermediate pressure values are available in the full manual tables.)

Installation and Precautions

WARNING

1. Do not install any closing device such as a stop valve at the inlet or outlet side of the product. Resistance from the closing device may cause insufficient discharge.
2. Connect a discharge pipe at the outlet side of the product, and lead it to a place where there is no risk of physical damage even if the fluid blows out.
3. Do not apply a viscous fluid that may cause fixation of the valve and valve seat.

INSTALLATION CAUTIONS

• Install the product vertically with the cap upward.
• The inner diameter of the pipe mount and discharge pipe should be equal to or larger than that of each inlet and outlet of the product.
• Give proper support to the outlet piping that is subjected to the reaction force against the exhaust flowing up through the exhaust pipe connected to the product.
• When hot fluid is applied, install the outlet piping in a way that the product is free from the stress caused by the thermal expansion of the equipment or by the thermal expansion/compression of the discharge pipe.

Maintenance

Daily Inspection:

• Ensure there is no corrosion or crack on the product.
• Check for no leakage from the product at normal working pressure.
• Check for no leakage from the mounting connection.

Periodic Inspection (Monthly):

1. Check that the product is securely connected to both inlet and outlet piping without any loose connection.
2. Increase the fluid pressure to the set pressure and check that the product operates properly.
3. Increase the fluid pressure to 80% of the set pressure or higher, and check that the fluid discharges by operating the lever.

Troubleshooting

Trouble	Cause	Remedy
Leakage from outlet	Foreign substance is stuck between valve and valve seat.	Operate the product to eliminate foreign substances.
	Sealing surface of valve seat is damaged.	The product needs to be replaced.
	Vibration transmitted from the piping causes malfunction.	Do not use the product on equipment that vibrates excessively.
Blows at a pressure lower than the set pressure	Product specifications are not consistent with usage conditions.	Check the set pressure value shown on the nameplate.
	Pressure gauge is out of order.	Calibrate or replace the pressure gauge.
Does not blow at the set pressure	Sliding parts of the valve and valve seat do not move smoothly.	The product needs to be disassembled and cleaned.
	There is a back pressure at the piping of the product outlet.	Remove the back pressure by changing the piping layout.
The lever does not lift up	Inlet pressure is too low.	Increase the inlet pressure to 80% of the set pressure or higher.