Yoshitake AL-260R is a closed type relief valve with a handle, designed for regulating pulsating and fluctuating pressures for large capacity pumps. It is highly effective for lines with heavy pulsation, preventing chattering and hunting while maintaining stable operation against back pressure changes. The valve features a dash-pot structure and uses stainless steel for trim parts, with a bronze spring case.

Features

• Stainless steel is used for the trim parts, and corrosion-resistant material for all wetted parts.
• Remarkably effective for lines of heavy pulsation or considerable pressure fluctuation due to unique valve structure, preventing chattering and hunting.
• Stable operation can be maintained against back pressure changes produced in continuous blow.
• Equipped with a handle for easy pressure changes.

Specifications

Feature	Specification
Structure	Closed type with a handle
Application	Cold and hot water, Oil, Other non-dangerous fluids (Less than 20 cSt)
Working Pressure	0.05 - 1.0 MPa
Maximum Temperature	90°C
Spring Case Material	Cast bronze
Valve, Valve Seat Material	Stainless steel
Connection	JIS Rc screwed

Dimensions and Weights

Nominal Size	d	L (mm)	H1 (mm)	H (mm)	Weight (kg)
15A	Rc 1/2	34	41.0	185	1.0
20A	Rc 3/4	38	45.0	190	1.2
25A	Rc 1	43	51.5	200	1.5
32A	Rc 1-1/4	50	63.5	245	2.2
40A	Rc 1-1/2	60	68.5	280	3.2
50A	Rc 2	75	80.0	315	5.3

Discharge Capacity

The following table outlines the blow-out capacity for the main pressure with an accumulation of 25%.

Nominal Size	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	0.14	0.20	0.29	0.35	0.41	0.46	0.50	0.54	0.58	0.62	0.65
20A	0.20	0.29	0.41	0.51	0.59	0.66	0.72	0.78	0.83	0.88	0.93
25A	0.49	0.69	0.98	1.20	1.38	1.54	1.69	1.83	1.96	2.07	2.19
32A	1.14	1.62	2.29	2.81	3.24	3.63	3.97	4.29	4.59	4.87	5.13
40A	1.79	2.53	3.58	4.39	5.07	5.67	6.21	6.71	7.17	7.61	8.02
50A	2.80	3.96	5.60	6.86	7.92	8.86	9.71	10.49	11.21	11.89	12.53
(Units: m³/h)

Structure

No.	Part Name	No.	Part Name	No.	Part Name
1	Spring case	7	Top spring plate	13	Rivet
2	Valve seat	8	Adjusting screw	14	Name plate
3	Valve	9	Lock nut	15	O ring
4	Spindle	10	Cap	16	Handle
5	Spring	11	Gasket	17	Valve Case
6	Bottom spring plate	12	Gasket

Installation

Warning

• Do not install any closing device such as a stop valve at inlet or outlet sides of the product.
• 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.
• Do not apply the product to devices which do not allow any valve seat leakage. The product has allowable valve seat leakage.
• When installing, tighten the valve case with a spanner. Do not adjust its direction by rotating the outlet piping.

Piping Example

Troubleshooting

Trouble	Cause	Remedy
Blows at a pressure lower than the set pressure	1. The product specifications are not consistent with the use condition. 2. The pressure gauge is out of order. 3. Foreign substance or scale stuck on contact surface between the valve and valve seat. 4. Damage on the contact surface. 5. The product does not keep the accuracy of its set pressure.	1. Check the set pressure indication on the name plate and replace with a proper one. 2. Calibrate the pressure gauge or replace it. 3. Eliminate the foreign substance and scale. 4. The product needs to be disassembled and parts replaced. 5. The set pressure needs to be readjusted.
Does not operate at the set pressure	1. The product specifications are not consistent with the use condition. 2. The product does not keep the accuracy of its set pressure. 3. The pressure gauge is out of order. 4. Sliding parts do not move smoothly. 5. There is a back pressure at the piping of the product outlet.	1. Replace with a proper one. 2. The set pressure needs to be readjusted. 3. Calibrate the pressure gauge or replace it. 4. The product needs to be disassembled and cleaned. 5. Remove the back pressure.

Procedure for Set Pressure Adjustment

1. Loosen the lock nut by turning it counterclockwise by hand.
2. To increase the set pressure, turn the handle clockwise. To decrease the set pressure, turn the handle counterclockwise. Each turn must be slow and 1/4 to 1/3 of full turn. Confirm operation each time.
3. After the completion of adjustment, tighten the lock nut by turning it clockwise by hand.

Set Pressure Range

Nominal Size	A	B	C	D	E	F
15A	0.05~0.2	0.21~0.4	0.41~0.55	0.56~0.75	0.76~1.0	—
20A	0.05~0.2	0.21~0.35	0.36~0.45	0.46~0.6	0.61~0.75	0.76~1.0
25A	0.05~0.2	0.21~0.35	0.36~0.45	0.46~0.55	0.56~0.8	0.81~1.0
32A	0.05~0.2	0.21~0.4	0.41~0.65	0.66~1.0	—	—
40A	0.05~0.2	0.21~0.4	0.41~0.65	0.66~0.8	0.81~1.0	—
50A	0.05~0.2	0.21~0.4	0.41~0.65	0.66~0.8	0.81~1.0	—