Yoshitake AL-300T and AL-301T are closed-type, lift safety relief valves designed for air, cold and hot water, oil, and other non-dangerous fluids. The valves feature a simple structure that is easy to maintain and adjust. The inclusion of a polytetrafluoroethylene (PTFE) disc between the valve and valve seat ensures excellent airtightness and completely prevents leakage.

Features

1. Due to using a valve disc of polytetrafluoroethylene material on the valve parts, the airtightness of the valve seat is excellent.
2. The trim parts (valve, valve seat) of the AL-301T are made of stainless steel material with outstanding corrosion resistance.

Specifications

Model	AL-300T	AL-301T
Structure	Closed type	Closed type
Application	Air, Cold and hot water, Oil, Other non-dangerous fluids	Air, Cold and hot water, Oil, Other non-dangerous fluids
Working pressure	0.05-1.0 MPa	0.05-1.3 MPa *1
Maximum temperature	150°C	150°C
Material (Valve case, spring case)	Ductile cast iron	Ductile cast iron
Material (Valve, valve seat)	Cast bronze and PTFE	Stainless steel and PTFE
Connection	JIS 10K FF flanged *3	JIS 10K FF flanged *3

INFO

*1: Please contact us if working pressure is between 1.31 MPa and 1.6 MPa. *3: JIS 16K FF flanged when working pressure is more than 1.0 MPa.

Dimensions and Weights

Nominal size	L (mm)	H (mm)	H1 (mm)	d (mm)	Flow area (mm²)	Weight (kg)
15A	90	245	108	29	66.1	4.7
20A	90	245	108	29	66.1	5.0
25A	90	245	108	29	66.1	6.2
32A	91	285	115	37	107.6	8.6
40A	91	285	115	37	107.6	8.8
50A	105	311	132	50	196.4	12.6

Parts List

No.	Part name	No.	Part name
1	Spring case	9	Adjusting screw
2	Valve case	10	Lock nut
3	Valve seat	11	Name plate
4	Valve	12	Stud bolt & nut
5	Top spring plate	13	Gasket
6	Bottom spring plate	14	Gasket
7	Spring	15	Disc
8	Cap	16	Rivet

Operation

Opening operation: As the inlet pressure approaches the opening pressure, the force of fluid pushing up the valve approaches the force pressing down the valve. The safety relief valve starts to discharge when the inlet pressure reaches around 3% below the opening pressure, and the fluid accumulates gradually on the pressure groove. When the fluid pressure reaches the opening 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 fluid lift force is lowered. At this point, the repelling force of the spring becomes larger than the force of fluid lift and thus the valve closes.

Certified Capacity Table for AL-300T / AL-301T

For air (20°C) <Pressure vessel structure standard> (kg/h)

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	1.1 MPa	1.2 MPa	1.3 MPa
15A	84	109	159	213	268	322	377	432	486	541	595	650	704	759
20A	84	109	159	213	268	322	377	432	486	541	595	650	704	759
25A	84	109	159	213	268	322	377	432	486	541	595	650	704	759

For water (accumulation: 25%) <Yoshitake standard> (m³/h)

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	1.1 MPa	1.2 MPa	1.3 MPa
15A	0.8	1.1	1.6	2.0	2.3	2.6	2.8	3.1	3.3	3.5	3.7	3.9	4.0	4.2
20A	0.8	1.1	1.6	2.0	2.3	2.6	2.8	3.1	3.3	3.5	3.7	3.9	4.0	4.2
25A	0.8	1.1	1.6	2.0	2.3	2.6	2.8	3.1	3.3	3.5	3.7	3.9	4.0	4.2

Installation

WARNING

1. Do not install any closing device such as a stop valve at the inlet and outlet sides of the product.
2. Do not disassemble the product unnecessarily. Failure to follow this notice may prevent the product from functioning properly and lead to danger.
3. Lead the outlet pipe to a place where there is no risk of physical damage even if fluid blows out. Failure to follow this notice may result in injury and scalds in case of fluid blow out.
4. Do not apply viscous fluid that may make fixation of the valve and valve seat.

Installation Recommendations

1. Before installing the product, remove foreign substances and scale from the piping.
2. When installing the product, match the direction of fluid flow with the inlet and outlet of the product respectively.
3. Install the product in a way that excessive load, torque, or vibration cannot be applied to the product.
4. The inner diameters of the pipe mount and of the exhaust pipe shall be equal to or larger than those of each inlet and outlet of the product.
5. Install the product in a posture in which the stem of the adjusting screw is vertical to the ground and the cap faces upward. Preferably attach the product directly to a pressure vessel. Place the product in a position where maintenance and inspection can be done easily.

Maintenance

DANGER

Disassembly and inspection must be done by experienced professionals. Completely discharge inside pressure from the product, piping, and equipment prior to disassembly or inspection. When fluid is hot, cool down the product to the condition that it can be touched with bare hands. Failure to follow this notice may result in scalds or injury due to the residual pressure.

Opening pressure adjustment:

1. Turn the cap counterclockwise and remove it.
2. Loosen the lock nut by turning it counterclockwise using a spanner.
3. To increase the set pressure, turn the adjusting screw clockwise using a spanner.
4. To decrease the set pressure, turn the adjusting screw counterclockwise using a spanner.
5. After adjustment is completed, tighten the lock nut and then the cap.

Disassembly:

1. Remove the cap and loosen the lock nut. Measuring the height from the top surface of the adjusting screw to that of the spring case before disassembly can provide a guide for reassembly.
2. Loosen the adjusting screw by turning it counterclockwise to the condition that the spring is free of load.
3. Remove the spring case by loosing the stud bolts and nuts. Then remove the top spring plate, spring, bottom spring plate, and the valve.

Reassembly: Clean the parts before reassembling. Reassemble them in the reverse order of disassembly.