Yoshitake AL-27 User manual

■EPDT-351■
MODEL AL-27
SAFETY RELIEF VALVE
PRODUCT MANUAL .
Thank you very much for choosing the Yoshitake’s product. To ensure the correct and safe use of the
product, please read this manual before use. This manual shall be kept with care for future references.
The symbols used in this manual have the following meanings.
Warning
This symbol indicates a potentially hazardous situation that, if not avoided,
could result in death or serious injury.
Caution
This symbol indicates a hazardous situation that, if not avoided, may result in
minor or moderate injury or may result in only property damage.
Table of Contents
1. Usage of the Product·················································· 1
2. Specifications···························································· 1
3. Dimensions and Weight ·············································· 2
4. Structure ································································ 3
5. Operation ······························································· 3
6. Nominal Size Selection Chart ······································· 4
7. Installation···························································· 7-12
7.1 Fitting pipe base ·················································· 8
7.2 Discharge pipe ···················································· 8
7.3 Set pressure adjustment···································· 9-12
8. Maintenance····························································12
8.1 Daily inspection ··················································12
8.2 Periodic inspection··············································12
8.3 Troubleshooting············································· 13-14
Warranty Information

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1
1.
Usage of the Product
The AL-27 is a relief valve for pressure control in a pump system in which large pressure pulsation or
fluctuation occurs.
2
. Specifications
Model AL-27
Structure Closed type
Application Cold and hot water, Oil (heavy oil A, heavy oil B, kerosene),
other non-dangerous fluids (20 cSt or less)
Working pressure 0.05 - 1.6 MPa
Max. temperature 120°C
Connection JIS Rc screwed
Nominal size 15-50A
Material Spring case Ductile cast iron
Valve, valve seat Stainless steel
Warning
1. Do not apply the product to equipment or devices which do not allow any valve seat leakage.
* The product has allowable valve seat leakage and does not close completely (valve seat leakage
cannot be zero).
2. Do not use the product for equipment or device which vibrates excessively.
* Failure to follow this notice may result in malfunction.
Caution
Please confirm that the indications on the product correspond with the specifications
of the ordered product model before use.
* If they are different, do not use the product and contact us.

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2
3
. Dimensions and Weight
Figure 1. Dimensions
Table 1. Dimensions and weight
(mm)
Nominal
Size d L H1H
Weight(kg)
15A
Rc 1/2 40 40 143 0.9
20A
Rc 3/4 45 50 162 1.3
25A
Rc 1 50 60 182 1.7
32A
Rc 1 1/4 60 70 220 2.9
40A
Rc 1 1/2 65 75 238 3.9
50A
Rc 2 80 85 272 6.4

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3
4
. Structure
Figure 2. Structure
Table 2. Parts list
7 Spring plate
6 Spring 13 Gasket
5 Spindle 12 Gasket
4 Valve 11 Cap
3 Valve seat 10 Lock nut
2 Body 9 Adjusting screw
1 Spring case 8 Spring plate
№ Part name № Part name
5
. Operation
As the inlet pressure approaches the set pressure, the force of fluid pushing up the valve [4] approaches the
force of the spring [6] pressing down the valve [4]. When the inlet pressure increases further, the valve [4]
opens and discharges the fluid. The valve lift changes responding to the inlet pressure and controls it.
(See Figure 2.)
Outlet
Inlet

■EPDT-351■
4
6
. Nominal Size Selection
Chart
The flow rate of each size with 25% of accumulation (excess to the set pressure) is shown in Figure 3.
See Figure 4 when the accumulation is less than 25%.
Fluid: Water
Figure 3. Nominal size selection chart
Example:
When selecting the nominal size for opening pressure of 0.3 MPa and discharge capacity of
1.0 m3/h, find the intersection point (a) of the opening pressure of 0.3 MPa and the discharge
capacity of 1.0 m3/h. The intersection point (a) lies between the nominal sizes 15A and 20A,
select the larger one, 20A.
Opening pressure MPa
Discharge capacity m 3/h
Nominal size
(a)

■EPDT-351■
5
Figure 4. Approximate flow rate magnification
Figure 4 is referred to when calculating the approximate flow rate with accumulation less than 25%.
Example:
When calculating the flow rate of the size of 25A, with the opening pressure of 0.1 MPa, and
accumuation of 20%, first, find the flow rate with the accumulation of 25% by using Figure 3.
Next, find the intersection (b) with the accumulation of 20% by Figure 4 and read the value of
the approx. flow rate magnification, that is 0.8.
Multiple the opening pressure found in Figure 3 by the approximate flow rate magnification
found in Figure 4.
1.08(m3/h)×0.8(magnification)≒0.86(m3/h)
Thus, the flow rate with the accumulation of 20% is approximately 0.86 m3/h.
Table 3 shows discharge capacities at certain pressures for reference.
(b)
Accumulation %
Approx. flow rate magnification

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6
Table 3. Discharge capacity (for Reference)
[Accumulation: 25%]
(m3/h)
Nominal
size
Set pressure (MPa)
0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
15A 0.30 0.42 0.6 0.74 0.85 0.95 1.04 1.13 1.21 1.28 1.35
20A 0.49 0.69 0.98 1.20 1.39 1.55 1.70 1.84 1.96 2.08 2.20
25A 0.77 1.08 1.54 1.88 2.17 2.43 2.66 2.88 3.08 3.26 3.44
32A 1.26 1.78 2.52 3.09 3.57 3.99 4.37 4.72 5.04 5.35 5.64
40A 1.98 2.80 3.96 4.85 5.60 6.26 6.86 7.41 7.92 8.40 8.86
50A 3.09 4.37 6.18 7.57 8.74 9.77 10.71 11.57 12.37 13.12 13.83
(m3/h)
Nominal
size
Set pressure (MPa)
1.1 1.2 1.3 1.4 1.5 1.6
15A 1.42 1.48 1.54 1.6 1.65 1.71
20A 2.30 2.41 2.51 2.60 2.69 2.78
25A 3.61 3.77 3.92 4.07 4.21 4.35
32A 5.92 6.18 6.43 6.67 6.91 7.14
40A 9.29 9.70 10.10 10.48 10.85 11.21
50A 14.50 15.15 15.76 16.36 16.93 17.49

■EPDT-351■
7
7
. Installation
Warning
1. Do not install any closing devices such as a stop valve at inlet or outlet side of the product.
2. Do not apply the product to equipment or devices which do not allow any valve seat leakage.
3. 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.
* Failure to follow this notice may result in injury and scalds in case of fluid blow out.
4. Do not disassemble the product.
* Failure to follow this notice may prevent the product from functioning properly and lead to danger.
5. Securely connect the product with the piping
* Failure to follow this notice may cause fluid leakage from the connections due to vibration resulting in
injury and scalds.
6. When installing, tighten the hexagonal part of the body with a spanner.
7. Do no apply viscous fluid that may make the valve and valve seat stuck together.
* Failure to follow this notice may cause malfunction due to sticking together of the valve and valve seat.
8. When connecting a pipe to the product outlet, do not adjust the direction of the product by applying force
to the pipe.
* Failure to follow this notice may cause blowout due to damage on the thread or loose connection.
Caution
1. When installing the product, match the direction of fluid flow with the inlet and outlet of the product
respectively.
* Failure to follow this notice prevents the product from functioning properly and discharging the
pressure from the outlet and may result in damage to the device or injury.
2. Before installing the product, remove foreign substances and scale from the piping. Be careful that
sealing materials do not contaminate inside of the piping.
*Failure to follow this notice may result in malfunction. Repair due to foreign substances is charged.
3. Install the product vertically with the cap [11] upward. Taking an example with Figure 5, the product
must be vertical against water surface in the tank because the surface is horizontal.
* Failure to follow this notice prevents the product from functioning properly and discharging the
pressure from the outlet.
4. Securely support and fasten the pipes.
(See “7.1 Fitting pipe base” and “7.2 Discharge pipe.”)
* The product may be deformed and does not open or close if excessive stress is applied.
5. Do not apply flow rate with the accumulation of more than 25% to the product, or flow velocity at the
outlet side exceeds 2 m/s and causes noise and vibration.
6. Secure enough space around the product for its maintenance and inspection.

■EPDT-351■
8
7.1 Fitting pipe base (See Figure 5.)
(1) Fitting pipe base should have enough strength and rigidity against the stress induced by reaction
force in the opposite direction of the exhaust through the axis of the exhaust pipe.
(2) Equip the discharge pipe with a support to avoid excessive load, deflection, or vibration.
(3) Install the product at a place where its maintenance and inspection can be performed.
7.2 Discharge pipe (See Figure 5.)
Diameter of the discharge pipe should be the same or larger than that of the outlet of the product.
Foot valve
Pump
Flexible joint
C
heck valve
Water
tank
S
upport
Discharge
Discharge pipe
Pillar
Support
F
itting pipe
base
Fluid inlet
Figure 5. Piping example
Secure at least
500mm for
maintenance
As short as possible
Select a pipe with the same
or larger diameter than the
outlet diameter of the valve

■EPDT-351■
9
7.3 Set pressure adjustment (See 4. Structure)
Warning
To adjust the set pressure, remove the cap [11], make a 1/4 to 1/3 turn of the
adjusting screw [9] slowly as checking the pressure gauge, and check the
operation each time after turning the adjusting screw [9]. Be careful not to overturn
or the fluid may suddenly blow out. The fluid leaks from the thread of the
adjusting screw [9] while adjustment. Be careful not to get injured or scalded and
not to make the surroundings dirty. When it is difficult to adjust by yourself, please
contact us.
* Hot fluid may cause injury and scalds when it blows out.
Caution
Do not try to adjust the set pressure beyond the set pressure range defined per
spring. Please refer to Table 4. Set pressure range.
* Failure to follow this notice results in malfunction.
Table 4. Set pressure range
Nominal size Set pressure range (MPa)
Spring range A B C D E
15-50A 0.05
up to 0.2
Over 0.2
up to 0.4
Over 0.4
up to 0.65
Over 0.65
up to 1.0
Over 1.0
up to 1.6
When a set pressure is not specified, confirm if the set pressure range is proper by checking the
alphabet punched on the edge of the screwed connection. (See below.)

■EPDT-351■
10
Adjustment procedures (See 4. Structure.)
Pictures below show the product only. However, actual adjustment should be done while the product is
installed on the piping.
Warning The fluid leaks when the cap [11] is removed. Be careful not to get injured or
scalded and not to make the surroundings dirty.
2. Remove the cap [11] with a wrench by
turning it counterclockwise.
3. The lock nut [10] appears after
you remove the cap [11]. Loosen
the lock nut [10] by turning it
counterclockwise with a wrench.
1. AL-27 Safety relief valve

■EPDT-351■
11
Warning The fluid leaks from the adjusting screw [9] while adjustment.
Be careful not to get injured or scalded and not to make the surroundings dirty.
4.1 To decrease the set pressure, make
a 1/4 to 1/3 turn of the adjusting
screw [9] counterclockwise slowly
by a spanner or a wrench. Check
the operation of the product after
each turn.
4.2 To increase the set pressure,
make a 1/4 to 1/3 turn of the
adjusting screw [9] clockwise
slowly by a spanner or a wrench.
Check the operation of the product
after each turn.
5. Fasten the lock nut [10] by
turning it clockwise after the
adjustment is done.

■EPDT-351■
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8.
Maintenance
Warning
1. Do not touch the product/pipes with bare hands.
* Failure to follow this notice may result in scalds or injury when the fluid is hot.
2. Do not touch the product unless it is necessary.
* Failure to follow this notice may result in scalds or injury when the fluid is hot.
3. When checking the operation of the product, do not stand in front of the exhaust pipe or put your face
close to or touch it.
* Failure to follow this notice may result in scalds or injury due to blow-off.
4. Do not disassemble the product.
* Please contact us if any abnormal condition is observed.
Caution
1. When increasing the fluid pressure, check that there will be no problem with the equipment installed in
the piping prior to applying higher pressure.
* Failure to follow this notice may damage the equipment.
2. Completely discharge fluid from the product and piping before leaving the product not operated for a long
time.
* Failure to follow this notice may cause foreign substances and scale inside of the piping and may result
in malfunction of the product.
3. If the product is not operated for a long time, perform inspection before starting operation.
8.1 Daily inspection
Check the following while the system is in operation.
•Corrosion or crack on the product
•Outside leakage from the product
* Please contact us if any abnormal condition is observed.
8.2 Periodic inspection (once per month)
Check that there is no outside leakage from the inlet and outlet connections with the pipes, and also check
that the cap [11] is fastened securely.
* Please contact us if any abnormal condition is observed.
5. Confirm that there is no damage on the gasket
[13] prior to attaching the cap [11]. if the gasket
[13] is damaged, it must be replaced with a new
one which is recommended to be prepared in
advance.
Before attaching the gasket [13], apply paste
(Recommendation: SOLVEST No.110, STT
Inc.) to its surfaces and its inner diameter
surface, and then attach the gasket [13].
Attach the cap [11] and tighten it by turning it
clockwise. If outside leakage is observed while
relieving operation, retighten the cap [11].

■EPDT-351■
13
8.3 Troubleshooting
Trouble Cause Solution
Blows at a pressure
lower than the set
pressure.
1.
Adjusting screw [9] is loosened
due to loose lock nut [10] or
vibration applied.
1.
See
“
7.3 Set pressure adjustment.
”
2.
S
et pressure does not meet the
specifications required.
2.
Check the specifications.
The product needs to be disassembled
and some parts need to be replaced at
Yoshitake.
Please contact us.
3.
The product malfunctions due to
vibration applied.
3.
See “2. Specifications” and
“7. Installation.”
4.
The product is installed in a wrong
direction.
4.
See “7. Installati
on.”
5.
Pressure gauge is broken.
5.
Calibrate or replace the pressure gauge.
6.
The product was damaged while
transportation.
6.
Please contact
u
s.
Leakage
(Except outside
leakage)
1.
Foreign substance stuck on
contact surfaces of the valve [4]
and valve seat [3].
Or damage on the surfaces.
1.
The product needs to be disassembled and
the damaged parts need to be replaced by
Yoshitake.
2.
The product
malfunctions
due to
vibration.
2.
See “2. Specifications” and
“7. Installation.”
3.
Fluid pre
ssure reaches
or exceeds
the start to discharge pressure due
to pulsation.
3.
See “2. Specifications” and
“7. Installation.”
4.
V
alve seat [3] is loose.
4.
The product needs to be disassembled and
the damaged parts need to be replaced by
Yoshitake.
5.
The product is installed in a wrong
direct
ion.
5.
See “7. Installation.”
6.
T
he specifications do not meet the
requirements from the user.
6.
See “2. Specifications” and
“7. Installation.”
7.
The product was damaged during
transportation.
7.
P
lease contact us.
Outside leakage
1.
Damage on spring case [1], bod
y [2],
cap [11], or gaskets [12] [13] due to
abnormal pressure rise, etc.
1.
The product needs to be replaced.
Check “2. Specifications.”
2.
C
orrosion of spring case [1], body
[2], or cap [11], etc.
2.
The product needs to be replaced.
Check “2. Specifications.”
3.
C
ap [11] is loose due to vibration.
3.
See “2. Specifications” and
“7. Installation.”
4.
T
he product was damaged during
transportation.
4.
P
lease contact us.

■EPDT-351■
14
Trouble
Cause
Solution
The product does not
stop blowing.
1.
S
et pressure does not meet the
specifications required.
1.
Check the specifications.
The product needs to be disassembled
and some parts need to be replaced at
Yoshitake.
Please contact us.
2.
I
nsufficient sliding action of valve [4].
2.
The product needs to be disassembled and
the damaged parts need to be replaced by
Yoshitake.
3.
Foreign substance stuck on
contact
surfaces of the valve [4] and valve
seat [3].
3.
The product needs to be disassembled and
the damaged parts need to be replaced by
Yoshitake.
4.
The product is installed in a wrong
direction.
4.
S
ee “7. Installation.”
5.
T
he specifications do not meet the
requirements from the user.
5.
See “2. Specifications” and
“7. Installation.”
6.
T
he product was damaged during
transportation.
6.
P
lease contact us.
The product does not
blow out.
(It does not operate.)
1.
I
nsufficient sliding action of valve [4].
1.
The product needs to be disassembled and
the damaged parts need to be replaced by
Yoshitake.
2.
The product is installed in the
opposite direction. (The inlet and
outlet
are
opposite.)
2.
See “2.
Specifications” and
“7. Installation.”
3.
T
he specifications do not meet the
requirements from the user.
3.
See “2. Specifications” and
“7. Installation.”
4.
Backpressure due to
discharge
collecting pipes.
4.
Remove the
back
pressure.
5.
The product
was damaged
during
transportation.
5.
Please contact us.

2015.8
PDD-046e
Warranty Information
1. Limited warranty
This product has been manufactured using highly-advanced techniques and subjected to
strict quality control. Please be sure to use the product in accordance with instructions on
the manual and the label attached to it.
Yoshitake warrants the product to be free from any defects in material and workmanship
under normal usage for a period of one year from the date of receipt by the original user, but
no longer than 24 months from the date of shipment from Yoshitake’s factory.
2. Parts supply after product discontinuation
This product may be subject to discontinuation or change for improvement without any prior
notice. After the discontinuation of the product, Yoshitake supplies the repair parts for 5
years otherwise individually agreed.
3. This warranty does not cover the damage due to any of below:
(1) Valve seat leakage or malfunction caused by foreign substances inside piping.
(2) Improper handling or misuse.
(3) Improper supply conditions such as abnormal water pressure/quality.
(4) Water scale or freezing.
(5) Trouble with power/air supply.
(6) Any alteration made by other than Yoshitake.
(7) Use under severe conditions deviating from the design specifications
( e.g. in case of corrosion due to outdoor use).
(8) Fire, flood, earthquake, thunder and other natural disasters.
(9) Consumable parts such as O-ring, gasket, diaphragm and etc.
Yoshitake is not liable for any damage or loss caused by malfunction or defect of the product.
INTERNATIONAL DEPT.
955-5, Miyamae, Irukadeshinden, Komaki, Aichi, 485-0084, Japan
Phone: [phone] Fax: [phone]
E-mail: [e-mail]