Datasheet
ARP20K/30K/40K
When the inlet pressure is higher than the set pressure, the check valve w closes and operates as a normal regulator (Figure 1).
When the inlet pressure is shut off and released, the check valve w opens and the pressure in the diaphragm chamber q is released to
the inlet side (Figure 2).
This lowers the pressure in the diaphragm chamber q and the force generated by the pressure regulator spring e pushes down the
diaphragm. Valve r opens through the stem, and the outlet pressure is released to the inlet side (Figure 2).
Working Principle (Regulator with Backflow Function)
Figure 2 BackflowFigure 1 Normal
w
w
Pressure in
diaphragm chamber
Inlet pressure
(IN side)
CS M
2
OUT
1
I N
A
A
A-A
w
Pressure in
diaphragm chamber
Inlet pressure
(IN side)
r
q
e
IN
(Inlet pressure)
OUT
(Outlet pressure)
r
q
e
IN
(Inlet pressure)
OUT
(Outlet pressure)
Series ARP20/30/40
Dimensions
Model
Optional specifications
Square embedded type
pressure gauge
Digital
pressure switch
Round type
pressure gauge
Note 3)
Bracket mount dimension Panel mount
28
28
28
H
29.5
30.5
35
J
27.8
27.8
27.8
H
40
41
45
J
ø37.5
ø37.5
ø42.5
H
66
67
74
J
30
41
50
M
34
40
54
N
47
44
54
Q
5.4
6.5
8.5
R
15.4
8
10.5
S
55
53
70
T
2.3
2.3
2.3
U
28
31
35.5
V
28.5
38.5
42.5
W
14
19
21
Y
6
7
7
Z
ARP20
(
K
)
ARP30
(
K
)
ARP40
(
K
)
Standard specifications
ARP20
(
K
)
ARP30
(
K
)
ARP40
(
K
)
Model
1/8, 1/4
1/4, 3/8
1/4, 3/8, 1/2
P1 P2 A
1/8
1/8
1/4
40
53
70
B
Note 1)
98
117
148
C
27
29
41
D
28.5
29.5
34
F
M28 x 1
M38 x 1.5
M42 x 1.5
J
28.5
Note 2)
29.5
34
K
2
2.5
1
Panel fitting dimension
Pressure Gauge Option
H
H
Digital pressure switch
(Electrical entry: Wiring top entry)
Digital pressure switch
(Electrical entry: Wiring bottom entry)
Square embedded type
pressure gauge
Option
Dimensions
Round type
pressure gauge
J
Center of piping
J
Center
of piping
J
Center of piping
H
H
J
Center of piping
Y
W
Z
OUT
IN
S
R
T
N
A
P2
Pressure gauge port size
F
OUT
IN
(Option)
Pressure gauge
D
K
J
U
M
B
Q
C
V
Bleed port
2 x P1 Port size
Bracket
(Option)
Plate thickness
ARP20(K), ARP30(K): Max. 3.5
ARP40(K): Max.
5
Note 1) The total length of B direction is the length when the filter regulator knob is unlocked.
Note 2) For ARP20(K) only, the position of the pressure gauge is above the center of the piping.
Note 3) For dimensions of the round-type pressure gauge for special applications, please contact SMC.
∗ The dimensions are for special applications
(not including round-type pressure gauge).
The dimensions for special applications are
the same as those of the standard product.
However, as for the 10-, 20-series, a fitting
is attached to the bleed port and it protrudes
from the face with the OUT port by approx.
11 mm.
Direct Operated Precision Regulator/Modular Style
Series ARP20/30/40
9