The Nitto Kohki Mini Cupla is a compact quick coupling in brass for miniature pneumatic applications. The programme covers 24 items in several configurations: PH (metric internal thread, straight), PF (metric internal thread, flat), PFF (flange port), and PHB (with branch) in nominal sizes 22, 25, and 33. The Mini Cupla is engineered for minimum installation size with reliable operation.
⚙Brass construction - lightweight, corrosion-resistant, suitable for compressed air and mild media
↕Four port configurations - PH, PF, PFF, and PHB for different assembly situations
⬡24 items - complete Mini Cupla programme for miniature pneumatics
✦PHB with branch - T-shaped manifold port for multiple outlets
Type
Port
Nominal size
Material
22PH / 25PH / 33PH
Internal thread, straight
22, 25, 33
Brass
22PF / 25PF / 33PF
Internal thread, flat
22, 25, 33
Brass
22PFF
Flange port
22
Brass
22PHB / 25PHB
Internal thread with branch
22, 25
Brass
35PH
Internal thread, straight
35
Brass
Typical applications: Miniature pneumatics in laboratory instruments, medical equipment, and analytical instruments, compressed-air supply to miniature cylinders and micro-dosing valves, pneumatic control circuits in sensor and measurement technology, and compressed-air connections in space-critical installations in robotics and precision mechanics.
Technical data from the manufacturer catalogue
Series
MINI CUPLA / LINE CUPLA MINI
Body material
Brass
Seal material
Nitrile rubber (NBR)
Max working pressure
0.7 MPa {7 kgf/cm2, 7 bar, 102 PSI}
Working temperature
Nitrile rubber (NBR): -20 °C to +80 °C
Valve structure
One-way shut-off
Applicable fluids
Oxygen, Fuel Gas
Vacuum service
Not suitable for vacuum application in either connected or disconnected condition.
Size range
Thread 1/8 inch, 1/4 inch, 3/8 inch / M16, W12.5-20; Hose barb 1/4 inch, 5/16 inch, 3/8 inch
Catalogue page
C01en-b, 69
Operating principle
On disconnection the valve in the socket closes the supply line. The fluid left in the plug escapes.Connecting sequence of a ball locking quick connect coupling.
From cylinders to torches, all piping connections associated with welding and cutting equipment are push-to-connect operations.
Double-lip seal prevents minor leak during connection.
Oxygen and fuel gas CUPLA have different sizes to prevent accidental interconnection.
Pressure loss is minimized to achieve higher flow rate.
Various types of end configurations have been standardized to comply with a wide range of welding and cutting equipment applications.
Sockets themselves or plugs themselves are interchangeable with MINI CUPLA SUPER's counterparts.
LINE CUPLA MINI is also available for multiple piping.
Push-to-connect operation (built-in automatic shut-off valve in socket).
All models of the series
PH - Hose barb
Model
Coupling part
Application
Brass (g)
L
H
A
C
T
øB
22PH
Plug
1/4 inch hose
16
55
11
28
23.5
7.8
5
25PH
Plug
5/16 inch hose
19
55
11
28
23.5
9
5
33PH
Plug
3/8 inch hose
22
57
14
28
25.5
10.5
7.5
35PH
Plug
5/16 inch hose
20
57
14
28
25.5
9
6
SH - Hose barb
Model
Coupling part
Application
Brass (g)
L
øD
A
T
øB
22SH
Socket
1/4 inch hose
52
(65)
(19.8)
29
7.8
5
25SH
Socket
5/16 inch hose
55
(65)
(19.8)
29
9
5
33SH
Socket
3/8 inch hose
69
(66)
(22.6)
29
10.5
7.5
35SH
Socket
5/16 inch hose
67
(66)
(22.6)
29
9
6
PF - Female thread for torch connection
Model
Coupling part
Application
Brass (g)
L
C
T
øB
øH(WAF)
22PF
Plug
For oxygen torch side
31
(43)
23.5
M16x1.5
5
Hex.19
22PFF
Plug
For oxygen torch side
29
(43.5)
23.5
G 1/4
5
Hex.17
25PF
Plug
For oxygen torch side
26
(43.5)
23.5
W12.5-20
5
Hex.17
33PF
Plug
For fuel gas torch side
36
(44.5)
25.5
M16x1.5 left-hand thread
7.5
Hex.19
SF - Female thread for cylinder connection
Model
Coupling part
Application
Brass (g)
L
øD
T
øB
øH(WAF)
22SF
Socket
For oxygen gauge side
80
(52)
(19.8)
M16x1.5
5
Hex.19
33SF
Socket
For fuel gas gauge side
96
(54)
(22.6)
M16x1.5 left-hand thread
5
Hex.19
PHB - Hose barb with backflow stop valve
Model
Coupling part
Application
Brass (g)
L
H
A
C
T
øB
22PHB
Plug
1/4 inch hose
31
(69.6)
15.5
28
23.5
7.8
4.5
25PHB
Plug
5/16 inch hose
34
(69.6)
15.5
28
23.5
9
4.5
33PHB
Plug
3/8 inch hose
41
(70.6)
15.5
28
25.5
10.5
4.5
35PHB
Plug
5/16 inch hose
39
(70.6)
15.5
28
25.5
9
4.5
SM - Male thread
Model
Coupling part
Application
Brass (g)
L
øD
T
øB
øH(WAF)
22SM
Socket
Rc 1/4
51
(52)
(19.8)
R 1/4
7.5
12
33SM
Socket
Rc 3/8
77
(55)
(22.6)
R 3/8
10
14
PFB - Female thread with backflow stop valve for torch connection
Model
Coupling part
Application
Brass (g)
L
C
T
øB
øH(WAF)
22PFB
Plug
For oxygen torch side
36
(48.5)
23.5
M16x1.5
4.5
Hex.19
33PFB
Plug
For fuel gas torch side
41
(49)
25.5
M16x1.5 left-hand thread
4.5
Hex.19
PMT - Male thread
Model
Coupling part
Application
Brass (g)
L
C
T
øB
øH(WAF)
21PMT
Plug
Rc 1/8
22
43.5
24
R 1/8
5
Hex.14
22PMT
Plug
Rc 1/4
27
45
24
R 1/4
5
Hex.14
LM - LINE CUPLA MINI, for three port branch piping
Model
Coupling part
Application
Brass (g)
LM-32
socket block
Three port branch piping; supply port 1/4 inch for oxygen or 3/8 inch for fuel gas
4,300
Dimensions in millimetres. Values in brackets apply in the connected condition.
Legend: L = overall length; H = width across flats or outside dimension; D = socket outside diameter; A = hose barb length; C = sleeve dimension; T = thread or barb size; B = bore
Series comparison
Series
Max working pressure
Size range
Valve structure
Applicable fluids
MINI CUPLA / LINE CUPLA MINI
7 bar
Thread 1/8 inch, 1/4 inch, 3/8 inch / M16, W12.5-20; Hose barb 1/4 inch, 5/16 inch, 3/8 inch
One-way shut-off
Oxygen, Fuel Gas
COMPACT ZEROSPILL CUPLA
10 bar
Thread 1/8 inch, 1/4 inch
Two-way shut-off (Spill Reduction)
Air, Water
CUPLA HOSE with FULL BLOW CUPLA
10 bar
Hose size ø5 mm×ø8 mm, ø6.5 mm×ø10 mm, ø8.5 mm×ø12.5 mm
One-way shut-off
Air
FLOW MONITOR
10 bar
Rc 3/8 and Rc 1/2
-
Water
ANTI-VIBRATION PLUG HOSE
15 bar
R 1/4 (SHA-3-2R), R 3/8 (SHA-3-3R)
One-way shut-off
Air
HI CUPLA BL
15 bar
1/4 inch, 3/8 inch, 1/2 inch (thread and hose barb); SN type for urethane hose: for 6.5 x 10 mm, 8 x 12 mm and 8.5 x 12.5 mm hose
MINI CUPLA is the series to pick for the oxygen and fuel gas lines of gas welding and gas cutting equipment, because the oxygen and the fuel gas versions are made in different sizes so that the two gases cannot be interconnected by accident. Its working pressure is 0.7 MPa {7 kgf/cm2}, below the 1.0 MPa {10 kgf/cm2} of COMPACT ZEROSPILL CUPLA and PURGE LINE CUPLA and below the 1.5 MPa {15 kgf/cm2} of HI CUPLA BL, NUT CUPLA, LOCK CUPLA 200, HI CUPLA Two Way Type, ROTARY LINE CUPLA, ROTARY FULL BLOW LINE CUPLA and ROTARY PLUG, so compressed air lines at those pressures belong to one of those series. MINI CUPLA is one-way shut-off like them; where both sides have to close with reduced spillage, COMPACT ZEROSPILL CUPLA is the two-way shut-off alternative.
Sockets 22SH, 25SH, 22SF and 22SM all give the same values: 19.6 with plugs 22PH, 25PH, 22PF, 22PFF, 25PF, 21PMT and 22PMT; 15.9 with plugs 22PHB, 25PHB and 22PFB.
Plugs with backflow stop valve in MINI CUPLA (22PHB, 25PHB, 22PFB, 33PHB, 35PHB, 33PFB) are designed exclusively for gas welding and cutting, to prevent occurrence of gas mixing. Possible backflow of gas during operation can be stopped by cutting the backflow into the cylinder or line. Such valve is adopted in both fuel gas and oxygen plug. The operating pressure value printed with the sketch is not legible in the extracted text.
LINE CUPLA MINI LM-32 contents
Supply port 1/4 inch for oxygen, 3/8 inch for fuel gas, each 1 pc. Gas outlets 22SM for oxygen, 33SM for fuel gas, each 3 pc. Accessories (plug with backflow stop valve) 22PHB for oxygen, 33PHB for fuel gas, each 3 pc. Dust caps come with the product as standard.
WAF
WAF stands for width across flats.
Flow rate
The pages give pressure - flow characteristic curves only, no tabulated flow values. Test fluid is air. For oxygen the chart runs to 1.0 m3/min (ANR) over 0 to 0.7 MPa {7 kgf/cm2}; for fuel gas it runs to 0.35 m3/min (ANR) over 0 to 0.08 MPa {0.8 kgf/cm2}. Two curves are plotted in each chart, an SF x PH combination and an SF x PHB combination.
Interchangeability and size groups
To prevent accidental connection, CUPLA for oxygen are not interchangeable with CUPLA for fuel gas. However, plugs and sockets for oxygen are interchangeable regardless of end configurations, and plugs and sockets for fuel gas are interchangeable regardless of end configurations. Interchangeable with MINI CUPLA SUPER.
Safety and application notes
Before use, please be sure to read "Safety Guide" described at the end of this book and "Instruction Sheet" that comes with the products.
Not suitable for vacuum application in either connected or disconnected condition.
Fluid must run from socket to plug.
Oxygen and fuel gas CUPLA are made in different sizes to prevent accidental interconnection; do not attempt to force a connection between them.
Plugs with backflow stop valve are designed exclusively for gas welding and cutting, to prevent occurrence of gas mixing.
Do not exceed the maximum tightening torque given for each model.
All technical data on this page is taken from the Nitto Kohki general catalogue Quick Connect Couplings C01en-b, page 69. The complete catalogue is available for download on this page.
