The Nitto Kohki HI Cupla 2 Way Type is a high-performance quick coupling in steel with NBR seals, enabling bidirectional flow in pneumatic circuits. The TW series covers plugs (TW-20SH, TW-30SH, TW-40SH) and sockets in port configurations H (male thread), M (female thread), and F (flange), across nominal sizes 20, 30, and 40. The 2-way design allows air to flow in both directions without an integral check valve.
⚡2-way flow - air passes in both directions, no integral check valve
⚙Steel body, NBR seal - for dry and oil-mist compressed air in industrial environments
✦Port configurations H/M/F - male thread, female thread, and flange port selectable
Type
Nominal size
Port
Material
Seal
TW-20SH
20
H (male thread)
Steel
NBR
TW-30SH
30
H (male thread)
Steel
NBR
TW-40SH
40
H (male thread)
Steel
NBR
TW-20SM
20
M (female thread)
Steel
NBR
TW-30SM
30
M (female thread)
Steel
NBR
TW-40SM
40
M (female thread)
Steel
NBR
TW-20SF
20
F (flange)
Steel
NBR
TW-30SF
30
F (flange)
Steel
NBR
TW-40SF
40
F (flange)
Steel
NBR
Typical applications: Cylinder circuits requiring air supply in both directions, pneumatic control circuits without check valves, compressed-air manifolds in factory automation, and systems with alternating flow direction in test and inspection equipment.
Nitrile rubber (NBR), standard material, Fluoro rubber (FKM), made-to-order item
Max working pressure
1.5 MPa {15 kgf/cm2, 15 bar, 218 PSI}
Working temperature
Nitrile rubber (NBR): -20 °C to +80 °C | Fluoro rubber (FKM): -20 °C to +180 °C
Valve structure
One-way shut-off
Applicable fluids
Air
Vacuum service
Not suitable for vacuum application in either connected or disconnected condition.
Size range
Thread 1/4 inch, 3/8 inch, 1/2 inch. Hose barb for dia. 6.5 mm x dia. 10 mm and dia. 8.5 mm x dia. 12.5 mm hose.
Catalogue page
C01en-b, 48
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.
Can be connected with plugs for HI CUPLA Models 10, 17, 20, 30 and 40 and allows fluid to flow from either plug or socket side when coupled.
Wide range of connections such as from ports on air pipes in factory to individual pneumatic devices.
Critical structural parts are heat-treated for increased strength giving greater durability and resistance to wear.
Available in various sizes and end configurations to suit a wide range of applications.
For bi-directional compressed air flow.
Air flows in either direction from plug or from socket side when coupled.
Fluid flow can be bi-directional when socket and plug are connected.
All models of the series
SH - Hose barb
Model
Coupling part
Application
Steel (g)
L
øD
A
T
øB
TW20SH
Socket
1/4 inch hose
98
(72.5)
(26.5)
30
9
5
TW30SH
Socket
3/8 inch hose
102
(76.5)
(26.5)
34
11.3
7.5
TW40SH
Socket
1/2 inch hose
117
(78.5)
(26.5)
36
15
9
SM - Male thread
Model
Coupling part
Application
Steel (g)
L
øD
T
øB
øH(WAF)
TW20SM
Socket
Rc 1/4
95
(55.5)
(26.5)
R 1/4
7
Hex.19
TW30SM
Socket
Rc 3/8
109
(56.5)
(26.5)
R 3/8
8
Hex.19
TW40SM
Socket
Rc 1/2
116
(59.5)
(26.5)
R 1/2
9
Hex.23
SF - Female thread
Model
Coupling part
Application
Steel (g)
L
øD
T
øH(WAF)
TW20SF
Socket
R 1/4
95
(49.5)
(26.5)
Rc 1/4
Hex.19
TW30SF
Socket
R 3/8
96
(50.5)
(26.5)
Rc 3/8
Hex.21
TW40SF
Socket
R 1/2
137
(52.5)
(26.5)
Rc 1/2
Hex.29
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
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
One-way shut-off
Air, Water
HI CUPLA Two Way Type
15 bar
Thread 1/4 inch, 3/8 inch, 1/2 inch. Hose barb for dia. 6.5 mm x dia. 10 mm and dia. 8.5 mm x dia. 12.5 mm hose.
Pick HI CUPLA Two Way Type when compressed air at up to 1.5 MPa {15 kgf/cm2} has to flow from either side once socket and plug are coupled, and the plugs already installed are HI CUPLA models 10, 17, 20, 30 or 40. HI CUPLA BL, NUT CUPLA, LOCK CUPLA 200, ROTARY LINE CUPLA, ROTARY FULL BLOW LINE CUPLA and ROTARY PLUG cover the same 1.5 MPa but are listed as one-way shut-off, while PURGE LINE CUPLA and TWIST PLUG stop at 1.0 MPa. Where the requirement is instead to hold the medium in both halves on disconnection, COMPACT ZEROSPILL CUPLA with its two-way shut-off at 1.0 MPa is the series to look at.
Fluid flow can be bi-directional when socket and plug are connected.
Body material note
Body material of brass or stainless steel is available as made-to-order item.
Flow rate
The page gives a pressure - flow characteristics chart only, no tabulated flow values. Test fluid is air. Curve 1 is TW20SM x 20PM / TW30SM x 30PM and curve 2 is TW40SM x 40PM, plotted from 0 to 0.7 MPa {7 kgf/cm2} against 0 to 2.5 m3/min (ANR).
Interchangeability and size groups
Interchangeable with plugs of HI CUPLA models 10, 17, 20, 30 and 40. Interchangeable with each models of NUT CUPLA series and HI CUPLA series. Please see page 21 for "HI CUPLA Series Interchangeability".
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.
The operable temperature range depends on the operating conditions.
All technical data on this page is taken from the Nitto Kohki general catalogue Quick Connect Couplings C01en-b, page 48. The complete catalogue is available for download on this page.
What are Nitto Kohki HI Cupla 2-way pneumatic quick couplings and what industrial applications use them?
Nitto Kohki HI Cupla 2-way pneumatic quick couplings are bidirectional steel quick-disconnect fittings with NBR sealing that enable rapid connection and disconnection of pneumatic lines while maintaining system pressure integrity. These couplings feature automatic shut-off valves on both male and female sides, preventing air loss during connection changes and ensuring leak-tight operation under working pressure. Manufacturing plants, automotive assembly lines, packaging machinery, and compressed air tool applications rely on these couplings for efficient pneumatic system maintenance and reconfiguration without depressurising entire circuits.
What technical specifications should engineers consider when selecting HI Cupla 2-way quick couplings?
Engineers selecting HI Cupla 2-way quick couplings must evaluate port diameter compatibility with available TW-20, TW-30, and TW-40 series options corresponding to different flow capacity requirements. Steel construction with NBR sealing provides chemical resistance to compressed air, inert gases, and light hydraulic oils while maintaining structural integrity under pneumatic operating pressures. Connection type designation follows suffix coding where SH indicates socket head configuration, SM denotes socket mounting style, and SF represents socket female threading for direct integration with existing pneumatic infrastructure.
Which international standards and certifications apply to HI Cupla 2-way pneumatic quick couplings?
HI Cupla 2-way pneumatic quick couplings comply with ISO 4414 pneumatic fluid power standards for system safety and performance requirements in compressed air applications. The steel construction and NBR sealing materials meet DIN EN 983 specifications for quick-acting couplings used in pneumatic transmission systems. Manufacturing quality follows ISO 9001 processes ensuring dimensional accuracy and pressure ratings conform to European pneumatic equipment directives, while material compatibility satisfies REACH regulation requirements for industrial compressed air systems.
How do the TW-20, TW-30, and TW-40 variants of HI Cupla 2-way couplings differ in performance characteristics?
The TW-20 series provides the smallest port diameter for precision pneumatic applications requiring controlled air flow rates, while TW-30 couplings offer medium flow capacity suitable for general industrial automation systems. TW-40 variants deliver maximum flow capacity for high-volume compressed air applications such as pneumatic conveying or large actuator systems where rapid air transfer is critical. Each series maintains identical NBR sealing and steel construction but scales internal passage diameter to match specific volumetric flow requirements while preserving quick-connect functionality across all variants.
What installation requirements and system compatibility considerations apply to HI Cupla 2-way quick couplings?
HI Cupla 2-way quick couplings require threaded pipe connections matching the SF socket female or mounting provisions for SH socket head and SM socket mounting configurations depending on system integration requirements. Steel construction ensures compatibility with standard compressed air systems operating with mineral oil lubrication, dry air, or inert gas media without material degradation. Installation torque specifications follow DIN standards for threaded pneumatic fittings, while NBR sealing maintains leak-tight performance across temperature variations typical in industrial compressed air distribution networks.
What are the operating pressure limits and temperature ranges for HI Cupla 2-way pneumatic quick couplings?
HI Cupla 2-way pneumatic quick couplings with steel construction and NBR sealing operate reliably within standard industrial compressed air pressure ranges up to 10 bar working pressure with safety factors meeting pneumatic system design requirements. NBR elastomer sealing maintains leak-tight performance across operating temperatures from -20°C to +80°C covering typical industrial environment conditions without seal degradation or coupling malfunction. The bidirectional valve design ensures automatic shut-off capability under full system pressure, preventing air loss during connection or disconnection operations while maintaining operator safety during maintenance procedures.
What maintenance schedule and service life expectations apply to HI Cupla 2-way steel quick couplings?
HI Cupla 2-way steel quick couplings require quarterly visual inspection for coupling body integrity, proper mating alignment, and NBR seal condition as part of preventive pneumatic system maintenance protocols. Steel construction provides extended service life exceeding 100,000 connection cycles under normal industrial compressed air applications when operated within specified pressure and temperature limits. Replacement intervals typically range from 2-5 years depending on connection frequency, media cleanliness, and environmental exposure, with NBR seal replacement serving as the primary maintenance requirement before complete coupling replacement becomes necessary.
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