The AirTAC Airtac 4V Solenoid Valves 4V31008BT is a genuine 5/2-way single solenoid (spring return) solenoid valve with 31008BT ports and an effective area of 28.0 mm² (Cv 1.65). It is an internally piloted spool valve that directs compressed air to double-acting cylinders and actuators.
The 4V310-08BT is the 1/4in NPT-port version of the AirTAC 4V300 body, built as a single-solenoid 5/2 directional valve for double-acting cylinders and pneumatic actuators. It switches one bore side to pressure while exhausting the other, and its 28.0 mm2 effective area (Cv 1.65) comfortably serves bores around Dia 50-80 mm. The coil runs on DC24V at just 3.0 W, and power reaches the spool through an integrated terminal box, so site wiring lands on screw terminals instead of flying leads. Response time is 0.05 s or below. Because this is a spring-return valve, the coil must stay energised to hold the working position; cut the DC24V supply and the internal spring drives the spool back, sending the cylinder to its rest stroke. The 310 g aluminium-alloy body carries IP65 (DIN40050) protection, a locking or non-locking manual override, and mounts on a base for a shared-supply manifold group.
| Model | Airtac 4V Solenoid Valves 4V31008BT |
|---|---|
| Series | 4V300 solenoid valve (spool type) |
| Valve type | 5/2-way |
| Function | Single solenoid (spring return) |
| Port size | 31008BT |
| Exhaust port | 31008BT |
| Effective area (Cv) | 28.0 mm² (Cv 1.65) |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Pilot type | Internal / external pilot |
| Operating pressure | 0.15 – 0.8 MPa |
| Proof pressure | 1.2 MPa |
| Max frequency | 4 cycle/sec |
| Response time | ≤ 0.05 s (activating) |
| Temperature | -20 to +70 °C |
| Body material | Aluminum alloy |
| Weight | 310 g |
Specifications follow the official AirTAC 4V series datasheet. Lubrication not required. Confirm coil voltage and thread (PT / NPT / G) against the product label before wiring.
| Effective area | 28.0 mm² |
|---|---|
| Flow coefficient | Cv 1.65 |
| Response time | ≤ 0.05 s |
| Coil power | AC 4.5 VA · DC24V 3.0 W · DC12V 2.5 W |
| Protection / insulation | IP65 (DIN40050), B-class |
| Voltage options | DC24V, DC12V, AC110V, AC220V |
| Manual override | Yes (locking / non-locking) |
Size the valve so effective area / Cv is not the bottleneck for your cylinder bore and speed. Undersized valves slow the actuator. Note 5/3 (center) versions have a smaller effective area than the 5/2 of the same body size.
| 4V | Solenoid valve, spool type, 4-series. |
|---|---|
| 3 | Body size (4V300) — sets port & flow. |
| 1 | Function: 1 = single 5/2, 2 = double 5/2, 3 = 5/3. |
| -31008BT | Port thread: M5 / 06=1/8" / 08=1/4" / 10=3/8" / 15=1/2". |
Related: 4V310 (single), 4V320 (double), 4V330C/E/P (5/3 center). Add the voltage suffix when ordering.
A Dia 63 mm swing clamp on a weld jig pairs well with Cv 1.65 flow: the clamp closes under coil power and springs open the moment the DC24V signal drops, a natural fail-safe posture for fixture work.
Pushing boxes off a takeaway conveyor with a Dia 63-80 mm cylinder uses the valve's 4 cycles per second ceiling and 0.05 s response, keeping push-off timing tight at line speed.
A Dia 80 mm gate cylinder on a warehouse sorter diverts totes between lanes; the NPT 1/4in ports match common US pipework and the terminal box simplifies control-panel wiring runs.
Size against the 4V300 class first: at Cv 1.65 this valve is the middle step, sitting above the 4V200 body (Cv 1.0) that better matches small bores up to roughly Dia 50 mm, and below the 4V400 body (Cv 2.82) you should choose once bores exceed about Dia 80 mm or cycle speed starts to sag. If you need the cylinder to stay put when power is lost, step from this spring-return 10 function to a 20 (double solenoid memory) or a 30C closed-center 5/3 valve, noting both move less air per cycle than a 5/2 in some designs. A single body on a foot-mounted base suits standalone machines; add a manifold base when several valves share one air supply. Ordering a replacement? Match all five points: body size 4V300, function 10 (single solenoid spring return), 1/4in port with NPT thread, DC24V coil, and terminal-box entry (not the I-suffix grommet).
Quick checklist
It directs compressed air to double-acting cylinders and actuators around Dia 50-80 mm bore. Core numbers in one place: effective area 28.0 mm2 (Cv 1.65), response time 0.05 s or below, working pressure 0.15-0.8 MPa with 1.2 MPa proof pressure, up to 4 cycles per second, DC24V coil at 3.0 W, and a 310 g body with 1/4in NPT ports.
The internal spring takes over: the spool returns to its rest position and the cylinder retracts (or extends, depending on plumbing) without any holding current. That is why this 10-function valve needs a constant electrical signal to stay in the working position. If you would rather the cylinder freeze where it is on power loss, choose a 20-function memory valve or a 30C closed-center valve instead, and add a pilot-operated check valve or mechanical brake wherever suspended loads must be held securely.
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