KF vacuum ball valve
A three-piece 316 vacuum ball valve with KF clamp flanges — NW16, NW25, NW40, NW50, or ISO-K 80. The body opens for cleaning, the bore is full port, and it comes with a hand lever or an ISO 5211 pad for an actuator.
Built to hold, built to last.
The body comes apart. Undo the four through-bolts and the centre section lifts out with the ball and seats still on it — so a valve that has been sitting in a dirty foreline can be cleaned and re-seated instead of scrapped. On a two-piece or one-piece body that is not an option.
Body and ball are A351 CF8M — cast 316 — with PTFE seats and gaskets. Six sizes are made: 1/2″ (NW16), 1″ (NW25), 1-1/4″ (NW40), 1-1/2″ (NW50), 2″ (NW50) and 2-1/2″ (ISO-K, ISO80). Full port throughout, so conductance is not choked at the valve.
Two builds share the same body. V-3A is the manual one, a quarter-turn lever. V-3AM has the lever removed and an ISO 5211 pad on top, plus a reinforced Viton O-ring on the stem — order that one when an actuator goes on the valve. It is shown here with a rack-and-pinion pneumatic actuator fitted.
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V-3A
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V-3AM
- Body
- A351 CF8M (cast 316)
- A351 CF8M (cast 316)
- Size range
- 1/2″ – 2-1/2″
- 1/2″ – 2-1/2″
- Connection
- KF NW16 · NW25 · NW40 · NW50 · ISO-K 80
- KF NW16 · NW25 · NW40 · NW50 · ISO-K 80
- Seat
- PTFE
- PTFE
- Temperature
- −20°C to 180°C
- −20°C to 180°C
- Port
- Full port
- Full port
- Operation
- Quarter-turn lever
- ISO 5211 direct-mount pad
Where it gets used
Every valve leak tested.
Each unit is checked for leakage before shipment.
What is the difference between V-3A and V-3AM?
Same three-piece body. V-3A is manual with a quarter-turn lever. V-3AM replaces the lever with an ISO 5211 mounting pad and adds a reinforced Viton O-ring on the stem, so an actuator can be bolted straight on.
Which flange sizes do you make?
KF clamp flanges in NW16, NW25, NW40 and NW50, and ISO-K in ISO80. Valve sizes run 1/2″ to 2-1/2″. Tell us the flange and we will confirm the build.
Why a three-piece body for vacuum?
Because it opens. Seats and gaskets are wear parts; on a three-piece body you undo the through-bolts, clean or re-seat the valve and put it back. A one-piece or two-piece valve in the same duty gets replaced.
Is this the same as your ISO-K vacuum ball valve?
No. That one is a two-piece body in ISO-K DN80 and DN100 only. This is the three-piece body, KF NW16–NW50 plus ISO-K 80, and it is the one that opens for cleaning.
Can I add an actuator later?
Order the V-3AM. It has the ISO 5211 pad already on the body, so an actuator bolts on without a bracket.
What vacuum level is it for?
Rough and medium vacuum isolation. For UHV chambers you would move to metal-sealed valves — a different class of hardware.
