Where it fits
A standard straight-through diaphragm valve sits mid-run, with pipe on both sides. The two valves in this series deal with two awkward spots in a line: the branch point and the bottom of a vessel. Build either of those from a tee fitting, a spool and a straight valve, and the short spool between the tee and the valve becomes a dead leg the flow never reaches — chemical sits in it, cleaning never quite flushes it out, and it carries over into the next batch at changeover.
The tee valve builds the valve into the tee itself, in DN25 × DN40 or DN25 × DN25 (run × branch). The tank-bottom valve mounts on the outlet at the bottom of a vessel, DN50, and exists to keep the dead leg between vessel and valve as short as possible. Both have a high-purity PFA wetted surface and serve chemical delivery in semiconductor chemical distribution systems (CDS), ultrapure fluid lines in wet processing, display and solar wet-process lines, and pharmaceutical lines designed to the BPE standard.
Key characteristics
- Valve and branch in one body: the tee valve does away with the spool between tee and valve, so the dead leg at the branch shrinks with it — the main difference from a straight valve plus a tee fitting.
- PTFE / EPDM composite diaphragm: the PTFE face meets the fluid while the EPDM backing provides resilience. The diaphragm also seals the fluid off from the actuator above, so the stem and threads never touch it.
- PFA inside, metal outside: the flow path is lined with high-purity PFA, so every wetted surface is fluoropolymer, while the 316L stainless outer body (316L stainless / PES on the tee valve) carries the piping loads. The manual actuator is cast 316L stainless.
- Operating envelope: resistant to acids, alkalis, chemicals and steam; -30 to +150 °C; vacuum to 1.0 MPa (at 20 °C). The PFA resin can be specified to suit the cleanliness requirement — an ultra-high-purity grade from a leading international brand, or a cost-effective high-purity grade — and material certificates are available.
Choosing between options
Start from where the valve goes, then pick the configuration:
| Location | Configuration | Size & connection |
|---|---|---|
| Branch point (take-off, split or return line) | Tee (JY-VLC5T) | DN25 × DN40, DN25 × DN25; Tri-Clamp |
| Vessel bottom drain / discharge | Tank-bottom (JY-VLC5B) | DN50; Tri-Clamp or flange |
| Ordinary straight run | Straight Tri-Clamp diaphragm valve | PFA-lined Tri-Clamp diaphragm valve (pneumatic versions available) |
Tee sizes read run × branch: DN25 × DN40 means a DN25 run with a DN40 branch. Check the direction against the piping drawing before ordering — swap run and branch and the valve will not fit. This series is manual only. Where automation is needed, straight runs can use the Tri-Clamp diaphragm valve with normally open or normally closed pneumatic actuation; for automated tee or tank-bottom duty, check with our sales team first.
Operation & change-out
A Tri-Clamp joint seals on the gasket and the clamp. Make sure the gasket matches the ferrule size and sits centred, then tighten the clamp evenly — overtightening squeezes the gasket into the bore and creates a new crevice. If you choose the flanged tank-bottom valve, the flange must match the nozzle on the vessel bottom, so include that with your enquiry.
The diaphragm is the main wear part in this type of valve. Check regularly for weeping and for a handwheel that turns stiffly or no longer shuts off fully. Drain and flush the valve before changing the diaphragm so nobody is exposed to residual chemical. The higher the temperature, the less pressure the PFA lining and diaphragm can take, so check hot, high-pressure duty with our sales team first.