In short: the 3/4" SANITRX HPX® (reference CDC 3/4") is the small-diameter version of the SANITRX sanitary discs. It makes it possible to place a reverse-acting relief point on 3/4" hygienic lines, where the 1 to 3 inch models do not fit.
How it works
It is a semicircular, scored, reverse-acting dome: pressure acts on the convex face and, on reaching the burst value, the dome reverses and opens along the score line without releasing fragments. The principle is identical to that of its larger siblings; what changes is the scale.
Reducing the diameter is not trivial. On a small disc, the area on which the pressure acts is smaller, so the force available to reverse the dome is also smaller, and manufacturing tolerances (thickness, score depth) weigh more heavily on the result. That is why a 3/4" disc is designed and qualified as its own model, not as a cut-down version of the 1-inch one. Another consequence of scale is relief capacity: the flow area is limited, so you must verify that the disc can discharge the flow rate of the overpressure scenario.
It mounts between standard 3/4" Tri-Clamp® fittings, which allows it to be integrated into CIP/SIP lines without special fittings. According to the manufacturer, the materials comply with ASME BPE, USP Class VI and 3-A, the interior surface is polished (on the order of 20 µin Ra) and each unit is delivered in sanitary packaging suitable for cleanrooms, which facilitates validation in GMP environments.
When it makes sense (and when it does not)
- Suitable for small equipment and lines: laboratory or pilot tanks, sampling lines, dosing skids, filters or small hygienic vessels.
- Suitable when space is limited and you do not want to enlarge the connection just to fit the disc.
- Recommended for processes with traceability and validation requirements.
- Not suitable if the relief calculation requires more area than 3/4" offers; in that case you must move up to a larger-diameter SANITRX.
- Caution: a small, thin disc is easily damaged during handling; it is advisable to take it out of the packaging just before installing it.
Data to specify it
- Burst pressure and temperature, including sterilization conditions.
- Required relief flow rate, to confirm that 3/4" is sufficient.
- Operating pressure and presence of cycling.
- Type of sanitary clamp and gasket to be used.
- Material and finish documentation required by the quality system.
| Characteristic | According to the manufacturer |
|---|---|
| Reference | CDC 3/4" |
| Type | Semicircular, grooved, reverse-acting, non-fragmenting |
| Connection | 3/4" Tri-Clamp® |
| Declared standards | ASME BPE, USP Class VI, 3-A |
| Gasket | Sanitary, suitable for clean rooms |
To learn more: Sanitary rupture discs and Relief area calculation according to API 520.
Descriptive sheet for educational purposes. For availability and a quote for this model, consult P&V Control Devices.