| Measuring range | 0 – 10 bar |
|---|---|
| Accuracy | ±0.5 % FS |
| Repeatability | ±0.1 % FS |
| Output signal | 4 – 20 mA / HART |
| Supply voltage | 12 – 36 V DC |
| Process connection | Ø 32 clamp |
| Enclosure protection | IP66 / IP69K IEC 60529 / ISO 20653 |
| Operating temperature | 0 – 130 °C |
What makes a pressure connection hygienic?
A hygienic connection leaves no internal cavity and no dead leg, and its surface finish matches the cleaning validation that was written for the circuit, so flow, cleaning fluid and steam all meet the same boundary the product touched.
Do flush diaphragms respond slower than ported transmitters?
A stiff flush diaphragm adds a small volume and a little mass in front of the sensor, which can soften very fast pressure steps, but in most vessel and pipe duties that lag stays well below the speed at which the process itself moves.
How should the diaphragm be handled during installation?
The sensing face is a welded metal membrane, not a part to be wiped, so installation keeps tools off it, checks that the gasket face is flat, confirms drain slope, and only then tightens the clamp to the fitting's own procedure.
Definition
A hygienic pressure transmitter senses pressure through a flush welded diaphragm that replaces the process port, leaving no crevice where product could stagnate.
The APH-700 answers the failure mode of ordinary transmitters in hygienic loops, where product bakes onto a port thread beyond the reach of cleaning; its diaphragm sits flush with the vessel wall.
Why a flush diaphragm changes the cleaning problem
A pressure port with a thread and a shoulder is a small cavity, and every clean-in-place pass only rinses across its mouth. Product driven into that cavity then cures, harbours growth, and slowly drags the reading away from truth. Replacing the port with a diaphragm welded into the wall removes the cavity altogether, so the cleaning fluid meets the same smooth boundary the product met, with no shadow a jet could miss. The weld and the surface finish are then part of the cleaning claim, and any rework has to hold the roughness the validation was written around.
Living through CIP and SIP cycles
Cleaning with hot alkaline and acid solutions, followed by steam sterilisation, puts the whole signal chain through temperature and chemistry it was never chosen for. The APH-700 keeps its electronics behind a sealed barrier and lets the process side be all metal, so the fill fluid, the diaphragm and the weld can follow the vessel’s own clean and sterilise recipe instead of a separate protocol for the instrument. After steam, watch whether zero returns to its archived baseline, because repeated thermal cycling shows up there first, and shorten inspection intervals while that trend is still young.
Zero shifts, and which one is real
Every hygienic transmitter drifts a little when its filling fluid meets a new temperature, so the first question at a suspicious reading is whether the movement belongs to the process or to the instrument. Static head, mounting height above the datum and product density all bend the number before the sensor itself is wrong. Establishing a clean zero with the transmitter vented at a known temperature turns those effects into a fixed offset the next crew can subtract. Keep that zero check on the post-clean checklist, archive the offset with the batch number, and schedule an offline verification whenever it crosses a warning line.
All figures on this page are illustrative sample values, not measured specifications.