PIOX S ultrasonic density meter determines the concentration and density by means of clamp-on ultrasonic transducers mounted on the outside of the pipe. The non-invasive technology found in this inline density meter is the system of choice when substances and processes place highest demands on safety and reliability.

The sound velocity sensor PIOX S measures in real time the speed of sound through liquids. In binary liquids such as acids or sodas, the acoustic velocity is in a fixed proportion to concentration and density. PIOX S measures the sound velocity, thereby measuring the inline density and concentration of the medium.

PIOX S can be used to determine the concentration of high purity sulfuric acid, hydrofluoric acid, nitric acid or even ammonia gas used in fertilizer plants. Worries about the ultrasonic density sensor’s chemical compatibility, contamination and sealing are a thing of the past.

With the clamp-on ultrasonic density measurement technology, retrofitting of existing installations is very easy and can be done without cutting into the pipe and without any process interruption.


  • Fits all pipe sizes from ½” to 8”
  • For all pipe materials – glass, steel, plastic and more
  • For temperatures up to 400 °C
  • For almost all acids, caustics and a wide range of other toxic liquids
  • For ATEX, IECEX and FM areas
  • No shut down for installation
  • Maintenance free


Technical Facts

Measuring quantities
Sound velocity
concentration g/l, mass and vol.%,
additional quantities programmable
Measurement range
1000-2500 m/s (0-100 w%)*
Measurement accuracy
Instrument is field calibrated
0,1 w%* (0,5m/s)
Diagnostic values
Signal quality
Media temperature
-60 °C ... +400 °C**
Fluid pressure
3000 bar
Degree of protection
Ultrasonic Transducers: IP67, ATEX (IECEx) zone 0,/1
Transmitter S721: aluminum or stainless-steel enclosure, IP66, ATEX (IECEx) zone 2
Wetted parts, materials
Housing Material
Stainless Steel 304 (1.4301)
Process connection
Clamped onto the pipe with Variofix system
Cleaning systems
Not required
Additional Information
* For most waterbased solutions and common working point
** additional wave injector required