Alia ADM vs Pisonics PS7000 — Two Non-Nuclear Routes to Slurry Density
Both instruments replace a gamma density gauge, and both are spool pieces bolted into the line. That is where the similarity ends. The Alia ADM weighs the slurry; the PS7000 listens to it. The two methods fail in completely different ways, which is what should drive the choice.
Feature comparison
| Feature | Ultrasonic Slurry Density Meter | Alia Instruments ADM-S |
|---|---|---|
| Principle | Ultrasonic acoustic impedance, chirp pulse-echo | Accelerometer-based mass sensing (electromechanical) |
| Accuracy | ±1 % FS; the datasheet publishes ±1 % mass concentration | 0.5 % of full scale ¹ |
| Repeatability | Not published | ±0.1 % of full scale ¹ |
| Pipe size | DN50 – DN1000 (larger on request) | DN100 – DN500 per datasheet; 80–1300 mm per website ¹ |
| Process temperature | 0 – 80 °C standard; 120 °C high-temperature version to order | 0 – 60 °C ¹ |
| Ambient temperature | −30 – +60 °C | −25 – +50 °C ¹ |
| Process pressure | ≤ 1.6 MPa standard | 0 – 8 bar operating, 16 bar peak ¹ |
| Ingress protection | IP65 | IP66 ¹ |
| Hazardous area | Ex d IIC T6 Gb optional | Not published ² |
| Ambient vibration limit | None specified | Combined vibration in the Z excitation axis must stay below 10⁻⁶ (m/s²)²/Hz PSD across 20–120 Hz ¹ |
| Entrained air | Keeps measuring in bubbly slurry; outputs a 0–100 aeration index and a bubble flag | Not addressed in published material ² |
| Calibration | Multi-point field regression, up to 20 points, online, no shutdown; r² acceptance check from 3 points | Factory 3-point calibration; software taring on site ¹ |
| Communication | 2 × 4–20 mA (NAMUR NE43), RS485 Modbus-RTU, HART 5, Bluetooth 5.4 BLE, Profibus-DP optional, 4G cloud optional | Per Alia documentation ¹ |
| Mounting | Flanged spool piece, or weld-in boss on the existing pipe (Ø60 mm hole) | Flanged spool piece ¹ |
Competitor parameters cited from Alia Instruments ADM-S datasheet.
Takeaway
How the two measurements differ
The Alia ADM is a mechanical measurement. An actuator applies a known force to a movable measuring tube and a centre-mounted accelerometer records the response; from force and acceleration Alia derives the mass of the contents, and dividing by the known internal volume gives density. Accelerometers at each end compensate for external vibration. The measuring tube is a three-layer construction — metal outer, polyurethane intermediate, natural or EPDM rubber liner. (Manufacturer statement, aliainstruments.com/technology.)
The PS7000 is an acoustic measurement. A flush-mounted, wetted probe emits a chirp ultrasonic pulse and reads the echo from the probe/slurry interface. Acoustic impedance is density times sound velocity, so the interface reflection maps to slurry density.
The consequence that matters: the ADM integrates over the entire cross-section of the spool, so near-wall stratification does not bias it. The PS7000 reads a thin layer at the pipe wall, so it depends on that layer being representative — which is why our velocity and orientation requirements are strict. Conversely, the ADM is a dynamic mechanical system and Alia's own datasheet imposes a hard ambient-vibration limit; the PS7000 has no equivalent constraint.
Note on accuracy. On the full-scale metric the two are directly comparable, and Alia is the tighter figure: 0.5 % of full scale against our ±1 % FS. Our datasheet publishes ±1 % mass concentration, which is a third metric again and cannot be converted into either. Whichever way you cut it, ask both vendors to state accuracy against your range and your medium — a full-scale percentage grows in absolute terms as the range widens, so the comparison depends entirely on the range each instrument is set to.
Datasheet inconsistency worth knowing about. The Alia ADM-S datasheet lists range as 0.000 – 4.000 kg/m3 under a column headed Density ρ (ton/m3). Physically the values must be t/m³ (0–4000 kg/m³). This is an error in Alia's own document, not a specification difference.
About entrained air. The PS7000 is designed to keep measuring in bubbly slurry — that means a stable reading in the presence of gas, not a guarantee of accurate density at any gas fraction. The probe face must not be covered by a continuous gas phase: a gas film, a gas pocket or an empty pipe stops the measurement rather than biasing it. The entrained-air index exists so the control room can see which of those two situations it is in.
About the Ex rating. The PS7000 datasheet states Ex d IIC T6 Gb (option, to be specified when ordering) and does not name a certification body. Please confirm the certification scheme required in your target market with us before treating this as equivalent to an ATEX or IECEx certificate.
When to choose the Alia ADM
- Published accuracy on the full-scale metric is your deciding number. Alia states 0.5 % of full scale; we state ±1 % FS. On that comparison Alia wins, and we are not going to argue otherwise.
- The line vibrates less than the meter needs and stratification is your main worry. Full-cross-section mass sensing is genuinely immune to near-wall effects; an interface method is not.
- A factory calibration you can put in a document pack is a procurement requirement. Alia states it calibrates against an ISO 17025-traceable reference and ISO 17034 density standards, and that field work is limited to offset compensation.
- The application is a general-purpose area and you have no hazardous-area requirement.
When to choose the PS7000
- The area is classified. The PS7000 offers an Ex d IIC T6 Gb option; Alia publishes no explosion-protection rating.
- Process temperature is above 60 °C. Alia's datasheet stops at 60 °C; the PS7000 covers 0–80 °C as standard and 120 °C as a high-temperature version to order.
- The pipe is next to pumps, screens or a mill. Alia's datasheet sets a specific ambient-vibration ceiling. Acoustic impedance measurement carries no such limit.
- The line carries entrained air and you need to know when. The PS7000 reports it as a number alongside the reading.
- You cannot cut the pipe. The PS7000 offers a weld-in boss option on the existing line — a Ø60 mm hole — while the ADM is a spool piece.
- The pipe falls outside DN100–DN500, which is the range in the ADM-S datasheet. Note that Alia's website cites a wider 80–1300 mm range — ask Alia which figure applies to the model you are quoted.
FAQ
Is the Alia ADM ultrasonic?
No. Despite frequently appearing in searches for ultrasonic slurry density meters, the ADM is an electromechanical mass measurement using an actuator and accelerometers. Alia's own technology page describes the method in these terms.
Which one handles entrained air better?
Alia's published material states the ADM can measure media containing gases but does not quantify the resulting error. The PS7000 is designed to continue measuring in bubbly slurry and outputs an aeration index so the operator can judge the reading. Neither instrument gives a correct liquid-phase density when the line is heavily aerated — that is a process problem, not an instrument problem.
Can either be installed without cutting the pipe?
The PS7000 offers a weld-in boss variant that requires only a Ø60 mm hole in the existing line. The ADM is supplied as a flanged spool piece.
Sources
- Manufacturer statement — Alia ADM-S datasheet, edition September 2020. Please verify against current documentation before relying on it.
- Not published on aliainstruments.com or in the datasheet as of August 2026.
Competitor facts verified August 2026, all from the manufacturers' own websites, official PDF datasheets or officially hosted documents. PS7000 figures are from PS7000_技术规格书_中文.pdf Rev. A · 2026-08 (PS7000-DS-ZH-A). Manufacturers revise published data without notice — please re-check before relying on any figure here.
Talk to us
Pisonics — Xi'an Pisonics Information Technology Co., Ltd.
15B016, Block A, Olympic Building, Chang'an North Road,
Beilin District, Xi'an, Shaanxi 710061, China
+86 159 0293 2017 | info@pisonics.com | www.pisonics.com
Send us pipe size, orientation, slurry velocity, particle size distribution and whether the line carries entrained air — we will tell you whether an acoustic measurement holds up on your line, or which principle fits better.