Frequently asked questions

An industrial online density meter is an instrument that is directly installed on process pipelines or storage tanks and continuously outputs the density (or concentration) of the medium in real time. Its main differences from laboratory density meters (such as pycnometers and vibrating-tube benchtop models) lie in three aspects:

1. Online density meters perform continuous measurements without the need for sampling;
2. They output 4–20 mA / Modbus signals, allowing direct connection to DCS/PLC systems;
3. Their protection and explosion-proof ratings, as well as their wetted materials, are all designed in accordance with industrial-site standards.

Pisonics offers online density meters based on various principles, including ultrasonic, tuning fork, differential pressure, Coriolis, optical and microwave technologies, covering all operating conditions—from slurries to clean liquids.

Short answer: For high solids content and bubbly processes, choose an acoustic impedance density meter (PS7000).

• Acoustic impedance meters excel at resisting fouling and bubbles, with a typical range of 0.5–3.0 g/cm³; their simple mechanical design keeps maintenance costs low. However, for highly abrasive slurries, a wear-resistant tuning fork is recommended.
• Tuning fork concentration meters are not wear-resistant but susceptible to bubbles; they are relatively expensive, have specific pipe‑diameter requirements, and are easily affected by gas entrainment.

In mining applications such as overflow/slurry from ore beneficiation—where solids content is 30–60% and the slurry is highly abrasive—acoustic impedance meters are by far the most common choice; in cleaner conditions like the downstream section of chemical reactor vessels, tuning fork meters offer a clear advantage.

Selection primarily hinges on four key factors:

1. Medium characteristics—slurry solids content, presence of bubbles, scaling propensity, and corrosiveness;
2. Installation conditions—whether tapping and hot work are permitted, available straight-run pipe lengths, and pipe diameter;
3. Accuracy requirements—trade metering calls for ±0.0005 g/cm³ accuracy (Coriolis), while process monitoring can suffice with ±0.005 g/cm³;
4. Compliance requirements—whether radioactive sources are to be avoided.

Common applications include: bubbly slurries → Pisonics PS7000 ultrasonic acoustic impedance; no‑tapping allowed → Pisonics PS7010 external‑mount; high‑accuracy pure liquids → Pisonics PS7200 Coriolis; severe scaling → Pisonics PS7400 tuning fork; large‑diameter main lines → Pisonics PS7300 differential pressure; waterborne suspensions → Pisonics PS7600 microwave; ultra‑high‑precision optics → Pisonics PS7100 spectroscopy / PS7110 refractometry. For details, refer to the “How to Select a Density Meter” guide.

Accuracy is deviation from the true value — ±0.002 g/cm³ means the reading may run 0.002 above or below actual density. Repeatability is the spread between successive measurements on identical material — ±0.0005 g/cm³ means the trace won't wander beyond that band. For selection: custody transfer and quantitative batching demand accuracy; trend monitoring, process control, and alarm thresholds depend on repeatability. Most sites need both, but repeatability has the bigger day-to-day impact — a noisy reading floods the DCS with false alarms even when long-term accuracy is fine.

Pisonics offers four types of non-nuclear online density meters that can replace traditional instruments using Cs-137/Co-60 radioactive sources:

1. PS7000 ultrasonic acoustic impedance—suitable for bubbly slurry and highly abrasive slurries;
2. PS7010 ultrasonic acoustic attenuation—ideal for conditions where opening the vessel is not permitted, with an external mounting that requires no hot work;
3. PS7400 tuning fork—appropriate for scaling-prone applications and chemical slurries;
4. PS7300 differential pressure—designed for large‑diameter main pipelines (DN200+).

If the project genuinely requires a nuclear principle (such as dense-medium coal washing), a gamma gauge with an exempt-activity Na-22 source (<1,000 KBq) needs no radioactive-source or transport permit. We no longer supply that class of instrument; it is noted here for completeness.

Pisonics’ mainstream density meters all offer explosion-proof versions:

1. The ultrasonic series (PS7000, PS7010, PS7020) can be optionally equipped with ExdⅡCT6Gb;
2. The tuning fork model PS7400 can be optionally equipped with Ex d ⅡC T6 Gb;
3. The Coriolis model PS7200 can be optionally equipped with Ex d ⅡB T6 Gb;
4. The differential pressure model PS7300 is available in intrinsically safe ExiaIICT6 and flameproof ExdIIBT4 configurations;
5. The spectral model PS7100 can be optionally equipped with Ex db ib IIC T6 Gb;
6. The refractive-index model PS7110 is intrinsically safe: Ex ia IIC T6 Ga;
7. The microwave model PS7600 can be custom‑configured for explosion protection.

All explosion‑proof models have passed CNEX explosion‑proof certification. When placing an order, please specify the applicable hazardous area classification (Zone 0/1/2) and the temperature class.

The standard model delivery time is typically 2–4 weeks.

Customized models (featuring special wetted materials such as 2205 duplex stainless steel, Hastelloy, or titanium; non-standard measurement ranges; special linings; explosion-proof variants; sanitary process connections, etc.) have a delivery time of 4–10 weeks.

Bulk orders or urgent projects can be expedited.

All series support process customization: probe length, process connections (flanges to ANSI, DIN, and JIS standards, clamps, and threads), cable length, display language, and communication protocols (Modbus, HART, Profibus, and 4–20 mA).

Before placing an order, we dispatch an engineer to verify the operating conditions and provide a written selection proposal.

In industrial environments, under normal operating conditions, it is recommended to perform zero/span verification and calibration every 12 to 18 months. The specific frequency depends on the process conditions: for clean, stable media (such as finished oil or syrup), the interval can be extended to 24 months; for media containing abrasive particles or at elevated temperatures, calibration at 6 to 12-month intervals is advised.

Calibration methods:

1. Manual sampling and laboratory analysis, followed by comparison with the instrument readings and adjustment of the zero/span offsets;
2. In‑place calibration using a reference solution (e.g., a brine solution of known concentration);
3. Remote support—access the Pisonics remote diagnostic system via RS‑485 or 4G, where engineers can analyze the data online and provide guidance for adjustments.

The Pisonics headquarters offers factory‑level traceable calibration using temperature‑controlled laboratory equipment.

Work through process first, installation second, instrument last — six steps cover most cases:

1. Confirm the fluctuation is real — take 3 to 5 manual samples in parallel; if lab values swing too, the process itself is moving (feed changes, agitation, crystallization), not the meter;
2. Check for bubbles — aeration, pump suction vacuum and cascading inflows all shake the reading. Bubble-sensitive principles (tuning fork, DP, single-frequency ultrasonic) suffer most; gassy media are better served by acoustic impedance with Chirp processing (PS7000);
3. Check full-pipe condition and mounting location — a partially filled pipe, phase separation, or mounting too close to elbows and valves (less than 5D upstream / 2D downstream) introduces turbulence noise;
4. Check fouling and wear — scale buildup shows as slow drift followed by jumps; abrasive slurry wears contact sensors. Inspect visually through the access port;
5. Check electrical — 4-20 mA loop load (max 500 ohm), ground loops, VFD interference; on remote versions ground the cable shield at one end only;
6. Check settings — damping or filter time set too short amplifies normal process noise; verify calibration factors against manual samples if drift is suspected.

If readings are still abnormal after all six steps, connect via RS485 / 4G to the Pisonics remote diagnostic system and an engineer will review the raw signal online.

Manual sampling comparison is the gold standard — done wrong, it blames a healthy instrument. The correct procedure:

1. Sample next to the meter — within 1 to 2 m downstream of the measuring point; farther away, real concentration gradients get mistaken for meter error;
2. Synchronize records — note the meter reading at the moment of sampling (or use the built-in data log timestamps); slurry concentration shifts within minutes;
3. Take 3 to 5 samples — a single point has no statistical meaning; compare averages and watch the spread;
4. Mind the temperature — lab temperature differs from process temperature; convert density to the same temperature before comparing (the meter reading is usually already temperature compensated);
5. Judge correctly — deviation within instrument accuracy (for example 1% FS) plus sampling error is normal; a systematic offset (same direction, stable size) needs only a zero/span adjustment, not a factory return.

Reference: at a potash plant in Qinghai, two weeks of daily sampling against a PS7000 held deviations at 0.5% to 0.8%, including through concentration peaks.

Supported; products have been exported to countries including Southeast Asia (Vietnam, Indonesia, Malaysia), the Middle East (Saudi Arabia, UAE), Africa (South Africa, Zambia), South America (Chile, Peru), and the Commonwealth of Independent States (Russia, Kazakhstan).

Major international certifications: CE certification (European Union), ATEX/IECEx explosion-proof certification (for select models), and RoHS certification.

Supplied with EN 10204 3.1 material certificates, an English-language user manual, installation and commissioning videos, and remote technical support (including multilingual engineers who speak Vietnamese, Spanish, Russian, and other languages).

There is no list price for inline density meters — the same model can vary 2 to 3 times in price depending on configuration. The final figure is driven by six factors:

1. Measuring principle — tuning fork and differential pressure designs are the most economical; ultrasonic and microwave sit mid-range; Coriolis and spectroscopic (with modeling) are positioned higher. Nuclear gauges add ongoing compliance costs on top of the instrument itself.
2. Wetted materials — 316L is the baseline; corrosive media require 2205 duplex, Hastelloy C-276, titanium or full PTFE lining, and abrasive slurries call for ceramic sensor faces. Materials are the single biggest price lever.
3. Explosion proofing and certification — Ex d IIC T6 Gb housings, sanitary builds (Tri-Clamp, mirror polish) and CE / ATEX export certification all add cost.
4. Pipe size and process connection — DN50 to DN1000 is standard; larger bores and non-standard flanges are custom work.
5. Mounting and options — integral vs remote electronics (signal up to 500 m), 4G telemetry, remote displays.
6. Customization and modeling — spectroscopic multi-component analysis needs an MLR model built from your medium samples (2 to 4 weeks); non-standard ranges and insertion lengths are quoted per case.

The fastest route to a real number: send your process datasheet (medium, concentration range, temperature, pipe size, hazardous-area class) to a Pisonics engineer — a written model selection and quotation comes back within 2 working days.

Both are ultrasonic-based, but their underlying physical principles and applicable operating conditions differ significantly:

The PS7000 employs the acoustic impedance method—using a single probe for both transmission and reception to measure the reflection characteristics of ultrasonic waves at the interface. Its advantages include strong resistance to bubble interference (thanks to the Chirp broadband algorithm) and broad media adaptability (even for solid–liquid two-phase slurries); installation is flanged direct insertion, requiring a hole to be drilled.

The PS7010 uses the acoustic attenuation method—employing a through-beam configuration with one transmitting and one receiving probe to measure the energy attenuation after wave penetration. Its advantages are non-invasive external mounting without drilling (in certain applications), a simple and reliable principle, and high accuracy for clean slurries; its disadvantages are sensitivity to bubbles and stringent requirements for pipe wall thickness in external mounting.

A simple guideline: if bubbles are present → choose the PS7000; if no drilling is permitted → choose the PS7010; for standard cases, either model can be selected based on specific needs.

View product · Ultrasonic Slurry Density Meter →

View product · Ultrasonic Slurry Density Meter →

View product · Ultrasonic Slurry Density Meter →

The PS7000 is an acoustic-impedance ultrasonic density meter with no radioactive source whatsoever. No radiation license is required. It uses only piezoelectric transducers to send and receive ultrasonic signals — the same physical principle as medical and NDT ultrasound.

If you're currently using a Cs-137 / Co-60 source-based meter and want to remove the regulatory burden, PS7000 is a practical alternative; it installs differently, so check straight run and spool fit before a retrofit. A gamma gauge with an exempt-activity Na-22 source (< 1000 KBq) also needs no radiation license, but we no longer supply that class of instrument.

View product · Ultrasonic Slurry Density Meter →

Because an ultrasonic density meter reads acoustic impedance, Z = ρ × c, not density, and dichloromethane happens to be dense and acoustically slow, so the two factors cancel. At 20 °C water is 1.48 MRayl and DCM about 1.45 MRayl, and between roughly 15 and 20 °C they coincide — which is where most plants separate. Inferred against water's velocity, DCM reads about 0.98 g/cm³: lighter than water, the wrong way round.

The same pair differs by 390 m/s in sound velocity (1482 against 1090 m/s, about 26 %), with opposite temperature coefficients, so warming widens the gap. That is why this duty takes the sound-velocity model (PS7021) rather than the impedance one (PS7000). DP and Coriolis meters do read true density and can separate the pair in principle, but they cannot keep up with a draining batch.

View product · Inline Ultrasonic Phase Separation Detector →

View product · Microwave concentration/density meter →

View product · Ultrasonic Slurry Density Meter →

The rag layer is a third state, not a grey zone between two. Two quantities catch it.

First, velocity: a dispersion falls between the two bands (Wood's equation, first order, puts 30 vol% DCM near 1338 m/s and 50 vol% near 1256 m/s), and anything outside the clear-phase bands is not reported as a clear phase. Second, and more decisively, amplitude: droplet scattering weakens the echo, and 6 dB below the clear-phase baseline is reported as emulsion / not-decidable by default.

The interlock direction is fixed: on emulsion the instrument holds the valve and raises an alarm rather than switching. It will stop and wait for an operator before it lets a rag layer pass as either phase. The emulsion itself is a separation problem; what the instrument can do is refuse to wave it through.

View product · Inline Ultrasonic Phase Separation Detector →

Yes. DN32 is one of the standard bores (DN25 / DN32 / DN50). The lined build is a steel shell with a PTFE/PFA liner and sapphire windows that pass through the liner and wet the process.

Measuring through the liner is not an option: PTFE is 2.97 MRayl and strongly attenuating, and the bond between liner and shell changes with temperature and permeation — that turns a fixed acoustic path into a drifting one.

Two ordinary lined-pipe rules also apply. Wetted seals are PTFE or FFKM; ordinary FKM rates only fair against methylene chloride. And the shell's vent holes must stay clear — chlorinated solvents permeate fluoropolymer liners slowly, and trapped permeate lifts the liner off the wall.

View product · Inline Ultrasonic Phase Separation Detector →

Choose by whether the premise holds; each method rests on one.

Conductivity assumes the aqueous phase conducts, the organic does not, and an electrode may wet the process. Where that holds it is the cheapest answer. Pure-water washes, wet organics and lined pipe that is awkward to tap all soften it.

Photoelectric / sight glass assumes an optical difference. Turbidity- and colour-based units fail outright on dichloromethane and water — both are clear and colourless — while a refractive-index unit does work (1.424 against 1.333). Both share one weakness: a fouled window.

Sound velocity (PS7021) rests on two conditions only: the phases differ by at least 30 m/s, and the pipe runs full. It is independent of colour, turbidity, conductivity and density, which is why it holds where both phases are clear, both are non-conducting, or the aqueous conductivity moves. The price is a two-phase calibration on site, repeated at product changeover — five minutes, but somebody has to do it.

The item-by-item comparison is here.

View product · Inline Ultrasonic Phase Separation Detector →

No shutdown. Calibration needs two velocity bands, and both samples come out of a normal batch: one while the light phase is running steady, one while the heavy phase is, 200 mL or more each. The instrument reads them itself — nothing goes to a lab. It usually fits inside one batch.

Three cautions: sample at process temperature (velocity is temperature sensitive, organics run −3 to −4 m/s per °C); draw the sample near the measuring point; and take the aqueous phase at its real salinity — clean water is not a substitute.

What you end up with is a velocity-versus-temperature table for both phases, delivered with the instrument. If the process temperature changes later, the thresholds shift along that table without a service visit.

View product · Inline Ultrasonic Phase Separation Detector →

Three volt-free contacts carry heavy, emulsion and light. The usual wiring: heavy closed → diverter to the heavy receiver; light closed → light receiver; emulsion closed → hold the current position and alarm for an operator to confirm.

The failure direction is the first thing to settle. Gas, flashing and window film all push the instrument toward not-decidable rather than toward the other phase, so making not-decidable mean stay put runs with the grain of the disturbances. Defaulting it to either phase turns every disturbance into a carry-over incident.

Keep the manual mode and the existing sight glass: the instrument supplies the judgement, not the valve. 4-20 mA trends velocity in the DCS; RS485 exposes phase, velocity, amplitude and temperature for the batch record.

View product · Inline Ultrasonic Phase Separation Detector →

The output is a phase decision, not a concentration you can compare against a titration, so acceptance looks different from a concentration meter's. Three workable tests:

1. Timing against the operator. Run a number of batches and align the instrument's switch instant with the operator's call at the sight glass. The site sets the tolerance; what usually matters is whether the instrument is ever late, since late means carry-over.

2. Sampling around the cut. Draw a sample either side of the instrument's switch instant and check that carry-over sits inside process limits.

3. The velocity itself. Measured band values should match the calibration table, and batch-to-batch drift in one phase should stay within the repeatability seen at calibration (±0.2 m/s). This is the test that separates "the instrument drifted" from "the material changed".

View product · Inline Ultrasonic Phase Separation Detector →

No — those are different instruments. PS7021 is an inline spool and knows only what is crossing its acoustic path right now: heavy, emulsion or light.

Interface height in a tank or settler belongs to an interface level instrument (magnetostrictive, radar, ultrasonic level, capacitance), mounted on the vessel rather than in the line. Rag layer thickness is the same question.

There is a useful indirect answer, though: time the instrument spends in the emulsion state during a drain, multiplied by flow, gives the volume of rag in that batch. It is not an interface height, but as a trend for how well the break worked or whether settling time is enough, it is often the more direct number.

View product · Inline Ultrasonic Phase Separation Detector →

No straight run is required. The path length is fixed by the spool and the discriminators are velocity and amplitude, which do not care about the flow profile — unlike DP, vortex or magnetic meters, which live on it.

The position still matters, but for a different reason: phase and gas. Pump discharges, the downstream side of control valves and other throttling points generate gas or flashing continuously, which holds the amplitude down and degrades three-state discrimination. Mount upstream of them, or further downstream where the flow has settled.

Three other rules: a full line is not negotiable; on horizontal runs put the path across the horizontal (3 and 9 o'clock), away from gas at the top and solids at the bottom; and keep the measuring point close to the diverter, because that hold-up is the mixed volume every batch pays.

View product · Inline Ultrasonic Phase Separation Detector →

Temperature: −20 to +80 °C standard, −20 to +120 °C for the high-temperature variant. Heat actually helps the discrimination: organic velocity falls with temperature while water rises below 74 °C, so the bands spread. Edible oil washing at 80-90 °C is the textbook case.

Sanitary: the standard spool is industrial and flanged. Tri-clamp, polished bore and drainable geometry are a custom build with their own lead time and price — say so at selection rather than assuming the standard spool can enter a sanitary zone.

CIP: the sapphire window is dense and smooth, so hot caustic, hot water or solvent all clean it in place. Compare the amplitude baseline before and after and you know whether the clean worked — far easier than scheduled teardown.

View product · Inline Ultrasonic Phase Separation Detector →

Yes, with one distinction.

The PS7000 employs a linear frequency-modulated (Chirp) acoustic impedance algorithm: after transmitting a broadband ultrasonic pulse, the host unit analyzes the echo in the frequency domain, and multiple-reflection interference from fine, dispersed bubbles is identified and suppressed. That is the main difference from conventional single-frequency reflective meters. The meter also outputs a 0–100 gas index and a bubble flag, so the DCS can tell a real change in concentration from a bubble-driven high reading.

Heavy free gas (pump suction drawing air, a falling stream entraining it, a point directly above an aeration header) or a continuous gas film over the sensor face pushes the reading high or stops it altogether. That is a limit of acoustic measurement: it is avoided by where the sensor goes, not corrected in calibration.

At the gypsum discharge line of an absorption tower in a thermal power plant in Inner Mongolia (under conditions of continuous air oxidation that generate dense bubbles), the PS7000 has been operating stably for several years after replacing the original tuning fork concentration meter.

View product · Ultrasonic Slurry Density Meter →

It depends on the load. A light suspension does not move the velocity reading but scatters sound and lowers the echo amplitude — and amplitude is what catches the rag layer, so with heavy solids three-state discrimination degrades to two: light and heavy still separate, emulsion and "solids present" no longer do.

In practice: put the point after settling, filtration or a steady pump; at commissioning re-baseline the amplitude against the real solids-bearing fluid rather than against clear liquid; and if solids content is itself the quantity you want, that is another instrument — PS7000 and the acoustic-impedance method.

Crystals add one more wrinkle: they grow a film on the window. The film shows in the amplitude baseline first, which makes that baseline a useful clean-me reminder.

View product · Inline Ultrasonic Phase Separation Detector →

PS7000 installs in one of two ways, and both have the same process requirements:

1. Spool type: a flanged measuring spool (ANSI / DIN / JIS) goes into the line, with the sensor face made flush with the bore at the factory. Weld-in type: a Ø60 mm hole and a welded boss on the existing pipe, with no cut-out, which suits large existing mains;
2. Straight run ≥ 10D upstream and ≥ 5D downstream (5D / 3D minimum where space is tight), away from pump discharges, valves and bends;
3. Prefer a vertical run with upward flow. On a full horizontal line, mount at mid-height on the side of the pipe, clear of settled solids at the invert and air at the crown;
4. The pipe need not run full, but the sensor face must stay submerged under every operating condition — on a part-full line, mount on the lower half of the side wall, below the lowest operating level and above any deposit at the invert;
5. Keep velocity above the deposition velocity and preferably no more than 5 m/s. Readings taken while the line stands after a pump stop do not represent the process; gate them with the pump-running signal in the DCS;
6. Line sizes DN50 to DN1000 (larger on request). The window is sapphire; for heavy abrasion choose 316L with special ceramics or a 2205 duplex probe, and for strong corrosion a PTFE lining.

For how to choose the angle and level on a part-full line, see coal slurry thickener feed and underflow. If the line cannot be drilled, hot-worked or shut down, select the PS7010 clamp-on meter instead.

View product · Ultrasonic Slurry Density Meter →

The floor is 30 m/s at working temperature. Common organic-against-water pairs are far above it: carbon tetrachloride is 572 m/s from water, dichloromethane 428, ethyl acetate 413, toluene 170, m-xylene 155 (handbook values at 25 °C). For those the gap is never the constraint.

Three cases do need arithmetic first: oil against oil (diesel and kerosene are 74 m/s apart), oil against water at ambient (edible oil and water, about 66), and formulated fluids — peroxide working solution, SX organic, a demulsified waste oil.

How to estimate: take handbook values at 25 °C, carry both to working temperature with their coefficients (organics −2.7 to −4.9 m/s per °C, water about +2.4 below 74 °C), then add salt on the aqueous side (roughly +11 m/s per wt% NaCl). Above 100 m/s you are safe; 30 to 100 needs a measurement; below 30, don't.

View product · Inline Ultrasonic Phase Separation Detector →

On purchase price alone, ultrasonic and nuclear gauges sit in a similar bracket. The gap opens over 5 to 10 years of ownership.

Hidden cost list of a Cs-137 / Co-60 nuclear gauge:

• Radiation safety licensing and annual reviews, plus operator training and certification;
• Licensed transport and installation filing for the source;
• Dose monitoring and record keeping during service;
• Source replacement as activity decays (purchase, transport, commissioning, return of the old source);
• End-of-life disposal of the spent source — often the single largest bill.

PS7000 acoustic-impedance ultrasonic gauge: no radioactive source and no permits of any kind; non-intrusive sensor that does not project into the flow, so no insertion-type erosion or build-up points, sensor life of 5 years or more, virtually maintenance free with no consumables. Power plant, potash and iron ore sites have run 2+ years at near zero maintenance.

Bottom line: on a 5-year basis the total cost of ownership of the PS7000 is typically far below a nuclear gauge. Where a nuclear principle is genuinely required, a gamma gauge with an exempt-activity Na-22 source is genuinely a lighter route than Cs-137 and needs no license, though the roughly 2.6-year half-life still implies periodic source renewal. We no longer supply that class of instrument; it is noted here for completeness.

View product · Ultrasonic Slurry Density Meter →

The PS7010 external clamp-on type indeed requires no pipe openings, but it does have specific application conditions. Applicable operating scenarios include:

1. Uniform pipe wall material (carbon steel, stainless steel, or copper alloys are all acceptable; plastic or rubber-lined pipes are not suitable);
2. Stable pipe wall thickness (variations in the thickness of internal scale can affect acoustic attenuation readings);
3. Low gas bubble content in the medium (acoustic attenuation is sensitive to bubbles; for bubbly conditions, we recommend the PS7000);
4. Recommended pipe diameters: DN50–DN500.

Installation method: secured with steel band clamps and coated with coupling agent, completed in a few minutes. We also offer on-site ultrasonic coupling tests, with a feasibility report issued within two working days.

View product · Clamp-on Ultrasonic Density Meter →

Eight recipes as standard, each holding a pair of velocity bands and its amplitude threshold; the list extends. Switch from the panel, or let the DCS write a Modbus register — the second follows the batch instruction and removes the "nobody switched it" class of incident.

A product that has never been calibrated needs one pass: two samples, two readings, one stored pair — five minutes, no return-to-factory sampling. Coming back to a known product just recalls its recipe.

When to redo an existing recipe: the composition of that phase moved (water content, salt, product concentration), the temperature band shifted, or acceptance found measured velocity off the stored band by more than the repeatability. Every recalibration records its time and both velocities for the batch record.

View product · Inline Ultrasonic Phase Separation Detector →

The core advantage of the PS7020 sound-velocity method is that it is “unaffected by the appearance of the medium”:

Refractometers rely on light passing through the sample and are severely affected by liquid color, turbidity, and bubbles—dark beverages, brewing liquids containing suspended particles, and bubbly fermentation mash often cause refractometer readings to be inaccurate.

The PS7020 calculates sound velocity by measuring ultrasonic wave propagation time, and is completely independent of color, transparency, electrical conductivity, vibration, noise, and flow rate. Its accuracy is ±0.0005 g/cm³ (density) / 0.5‰ (concentration).

However, the PS7020 is not suitable for extremely dilute solutions—in such cases, the PS7110 refractometer offers higher accuracy.

View product · Inline Ultrasonic Concentration Meter →

No fixed interval — it depends on the duty. What actually helps: the instrument tells you.

As film, crystal or oil builds on the window, the velocity reading does not move at first, but the amplitude baseline drifts down. Trend the clear-phase baseline: a slow decline means clean it; a sharp drop with velocity still in band is an emulsion slug passing, not deposit. The two shapes are easy to tell apart on a trend.

How to clean: sapphire is dense and smooth, so hot caustic, hot water or a normal solvent will do it, usually in place. On duties that will certainly film — edible oil, spent emulsions — put it on the CIP schedule. Afterwards check whether the amplitude baseline came back: that is the acceptance test for the clean.

View product · Inline Ultrasonic Phase Separation Detector →

Yes. The PS7100 employs a full-spectrum UV-Vis-NIR absorption method (200–1,700 nm) combined with an MLR multivariate linear regression algorithm, enabling the simultaneous output of concentrations for multiple components in a single measurement.

Typical applications:

1. In chlor-alkali sodium hypochlorite production, it simultaneously measures effective chlorine and free alkali NaOH (model R² > 0.99);
2. Dual-component analysis of mixed acid solutions (HCl + H₂SO₄);
3. Semiconductor wet etching solutions (HF + HNO₃);
4. Simultaneous monitoring of sugar content and alcohol content in pharmaceutical fermentation broths.

The multi-component capability requires preliminary modeling; Pisonics will develop a dedicated MLR model in its headquarters laboratory based on the customer’s media samples, with a modeling cycle of 2–4 weeks.

View product · Spectroscopic concentration meter →

View product · Refractive concentration meter →

The PS7300 offers three installation configurations:

A—Straight‑tube insertion—vertically inserted through a single hole in the tank roof; this is the most common method and is suitable for atmospheric‑ or low‑pressure storage tanks without agitation or with stable liquid levels (such as finished‑oil tanks and urea solution tanks).

B—Bent‑joint insertion—inserted through a single hole and then bent to a specified depth inside the tank, bypassing agitators or heating coils; this is ideal for large chemical polymerization reactors and MVR evaporation crystallizers.

C—Side‑mount installation—two openings on the tank sidewall, with the diaphragm directly facing the liquid column; this is appropriate for stirred reaction vessels, oil‑gas field three‑phase separators, and horizontal pipeline applications.

Simple guidelines: vertical installation with no obstructions → A; obstacles inside the tank requiring bypass → B; feasible with two side‑wall openings → C.

All three methods have a measurement range of 0–1.0/2.0/3.0 g/cm³, with a resolution of 0.001 g/cm³.

View product · Pipeline Differential Pressure Density Meter →

PS7400 supports flange / tri-clamp / threaded / cable-separated process connections; F1~F6 accessories (bracket, bypass loop, flow cell, flushing port, flanged seat, protective shield) cover inline pipes, open tanks, agitated tanks, scaling media. Insertion lengths: 100 / 150 / 200 / 300 / 400 mm. Selection: inline pipe — insertion = 1/3 to 1/2 pipe diameter, away from wall turbulence; open/storage tank — mid-liquid, away from surface waves and bottom sediment; agitated tank — beyond 1.5× the agitator radius.

View product · Online tuning fork density meter →

The physical basis of microwave measurement lies in differences in dielectric constants: the dielectric constant of water molecules is approximately 80, while that of most solids is around 2 to 10—more than a tenfold difference.

The PS7600 precisely calculates a material’s moisture content, suspended solids concentration, density, and Brix by measuring the phase shift and amplitude attenuation of microwaves as they pass through the medium. This substantial dielectric contrast gives the PS7600 extremely high sensitivity in wet conditions, with typical repeatability better than ±0.01%.

Optimal applications include black liquor in papermaking, evaporation and crystallization in sugar production, concentration monitoring in the food and beverage industries, and sludge. Dissolved salts (conductivity) in the water phase also affect the microwave signal, so where water quality swings widely, calibrate on the site water.

Not suitable for pure organic liquids (such as diesel or pure alcohol); in such cases, it is preferable to use the PS7020 sound‑velocity method or the PS7110 refractometer.

View product · Microwave concentration/density meter →

Typical Pisonics configurations for FGD:

• Limestone slurry tank / absorber recirculation → PS7400 tuning fork, excellent scaling resistance, range 1.0–1.4 g/cm³ covers all normal operating conditions
• Gypsum slurry / discharge pump downstream → PS7300 differential pressure, cost-effective for large-bore main lines
• FGD wastewater (high chloride) → PS7010 ultrasonic attenuation, clamp-on install removes the corrosion-protection problem

Final selection depends on your specific PFD, pipe sizes, temperature, and SO₃ content. Send us your process parameter sheet and we'll return a written sizing proposal within 2 business days.

View industry · Power Emission Control →

Yes.

The Pisonics standard tuning fork density meter PS7400 has a measurement range of 0–150°C, and the standard ultrasonic concentration meter PS7000 covers 0–120°C, which can accommodate most slurry-based hydrometallurgical processes.

For extreme conditions such as high-pressure acid leaching (HPAL) at temperatures above 200°C, we offer custom high-temperature models with titanium alloy or Hastelloy wetted parts, paired with remote transmitters to isolate the electronic components.

Common temperature ranges include: ambient‑temperature slurry (≤ 60°C) / heated flotation (60–90°C) / atmospheric leaching (90–110°C) / high‑pressure leaching (150–250°C) / autoclaves (≥ 250°C, requiring special customization). Please specify the maximum operating temperature when requesting a quote.

View industry · Non-ferrous Mining →

It can, once you separate the two kinds of ternary system.

The exclusion reads “ternary and higher multi-component systems (sonic velocity alone cannot uniquely determine concentration)”. The parenthesis is the operative part. What is excluded is a system whose components move independently. A tail-gas scrubbing loop does not.

There is one reaction in the tower: Cl₂ + 2 NaOH → NaOCl + NaCl + H₂O. Every 2 mol of caustic consumed yields exactly 1 mol of hypochlorite and 1 mol of chloride, so stoichiometry pins all three concentrations to a single reaction path. The composition of the loop is one-parameter: fix how far the reaction has gone and all three numbers follow. One scalar is enough to locate it.

The same arithmetic settles a related question: available chlorine of 10 wt% is residual alkali of 6.7 wt%. The two switch-out criteria plants use are one criterion under two names.

What is genuinely different is a hypochlorite production tower. There chlorine and caustic are dosed independently and the product is accepted on available chlorine and free alkali separately — a real two-dimensional problem needing PS7100 spectroscopy. A tail-gas tower needs one progress number, how much absorbing capacity is left, and PS7020 sound velocity covers it. The application page works it through.

One caveat belongs in the same breath: the scale holds only while the loop stays on that path. Water loss, CO₂ drawn in with air, and HCl in the gas all take it off — and all three err toward showing more alkali than is there. So the meter is operated with margin: alarm at a nominal 8 % residual alkali rather than 5 %, and keep the shift titration.

View industry · Chemical / Fine Chemical →

The two points do different jobs and take different metallurgy; they cannot be ordered to one specification.

① Make-up side (caustic feed line, before mixing): NaOH in water, a textbook binary, calibrated over a narrow 15–20 % span, 316L stainless wetted parts — this side never sees chlorine, so chloride stress-corrosion does not arise.

② Circulating liquor (pump discharge, upstream of the make-up tee): this is where the loop's actual safety margin lives, calibrated over residual alkali 20 % → 5 %. At switch-out the liquor is about 12 % sodium hypochlorite over about 9 % sodium chloride — a pitting and crevice-corrosion duty for 316L — so this one is quoted in titanium. That is what the product page means by “special media, material confirmed against the duty”.

If only one meter fits the budget, fit ②. Make-up strength is normally a purchased specification, verifiable on receipt; the margin in the circulating liquor has no second source.

One installation trap: ② belongs in a full-bore vertical run on the pump discharge, not the tower return line and not the pump suction. Aerated duty is on the PS7020's own exclusion list, and an absorber return line is exactly where entrained gas lives.

View industry · Chemical / Fine Chemical →

The short answer first: if that means a single instrument combining sound velocity with conductivity, no, we do not. It goes first because that is most likely what someone writing the phrase wants, and it is better said while you are drafting the specification than after an award.

The phrase has no agreed definition, though. At least three routes answer to it:

1. Single parameter, along the reaction path — in a tail-gas scrubbing loop, Cl₂ + 2 NaOH → NaOCl + NaCl + H₂O pins the three solutes to one dimension, so a single sound-velocity reading locates how far the reaction has gone. Our PS7020 takes this route.
2. Sound velocity plus a second physical quantity — an independent sensor, usually conductivity, solves for two unknowns. SensoTech document this method for NaOH/NaCl in chlor-alkali electrolysis and list several gas-scrubber duties. We have no instrument of this type.
3. Spectroscopy — a full spectrum and a multivariate model separate two or more components. Our PS7100 takes this route.

Which one you need turns on a single question: how many numbers do you actually need? If the liquor is a consumable and all you want is how much absorbing capacity is left, route 1 is the cheapest that works — residual alkali and available chlorine are the same progress number under two names. If the outlet is sold as product and has to hold free alkali and available chlorine as separate acceptance figures, that is two-dimensional, route 1 cannot do it, and route 3 is the answer.

The full basis, the boundaries of each route, and what we will ask you about your process are at what an “ultrasonic dual-parameter concentration meter” actually means.

View industry · Chemical / Fine Chemical →

No. The clause asks for both, in the same sentence.

Clause 6.1.3 d) reads: “Facilities for online monitoring of the circulating liquor's sodium hydroxide concentration and temperature shall be provided; periodic laboratory analysis shall be carried out; the liquor shall be replaced or renewed before the sodium hydroxide falls below 5 %.” Online and laboratory, together.

Technically they are also both needed, because of one degradation path an online instrument cannot see clearly: carbonation. An emergency absorber sits in standby all year with its ducting and circulation tank open to air, and 2 NaOH + CO₂ → Na₂CO₃ + H₂O slowly consumes free alkali while the total salt content barely changes. On a first-order estimate, each point of free alkali eaten moves sound velocity by only about a fifth of a point's worth; density hardly moves at all. All three online methods read higher than the true free alkali — and this is the main way a standby tower's caustic degrades.

So the division of work is clear. The instrument holds the trend, the step changes and the alarms — dilution, level changes, the sharp fall after an event — in minutes rather than hours. Periodic titration holds the absolute free-alkali figure, and catches carbonation. Treating the instrument as a replacement for the laboratory turns the most dangerous degradation path into a blind spot.

Full treatment on the emergency chlorine absorber page; the method comparison is at how to measure caustic strength.

View industry · Chemical / Fine Chemical →

Typical measurement point configurations for FGD systems:

1. Limestone slurry tank / pulp-making tank outlet → PS7000 acoustic impedance (strong anti-fouling);
2. Absorption tower gypsum slurry / discharge pump main line → PS7000 ultrasonic acoustic impedance (bubble-resistant, non-contact);
3. Flue-gas desulfurization wastewater (chlorine-corrosive) → PS7000 acoustic impedance or PS7400 titanium/ Hastelloy tuning fork;
4. AFT tower high-concentration slurry → PS7000 or PS7400 titanium/ Hastelloy tuning fork;
5. SCR denitrification ammonia water / urea solution → PS7400 tuning fork (medium accuracy) or PS7100 spectroscopy (multi-component).

View industry · Power Emission Control →

Yes. The Pisonics density meter offers tiered temperature and corrosion solutions.

Temperature ratings:

• Normal-temperature slurry ≤ 60°C—standard configuration;
• Heated flotation 60–90°C—select the standard model;
• Atmospheric leaching 90–110°C—select the high-temperature model;
• High-pressure acid leaching (HPAL) 150–250°C—requires customization (use titanium or Hastelloy for wetted materials, and equip with a remote transmitter to isolate the electronic components);
• Autoclaves ≥ 250°C—special customization.

Corrosion-resistant solutions:

• Weak corrosion → 316L;
• Strong acids and alkalis → 2205 duplex stainless steel, Hastelloy C‑276, titanium, or PTFE lining;
• High-abrasion slurry → ceramic probe + PTFE lining.

View industry · Non-ferrous Mining →

Hygienic requirements for food and beverage production:

1. Wetted materials — 316L stainless steel, polished (Ra ≤ 0.4 μm), PTFE, sapphire;
2. Process connections — sanitary clamp (Tri-Clamp), ISO food-grade flanges;
3. CIP/SIP cleaning — resistant to 90°C hot water, chemical cleaning with 3% NaOH/3% HNO3, steam sterilization at 134°C;
4. Dead‑free design;
5. Compliance certificates — FDA 21 CFR, EHEDG, and 3-A certification (for select models).

Pisonics hygienic‑grade versions: PS7400 tuning fork (clamp connection + 316L polishing + PTFE coating), PS7110 refractometer (sapphire prism on the B and C variants, optical glass on the A; tri-clamp or the PS7110-MT4 sanitary adapter, CIP and SIP capable), PS7020 sound velocity method (PTFE wetted parts), PS7210 Coriolis mass flow meter (sanitary clamp).

View industry · Food / Brewing / Sugar →

The primary consideration for measuring strong acids and strong bases is the wetted-material compatibility:

1. Concentrated sulfuric acid (98%) → PS7400 tuning fork (PTFE coating + titanium tines) or PS7110 refractometer (sapphire prism resistant to acids);
2. Sodium hydroxide (NaOH 32% / 48%) → PS7400 tuning fork (PTFE coating + 316L stainless steel) or PS7100 spectrometer (fiber-optic separation, with the main unit housed in a safe area);
3. Hydrochloric acid (HCl) → PS7100 spectrometer (no wetted components) or PS7110 refractometer;
4. Mixed acids (H2SO4 + HNO3) → PS7100 spectrometer (MLR dual-component simultaneous modeling);
5. Hydrofluoric acid (HF) → PS7100 spectrometer or PS7110 refractometer (sapphire resistant to HF).
6. The simultaneous measurement of both effective chlorine and free alkali in chlor-alkali sodium hypochlorite is a signature application case for the PS7100.

View industry · Chemical / Fine Chemical →

Yes. Pisonics offers GMP-compliant versions for the pharmaceutical industry:

1. Wetted materials—316L electropolished, PTFE, and sapphire;
2. Process connections—sanitary Tri-Clamp clamps (DIN 32676 / ISO 2852);
3. Surface finish—Ra ≤ 0.4 μm mirror polish;
4. Validation documentation—IQ/OQ validation documents, material traceability certificates (EN 10204 3.1), and surface roughness reports are provided upon shipment;
5. CIP/SIP compatibility—withstanding steam sterilization at 134°C.

Typical applications: sugar/alcohol concentration in fermenter external circulation lines (PS7110 refractive index), concentration during injection solution preparation (PS7210 Coriolis), API crystallization (PS7300 differential pressure), and PAT process analysis (PS7100 spectroscopy). It has also passed a 21 CFR Part 11 audit.

View industry · Pharma / Biotech →

The core requirements for density meters in custody‑transfer applications are as follows:

1. Absolute accuracy—typically ≤ ±0.001 g/cm³, with high‑standard projects requiring ≤ ±0.0005 g/cm³;
2. International certifications—compliance with metrological regulations such as OIML R117, API MPMS 11.1, and the MID;
3. Long‑term traceability—zero drift within 12 months ≤ 0.0005 g/cm³, traceable to the national metrology standard;
4. Temperature and pressure compensation—built‑in PT100 for real‑time temperature and pressure correction;
5. Data storage—cyclic storage of thousands of transfer records;
6. Explosion protection—petroleum product transfer areas generally require Exd II B T4 or higher.

We recommend: PS7400 tuning fork (for refined oil / liquefied gas / marine fuel) and PS7210 Coriolis (for high‑precision measurement).

View industry · Oil & Gas / Petrochemical →

Challenges in water treatment and sludge processes:

1. Diverse impurities—fibers, hair, plastic fragments, and other filamentous materials that can easily wrap around contact-type instruments;
2. Serious scaling—phosphate and calcium ions in the sludge dewatering stage lead to solid deposits adhering to probes;
3. Corrosiveness—wastewater pH fluctuates widely (4–10);
4. High gas content—abundant bubbles in the aeration section interfere with conventional ultrasonic and transmission-refractometric instruments.

Recommended solutions: PS7000 ultrasonic acoustic impedance (for aeration tanks with numerous bubbles), PS7010 external‑mounted ultrasonic (for non‑perforable older pipelines, with zero hair entanglement), PS7400 tuning fork with PTFE coating (for the sludge dewatering stage, resistant to scaling), PS7600 microwave (for advanced dewatering of municipal sludge).

View industry · Water & Wastewater →

It is necessary. AI data center liquid cooling (cold‑plate and immersion types) typically uses aqueous solutions of ethylene glycol (EG) or propylene glycol (PG), with concentrations ranging from 30% to 50%. The importance of precise concentration control: too low a concentration → insufficient freezing point, posing a risk of pipe freezing in northern winters; too high a concentration → increased viscosity, leading to higher pump energy consumption and reduced heat transfer efficiency.

Drift sources:

1. Dilution due to system makeup water;
2. Local concentration increases as the evaporative section under high load preferentially removes water;
3. Slow oxidation and decomposition of ethylene glycol.

Recommendation: PS7400 tuning fork density meter (density accuracy ±0.001 g/cm³, convertible to concentration accuracy ±0.5%), installed in the main loop of the heat exchanger.

View industry · Data Center / HVAC Liquid Cooling →

The core electrolyte in the lithium‑battery copper‑foil electroplating process consists of copper sulfate (CuSO4), dilute sulfuric acid (H2SO4), and additives; precise concentration control directly determines the copper foil’s thickness uniformity, grain size, and tensile strength.

Measurement challenges:

1. The medium is highly corrosive (H2SO4 + Cu2+);
2. The concentration fluctuation range is very narrow (CuSO4 typically 60–80 g/L, requiring control within ±2 g/L);
3. The site temperature varies significantly (25–55°C);
4. The presence of trace additives (gelatin/SPS) affects certain principle‑based instruments.

Recommendations:

1. PS7100 spectroscopic method—MLR multicomponent modeling enables simultaneous measurement of Cu2+ concentration, H2SO4 concentration, and additive concentration;
2. PS7020 sound velocity method—single‑component density accuracy of ±0.0005 g/cm³, with a PTFE lining for acid resistance.

View industry · New Energy / Battery Electrolyte →

Challenges posed by the environment of dredging vessels (cutter suction dredgers, trailing suction hopper dredgers, and sand‑suction vessels) to instrumentation:

1. Continuous vibration—vibration from the main engine, mud pump, and cutter ranges from 0.5 to 5 g;
2. Salt‑mist corrosion—seawater aerosols severely corrode the enclosures of electronic instruments;
3. Coarse‑sand abrasion—the slurry contains coarse sand with particle sizes ≤ 50 mm;
4. Cross‑border operations—nuclear‑source density meters are subject to cumbersome approval procedures for international transport licenses.

Recommended: PS7000 ultrasonic acoustic impedance concentration meter—

1. Flange‑mounted direct‑insertion design with a non‑contact probe, eliminating wear;
2. The ceramic probe withstands continuous erosion by sand and gravel, with a service life ≥ 5 years;
3. IP65 rating; explosion‑proof ExdⅡCT6Gb optional;
4. Completely non‑nuclear;
5. 4G module optional, enabling the fleet headquarters to monitor all operating vessels in real time.

View industry · Dredging Vessels →

The core measurement requirements for paper‑making black liquor (digestion waste liquor, containing lignin and alkali) and white liquor (a mixture of NaOH and Na2S) are as follows:

concentration monitoring, recovery efficiency, and energy‑saving control.

Black liquor conditions: high viscosity (500–3,000 cP), dark color (optical methods are not applicable), temperature 70–150°C, and presence of fine particles.

We recommend the PS7600 microwave density meter (dielectric sensitivity to water allows measurement of solids content and concentration) or the PS7020 sound velocity method (immune to color interference).

White liquor conditions: strong alkaline corrosion, temperature 80–120°C.

We recommend the PS7400 tuning fork (with PTFE coating). The PS7110 refractometer also reads white liquor concentration, but only where the process stays at or below 100 °C — the C variant tops out there, and anything hotter is out of range. For green liquor (the precursor to recovered white liquor), refer to the black liquor solution.

View industry · Pulp & Paper →

The mud–water balance density measurement in tunnel boring machines is a key parameter for stabilizing the excavation face.

Typical operating conditions:

1. Inflow slurry density: 1.05–1.20 g/cm³;
2. Outflow slurry density: 1.20–1.40 g/cm³ (containing cuttings);
3. The slurry contains coarse sand and gravel with particle sizes ≤ 50 mm;
4. Severe on-site vibration, high humidity, and heavy condensation.

We recommend the PS7000 ultrasonic acoustic impedance concentration meter:

1. Flanged direct‑insertion design with a non‑contact probe, eliminating wear;
2. Sapphire probe resistant to sand and gravel erosion;
3. Chirp algorithm suppresses bubble interference;
4. IP65 rating; explosion‑proof ExdⅡCT6Gb optional;
5. 4–20 mA + Modbus connectivity to the TBM’s main PLC, enabling real‑time feedback of the inflow–outflow density difference to support chamber pressure adjustment.

View industry · Tunnel Boring (TBM) →

In semiconductor wet‑process operations (etching, CMP, cleaning), ultrapure chemicals (HF, H2SO4, H3PO4, KOH, etc.) are used, placing the following requirements on density meters:

1. Wetted materials must ensure zero metal ion contamination—sapphire, PTFE, and Teflon‑PFA.
2. High concentration accuracy is required (a deviation of ≤ 0.1 wt% can affect product yield).
3. Simultaneous measurement of multiple components is needed (e.g., a mixed etchant of HF + HNO3 + H2SO4).
4. A hygienic surface finish is essential to prevent particle contamination.
5. Long‑term stability is critical, as semiconductor production lines operate 24/7 without downtime.

Recommended models: PS7100 spectral method (multi‑component MLR modeling, no wetted body, sapphire window); PS7110 refractometer (sapphire prism resistant to HF); PS7020 sound velocity method (PTFE wetted parts, highly acid‑resistant).

View industry · Semiconductor / Wafer FAB →

Start with the fluid, then look at accuracy.

An EG loop can take either. The PS7400 tuning fork measures density and converts to concentration through a built-in curve at ±0.5 vol%; it goes straight into the main line with no bypass, which is the least trouble. The PS7110 measures refractive index at ±0.1 vol% — an order of magnitude better — at the cost of a sample bypass and of keeping the prism clean. Where top-ups are frequent and the concentration has to stay inside a narrow band, that trade is worth making. Where the question is only whether the loop has drifted somewhere dangerous, the fork is enough.

A PG loop: refractometer or fork, but not sound velocity. See the next question.

One practical point that has nothing to do with the principle: an outdoor dry-cooler loop can fall below 0 °C in winter. The PS7110-B stops at 0 °C, so that duty needs the PS7110-C (−10 to 100 °C).

View industry · Data Center / HVAC Liquid Cooling →

No. Sound velocity is monotonic in ethylene glycol over the working range, but in propylene glycol it folds back mid-range — the curve turns over, one sound velocity corresponds to two concentrations, and the instrument cannot tell which branch it is on. There is no acoustic route to PG, so the PS7020 sound-velocity method does not apply to a PG loop.

Refractive index is monotonic across the range for both EG and PG, so PG concentration goes to refractometry (PS7110) or to density (PS7400 tuning fork).

While we are here, a limitation of the optical route itself: refractive index cannot tell PG from EG. At 25 vol% the two differ by about 0.0002 RI, while 1 vol% of concentration is about 0.001 RI. So the make-up fluid has to be controlled — the instrument must be told which fluid it is reading rather than left to guess. Top a PG loop up with EG and the reading will look entirely reasonable.

View industry · Data Center / HVAC Liquid Cooling →

Yes, provided the sensor face stays submerged under every operating condition. That comes from the mounting height: the lower half of the side wall, below the lowest operating level and above any deposit at the invert. On a DN600 line with the sensor 45° below the centreline, the level must never fall below 160 mm.

When the level drops below the window or the line runs dry the reading is invalid and the meter raises no fault code, so gate it in the DCS with feed flow or level.

View case · Coal slurry thickener feed and underflow: online solids concentration →

Yes — high, not low. Fine dispersed bubbles matter little; free gas from pump suction, a falling stream or a mixing point makes the reading high, and a dose-per-dry-tonne feed-forward then overdoses.

That is why the sensor goes on the full line after the feed pump, upstream of the conditioner and the reagent point, and why the gas index is used as a quality flag: above its set point the DCS holds the last good concentration.

View case · Coal flotation feed: online solids concentration →

A film can form, but the mechanism is different. The sapphire window is flush with the pipe wall, so there is no tine root or gap for flocs to lodge in. If the window does foul, the reading creeps up and flattens while echo energy and signal quality change with it — visible, not silent. Put the point on the routine inspection round and fit a flush connection.

View case · Coal slurry thickener feed and underflow: online solids concentration →

Two reasons. Dosed slurry goes through a conditioner or agitated tank that works air into it, and oily collectors such as diesel or kerosene can film the window and hold fine slime on it, so the reading creeps up. Upstream of the reagent point the window sees undosed slurry.

Wherever it sits, put the point on the inspection round and fit a flush connection.

View case · Coal flotation feed: online solids concentration →

No. With the pump stopped the slurry settles in the line, solids gather at the sensor and the reading climbs slowly and unnaturally smoothly; none of it is a process value. Gate the measurement with the pump-running signal and hold the last good value while stopped. A genuine instrument fault drives the loop to a fault current instead (3.5 mA by default, per NAMUR NE43).

View case · Coal slurry thickener feed and underflow: online solids concentration →

Savings belong to the dosing system as a whole — the feed-forward model, ash feedback, the dosing actuators and how the circuit is run. The concentration meter is one input, so we do not promise a saving for the instrument on its own.

What we do commit to is the measurement: gravimetric comparisons during the trial, with the acceptance figure agreed from their mean bias and standard deviation.

View case · Coal flotation feed: online solids concentration →

The specification gives ±1 % by mass concentration, which is one percentage point. On a 50–100 g/L feed that is about ±10–11 g/L, or 11–21 % of reading: neither a fair description of performance nor a useful acceptance figure, and narrowing the 4–20 mA span does not change the instrument's uncertainty.

Agree the feed criterion from the standard deviation of gravimetric comparisons made during the trial. On the underflow, at 200–450 g/L, ±1 % is about 3–6 % of reading and the specification is a reasonable basis.

View case · Coal slurry thickener feed and underflow: online solids concentration →

You get the concentration trend but not dry solids to flotation. Dosing per dry tonne needs a flow signal on the same stream, usually from an electromagnetic meter, multiplied with concentration in the DCS or dosing PLC; PS7000 supplies concentration over 4–20 mA or Modbus.

View case · Coal flotation feed: online solids concentration →