PISONICS· Xi’an Pisonics
PS7000 Series
Ultrasonic Acoustic Impedance Slurry Density Meter
Case Study: Dredging Projects / Cutter Suction Dredgers
—— Online Slurry Density Monitoring Solution for Cutter Suction Dredgers, Hopper Dredgers, and Sand‑Sucking Vessels ——
Non‑Nuclear · Resistant to Sand and Gravel Erosion · 4G Remote Cloud Connectivity · Clog‑Prevention Alarm
Dredging Projects / Cutter Suction Dredgers · PS7000 Application Solution
1. Process Background
Dredging is a core component of major infrastructure projects, including port construction,channel maintenance, land reclamation by hydraulic fill, and river and lake sediment removal. During operations, dredging vessels such as cutter suction dredgers, hopper dredgers, and sand‑sucking ships use cutting tools to excavate bottom sediments, then pump the water–soil mixture in slurry form through long pipelines to reclamation sites or disposal areas. The key performance indicator—soil production per unit time—is directly determined by “slurry density × flow rate”.
The ideal operating density of the discharged slurry typically ranges from 1.15 to 1.35 g/cm³, depending on soil type. Too low a density indicates insufficient soil content, resulting in low hourly output and severe energy waste; too high a density can cause slurry pumps to clog, reduce head, and, in severe cases, lead to “stall” incidents—backflow in the discharge pipeline and emergency shutdowns—with single‑event losses ranging from hundreds of thousands to over a million yuan.
2. Pain Points of Traditional Density/Concentration Measurement Solutions
• Traditional nuclear density meters: While accurate, their use on board requires permits for the transport of radioactive sources, and cross‑border operations (e.g., in Southeast Asia, Africa, and the Middle East) involve cumbersome approvals, along with stringent crew protection and annual inspection requirements.
• Differential pressure or tuning fork density meters: Their diaphragms are in direct contact with highly abrasive slurries containing particles up to 50 mm in size, leading to an average service life of less than six months and frequent failures due to wear and perforation.
• Slow response: Conventional instruments take 5–10 seconds or more to provide readings, making it impossible for the bridge to detect sudden density spikes when the cutter hits the seabed—often only becoming apparent after a pump has already clogged.
• The combined environment of ship vibration, high humidity, salt spray, and strong electromagnetic interference places extremely high demands on instrument protection levels and anti‑interference capabilities.
3. PS7000 Solution
The PS7000 is installed on the main discharge line at the outlet of the cutter suction dredger’s mud pump, using a flanged direct‑insertion mounting. Ultrasonic waves are emitted from transducers mounted on the outer pipe wall, and the returning echoes are analyzed to extract acoustic impedance signatures—without any direct contact with the abrasive slurry, eliminating wear and blockage concerns. The ceramic transducers withstand continuous erosion by sand and gravel, with a service life of at least five years.
Figure 1: Schematic of Online Slurry Density Monitoring for Cutter Suction Dredgers
Core Technical Advantages of the PS7000 in Dredging Projects and Cutter Suction Dredger Operations ▶ Completely non-nuclear—no need to obtain a permit for the waterborne transport of radioactive sources; projects both domestically and internationally can be deployed with ease; ▶ Ceramic wear-resistant probe—withstanding continuous erosion by coarse sand particles up to 50 mm in diameter, far surpassing traditional contact-type instruments; ▶ Response time < 1 second—when the cutter hits the seabed, the instantaneous density jump can be immediately detected on the bridge, enabling proactive adjustment of the cutter arm height to prevent pump blockage; ▶ 4–20 mA + MODBUS-RTU + optional 4G module—allowing fleet headquarters to monitor in real time the production and energy efficiency of all operating vessels; ▶ IP65 + ExdⅡCT6Gb explosion-proof option—meeting the demanding onboard environment of high humidity, salt spray, and vibration; ▶ Multiple PS7000 units can be deployed simultaneously to calculate the output of multiple parallel slurry pipelines and monitor the water-to-soil ratio. |
4. Customer Value
Comparison Dimensions | Original Conventional Solution | PS7000 Solution |
Operational Safety | Radiation source control / Cumbersome permitting | Non-nuclear source · No barriers in international projects |
Instrument service life | Differential pressure diaphragm worn through in less than June | Ceramic probe with ≥ 5 years of maintenance-free operation |
Response Speed | 5–10 seconds of lag | < 1 second real-time sensing |
Pump Clogging Incident | It was only after the accident that we realized | Density jump → Real-time early warning |
Fleet Management | Local instruments · Difficult to aggregate | 4G cloud connectivity · Fleet-level supervision |
At a large port expansion project in China, a cutter suction dredger belonging to a major dredging contractor replaced its original nuclear density meter with the PS7000, thereby eliminating the burdens of cross‑border transport of radioactive sources and routine safety management. After one year of operation, pump clogging incidents decreased by more than 60% year‑on‑year, daily operating time per vessel increased by over 1.5 hours, and overall annual benefits improved significantly. Similar solutions have been successfully deployed in coastal port dredging, inland waterway desilting, and overseas land reclamation projects.
Conclusion
Based on the four ultrasonic measurement principles of the PS70 series—acoustic impedance, acoustic attenuation, sound velocity, and sonar frequency modulation—Xi’an Pisonics (PISONICS) covers all operating conditions, from solid–liquid two‑phase slurries to clean, homogeneous liquids, meeting diverse online density and concentration measurement needs. Tailored to the process characteristics of dredging and cutter suction dredging, the PS7000 series ultrasonic acoustic impedance slurry density meters provide end‑to‑end technical support, from instrument selection and installation/commissioning to long‑term maintenance and operation.
For an in‑depth discussion of your project’s specific conditions, customized selection recommendations, or on‑site technical consultation, please feel free to contact the technical engineering team at Xi’an Pisonics at any time.
