Henan Zhongce Sensor Scraper-Type Electromagnetic Flowmeter: A High-Reliability Flow Measurement Solution for Applications Prone to Scaling

In industrial applications such as wastewater treatment, slurry transportation, and pulp and paper manufacturing, electromagnetic flowmeters often experience deposition of suspended solids, crystalline substances, or fibers on the electrode surfaces after prolonged operation, forming an adherent layer. This fouling can lead to signal attenuation or even open-circuit conditions, resulting in measurement drift or instrument failure. To address this industry challenge, Henan Zhongce Sensor Manufacturing Co., Ltd. has introduced a scraper-type electromagnetic flowmeter that employs a mechanical scraping mechanism to clean the electrode surfaces online, providing a stable flow-measurement solution for applications prone to scaling and fouling.

I. Introduction to Henan Zhongce Sensor Manufacturing Co., Ltd.

Henan Zhongce Sensor Manufacturing Co., Ltd. was established in December 2023, with its registered address at No. 181 Changxing Road, Changxing Road Subdistrict, Changge City, Xuchang, Henan Province. The company’s registered capital is RMB 3 million, and its legal representative is Hu Yujie. The company operates in the instrument and meter manufacturing industry, with a business scope that includes the manufacture and sale of instruments and meters, the manufacture of smart instruments and meters, the manufacture and sale of industrial automatic control system equipment, information system integration services, software development, and import and export of technology, among other activities.

Since its establishment, the company has focused on the industrial automation instrumentation sector, with a product portfolio that includes electromagnetic flowmeters, smart instruments and meters, and industrial automatic control system equipment. The company is committed to providing flow measurement products and solutions for industries such as wastewater treatment, chemical processing, papermaking, and food manufacturing.

II. Working Principle of Scraper-Type Electromagnetic Flowmeters

The fundamental measurement principle of scraper-type electromagnetic flowmeters is the same as that of conventional electromagnetic flowmeters: it is based on Faraday’s law of electromagnetic induction. When a conductive fluid flows through the measuring tube and cuts across the magnetic field lines, the electrodes detect the induced electromotive force, which is then converted into the instantaneous flow rate and the total accumulated flow.

The key difference lies in the addition of a mechanical scraping device. The scraper assembly is tightly pressed against the electrode surface and driven—either by an electric motor or manually—to perform either rotary or reciprocating motion. Depending on operational requirements, it can be configured for timed cleaning or trigger-based cleaning. Importantly, the cleaning process does not require shutdown, ensuring uninterrupted media conveyance and accurate flow measurement.

III. Product Structure Characteristics

1. Scraper Cleaning Mechanism

The scraper is made of stainless steel and features a slender shaft that extends through a hollow electrode; a mechanical seal is installed between the shaft and the hollow electrode to prevent leakage of the process medium. During operation, open the electrode cover on the meter body and rotate the slender shaft to drive the scraper in tight contact with the electrode’s end face, thereby removing surface fouling. This scraping can be performed while the flowmeter is in operation; after cleaning, simply rotate the scraper so that its orientation aligns with the direction of fluid flow.

2. Lining and Electrode Materials

The liner material for the measuring tube can be selected flexibly based on the characteristics of the process medium: for abrasive media containing solid particles (such as mineral slurry), polyurethane rubber (PU) is recommended due to its excellent wear resistance; for corrosive media (such as chemical slurries), PTFE or FEP is suitable because of their outstanding chemical stability; and for hygienic applications (such as food-grade slurries), hygienic-grade PTFE is preferred, as it supports online cleaning.

Electrode materials are selected based on the corrosivity gradient of the process medium: 316L stainless steel is used for conventional sewage or slurry; Hastelloy C and titanium alloys are used for corrosive media; and tantalum electrodes are recommended for highly corrosive media.

IV. Technical Advantages

1. Online cleaning to reduce downtime for maintenance

Conventional electromagnetic flowmeters require disassembly and cleaning of the electrodes when fouling occurs, which disrupts production continuity. In contrast, scraper-type electromagnetic flowmeters enable on-line electrode cleaning without interrupting the process, thereby reducing operation and maintenance costs.

2. Ensuring Long-Term Measurement Accuracy

Promptly remove deposits from the electrode surface to maintain good contact between the electrode and the process medium, thereby preventing signal attenuation. In practical applications, long-term measurement accuracy can be maintained within the range of ±0.5% to ±1.0%.

3. Suitable for Harsh Operating Conditions

Capable of measuring conductive fluid media with high viscosity, high solids content, and a tendency to crystallize or form scale, it is suitable for a wide range of complex media, including sewage, sludge, pulp, mineral slurries, and food slurries.

4. Strong functional scalability

Supports 4–20 mA analog output, pulse/frequency output, and RS485 communication interface, enabling integration with host systems such as PLCs and DCSs for remote parameter configuration and data acquisition.

V. Applicable Industries and Typical Media

Scraper-type electromagnetic flowmeters are widely used in the following industrial sectors:

Wastewater treatment : Measure the flow rates of wastewater, activated sludge, digested sludge, and other similar materials.

Chemical industry : Measures the flow rate of acidic, alkaline, and saline solutions, as well as slurries and suspensions containing solid particles or fibers.

Paper-making industry : Measuring the flow rate of media such as pulp and black liquor.

Mining and Metallurgy : Measuring the flow rate of abrasive media such as mineral slurry and tailings.

Food industry : Measures the flow rate of pulpy or fibrous fluids such as fruit juices, jams, and tomato sauces.

Petrochemical : Measures the flow rate of various conductive process media.

VI. Reference Factors for Model Selection

When selecting a scraper-type electromagnetic flowmeter, it is recommended to comprehensively evaluate the following factors:

Medium Properties The medium’s composition, solids content, viscosity, temperature, pressure, and corrosivity determine the selection of lining and electrode materials.

Flow range : Select an appropriate range based on the actual process flow rate; the typical flow velocity range is generally maintained at 0.5. ~ 10 m/s; the recommended flow velocity is 1.5. ~ 5 m/s.

Caliber matching : When selecting a conventional scraper-type electromagnetic flowmeter, the minimum nominal diameter is generally not less than DN80; however, the specific requirement shall be subject to the manufacturer’s actual product specifications.

Cleaning Mode : For continuous production operations, a scheduled cleaning mode is recommended; for batch production operations, either manual cleaning or trigger-based cleaning may be selected.

Installation Environment : Consider factors such as ambient temperature, humidity, vibration, and electromagnetic interference. In areas with an explosion hazard, explosion-proof products must be selected.

VII. Installation and Maintenance Recommendations

Installation Key Points ：

The measuring tube shall be kept fully filled with the process fluid at all times; vertical installation is preferred, with the fluid flowing from bottom to top, to minimize deposition.

When installed horizontally, the electrodes should be positioned in the horizontal plane of the pipeline to ensure more thorough cleaning by the scraper.

Straight pipe sections of the required length shall be provided upstream and downstream of the flowmeter to ensure measurement accuracy.

The installation location should be free from strong magnetic fields and significant vibration sources, and adequate ventilation and dry conditions must be ensured.

Maintenance and Operation Recommendations ：

Arrange cleaning intervals appropriately based on the rate of fouling in the medium, and periodically rotate the scraper to remove deposits from the electrode surface.

The scraper should be operated while the instrument is running; after cleaning, rotate the scraper so that its orientation aligns with the fluid flow direction (direction indicators are usually marked on the knob).

Regularly inspect the condition of the mechanical seal to ensure proper sealing performance.

Note that blade-type electrodes are limited by shaft seals and are generally not suitable for applications with pressures exceeding 10 MPa.

VIII. Summary

Henan Zhongce Sensor Manufacturing Co., Ltd. has launched a scraper-type electromagnetic flowmeter that addresses the challenging measurement conditions posed by media prone to scaling and deposition. By incorporating a mechanical scraping mechanism, the meter enables on-line cleaning of the electrode surface, thereby effectively maintaining measurement accuracy and stability over long-term operation. The product is compatible with a wide range of liner and electrode materials, making it suitable for diverse operating conditions across industries such as wastewater treatment, chemical processing, papermaking, mining, and food processing. It represents a flow-measurement solution that balances reliability with ease of maintenance.