In the field of flow measurement for highly corrosive media, HHD electromagnetic flowmeters stand out with their unique FKM lining structure. This article provides an in-depth analysis of the 7 core characteristics of FKM lining, revealing how LDG, HK-LDE and other series of electromagnetic flowmeters maintain stable measurement in harsh environments such as chemical and metallurgical industries.

I. Definition and Overview of the Characteristics of FKM Lining

FKM (fluoroelastomer) is a composite material of fluorocarbon compounds and rubber, specially designed to resist corrosion from strong acids, strong alkalis and organic solvents. HHD electromagnetic flowmeters adopt insert-type FKM lining technology, and its characteristics include:

• Chemical inertness: Resistant to more than 98% of industrial chemicals, including concentrated sulfuric acid and hydrofluoric acid
• Wide temperature adaptability: Stable operation at -40℃~150℃, covering the vast majority of industrial scenarios
• Low permeability: Dense molecular structure prevents medium penetration from causing electrode corrosion
• High mechanical strength: Tensile strength ≥15MPa, avoiding damage from medium scouring
• Electrical insulation: Volume resistivity >10^15Ω·cm, ensuring accurate signal transmission
• Food-grade certification: Complies with FDA 21 CFR 177.2600 standard, suitable for the food and pharmaceutical industries
• Long service life design: Laboratory accelerated aging tests show a service life of over 10 years

II. Comparative Analysis of Technical Performance Parameters

Compared with ordinary rubber-lined electromagnetic flowmeters, the HHD series with FKM lining performs outstandingly in key indicators:

III. Analysis of Typical Application Scenarios

Under the following harsh working conditions, electromagnetic flowmeters such as ZK-LDC and HY-LD perform particularly well:

1. Electroplating production lines: Measuring the flow of electrolytes containing chromic acid and cyanides, traditional flowmeters are corroded through in just 3 months, while the HHD series can operate stably for more than 5 years
2. Phosphorus chemical industry: For 98% concentrated phosphoric acid transfer metering, the FKM lining maintains 0.5% measurement accuracy
3. Chlor-alkali engineering: For 32% caustic soda solution metering, the electrodes use special Hastelloy alloy + FKM dual protection
4. Semiconductor industry: Ultra-pure water systems require ppb-level cleanliness, and the lining material is certified to SEMI F57

IV. Technical Guide for Procurement and Selection

When selecting electromagnetic flowmeters such as the W3000 and Magne series, attention should be paid to:

• Media compatibility verification: Require the supplier to provide a material corrosion resistance test report
• Structural design: Check whether an integral sintering process is adopted to avoid leakage at joints
• Electrode configuration: For highly corrosive media, it is recommended to choose tantalum electrodes + FKM combination
• Certification standards: Confirm compliance with the national standard GB/T 18659-2018 Electromagnetic Flowmeter

V. Solutions to Common Problems

Q: Does FKM lining affect measurement accuracy?
A: Actual test data of the PLUS series show that at a flow velocity of 0.5m/s, the effect of the dielectric constant of FKM lining (2.1) and ordinary rubber (2.8) on accuracy is less than 0.1%, fully meeting the 0.5 accuracy class requirements.

Q: How can you determine whether the lining needs to be replaced?
A: The lining should be inspected when the following conditions occur: ① flow signal fluctuation >10% ② zero drift >3% of full scale ③ electrode insulation resistance <50MΩ. The ZK-LDE series is equipped with a lining health monitoring function for early warning.

VI. Why Choose Xi'an Shenghongchuang

As a national high-tech enterprise, we provide the following for the full range of electromagnetic flowmeters such as ZYLDE and HHD:

• 72-hour corrosion resistance simulation testing service
• 10-year lining warranty commitment
• ISO 9001:2015 quality management system certification
• Direct supply from the intelligent manufacturing base in Xixian New Area

Consult our technical engineers now to obtain the Corrosive Media Flowmeter Selection Manual, hotline: 029-xxxxxxx.