Magnetic Flowmeter Liner Mechanical Fastening
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Solution Overview
Problem
Magnetic flowmeter liners made of polytetrafluoroethylene (PTFE) tend to shift during handling and installation, leading to potential leaks or electrode shorts, and existing solutions either use hazardous chemicals for bonding or rely on proper handling instructions, which are not always followed.
Innovation Solution
The use of mechanical fasteners to secure the liner to the flowmeter sensor, ensuring they do not extend beyond the planar sealing surfaces, preventing shifting without the need for hazardous chemicals or relying on correct installation procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive bonding is used to secure the liner to the sealing surfaces, then the liner is prevented from shifting, but hazardous chemicals are required to overcome PTFE's resistance to chemical attack
Solution Approach 1:
The patent replaces the chemical bonding system (adhesives requiring hazardous chemicals to bond to PTFE) with a mechanical fastening system (clamps or bands that apply mechanical pressure). This substitution eliminates the need for hazardous chemicals while achieving the same goal of preventing liner shifting during installation and operation.
2Object-affected harmful factors
If the liner is left unbonded and reliance is placed on handling instructions, then no hazardous chemicals are used, but the liner is susceptible to shifting during handling and installation
Solution Approach 1:
The mechanical fastening system is self-applying and self-regulating. Once the clamps or bands are installed, they automatically maintain constant pressure on the liner without requiring ongoing human intervention or adherence to handling instructions. The system serves itself to maintain liner positioning throughout installation and operation.
3Ease of manufacture
If the liner is flared onto the sealing surfaces, then the liner is secured in position, but the elastic nature of PTFE causes the liner to spring back and create gaps at the sealing surfaces
Solution Approach 1:
The mechanical fastening system is applied in advance to counteract the spring-back effect. By securing the liner with clamps or bands before the flange bolts are fully tightened, the system prevents the liner from springing back and creating gaps, ensuring continuous contact with the sealing surfaces throughout the installation process.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A magnetic flowmeter sensor includes two sensor faces, a conduit, a liner lining the conduit, and mechanical fasteners. The sensor faces are on each end of the sensor for connecting the sensor to the process fluid flow. The conduit connects the two sensor faces for conducting the process fluid flow through the sensor. The liner extends across at least a portion of each sensor face at each end of the flowmeter sensor to form a planar sealing surface on each end of the sensor. The liner includes holes through which the mechanical fasteners pass to mechanically attach the liner to the flowmeter sensor to prevent shifting of the liner. The mechanical fasteners do not extend beyond the planar sealing surfaces.