Sealed Terminal Block Assembly for Process Transmitter
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Solution Overview
Problem
Existing process variable transmitters face challenges in harsh environments due to exposure to moisture and contaminants, leading to increased manufacturing costs and complexity from the use of potting materials and sensitive RFI filters, which can be damaged or difficult to install.
Innovation Solution
A process variable transmitter design featuring a housing with a sealed electronics compartment and a terminal block assembly that eliminates the need for potting, using a metal shroud to protect electronics and provide a flexible, modular configuration, allowing for easier maintenance and reduced component sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional potting materials and RFI filters are used to protect electronics, then protection against moisture and contaminants is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The transmitter housing is divided into separate compartments: a sealed process fluid compartment and an electronics compartment. The terminal block assembly includes its own sealed enclosure that isolates electronics from the process environment, eliminating the need for potting materials while maintaining protection.
Solution Approach 2:
A sealed barrier or membrane separates the process fluid compartment from the electronics compartment, allowing electrical connections while preventing moisture and contaminant ingress. This intermediary structure replaces the need for complex potting and filtering systems.
2Reliability
If traditional potting materials and RFI filters are used to protect electronics, then protection against moisture and contaminants is improved, but manufacturing cost increases
Solution Approach 1:
The terminal block assembly is manufactured as a separate, pre-sealed unit with integrated electronics protection. This modular approach simplifies manufacturing by allowing the sealed enclosure to be produced independently and then assembled into the final transmitter, reducing overall manufacturing complexity and cost.
Solution Approach 2:
The sealed terminal block enclosure provides adequate protection without requiring expensive potting materials or complex RFI filtering systems. The design uses cost-effective sealing methods that achieve the necessary protection level at lower manufacturing cost.
3Reliability
If RFI filters are used to protect electronics, then protection against electromagnetic interference is improved, but ease of installation and maintenance deteriorates due to sensitivity and installation difficulty
Solution Approach 1:
The terminal block assembly integrates electrical connections, electronics mounting, and EMI protection into a single pre-assembled unit. This eliminates the need for separate RFI filter installations and simplifies both initial installation and future maintenance, as the entire assembly can be replaced as one unit if needed.
Solution Approach 2:
The sealed terminal block enclosure provides inherent EMI protection through its structural design and sealing, eliminating the need for additional complex filtering components that require careful installation and maintenance. The design is self-protecting through its modular sealed construction.
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
A process variable transmitter (100) for use in an industrial process includes a housing (102) having a cavity formed therein. The housing has a barrier (120) which divides the cavity into first (104) and second (106) cavities. Preferably, measurement circuitry (110) in the first cavity (104) is configured to measure a process variable of the industrial process. A terminal block assembly (108) is positioned in the second cavity (106). The terminal block assembly (108) forms a seal with the housing (102) thereby forming a third cavity (108) between the barrier and a circuit board of the terminal block assembly.