Sealed Terminal Box for Heating Circulating Pumps
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Solution Overview
Problem
Heating circulation pumps face challenges in maintaining the reliability and longevity of moisture-sensitive motor electronics, especially in humid environments, due to unsatisfactory sealing and potential electrical shock hazards, which also increase manufacturing and assembly costs.
Innovation Solution
A sealed terminal box design using material-fit connections between thermoplastic components, eliminating the need for seals and screw connections, ensuring a hermetically sealed and durable enclosure for motor electronics, with features like snap connections and laser welding for assembly and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional terminal box designs with unscrewable covers and seals are used, then assembly and disassembly are easier, but sealing reliability deteriorates over time due to seal ageing and electrical shock hazards increase
Solution Approach 1:
The terminal box is divided into two separate parts (housing and cover) that are connected through material fit (ultrasonic welding or adhesive bonding) rather than mechanical fastening. This segmentation allows each part to be optimized independently while achieving superior sealing through the material-fit connection, eliminating seal ageing issues.
Solution Approach 2:
The traditional mechanical screw connection and seal system is replaced with a material-fit connection method (ultrasonic welding or adhesive bonding). This substitution eliminates the need for separate seals and mechanical fasteners, providing hermetic sealing without the complexity of traditional assemblies and avoiding electrical shock hazards from unscrewable covers.
2Ease of manufacture
If thermoplastic components with material-fit connections are used, then manufacturing costs are reduced and sealing is improved, but assembly requires specialized welding equipment
Solution Approach 1:
Traditional mechanical assembly methods (screws, clips, snap-fits) are replaced with material-fit connections using ultrasonic welding or adhesive bonding. While this requires specialized equipment, it eliminates the need for multiple separate components (seals, fasteners), reducing overall part count and simplifying the assembly process despite the specialized welding step.
Solution Approach 2:
The connection method transitions from mechanical (reversible) to material-fit (irreversible), changing the fundamental parameter of joint reversibility. This parameter change enables hermetic sealing and eliminates seal ageing, while the thermoplastic material properties allow for efficient ultrasonic welding that can be integrated into automated manufacturing lines.
3Reliability
If the terminal box is hermetically sealed, then service life of electronics is extended, but repairability and component replacement become difficult
Solution Approach 1:
The terminal box is designed as separable parts (housing and cover) connected by material-fit methods. While the connection is hermetic and irreversible, the segmentation allows the entire terminal box assembly to be replaced as a module, maintaining repairability at the system level while protecting internal electronics from environmental damage.
Solution Approach 2:
The terminal box is designed with built-in mounting features and cable access points that are established during manufacturing. This preliminary action ensures that future maintenance or replacement can be performed by simply disconnecting cables and removing the terminal box as a unit, without requiring disassembly of the hermetic seal itself.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances the service life of motor control components, reduces manufacturing costs, eliminates electrical shock risks, and simplifies assembly and maintenance by providing a reliable, toolless connection and hermetic sealing, suitable for harsh environments.
Implementation Method 1
laser welding for assembly
Data Source
AI summary
A heating circulating pump includes a pump housing (1) containing a pump impeller driven by an electric motor. The stator thereof is arranged in a motor housing (8) connected to the pump housing (1). A terminal box (12) is arranged on the motor housing (8), for electrically connecting the motor winding and for receiving electrical and/or electronic components of the motor control system. The terminal box (12) includes at least two parts that are bonded to each other, and the terminal box (12) is designed such that it is sealed from the motor and from the surrounding environment.