Rotary Joint Shielding for CT Scanner Interference
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Solution Overview
Problem
Contactless rotary joints in CT scanners face interference issues due to high power levels and increasing data rates, leading to potential data loss or link failure, particularly because of the magnetic and electric stray fields generated by rotating transformers, which affect both data transmission and mechanical components.
Innovation Solution
The implementation of shielding measures, including conducting backplanes, inner shields, and magnetic core shields, primarily using non-metallic materials for the rotary joint body to reduce electromagnetic interference, along with improved heat dissipation and thermal management, helps minimize interference and maintain data integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power level in the rotating transformer is increased to meet higher power requirements, then the power transfer capability is improved, but the electromagnetic interference to the data link increases
Solution Approach 1:
A shielding structure is introduced as an intermediary element between the rotating transformer and the data link components. This shield acts as a mediator that blocks electromagnetic fields from the transformer from interfering with the data link, allowing high power transfer while protecting sensitive data transmission components
Solution Approach 2:
The shielding structure extends in the radial direction between the transformer and data link components, creating a spatial dimension of protection. By adding this radial shielding dimension, the patent separates the electromagnetic influence paths, allowing high power operation without proportional increase in interference
2Speed
If the bandwidth of the data link is increased to achieve higher data rates, then the data transmission capability is improved, but the sensitivity to electromagnetic interference increases
Solution Approach 1:
The shielding structure serves as a protective intermediary that specifically safeguards the high-speed data link from electromagnetic interference. This allows the system to operate at higher bandwidths and data rates without proportionally increasing vulnerability to interference, as the shield blocks harmful fields before they can affect the sensitive high-speed transmission
3Adaptability or versatility
If the gap between rotating and stationary parts is increased to accommodate mechanical movement, then the mechanical adaptability is improved, but the magnetic stray field increases
Solution Approach 1:
The shielding structure acts as an intermediary that contains and directs magnetic flux within the rotating transformer. By providing this magnetic flux management layer, the system can accommodate larger mechanical gaps for gantry tilt and rotation while preventing increased stray fields, as the shield keeps magnetic flux contained within the transformer's magnetic core
4Object-affected harmful factors
If non-metallic materials are used for the rotary joint body to reduce electromagnetic interference, then the electromagnetic compatibility is improved, but the mechanical stability may be reduced
Solution Approach 1:
The patent employs a composite structure combining non-metallic rotary joint body material with metallic shielding elements. This composite approach allows the main body to be made of electrically insulating non-metallic material for reduced interference, while integrated metallic shielding components provide the necessary mechanical reinforcement and electromagnetic protection
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 proposed solution effectively reduces electromagnetic interference, enhances data transmission reliability, and extends the operational lifespan of components by minimizing corrosion and heat-related issues, even under increased power and bandwidth conditions.
Implementation Method 1
The implementation of shielding measures, including conducting backplanes, inner shields, and magnetic core shields, primarily using non-metallic materials for the rotary joint body to reduce electromagnetic interference
Implementation Method 2
Rotating transformers produce electric and magnetic stray fields. One of the objects for designing a rotating transformer is to keep the magnetic field flux within pre-determined areas
Implementation Method 3
a capacitive data link comprising of a transmission line and a transmitter
Implementation Method 4
an inductive power coupler for transferring high power levels and a high-speed data link for broadband transmission of data
Data Source
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AI summary
A contactless rotary joint has a stationary and a rotating part. Furthermore at least one of the parts has a rotary joint body made of a plastic material and holding a capacitive data link and a rotating transformer. The rotating transformer has a magnetic core for transmission of electrical power. To prevent interference of the capacitive data link by electrical and/or magnetic fields from the rotating transformer a shield is provided.