Variable-Speed Compressor Motor for Medical Shockwave Apparatus

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Solution Overview

Problem

Conventional shockwave apparatuses with pneumatic drives have inefficiencies due to steadily operating compressor motors, leading to unnecessary noise, power consumption, and larger power requirements, as they produce higher pressures than needed and waste energy when lower pressures are desired, due to the reliance on pressure reducing valves.

Innovation Solution

The shockwave apparatus features an adjustable compressor motor rotation rate, implemented with a feedback control circuit, such as a PID feedback control, and a motor run-up current limiter, allowing for precise control of gas pressure and pulse energy, reducing noise and energy consumption by eliminating the need for pressure reducing valves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a pressure reducing valve is used to control output pressure, then the desired pressure can be achieved, but the compressor must operate at higher pressure than needed causing noise and energy waste

Engineering Contradiction:
Improveoutput pressureVSAvoidenergy consumption
Core Design Contradiction:
Stress or pressureVSLoss of energy

Solution Approach 1:

The compressor motor rotation rate is made dynamically adjustable through feedback control based on the desired shockwave pressure. The system transitions from static fixed-speed operation to dynamic variable-speed operation, allowing the compressor to operate only at the necessary pressure level rather than always at maximum pressure followed by pressure reduction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A feedback control circuit is implemented that receives the desired pressure value and adjusts the compressor motor rotation rate accordingly. The control system continuously monitors the desired pressure and manipulates the motor speed to achieve the target pressure directly at the compressor output, eliminating the need for pressure reducing valves and the energy waste associated with them.

Inventive Principle:
Principle #23Feedback

2Stress or pressure

If a pressure reducing valve is used to control output pressure, then the desired pressure can be achieved, but noise is generated due to pressure difference discharge

Engineering Contradiction:
Improveoutput pressureVSAvoidnoise
Core Design Contradiction:
Stress or pressureVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts the compressor motor speed to match the desired pressure requirements in real-time. By making the compressor operation dynamic rather than static, the system avoids the noise-generating pressure reduction process that occurs with pressure reducing valves, as the compressor directly produces the required pressure without excess pressure discharge.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The feedback control circuit eliminates noise by preventing the formation of excessive pressure in the first place. By using feedback to adjust motor rotation rate according to desired pressure, the system avoids the pressure differential that would otherwise be discharged through pressure reducing valves, thereby eliminating the associated noise generation.

Inventive Principle:
Principle #23Feedback

3Stress or pressure

If the compressor is designed for maximum pressure capability, then high pressure shockwaves can be produced, but the power class and size are larger than needed for lower pressure applications

Engineering Contradiction:
Improvemaximum pressure capabilityVSAvoidcompressor size
Core Design Contradiction:
Stress or pressureVSWeight of stationary object

Solution Approach 1:

The compressor system is designed with variable-speed capability, allowing a single compressor unit to adapt its output to match the required pressure level. This dynamic operation enables the use of a smaller, more compact compressor that can be operated at higher speeds when maximum pressure is needed, rather than requiring an oversized compressor designed for continuous maximum pressure operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operating parameters (motor rotation rate) of the compressor to match the required pressure output. By allowing parameter changes in motor speed, the same compressor can serve multiple pressure requirements without needing to be oversized for maximum pressure applications, thereby reducing the overall size and power class of the compressor unit.

Inventive Principle:
Principle #35Parameter changes

4Stress or pressure

If the compressor motor rotation rate is adjustable, then precise pressure control is achieved, but the device complexity increases

Engineering Contradiction:
Improvepressure control precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

A feedback control circuit is implemented that receives the desired pressure value and automatically adjusts the compressor motor rotation rate. This feedback mechanism provides precise pressure control by continuously comparing the desired pressure with actual operating conditions and making real-time adjustments, achieving accurate pressure control without requiring complex manual adjustment mechanisms.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical pressure control mechanisms (such as pressure reducing valves and manual adjustment systems) with an electronic feedback control system that manipulates motor rotation rate. This substitution of mechanical control with electronic control achieves precise pressure control while actually simplifying the overall device structure by eliminating mechanical pressure reduction components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This solution enables more efficient operation by adjusting compressor motor speed to match desired pressures, reducing noise and energy waste, and allowing for more precise control of shockwave intensity, improving the overall efficiency and usability of the apparatus.

Implementation Method 1

A compressor compresses for example air as a pressure gas to be used for accelerating the projectile in a guiding tube

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

A compressor compresses for example air as a pressure gas to be used for accelerating the projectile in a guiding tube

Methodology Applied
Scientific EffectGas pressure acceleration: Pressure Gradient

Data Source

PatentEP2381864B1Shockwave apparatus having a pneumatic drive
Publication Date: 2012.09.05 STORZ MEDICAL
  • EP2381864B1 patent drawingFigure 1
  • EP2381864B1 patent drawingFigure 2

AI summary

The invention relates to a shockwave apparatus for treating a human or animal body, the pneumatic drive of which comprises a motor-driven compressor. According to the invention, the rotation rate of the motor is controlled in order to set a certain compressor pressure.