Abrasive Waterjet Pressure Equaliser for Dynamic Cutting
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Solution Overview
Problem
Abrasive waterjet machining systems face limitations in dynamic machining due to time delays in valve actuation and pressure fluctuations, leading to inefficient cutting cycles and reduced lifespan of valves, making them less competitive with laser machining systems in applications requiring rapid cutting and precision.
Innovation Solution
An abrasive waterjet apparatus with a pressure fluctuation equalising device that uses a high pressure chamber and a low pressure chamber, connected by a moveable pressure equalising member, to minimize pressure fluctuations, combined with a positive displacement pump and sensor-controlled motor drive for optimized operation and reduced valve wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional valves are used to start and stop ultra high pressure water flow in abrasive waterjet machining, then the system can perform cutting operations, but the valve seats fail after about 150,000 cycles due to impact loads, high water velocities and cavitation, limiting the system's operational lifespan and dynamic capability
Solution Approach 1:
The patent removes the conventional valve component entirely from the water flow control system. Instead of using valves with seats that are susceptible to impact loads and cavitation, the system extracts this function and replaces it with a valveless design that uses a flexible hose and controlled water pressure to start and stop the jet, thereby eliminating the reliability limitation while enabling faster cutting cycles
Solution Approach 2:
The patent replaces the mechanical valve system with a hydraulic control system. Instead of using mechanical valves that open and close to control water flow, the system uses water pressure itself and a flexible hose to control the jet, substituting a mechanical control mechanism with a hydraulic one that is more reliable and faster
2Reliability
If time delays are introduced for valve actuation and abrasive flow establishment in abrasive waterjet machining, then valve wear is reduced, but cutting cycle times increase to seconds, making the system non-dynamic and less competitive with laser machining
Solution Approach 1:
The patent extracts the valve component from the system entirely, eliminating the source of time delays associated with valve actuation and abrasive flow establishment. Without valves, there are no actuation delays and no need for delay periods to clear abrasive from tubes and cutting heads, enabling continuous rapid cutting cycles
Solution Approach 2:
The patent enables continuous cutting operation without the intermittent stoppages and delays required by valve-based systems. The valveless design with flexible hose allows the waterjet to start and stop instantly, maintaining continuous useful action and enabling cutting cycle speeds comparable to laser machining
3Ease of manufacture
If conventional intensifier pumps are scaled down for fine and micro machining with low flow rates, then the pump design becomes complex and expensive, but maintaining simple scaled-down designs compromises performance
Solution Approach 1:
The patent changes the operating parameters of the pump system by eliminating the need for precise flow rate control through complex valve mechanisms. Instead, the system uses high-pressure water from a simpler pump design and controls the jet through hydraulic means, achieving both manufacturing simplicity and precise flow control
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
Enables more dynamic and efficient cutting cycles, extending valve lifespan and improving the competitiveness of abrasive waterjet systems in dynamic machining tasks by minimizing pressure fluctuations and optimizing pump operation.
Implementation Method 1
a pressure fluctuation equalising device for said circuit... In order to equalise pressure fluctuations in the waterjet fluid flow circuit, the moveable pressure equalising member is arranged to alter the volume of the high pressure chamber
Implementation Method 2
a positive displacement pump connected to the waterjet fluid flow circuit... Low flow ultra high pressure pumps are required for such apparatuses
Data Source
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AI summary
An abrasive waterjet apparatus comprising a water jet fluid flow circuit, a positive displacement pump connected to the water jet fluid flow circuit, a pressure fluctuation equalising device (24) for said circuit, and an abrasive cutting nozzle assembly. The pressure fluctuation equalising device (24) comprises a high pressure chamber (27') connected to the waterjet fluid flow circuit, a low pressure chamber (29), and a moveable pressure equalising member (20, 21) that separates said chambers. In order to equalise pressure fluctuations in the waterjet fluid flow circuit, the moveable pressure equalising member (20, 21) is arranged to alter the volume of the high pressure chamber (27' ).