Variable Opening Pressure Limiting Valve for Machine Tool Coolant Systems
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Solution Overview
Problem
Existing coolant systems for machine tools experience undesirable pressure surges when demand for coolant decreases abruptly, due to the slow response of the pump, leading to inefficiencies and increased pumping losses.
Innovation Solution
A variable opening pressure limiting valve is introduced, with its opening pressure set slightly higher than the target pressure, allowing it to suppress pressure surges by draining coolant and maintaining efficient operation with minimal increase in pumping losses, and the feedback control device adjusts this pressure dynamically to match control fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the pump responds quickly to changes in coolant demand, then pressure stability is improved, but the pump complexity and control system complexity increase
Solution Approach 1:
A limiting valve is introduced as an intermediary component between the pump and the coolant consumers. This valve actively modulates coolant flow based on pressure feedback, serving as a mediator that absorbs the complexity of rapid pressure regulation away from the pump control system, thereby maintaining pressure stability without increasing pump control complexity
Solution Approach 2:
The system employs a feedback control mechanism where pressure sensors continuously monitor the actual pressure and feed this information back to the controller, which then adjusts the limiting valve position accordingly. This closed-loop feedback enables rapid pressure stabilization responses without requiring complex pump control modifications
2Reliability
If a fixed opening pressure safety valve is used, then pressure safety is improved, but pressure surges occur when coolant demand decreases
Solution Approach 1:
The limiting valve transitions from a static fixed opening pressure design to a dynamic variable opening pressure system. The valve's opening pressure is continuously adjusted based on the target pressure and actual pressure feedback, enabling it to adapt to changing coolant demands and prevent pressure surges while maintaining safety
Solution Approach 2:
The opening pressure parameter of the limiting valve is changed from a fixed value to a variable value that dynamically tracks the target pressure. This parameter transformation allows the valve to maintain an appropriate pressure differential under varying operating conditions, preventing both pressure surges and excessive draining
3Stability of the object's composition
If the limiting valve opening pressure is set close to target pressure, then pressure surge suppression is improved, but pumping losses increase due to frequent valve opening
Solution Approach 1:
The opening pressure parameter is optimized to maintain a specific differential above the target pressure. This parameter setting balances two competing requirements: being close enough to suppress pressure surges effectively, yet high enough to prevent excessive valve opening and associated pumping losses during normal operation
Solution Approach 2:
The feedback control mechanism continuously monitors the actual pressure and adjusts the limiting valve opening pressure dynamically. This feedback ensures the valve opens only when necessary to prevent pressure surges, rather than opening frequently due to normal control fluctuations, thereby minimizing unnecessary pumping losses
4Loss of energy
If the limiting valve opening pressure is set high, then valve opening frequency is reduced and pumping losses decrease, but pressure surge suppression capability is reduced
Solution Approach 1:
Rather than using a statically high opening pressure that would reduce valve opening frequency but compromise surge suppression, the system dynamically adjusts the opening pressure to track the target pressure. This dynamic adjustment ensures the valve maintains optimal suppression capability across varying operating conditions without incurring excessive pumping losses
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 system effectively adapts to changes in coolant demand, reducing pressure surges and maintaining target pressure stability with negligible increase in pumping losses, ensuring efficient coolant delivery across varying tool demands.
Implementation Method 1
a pressure sensor for detecting an actual pressure in the coolant system
Implementation Method 2
the limiting valve having a variable opening pressure, and the feedback control device is adapted to adjust the opening pressure in accordance with the target pressure
Data Source
Figure 1
Figure 2
AI summary
A coolant system for machine tools, comprising a pump (12) for the coolant, at least one consumer (10), a pressure sensor (24) for detecting an actual pressure (Pi) in the coolant system, a feedback control device (22) acting upon the pump (12) for regulating the pressure in the coolant system to a target pressure (Ps), and a limiting valve (26) for limiting the pressure of the coolant supplied to the consumer, wherein in that the opening pressure (Plim) of the limiting valve (26) is variable and the feedback control device (22) is adapted to adjust the opening pressure in accordance with the target pressure (Ps) such that it is always a certain amount larger than the target pressure.