Variable Flow Pump Swashplate Actuation for Pressure Relief
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Solution Overview
Problem
Conventional pumps, especially those used in pressure washers, face stress and reduced lifespan due to continuous operation against closed valves, which leads to increased wear and friction, as they try to maintain high pressure demands intermittently.
Innovation Solution
A variable flow pump design featuring a swashplate coupled with a driveshaft, allowing the swashplate to tilt between angles to adjust piston pump displacement based on downstream backpressure, utilizing an actuator assembly with a biasing member to manage the swashplate's position and reduce friction through independent rotation of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pump operates continuously to maintain high pressure, then pressure demand is satisfied, but wear and stress on the pump increases
Solution Approach 1:
The pump system dynamically adjusts the swashplate angle based on downstream backpressure conditions. When backpressure is high (valve closed), the swashplate angle reduces to minimize piston displacement and flow rate. When backpressure is low (valve open), the angle increases to maximize flow rate. This dynamic adaptation allows the pump to respond to changing system conditions, maintaining reliability by reducing stress during valve closure while preserving productivity during valve opening.
Solution Approach 2:
The system employs a feedback mechanism where downstream backpressure is sensed and used to control the swashplate actuator. The backpressure signal feeds back to the actuator assembly, which adjusts the swashplate angle accordingly. This closed-loop control ensures the pump operates efficiently under varying conditions, extending lifespan by reducing unnecessary pumping against closed valves while maintaining high pressure delivery when needed.
2Adaptability or versatility
If the swashplate is held at a fixed angle, then the pump structure is simple, but the flow rate cannot be adjusted based on pressure demands
Solution Approach 1:
The swashplate actuator assembly is self-regulating, using downstream backpressure itself as the actuating force. The backpressure directly influences the actuator piston position, which in turn controls the swashplate angle. This self-service mechanism eliminates the need for external sensors, controllers, or power sources, achieving flow rate adaptability while keeping the device complexity relatively low. The system essentially uses its own operating conditions to control its performance.
Solution Approach 2:
The actuator assembly utilizes hydraulic principles where downstream backpressure is transmitted to the actuator piston through fluid pressure. This pneumatic/hydraulic transmission converts the backpressure force into mechanical motion that adjusts the swashplate angle. This approach provides smooth, continuous flow rate adjustment without complex mechanical linkages or electronic control systems.
3Stress or pressure
If the pump operates against a closed valve, then pressure is maintained, but stress on the pump and prime mover increases
Solution Approach 1:
The system changes the operational parameters of the pump by adjusting the swashplate angle in response to downstream backpressure. When a valve closes and backpressure rises, the swashplate angle is reduced, which decreases piston displacement and flow rate. This parameter change allows the pump to maintain pressure (by continuing to pump at a reduced rate) while significantly reducing the mechanical stress and power demand on the pump and prime mover, thereby protecting component durability.
Solution Approach 2:
Instead of completely stopping the pump when a valve closes, the system applies partial action by reducing the swashplate angle to a smaller but non-zero value. This maintains a reduced level of pumping action that is sufficient to hold pressure in the system without the excessive stress of full-power operation against a closed valve. The partial action balances pressure maintenance with component 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
This design reduces wear and stress on the pump by adjusting flow rate and displacement in response to pressure demands, extending the pump's lifespan and improving efficiency by minimizing friction and wear.
Implementation Method 1
a swashplate coupled with a driveshaft for rotatably driving the swashplate. The swashplate may be movable between a first tilt angle relative to the driveshaft and a second tilt angle relative to the driveshaft. A piston pump may interact with the swashplate for being reciprocatingly driven based upon, at least in part, the tilt angle of the swashplate.
Implementation Method 2
An actuator piston may be moveable between a first position and a second position based upon, at least in part, a downstream backpressure of a fluid pumped by the piston pump.
Implementation Method 3
The actuator assembly may also include a biasing driver configured to apply a force urging the swashplate into contact with the swashplate driver.
Data Source
AI summary
In an embodiment, a variable flow pump may include a swashplate rotatably driven by a driveshaft. The swashplate may be movable between a first and second tilt angle relative to the driveshaft. A piston pump may be reciprocatingly driven by the swashplate based upon, at least in part, the tilt angle of the swashplate. An actuator piston may be moveable between a first and second position based upon, at least in part, a downstream backpressure of a fluid pumped by the piston pump. An actuator assembly may be moveable between a first and second position based upon, at least in part, the position of the actuator piston. The actuator assembly may include a swashplate driver configured urge the swashplate between the first and second tilt angles, and a biasing driver configured to apply a force urging the swashplate into contact with the swashplate driver.