Compensated Flow Control Valve for Constant Hydraulic Flow
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Solution Overview
Problem
Existing flow control valves for hydraulic systems fail to maintain a constant fluid flow rate in response to pressure variations, requiring additional valves to compensate, which complicates and increases the system's bulk and cost.
Innovation Solution
A flow control valve design with a shutter body, needle shutter, movable core, and springs that automatically adjust to pressure changes, using an electric coil to maintain a consistent flow rate by compensating for pressure fluctuations through the interaction of multiple springs and a service chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional flow control valve with a needle shutter and movable core is used, then the flow rate can be regulated by varying the magnetic attraction on the movable core, but the flow rate varies with inlet pressure changes, requiring additional compensation valves
Solution Approach 1:
A service chamber is introduced as an intermediary element between the movable core and the needle shutter. This service chamber receives inlet fluid and transmits its pressure to act on the needle shutter, enabling indirect control of the shutter body position. The service chamber acts as a mediator that converts pressure variations into positional adjustments, resolving the contradiction between flow regulation capability and flow constancy under varying pressure conditions.
Solution Approach 2:
The system implements automatic feedback control where pressure variations in the service chamber directly influence the needle shutter position. When inlet pressure increases, the service chamber pressure increases, automatically adjusting the needle shutter to maintain constant flow rate. This feedback mechanism eliminates the need for external compensation valves while ensuring reliable flow rate constancy.
2Reliability
If a second compensation valve is added to maintain constant flow rate, then flow rate constancy is improved, but the circuit complexity and system bulk increase
Solution Approach 1:
The compensation function is merged into the existing flow control valve structure. The service chamber, needle shutter, and spring mechanism are integrated within the valve body, combining flow regulation and pressure compensation functions in a single device. This eliminates the need for separate compensation valves, reducing circuit complexity while maintaining flow rate constancy.
Solution Approach 2:
The flow control valve is designed with multi-functionality, serving both as a flow regulation device and a pressure compensation device. The service chamber and needle shutter mechanism enable the valve to automatically compensate for pressure variations while controlling flow rate, making it a universal component that replaces multiple specialized valves.
3Ease of operation
If a second shutoff valve is added to completely stop oil flow, then flow control capability is improved, but the system bulk and cost increase
Solution Approach 1:
The valve employs dynamic control through the needle shutter mechanism that can adjust the orifice opening continuously. The service chamber pressure dynamically adjusts the needle shutter position, enabling the valve to achieve complete flow shutdown when needed, while maintaining the ability to regulate flow at various intermediate rates. This dynamic capability replaces the need for separate shutoff valves.
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 valve effectively maintains a constant fluid flow rate despite pressure variations, simplifying the system and reducing the need for additional compensation valves, while ensuring precise control over fluid flow.
Implementation Method 1
which can be selectively attracted to move in the opposite direction by the electromagnetic field generated by an electric actuating coil
Implementation Method 2
The movable core is coupled to the needle shutter and to one or more springs, so as to be pushed by these latter in the direction towards the shutter body
Implementation Method 3
due to an increase in pressure in the service chamber
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A flow control valve (100) is described, comprising: a valve body (105), a shutter body (185) slidingly coupled to the valve body (105), an orifice (255) made in the shutter body (185), a needle shutter (265) sliding from a closing position of said orifice (255) towards various opening positions of said orifice (255), a movable core (290) sliding in the same direction as the needle shutter (265) and adapted to slidingly drag one or more first springs (330) adapted to push the movable core (290) and/or the needle shutter (265) along the sliding direction towards the shutter body (185), an electric coil (325) adapted to be electrically powered to operate the movable core (290) in the direction away from the shutter body (185), in contrast with the action of each of said first springs (330), and at least a second spring (355), operatively interposed between said movable core (290) and said needle shutter (265) which while opposing itself with an elastic reaction force thereof, allows the needle shutter (265) to perform a relative movement with respect to the movable core (290), along the sliding direction and in the direction towards the shutter body (185), due to a pressure increase in the service chamber (155).