Low-Flow Proportional Metering Pump With Peristaltic Dosing
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Solution Overview
Problem
Conventional proportional dosing pumps struggle to deliver low doses, such as less than 300 ppm or tens of ppm, due to insufficient sizing of suction devices, resulting in excessive dosages.
Innovation Solution
The use of displacement pumps, particularly peristaltic pumps, which operate at low speeds and have a flow rate proportional to the speed of actuation, combined with a motion converter to transform reciprocating translational motion into rotational motion, allowing precise dosing of additives into a main liquid stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional suction devices are used in proportional dosing pumps, then the pump structure is simple, but the dosing precision deteriorates at low doses (less than 300 ppm)
Solution Approach 1:
The pump is divided into two independent pumping systems: a main liquid pump and an additive displacement pump. Each pump handles its respective fluid independently, allowing precise control of additive dosing without affecting the main liquid flow. The motion converter segments the motion transmission path, converting reciprocating motion to rotational motion specifically for the additive pump.
Solution Approach 2:
A motion converter is introduced as an intermediary mechanism between the reciprocating pump and the additive displacement pump. This converter transforms the reciprocating translational motion into rotational motion, enabling precise control of the additive pump while maintaining the simplicity of the original reciprocating pump structure.
2Manufacturing precision
If conventional reciprocating pump is used, then the device operates at high speed, but the flow rate control precision deteriorates due to discharge pressure impact
Solution Approach 1:
The additive dosing mechanism is replaced with a displacement pump that uses positive displacement principles rather than pressure-driven flow. This substitution ensures that the additive flow rate is determined by the pump's geometric displacement and rotational speed, not by discharge pressure variations, achieving precise flow control.
Solution Approach 2:
The system changes the operating parameters of the additive pump by controlling its rotational speed through the motion converter. By varying the rotational speed parameter, the flow rate can be precisely controlled independent of pressure conditions, allowing accurate dosing at different operating conditions.
3Adaptability or versatility
If suction device size is increased to improve dosing capability, then the dosing range expands, but the dosing precision for low doses deteriorates
Solution Approach 1:
The dosing system is segmented into two independent channels: main liquid delivery and additive dosing. The additive channel uses a separately controlled displacement pump that can be precisely sized for low-dose applications, while the main liquid pump handles the bulk flow. This segmentation allows each component to be optimized for its specific function.
Solution Approach 2:
The additive displacement pump provides dynamic control of dosing rates through variable rotational speed via the motion converter. This dynamic capability allows the system to adapt to different dosing requirements while maintaining precision across the entire dosing range, from very low doses to higher doses.
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 accurate and efficient delivery of low doses by minimizing the impact of discharge pressure on flow rate, ensuring precise mixing of additives with the main liquid.
Implementation Method 1
pumps of the peristaltic type, that is, pumps able to suck and discharge a liquid when operating at low speed
Implementation Method 2
a motion converter provided to transform the reciprocating translational motion of the member into a rotational motion
Data Source
AI summary
A proportional metering method and its associated pump, which includes: a hydraulic machine enclosing a member suitable for performing an alternative movement, supply to the machine at the inlet triggering an alternative translational movement by the member, a volumetric pump, provided with a rotational axis, an inlet intended to be placed in fluid communication with an additive tank, and an outlet in fluid communication with the outlet of the machine, a movement converter for converting the alternative translational movement of the member into a rotational movement, the rotational movement being transmitted to the rotational axis of the volumetric pump, such that supplying the machine operates the volumetric pump, which thus supplies the outlet of the hydraulic machine with additive.