Peristaltic Pump Pressing Surface Curvature Reduces Pulsations
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Solution Overview
Problem
Existing peristaltic pumps experience significant pressure fluctuations or pulsations due to abrupt speed changes at the transitions between the infeed, intermediate, and outfeed parts, leading to undesirable effects such as reduced dispensing accuracy, hose material fatigue, and reactive forces on connected conduits.
Innovation Solution
The design of the peristaltic pump features a pressing surface with an infeed part, an intermediate part, and an outfeed part, where the length of these parts is adjusted to be between one and twice the distance between the pressing elements, ensuring a continuous first derivative of the distance variation, thereby reducing pulsations. This design can be adapted to achieve minimal or controlled pulsations based on specific requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pressing elements move rapidly along the hose with short distance between them, then the pump productivity increases, but strong pressure fluctuations and pulsations occur at the inlet and outlet sides
Solution Approach 1:
The pressing surface is designed with curved transition zones (infeed part and outfeed part) instead of sharp corners. The infeed part has a distance that decreases from a first value to a second value, and the outfeed part has a distance that increases from the second value to the first value, creating smooth curved transitions that gradually compress and decompress the hose, thereby reducing pulsations while maintaining productivity
Solution Approach 2:
The patent optimizes the geometric parameters of the pressing surface, specifically setting the length of the infeed part and outfeed part to be between 0.5 to 2 times the distance between pressing elements. This parameter optimization ensures smooth hose deformation and minimizes pressure fluctuations while maintaining efficient medium transport
2Speed
If the hose is rapidly compressed and decompressed, then the medium flow speed increases, but material fatigue occurs reducing the hose lifespan
Solution Approach 1:
The curved infeed and outfeed parts of the pressing surface create gradual compression and decompression zones, avoiding sudden stress changes on the hose material. This smooth transition reduces material fatigue and extends hose lifespan while maintaining efficient medium flow speed
3Device complexity
If the pressing elements are positioned close together, then the pump size is reduced, but strong reactive forces are generated on connected conduits
Solution Approach 1:
The curved transition zones in the pressing surface design smooth out the force variations during hose compression and decompression. This reduces the amplitude of reactive forces transmitted to connected conduits while allowing the pressing elements to be positioned close together for compact pump design
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 solution significantly reduces pulsations at both the inlet and outlet sides, extending the pump's lifespan by minimizing material fatigue and reducing reactive forces, allowing for more precise metering and longer operational durability.
Implementation Method 1
After a pressing element has passed, the form of the hose is restored due to its elastic properties. Owing to this mechanism medium is drawn into the hose on the suction side.
Implementation Method 2
which pressing elements during operation press the hose part in contact with the relevant pressing element against the pressing surface while locally compressing and closing the hose part; this such that during driving of the pressing means medium is drawn in via the medium inlet and discharged under pressure via the medium outlet
Data Source
AI summary
A pump for circulating a medium comprising an elastically deformable hose against a pressing surface, and a medium inlet and a medium outlet; pressing elements that move along the hose and press the hose against a pressing surface thereby closing the hose. The pressing surface comprises an infeed part having a distance from the pressing elements that decreases from a first value when the hose is open to a second value when the hose is closed; an intermediate part having a constant distance from the pressing elements equal to the second value; and an outfeed part connected to the medium outlet. The length of the outfeed part and/or the infeed part is greater than the distance between the pressing elements as measured along the pressing surface.