Peristaltic Pump Pre-filling for Diaphragm Dosing Accuracy
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Solution Overview
Problem
Diaphragm-driven dosing pumps face issues with highly viscous media and media that degas under ambient conditions, leading to incomplete filling of the dosing head, inaccurate dosing, and increased wear due to cavitation, which existing solutions partially address but require significant installation effort and costs.
Innovation Solution
A delivery unit incorporating a conventional diaphragm dosing pump with a peristaltic pump that precedes the feed line, ensuring continuous medium delivery to the dosing head through rollers or sliding shoes, eliminating the need for additional heating or ventilation and reducing cavitation by maintaining sufficient pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a diaphragm-driven dosing pump is used for highly viscous media, then the pump structure is simple, but the dosing head is not completely filled leading to inaccurate dosing
Solution Approach 1:
The system is divided into two functional segments: a peristaltic pump for medium transport and a diaphragm dosing pump for precise dosing. The peristaltic pump handles the challenging task of conveying highly viscous media completely, while the diaphragm pump focuses solely on precise metering, allowing each component to be optimized for its specific function.
Solution Approach 2:
The peristaltic pump acts as an intermediary device between the medium source and the dosing head. It prepares the medium by ensuring complete filling and removing gas bubbles before the medium enters the dosing pump, thereby enabling accurate dosing without modifying the diaphragm pump structure.
2Reliability
If a diaphragm-driven dosing pump is used for media that outgas, then the pump structure is simple, but cavitation occurs causing wear and tear
Solution Approach 1:
The peristaltic pump performs preliminary actions to prevent cavitation before the medium reaches the dosing pump. By maintaining continuous contact with the medium and applying gradual compression, it ensures complete filling and removes gas bubbles in advance, preventing cavitation in the dosing head and extending pump life.
Solution Approach 2:
The peristaltic pump serves as a protective intermediary that shields the diaphragm pump from harmful effects of gas-containing media. It handles the gas removal and pressure stabilization functions, allowing the diaphragm pump to operate reliably without direct exposure to cavitation-prone conditions.
3Manufacturing precision
If heating or ventilation devices are added to the dosing head, then dosing accuracy improves, but installation effort and costs increase significantly
Solution Approach 1:
The problematic functions of heating and ventilation are extracted from the dosing head and transferred to the peristaltic pump section. The peristaltic pump inherently provides gas removal through its compression mechanism and maintains pressure through continuous medium contact, eliminating the need for separate heating or ventilation devices in the dosing head.
Solution Approach 2:
The peristaltic pump performs self-service by using its own compression action to remove gas bubbles and maintain pressure. The rollers and housing work together to continuously contact and compress the medium, automatically handling gas removal without requiring external heating or ventilation equipment.
4Ease of operation
If the medium is stored geodetically above the pump, then positive inflow is ensured, but installation complexity increases
Solution Approach 1:
The gravitational mechanical system (geodetic storage above pump) is replaced with a peristaltic pump system that uses roller compression to create positive pressure. This mechanical substitution allows reliable inflow without requiring elevated storage positions or complex installation arrangements.
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 precise dosing and reduces wear by consistently providing medium under delivery pressure, eliminating cavitation and the need for additional equipment, thus improving the reliability and efficiency of dosing viscous and gaseous media.
Implementation Method 1
In a peristaltic pump, the feed line is laid more or less around a rotor, which clamps off the feed line via rollers or sliding shoes located opposite one another. By turning the rotor, the contents of the feed line are conveyed between the rollers or sliding shoes in the direction of rotation.
Data Source
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AI summary
When using metering pumps with a small delivery volume, problems can arise, particularly with highly viscous media, media that outgas under ambient conditions, or media near a critical point. Specifically, this can lead to the metering head not being completely filled, resulting in an undefined quantity of medium being dispensed. Furthermore, cavitation can occur in the metering head, leading to damage. The invention solves this problem by connecting a peristaltic pump upstream of the metering pump, which ensures uniform filling of the metering head. This combines the advantages of both pump types into a particularly advantageous delivery unit.