Liquid Feed Pump Plunger Seal Acid-Resistant Coating
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Solution Overview
Problem
The existing liquid feed pumps are prone to corrosion and etching of the pump head due to the use of highly volatile acids, leading to leakage and decreased sealing performance, as the softer inner surface of the plunger seal wears out, allowing acid vapors to penetrate and react with the metal pump head.
Innovation Solution
A liquid feed pump with a plunger seal attachment portion coated with an acid-resistant material, such as noble metals or diamond-like carbon, to prevent corrosion and etching, ensuring the plunger seal maintains its sealing performance even when exposed to acidic liquids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the plunger seal is made of softer material to improve sealing performance, then the sealing performance is improved, but the inner circumferential surface wears out faster allowing acid penetration
Solution Approach 1:
The patent applies different material properties to different parts of the plunger seal assembly. The plunger seal itself remains soft for sealing, while the pump head's seal attachment portion is coated with a hard, acid-resistant material (diamond-like carbon or noble metal) to prevent wear and acid corrosion, creating a differentiated local quality that resolves the contradiction between soft sealing and durable acid resistance
Solution Approach 2:
The invention creates a composite structure by combining the soft plunger seal material with the hard acid-resistant coating on the pump head. This composite approach allows the system to simultaneously achieve the sealing properties of soft materials and the durability/acid resistance of hard materials, resolving the contradiction between sealing performance and service life
2Strength
If the pump head is made of metal to improve strength, then the structural strength is improved, but the metal surface is corroded by acid
Solution Approach 1:
The patent applies acid-resistant coating material (diamond-like carbon or noble metal) specifically to the seal attachment portion of the pump head where acid contact occurs, while maintaining the metal structure elsewhere for strength. This localized application provides acid resistance exactly where needed without compromising overall structural integrity
Solution Approach 2:
The acid-resistant coating acts as an intermediary layer between the metal pump head and the acidic mobile phase. This intermediate layer prevents direct contact between the acid and metal surface, eliminating corrosion while maintaining the metal's structural strength
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 acid-resistant coating on the plunger seal attachment portion effectively prevents corrosion and etching of the pump head, ensuring high accuracy and reliability of liquid feeding over an extended period, even with acidic mobile phases, thereby enhancing the longevity of the plunger and maintaining precise liquid chromatography results.
Implementation Method 1
a seal attachment portion, provided at a portion of the pump head where the plunger is inserted into the pump chamber, including a wall surface for receiving the plunger seal, the wall surface being covered by a film of an acid-resistant material
Data Source
AI summary
A recess into which a protrusion of a plunger seal is to be fitted is provided at a part of a pump head where a plunger is to be inserted into a pump chamber. The plunger seal seals the pump chamber by an outer circumferential surface of the protrusion coming into close contact with an inner circumferential surface of the recess and a surface of a flange on the side of the protrusion coming into close contact with a circumferential edge surface of the recess of the pump head due to the protrusion being fitted into the recess and being pressed by a backup ring toward the pump chamber. The inner circumferential surface of the recess of the pump head and the circumferential edge surface of the recess are covered by a film of an acid-resistant material.