Cryogenic Piston Pump Chromium Coating Wear
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Solution Overview
Problem
Cryogenic reciprocating pumps face significant wear and friction issues in high-pressure applications, particularly in the sealing and piston ring areas, due to the extreme low-temperature environment and limited material combinations suitable for cryogenic liquids.
Innovation Solution
The use of chromium-based low-friction coatings with a chromium content of >98% and a layer thickness of <0.01 mm on both the liner and pump piston, along with micro-elevations to reduce contact surfaces, addresses the wear and friction challenges without the need for piston rings, simplifying the design and maintaining high pump efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If piston rings and sealing rings are used in cryogenic reciprocating pumps, then sealing function is improved, but wear resistance deteriorates due to friction in high-pressure applications
Solution Approach 1:
The invention removes the piston ring component entirely from the pump piston design. Instead of using traditional piston rings with sealing rings that suffer from friction and wear, the patent employs a smooth-bored piston with a clearance fit to the liner, eliminating the wear-prone sealing components while maintaining acceptable sealing performance through the chromium coating system.
Solution Approach 2:
The invention changes the surface properties of both the liner and piston by applying chromium-based low-friction coatings. This parameter change in surface characteristics reduces the coefficient of friction between mating surfaces, thereby reducing wear while maintaining the necessary sealing function through controlled clearance rather than mechanical rings.
2Reliability
If traditional material combinations (stainless steel liners with bronze and PTFE piston rings) are used, then sealing performance is improved, but friction and wear increase in high-pressure cryogenic applications
Solution Approach 1:
The invention fundamentally changes the surface parameters by applying chromium-based low-friction coatings to both the liner and piston surfaces. This reduces the coefficient of friction between mating surfaces, thereby reducing wear while maintaining the necessary sealing function through controlled clearance rather than mechanical rings.
Solution Approach 2:
The invention uses composite material systems - specifically chromium-based coatings applied to stainless steel substrates - to achieve both low friction and wear resistance. The chromium coating provides a low-friction surface that reduces adhesive wear, while the stainless steel substrate provides structural integrity and corrosion resistance in the cryogenic environment.
3Duration of action of stationary object
If hard chrome coatings are applied to piston rings, then wear resistance is improved, but adhesion problems occur in cryogenic conditions
Solution Approach 1:
The invention removes the piston ring component entirely from the pump piston design. Instead of using traditional piston rings with sealing rings that suffer from friction and wear, the patent employs a smooth-bored piston with a clearance fit to the liner, eliminating the wear-prone sealing components while maintaining acceptable sealing performance through the chromium coating system.
Solution Approach 2:
The invention applies the same chromium-based low-friction coating material to both the liner and piston surfaces, creating a homogeneous material system. This uniform coating approach ensures consistent friction and wear characteristics across the entire contact interface, eliminating adhesion problems that arise from dissimilar material combinations in cryogenic conditions.
4Reliability
If piston rings are used to maintain sealing, then sealing function is improved, but device complexity increases
Solution Approach 1:
The invention removes the piston ring component entirely from the pump piston design. Instead of using traditional piston rings with sealing rings that suffer from friction and wear, the patent employs a smooth-bored piston with a clearance fit to the liner, eliminating the wear-prone sealing components while maintaining acceptable sealing performance through the chromium coating system.
Solution Approach 2:
The invention merges the sealing function into the basic piston- liner interface itself, rather than requiring separate piston ring components. The chromium-coated piston surface working against the chromium-coated liner with controlled clearance provides sealing, combining the structural piston with the sealing function and eliminating the need for additional piston ring assemblies.
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
This solution provides a low-wear, low-friction material combination that enhances the operational efficiency and service life of cryogenic reciprocating pumps by minimizing wear and adhesion issues, even in lubrication-free conditions, while maintaining high pump efficiency and simplifying maintenance.
Implementation Method 1
the liner (2) has a chromium-based low-friction inner coating at least in an area close to the cylinder head and the pump piston (4) has no piston ring and has a chromium-based low-friction outer coating at least in the liner area
Implementation Method 2
along with micro-elevations to reduce contact surfaces
Data Source
AI summary
The utility model provides a reciprocating piston pump for low temperature fluid, has pump cylinder (1), and the pump cylinder includes cylinder liner (2) and cylinder end room (3). Pump piston (4) are guided on linear movement ground in cylinder liner (2) to increase / reduce from this cylinder end room (3). Admission valve (5) set up in the entering region of cylinder end room (3), and dump valve (6) set up in the discharge area of cylinder end room (3) inside the country. For this reason, pump piston (4) are constructed to be done, carries out reciprocating motion in order to arouse the pump sending process in cylinder liner (2). Cylinder liner (2) have at least coating in the low fricative chromium base in near the region the cylinder end, and pump piston (4) be do not have a piston ring and have the fricative chromium base of hanging down at least in the cylinder liner region outside the coating.