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In harsh working conditions with frequent vibration and high pressure pulses, such as mine crushing, large agricultural machinery, heavy construction equipment and stamping machines, conventional couplers often fail to deliver reliable performance—loosening, leakage and fatigue fracture become persistent pain points for equipment operation.
Shanghai Kuaishi Fluid Technology Ltd. has long specialized in hydraulic quick couplers. Its RK/KL series features four core superior performances: 42 MPa high pressure resistance, strong anti-vibration capacity, resistance to high-frequency pressure pulses, and connectability under residual pipeline pressure. Additionally, it boasts differentiated advantages including ultra-low flat-face leakage and thread structure that eliminates Brinell effect. Fully tested against more than ten stringent items of ISO 18869 international standard, the series delivers long-term stable, low-maintenance rapid hydraulic connection solutions for heavy industry, mining and industrial hydraulic systems through verified actual performance.
Vibration is ubiquitous in industrial sites—roaring construction machinery, impacts of stamping equipment, bumps of transport vehicles, and more. Continuous vibration will gradually loosen ordinary couplers and cause seal failure. The root cause lies in tiny relative rotation of threaded connections triggered by vibration. As pre-tightening force decays over time, sealing gaps expand and persistent oil seepage occurs.
The RK/KL series addresses this pain point with an anti-vibration limit pin, which restricts thread rotation and fundamentally prevents loosening caused by vibration. Even if equipment operates under sustained resonance and intense bumping for long hours, the thread engagement state remains stable without decaying sealing preload, structurally solving the problem of vibration-induced oil leakage and adapting to all-weather field heavy-duty operations. To verify its reliability, the product has passed rigorous durability tests: under repeated vibration and connect-disconnect cycles simulating real working conditions, the RK/KL series maintains consistent sealing performance at all times.
Conventional ball-type quick couplers rely on steel balls for locking. Under long-term high-pressure pulse separation force, lateral force and tubing torque, steel balls repeatedly extrude the male coupling groove. Local stress far exceeds the yield strength of the base material, forming irreversible indentations—commonly known as the Brinell effect in the hydraulic industry. Once indentations accumulate to a certain extent, failures such as coupler jamming, clearance oil leakage and fatigue cracking will occur.
The RK/KL series adopts full thread engagement locking. Axial load is evenly distributed across the entire thread flank, and large-area surface contact greatly reduces unit contact pressure. Without point extrusion structure of steel balls, the design fundamentally eliminates conditions that generate Brinell indentations, drastically extending coupler service life and suiting working conditions with long-term alternating high-pressure pulses.
The product adopts a standard flat-face sealing valve assembly. The mating surfaces of male and female couplers are fully flush. When connecting, internal valve spools open only after wiping impurities off contact surfaces; during disconnection, dual valves close simultaneously to cut off fluid in pipelines. The leakage volume per single disassembly and separation is less than 0.015 cc, with nearly no residual oil dripping.
Advantages:
1. Significantly reduced on-site oil contamination and hydraulic oil consumption.
2. Block dust, mud and water from entering pipelines to avoid hydraulic element abrasion caused by contaminated oil, improving the cleanliness of the entire hydraulic system.
Shanghai Kuaisi has built a standardized fluid testing laboratory. The RK/KL series strictly complies with ISO 18869 international test specifications for quick couplers and completes a full set of more than ten performance verifications. All test indicators outperform internal corporate standards, and a complete test report is issued for every production batch:
1. High-frequency pressure pulse test: Simulate alternating pressure shocks of real equipment. After 100,000 continuous pulse cycles, couplers show no deformation, flaring, leakage or thread looseness, perfectly adapting to high-pulse working conditions including crushing, stamping and heavy-duty agricultural machinery.
2. High & low pressure leakage test: Multi-gradient pressure tightness inspection under both connected and disconnected states to control micro-leakage performance.
3.Vacuum test: Verify pipeline vacuum retention capacity after disconnection to prevent cavitation and vibration noise caused by air intake.
4. Air entrainment test: Control air intake during assembly and disassembly to protect precision hydraulic components.
5. Fluid loss test: Quantify residual oil during disassembly for low-loss and environment-friendly operation.
6. Pressure drop (∆P) test: Optimized flow cross-section reduces pipeline pressure loss and improves system energy efficiency.
7. Static pressure resistance test: Zero leakage under standby pressure.
8. High-low temperature cycling test: Cover low-temperature startup in field minus-zero environments and continuous high-temperature operation in summer with no seal hardening or leakage.
9. Full-cycle durability plug-in test: Locking and sealing performance remains undegraded after thousands of repeated assembly and disassembly cycles.
Additional verifications such as connection torque, over-tightening resistance and corrosion resistance are also conducted, and multiple closed-loop tests ensure long-term stable operation of products.
Shanghai Kuaisi RK/KL series threaded flat-face quick couplers are suitable for heavy-duty high-pressure scenarios across multiple industries:
1. Construction Machinery: Rotary drilling rigs, excavator breakers, loaders, mine tunneling equipment, road rollers, heavy-duty construction vehicles, etc.
2. Agricultural Equipment: Large combine harvesters, heavy soil preparation agricultural machinery, high-pressure hydraulic supporting implements, etc.
3. Industrial Equipment: Hydraulic stamping machine tools, industrial high-pressure hydraulic power stations, etc.
4. Special Fluid Equipment: High-pressure mobile hydraulic equipment, rapid connection systems for field heavy-duty hydraulic pipelines, etc.
