Rexroth Z2S6 & Z2SRK6 Check Valve Z2S6-1-6X R900347495

The industrial-grade Z2S6 and Z2SRK6 Series Sandwich Plate Check Valves (highlighting highly requested global B2B reference configurations Z2S6-1-6X/, original ordering code R900347495, and the high-temperature variant Z2SRK 6-1-11/V/60, ordering code R900564519), engineered by Chengyuan Hydraulic, are high-performance pilot-operated check valves designed for absolute actuator isolation and load-holding safety. Featuring a standard sandwich/modular plate design in Size 6 (Cetop 3 / D03), the mounting interface aligns perfectly with ISO 4401-03-02-0-05 and NFPA T3.5.1 R2-D03 international standardized patterns.

Chengyuan’s Z2S6 and Z2SRK6 series provide 100% direct drop-in interchangeability with premium industry standards (such as Bosch Rexroth 6X and 1X series manual specifications). These modular units stack seamlessly beneath standard directional spool valves (such as the 4WE6 series) without requiring custom block manifolds or secondary external piping. This design allows mechanical engineering firms and fluid power distributors to easily integrate or service equipment while lowering supply chain costs.

Serving as a primary safety mechanism, pilot-operated sandwich check valves must withstand high static holding pressures and sudden flow spikes without micro-leakage. Any internal fluid bypass can cause hydraulic cylinders to drift, outriggers to retract, or heavy loads to drop unexpectedly. To ensure reliable performance under these conditions, 100% of Chengyuan’s Z2S series valves undergo 100% rigorous dynamic simulation test bench validation at full pressure. Each unit is tested at a maximum continuous pressure of 31.5 MPa to confirm zero-leakage closure and consistent pilot piston activation under harsh field operations.

Technical Specifications

• Product Classification: Pilot-Operated Sandwich Plate Check Valve

• Nominal Valve Size: Size 6 (Cetop 3 / ISO 03 / D03 Interface Footprint)

• Cross-Reference Ordering Material Codes:

  • Z2S6-1-6X/ Standard Line Equivalence: R900347495

  • Z2SRK 6-1-11/V/60 Specialized Line Equivalence: R900564519

• Maximum Permissible Operating Pressure: 31.5 MPa (315 bar / 4568 psi)

• Maximum Flow Capacity Limit: Up to 60 L/min (15.8 gpm)

• Pilot Piston Area Area Ratio: $A_{\text{Pilot Piston}} / A_{\text{Check Poppet}} = 3.2 : 1$ (Ensuring steady, predictable opening when pilot pressure reaches approximately 1/3 of the main circuit pressure).

• Standard Cracking Pressure Options: 0.15 MPa (1.5 bar) as standard; alternative 0.3 MPa (3 bar) or 0.7 MPa (7 bar) heavy spring ratings available upon request.

• Fluid Media Compatibility: Petroleum-based mineral oils (HL, HLP) and eco-friendly synthetic esters / fire-resistant fluids (HFD-R, when paired with FKM seals).

• Sealing Configuration & Thermal Ranges:

  • Z2S6-1-6X Standard: Nitrile Rubber Seals (NBR), rated for $-30^{\circ}\text{C}$ to $+80^{\circ}\text{C}$

  • Z2SRK6-1-11/V/60: Premium Fluorocarbon Seals (FKM/Viton, designated by “V”), rated for $-20^{\circ}\text{C}$ to $+120^{\circ}\text{C}$

• Isolating Channel Designation: Code “-1” denotes that both service ports A and B feature independent pilot-operated poppets, delivering dual-channel absolute blocking capability.

Key Technical Advantages

• Micro-Honed Alloy Steel Poppets with Spherical Line-Contact: The internal check poppet and seating rings are machined from specialized high-alloy steel and case-hardened to $\ge HRC 60$ via vacuum induction quenching. The poppet profile undergoes advanced spherical line-contact grinding to achieve absolute zero-leakage drop insulation at full 31.5 MPa pressure, preventing actuator drift.

• Gas-Nitrided Low-Friction Pilot Control Piston: The internal pilot control spool, responsible for mechanically unseating the poppet during reverse flow, features a precision gas-nitrided finish. This surface treatment ensures high wear resistance and an exceptionally low friction coefficient, eliminating pilot stick-slip and ensuring smooth pressure decompression.

• CFD-Optimized Low Pressure-Drop Cast Housing: The main valve body is cast from high-tensile ductile iron using automated molding techniques. Internal core channels for ports A, B, P, and T are optimized using Computational Fluid Dynamics (CFD) to maximize effective cross-sectional flow areas. This reduces local pressure drop by 18% at a full 60 L/min flow rate, mitigating system heat generation.

• Fatigue-Resistant Stainless Steel Bias Springs: Poppet return springs are wound from high-grade alloy spring wire and shot-peened to eliminate residual tensile stress. Designed to withstand continuous high-frequency cycling (exceeding 3 Hz), these springs maintain uniform tension over an operational service life exceeding 10 million cycles.

Application Areas

The Z2S6 and Z2SRK6 series modular check valves are vital safety components integrated into compact hydraulic manifolds across various industries:

• Metal Forming & Stamping Machinery: Maintaining clamping pressure in die assemblies and securing overhead main rams against gravity-induced drifting.

• Mobile Outrigger & Stabilization Circuits: Serving as reliable terminal load-holding locks on hydraulic stabilizer jacks for mobile cranes and aerial boom lifts.

• Plastic Injection Molding Equipment: Providing long-term pressure holding within the core-pulling, injection-stroke, and mold-clamping manifold blocks to ensure tight manufacturing tolerances.

Expert Maintenance Tips

• Apply the Specified 11 Nm Torque Limit Uniformly During Stack Mounting: When tightening the M5 high-tensile tie-rods, always use a calibrated torque wrench and follow a diagonal, progressive sequence. Insufficient torque can cause O-ring extrusion and external weeping, while exceeding 12 Nm can induce micro-warping of the ductile iron housing, causing the internal pilot piston to bind or fail to return.

• Pay Close Attention to the Special Seals of the Z2SRK Variant During Replacement: The Z2SRK 6-1-11/V/60 contains a “V” suffix indicating Viton (FKM) sealing matrices tailored for high-temperature zones or synthetic HFD-R fluids. Installing standard NBR versions in these demanding environments can lead to rapid seal swelling or thermal cracking within weeks, resulting in severe cross-port fluid bypass.

• Maintain System Fluid Cleanliness at ISO 4406 20/18/15 or Better with Dedicated Off-line Filtration: Because the clearance boundaries between the control piston and the honed bore are measured in microns, micro-shavings or oxidized varnish can easily become trapped on the valve seat. This prevents complete poppet closure, causing gradual loss of pressure and cylinder drift.