Hydac SBO Diaphragm Accumulator | SBO140 SBO200 SBO210 Hydro-Accumulator

The SBO Series high-pressure diaphragm hydro-accumulators manufactured by Chengyuan Hydraulic are ultra-compact fluid power storage and pressure regulation modules fully engineered to match global Hydac industrial benchmarks. Optimized to deliver instant fluid compensation, high-frequency shock suppression, and emergency auxiliary pilot energy, this heavy-duty series covers central operational formats including the high-delivery SBO140-1.4E1/112U-140AB, the compact high-pressure SB0210-0.75E1/112A9-210AK, and the standard industrial SBO200-1E1/112U-200AB. Constructed from carbon steel two-shell halves joined via continuous deep-penetration thermal welding, these vessels feature a flexible, high-stiffness polymer diaphragm dividing the internal gas chamber from the fluid section. Every singular SBO accumulator undergoes 100% water-jacket hydrostatic burst safety verification and extended nitrogen gas-tight retention checks under peak engineering constraints to match official standards, delivering proven 100% original-place interchangeable compatibility.

Technical Specifications 

• Core Product Series: Hydac SBO Series Compact Diaphragm Hydraulic Accumulators

• Model Configurations Supported: SBO140-1.4E1/112U-140AB / SB0210-0.75E1/112A9-210AK / SBO200-1E1/112U-200AB

• Nominal Volumetric Capacities:

  • SBO210-0.75 Profile: Nominal gas volume capacity of 0.75 Liters (0.75 L)

  • SBO200-1 Profile: Nominal gas volume capacity of 1.0 Liter (1.0 L)

  • SBO140-1.4 Profile: Nominal gas volume capacity of 1.4 Liters (1.4 L)

• Maximum Allowable Working Pressure Coding:

  • SBO140 Framework: Maximum operational envelope of 140 bar (14 MPa / 2030 psi)

  • SBO200 Framework: Maximum operational envelope of 200 bar (20 MPa / 2900 psi)

  • SB0210 Framework: Maximum operational envelope of 210 bar (21 MPa / 3045 psi)

• Diaphragm Elastomer Compound Configuration (112): Premium NBR (Nitrile) or thermal-stabilized ECO compound material, minimizing flex fatigue and authorizing extensive fluid temperatures from -10°C to +80°C

• Gas Port Charge Interface (E1): Standard M28×1.5 Hydac gas valve connection profile (or permanent unchargeable factory-sealed plug design, aligned per specific ordering codes)

• Fluid Port Thread Configurations (U / A9): Standard internal BSP/G-type female threads (e.g., G 1/2 or G 3/4) integrated with a lower mechanical anti-extrusion plate

Key Technical Advantages:

• Monoblock Hemispherical Steel Welding with Low Thermal Distortion: The outer steel vessel is formed by high-tensile cold-pressed carbon steel shells. These halves are integrated with the central diaphragm locking gland using fully automated electron-beam or precision friction welding. The continuous weld seam features excellent grain consolidation, surviving millions of extreme high-frequency pressure expansion/contraction cycles without micro-void leakage or fatigue cracking.

• Near-Zero Mechanical Mass Inertia for Millisecond ($\text{ms}$) Shock Mitigation: Unlike heavy piston accumulators that suffer from frictional lag, a diaphragm accumulator relies on a lightweight polymer membrane with virtually no mechanical inertia. This configuration allows the vessel to immediately catch and flatten micro-pulsations, acoustic frequencies, and sudden directional valve hammer spikes inside high-response pilot control lines.

• Low Gas Permeability Compound Formulation: The internal rubber layer is synthesized with highly cross-linked polymer chain structures to eliminate micro-gaseous migration. This design limits nitrogen ($N_2$) gas molecule transmission into the fluid lines, maintaining consistent precharge values far longer than standard options. A specialized clamping rim on the outer radius creates an absolute static gas seal under maximum shell torque.

• Integrated Anti-Extrusion Mechanical Protection: When downstream pressure drops or drops to zero, expanding internal gas forces the diaphragm down into the fluid discharge orifice. To prevent damage, a solid vulcanized metal disc shield at the center of the membrane blocks the port. This limits the membrane’s travel and stops the rubber from extruding into the pipeline under differential pressure.

Application Areas:

• Mobile Equipment Pilot & Braking Arrays: Pressure preservation modules for main pilot manifolds in tracking excavators, and emergency auxiliary reservoirs for wet multi-disc wheel brake loops in heavy wheel loaders.

• Specialty Vehicle Ride Control & Suspension Shock Loops: Hydraulic dampening accumulators mounted to outrigger stabilization systems, and nitrogen-charged ride cushions for material handling forklifts.

• Industrial Automation Machine Tool HPUs: Long-term pressure compensation, thermal volume expansion damping, and hydraulic clamp force holding for fast-cycling metal stamps and shears.

Expert Maintenance Tips:

• Mandatory Nitrogen ($N_2$) Purity Limits and Explosion Safeguards: The gas chamber must be precharged exclusively with dry, industrial-grade Nitrogen gas ($N_2$) matching a minimum purity of $\ge 99.99\%$—never charge with oxygen, shop air, or flammable compressed gases, which will trigger thermal explosions under high-frequency hydraulic cycling. Precharge levels ($P_0$) must be configured explicitly between 60% and 80% of the normal low-limit system pressure.

• Enforce Absolute Depressurization Prior to Component Disconnection: Before wrenching any fluid lines, fitting adaptors, or mounting seals connected to the SBO body, the trapped fluid pressure on the hydraulic side must be fully evacuated back to the main reservoir through a dedicated safety release block until all inline pressure gauges drop to zero. Never service a system under hydraulic load.

• Enforce Slow-Feed Charging Profiles to Prevent Diaphragm Tearing: When administering nitrogen gas via a standard charging apparatus (such as a Hydac FPU-1 kit), open the nitrogen bottle regulator slowly to feed gas in a controlled stream—never blast high-pressure gas into the shell instantly. Sudden pressure shocks cause rapid thermodynamic cooling and localized stress, which can wrinkle or tear the diaphragm before it unrolls smoothly.