Hydac HYDAC SB (bladder accumulators)
HYDAC SB330, SB400, SB500, SB550 and SB600 series hydraulic bladder accumulators, with nominal volumes from 0.5 to 200 l and working pressures from 330 to 550 bar.
The SB is HYDAC's series of standard hydraulic bladder accumulators: a closed elastomer bladder filled with gas (nitrogen), inside a seamless high-strength steel pressure vessel, with an oil valve at the hydraulic connection. The HYDAC document groups the SB330, SB400, SB500, SB550 and SB600 series and the variants SB330B (bladder replaceable from the top), SB330N (flow-optimised valve, up to 25 l/s) and SB330H (high flow, up to 30 l/s). The SB600 is offered with ASME U Stamp approval, at a maximum pressure of 345 bar. The shell is standard carbon steel, with corrosion protection, or stainless steel on request, and the bladder is chosen according to the fluid: NBR, ECO, IIR or FKM.
The full code is read in the order given in the document, for example SB330 (H) – 32 A 1 / 112 U – 330 A 050: series and variant, nominal volume in litres, type of hydraulic connection, connection on the gas side, material code (112 for mineral oil), certification code (U for the European Pressure Equipment Directive, PED), permissible working pressure, connection thread and gas precharge pressure p0 at 20 °C. For a quotation, please send us the full code or a photo of the nameplate, the target pressure p0, the fluid and the country of installation; we check the code structure in the HYDAC document before issuing the quotation.
Models and codes
| Code | Note |
|---|---|
| SB330 – 4 l | working pressure 330 bar (U certification), article number 3047166 in the document table. |
| SB330 – 6 l | 330 bar (U certification), article number 3047168. |
| SB330 – 10 l | slimline version, for limited space; 330 bar (U certification), article number 3047170, effective gas volume 9.3 l. |
| SB330N – 10 l | flow-optimised oil valve, 330 bar, maximum flow 25 l/s, article number 3156632. |
| SB330H – 10 l | high-flow version, 330 bar, maximum flow 30 l/s, article number 3079081. |
| SB400 – 0.5 l | 400 bar (U certification), article number 3047163. |
| SB550 – 1…5 l | series for 550 bar, volumes from 1 to 5 l in the document table. |
| SB330 – 60…200 l | volumes of 60, 80, 100, 130, 160 and 200 l, all at 330 bar. |
Key specifications
| Series in the document | SB330, SB400, SB500, SB550, SB600; variants SB330B, SB330N, SB330H |
|---|---|
| Permissible working pressure (U certification) | 330 (SB330), 400 (SB400), 500 (SB500), 550 (SB550) bar |
| SB600 (ASME approval, code S) | 345 bar |
| Nominal volumes | 0.5 – 200 (depending on series) l |
| Working temperature, articles in the table | -10 … +80 °C |
| Bladder materials (code in the material code) | NBR (2, 5, 9), ECO (3), IIR (4), FKM (6) |
| Charging gas | nitrogen, minimum class 2.8 |
| Precharge limits | p0 ≤ 0.9 · p1; permitted ratio p2 : p0 ≤ 4 : 1 |
The HYDAC document "Bladder accumulators, Standard design" (EN 3.201.32/05.24) is current, with no mention of withdrawal from the range.
Frequently asked questions
How do I read "SB330-20A1/112U-330A125"?
SB330 is the series, 20 the volume in litres, A the type of hydraulic connection (thread with internal sealing surface), 1 the standard design on the gas side, 112 the material code for mineral oil, U the European certification (PED), 330 the permissible pressure in bar, A the thread according to ISO 228 (BSP), and 125 is the precharge pressure p0 at 20 °C, in bar, according to the structure in the document.
Which bladder is chosen for a fluid other than mineral oil?
The HYDAC document lists NBR, ECO, IIR and FKM, each with its temperature range and compatible fluids: for example FKM between -10 and +150 °C, ECO between -30 and +120 °C. You can send us the data for your fluid and temperature; we check the table in the document.
What should be specified for a quotation?
The full code or the nameplate, the precharge pressure p0, the country of installation (the certification code depends on it) and, when replacing only the bladder, the diameter of the smaller connection of the vessel.
Other Hydac series
The data come from standard document 3.201; the low-pressure (3.202) and high-pressure (3.203) series are separate HYDAC documents. Dimensions, weights and article numbers for each volume are read from the document table for the exact code.
Updated: 2026-11-12