The FOX Special Series Bladder Accumulator with Flanged Connections is a large-scale hydropneumatic storage solution, ideal for integration into complex, high-capacity hydraulic systems. Designed to ensure maximum reliability in industrial environments, this device features an intelligent top-repairable design, a construction configuration that greatly simplifies and speeds up all inspection and maintenance operations, reducing system downtime.

Construction Features and Materials

The main structure of the HG series accumulators is made using high-strength carbon steel. For marine, chemical or other applications requiring superior corrosion resistance, the manufacturer offers the special HGX series, made entirely of AISI 304L or AISI 316L stainless steel. The accumulator body is usually supplied with an external coating applied according to the standard FOX procedure, but customised coatings can be requested to meet specific project requirements. The capacity range is among the widest on the market, offering volumes starting from 100 litres and reaching the impressive value of 5000 litres, meeting the needs of accumulators for extremely high-power systems.

Operating and Functional Specifications

In terms of performance, these devices are tested to operate with a maximum working pressure (PS) of up to 50 bar. The strict test pressure (PT) applied during testing is calculated using coefficients of 1.43, 1.3 or 1.5 in relation to the nominal working pressure, ensuring wide structural safety margins. The permitted operating temperature range (TS) extends from a minimum of -20°C to a maximum of +80°C, allowing operation in countless industrial scenarios. The recommended and optimal installation position is strictly vertical, taking care to keep the nitrogen valve facing upwards. To maximise the mechanical life of the component, which is inversely proportional to the increase in the compression ratio, it is recommended to maintain a P2/P0 ratio of 2.5, never exceeding the tolerated technical limit of 4. If the accumulator operates as a pulsation damper within the circuit, the nitrogen pre-charge pressure must be calculated and maintained between 60% and 80% of the working pressure, a parameter that must always be assessed in relation to the type of pump installed and the operating temperatures.

Bladder Variants and Fluid Compatibility

The operating core of the accumulator, namely the bladder, is supplied as standard in polyurethane. This polymer stands out for its excellent chemical compatibility with the most common mineral oils, fuels and non-aggressive hydraulic fluids. To meet specific pumping requirements involving chemically complex fluids or non-standard temperatures, FOX provides alternative bladders made from special compounds such as IIR, NBR, FPM or ECO. The nitrogen pre-charge valve, positioned at the upper end, is a standard type with 5/8″ UNF or M28x1.5 thread.

Flanged Connections and International Certifications

Secure connection to the hydraulic circuit is ensured through the use of high-seal flanged connections. The construction variants include connections by means of SAE 3000, SAE 6000, ANSI B16.5 or UNI/DIN flanges, ensuring global interoperability. Customised connections can be produced upon specific request. As evidence of its high quality and safety standards, the accumulator can be supplied with the most important international certifications, including CE (2014/68/EU-PED), ATEX (2014/34/EU), ASME VIII Div.1/Div.2, KOSHA, SELO, DNV/RINA and numerous other approvals for the global market.

Summary Technical Table