The FOX HST Series Diaphragm Accumulator – Repairable is an essential technical component for managing pressure variations and correctly storing energy in modern hydraulic circuits. Precisely designed to meet the strict requirements of the industrial sector, this hydropneumatic accumulator stands out for its threaded execution and full repairability, ensuring quick maintenance operations and extended operating life cycles.

Operating Principle and Applications

Operation is based on a recommended compression ratio of P2/P0 = 2.5, with the possibility of reaching a maximum tolerated ratio of P2/P0 = 6. However, the mechanical life of the component is inversely proportional to the increase in this compression ratio. For applications that require the accumulator to be used specifically as a pulsation damper, it is essential to set the precharge pressure between 60% and 80% of the actual working pressure, carefully considering both the type of pump used in the system and the specific operating temperature value. Installation offers great versatility, as it can be carried out either horizontally or vertically, with the only essential precaution being to keep the nitrogen valve constantly facing upwards.

Construction Features and Materials

From a construction standpoint, the FOX HST Series Diaphragm Accumulator – Repairable is equipped with a robust body made entirely of painted carbon steel, capable of withstanding a maximum working pressure (PS) of 300 bar. The test pressure (PT) is equal to PS multiplied by 1.43, 1.3 or 1.5, thereby ensuring wide operating safety margins. The precharge system uses a standard 5/8″ UNF nitrogen valve. In addition, depending on requirements, the external painting can follow the standard FOX procedure or comply with specific project specifications.

Fluid Specifications and Operating Temperatures

The standard diaphragm supplied is formulated to be perfectly suitable for use with mineral oils and non-aggressive fluids. The standard operating temperature range (TS) is between -20°C and +80°C, excellently covering most conventional industrial requirements. For operating conditions with extreme temperatures, however, the LT Series can be requested, specifically designed to operate at temperatures as low as -40°C. In terms of elastomer composition, diaphragms can be supplied in special compounds such as HNBR, EPDM, FPM and HYTREL, further expanding chemical compatibility with process fluids.

Customizations and Series Variants

The entire range has been developed in different volumes, up to 20 litres, allowing adaptation to any system size and flow requirement. Numerous technical variants are available upon request, including internal coatings in different materials for special fluids and special flanged connections, including SAE 3000, SAE 6000, ANSI B16.5 and UNI/DIN configurations. In addition to the standard version, it is possible to choose the M Series, rechargeable via M28x1.5 nitrogen valve, the V Series, supplied as non-rechargeable with a fixed precharge value established directly at the time of ordering, and the S Series, which operates as a fluid separator. Finally, the product can be certified upon specific engineering request in strict compliance with a wide range of international regulatory standards, including CE (PED), ATEX, ASME VIII and various other global certification bodies.

Technical Summary Table