Safety units for hydraulic accumulator Safety and shut-off units are used to enhance safety, block and balance the pressure of hydraulic accumulators and consumers. They meet the safety regulations for hydraulic accumulators in the various countries, in particular the pressure vessel regulations in force in Germany. Depending on the version, the presssure in the accumulator and/or consumers is balanced manually or electrically using a solenoid-operated two-way valve. A current control valve that regulates the amounts of pressure fluids in or out can also be installed. olaer accumulator catalogue accumulator safety block rexroth The DI 20 size is also available in a fully stainless steel version.