Safety Blocks Parker Olaer has developed a complete range of decompressing and isolating blocks (sizes 10 to 50) to answer all standard and special applications. These blocks are in conformity with the European Directive on the equipment under pressure (97/23), these appliances have  been designed to group together in a single compact unit all the components necessary for the correct operation of a hydraulic system equipped with hydropneumatic accumulators. The basic block consists of : Isolating valve to isolate the accumulator from the circuit for all the blocks except from model DI 10 where it also ensures the decompression function. A drain valve for decompressing the accumulator for all models (except DI 10) A pressure limiting valve EC with poppet calibrated generally to the maximum service pressure of the accumulator (under no circumstances must this appliance be used to protect the hydraulic pump) Pressure tapping port (M) In the E version, the basic block, to decompress the accumulator, can be equipped with an electro-valve : 2 ways 2 positions (DI 10/DI 20/DI 32) cartridge type. 3 ways 2 positions (DI 16/DI 24) with impact of connection according to DIN 24340 Form A, ISO 4401 and CETOP RP 121 H.