November 20, 2014 - Rexroth introduces pilot-operated LFA_DB_-7X/_E 2/2 directional pressure relief cartridge valves that ensure high flow and pressure.. The safety valves type-examination tested under the Pressure Equipment Directive 97/23/EC simplify hydraulic circuits and reduce inspection effort during operation in addition to material and installation costs. The cartridge valves eliminate the need for previously necessary components in stationary hydraulic systems and contribute to reducing manufacturing and operating costs, as well as reducing the overall installation space needed in the block. With a relief pressure of 190 bar and a delivery volume of 3,500 l/min, this valve replaces up to 15 cartridge units.
At 350 bar and 5,000 l/min, the ratio is 1:9. A size 63 cartridge valve can replace more than 10 existing single valves. This substantially reduces material and installation costs, as well as inspection effort. In addition to reduced material costs, the valves significantly reduce installation time. Standard safety is certified through a type examination by TÜV Süd.
The porting pattern for the safety valves is in accordance with ISO 7368 (Form B) and also allows retrofitting in installed systems. The pressure limiter is integrated into the sealed control cover. The relief pressure is configured to the desired maximum value and sealed at the factory. In addition to a fixed maximum setting, Rexroth also offers a version that can be adjusted to lower pressure values at no additional charge. These can greatly simplify mandatory routine functional testing, which also reduces maintenance costs.
The standard shaft seal of the main spool eliminates internal leakage. This means the valves do not cause any power loss. At the same time, they enhance robustness against the “silting effect”, which can result in malfunctions primarily in short switching cycles due to screen filtration. Rexroth offers the LFA_DB_7X/_E safety valves in sizes 40, 50 and 63 with 4 graduated pressure ranges between 50 and 400 bar. They convey flows of up to 5,000 l/min.
