The latest addition to Sterling Hydraulics' range of CE marked pressure relief valves is the A04B2*CE. Like their leading CE marked A04J2 valve, the new valve is fully compliant with the pressure equipment directive (PED 976/23/EC) and is rated to the highest level, Category IV. The PED relates specifically to equipment which has a high stored energy level.

This includes, for example, nitrogen-charged accumulators that retain pressurised oil for release on demand, to operate an hydraulic service, such as a vehicle braking system.

Category IV covers a variety of applications including hydraulic fluid power equipment.

A major element of this category is the stored energy rating of the system, as dictated by the volumetric capacity and the operating pressure.

Full details of category ratings and whether equipment needs to comply with the PED can be found in the Conformity Assessment Tables in Annex II of the PED.

In particular, Sterling Hydraulics' CE valves meet the requirements of Modules B and D of the PED.

Module B is the EC type examination, in which a representative sample of products from a production batch is independently checked for compliance.

Module D covers quality assurance for production, final inspection and testing, as described in the EC type examination certificate or the EC design certificate.

Category IV is the highest safety level defined by the Directive, and equipment rated for Category IV is also suitable for use in systems with hazard ratings which fall into Categories I, II and III.

To meet the Category IV rating, equipment must be safe; must meet essential safety requirements covering design, manufacturing and testing; must satisfy appropriate conformity assessment procedures and must carry the CE mark.

The CE (Conformitee Europeenne) mark is a compliance symbol awarded by the Committee for European Construction Equipment (CECE) which recognises that the product meets all the requirements of EU legislation for safety to the consumer and the environment.

'European safety requirements are defined in the Machinery Directive, together with the appropriate European Standards,' says Laurence Card, Sterling Hydraulic's Principal Valve Engineer, and a member of the BFPA/BSI Technical Committee for fluid power products, 'Only a machine that carries the CE mark is guaranteed to meet these requirements, and can be traded in every country of the European Economic Area'.

' That may sound like bureaucracy, but if a contractor allowed the use of non-CE marked construction equipment and an accident occurred as a result, he could face serious consequences'.

' The CE mark on our relief valves means that OEMs in the European Union can incorporate these valves into their own CE marked machines with total confidence.' The A04J2 is a high flow bi-directional relief valve that can handle pressures up to 350bar and flows up to 120 litre/min in either direction'.

''It is a very popular valve,' says Card, 'Although discussions with our OEM customers suggested that higher pressure ratings would be needed in the future.' The latest demand has been for a uni-directional valve, of less complex design and not necessarily bi-directional flow capability.

Its poppet-style construction ensures low leakage whilst the hardened working parts provide for maximum durability.