Hydraulic Valves Intended for Use in Potentially Explosive Atmospheres
Typical operating limits of size 06, CETOP03 versions. Ambient temperature 70 °C (158 °F), Voltage Un -10 % (24 VDC), Power Pn 10 W
There are potentially explosive mixtures in the form of gas, vapor, mist or dust in various segments of the chemical and petrochemical industries or for example in mines. It is necessary to ensure a high level of protection against explosion on each part of the equipment used in these industries. When using hydraulic elements, a common method is to prevent the accumulation of energy, which would be sufficient for the ignition of an explosive mixture. Specifically it means, that the development of these elements will focus on preventing explosive mixtures from entering a space where they can cause sparks. We used two types of protection on the electrical parts of our valves: Type „Ex e“ - increased safety for the connection terminal on DC coils and type „Ex mb“ - encapsulation on our AC coils with a rectifier bridge.
It is also important to limit the maximum surface temperature of the individual parts of the valve.
Hydraulic fluids in this of applications usually reach operating temperatures of about 55 °C.
This temperature is much lower than the maximum allowed temperature of the individual parts. Therefore the hydraulic part of the valve cools the whole assembly. The only part on which the surface temperature has to be reduced, is the solenoid. A significant reduction of the surface temperature is achieved by means of a solenoid design that allows better heat radiation from the solenoid to the surroundings and also a reduction of the power consumption of the solenoid.
This reduced power consumption normally results in a lower hydraulic performance of the valve. Therefore, valves designed for explosive environments, typically transmit lower hydraulic power than conventional valves.
ARGO-HYTOS, being in valves development and production for more than 60 years, has launched a new Directional Modular and Screw-in Valve range on the explosion proof market to overcome this typically low hydraulic power phenomenon.
The new One4All explosion solenoids are designed for all explosion risk areas and temperature classes in combination with modern CFD design methods, resulting in a unique hydraulic power performance of explosion proof valves. We offer two basic ranges of Modular Valves and Screw-in Cartridge versions.
Our One4All 10W solenoids, intended for use in potentially explosive atmospheres in combination with the valve design, reach similar results as conventional 30 W solenoids. The unique design also allows to open the electrical terminal box cable installation without losing the ATEX / IECEx certificate’s validity.
Features
Additionally, our Explosion Proof Valves bear all unique features applied for the standard ARGO-HYTOS valve range as
- Robust design for 10 Mio. life cycles, also applied for sealings
- Screw-in Cartridge Poppet Valves with 0 drop leaks and a pressure rating of 420 bar
- Screw-in Spool Valves with a “tumbling nose“ to compensate misalignments of the valve cavity = spool never blocks
- High oil / ambient temperatures as standard
- Surface protection 500 h ISO 9224 as standard
- Special spool versions on request as detent
- GOST TR (Russia Federation) Certification for all explosion proof ranges
- Bayonet manual override – mining, mechanical impact, proved for all CETOP and SIC
- Solenoid interchangeability between CETOP and SIC explosion proof range