Two New Actuators From Danfoss
By Mike Osenga06 December 2017
Danfoss Power Solutions has introduced two new actuators. The new PVE series 7 are designed to work in conjunction with Danfoss’ PVG 32, PVG 100, PVG 120 and the new PVG 128 and PVG 256 proportional valves, as well as EHPS, EH, EHi and OSPE model steering valves.
Also new are the PVE-EX series actuators certified for use in explosive atmospheres and incorporating closed loop spool position control and event monitoring technology. The PVE-EX actuators are targeted primarily at mining and the offshore oil and gas markets.
Standard for all proportional PVE Series 7 actuators is the use of a spool position feedback signal to close the loop on the PVG/steering valve main spool position, ensuring it is in the right position at a given input signal, Danfoss said. This ensures high precision of the valve flow with high repeatability.
Danfoss PVE Series 7 actuators come with built-in safeguards, including fault monitoring and options of spool direction indication, spool position feedback and separate float control. The enhanced spool position sensor with dual demodulator increases the diagnostic coverage to make the actuators safer and more reliable. “With this advanced diagnostics system, we are checking that the spool position signal is not corrupted, ensuring high reliability,” said Knud Meldgaard Jensen, global product marketing manager for Danfoss Power Solutions.
Other features of the new PVE Series 7 include the ability to upgrade to the new PVE Series 7 actuator from PVE Series 4, as it is 100 percent backwards compatible with PVE Series 4 actuators. There is also more space available around the valve due to the compact design of the new PVE Series 7, giving OEMs better design flexibility, Danfoss said.
An increased temperature range from -40o to 194o F (-40 to +90 °C), allows the PVE Series 7 to operate in extreme conditions. Easy system upstart and event monitoring is enabled by LED lights on all actuators, so the electronic wiring can be tested without powering up the hydraulic system.
Danfoss added that machine EMC testing is enhanced when upgrading from the PVE Series 4 to PVE Series 7 as the PVE Series 7 is E-marked according to UNECE R10.
Approved and certified according to ATEX and IECEx standards, the new PVE-EX enables the use of PVG valves in harsh environments with explosive atmospheres. Designed with a cast iron enclosure, the PVE-EX protects the interior connectors and embedded electronics, while a protective coating on the exterior provides corrosion protection.
The PVE-EX ex db protection variant uses a flame-proof protection method, which is crucial for use in underground mining applications and oil & gas markets. “For example, the Ex db is designed to enable easy inspection of the flame paths. In addition, this design solution enables the cable and cable harness to be changed out quickly, minimizing downtime,” Jensen said
Standard for all Danfoss PVE actuators is the use of a spool position feedback control signal to close the loop on the PVG valve main spool position, ensuring it is in the right position at a given input signal. Danfoss PVE actuators also come with built-in safeguards such as event monitoring and an optional output for spool direction.
The top cover on the PVE-EX can face forward or backward for easier installation and thus reduce complexity within the wiring harness. The modular design concept allows the PVE-EX to be installed into existing solutions with a cable connection through protected screw terminals. An 0-10V control signal variant is available which compliments the standard portfolio of ratio metric signal actuators.
PVE-EX actuators are certified for use in oil and gas applications (group IIB) as well as underground mining (group I) including: Mining Products Safety Approval and Certification Center (MA)(China); European Regulatory Framework for Manufacture, Installation and Use of Equipment in Explosive Atmospheres (ATEX)(EU); International Electrotechnical Commission Standards Relating to Equipment for Use in Explosive Atmospheres (IECEx)(EU); and Mine Safety and Health Administration (MSHA)(U.S.).