In a cylinder circuit, when using logic elements to emulate a four-way directional valve function, minimising decompression shock when changing from extend to retract can be a challenge. The larger the volume of oil being compressed (ie, the larger the cylinder bore and/or stroke), the larger the 'shock' potential due to the stored hydraulic energy.
Since this stored energy in the cap end of a cylinder is a 'fact of life' (and do not forget that the machine frame and product being compressed can also add to the total stored energy), the goal is to release this energy in a controlled and consistent manner, in the shortest time that will achieve an 'acceptable' decompression rate (which is usually determined subjectively). The use of dedicated decompression circuit components (ie, staged pilot ratio check valves, orifices, solenoid valves controlled using electrical time delay logic) can be expensive, have questionable reliability, are not always consistent, and consume excess cycle time.
A simplified solution is by using Sun DK*R Balanced Logic Elements with a 2-way DAAL-*CN pilot valve and a Sun PRDB pressure reducer/reliever, the result is a zero leak, reliable, consistent, uncomplicated, and cost effective cap-end-to-tank, normally closed logic element. (A DO*R cartridge can be used in place of the DK*R if a normally open function is desired. Either cartridge can also include Sun's T-8A cavity, ie, DK*R-8 and DO*R-8, to accommodate the pilot control function as an integral unit.) Since this product is 'balanced', operating pressures on the work ports have no effect on the opening speed of the valve. (A typical 'poppet style' logic element exposes more and more area as the poppet moves to the open position, with the attendant increase in opening force.) So, by adjusting the pilot pressure via the reducer, an acceptable and repeatable opening time can be easily set. This approach has proved to be an acceptable solution in minimising decompression shock in the shortest time with consistent results. (Using the newer DAAL-SCN 'soft shift' 2-way as the pilot valve, can further enhance tuning for shock reduction.)
NOTE: Using Series 4 size cartridges, flows up to 80 gpm (320 L/min) with a nominal 100 psi (689 kPa) pressure drop can be achieved. However, when even larger flows are required, two, three and four DKJR logic elements have been successfully applied in parallel and have accommodated flows up to 320 gpm (1280 l/min). (With multiple elements, an external pilot valve sized for the number of cartridges involved, would be required in lieu of integral solenoid pilots in each element.) Also, keep in mind that a balanced logic element can be used as a standalone valve in a machine with a common spool valve circuit if that machine is experiencing excessive decompression shock.
Control without complexity Axiom Hydraulics
Electrical switching & drive systems & components
In an era where precision, performance and smart control define industrial success, the right driver can make all the difference. At Axiom Hydraulics, we’ve seen firsthand how the Sun Hydraulics XMD series transforms hydraulic systems, from mining and construction to agriculture and automation.
Read more...Monitoring vibration allows for equipment longevity Iritron
Other technologies
Unscheduled downtime and maintenance on machines is often a source of frustration for many companies active in industrial manufacturing as it results in loss of process and productivity, which in turn equates to loss of revenue.
Read more...Building resilience in extreme environments
Other technologies
The petrochemical and oil and gas sectors operate in unforgiving environments. In this high-stakes industry, operational efficiency is vital, and unplanned downtime can have severe consequences. To thrive in this demanding landscape, a proactive and sophisticated approach to maintenance is no longer an option, but a necessity.
Read more...Extending oil drain intervals
Other technologies
In a recent field study, African Group Lubricants tested the performance of Mobil Delvac Modern MX 15W-40 Super Defense engine oil under rigorous operational conditions. The goal was to extend the oil drain interval while maintaining optimal engine performance and reliability.
Read more...Latest advance in automotive cooling fluids
Other technologies
The automotive industry is undergoing a significant transformation, driven by advancements in vehicle design and increasing demands for enhanced performance and durability. These changes are bringing a marked shift toward formulations that offer improved heat dissipation and robust corrosion resistance.
Read more...Advancements in wire rope testing
Other technologies
Being able to get instant, real-time and portable detection of wire rope flaws can make a significant difference for operational teams. There have been a number of significant technological advancements and tools entering the market that help wire rope operators detect and resolve problems faster.
Read more...Complete solutions for the die casting industry
Other technologies
Die casting is a manufacturing process that involves injecting molten metal into a mould to produce complex, high-precision components. FUCHS Lubricants South Africa addresses the evolving demands of the die casting sector through continuous product innovation and development.
Read more...Rethinking common approaches to wire rope lubrication
Other technologies
: Wire ropes are hard-working components in many different applications, from mines to lifts, ports, construction sites and drainage systems. Correct lubrication of wire ropes is absolutely critical because wire ropes are more than just cables, they are intricate machines composed of interdependent parts in constant motion.
printer friendly version