I can’t believe I just stumbled upon this video randomly and ended up spending an hour on late Monday night learning and taking notes about pressure relief valves… amazing lesson! Thank you sir! 😄 By the way the pressure drop at the balance orifice is described by the Poiseuille’s Law (I believe), I’m just leaving it here as knowing that really enabled me to understand how these valves work.
Question. @40.11 pressure below 950psi keeps the poppet closed because of pressure balanced through the orifice. Then that means it should balance after 950psi. But it doesn't why?
Nice video. Can please send me the drawings of one PRV and the combined drawing with the two PRV valve. I like to understand the design concept and the appropriate selection. Thanks.
I do have a question What will happen if I replace a gear hydraulic pump with 22 cm/rev to 42 cm/rev What will happen in my system 🤔? Another question is the relive valve gonna send the unneeded oil to the tank ?
we did replace control block )whole set) ...than found main drum pay out not functioning but pay in / swing and boom functioning were still functioning...please advise thanks...
Often a vent port is available with a balanced, pilot operated relief valve yes. The vent port can serve several functions including a system unloading one like you mentioned. This function is usually about allowing pilot pressure outward, towards tank, as opposed to applying pilot pressure 'into' this port. A true and dedicated unloading valve while similar is also a little bit different from a relief valve.
Why did the pilot valve start oil leakage to tank at 950bar? Shouldn't it have started at 500bar since it is similar to the relief valve without a pilot in previous slide?
Great question. The pilot poppet surface area and the pilot spring is much smaller for the very small pilot flow volume, and thus the override properties for the pilot section of the balanced, pilot operated relief valve are different from the poppet and spring properties of a direct acting relief valve that would be large enough to handle full pump flow.
Hi sir I am kannan ,Chennai India, hydraulic system normal running time oil high temperature, how can normal temperature without use air cooler,water cooler, and jiller units ,
To try out the simulations for yourself, take a look at our Pressure Relief Valves session: www.lunchboxsessions.com/explore/hydraulics/pressure-relief-valves
Is there a name for valves that are a combination of basic valves? Such as the piloted relief valve with an orifice and two relief valves as one component.
Really enjoyed the lesson and learnt something useful! Would love to see videos on NG 6 or NG 10 stack/sandwich valve configurations for PT dcv for a single ram or multi ram configurations. Thanks and please keep em coming!
You're a very good teacher. I'm moving into a new roll at a very large aerospace company where I will be calibrating hydraulic systems. I am being trained on site by an individual with over 35+ years of experience in this field and I am using your video to help me "brush up" before I start in 2 weeks. I have 15 years in aerospace working on building complex tools for precision drilling on the structure. Now I am moving into metrology / calibration. Thank you for your amazing ability to teach and your expansive knowledge!
Instructor is awesome. Not demeaning to the students at all, but instead explains everything to help them understand. So to me, I knew that series of dots was the spring in the relief valve. But for the student who asked, the instructor not only confirmed that it was the spring. But also explained that it’s the industry symbol for a spring cutaway. I respect the hell out of that.
your sessions are very informative and properly broken down. Gained a lot from you sir and really appreciate the way you deliver the knowledge and makes us ease to understand. Lot more misconceptions have been cleared, in my learning.
Static and dynamic pressure, flow , uncompressed and orifice. After this lesson, I understand how balanced main poppet works. Load increase, static pressure increase, pilot poppet crack, flow created, Pressure difference between orifice inlet and outlet, main poppet starting open. This lunchbox session is great. Thank you.
