In 3rd year heavy duty right now, quit caffeine this week and have been a zombie but of course i zone out during lectures on all these valves, here for review. Thanks for all this!
These are nice lectures. It would be very handy if you would point to the line that your speaking about (or somehow highlight it) so that it is clearer. Also, directionality of flows would be useful.
Hi , hope you are good. Wanted to know your views on Pressure reducing valves. When I checked, seems that they all have internal leakage through their pilot line. I mean , for a pressure reducing valve to work , the pilot line must drain oil to tank. So if any pressure reducing valve is connected to an accumulator, it will drain the accumulator till the preset pressure is reached and pilot drain flow will stop ! Am I right? Can pressure reducing valves be used with accumulators? For example, can we have a 3 way pressure reducing valve without internal leakage? Do we have any models of 3 way pressure reducing valves without leakage? Does leakage happen when valve is off ? For e.g suppose I have a 3 way proportional pressure reducing valve; when valve is off , output pressure is zero. If this valve is connected to an accumulator, will it drain all accumulator oil little by little? Will leakage occur when valve is off ? Thanks. Kind Regards.
Hello sir, Pressure reducing valve works like digital or analogue? When pilot pressure reaches set value, Will this pressure reducing valve close the flow through it & maintain the output static pressure constant untill there is no actuator actutates in system OR Will the pressure reducing valve allows continuous flow through it at reduced pressure equal to set value?? Please reply.
As a pump guy in the southeast, pressure relief valves are not always between the pumps and the tank as they are on Carroll Childers stations, all VFD stations I've seen have a PRV valve. No tanks
True dat. A "rupture disc" also qualifies as a low tech pressure relief valve that doesn't necessarily require a tank. (Although it's a recommended practice to route the discharge somewhere!)
Isn't the constant reduction pressure reducing valve essentialy a hydrostat or pressure-compensated pressure reducing valve and the symbol wil be slightly different in the circuit as the drain port to tank wil be connected across as orifice in pre pressure-compensated valve, post pressure compensated wil be different connection as the keep pressure differential or delta P constant as to keep the flow through an metering device constant such as as a flow control or DCV constant trough a variation in load induced pressure? Help me if I'm wrong. Thanks for the good content. Love your videos.
Yes, there's a bunch of different ways to draw pressure reducing valves. Classic example not mentioned in this lecture: sometimes pressure reducing valves also feature a pressure relieving action (ie: if branch pressure ever exceeds the set point because of some outside force or thermal expansion it will relieve pressure) that is illustrated schematically as an arrow in (reducing) and an arrow out (relieving). Check out th-cam.com/video/fCNNFz48Si8/w-d-xo.html
I don't understand that Pressure reducing valve has another line of check valve(one way) around pressure reducing valve. When pump rises pressure through pressure reducing valve, can fluid go directly into check valve before entering to actuator, circulating the fluid. How does check valve work? When pressure reducing valve is open, does check valve is closed in both direction?
If a actuator connected to reducing valve requires pressure more or less than 250PSI to be actuated, then how does reducing valve will maintain 250PSI pressure in circuit.
Here's a hypothetical situation: 1) main pressure relief valve set to 1000psi 2) pressure reducing valve set to 500psi 3) actuator requires 250psi to extend using straight through position of directional control valve 4) pressure reducing valve is normally open so when directional control valve is moved into straight through position fluid flows and pressure rises to 250psi sufficient to extend actuator. 5) When actuator stalls at limits of travel, pressure rises to 500psi at which point pressure reducing valve closes and prevents further rise beyond 500psi. 6) If pressure in this leg ever drops below 500psi pressure reducing valve briefly opens and permits fluid entry until pressure again rises to 500psi. 7) retraction bypass the pressure reducing valve in reverse.
Jim, I appreciate you explaning a PRV. Yet, your wise cracks/jokes TAKE AWAY from the teaching and are CONFUSING. Please find a better way to give examples or make a point!
In 3rd year heavy duty right now, quit caffeine this week and have been a zombie but of course i zone out during lectures on all these valves, here for review. Thanks for all this!
Please tell your fellow students about these free lectures if you ever catch them zoning out in class too!
Blown away by the lecture and the explanation!! Thank you
Good videos Jim. It's a good review of a class that I took.
finally someone understands the lab partner scenario
So useful thank u so much. Well explained . so happy .😊
These are nice lectures. It would be very handy if you would point to the line that your speaking about (or somehow highlight it) so that it is clearer. Also, directionality of flows would be useful.
Keep the jokes and stay real. Ignore the haters. Legit information as allways!
Hi Jim, how do I know when to use a 3.7 and 7.6 pressure reducing valve? Thanks.
thanks really appreciate.
very very good thanks
Hi , hope you are good. Wanted to know your views on Pressure reducing valves. When I checked, seems that they all have internal leakage through their pilot line. I mean , for a pressure reducing valve to work , the pilot line must drain oil to tank.
So if any pressure reducing valve is connected to an accumulator, it will drain the accumulator till the preset pressure is reached and pilot drain flow will stop !
Am I right? Can pressure reducing valves be used with accumulators? For example, can we have a 3 way pressure reducing valve without internal leakage?
Do we have any models of 3 way pressure reducing valves without leakage?
Does leakage happen when valve is off ?
For e.g suppose I have a 3 way proportional pressure reducing valve; when valve is off , output pressure is zero. If this valve is connected to an accumulator, will it drain all accumulator oil little by little? Will leakage occur when valve is off ?
Thanks.
Kind Regards.
Check out the differential unloading relief valve: th-cam.com/video/eJ05rODkYFg/w-d-xo.html
@@bigbadtech thank you 👍👍
Do direct acting pressure reducing valves without leakage to tank actually exist? Or all models include leakage ! Thanks.
Hello sir, Pressure reducing valve works like digital or analogue? When pilot pressure reaches set value,
Will this pressure reducing valve close the flow through it & maintain the output static pressure constant untill there is no actuator actutates in system OR
Will the pressure reducing valve allows continuous flow through it at reduced pressure equal to set value??
Please reply.
Sir injunction molding machine back pressure valve How it works
As a pump guy in the southeast, pressure relief valves are not always between the pumps and the tank as they are on Carroll Childers stations, all VFD stations I've seen have a PRV valve. No tanks
True dat. A "rupture disc" also qualifies as a low tech pressure relief valve that doesn't necessarily require a tank. (Although it's a recommended practice to route the discharge somewhere!)
Isn't the constant reduction pressure reducing valve essentialy a hydrostat or pressure-compensated pressure reducing valve and the symbol wil be slightly different in the
circuit as the drain port to tank wil be connected across as orifice in pre pressure-compensated valve, post pressure compensated wil be different connection as the keep pressure differential or delta P constant as to keep the flow through an metering device constant such as as a flow control or DCV constant trough a variation in load induced pressure? Help me if I'm wrong. Thanks for the good content. Love your videos.
Yes, there's a bunch of different ways to draw pressure reducing valves. Classic example not mentioned in this lecture: sometimes pressure reducing valves also feature a pressure relieving action (ie: if branch pressure ever exceeds the set point because of some outside force or thermal expansion it will relieve pressure) that is illustrated schematically as an arrow in (reducing) and an arrow out (relieving). Check out th-cam.com/video/fCNNFz48Si8/w-d-xo.html
Hello from Brazil, Jim. How can I contact you other than by TH-cam, please! Thank you very much
Check the FAQs first ... th-cam.com/video/e0KxcU_-ggY/w-d-xo.html If you still need to get in touch with me do a search on the college website
Look Jim something wrong with the check valve.
Before reaching limit pressure oil will go from the check valve.
I don't understand that
Pressure reducing valve has another line of check valve(one way) around pressure reducing valve.
When pump rises pressure through pressure reducing valve, can fluid go directly into check valve before entering to actuator, circulating the fluid.
How does check valve work?
When pressure reducing valve is open, does check valve is closed in both direction?
Check it out: th-cam.com/video/J6n6QYIwhHw/w-d-xo.html
Yes you are right something wrong with check valve
If a actuator connected to reducing valve requires pressure more or less than 250PSI to be actuated, then how does reducing valve will maintain 250PSI pressure in circuit.
Here's a hypothetical situation:
1) main pressure relief valve set to 1000psi
2) pressure reducing valve set to 500psi
3) actuator requires 250psi to extend using straight through position of directional control valve
4) pressure reducing valve is normally open so when directional control valve is moved into straight through position fluid flows and pressure rises to 250psi sufficient to extend actuator.
5) When actuator stalls at limits of travel, pressure rises to 500psi at which point pressure reducing valve closes and prevents further rise beyond 500psi.
6) If pressure in this leg ever drops below 500psi pressure reducing valve briefly opens and permits fluid entry until pressure again rises to 500psi.
7) retraction bypass the pressure reducing valve in reverse.
Thanks Jim
Full volume on my earphones. Still can't hear.
Jim,
I appreciate you explaning a PRV.
Yet, your wise cracks/jokes TAKE AWAY from the teaching and are CONFUSING.
Please find a better way to give examples or make a point!