Prince LV series valves

[samohn]

Hello to all.

I am in need of replacing the loader valve on my 89 Deutz Allis 5220 and, after doing some research, am interested in the Prince LV series valves. I am having a lot of trouble finding pricing for these valves, or any online sites that sell the valves for that matter.

I was just going to ask the opinion of everyone on the board of the Prince LV series valves and if there are any other better options for me.

Thanks for your help.

Scott

 

[bruceatlam]

Like this one??????


https://www.surpluscenter.com/item.asp?UID=2009050613583975&item=9-7693&catname=

 

[samohn]

Bruce,

Thanks for the quick reply. I guess I should have been more specific. Having reviewed the LV series valves, I was trying to find the "LVS series circuit" valve. This is what I could not find on the Surplus City website.

The Prince website explains that the series configuration offers multifunction operation as opposed to the parallel configuration.

I may not quite understand the difference between series and parallel. I did do a search on this, but was somewhat confused by the explanation that was provided.

Thanks

Scott

 

[bruceatlam]

Found a short older thread:

http://www.tractorbynet.com/forums/parts-repairs/87973-prince-lvs-loader-valve-similar.html

 

[kennyd]

Surplus Center has joystick valves for $200 and under...Why are you so interested in the LV series?

 

[samohn]

Maybe I am reading too much into it. I read the info on the Brand valves and also on the Prince valves. I just want to get a good, reliable valve that had minimal drift for my tractor. If the Brand valves are good, then they may be an option. Prince valves seem to have a good reputation. I have had issues in the past with drift and currently have major drifting issues with my Deutz which I believe to have mostly pinpointed to the valve.

Having previously owned a Kubota L3710 with a 681 loader, I really liked the meterability of the valve and the fact that drift was almost non-existent. That is was I am looking for with my Deutz.

If you feel the Brand valve will provide this, then I will certainly consider them.

Maybe I am also reading too much into the series versus parallel concept. Any direction here would be helpful as well.

Thanks for the help.

Scott

 

[samohn]

To add to my above comments. What I specifically dont understand about the whole series / parallel thing is as follows:

The Prince LVS valve states that it is "monoblock with series circuit construction"

The Prince LVT and LVR valve states that they are "monoblock with parallel circuit construction"

Apparently the differences are within the valve itself.

My question is What is the advantage of one over the other?

Scott

 

[kennyd]

Sorry Scott for leaving you hangin'

I have no comment on the series/Parallel issue for you...it's a little above my pay grade unfortunately. I can say that several members hear have used the Brand series valves and been happy with them.

 

[3RRL]

Click on this link and scroll down to page 4:
Valve Circuit Types ... Series/Tandom/Parallel
It gives a pretty good explanation of the different kinds of circuits and combination(s) there of.
Rob-

 

[samohn]

Thank you all for your responses. I have contacted the Surplus Center (Thanks kennyd for referencing them in a lot of your posts. They are easy to deal with) and ordered the Prince Lvs series valve. Based on the descriptions and the research I have done the series valve works a lot better when multi-functioning the loader as I frequently do with working dirt.

Thanks again.

Scott

 

[Farmerford]

Scott:

Multiple-spool valves can be configured as parallel, series, tandem, or certain combinations. They all send exactly the same volume and pressure of fluid to a cylinder when only one spool is activated. The difference arises when more than one spool is activated at the same time. For simplicity assume a two spool valve and that when a spool is activated it is fully rather than partially shifted. The differences among the configurations are greatest for a full shift.

The parallel valve allows both circuits to receive fluid directly from the pump at the same time. There is no downstream valve in a parallel system. It is like two sprinkler hoses connected to a "y" connector at the faucet. Fluid can flow to whichever circuit has the lowest backpressure. As a practical matter, if the backpressures in the circuits are close to the same, fluid will flow to both circuits at once.

If an FEL has a parallel valve, when both spools are shifted (say to curl and lift) the bucket cylinders and boom cylinders are all connected to the pump. Oil flows to the cylinders with the lowest resistance (in terms of pressure, not force). If the bucket is empty, on most loaders the bucket will curl fully before the boom moves; once the bucket curls fully and the bucket cylinders stop, they will accept no more fluid and all the fluid then flows to the boom cylinders.

One of my FEL's with parallel valves has an interesting combination of reactions. If I start with the boom down and the bucket parallel to the ground, and then fully shift both valves (they are parallel) the boom lifts about four feet and the bucket does not move (so I assume the boom cylinders have the lowest backpressure), but then the boom stops lifting and the bucket curls fully, and once the bucket curls fully the boom again lifts. In that case, the boom resistance was less than the bucket until the boom raised four feet, then the bucket resistance was less so fluid stopped flowing to the boom and flowed to the bucket until it reached the limit of travel.

I prefer the parallel valve for a FEL because I am lazy (or perhaps just slow witted). When loading loose material with the bucket I can fully shift both the boom and bucket spools and keep them shifted until the boom rises fully and the bucket curls fully. I don't have to feather the valves to send fluid to one circuit or the other; that happens automatically because of the nature of the valve. The fluid flows until both circuits reach their stops. The cylinder sizes, linkage geometry, etc. are such that the bucket curls fully first, then the booms lift the load.

The tandem valve has an upstream valve (receives pump flow first) and a downstream valve (receives pump flow last). When the upstream valve is shifted fully all pump flow is directed to the upstream cylinder and none will go to the downstream cylinder even if it is shifted. If the booms are connected to the upstream valve then when the boom is being lifted (again assuming a fully shifted valve) the bucket will not move since all flow will go to the booms. Once the boom reaches the desired height the boom valve must be returned to neutral in order for the bucket valve to receive fluid.

The series valve has an upstream valve and a downstream valve like the tandem valve, but with an important difference: when the upstream valve is shifted the return flow from the upstream cylinders passes through the downstream valve rather than to the tank. Therefore, if both valves are shifted, the downstream valve receives not fresh fluid from the pump (as it would if the valves were parallel) but rather the exhaust fluid coming out of the upstream cylinder. The advantage is that both valves receive the full volume of flow from the pump and therefore both the boom and the bucket move at the same speed when both valves are shifted that they do when only one is shifted. This is useful when the pump volume is lower than desirable for fast movement.

The series valve has disadvantages. Once the upstream cylinder reaches its limits and stops moving, the downstream cylinder will stop moving also since it depends on the outflow from the upstream cylinder. And since the flow from the pump passes through both sets of cylinders the pump pressure is divided between the cylinders. That is, a 2000 psi pump will not produce the equivalent of 2000 psi of force in both the boom and bucket cylinders at the same time; the total 2000 psi pump pressure will be divided between the cylinders. Thus, if you have a heavy load, the combined resistance of the boom and bucket may be greater than the pressure of the pump, in which case both actions will not happen at once. Finally (and this is the most significant disadvantage to me) the series valve takes more thinking when working with a heavy load: you first try both the boom and the bucket at the same time to see if the pressure is sufficient to move both; if not, then you choose the one to move first and hold the valve in that position until it moves fully; then you shift the valve to the other action until it moves fully. Of course, if the pump pressure is sufficient to move both the boom and bucket at the same time, the cycle time for lift and curl will be much shorter than for a parallel valve since both the boom and bucket are moving at maximum speed.

The tandem and series valve can be made to act (somewhat) like the parallel valve by feathering (partially shifting) the upstream spools. In each case only partially shifting the upstream valve allows some pump flow to pass directly to the downstream valve where it will be directed to the downstream cylinder if the downstream valve is shifted. However, this bypassing fluid suffers a pressure loss passing through the upstream valve equal to the pressure in the upstream cylinder because of the blocking effect of the upstream spool.

Your questions suggest you will make the effort to obtain the time savings from the series valve. We all look forward to receiving a report on how it works for you.

Good luck.

 

[samohn]

Farmerford,

That was an exceptional explanation of the differences in the valves. Thank you for taking the time to write that.

I agree with everything you said and would like to add a few comments to your last paragraph explaining the disadvantages of the series valve. When you state the the downstream valve stops receiving flow once the upstream cylinder stops moving, you are assuming that the spool is fully shifted. If it is not, then some flow will go to the downstream circuit.

I would also add that any valve configuration, series, parallel or tandem, will split the available pressure if multifunctioning. This phenomenon is not limited to the series valve only.

As with most of the folks on this board, I have operated several different tractors utilizing different valve configurations over the years. Prior to my purchase of the Deutz Allis, I had a Kubota L3710 which had the series valve. For my operating style, this was the best running loader and smoothest functioning valve I had ever operated.

The valve I ordered from The surplus center was backordered for 30 days. Once I get it installed I will certainly provide a report.

Thanks again for providing your expertise on the valve configurations.

Scott

 

[AKKAMAAN]

Farmerford did a great job explaining this......
Open center systems are more difficult to operate when you have to use multiple functions (actuators) at the same time....and their speed and force depends on the load pressure in the actuator....the actuator with the lowest load pressure will get highest priority on oil flow, (get oil first)...

An open center system have a directional valve that,...

when spool is in neutral, and the whole pump flow goes through the center back to the reservoir....

when spool is fully stroked, the center is fully closed and the whole pump flow goes to work port, A or B....

when spool is partially stroked, spool is between neutral and fully stroked, the pump flow is split between the center and the work port.... this is how you make a slow gentle motion on your actuator....but all the flow (times the pressure) that goes thru center back to tank will be an energy loss....and can cause overheating in your system....

It is common that overheating problems is caused by operating with partially stroked spools, operator don't know or understand what going on in the system...if half flow go to tank , then half the energy will convert into heat in oil......

When purchasing mobile equipment like excavators, cranes on logging equipment etc...with 2-6 functions that will be operated simultaneously, a hydraulic system with a variable pump, closed center and constant pressure, is so much easier to operate....so I think that is something that really have to be considered....look for Constant Pressure Unloaded, CPU or Load Sensing, LS, system...

Watch these movies, it how precise operator handle the crane with 3" tall joysticks, it is a loadsensing hydraulic system, Constant pressure, with Electro hydraulic servo controlled spool valves....
The harvester head is automatic and computer controlled and operated by small touch buttons below the joy sticks......

YouTube - John Deere 1270D with 754

YouTube - Forworder valmet

Per A
20+ years experience from teaching hydraulic on logging equipment and training operators in Sweden

 

[samohn]

Finally got my valve from the Surplus Center and got it installed. WOW! What a difference. The multifunctioning ability of the series style valve is incredible. Far superior, in my opinion, to a parallel valve.

I would strongly recommend going to a series style valve if ever needing to replace your loader valve.

Thanks again for everyones help and explanations concerning this.

Scott

 

[GIJOE]

Which valve did you get? Can you post a link or a model number?

Joe

 

[samohn]

Joe,

Below is the configuration for my valve.

LVS1AGR5B1-25

I have attached the Prince LVS brochure which shows how to configure the valve part number.

Scott