single to double conversion

[Arkwright]

I have a vacuum machine for picking up horse manure in the field. The dung is collected in a 1 cubic metre hopper which can be dumped with the Stone electric pump and a single acting hydraulic cylinder. That works fine -- so long as the manure slides out! Sometimes it doesn't and there is no way the hopper will return to normal (horizontal) position unassisted. As the back door it now facing downwards, within about six inches of the ground, it is impossible to fork the material out. The solution is to put a hose pipe into the hopper and hope the wetted material will slide out in time!

I'd like to convert the dump using a double acting cylinder so the hopper can be up righted using the hydraulic pump. At least, then, it can be forked out manually or the manure loosened so it slides out.

Would it work if I use the exisiting single acting pump with a manual diverter valve and replace the single acting cylinder with a double acting cylinder? I think I would need to make some provision for the hydraulic fluid to drain back into the tank. Maybe through a modified filler cap? Is there anything else I should be aware of? I am new to hydraulics but it occurs to me that the system I want will be something on the lines of a hydraulic log splitter? I see that Stone also make double acting pumps, but I'm hoping I won't need one of those.

Incidentaly, the cylinder has one connection for the fluid and also a blanking plate at the other end of the cylinder. I had assumed this latter was a breather but there doesn't seem to be a hole in it. Is there any chance this could be modified to be double acting? Pump is illustrated below.

Thanks for your time.

 

[J_J]

You could add spring assist to help the cylinder return.

You could add another cylinder to pull the hopper back down, and use a selector valve to switch cylinders.

You could also use a DC linear electric actuators for the return.

https://www.surpluscenter.com/item.asp?UID=2009110806294855&item=5-1577-6&catname=electric

 

[kennyd]

Can you supply a model number of the pump/motor unit?

 

[Mark_in_NH]

This won't help answer your question but. What is the purpose for picking up the manure in the field ?
All my years of growing up on the farm, we used to collect the manure from the barn and go purposly Spread it on the Field.

 

[Mike120]

Sorry, I can't help you either, but I'll echo Marks question....I've seen the pull behind vaccums in ads but never could figure out why someone would buy one. Because I've got a breeding / training operation I usually have 25-30 horses on the place. Those that are showing go in the barn and their manure/bedding gets spread in the hay fields. The manure in the paddocks gets broken up with a chain drag before the paddock is rested. I considered collecting it for compost but that's more effort than I think it's worth. What do you do with it?

 

[Redneck in training]

I know a guy who boards horses. He developed a forced air manure burner/furnace and uses it to heat the barn. It is outside unit with a big hopper that he loads with dry horse manure it will run unattended for several days controlled by thermostat the same way as gas furnace.

 

[Arkwright]

This won't help answer your question but. What is the purpose for picking up the manure in the field ?
All my years of growing up on the farm, we used to collect the manure from the barn and go purposly Spread it on the Field.

I'll answer this one first!

I am in Scotland, UK. Worms can be a problem over here. The worm eggs are spread via the feces, hatch in damp warm weather, and the larvae can then reinfect horses. It is possible for infections to get so bad that the horse can become quite ill, even die in extreme cases. Probably not a problem in a dry climate or on a large acreage especially when cross grazing with other species. Harrowing in our climate is reckoned to spread worm eggs which can live up to 12 months in dung.

Control is by medication which is expensive. Picking up the dung removes the worm eggs at the same time. This is dumped in a heap which will heat up during decomposition killing the eggs. I am hoping to put the dung back on the fields as manure (also expensive these days) when it has rotted down and the eggs are dead. Removing the dung also helps the grass as grazing horses tend to avoid patches where they have defecated which are then taken over by weeds. Does that make sense?

Off to get serial numbers. This forum is great!

 

[Mark_in_NH]

Ok, those answers satisfy my curiosity. thanks

 

[Arkwright]

The pump is a STONE Code UD2570, serial number 0109889, working pressure 130 bar.

The web page for this machine is here: Predator People the ultimate paddock vacuum cleaner - predator lynx

Even when empty, the hopper needs manual assistance to return it to horizontal. When full, but contents stuck, it needs considerable force to return to normal but only to pass the centre of gravity.

I like the idea of a second cylinder with a selector valve.

The existing cylinder has a connector near the base for input of the hydraulic fluid. There is a similar connector at the top of the cylinder, near the rod, with a blanking plug in it. This does not appear to be a breather as there is no hole in it. (Can't work out where the air goes!).

I did speak to the technical department of a hydraulics manufacturer and was told some cylinders are manufactured as double acting but only used as singles as it is cheaper to make one type. Is that possible or have I misunderstood?

If I replaced the existing single acting cylinder with a double acting, would I also need a two stage pump?

Thanks for your help.

 

[kennyd]

The pump is a STONE Code UD2570, serial number 0109889, working pressure 130 bar.

The web page for this machine is here: Predator People the ultimate paddock vacuum cleaner - predator lynx

Even when empty, the hopper needs manual assistance to return it to horizontal. When full, but contents stuck, it needs considerable force to return to normal but only to pass the centre of gravity.

I like the idea of a second cylinder with a selector valve.

The existing cylinder has a connector near the base for input of the hydraulic fluid. There is a similar connector at the top of the cylinder, near the rod, with a blanking plug in it. This does not appear to be a breather as there is no hole in it. (Can't work out where the air goes!).

I did speak to the technical department of a hydraulics manufacturer and was told some cylinders are manufactured as double acting but only used as singles as it is cheaper to make one type. Is that possible or have I misunderstood?

If I replaced the existing single acting cylinder with a double acting, would I also need a two stage pump?

Thanks for your help.

I can't find any info on that pump setup

But from the webpage you linked it says:

Hydraulics:
12volt 3 inch slim line motor
125 bar pressure.​

Single stage 500mm stroke double acting ram.​

But you only have one hose to the cylinder?
Are they any unused ports on the pump housing?
Does the pump run when you are lowering the dump?

It is very possible to use the DA (dual acting) cylinder as a SA (single acting) and you may just be a DA cylinder-there is however "usually" a vent on the unused port rather than just a plug

Here is something to try-just a feeling I have-and it's free...Take the plug out of the cylinder and see if it dumps better. It is possible that since the port is plugged the piston is having to suck air past the seals causing the resistance you are feeling.

 

[Mike120]

I am in Scotland, UK.

Having lived in Aberdeen a couple of times and spent much of my youth at Nigg Bay and Ardersier, I completely understand your logic. Good luck in fixing your vacuum!

 

[Arkwright]

I can't find any info on that pump setup

But from the webpage you linked it says:


But you only have one hose to the cylinder?
Are they any unused ports on the pump housing?
Does the pump run when you are lowering the dump?

It is very possible to use the DA (dual acting) cylinder as a SA (single acting) and you may just be a DA cylinder-there is however "usually" a vent on the unused port rather than just a plug

Here is something to try-just a feeling I have-and it's free...Take the plug out of the cylinder and see if it dumps better. It is possible that since the port is plugged the piston is having to suck air past the seals causing the resistance you are feeling.

I spent most of the day vacuuming horse poo with the machine today!

I removed the plug at the top of the cylinder. As I was unscrewing it, there were a few tiny air bubbles and a few drops of oil but there is definitely no hole in the plug. It is a plain blanking plug.

I worked the ram a few times and air seems to be escaping on the downward stroke around the seal around the rod.

As you can see from the pictures, there is only one hose. But there is also a blanking plug (?) on the pump.

Half the problem to emptying is a lip around the sides of the hopper exit door which inhibits the material simply sliding out. The fancy moulding on the sides of the hopper, presumably for stiffening, doesn't help either. I was thinking that fixing a flat surface (chloroplast?) on battens to the insides (to remove all these obstructions) would help emptying.

But the major problem is returning the hopper to horizontal after it has been tipped. Even when empty, it needs manual assistance and if there is material stuck inside the hopper it is impossible to upright. And to clean it out with a fork when in this position would need a contorionist!

I have not had much help from the people selling this machine as I suspect they will be dealing mostly with lady horse owner customers who don't question these things. Also, I don't think they know -- hence the item about DA hydraulics on the web page when it is clearly SA.

Any comments you can make would be very helpful as I know next to nothing about hydraulics.

 

[kennyd]

Bummer, I was hoping take the plug out would help...It "looks" like a DA cylinder to me so it should have a vent-NOT a plug.

I would contact the motor/valve manufactures and see if that unit you have can operate a DA cylinder, I see a plug next to where the hose connects? That will be the best solution.

Does the motor run when you lower the dump?

 

[Kubota 2350]

That looks just like the hyd pump on my travel trailer for moving the slid outs in and out.
Will the pump run in reverse?
If it will, the other plug on top in the picture can be used for the other port on the cylinder to make it have force going back down.

 

[FLHayman]

I have a number of single acting cylinders on my farm equipment that are, in fact, double acting cylinders with little plugs on one side that have a mesh/breather built in to the plug, to theoritically stop contamination as the cylinder returns to original position driven by the weight of the implement. In all cases of mine, they can be changed to dual acting simply by adding a line to the 2nd port on the cylinder. In your case, that would involve running the pump in reverse (not necessarily built into the pump design) or adding an open center reversing valve. On my tractors, there is no great reason to have them be single acting except to simply save the extra hose, since I have to have a 3 position valve, (up, hold, down) or a float detented valve (up, hold, down, float: all valves open) to allow it to gravity-return to parked position.

Looks to me from the picture, like you could add a valve and a hose to force the cylinder back into parked position. All cylinders that I have used will accept hydraulic pressure from both sides of the piston inside. I know there are specialized ram cylinders that use pressure from one side only, but that one sure looks like a regular cylinder.

 

[Arkwright]

"Does the motor run when you lower the dump?"

No. It is meant to return by gravity.

"Will the pump run in reverse?"

No. But the manufacturers seem to make a number of similar units with different specs. See here:

http://www.stonehydraulics.com/productfamilies.aspx?sPgPh=Power Units&sPoductId=8&Application=DC Power Units

Also here: Both single and double acting pumps listed.

eBay Seller: floridahoseguys: Business, Office Industrial items on eBay.co.uk

"Looks to me from the picture, like you could add a valve and a hose to force the cylinder back into parked position. All cylinders that I have used will accept hydraulic pressure from both sides of the piston inside. I know there are specialized ram cylinders that use pressure from one side only, but that one sure looks like a regular cylinder."

For this cylinder to operate DA, wouldn't the internal seals need to be changed? At the moment, when it extends, air appears to be forced out through the seal around the rod at the end of the cylinder and hydraulic fluid would go the same way. Unless, of course, there is a pump that will suck (pull) as well as blow (push). This is something I just don't know about and rely on you guys for advice.

Again, wouldn't there need to be a second hose (return) to return the used fluid back to the reservoir if set up to work double acting?

 

[kennyd]

"Does the motor run when you lower the dump?"

No. It is meant to return by gravity.

Yes, gravity. But the valve has to let the fluid back to the tank somehow-so when you push the "lower switch" something let that happen-I was just curious if the pump ran during that time.

"Will the pump run in reverse?"

No. But the manufacturers seem to make a number of similar units with different specs. See here:

http://www.stonehydraulics.com/produ...px?sPgPh=Power Units&sPoductId=8&Application=DC Power Units

That link does not work. But lets try this one Stone Hydraulics Can you verify the model number you have?

For this cylinder to operate DA, wouldn't the internal seals need to be changed? At the moment, when it extends, air appears to be forced out through the seal around the rod at the end of the cylinder and hydraulic fluid would go the same way. Unless, of course, there is a pump that will suck (pull) as well as blow (push). This is something I just don't know about and rely on you guys for advice.

No, the seals are the same. The air can be compressed and forced past the rod wiper seals whereas the fluid cannot. This is why I thought removing that plug would help, so the air could easily escape.

Again, wouldn't there need to be a second hose (return) to return the used fluid back to the reservoir if set up to work double acting?

Yes, a second hose from the top cylinder port back to the control valve.

Ultimately, I think the cheapest solution will be to talk to Stone and see what it will take to upgrade your pump to operate a DA cylinder-then add the extra hose.

Please verify the model of the power unit you have...

 

[J_J]

Seems to me that if it was originally designed to power up and gravity down, then, there is something not working correctly.

Actually air in the rod chamber doesn't have anything to do with the force of the single acting cylinder, but if the air can not escape out of the breather, then the piston will force the air out of the seals. I don't think that is how it is supposed to work. If the base side fluid is released, then the weight of the box should be enough to suck in air and collapse the cylinder. So perhaps the valve controlling the cyl is not working correctly.

Springs could pull the box back down if the fluid is released from the base end, but if it has to work to suck in air just to let the rod retract by weight, it may hang up or no do anything. .

Perhaps someone took out the breather and put a plug in it's place. Take the plug out and see if the cylinder works like it is supposed to. If it works good, put a filtered breather plug in there.

Quote:

Problems arise with conventional breathers in that fine screens can often plug up such that air will not pass through them as required for proper operation, while coarser screens can allow dust to enter the barrel and damage the walls and sealsof the hydraulic cylinder. As well moisture can condense in, or be drawn into, the barrel, especially when operating in humid conditions or rain, causing rust and corrosion and premature failure of the cylinder.

 

[J_J]

Maybe go this route . A double acting cyl and a log splitter valve. Push lever to dump, and pull lever back for auto return. Maybe less than $150 for valve and cylinder

 

[Arkwright]

"Does the motor run when you lower the dump?"

No. It is meant to return by gravity with the fluid returning to the reservoir by the same hose..

"Yes, gravity. But the valve has to let the fluid back to the tank somehow-so when you push the "lower switch" something let that happen-I was just curious if the pump ran during that time".

No, it should return with gravity but the hinges on the hopper are not positioned correctly in relation to the centre of gravity, especially when the hopper is full (see picture ). If the hopper return is started manually (i.e I pull it back down by hand), it lowers OK, but I need to keep my finger on the lower button on the remote as I do so. Presumably a valve opens in the pump to allow the fluid to flow back to the reservoir.

"Can you verify the model number you have?"

JJ asked this question above. It is a STONE Code UD2570, serial number 0109889, which isn't listed on the web site. It occurs to me that the whole hydraulic system was possibly supplied as one unit (pump, cylinder, hoses, etc) in quantity to the manufacturer to fit to the vacuum machine so is a one off -- but I could be wrong.

Very interested to read from Kennyd that the seals are the same in SA and DA cylinders. Learn something new every day! I tried operating the ram with the plug removed and it did not make the slightest difference to the speed.

"Ultimately, I think the cheapest solution will be to talk to Stone and see what it will take to upgrade your pump to operate a DA cylinder-then add the extra hose".

That sounds like good sense. I did speak to Stone's agents here in the UK but I'm afraid I was lost in the techno-speak! From the look of the web site, parts for the pump can be changed according to the function required.

"Seems to me that if it was originally designed to power up and gravity down, then, there is something not working correctly".

Yes, but when the hopper is in the tipped position, it has moved beyond the centre of gravity as you can see in the picture. I think that is the problem. It is bad design. That's why return has to be manually assisted when empty and it is impossible to return manually when full. The hopper stuck in the dump position again today when the contents refused to slide out (horse poo is surprisingly sticky!). I solve the problem as I usually do by putting a hose pipe in the inlet port and going for a cup of coffee! When water logged, the manure usually slides out OK but that method is time consuming and I am getting caffene poisoning!.

"Perhaps someone took out the breather and put a plug in it's place. Take the plug out and see if the cylinder works like it is supposed to. If it works good, put a filtered breather plug in there".

See above in this post. I did that and it made no difference. The machine is brand new so I think it is meant to be like that.

"Maybe go this route . A double acting cyl and a log splitter valve. Push lever to dump, and pull lever back for auto return. Maybe less than $150 for valve and cylinder".

That sounds good. I now have enough information to research this further. I live in a fairly remote location and informed advice is difficult to get. There are three hydraulics shops within 100 miles. Two of these mostly sell stuff off the shelf. The third (the furtherest away) is very good but also very busy so they are not really interested in my small problems!

Thanks a lot, guys. I don't know where I would have got this advice if not here.