Hydraulic sorting gates, Part 4: Valves

The brains of a hydraulic sorting system are the valves. These are what takes fluid that is flowing thru the circuit and divert it into a cylinder or motor to do work for you. In this post, we will go over the basic options you have for valves on a hydraulic gate system.

The type of circuit that you will use determines the type of valve that you need to buy. The circuit that I like to use for these types of gates is called an “Open center”. This means that when the valve is in the neutral position (not being actuated) the fluid flows thru and back to the tank or the next valve.

It doesn’t matter if you are using manual valve, or electric valves, or even some other option, you need to make sure your valves are open center. The reason I like to use this system is that you want fluid to always being flowing thru the system. It allows for faster response time, but more importantly in cold climates, it allows the fluid to always be flowing thru the valves and keeping them at a warmer temperature.

The fist option for valves is a simple set of manual valves. These are pretty simple to set up. There is usually an “IN” and an “OUT” port and then 2 ports above each handle that go to the cylinder. The fluid flows from the “P” port on the pump, to the “IN” port on the valves. The “OUT” goes to the “T” and returns to the tank.

The only thing to say about using manual valves is that you need to be careful about the length of the hoses that connect your valve to your cylinder. If they are too long, you will have problems with the fluid not getting cycled out of the hoses. This happens when the displacement in the hoses is significantly less than the displacement in the cylinder, or the amount you allow a motor to displace during 1 cycle.

The problem will be that the fluid will never warm up and if there are air pockets in the system, they will never come out. This can cause erratic performance and be very frustrating. This problem can be mitigated by using a high pressure quarter turn valve in between the “A” and “B” ports at the cylinder. When you start a day, open the quarter turn valve and then open the control valve for a few minutes. This will allow all fluid in that circuit to circulate back to the tank. Do it 1 time, then actuate the cylinder (extend or retract it) and circulate the fluid a little more to have all new fluid in the hoses.

This method can work on motors that do not operate enough in one cycle to move the fluid back to the tank. However it’s also possible to simply take the belt off or pull otherwise mechanically disconnect the motor and run it.

There’s really nothing else to say about these valves, they work just about anywhere you put them, and they are very robust.

Manual valves on a chute. The two valves on the right are used to operate sorting gates in front of the chute. The total length of hose is about 50’, which is near the maximum that this system works well.

Manual valves on a chute. The two valves on the right are used to operate sorting gates in front of the chute. The total length of hose is about 50’, which is near the maximum that this system works well.

The next two types of valve are the same, but with a different mounting system. This is using electric actuated hydraulic valves. These are used on anything that is using a switch to move something with a cylinder. A good example is a chute on a feed wagon, or any movement that is controlled by a computer on a tractor.

The valves that we use are a standard type of valve that is commonly available, that way it is easily replaceable. The ones I like to use are a little more expensive, but they are easy to work on and have an easy way to manually override. The cheaper options work as well.

The first way to mount them is to take all of your valves that you need and put them on one manifold. Manifolds can range in size from a single version (which is called a sub-plate) up to 8 or even 12 valves in a line. When selecting a manifold, you need to be sure to buy a “Series” type, not a “parallel” type. Take care to install the valves correctly as it is sometime possible to put them on backwards.

This system works well when you have many cylinders to control in a close area. For example, if you have a hydraulic tub and hydraulic adjustments on your alleyway, using a system like this is best. Where it doesn’t work as well is where you have several cylinders to control and they are spread out where you have lots of hose between the valve and the cylinder. In this case, you want to use the second mounting option.

A bank of 7 valves mounted on a single manifold. The valves are inside a large toolbox to protect them from the weather.

A bank of 7 valves mounted on a single manifold. The valves are inside a large toolbox to protect them from the weather.

The second way to mount your hydraulic valves is to mount them on single sub plates and put them close to your gate. You want to have them in a protected place, not where they can get hit by cow or tractor, and it’s really nice if you can put them in an enclosure. I have found that a 12x12 electrical enclosure works really well. It’s just the right size and gives you both nice protection and cleans up the look as well. It’s also easy to work with, just poke holes with a hole saw to run hoses and conduit into it.

With this system, you will run a hose from “P” on the pump put to the first " “P” on the first valve in the line. Then the hoses will go from the “T” to the next “P” to make a chain of valves. The last valve will usually then have fluid coming out the the “T” and it will return to the “T” on the pump unit, completing the circuit.

This system works best for sorting gates in front of your chute and gives you much better performance, even in very cold weather.

Electric valve inside a 12 x 12 PVC box.

Electric valve inside a 12 x 12 PVC box.

No matter which valves you choose for your system, take care in mounting them. Electric valves are pretty tough, but they have some weaknesses. On the electrical side, the valves are sealed up pretty good, and I have had some mounted outside for over 12 years, but it’s still a good idea to put them in a box to keep them out of direct moisture. Always make sure to keep wiring tied up and sealed up as well as you can.

The electric valves are vulnerable to contaminates in the fluid jamming up the valves. The magnets do not have as much force as you do pulling on a lever. If you have some sand or rubber in your hoses, it can jam up a system. This is most likely to occur the first 1 or 2 times you use it and rarely happens after a system is “broke in”. Excellent filtration will help with this and we will talk about that at a later date.

I hope you found this helpful. If you have any questions, don’t hesitate to ask, I love chatting about corrals and hydraulics! Make sure to follow on social media, especially Facebook where I post regularly. (links at the bototm)